Wikipedia - User contributions [en]

El Tiro Gliderport

2023-12-08T19:18:47Z

Blastr42: /* Gallery */

{{Short description|Gliderport in Pima County, Arizona}}
{{Infobox airport
| name = El Tiro Gliderport
| image = USGS via TopoQuest of El Tiro Gliderport.jpg
| IATA =
| ICAO =
| FAA = AZ67
| type = Private use; permission required prior to landing
| owner =
| operator = Tucson Soaring Club, Inc.
| city-served =
| location = [[Pima County, Arizona]]
| timezone =
| elevation-f = 2100
| elevation-m = 640
| coordinates = {{coord|32|25|37.25|N|111|23|22.39|W|type:airport_region:US}}
| website = http://tucsonsoaring.org/
| pushpin_map = USA Arizona#USA
| pushpin_map_caption = Location of airport in Arizona
| pushpin_label = '''AZ67'''
| pushpin_label_position = right
| r1-number = 8L/26R
| r1-length-f = 1300
| r1-length-m = 397
| r1-surface = [[Asphalt concrete|Asphalt]]
| stat1-header =
| stat1-data =
| stat-year =
| footnotes =
| r2-number = 8/26
| r2-length-f = 5120
| r2-length-m = 1561
| r2-surface = Dirt
| r3-number = 8R/26L
| r3-length-f = 5000
| r3-length-m = 1524
| r3-surface = Dirt
| r4-number = 17L/35R
| r4-length-f = 5000
| r4-length-m = 1524
| r4-surface = Dirt/treated
| r5-number = 17R/35L
| r5-length-f = 5000
| r5-length-m = 1524
| r5-surface = Dirt/treated
| stat2-header =
| stat2-data =
}}

'''El Tiro Gliderport''' {{Airport codes|||AZ67}}, formally '''[[Marana Auxiliary Army Airfield No. 5]]''' ('''[[Sahuaro Field]]'''), is marked on the Phoenix [[sectional chart]] is a [[Non-towered airport|non-towered]] private use [[Airport|gliderport]] {{cvt|23|mi|nmi km|lk=on}} northwest of [[Tucson, Arizona]], United States.<ref>{{Cite web|url=http://www.airnav.com/airport/AZ67|title=AirNav: AZ67 - El Tiro Gliderport|website=www.airnav.com|access-date=2018-04-03}}</ref> The airport property is leased from the [[Bureau of Land Management]] and has been operated by the Tucson Soaring Club, Inc. (a chapter of the [[Soaring Society of America]]) since 1983.<ref>{{Cite web|url=http://files.leagueathletics.com/Text/Documents/2280/8617.doc|title=Tucson Soaring Club Introduction for New Members June 2008|website=TUCSON SOARING CLUB}}</ref><ref>{{Cite web|url=https://azjewishpost.com/2015/gliding-is-peaceful-pastime-for-tucsonan/|title=Gliding is peaceful pastime for Tucsonan, AZ Jewish Post|website=Arizona Jewish Post|language=en-US|access-date=2018-04-03}}</ref><ref>{{Cite web|url=http://tucsonsoaring.org/|title=Tucson Soaring Club|website=tucsonsoaring.org|access-date=2018-04-03}}</ref>

'''Marana Auxiliary Army Airfield No. 5''' (aka '''Sahuaro Field''') was one of five auxiliary fields that served [[Marana Army Air Field]] (now [[Pinal Airpark]]) and is one of many [[Arizona World War II Army Airfields]]. Sahuaro Field first appeared on the Phoenix [[sectional chart]] in 1945. The airfield was originally described as a "{{cvt|206|acre|lk=on}} square-shaped property having a {{cvt|3000|ft|m|lk=on}} square [[Asphalt concrete|asphalt]] landing mat." After [[World War II]] there is evidence of the airfield being used by the [[United States Air Force]] in 1957 for pilot training in [[North American T-6 Texan]] and [[T-28 Trojan]] aircraft. From 1958 the airport was reportedly abandoned until Tucson Soaring Club leased the property.<ref>{{Cite web|url=http://www.airfields-freeman.com/AZ/Airfields_AZ_Tucson_N.htm#Sahuaro|title=Abandoned & Little-Known Airfields: Arizona, Northern Tucson area|website=www.airfields-freeman.com|access-date=2018-03-18}}</ref><ref>{{Cite web|url=http://www.maranaaz.gov/airport-history/|title=Airport history|website=Town of Marana|language=en-US|access-date=2018-03-18}}</ref>

== Facilities ==
* 8L/26R measuring {{cvt|5000|x|100|ft}}, [[dirt]]
* 8L/26R measuring {{cvt|1300|x|22|ft}}, [[Asphalt concrete|asphalt]], [[superimposed]] on 8L/26R
* 8/26 measuring {{cvt|5120|x|100|ft}}, dirt center
* 8R/26L measuring {{cvt|5000|x|100|ft}}, dirt
* 17L/35R measuring {{cvt|5000|x|100|ft}}, dirt/treated
* 17R/35L measuring {{cvt|5000|x|100|ft}}, dirt/treated

===Old runways===
* 4L/23R {{cvt|3300|x|280|ft}}, asphalt
* 4R/23L {{cvt|3300|x|280|ft}}, asphalt
* 13L/32R {{cvt|3300|x|280|ft}}, asphalt
* 13R/32R {{cvt|3300|x|280|ft}}, asphalt

==Gallery==
<gallery>
File:Marana_Army_Air_Field_1945_Phoenix_Sectional_Chart.jpg|1945 Phoenix sectional chart shows El Tiro Gliderport as Marana Auxiliary Army Airfield No. 5 (aka Sahuaro Field).
File:United States Geological Survey topo map of Marana Auxiliary Airfield No. 5.jpg|1957 USGS topo map of Marana Auxiliary Airfield No 5
File:Glider and tow plane at El Tiro Gliderport AZ.jpg|[[Grob G103 Twin Astir]] glider preparing to launch in tow by the [[Piper PA-25 Pawnee]] tow plane at El Tiro in 2020
</gallery>

== See also ==
* [[Pinal Airpark]]
* [[Arizona World War II Army Airfields]]
* [[List of airports in Arizona]]

== References ==
<references />

== External links ==
{{US-airport-minor|AZ67|}}
{{Arizona during World War II}}

[[Category:Airports in Pima County, Arizona]]
[[Category:Aviation in Arizona]]

Piper PA-34 Seneca

2023-08-08T04:30:50Z

Blastr42:

{{Short description|Twin engine light aircraft}}
{|{{Infobox aircraft begin
|name= PA-34 Seneca
|image= File:piper.seneca.pa34.g-elis.bristol.arp.jpg
|caption=Piper PA-34-200T Seneca II
}}{{Infobox aircraft type
|type= Business and personal aircraft<ref name="Foster"/>
|national origin= United States
|manufacturer= [[Piper Aircraft]]
|designer=
|first flight= 25 April 1967<ref name="Peperell"/>
|introduced= 1971
|retired=
|status=
|produced= 1971–present
|primary user=
|more users=
|number built= 5037 (until 2019)<ref>Roger Peperell: ''Piper Aircraft – Freedom of Flight, Supplement'', Air-Britain, Tonbridge 2020, {{ISBN|978-0-85130-524-0}}, p. 92–93.</ref>
|developed from= [[Piper Cherokee Six]]
|variants with their own articles= [[PZL M-20 Mewa]]
}}
|}

The '''Piper PA-34 Seneca''' is a twin-engined [[light aircraft]], produced in the United States by [[Piper Aircraft]]. It has been in non-continuous production since 1971.<ref name="Plane and Pilot"/><ref name="Piper"/><ref name="A7SO1"/> The Seneca is primarily used for personal and business flying.<ref name="Foster"/>

==Development==
The Seneca was developed as a twin-engined version of the [[Piper Cherokee Six]]. The prototype was a Cherokee Six that had wing-mounted engines installed, retaining its nose engine. The prototype was flown as a tri-motor aircraft in the initial stages of the test-flying program.<ref name="Foster"/>

===PA-34-180 Twin Six===
With the decision to abandon the three-engined design tested on the PA-32-3M, the PA-34 was developed as a twin-engined aircraft. The prototype PA-34-180 Twin Six, [[Aircraft registration|registered]] as ''N3401K'', first flew on 25 April 1967. The prototype had two {{convert|180|hp|kW|0|abbr=on}} [[Lycoming O-360]] engines, a fixed nosewheel landing gear and a Cherokee Six vertical tail. The second prototype flew on 30 August 1968, still with the {{convert|180|hp|kW|0|abbr=on}} Lycomings but had retractable landing gear and a taller vertical tail. During development flying the wingspan was increased by two feet. The third prototype was closer to the production standard and flew on 20 October 1969; it was fitted with {{convert|200|hp|kW|0|abbr=on}} [[Lycoming O-360|Lycoming IO-360-A1A]] engines.<ref name="Peperell" />

===PA-34-200 Seneca===
Certified on 7 May 1971 and introduced in late 1971 as a 1972 model, the PA-34-200 Seneca is powered by a pair of [[Lycoming O-360|Lycoming IO-360-C1E6]] engines. The righthand engine is a [[Lycoming O-360|Lycoming LIO-360-C1E6]] engine variant, the "L" in its designation indicating that the crankshaft turns in the opposite direction, giving the Seneca counter-rotating engines. The counter-rotating engines eliminate the [[critical engine]] limitations of other light twins and make the aircraft more controllable in the event of a shut down or failure of either engine.<ref name="Plane and Pilot"/><ref name="A7SO1"/> A total of 934 Seneca models were built, including one prototype.<ref name="A7SO1"/><ref name="MM34I"/>

The early Seneca models have a maximum gross weight of {{convert|4000|lb|kg|-1|abbr=on}}, while later serial numbers allowed a takeoff weight of {{convert|4200|lb|kg|-1|abbr=on}}.<ref name="A7SO1"/>

===PA-34-200T Seneca II===
[[File:Piper.seneca.arp.750pix.jpg|thumb|A Piper Seneca II]]
Responding to complaints about the aircraft's handling qualities, Piper introduced the PA-34-200T Seneca II. The aircraft was certified on 18 July 1974 and introduced as a 1975 model.<ref name="A7SO1"/>

The new model incorporated changes to the aircraft's control surfaces, including enlarged and balanced ailerons, the addition of a rudder anti-servo tab, and a stabilator bobweight.<ref name="Plane and Pilot"/>

The "T" in the new model designation reflected a change to turbocharged, six-cylinder [[Continental IO-360|Continental TSIO-360E]] or EB engines for improved performance, particularly at higher altitudes. The Seneca II retained the counter-rotating engine arrangement of the earlier Seneca I.<ref name="A7SO1"/>

The Seneca II also introduced optional "club seating" whereby the two center-row seats face rearwards and the two back seats face forward allowing more legroom in the passenger cabin.<ref name="Plane and Pilot"/> A total of 2,588 Seneca IIs were built.<ref name="aerofiles"/>

Gross weights are {{convert|4570|lb|kg|abbr=on}} for takeoff and {{convert|4342|lb|kg|abbr=on}} for landing, with all weight in excess of {{convert|4000|lb|kg|abbr=on}} required to be fuel.<ref name="A7SO1"/>

===PA-34-220T Seneca III===
[[File:Piper PA-34-220T Seneca III, with one piece windshield.jpg|thumb|Piper Seneca III showing the one piece windshield]]
In 1981, the PA-34-220T Seneca III was introduced, having completed certification on 17 December 1980.<ref name="A7SO1"/>

The change in model designation reflected an engine upgrade. [[Continental IO-360|Continental TSIO-360-KB]] engines were used which produced 220 horsepower (165 kW), although only rated as such for five minutes and then dropping to {{convert|200|hp|kW|0|abbr=on}}.<ref name="A7SO1"/>

The horsepower increase, with the new engines limit of 2800 rpm (up from 2575 rpm), combined for much improved climb and cruise performance. The new aircraft also incorporated a one-piece windshield and a bare metal instrument panel instead of one covered with a removable plastic fascia. Because of the raised zero-fuel weight and the raised maximum take-off weight, the Seneca III has the highest useful load of all the PA-34 variants. Some later models have electrically-actuated flaps. More than 930 Seneca IIIs were built; the last 37 Seneca IIIs built had a 28-volt electrical system rather than the 14-volt system of previous aircraft.<ref name="A7SO1"/>

The aircraft's gross weight was increased to {{convert|4750|lb|kg|0|abbr=on}} for takeoff and {{convert|4513|lb|kg|0|abbr=on}} for landing.<ref name="A7SO1"/> A typical Seneca III with air conditioning and deicing equipment has a useful load of {{convert|1377|lb|kg|0|abbr=on}}.<ref name="POH Seneca III"/>

===PA-34-220T Seneca IV===
In 1994, the "New" Piper Aircraft company introduced the Seneca IV, having achieved certification on 17 November 1993. This model was similar to the Seneca III offering minor improvements, such as a streamlined engine cowl for increased cruise performance. It continued to use the counter-rotating Continental TSIO-360-KB engines and gross weights remained unchanged.<ref name="A7SO1"/> A total of 71 Seneca IVs were built.<ref name="A7SO1"/>

===PA-34-220T Seneca V===
[[File:SenecaV.jpg|thumb|Two examples of Seneca V]]
Certified on 11 December 1996, the Seneca V was put into production as a 1997 model year. Again the cowls were redesigned for increased performance, several cockpit switches were relocated from the panel to the headliner, and an improved engine variant, the [[Continental IO-360|Continental TSIO-360-RB]],<ref name="A7SO1"/> fitted with an [[intercooler]], was used.

The Seneca V's gross weights remain the same as the Seneca III and IV at {{convert|4750|lb|kg|0|abbr=on}} for takeoff and {{convert|4513|lb|kg|0|abbr=on}} for landing,<ref name="A7SO1"/> therefore, with all of the added features, the useful load is reduced by about {{convert|200|lb|kg|0|abbr=on}}. The standard useful load for the 2014 model is {{convert|1331|lb|kg|0|abbr=on}} but typically is {{convert|1134|lb|kg|0|abbr=on}} when the aircraft is equipped with air conditioning, deicing equipment and co-pilot instruments.<ref name="POH"/>

===Embraer EMB-810 Seneca===
From 1975 the Seneca was built under licence in Brazil by [[Embraer]] as the EMB-810.<ref name="Peperell" /> The PA-34-200T was produced as the EMB-810C Seneca (452 built) and the PA-34-220T as the EMB-810D (228 built).<ref name="Peperell" />

==Operators==
[[File:Piper Seneka At Centennial.jpg|thumb|A Piper Seneca II with the engine cowl removed]]

===Civil===

The aircraft is popular with air charter companies and small feeder airlines, and is operated by private individuals and companies. One notable civil operator is the Costa Rican [[Air Surveillance Service]].<ref name="costarica"/>

===Military===
;Brazil
*[[Brazilian Air Force]] (EMB 810C Seneca)<ref name="Flight WAF 88 p31">''Flight International'' 3 December 1988, p.31.</ref>
;Colombia
*[[Colombian Air Force]]<ref name="World Air Forces 2022">{{cite web |last = |first = |url= https://www.flightglobal.com/reports/world-air-forces-directory-2022/146695.article|title = World Air Forces 2022|publisher= Flightglobal |year= 2022 |doi = |accessdate= 18 July 2022|url-access=registration}}</ref>
*[[National Army of Colombia]]<ref name="World Air Forces 2022"/>
;Ecuador
*[[Ecuadorian Air Force]]<ref>Westerhuis ''Air International'' May 2000, p. 280.</ref>
;Honduras
*[[Honduran Air Force]]<ref name="World Air Forces 2021">{{cite web |url=https://www.flightglobal.com/download?ac=75345|title = World Air Forces 2021|publisher= FlightGlobal |date= 4 December 2020 |access-date= 5 January 2021}}</ref>
;Panama
*[[Panamanian Public Forces]]<ref>English 1998, p. 156.</ref>
;Peru
*[[Peruvian Air Force]]<ref name="World Air Forces 2021"/>
;Serbia
*[[Serbian Air Force]] (PA-34-220T Seneca V)<ref>[http://www.flightglobal.com/news/articles/picture-serbian-air-force-receives-multirole-seneca-367496/ Serbian air force receives multirole Seneca] Flightglobal.com</ref>

==Notable accidents and incidents==
* On 2 August 1978 a Seneca carrying [[Richard D. Obenshain]] home from an election campaign event crashed while attempting a night-time landing at the [[Chesterfield County Airport]] (a [[general aviation]] airport near [[Richmond, Virginia]]), killing Obenshain and the other two people on board.<ref>{{cite news|url=https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=40060&key=0|title=NTSB Identification: IAD78FA088|work=[[National Transportation Safety Board]]|access-date=July 27, 2017}}</ref><ref>{{Cite news|last=Harden|first=Blaine|url=https://www.washingtonpost.com/archive/politics/1978/08/04/pilot-of-obenshain-plane-called-very-cautious/fbadce7d-062d-4f46-8e70-04f6118ae205/ |title=Pilot of Obenshain Plane Called 'Very Cautious' |newspaper=[[The Washington Post]] |date=August 4, 1978 |access-date=8 May 2016}}</ref>
* On 18 August 2012 a PA-34-200 Seneca [[2012 Philippine Piper Seneca crash|crashed off the coast of Masbate, Philippines]], killing Philippine Interior and Local Government Secretary [[Jesse Robredo]].<ref>{{cite web|url=http://www.gmanetwork.com/news/story/270304/news/nation/small-plane-with-dilg-secretary-jesse-robredo-crashes-off-masbate |title=Small plane with DILG Secretary Jesse Robredo crashes off Masbate | News | GMA News Online |publisher=Gmanetwork.com |access-date=2012-08-18}}</ref>

==Specifications (PA-34-220T Seneca V)==
{{Aircraft specs
|prime units?=kts

|ref=Piper Seneca V Information Manual ''(October 25, 2005)''
|crew= One
|capacity=Five or six passengers
|length ft= 28
|length in= 7.44
|length m= 8.72
|span ft= 38
|span in= 10.87
|span m= 11.86
|height ft= 9
|height in= 10.8
|height m= 3.02
|wing area sqft= 208.7
|wing area sqm= 19.39
|airfoil= [[laminar flow]] [[NACA airfoil|NACA]] 652-415
|empty weight lb= 3212
|empty weight kg= 1457
|gross weight lb= 4773
|gross weight kg= 2165
|max takeoff weight lb= 4750
|max takeoff weight kg= 2155
|eng1 name=[[Continental IO-360|Continental TSIO-360RB and LTSIO-360RB]]
|eng1 type= 6-cylinder, air-cooled, horizontally-opposed [[piston engine]]
|eng1 number=2
|eng1 hp= 220
|eng1 kw= 164
|max speed kts= 204
|max speed kmh= 378
|max speed mph= 235
|max speed note=at {{convert|23000|ft|m|-2|abbr=on}}
|cruise speed kts= 188
|cruise speed kmh= 348
|cruise speed mph= 216
|cruise speed note=econ cruise at {{convert|25000|ft|m|-2|abbr=on}}
|never exceed speed kts= 204
|never exceed speed kmh= 378
|never exceed speed mph= 235
|stall speed kts= 61
|stall speed kmh= 113
|stall speed mph= 70
|stall speed note=wheels and flaps down
|range nmi= 870
|range km= 1611
|range miles= 1000
|range note=max fuel, econ cruise at {{convert|18000|ft|m|-2|abbr=on}}, no reserves
|ceiling ft= 25,000
|ceiling m= 7,620
|climb rate ftmin= 1550
|climb rate ms= 7.87
|wing loading lb/sqft= 21.2
|wing loading kg/m2= 104
|power/mass=0.1 hp/lb (164 W/kg)
}}

==See also==
{{Portal|Aviation}}
{{aircontent|
|related=
* [[PZL M-20 Mewa]]
|similar aircraft=
* [[Beechcraft Baron]]
* [[Cessna 310]]
|sequence=
|lists=
* [[List of civil aircraft]]
|see also=
}}

==References==
;Notes
{{Reflist|30em|refs=
<ref name="Foster">Montgomery, MR & Gerald Foster: ''A Field Guide to Airplanes, Second Edition'', page 96. Houghton Mifflin Company, 1992. {{ISBN|0-395-62888-1}}</ref>
<ref name="Peperell">Peperell 1987, pp. 227-232</ref>
<ref name="Plane and Pilot">Plane and Pilot: ''1978 Aircraft Directory'', pages 106-107. Werner & Werner Corp, Santa Monica CA, 1977. {{ISBN|0-918312-00-0}}</ref>
<ref name="Piper">{{cite web|url = http://www.piper.com/aircraft/trainer-class/seneca-v/|title = Welcome to the Seneca V|access-date=2017-07-27|last=Piper Aircraft|author-link=Piper Aircraft}}</ref>
<ref name="A7SO1">{{cite web|url = http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/79578854d89e712286257209007693d4/$FILE/A7SO.pdf|title = Type Certificate Data Sheet No. A7SO Revision 17|access-date = 2017-07-27|last = Federal Aviation Administration|author-link = Federal Aviation Administration|date = August 7, 2006|archive-url = https://web.archive.org/web/20090205002738/http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/79578854d89e712286257209007693d4/$FILE/A7SO.pdf|archive-date = February 5, 2009|url-status = dead}}</ref>
<ref name="MM34I">The New Piper Aircraft, Inc., 2003, Introduction, p.2</ref>
<ref name="aerofiles">{{cite web|url = http://www.aerofiles.com/_piper.html|title = Piper aircraft page|access-date = 2010-03-30|last = www.aerofiles.com|date=October 2008}}</ref>
<ref name="costarica">{{cite web|url = http://www.sva.go.cr/galeria/displayimage.php?pos=-472|title = Image of SVA Piper Seneca|access-date = 2010-03-30|last = Official website, Servicio de Vigilancia Aérea del Ministerio de Seguridad Pública Costa Rica}}{{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
<ref name="POH">Piper Aircraft Seneca V Pilot Operating Handbook serial number 3449270, Section 6, Weight and Balance</ref>
<ref name="POH Seneca III">Piper Aircraft Seneca III Pilot Operating Handbook serial number 3448049, Section 6, Weight and Balance</ref>
}}

;Bibliography
* English, Adrian J. "Air Power Analysis:Central America and the Caribbean:Panama". ''World Air Power Journal'', Volume 32 Spring 1998. London:Aerospace Publishing. pp. 142–157. {{ISBN|1-86184-006-3}}. ISSN 0959-7050.
* {{cite book |last=Peperell |first=Roger W |author2=Smith, Colin M | title= Piper Aircraft and their forerunners | year=1987 |publisher=[[Air-Britain]] | location=Tonbridge, Kent, England | isbn=0-85130-149-5}}
* Taylor, John W.R. ''Jane's All The World's Aircraft 1976-77''. London:Jane's Yearbooks, 1976, {{ISBN|0-354-00538-3}}.
* The New Piper Aircraft, Inc. ''Piper PA-34-200 Seneca Airplane Service Manual''; Manual Part Number 753-817, dated October 30, 2003.
* Westerhuis, Rogier. "Fuerza Aérea Ecuatoriana". ''[[Air International]]'', May 2000, Vol. 58, No. 5. pp. 277–281. {{ISSN|0306-5634}}.
* [http://www.flightglobal.com/pdfarchive/view/1988/1988%20-%203428.html?tracked=1 "World's Air Forces 1988"].''[[Flight International]]'', 3 December 1988. pp. 22–87.

==External links==
{{commons category|Piper PA-34 Seneca}}
*{{Official website|http://www.piper.com/aircraft/trainer-class/seneca-v/}}
*[https://web.archive.org/web/20180919132838/http://www.angloeuropean.com/en_GB/aircraft/detailview.php?aid=99 The Piper PA-34 Seneca V - Aircraft images and seat map]

{{Piper}}
{{FAB aircraft designations}}

[[Category:Piper aircraft|Seneca]]
[[Category:1960s United States civil utility aircraft]]
[[Category:Low-wing aircraft]]
[[Category:Aircraft first flown in 1967]]
[[Category:Twin piston-engined tractor aircraft]]

James Webb Space Telescope

2021-12-17T00:52:02Z

Blastr42: added focal ratio under telescope characteristics

{{Short description|NASA/ESA infrared space observatory due to launch in Dec 2021}}
{{Use American English|date=March 2018}}
{{Use dmy dates|date=September 2019}}
{{Infobox spaceflight
| name = James Webb Space Telescope
| names_list = Next Generation Space Telescope (NGST)
| image = JWST spacecraft model 2.png
| image_caption = A rendering of the James Webb Space Telescope with its components fully deployed
| image_size = 300px

| mission_type = [[Space observatory|Astronomy]]
| operator = [[NASA]]{{\}}[[European Space Agency|ESA]]{{\}}[[Space Telescope Science Institute|STScI]]<ref name="jwstPartners">{{cite web|url=https://www.jwst.nasa.gov/faq.html#partners|title=NASA JWST "Who are the partners in the Webb project?"|publisher=NASA|access-date=18 November 2011}} {{PD-notice}}</ref>
| COSPAR_ID =
| SATCAT =
| website = {{URL|https://webbtelescope.org}}
| mission_duration = 10 years (planned)

| manufacturer = [[Northrop Grumman]] [[Ball Aerospace & Technologies]]
| launch_mass = {{cvt|6500|kg}}<ref name="howBig">{{cite web|url=https://jwst.nasa.gov/faq.html#howbig|title=JWST|publisher=NASA|access-date=29 June 2015}} {{PD-notice}}</ref>
| dimensions = {{cvt|20.197|x|14.162|m}}, sunshield
| power = 2 [[watt|kW]]

| launch_date = 24 December 2021, 12:20 [[Coordinated Universal Time|UTC]] <ref name="24dec">{{cite web|url=https://blogs.nasa.gov/webb/2021/12/14/webb-space-telescope-launch-date-update/|title=Update on Webb telescope launch|publisher=NASA|date=14 December 2021|access-date=14 December 2021}} {{PD-notice}}</ref>
| launch_rocket = [[Ariane 5|Ariane 5 ECA]] ([[Ariane flight VA256]])
| launch_site = [[Guiana Space Centre|Centre Spatial Guyanais]], [[ELA-3]]
| launch_contractor = [[Arianespace]]

| entered_service =
| deactivated =
| last_contact =
| decay_date =

| orbit_reference = [[Lagrange point|Sun–Earth L2 orbit]]
| orbit_regime = [[Halo orbit]]
| orbit_periapsis = {{cvt|374000|km}}<ref name="eoPortal">{{cite web|url=https://directory.eoportal.org/web/eoportal/satellite-missions/j/jwst|title=James Webb Space Telescope|publisher=ESA eoPortal|access-date=29 June 2015}}</ref>
| orbit_apoapsis = {{cvt|1500000|km}}
| orbit_inclination =
| orbit_period = 6 months
| apsis = gee

| telescope_name =
| telescope_type = [[Korsch telescope]]
| telescope_diameter = {{cvt|6.5|m}}
| telescope_focal_length = {{cvt|131.4|m}}
| telescope_focal_ratio = {{f/|20.2}}
| telescope_area = {{cvt|25.4|m2}}<ref>{{cite web|title=JWST Telescope|url=https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-telescope|work=James Webb Space Telescope User Documentation |publisher=Space Telescope Science Institute|date=2019-12-23|access-date=2020-06-11}} {{PD-notice}}</ref>
| telescope_wavelength = 0.6–28.3 μm ([[orange (colour)|orange]] to mid-[[infrared]])

| instruments_list = {{Infobox spaceflight/Instruments
| acronym1 = NIRCam
| name1 = [[NIRCam|Near IR Camera]]
| acronym2 = NIRSpec
| name2 = [[NIRSpec (Near-Infrared Spectrograph)|Near-Infrared Spectrograph]]
| acronym3 = MIRI
| name3 = [[MIRI (Mid-Infrared Instrument)|Mid IR Instrument]]
| acronym4 = NIRISS
| name4 = [[Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph|Near Infrared Imager and Slitless Spectrograph]]
| acronym5 = FGS
| name5 = [[Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph|Fine Guidance Sensor]] 
'''Elements:'''
* [[Integrated Science Instrument Module]]
* [[Optical Telescope Element]]
* Spacecraft Element ([[Spacecraft Bus (JWST)|Spacecraft Bus]] and [[Sunshield (JWST)|Sunshield]])
}}

| trans_band = {{ubl
| [[S band|S-band]], telemetry, tracking, and control
| [[Ka band|Ka-band]], data acquisition
}}
| trans_bandwidth = {{ubli
| S-band up: 16 kbit/s
| S-band down: 40 kbit/s
| Ka-band down: up to 28 Mbit/s
}}

| insignia = James Webb Space Telescope Launch insignia.png
| insignia_caption = James Webb Space Telescope mission patch
| insignia_alt = JWST logo
| insignia_size = 200px
}}

The '''James Webb Space Telescope''' ('''JWST''') is a [[space telescope]] being jointly developed by [[NASA]], the [[European Space Agency]] (ESA), and the [[Canadian Space Agency]] (CSA). It is planned to succeed the [[Hubble Space Telescope]] as NASA's [[Large strategic science missions|flagship]] [[astrophysics]] mission.<ref name="about">{{cite web|url=https://jwst.nasa.gov/about.html|title=About the James Webb Space Telescope|access-date=13 January 2012}} {{PD-notice}}</ref><ref>{{cite web|url=https://jwst.nasa.gov/comparison.html|title=How does the Webb Contrast with Hubble?|publisher=NASA|access-date=4 December 2016|url-status=dead|archive-url=https://web.archive.org/web/20161203014957/http://jwst.nasa.gov/comparison.html|archive-date=3 December 2016}} {{PD-notice}}</ref> JWST is scheduled to be launched no earlier than Friday 24 December 2021 during [[Ariane flight VA256]]. It will provide improved infrared resolution and sensitivity over Hubble, and will enable a broad range of investigations across the fields of [[astronomy]] and [[cosmology]], including observing some of the most distant events and objects in the [[universe]], such as the [[Galaxy formation and evolution|formation of the first galaxies]], and detailed atmospheric characterization of [[Habitable exoplanet|potentially habitable exoplanets]].

The [[primary mirror]] of JWST, the [[Optical Telescope Element]], consists of 18 hexagonal [[Segmented mirror|mirror segments]] made of [[gold]]-plated [[beryllium]] which combine to create a {{cvt|6.5|m}} diameter mirror {{mdash}} considerably larger than Hubble's {{cvt|2.4|m}} mirror. Unlike the Hubble telescope, which observes in the [[Ultraviolet|near ultraviolet]], [[visible spectrum|visible]], and [[Infrared|near infrared]] (0.1 to 1 μm) spectra, JWST will observe in a lower frequency range, from long-wavelength visible light through [[infrared|mid-infrared]] (0.6 to 28.3 μm), which will allow it to observe high [[redshift]] objects that are too old and too distant for Hubble to observe.<ref name="ReferenceB">{{cite web|url=http://www.stsci.edu/jwst/overview/history/1994|archive-url=https://wayback.archive-it.org/all/20140203162406/http://www.stsci.edu/jwst/overview/history/1994|url-status=dead|archive-date=3 February 2014|title=James Webb Space Telescope JWST History: 1989-1994 |publisher=Space Telescope Science Institute, Baltimore, Maryland|date=2017|access-date=29 December 2018}}</ref><ref>{{cite web|url=http://www.stsci.edu/jwst/instrumentation|title=Instrumentation of JWST |date=29 January 2020|publisher=Space Telescope Science Institute|access-date=29 January 2020}}</ref> The telescope must be kept very cold in order to observe in the infrared without interference, so it will be deployed in space near the Sun–Earth {{L2}} [[Lagrange point]] (which is 0.010 [[astronomical unit|au]] – or 3.9 times the [[Lunar distance (astronomy)|Lunar distance]] – away from [[Earth]])<ref>{{cite web |url=https://www.esa.int/Science_Exploration/Space_Science/Herschel/L2_the_second_Lagrangian_Point |title=L2, the second Lagrangian Point |access-date=5 December 2021}}</ref> and a large [[Sunshield (JWST)|sunshield]] made of [[silicon]]- and [[Aluminium|aluminum]]-coated [[Kapton]] will keep its [[cold mirror|mirror]] and instruments below {{cvt|50|K|0}}.<ref name="nasasunshield"/>

The NASA [[Goddard Space Flight Center]] (GSFC) is managing the development effort, and the [[Space Telescope Science Institute]] will operate Webb after launch.<ref>{{cite web |url=https://www.jwst.nasa.gov/content/about/index.html|title=About Webb|publisher=NASA|date=2019|access-date=4 June 2021}} {{PD-notice}}</ref> The prime contractor is [[Northrop Grumman]].<ref>{{cite web |date=2017|title=James Webb Space Telescope|url=http://www.northropgrumman.com/Capabilities/JWST/Pages/default.aspx|access-date=31 January 2017|publisher=Northrop Grumman}}</ref> It is named for [[James E. Webb]],<ref name="NAT-20210-723">{{cite journal|last=Witze|first=Alexndra|title=NASA investigates renaming James Webb telescope after anti-LGBT+ claims—Some astronomers argue the flagship observatory—successor to the Hubble Space Telescope—will memorialize discrimination. Others are waiting for more evidence.|url=https://www.nature.com/articles/d41586-021-02010-x|date=23 July 2021|journal=Nature|volume=596 |issue=7870|pages=15–16|doi=10.1038/d41586-021-02010-x|pmid=34302150|s2cid=236212498|access-date=23 July 2021}}</ref> who was the [[List of administrators and deputy administrators of NASA|administrator of NASA]] from 1961 to 1968 and played an integral role in the [[Apollo program]].<ref>{{cite web|url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=33148|archive-url=https://web.archive.org/web/20030821120829/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=33148|url-status=dead|archive-date=21 August 2003|title=ESA JWST Timeline|access-date=13 January 2012}} {{PD-notice}}</ref><ref name="jwst NASA">{{cite web|last=During|first=John|title=The James Webb Space Telescope|url=https://www.jwst.nasa.gov/|publisher=NASA|access-date=31 December 2011}} {{PD-notice}}</ref>

Development began in 1996 for a launch that was initially planned for 2007 and a US$500 million budget,<ref name="stsci1996"/> but the project had numerous delays and cost overruns and underwent a major redesign in 2005.<ref name="replan"/> Construction was completed in late 2016, after which its extensive testing phase began.<ref name="sd12-16">{{cite web |url=http://www.spacedaily.com/reports/James_Webb_Space_Telescope_observatory_is_assembled_999.html|title=James Webb Space Telescope observatory is assembled|publisher=Space Daily|date=29 December 2016|access-date=3 February 2017}}</ref><ref name="snews12-16">{{cite web|url=http://spacenews.com/no-damage-to-jwst-after-vibration-test-anomaly/|title=No damage to JWST after vibration test anomaly|author=Foust, Jeff |publisher=SpaceNews|date=23 December 2016|access-date=3 February 2017}}</ref> In March 2018, NASA further delayed the launch after the telescope's sunshield ripped during a practice deployment.<ref name="NYT-27 March 2018">{{cite news|last1=Overbye|first1=Dennis|title=NASA's Webb Telescope Faces More Setbacks|url=https://www.nytimes.com/2018/03/27/science/nasa-webb-telescope.html|access-date=5 April 2018 |newspaper=The New York Times|date=27 March 2018}}</ref> Launch was delayed again in June 2018 following recommendations from an independent review board.<ref name="bridenstine-launch">{{cite tweet |user=JimBridenstine|number=1012008010150006786|title=The James Webb Space Telescope will produce first of its kind, world-class science. Based on recommendations by an Independent Review Board, the new launch date for Webb is 30 March 2021. I'm looking forward to the launch of this historic mission|date=27 June 2018|access-date=27 June 2018}} {{PD-notice}}</ref><ref name="NASAJWSTdelay2021">{{cite news|title=NASA Completes Webb Telescope Review, Commits to Launch in Early 2021|url=https://www.nasa.gov/press-release/nasa-completes-webb-telescope-review-commits-to-launch-in-early-2021|access-date=27 June 2018 |publisher=NASA|date=27 June 2018}} {{PD-notice}}</ref><ref name="WP-20180724">{{cite news|last1=Kaplan|first1=Sarah|last2=Achenbach|first2=Joel|title=NASA's next great space telescope is stuck on Earth after screwy errors|url=https://www.washingtonpost.com/national/health-science/nasas-next-great-space-telescope-is-stuck-on-earth-after-screwy-errors/2018/07/24/742f17d4-8e93-11e8-8322-b5482bf5e0f5_story.html|date=24 July 2018|newspaper=The Washington Post|access-date=25 July 2018}}</ref> Work on integration and testing of the telescope was suspended in March 2020 due to the [[COVID-19 pandemic]],<ref name="cvdly">{{cite news|url=https://spacenews.com/coronavirus-pauses-work-on-jwst/|title=Coronavirus pauses work on JWST|date=March 20, 2020|first=Jeff|last=Foust|publisher=SpaceNews}}</ref> adding further delays. Following work resumption, the launch date was delayed to 31 October 2021.<ref name="NASA-20200716">{{cite web|url=https://www.esa.int/Science_Exploration/Space_Science/James_Webb_Space_Telescope_to_launch_in_October_2021 |title=NASA Announces New James Webb Space Telescope Target Launch Date}} {{PD notice}}</ref><ref name="NYT-20200716">{{cite news|url=https://www.nytimes.com/2020/07/16/science/nasa-james-webb-space-telescope-delay.html|title=NASA Delays James Webb Telescope Launch Date, Again – The universe will have to wait a little longer|last=Overbye|first=Dennis|date=16 July 2020|newspaper=The New York Times|access-date=17 July 2020}}</ref> Problems with the [[Ariane 5]] launch vehicle and the telescope itself subsequently pushed the launch date to 22 December 2021.<ref name="ars-20210601">{{cite web|last=Berger|first=Eric |url=https://arstechnica.com/science/2021/06/webb-telescope-launch-date-slips-again/|title=Webb telescope launch date slips again|publisher=Ars Technica|date=1 June 2021|access-date=1 June 2021}}</ref><ref>{{cite news|url=https://spacenews.com/ariane-5-issue-could-delay-jwst/|title=Ariane 5 issue could delay JWST|last=Foust|first=Jeff|date=12 May 2021|publisher=SpaceNews|access-date=13 May 2021}}</ref><ref name="esa-dec">{{cite web|url=https://www.esa.int/Science_Exploration/Space_Science/Webb/Update_on_Webb_telescope_launch|title=Update on Webb telescope launch|publisher=ESA|date=22 November 2021|access-date=22 November 2021}}</ref>

On being mounted on the launch vehicle, a communication problem between the telescope and the launch vehicle led to a further delay to "no earlier than 24 December 2021".<ref name="24dec"/> Concerns among the involved scientists and engineers about the launch and deployment of the telescope have been well described.<ref name="NYT-20211214">{{cite news|last=Overbye|first=Dennis|authorlink=Dennis Overbye|title=Why the World's Astronomers Are Very, Very Anxious Right Now - The James Webb Space Telescope is endowed with the hopes and trepidations of a generation of astronomers + Comment |url=https://www.nytimes.com/2021/12/14/science/james-webb-telescope-launch.html#permid=115929090|date=14 December 2021|newspaper=The New York Times|access-date=15 December 2021}}</ref>

== Features ==
[[File:Atmospheric electromagnetic opacity.svg|thumb|upright=1.0|left|Rough plot of Earth's atmospheric [[transmittance]] (or opacity) to various wavelengths of electromagnetic radiation, including [[visible light]]]]
[[File:JWST launch configuration.png|thumb|upright=1.0|right|Launch configuration of JWST in an [[Ariane 5]]]]

The James Webb Space Telescope has an expected mass about half of [[Hubble Space Telescope]]'s, but its [[primary mirror]], a {{cvt|6.5|m}} diameter gold-coated beryllium reflector will have a collecting area over six times as large, {{cvt|25.4|m2}}, using 18 hexagonal mirrors with {{cvt|0.9|m2}} obscuration for the secondary support struts.<ref>{{cite journal|arxiv=1203.0002|doi=10.1117/1.OE.51.1.011011 |title=Experience with the Hubble Space Telescope: 20 years of an archetype|year=2012|last1=Lallo|first1=Matthew D.|s2cid=15722152|journal=Optical Engineering|volume=51|issue=1|pages=011011–011011–19 |bibcode=2012OptEn..51a1011L}}</ref>

JWST is designed primarily for [[Infrared astronomy|near-infrared astronomy]], but can also see orange and red visible light, as well as the mid-infrared region, depending on the instrument. The design emphasizes the near to mid-infrared for three main reasons:

* high-[[redshift]] objects have their visible emissions shifted into the infrared
* cold objects such as [[debris disk]]s and planets emit most strongly in the infrared
* this band is difficult to study from the ground or by existing space telescopes such as Hubble

Ground-based telescopes must look through Earth's atmosphere, which is opaque in many infrared bands (see figure of [[Atmosphere of Earth#Absorption|atmospheric absorption]]). Even where the atmosphere is transparent, many of the target chemical compounds, such as water, carbon dioxide, and methane, also exist in the [[Atmosphere of Earth|Earth's atmosphere]], vastly complicating analysis. Existing space telescopes such as Hubble cannot study these bands since their mirrors are insufficiently cool (the Hubble mirror is maintained at about {{cvt|15|C|K F|0}}) thus the telescope itself radiates strongly in the infrared bands.<ref name="ipac.caltech.edu"/>

JWST will operate near the Earth–Sun [[Lagrange point|L2 (Lagrange point)]], approximately {{cvt|1500000|km}} beyond Earth's orbit. By way of comparison, Hubble orbits {{cvt|550|km}} above Earth's surface, and the Moon is roughly {{cvt|400000|km}} from Earth. This distance made post-launch repair or upgrade of JWST hardware virtually impossible with the spaceships available during the telescope design and fabrication stage. Objects near this Lagrange point can orbit the Sun in synchrony with the Earth, allowing the telescope to remain at a roughly constant distance<ref name="stsci.edu">{{cite web |url=http://www.stsci.edu/jwst/overview/design/orbit|archive-url=https://wayback.archive-it.org/all/20140203174537/http://www.stsci.edu/jwst/overview/design/orbit|url-status=dead|archive-date=3 February 2014 |title=L2 Orbit|publisher=Space Telescope Science Institute|access-date=28 August 2016}}</ref> and with constant orientation of the single heatshield and the [[Spacecraft Bus (JWST)|Bus]] toward the earth and the sun to block heat and light from the Sun and Earth and maintain communications. This arrangement will keep the temperature of the spacecraft below {{cvt|50|K|0}}, necessary for infrared observations.<ref name=nasasunshield>{{cite web|title=The Sunshield|url=http://www.jwst.nasa.gov/sunshield.html|website=nasa.gov |publisher=NASA|access-date=28 August 2016}} {{PD-notice}}</ref><ref>{{cite web|url=http://news.nationalgeographic.com/2015/04/150423-hubble-anniversary-webb-telescope-space|title=Hubble Still Wows At 25, But Wait Till You See What's Next|publisher=National Geographic|author=Drake, Nadia|date=24 April 2015}}</ref>

<gallery align="center" mode="packed" heights="300px">
File:James Webb Space Telescope 2009 top.jpg|Three-quarter view of the top
File:James Webb Space Telescope 2009 bottom.jpg|Bottom (Sun-facing side)
</gallery>

=== Sunshield protection ===
{{Main|Sunshield (JWST)}}
[[File:James Webb telescope sunshield.jpg|thumb|upright=1.0|right|Test unit of the sunshield stacked and expanded at the [[Northrop Grumman]] facility in California, 2014]]

To make observations in the [[Infrared|infrared spectrum]], JWST must be kept under {{cvt|50|K}}; otherwise, infrared radiation from the telescope itself would overwhelm its instruments. It therefore uses a large sunshield to block light and heat from the [[Sun]], [[Earth]], and [[Moon]], and its position near the Earth–Sun [[Lagrange point|L2 point]] keeps all three bodies on the same side of the spacecraft at all times.<ref>{{cite web|url=http://jwst.nasa.gov/orbit.html|title=The James Webb Space Telescope|website=nasa.gov|access-date=28 August 2016}} {{PD-notice}}</ref> Its halo orbit around the [[Lagrange point|L2 point]] avoids the shadow of the Earth and Moon, maintaining a constant environment for the sunshield and solar arrays.<ref name="stsci.edu"/> The shielding maintains a stable temperature for the structures on the dark side, which is critical to maintaining precise alignment of the primary mirror segments.{{citation needed|date=April 2019}}

The five-layer sunshield, each layer as thin as a human hair,<ref>{{cite web|url=https://www.jwst.nasa.gov/content/about/innovations/coating.html|title=Sunshield Coatings Webb/NASA|website=jwst.nasa.gov |access-date=2020-05-03}} {{PD-notice}}</ref> is constructed from [[Kapton|Kapton E]], a commercially available [[polyimide]] film from [[DuPont]], with membranes specially coated with aluminum on both sides and doped [[silicon]] on the Sun-facing side of the two hottest layers to reflect the Sun's heat back into space.<ref>{{cite web|url=https://jwst.nasa.gov/sunshield.html|website=NASA Goddard Space Flight Center |title=The Sunshield|publisher=NASA|access-date=5 June 2018}} {{PD-notice}}</ref> Accidental tears of the delicate film structure during testing in 2018 were among the factors delaying the project.<ref>{{cite web|url=http://www.sciencemag.org/news/2018/03/nasa-announces-more-delays-giant-space-telescope|title=NASA announces more delays for giant space telescope|website=sciencemag.org|date=27 March 2018|access-date=5 June 2018}}</ref>

The sunshield is designed to be folded twelve times so that it will fit within the [[Ariane 5]] rocket's payload fairing, which is {{cvt|4.57|m|ft}} in diameter, and {{cvt|16.19|m|ft}} long. Once deployed at the L2 point, it will unfold to {{cvt|14.162|x|21.197|m}}. The sunshield was hand-assembled at [[ManTech International|ManTech (NeXolve)]] in [[Huntsville, Alabama]], before it was delivered to [[Northrop Grumman]] in [[Redondo Beach, California]], for testing.<ref>Morring, Jr., Frank, Sunshield [[Aviation Week and Space Technology]] 16 December 2013, pp. 48-49</ref>

=== Optics ===
{{Main|Optical Telescope Element}}
[[File:Engineers Clean JWST Secondary Reflector with Carbon Dioxide Snow.jpg|thumb|upright=1.0|right|Engineers [[Carbon dioxide cleaning|cleaning a test mirror with carbon dioxide snow]], 2015]]
[[File:James Webb Space Telescope Revealed (26832090085).jpg|thumb|upright=1.0|right|Main mirror assembled at [[Goddard Space Flight Center]], May 2016]]

JWST's [[primary mirror]] is a {{cvt|6.5|m}}-diameter gold-coated beryllium reflector with a collecting area of {{cvt|25.4|m2}}. If it were built as a single large mirror, this would have been too large for existing launch vehicles. The mirror is therefore composed of 18 hexagonal segments which will unfold after the telescope is launched. Image plane [[Wave-front sensing|wavefront sensing]] through [[Gerchberg–Saxton algorithm|phase retrieval]] will be used to position the [[mirror segment]]s in the correct location using very precise micro-motors. Subsequent to this initial configuration, they will only need occasional updates every few days to retain optimal focus.<ref>{{cite web|url=http://www.stsci.edu/jwst/ote/wavefront-sensing-and-control|archive-url=https://archive.today/20120805213402/http://www.stsci.edu/jwst/ote/wavefront-sensing-and-control|url-status=dead|archive-date=5 August 2012|title=JWST Wavefront Sensing and Control|publisher=Space Telescope Science Institute|access-date=9 June 2011}}</ref> This is unlike terrestrial telescopes, for example the [[W. M. Keck Observatory|Keck telescopes]], which continually adjust their mirror segments using [[active optics]] to overcome the effects of gravitational and wind loading. The Webb telescope will use 126 small motors to occasionally adjust the optics as there is a lack of environmental disturbances of a telescope in space.<ref name="wired-20191022">{{cite magazine|last=Mallonee|first=Laura|url=https://www.wired.com/story/nasas-biggest-telescope-ever-prepares-2021-launch/|title=NASA's Biggest Telescope Ever Prepares for a 2021 Launch|magazine=9 |access-date=4 June 2021 |url-access=limited}}</ref>

JWST's optical design is a [[three-mirror anastigmat]],<ref>{{cite web|url=http://www.stsci.edu/jwst/ote/mirrors|archive-url=https://archive.today/20120805184514/http://www.stsci.edu/jwst/ote/mirrors|url-status=dead|archive-date=5 August 2012|title=JWST Mirrors|publisher=Space Telescope Science Institute|access-date=9 June 2011}}</ref> which makes use of curved secondary and tertiary mirrors to deliver images that are free of [[optical aberrations]] over a wide field. In addition, there is a fine steering mirror which can adjust its position many times per second to provide [[image stabilization]].

[[Ball Aerospace & Technologies]] is the principal optical subcontractor for the JWST project, led by prime contractor [[Northrop Grumman|Northrop Grumman Aerospace Systems]], under a contract from the NASA [[Goddard Space Flight Center]], in [[Greenbelt, Maryland]].<ref name=howBig/><ref>{{cite web|url=https://www.nasa.gov/feature/goddard/2016/science-instruments-of-nasa-s-james-webb-space-telescope-successfully-installed|title=Science Instruments of NASA's James Webb Space Telescope Successfully Installed|publisher=NASA|date=24 May 2016|access-date=2 February 2017}} {{PD-notice}}</ref> Eighteen primary mirror segments, secondary, tertiary and fine steering mirrors, plus [[flight spare]]s have been fabricated and polished by Ball Aerospace & Technologies based on beryllium segment blanks manufactured by several companies including Axsys, [[Materion|Brush Wellman]], and Tinsley Laboratories.{{citation needed|date=April 2019}}

The final segment of the primary mirror was installed on 3 February 2016,<ref>{{cite web|url=https://www.nasa.gov/press-release/nasas-james-webb-space-telescope-primary-mirror-fully-assembled/|publisher=NASA| title=NASA's James Webb Space Telescope Primary Mirror Fully Assembled|access-date=23 March 2016|date=4 February 2016}} {{PD-notice}}</ref> and the secondary mirror was installed on 3 March 2016.<ref>{{cite web |url=https://www.nasa.gov/feature/goddard/2016/nasas-james-webb-space-telescope-secondary-mirror-installed/|publisher=NASA|title=NASA's James Webb Space Telescope Secondary Mirror Installed|access-date=23 March 2016|date=7 March 2016}} {{PD-notice}}</ref>

=== Scientific instruments ===
[[File:Nircam modules.jpg|thumb|upright=1.0|right|NIRCam model]]
[[File:NIRSpec Astrium.jpg|thumb|upright=1.0|right|NIRSpec model]]
[[File:JWST MIRI model.jpg|thumb|upright=1.0|right|MIRI 1:3 scale model]]

The [[Integrated Science Instrument Module]] (ISIM) is a framework that provides electrical power, computing resources, cooling capability as well as structural stability to the Webb telescope. It is made with bonded graphite-epoxy composite attached to the underside of Webb's telescope structure. The ISIM holds the four science instruments and a guide camera.<ref name=isim/>

* [[NIRCam]] (Near InfraRed Camera) is an [[Thermographic camera|infrared imager]] which will have a spectral coverage ranging from the edge of the visible (0.6 micrometers) through the near infrared (5 micrometers).<ref>{{cite web|url=http://www.stsci.edu/jwst/instruments/nircam/|archive-url=https://www.webcitation.org/6FHXODFHR?url=http://www.stsci.edu/jwst/instruments/nircam/|url-status=dead|archive-date=21 March 2013|title=James Webb Space Telescope Near Infrared Camera|publisher=STScI|access-date=24 October 2013}}</ref><ref>{{cite web|url=http://ircamera.as.arizona.edu/nircam/|title=NIRCam for the James Webb Space Telescope|publisher=University of Arizona|access-date=24 October 2013}}</ref> There are 10 sensors each of 4 megapixels. NIRCam will also serve as the observatory's wavefront sensor, which is required for wavefront sensing and control activities. NIRCam was built by a team led by the [[University of Arizona]], with principal investigator [[Marcia J. Rieke]]. The industrial partner is Lockheed-Martin's Advanced Technology Center located in [[Palo Alto, California]].<ref name="WhoDoesWhatWeb">{{cite web|url=http://www.stsci.edu/jwst/overview/status.html|archive-url=http://arquivo.pt/wayback/20090715053935/http://www.stsci.edu/jwst/overview/status.html |url-status=dead|archive-date=15 July 2009 |title=JWST Current Status|publisher=STScI|access-date=5 July 2008}}</ref>
* [[NIRSpec]] (Near InfraRed Spectrograph) will also perform [[spectroscopy]] over the same wavelength range. It was built by the European Space Agency at [[ESTEC]] in [[Noordwijk]], Netherlands. The leading development team includes members from [[Airbus Defence and Space]], Ottobrunn and Friedrichshafen, Germany, and the [[Goddard Space Flight Center]]; with Pierre Ferruit ([[École normale supérieure de Lyon]]) as NIRSpec project scientist. The NIRSpec design provides three observing modes: a low-resolution mode using a prism, an R~1000 multi-object mode, and an R~2700 integral field unit or long-slit spectroscopy mode.<ref name="nirspec">{{cite web|url=http://sci.esa.int/jwst/45694-nirspec-the-near-infrared-spectrograph/|title=NIRSpec – the near-infrared spectrograph on JWST|publisher=European Space Agency |date=22 February 2015|access-date=2 February 2017}}</ref> Switching of the modes is done by operating a wavelength preselection mechanism called the Filter Wheel Assembly, and selecting a corresponding dispersive element (prism or grating) using the Grating Wheel Assembly mechanism.<ref name=nirspec/> Both mechanisms are based on the successful ISOPHOT wheel mechanisms of the [[Infrared Space Observatory]]. The multi-object mode relies on a complex micro-shutter mechanism to allow for simultaneous observations of hundreds of individual objects anywhere in NIRSpec's field of view. There are two sensors each of 4 megapixels. The mechanisms and their optical elements were designed, integrated and tested by [[Carl Zeiss AG|Carl Zeiss]] Optronics GmbH of Oberkochen, Germany, under contract from [[Astrium]].<ref name=nirspec/>
* [[MIRI (Mid-Infrared Instrument)|MIRI]] (Mid-InfraRed Instrument) will measure the mid-to-long-infrared wavelength range from 5 to 27 micrometers.<ref name=miri/><ref name="nasamiri">{{cite web |url=https://jwst.nasa.gov/miri.html|title=JWST: Mid-Infrared Instrument (MIRI)|publisher=NASA|date=2017|access-date=3 February 2017}} {{PD-notice}}</ref> It contains both a [[thermal camera|mid-infrared camera]] and an imaging [[spectrometer]].<ref name=howBig/> MIRI was developed as a collaboration between NASA and a consortium of European countries, and is led by [[George H. Rieke|George Rieke]] ([[University of Arizona]]) and [[Gillian Wright (astronomer)|Gillian Wright]] ([[UK Astronomy Technology Centre]], [[Edinburgh]], Scotland, part of the [[Science and Technology Facilities Council]] (STFC)).<ref name="WhoDoesWhatWeb"/> MIRI features similar wheel mechanisms to NIRSpec which are also developed and built by Carl Zeiss Optronics GmbH under contract from the [[Max Planck Institute for Astronomy]], [[Heidelberg]], Germany. The completed Optical Bench Assembly of MIRI was delivered to Goddard Space Flight Center in mid-2012 for eventual integration into the ISIM. The temperature of the MIRI must not exceed 6 [[kelvin]]s (K): a helium gas mechanical cooler sited on the warm side of the environmental shield provides this cooling.<ref name="miricooler">{{cite journal |url=http://ircamera.as.arizona.edu/MIRI/miricooler.pdf|title=James Webb Space Telescope Mid-Infrared Instrument Cooler systems engineering|last1=Banks|first1=Kimberly|last2=Larson|first2=Melora|last3=Aymergen |first3=Cagatay|last4=Zhang|first4=Burt|s2cid=17507846|editor2-first=Martin J.|editor2-last=Cullum|editor1-first=George Z.|editor1-last=Angeli|journal=Proceedings of SPIE|volume=7017|page=5|quote=Fig. 1. Cooler Architecture Overview|access-date=6 February 2016|bibcode=2008SPIE.7017E..0AB|year=2008|doi=10.1117/12.791925|series=Modeling, Systems Engineering, and Project Management for Astronomy III}}</ref>
* FGS/NIRISS ([[Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph]]), led by the [[Canadian Space Agency]] under project scientist John Hutchings ([[Herzberg Institute of Astrophysics]], [[National Research Council (Canada)]]), is used to stabilize the line-of-sight of the observatory during science observations. Measurements by the FGS are used both to control the overall orientation of the spacecraft and to drive the fine steering mirror for image stabilization. The Canadian Space Agency is also providing a Near Infrared Imager and Slitless Spectrograph (NIRISS) module for astronomical imaging and spectroscopy in the 0.8 to 5 micrometre wavelength range, led by principal investigator René Doyon at the [[Université de Montréal]].<ref name="WhoDoesWhatWeb"/> Because the NIRISS is physically mounted together with the FGS, they are often referred to as a single unit; however, they serve entirely different purposes, with one being a scientific instrument and the other being a part of the observatory's support infrastructure.

NIRCam and MIRI feature starlight-blocking [[coronagraph]]s for observation of faint targets such as [[extrasolar planets]] and [[circumstellar disks]] very close to bright stars.<ref name=nasamiri/>

The infrared detectors for the NIRCam, NIRSpec, FGS, and NIRISS modules are being provided by Teledyne Imaging Sensors (formerly Rockwell Scientific Company). The James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) and Command and Data Handling (ICDH) engineering team uses [[SpaceWire]] to send data between the science instruments and the data-handling equipment.<ref>
[http://www.nasa.gov/vision/universe/watchtheskies/jwst_spacewired_prt.htm "NASA's James Webb Space Telescope Gets 'Spacewired'"] 2007 {{PD-notice}}</ref>

=== Spacecraft Bus ===
{{Main|Spacecraft Bus (JWST)}}
[[File:SpacecraftBus-model.jpg|thumb|upright=1.0|right|Diagram of the Spacecraft Bus. The solar panel is in green and the light purple panels are radiators.]]

The [[Spacecraft Bus (JWST)|Spacecraft Bus]] is the primary support component of the James Webb Space Telescope, that hosts a multitude of computing, communication, propulsion, and structural parts, bringing the different parts of the telescope together.<ref name="jwstbus">{{cite web|url=http://jwst.nasa.gov/bus.html|title=The Spacecraft Bus|publisher=NASA James Webb Space Telescope|date=2017}} {{PD-notice}}</ref> Along with the sunshield, it forms the spacecraft element of the [[space telescope]].<ref name="observ">{{cite web|url=http://jwst.nasa.gov/observatory.html|title=The JWST Observatory|publisher=NASA|date=2017|quote=The Observatory is the space-based portion of the James Webb Space Telescope system and is {{sic|comprised|hide=y|of}} three elements: the Integrated Science Instrument Module (ISIM), the Optical Telescope Element (OTE), which includes the mirrors and backplane, and the Spacecraft Element, which includes the spacecraft bus and the sunshield}} {{PD-notice}}</ref> The other two major elements of JWST are the [[Integrated Science Instrument Module]] (ISIM) and the [[Optical Telescope Element]] (OTE).<ref name=isimnasa>{{cite web |url=http://jwst.nasa.gov/isim.html|title=Integrated Science Instrument Module (ISIM)|publisher=NASA James Webb Space Telescope|date=2017|access-date=30 November 2016|archive-date=3 December 2016|archive-url=https://web.archive.org/web/20161203070235/http://jwst.nasa.gov/isim.html|url-status=dead}} {{PD-notice}}</ref> Region 3 of ISIM is also inside the ''Spacecraft Bus''; region 3 includes ISIM Command and Data Handling subsystem and the MIRI [[cryocooler]].<ref name="isimnasa"/> The Spacecraft Bus is connected to Optical Telescope Element via the Deployable Tower Assembly, which also connects to the sunshield.<ref name=jwstbus/> The Spacecraft Bus is on the Sun-facing "warm" side of the sunshield and operates at a temperature of about {{cvt|300|K|C F}}.<ref name=observ/>

The structure of the Spacecraft Bus weighs {{cvt|350|kg}}, and must support the {{cvt|6200|kg}} space telescope.<ref name="facts">{{cite web|url=https://jwst.nasa.gov/facts.html|title=JWST vital facts: mission goals|publisher=NASA James Webb Space Telescope|date=2017|access-date=29 January 2017}} {{PD-notice}}</ref> It is made primarily of graphite composite material.<ref name=facts/> It was assembled in [[California]], assembly was completed in 2015, and then it had to be integrated with the rest of the space telescope leading up to its planned 2021 launch. The spacecraft bus can rotate the telescope with a pointing precision of one [[Minute and second of arc|arcsecond]], and isolates vibration down to two milliarcseconds.<ref>{{cite web|url=http://www.compositesworld.com/news/james-webb-space-telescope-spacecraft-inches-towards-full-assembly|title=James Webb Space Telescope spacecraft inches towards full assembly|publisher=Composites World|author=Sloan, Jeff|date=12 October 2015}}</ref>

In the central computing, memory storage, and communications equipment,<ref name=jwstbus/> the processor and software direct data to and from the instruments, to the solid-state memory core, and to the radio system which can send data back to Earth and receive commands.<ref name=jwstbus/> The computer also controls the pointing of the spacecraft, taking in sensor data from the gyroscopes and [[star tracker]], and sending commands to the reaction wheels or thrusters.<ref name=jwstbus/>

The spacecraft has 10 pairs of thrusters, each pair consisting of one primary and a redundant back up. The thrusters use [[hydrazine]] fuel (159 liters at launch) and [[dinitrogen tetroxide]] as oxidizer (79.5 liters at launch).<ref>{{cite web|last=Clark|first=Stephen|date=November 28, 2021|title=NASA gives green light to fuel James Webb Space Telescope|url=https://spaceflightnow.com/2021/11/28/nasa-gives-green-light-to-fuel-james-webb-space-telescope/|publisher=Spaceflight Now}}</ref>

== Comparison with other telescopes ==
[[File:JWST-HST-primary-mirrors.svg|thumb|upright=1.0|right|Comparison with Hubble primary mirror]]
[[File:SAFIR-CALISTO.jpg|thumb|upright=1.0|right|Calisto architecture for SAFIR would be a successor to Spitzer, requiring greater passive cooling than JWST (5 Kelvin).<ref>{{cite web |url=http://safir.jpl.nasa.gov/whatIs.shtml|title=What is SAFIR?|publisher=NASA, Jet Propulsion Laboratory, Goddard Flight Center, California Institute of Technology|access-date=14 July 2013|archive-url=https://web.archive.org/web/20130216131018/http://safir.jpl.nasa.gov/whatIs.shtml|archive-date=16 February 2013|url-status=dead}} {{PD-notice}}</ref>]]

The desire for a large infrared space telescope traces back decades. In the United States, the Shuttle Infrared Telescope Facility (SIRTF) was planned while the Space Shuttle was in development, and the potential for infrared astronomy was acknowledged at that time.<ref name="proceedings.spiedigitallibrary.org">{{cite conference|url=http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1227080 |conference=1978 Los Angeles Technical Symposium|publisher=Society of Photographic Instrumentation Engineers|title=Infrared Detector Performance In The Shuttle Infrared Telescope Facility (SIRTF) |vauthors=McCarthy SG, Autio GW|doi=10.1117/12.956060|volume=81|issue=6 June|pages=81–88|year=1978|series=Utilization of Infrared Detectors|bibcode=1978SPIE..132...81M}}</ref> Compared to ground telescopes, space observatories were free from atmospheric absorption of infrared light. Space observatories opened up a whole "new sky" for astronomers.<ref name="proceedings.spiedigitallibrary.org"/>

{{Blockquote|The tenuous atmosphere above the 400 km nominal flight altitude has no measurable absorption so that detectors operating at all wavelengths from 5 μm to 1000 μm can achieve high radiometric sensitivity.|S. G. McCarthy and G. W. Autio, 1978.<ref name="proceedings.spiedigitallibrary.org"/>}}

However, infrared telescopes have a disadvantage: they need to stay extremely cold, and the longer the wavelength of infrared, the colder they need to be.<ref name="ipac.caltech.edu">{{cite web |url=http://www.ipac.caltech.edu/outreach/Edu/orbit.html|title=Infrared astronomy from earth orbit|publisher=Infrared Processing and Analysis Center, NASA Spitzer Science Center, California Institute of Technology|date=2017|url-status=dead|archive-url=https://web.archive.org/web/20161221020839/http://www.ipac.caltech.edu/outreach/Edu/orbit.html|archive-date=21 December 2016}} {{PD-notice}}</ref> If not, the background heat of the device itself overwhelms the detectors, making it effectively blind.<ref name="ipac.caltech.edu"/> This can be overcome by careful spacecraft design, in particular by placing the telescope in a [[Cryogenic storage dewar|dewar]] with an extremely cold substance, such as [[liquid helium]].<ref name="ipac.caltech.edu"/> This has meant most infrared telescopes have a lifespan limited by their coolant, as short as a few months, maybe a few years at most.<ref name="ipac.caltech.edu"/>

In some cases, it has been possible to maintain a temperature low enough through the design of the spacecraft to enable near-infrared observations without a supply of coolant, such as the extended missions of [[Spitzer Space Telescope]] and [[Wide-field Infrared Survey Explorer]]. Another example is Hubble's [[Near Infrared Camera and Multi-Object Spectrometer]] (NICMOS) instrument, which started out using a block of [[Solid nitrogen|nitrogen ice]] that depleted after a couple of years, but was then converted to a [[cryocooler]] that worked continuously. The James Webb Space Telescope is designed to cool itself without a dewar, using a combination of sunshields and radiators, with the mid-infrared instrument using an additional cryocooler.<ref>{{cite web|url=https://phys.org/news/2016-06-cold-cooler-nasa-telescope.html |title=How cold can you go? Cooler tested for NASA telescope|publisher=Phys.org|date=14 June 2016|access-date=31 January 2017}}</ref>

[[File:2294 Mission Posters Webb English-1200.jpg|thumb|upright=1.0|right|James Webb Space Telescope Official Poster]]

{| class=wikitable style="float:center; margin:10px; text-align:center;"
|-
|+ Selected space telescopes and instruments<ref>{{cite web|url=http://herschel.jpl.nasa.gov/relatedMissions.shtml|title=JPL: Herschel Space Observatory: Related Missions|publisher=NASA, Jet Propulsion Laboratory, Goddard Flight Center, California Institute of Technology|access-date=4 June 2012}} {{PD-notice}}</ref>
|-
! Name
! Year !! [[Electromagnetic spectrum|Wavelength]] (μm) !! Aperture (m)
! Cooling
|-
| [[Spacelab Infrared Telescope]] (IRT)
| 1985 || 1.7–118 || 0.15
| Helium
|-
| [[Infrared Space Observatory]] (ISO)<ref>{{cite web|url=https://www.cosmos.esa.int/web/iso/what-is-iso-|title=What is ISO?|publisher=[[ESA]]|date=2016|access-date=4 June 2021}}</ref>
| 1995 || 2.5–240 || 0.60
| Helium
|-
| style="max-width:250px;" | Hubble [[Space Telescope Imaging Spectrograph]] (STIS)
| 1997 || 0.115–1.03 || 2.4
| Passive
|-
| style="max-width:250px;" | Hubble [[Near Infrared Camera and Multi-Object Spectrometer]] (NICMOS)
| 1997 || 0.8–2.4 || 2.4
| Nitrogen, later [[cryocooler]]
|-
| [[Spitzer Space Telescope]]
| 2003 || 3–180 || 0.85
| Helium
|-
| Hubble [[Wide Field Camera 3]] (WFC3)
| 2009 || 0.2–1.7 || 2.4
| Passive, and thermo-electric<ref>{{cite web|url=https://www.nasa.gov/content/hubble-space-telescope-wide-field-camera-3|title=Hubble Space Telescope – Wide Field Camera 3|publisher=NASA|date=22 August 2016}} {{PD-notice}}</ref>
|-
| [[Herschel Space Observatory]]
| 2009 || 55–672 || 3.5
| Helium
|-
| JWST
| 2021 || 0.6–28.5 || 6.5
| Passive, and [[cryocooler]] (MIRI)
|}

JWST's delays and cost increases can be compared to the Hubble Space Telescope.<ref name="nature06"/> When Hubble formally started in 1972, it had an estimated development cost of US$300 million (or about US$1 billion in 2006 constant dollars),<ref name="nature06"/> but by the time it was sent into orbit in 1990, the cost was about four times that.<ref name="nature06"/> In addition, new instruments and servicing missions increased the cost to at least US$9 billion by 2006.<ref name="nature06"/>

Of the other NASA observatories that were proposed around the same time, most have already been canceled or put on hold, including [[Terrestrial Planet Finder]] (2011), [[Space Interferometry Mission]] (2010), [[International X-ray Observatory]] (2011), MAXIM (Microarcsecond X-ray Imaging Mission), [[SAFIR]] (Single Aperture Far-Infrared Observatory), SUVO (Space Ultraviolet-Visible Observatory), and SPECS (Submillimeter Probe of the Evolution of Cosmic Structure).{{citation needed|date=April 2019}}

== History ==
=== Background ===
{{See also|James E. Webb#NASA|James E. Webb#Legacy}}
{| class=wikitable style="float:right; margin-left:0.5em; font-size:88%;"
|+ Selected events
! Year !! Events
|-
| 1996 || NGST started.
|-
| 2002 || named JWST, 8 to 6 m
|-
| 2004 || NEXUS cancelled<ref>{{cite web|url=http://strategic.mit.edu/downloads.php|title=Nexus Space Telescope|publisher=MIT}}</ref>
|-
| 2007 || ESA/NASA MOU
|-
| 2010 || MCDR passed
|-
| 2011 || Proposed cancel
|-
| 2021 || Planned launch
|}

Early development work for a Hubble successor between 1989 and 1994 led to the Hi-Z telescope concept,<ref>{{cite web|url=http://optics.nasa.gov/concept/hi-z.html|publisher=NASA Space Optics Manufacturing Technology Center|title=Advanced Concepts Studies – The 4 m Aperture "Hi-Z" Telescope|url-status=dead|archive-url=https://web.archive.org/web/20111015142938/http://optics.nasa.gov/concept/hi-z.html|archive-date=15 October 2011}} {{PD-notice}}</ref> a fully baffled<ref group="Note">"Baffled", in this context, means enclosed in a tube in a similar manner to a conventional [[optical telescope]], which helps to stop stray light entering the telescope from the side. For an actual example, see the following link: {{cite conference|author=Freniere, E.R.|conference=Radiation Scattering in Optical Systems|book-title=Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, First-order design of optical baffles|volume=257|pages=19–28|date=1981|bibcode=1981SPIE..257...19F|title=First-order design of optical baffles |doi=10.1117/12.959598}}</ref> {{cvt|4|m}} aperture infrared telescope that would recede to an orbit at 3 [[Astronomical unit]] (AU).<ref name="stsci1994">{{cite web |url=http://www.stsci.edu/jwst/overview/history/1994|archive-url=https://wayback.archive-it.org/all/20140203162406/http://www.stsci.edu/jwst/overview/history/1994|url-status=dead|archive-date=3 February 2014 |title=STSCI JWST History 1994|access-date=29 December 2018}}</ref> This distant orbit would have benefited from reduced light noise from [[Zodiacal cloud|zodiacal dust]].<ref name="stsci1994"/> Other early plans called for a NEXUS precursor telescope mission.<ref>{{cite web|url=http://www.nap.edu/html/aanm/web/tier3text/ngst.htm|title=Astrononmy and Astrophysics in the New Millennium|publisher=NASA}} {{PD-notice}}</ref><ref>{{cite book|chapter-url=http://strategic.mit.edu/docs/3_13_SPIE-4849-39.pdf|first1=Olivier L.|title=Highly Innovative Space Telescope Concepts|volume=4849|page=294|last1=de Weck|first2=David W.|last2=Miller|first3=Gary E.|last3=Mosier|s2cid=18725988|editor1-first=Howard A.|editor1-last=MacEwen|date=2002|doi=10.1117/12.460079|series=Highly Innovative Space Telescope Concepts |chapter=Multidisciplinary analysis of the NEXUS precursor space telescope|citeseerx=10.1.1.664.8727|bibcode=2002SPIE.4849..294D}}</ref>

Correcting the disappointing performance of the Hubble Space Telescope in its first years played a significant role in the birth of the JWST. In 1993 NASA readied the Space Shuttle mission that would carry a replacement for HST’s camera and a retrofit for its imaging spectrograph to compensate for the spherical aberration in its primary mirror. While the astronomical community eagerly awaited this mission, NASA cautioned that this extraordinary advance in working in space carried significant risk and that its successful completion was in no way guaranteed. Consequently, the Association of Universities for Research in Astronomy (AURA, the consortium managing the Space Telescope Science Institute) formed a committee of leading American astronomers to evaluate the effectiveness of the repair mission and to explore ideas for future space telescopes that would be needed if the repair mission fell short. The “HST & Beyond Committee,” as it became known, had the good fortune to see the unqualified success of the Space Shuttle Servicing Mission 1 in December 1993 and the unprecedented public response to the stunning images that the HST delivered. The astronomy community, and NASA itself, were no less enthusiastic.

Emboldened by HST’s success, and recognizing innovative work in Europe for future missions<ref>{{Cite journal|last=Thronson|first=H.A.|last2=Hawarden|first2=T.|last3=Davies|first3=J.K.|last4=Lee|first4=T.J.|last5=Mountain|first5=C.M.|last6=Longair|first6=M.|date=January 1991|title=The Edison infrared space observatory and the universe at high redshifts|url=http://dx.doi.org/10.1016/0273-1177(91)90514-k|journal=Advances in Space Research|volume=11|issue=2|pages=341–344|doi=10.1016/0273-1177(91)90514-k|issn=0273-1177}}</ref>,,<ref>{{Cite journal|last=Thronson, Jr.|first=Harley A.|last2=Hawarden|first2=Timothy G.|last3=Bradshaw|first3=Tom W.|last4=Orlowska|first4=Anna H.|last5=Penny|first5=Alan J.|last6=Turner|first6=R. F.|last7=Rapp|first7=Donald|date=1993-11-01|title=<title>Edison radiatively cooled infrared space observatory</title>|url=http://dx.doi.org/10.1117/12.158751|journal=SPIE Proceedings|publisher=SPIE|doi=10.1117/12.158751}}</ref> the HST & Beyond Committee explored the concept of a larger and much colder, infrared-sensitive telescope that could reach back in cosmic time to the birth of the first galaxies. This high-priority science goal was beyond the HST’s capability because, as a warm telescope, it is blinded by infrared emission from its own optical system. In addition to recommendations to extend the HST mission to 2005 and to develop technologies for finding planets around other stars, NASA embraced the chief recommendation of HST & Beyond<ref>Exploration and the Search for Origins: A Vision for Ultraviolet-Optical-Infrared Space Astronomy

REPORT OF THE “HST & BEYOND” COMMITTEE, 1996, ed. A. Dressler, Association of Universities for Research in Astronomy, <nowiki>https://www.stsci.edu/files/live/sites/www/files/home/hst/documentation/_documents/HSTandBeyond.pdf</nowiki>.</ref> for a large, cold space telescope (radiatively cooled to hundreds of degrees below 0 °C), and began the planning process for the future JWST.

Beginning in the 1960s, and at the beginning of each decade since, the National Academies organized the community of U.S. astronomers to think creatively about astronomical instruments and research for the subsequent decade, and to reach consensus on goals and priorities. A faithful supporter of these ‘Decadal Surveys of Astronomy and Astrophysics,’ NASA has also been extraordinarily successful in developing programs and tools to accomplish Survey recommendations. So, even with the substantial support and excitement in the mid-1990s for NASA’s beginning to work on a successor to the HST, the astronomical community regarded as essential a high prioritization by the 2000 Decadal Survey. Preparation for the Survey included further development of the scientific program for what became known as the “Next Generation Space Telescope”,<ref>The Next Generation Space Telescope. Visiting a time when galaxies were young., by Stockman, H. S.. Space Telescope Science Institute, Baltimore, MD (USA)The Association of Universities for Research in Astronomy, Washington, DC (USA), Jun 1997</ref> and advancements in relevant technologies by NASA. As the NGST concept matured, it amplified the importance of a mission studying the birth of galaxies in the young universe, and searching for planets around other stars—the prime goals coalesced as "Origins" by HST & Beyond. Late in the 1990s NASA created the 'Origins Subcommittee' to guide this effort and the 'Beyond Einstein Subcommittee' to oversee missions where the universe is a laboratory for fundamental astrophysics, for example, black holes and supernovae. As hoped, the NGST received the highest ranking in the 2000 Decadal Survey of Astronomy & Astrophysics,<ref>{{Cite book|last=Astronomy and Astrophysics Survey Committee|url=https://www.nap.edu/catalog/9839|title=Astronomy and Astrophysics in the New Millennium|last2=Board on Physics and Astronomy|last3=Space Studies Board|last4=Commission on Physical Sciences, Mathematics, and Applications|last5=National Research Council|date=2001-01-16|publisher=National Academies Press|isbn=978-0-309-07031-7|location=Washington, D.C.|doi=10.17226/9839}}</ref> which allowed the project to proceed with the full endorsement of a community consensus.

The concept that would become JWST originated in 1996, as a proposal named Next Generation Space Telescope (NGST). In 2002, after further development of the design, it was renamed after NASA's second administrator (1961–1968) [[James E. Webb]] (1906–1992). Webb led the agency during the [[Apollo program]] and established scientific research as a core NASA activity.<ref>{{cite web|url=http://www.jwst.nasa.gov/whois.html|title=About James Webb|publisher=NASA|access-date=15 March 2013}} {{PD-notice}}</ref> JWST is a project of [[NASA]], with international collaboration from the [[European Space Agency]] (ESA) and the [[Canadian Space Agency]] (CSA).

In the "faster, better, cheaper" era in the mid-1990s, NASA leaders pushed for a low-cost space telescope.<ref name="stsci1996">{{cite web|url=http://www.stsci.edu/jwst/overview/history/1996|archive-url=https://wayback.archive-it.org/all/20140203162411/http://www.stsci.edu/jwst/overview/history/1996|url-status=dead|archive-date=3 February 2014|title=STSCI JWST History 1996|publisher=Stsci.edu|access-date=16 January 2012}}</ref> The result was the NGST concept, with an 8-meter aperture and located at L2, roughly estimated to cost US$500 million.<ref name="stsci1996"/> In 1997, NASA worked with the Goddard Space Flight Center,<ref>[http://www.spacetelescope.org/images/opo9820b/ Goddard Space Flight Center design] spacetelescope.org. Retrieved on 13 January 2014</ref> [[Ball Aerospace & Technologies]],<ref>[http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29549 ESA Science & Technology: Ball Aerospace design for JWST] {{webarchive |url=https://archive.today/20121212222215/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29549|date=12 December 2012}} Sci.esa.int Retrieved on 21 August 2013</ref> and [[TRW Inc.|TRW]]<ref>[http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29551 ESA Science & Technology: TRW design for JWST] {{webarchive|url=https://archive.today/20121212002141/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29551|date=12 December 2012}} Sci.esa.int Retrieved on 21 August 2013</ref> to conduct technical requirement and cost studies, and in 1999 selected [[Lockheed Martin]]<ref>[http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29550 ESA Science & Technology: Lockheed-Martin design for JWST] {{webarchive|url=https://archive.today/20121213002044/http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=29550|date=13 December 2012}} Sci.esa.int Retrieved on 21 August 2013</ref> and TRW for preliminary concept studies.<ref name="webbpast">{{cite web |url=http://jwstsite.stsci.edu/webb_telescope/webb_past_and_future/|title=HubbleSite – Webb: Past and Future|access-date=13 January 2012|archive-url=https://archive.today/20121210103643/http://jwstsite.stsci.edu/webb_telescope/webb_past_and_future/|archive-date=10 December 2012|url-status=dead}}</ref> Launch was at that time planned for 2007, but the launch date has subsequently been pushed back many times (see table [[#Time, budget|further down]]).

In 2003, NASA awarded TRW the US$824.8 million prime contract for JWST. The design called for a de-scoped {{cvt|6.1|m}} primary mirror and a launch date of 2010.<ref>{{cite web |url=http://www.stsci.edu/jwst/news/2003/nasa-announces-contract|archive-url=https://archive.today/20120805155712/http://www.stsci.edu/jwst/news/2003/nasa-announces-contract|url-status=dead|archive-date=5 August 2012|title=TRW Selected as JWST Prime Contractor|date=11 September 2003|access-date=13 January 2012|publisher=STCI}}</ref> Later that year, TRW was acquired by Northrop Grumman in a hostile bid and became Northrop Grumman Space Technology.<ref name="webbpast"/>

=== Development ===
NASA's Goddard Space Flight Center in Greenbelt, Maryland, is leading the management of the observatory project. The project scientist for the James Webb Space Telescope is [[John C. Mather]]. Northrop Grumman Aerospace Systems serves as the primary contractor for the development and integration of the observatory. They are responsible for developing and building the spacecraft element, which includes both the [[Satellite bus|spacecraft bus]] and sunshield. [[Ball Aerospace & Technologies]] has been subcontracted to develop and build the [[Optical Telescope Element]] (OTE). Northrop Grumman's Astro Aerospace business unit has been contracted to build the Deployable Tower Assembly (DTA) which connects the OTE to the spacecraft bus and the Mid Boom Assembly (MBA) which helps to deploy the large sunshields on orbit.<ref>{{cite news|url=http://www.spacedaily.com/reports/Northrop_Grumman_Completes_Fabrication_Of_Sunshield_Deployment_Flight_Structure_For_JWST_999.html|title=Northrop Grumman Completes Fabrication Of Sunshield Deployment Flight Structure For JWST|publisher=Space Daily|date=13 December 2011|access-date=10 December 2014}}</ref> Goddard Space Flight Center is also responsible for providing the [[Integrated Science Instrument Module]] (ISIM).<ref name="isim">{{cite web|url=https://jwst.nasa.gov/isim.html|title=JWST: Integrated Science Instrument Module (ISIM)|publisher=NASA|date=2017|access-date=2 February 2017}} {{PD-notice}}</ref>

Cost growth revealed in spring 2005 led to an August 2005 re-planning.<ref name="replan"/> The primary technical outcomes of the re-planning were significant changes in the integration and test plans, a 22-month launch delay (from 2011 to 2013), and elimination of system-level testing for observatory modes at wavelength shorter than 1.7 micrometers. Other major features of the observatory were unchanged. Following the re-planning, the project was independently reviewed in April 2006. The review concluded the project was technically sound, but that funding phasing at NASA needed to be changed. NASA re-phased its JWST budgets accordingly.{{citation needed|date=April 2019}}

In the 2005 re-plan, the life-cycle cost of the project was estimated at US$4.5 billion. This comprised approximately US$3.5 billion for design, development, launch and commissioning, and approximately US$1.0 billion for ten years of operations.<ref name="replan">{{cite web|url=http://www7.nationalacademies.org/bpa/CAA_Nov2005_Presentation_Mather.pdf|title=James Webb Space Telescope (JWST)|author=John Mather |publisher=National Academy of Science|access-date=5 July 2008|url-status=dead|archive-url=https://web.archive.org/web/20081110180605/http://www7.nationalacademies.org/bpa/CAA_Nov2005_Presentation_Mather.pdf |archive-date=10 November 2008}} {{PD-notice}}</ref> [[European Space Agency|ESA]] is contributing about €300 million, including the launch.<ref name="ESA Media Relations Service">{{cite press release|url=http://www.esa.int/esaSC/Pr_10_2004_s_en.html|title=European agreement on James Webb Space Telescope's Mid-Infrared Instrument (MIRI) signed|date=9 June 2004|publisher=ESA Media Relations Service|access-date=6 May 2009|archive-date=18 May 2009|archive-url=https://web.archive.org/web/20090518064607/http://www.esa.int/esaSC/Pr_10_2004_s_en.html|url-status=dead}}</ref> The [[Canadian Space Agency]] pledged $39 million Canadian in 2007<ref>{{cite web|last=Agency|first=Canadian Space|date=2007-06-04|title=Canada's contribution to NASA's James Webb Space Telescope|url=https://www.canada.ca/en/news/archive/2007/06/canada-contribution-nasa-james-webb-space-telescope.html|access-date=2021-07-03|website=canada.ca}}</ref> and in 2012 delivered its contributions in equipment to point the telescope and detect atmospheric conditions on distant planets.<ref>{{cite web|date=2012-07-30|title=Canadian Space Agency Delivers Canada's Contributions to the James Webb Space Telescope|url=https://spaceq.ca/canadian_space_agency_delivers_canadas_contributions_to_the_james_webb_space_telescope/|access-date=2021-07-03|website=SpaceQ|language=en-US}}</ref>

=== Construction ===
{{multiple image
| align = right
| total_width = 400
| image1 = James Webb Space Telescope Mirror29.jpg
| caption1 = A JWST mirror segment, 2010
| image2 = James Webb Space Telescope Mirror37.jpg
| caption2 = Mirror segments undergoing [[Cryogenics|cryogenic]] tests at the X-ray & Cryogenic Facility at [[Marshall Space Flight Center]]
}}

[[File:NASA’s James Webb Space Telescope Completes Environmental Testing (50427670958) (cropped).jpg|thumb|upright=1.0|right|The assembled telescope following environmental testing]]

In January 2007, nine of the ten technology development items in the project successfully passed a Non-Advocate Review.<ref>{{cite web|url=http://www.stsci.edu/jwst/news/2007/jwst-passes-tnar|archive-url=https://archive.today/20120805232222/http://www.stsci.edu/jwst/news/2007/jwst-passes-tnar|url-status=dead|archive-date=5 August 2012|title=JWST Passes TNAR|publisher=STScI|access-date=5 July 2008}}</ref> These technologies were deemed sufficiently mature to retire significant risks in the project. The remaining technology development item (the MIRI cryocooler) completed its technology maturation milestone in April 2007. This technology review represented the beginning step in the process that ultimately moved the project into its detailed design phase (Phase C). By May 2007, costs were still on target.<ref>{{cite web|url=http://www.space.com/businesstechnology/070523_techwed_jwst_dock.html|title=NASA Adds Docking Capability For Next Space Observatory|first=Brian|last=Berger|date=May 23, 2007|publisher=SPACE.com|access-date=5 July 2008}}</ref> In March 2008, the project successfully completed its Preliminary Design Review (PDR). In April 2008, the project passed the Non-Advocate Review. Other passed reviews include the [[Integrated Science Instrument Module]] review in March 2009, the [[Optical Telescope Element]] review completed in October 2009, and the Sunshield review completed in January 2010.{{citation needed|date=April 2019}}

In April 2010, the telescope passed the technical portion of its Mission Critical Design Review (MCDR). Passing the MCDR signified the integrated observatory can meet all science and engineering requirements for its mission.<ref>{{cite web|url=http://www.nasa.gov/home/hqnews/2010/apr/HQ_10-099_Webb_Telescope_Milestone.html|title=NASA's Webb Telescope Passes Key Mission Design Review Milestone|publisher=NASA
|access-date=2 May 2010}} {{PD-notice}}</ref> The MCDR encompassed all previous design reviews. The project schedule underwent review during the months following the MCDR, in a process called the Independent Comprehensive Review Panel, which led to a re-plan of the mission aiming for a 2015 launch, but as late as 2018. By 2010, cost over-runs were impacting other projects, though JWST itself remained on schedule.<ref>{{cite web|url=http://www.spaceflightnow.com/news/n1008/12jwst/|title=NASA says JWST cost crunch impeding new missions|first=Stephen|last=Clark|publisher=Spaceflight Now|date=August 12, 2010}}</ref>

By 2011, the JWST project was in the final design and fabrication phase (Phase C). As is typical for a complex design that cannot be changed once launched, there are detailed reviews of every portion of design, construction, and proposed operation. New technological frontiers have been pioneered by the project, and it has passed its design reviews. In the 1990s it was unknown if a telescope so large and low mass was possible.<ref name="ngst1"/>

Assembly of the hexagonal segments of the primary mirror, which was done via robotic arm, began in November 2015 and was completed in February 2016.<ref>{{cite web|url=https://www.nasa.gov/press-release/nasas-james-webb-space-telescope-primary-mirror-fully-assembled|title=NASA's James Webb Space Telescope Primary Mirror Fully Assembled|date=3 February 2016|website=nasa.gov|access-date=4 February 2016}} {{PD-notice}}</ref> Final construction of the Webb telescope was completed in November 2016, after which extensive testing procedures began.<ref>{{cite web|url=https://www.theguardian.com/science/2016/nov/04/nasa-testing-james-webb-space-telescope-gold|title=Nasa begins testing enormous space telescope made of gold mirrors|newspaper=The Guardian|author=Alan Yuhas|date=4 November 2016}}</ref> In March 2018, NASA delayed JWST's launch an additional year to May 2020 after the telescope's sunshield ripped during a practice deployment and the sunshield's cables did not sufficiently tighten. In June 2018, NASA delayed the launch by an additional 10 months to March 2021, based on the assessment of the independent review board convened after the failed March 2018 test deployment.<ref name="NASAJWSTdelay2021"/> The review also found JWST had 344 potential [[single-point failure]]s, any of which could doom the project.<ref>{{cite web|url=https://www.washingtonpost.com/news/speaking-of-science/wp/2018/07/26/northrop-grumman-ceo-is-grilled-about-james-webb-space-telescope-errors/|title=Northrop Grumman CEO is grilled about James Webb Space Telescope errors|last=Achenbach|first=Joel|date=July 26, 2018|newspaper=The Washington Post|access-date=December 28, 2019}}</ref> In August 2019, the mechanical integration of the telescope was completed, something that was scheduled to be done 12 years before in 2007. Following this, engineers were working to add a five layer sunshield in place to prevent damage to telescope parts from infrared rays of the Sun.<ref>{{cite web|url=https://www.businessinsider.in/nasa-hubble-telescope-replacement-james-webb-space-telescope-assembled-after-12-years/articleshow/70886209.cms|title=The two halves of Hubble's US$10 billion successor have finally come together after 12 years of waiting|publisher=Business Insider|access-date=29 August 2019}}</ref>

After construction was completed, JWST underwent final tests at a Northrop Grumman factory in Redondo Beach, California.<ref>{{Cite web|last=Clark|first=Stephen|date=September 30, 2021|title=After two decades, the Webb telescope is finished and on the way to its launch site|url=https://spaceflightnow.com/2021/09/30/webb-on-the-way-to-french-guiana/|url-status=live|website=Spaceflight Now|language=en-US}}</ref> A ship carrying the telescope left California on 26 September 2021, passed the [[Panama Canal]], and arrived in [[French Guiana]] on 12 October 2021.<ref>{{cite web|last=Wall|first=Mike|date=2021-10-12|title=NASA's James Webb Space Telescope arrives in French Guiana ahead of December 18 launch|url=https://www.space.com/nasa-james-webb-space-telescope-arrives-french-guiana|url-status=live|website=Space.com}}</ref>

=== Cost and schedule issues {{anchor|Time, budget}} ===
NASA's lifetime cost for the project is expected to be US$9.7 billion, of which US$8.8 billion was spent on spacecraft design and development and US$861 million is planned to support five years of mission operations.<ref>{{cite web|title=FY 2022 NASA Congressional Budget Justification|url=https://www.nasa.gov/sites/default/files/atoms/files/fy2022_congressional_justification_nasa_budget_request.pdf |publisher=NASA|page=JWST-2}} {{PD-notice}}</ref> Representatives from [[European Space Agency|ESA]] and [[Canadian Space Agency|CSA]] stated their project contributions amount to approximately €700 million and CA$200 million, respectively.<ref>{{cite news|last1=Foust|first1=Jeff|title=JWST launch slips to November|url=https://spacenews.com/jwst-launch-slips-to-november/|publisher=SpaceNews|date=2 June 2021}}</ref>

JWST has a history of major cost overruns and delays which have resulted in part from outside factors such as delays in deciding on a launch vehicle and adding extra funding for contingencies. By 2006, US$1 billion had been spent on developing JWST, with the budget at about US$4.5 billion at that time. A 2006 article in the journal [[Nature (journal)|''Nature'']] noted a study in 1984 by the Space Science Board, which estimated that a next generation infrared observatory would cost US$4 billion (about US$7 billion in 2006 dollars).<ref name="nature06"/>

{| class="wikitable" style="float:right; margin-left:0.5em; font-size:0.9em;"
|+ Then-planned launch and total budget
|-
! Year
! Planned launch
! Budget plan (billion USD)
|-
| 1997 || 2007<ref name="ngst1">{{cite news|url=http://findarticles.com/p/articles/mi_m1571/is_n39_v13/ai_19964936/|title=Next Generation Space Telescope will peer back to the beginning of time and space |publisher=CBS|first=Phil|last=Berardelli|date=27 October 1997}}</ref> || 0.5<ref name="ngst1"/>
|-
| 1998 || 2007<ref>{{cite web|last1=Lilly|first1=Simon|url=http://www.casca.ca/lrp/vol2/ngst/hstng.html|title=The Next Generation Space Telescope (NGST)|publisher=University of Toronto|date=27 November 1998}}</ref> || 1<ref name="nature06"/>
|-
| 1999 || 2007 to 2008<ref>{{cite journal|url=http://www.adass.org/adass/proceedings/adass98/offenbergjd/|title=Cosmic Ray Rejection with NGST|journal=Astronomical Data Analysis Software and Systems Viii
|volume=172|page=141|bibcode=1999ASPC..172..141O|last1=Offenberg|first1=Joel D|last2=Sengupta|first2=Ratnabali|last3=Fixsen|first3=Dale J.|last4=Stockman|first4=Peter|last5=Nieto-Santisteban|first5=Maria
|last6=Stallcup|first6=Scott|last7=Hanisch|first7=Robert|last8=Mather|first8=John C.|year=1999}}</ref> || 1<ref name="nature06"/>
|-
| 2000 || 2009<ref name="miri">{{cite web|url=http://www.astron.nl/miri-ngst/old/public/science/phase-a/text.htm|title=MIRI spectrometer for NGST|url-status=dead| archive-url=https://web.archive.org/web/20110927053021/http://www.astron.nl/miri-ngst/old/public/science/phase-a/text.htm|archive-date=27 September 2011}}</ref> || 1.8<ref name="nature06"/>
|-
| 2002 || 2010<ref>{{cite web|url=http://www.spaceref.com/news/viewsr.html?pid=5319|title=NGST Weekly Missive|date=25 April 2002}}</ref> || 2.5<ref name="nature06"/>
|-
| 2003 || 2011<ref>{{cite web|url=http://www.nasa.gov/home/hqnews/2003/nov/HQ_c03pp_telescope_mod.html|title=NASA Modifies James Webb Space Telescope Contract|date=12 November 2003}} {{PD-notice}}</ref> || 2.5<ref name="nature06">{{cite journal|title=US astronomy: Is the next big thing too big?|first=Tony|last=Reichhardt|date=March 2006|journal=Nature|volume=440|issue=7081|doi=10.1038/440140a|pmid=16525437
|pages=140–143|bibcode=2006Natur.440..140R|doi-access=free}}</ref>
|-
| 2005 || 2013 || 3<ref>{{cite web|url=http://www.spacepolitics.com/2005/05/21/problems-for-jwst/|title=Problems for JWST|date=21 May 2005}}</ref>
|-
| 2006 || 2014 || 4.5<ref>{{cite journal|title=Refocusing NASA's vision|journal=Nature|date=9 March 2006|volume=440|issue=7081|doi=10.1038/440127a|pmid=16525425|page=127|bibcode=2006Natur.440..127.|doi-access=free}}</ref>
|-
|colspan=3 style="text-align:center"|2008, Preliminary Design Review
|-
| 2008 || 2014 || 5.1<ref name="cowen">{{cite web|url=http://news.sciencemag.org/scienceinsider/2011/08/webb-telescope-delayed-costs.html?ref=hp|first=Ron|last=Cowen|title=Webb Telescope Delayed, Costs Rise to $8 Billion|date=25 August 2011|publisher=ScienceInsider|url-status=dead|archive-url=https://web.archive.org/web/20120114105805/http://news.sciencemag.org/scienceinsider/2011/08/webb-telescope-delayed-costs.html?ref=hp|archive-date=14 January 2012}}</ref>
|-
|colspan=3 style="text-align:center"|2010, Critical Design Review
|-
| 2010 || 2015 to 2016 || 6.5<ref name="499224main_JWST-ICRP_Report-FINAL"/>
|-
| 2011 || 2018 || 8.7<ref name="price">{{cite news|url=https://www.bbc.co.uk/news/science-environment-14625362|first=Jonathan|last=Amos|title=JWST price tag now put at over $8 bn|publisher=BBC|date=22 August 2011}}</ref>
|-
| 2013 || 2018 || 8.8<ref name="sciam15">{{cite web|url=https://www.scientificamerican.com/article/nasa-assures-skeptical-congress-that-the-james-webb-telescope-is-on-track/|title=NASA Assures Skeptical Congress That the James Webb Telescope Is on Track|publisher=Scientific American|author=Moskowitz, Clara|date=30 March 2015|access-date=29 January 2017}}</ref>
|-
| 2017 || 2019<ref name="launch 2019">{{cite web|url=https://www.nasa.gov/feature/nasa-s-james-webb-space-telescope-to-be-launched-spring-2019|title=NASA's James Webb Space Telescope to be Launched Spring 2019 |publisher=NASA|date=28 September 2017}} {{PD-notice}}</ref> || 8.8
|-
| 2018 || 2020<ref name=":0">{{cite news|url=https://www.space.com/40102-james-webb-space-telescope-launch-delay-2020.html|title=NASA Delays Launch of James Webb Space Telescope to 2020|publisher=Space.com|access-date=27 March 2018}}</ref> || ≥8.8
|-
| 2019 || March 2021<ref>{{cite web|url=https://www.nasa.gov/press-release/nasa-completes-webb-telescope-review-commits-to-launch-in-early-2021|title=NASA Completes Webb Telescope Review, Commits to Launch in Early 2021|publisher=NASA|website=nasa.gov|date=27 June 2018|access-date=28 June 2018}} {{PD-notice}}</ref> || 9.66
|-
| 2021 || Dec 2021<ref>{{cite web|url=https://spaceflightnow.com/2021/12/14/nasa-delays-launch-of-webb-telescope-to-no-earlier-than-dec-24/|title=NASA delays launch of Webb telescope to no earlier than Dec. 24|date=14 Dec 2021|access-date=14 Dec 2021}} {{PD-notice}}</ref> || 9.70
|}

The telescope was originally estimated to cost US$1.6 billion,<ref name="FLTodayJun11"/> but the cost estimate grew throughout the early development and had reached about US$5 billion by the time the mission was formally confirmed for construction start in 2008. In summer 2010, the mission passed its Critical Design Review (CDR) with excellent grades on all technical matters, but schedule and cost slips at that time prompted Maryland U.S. Senator [[Barbara Mikulski]] to call for an independent review of the project. The Independent Comprehensive Review Panel (ICRP) chaired by J. Casani (JPL) found that the earliest possible launch date was in late 2015 at an extra cost of US$1.5 billion (for a total of US$6.5 billion). They also pointed out that this would have required extra funding in FY2011 and FY2012 and that any later launch date would lead to a higher total cost.<ref name="499224main_JWST-ICRP_Report-FINAL">{{cite web|url=http://www.nasa.gov/pdf/499224main_JWST-ICRP_Report-FINAL.pdf|title=Independent Comprehensive Review Panel, Final Report|date=29 October 2010}} {{PD-notice}}</ref>

On 6 July 2011, the United States House of Representatives' appropriations committee on Commerce, Justice, and Science moved to cancel the James Webb project by proposing an FY2012 budget that removed US$1.9 billion from NASA's overall budget, of which roughly one quarter was for JWST.<ref name="guardian.co.uk">{{cite news|url=https://www.theguardian.com/science/2011/jul/09/nasa-james-webb-space-telescope
|title=Nasa fights to save the James Webb space telescope from the axe|newspaper=The Guardian|location=London|first=Robin|last=McKie|date=9 July 2011}}</ref><ref>{{cite web
|url=http://appropriations.house.gov/news/DocumentSingle.aspx?DocumentID=250023|title=Appropriations Committee Releases the Fiscal Year 2012 Commerce, Justice, Science Appropriations|publisher=US House of representatives Committee on Appropriations|date=6 July 2011}} {{PD-notice}}</ref><ref>{{cite web|url=http://www.spacedaily.com/reports/US_lawmakers_vote_to_kill_Hubble_successor_999.html|title=US lawmakers vote to kill Hubble successor|publisher=SpaceDaily|date=7 July 2011}}</ref><ref>{{cite web|url=http://www.space.com/12187-nasa-budget-bill-cancels-space-telescope-house.html|title=Proposed NASA Budget Bill Would Cancel Major Space Telescope|publisher=Space.com|date=6 July 2011}}</ref> US$3 billion had been spent and 75% of its hardware was in production.<ref>{{cite web|last1=Bergin|first1=Chris|title=James Webb Space Telescope hardware entering key test phase|url=http://www.nasaspaceflight.com/2015/01/jwst-hardware-entering-test-phase/|publisher=NASASpaceFlight.com|date=7 January 2015|access-date=28 August 2016}}</ref> This budget proposal was approved by subcommittee vote the following day. The committee charged that the project was "billions of dollars over budget and plagued by poor management".<ref name="guardian.co.uk"/> In response, the [[American Astronomical Society]] issued a statement in support of JWST,<ref>{{cite web|url=https://aas.org/media/press-releases/aas-issues-statement-proposed-cancellation-james-webb-space-telescope|title=AAS Issues Statement on Proposed Cancellation of James Webb Space Telescope|author=Hand E.|date=7 July 2011|publisher=American Astronomical Society}}</ref> as did Maryland US Senator Barbara Mikulski.<ref>{{cite web|url=http://www.spaceref.com/news/viewpr.html?pid=34063|title=Mikulski Statement On House Appropriations Subcommittee Termination of James Webb Telescop |publisher=SpaceRef|date=11 July 2011}}</ref> A number of editorials supporting JWST appeared in the international press during 2011 as well.<ref name="guardian.co.uk"/><ref>{{cite news |url=https://www.nytimes.com/2011/07/10/opinion/sunday/10sun2.html?ref=opinion|title=Way Above the Shuttle Flight|date=9 July 2011|newspaper=The New York Times}}</ref><ref>{{cite web |url=https://vancouversun.com/technology/space-shuttle/news+Canada+could+scrap+space+telescope/5067942/story.html|title=Bad news for Canada: U.S. could scrap new space telescope|last=Harrold|first=Max |newspaper=The Vancouver Sun|date=7 July 2011}}</ref> In November 2011, Congress reversed plans to cancel JWST and instead capped additional funding to complete the project at US$8 billion.<ref>{{cite news |title=NASA budget plan saves telescope, cuts space taxis|url=https://www.reuters.com/article/us-usa-space-budget-idUSTRE7AF06320111116|work=Reuters|date=16 November 2011|access-date=1 July 2017|archive-date=24 September 2015|archive-url=https://web.archive.org/web/20150924160524/http://www.reuters.com/article/2011/11/16/us-usa-space-budget-idUSTRE7AF06320111116|url-status=live}}</ref>

Some scientists have expressed concerns about growing costs and schedule delays for the Webb telescope, which competes for scant astronomy budgets and thus threatens funding for other space science programs.<ref name="SpaceNov12">{{cite news|url=http://www.space.com/13528-nasa-jwst-telescope-funding-delay-science-missions.html|title=NASA Acknowledges James Webb Telescope Costs Will Delay Other Science Missions |first=Dan|last=Leone|publisher=SpaceNews|date=7 November 2012}}</ref><ref name=sciam15/> Because the runaway budget diverted funding from other research, a 2010 ''Nature'' article described JWST as "the telescope that ate astronomy".<ref>{{cite journal|title=The telescope that ate astronomy|journal=Nature|volume=467|issue=7319|pages=1028–1030|date=27 October 2010|doi=10.1038/4671028a|pmid=20981068 |last1=Billings|first1=Lee|doi-access=free}}</ref>

A review of NASA budget records and status reports noted that JWST is plagued by many of the same problems that have affected other major NASA projects. Repairs and additional testing included underestimates of the telescope's cost that failed to budget for expected technical glitches and missed budget projections, thus extending the schedule and increasing costs further.<ref name="sciam15"/><ref name="FLTodayJun11">{{cite web|url=http://www.floridatoday.com/article/20110605/NEWS01/110604013/Telescope-debacle-devours-NASA-funds.html|title=Telescope debacle devours NASA funds. Hubble's successor is billions of dollars over budget, 7 years late|newspaper=Florida Today|author=Kelly, John|date=5 June 2011|archive-url=https://web.archive.org/web/20140403051459/http://www.floridatoday.com/article/20110605/NEWS01/110604013/Telescope-debacle-devours-NASA-funds.html|url-status=dead|archive-date=3 April 2014}}</ref><ref name="atlantic">{{cite web|url=https://www.theatlantic.com/science/archive/2016/12/james-webb-space-telescope-goddard/509840/|title=The Extreme Hazing of the Most Expensive Telescope Ever Built|author=Koren, Marina|date=7 December 2016|publisher=The Atlantic|access-date=29 January 2017}}</ref>

On 27 March 2018, NASA announced that JWST's launch would be pushed back to May 2020 or later, admitting that the project's costs might exceed US$8.8 billion.<ref name=":0"/> NASA committed to releasing a revised cost estimate after a new launch window was determined with the [[European Space Agency]] (ESA).<ref name="NASA-20180327">{{cite news|url=https://www.nasa.gov/press-release/nasa-s-webb-observatory-requires-more-time-for-testing-and-evaluation-new-launch |title=NASA's Webb Observatory Requires More Time for Testing and Evaluation|last1=Wang|first1=Jen Rae|last2=Cole|first2=Steve|last3=Northon|first3=Karen|date=27 March 2018|publisher=NASA|access-date=27 March 2018}} {{PD-notice}}</ref> If this cost estimate exceeds the US$8 billion cap Congress put in place in 2011, as is considered unavoidable, NASA must have the mission re-authorized by the legislature.<ref>{{cite news|url=https://www.bbc.com/news/science-environment-43559980|title=Hubble 'successor' faces new delay|last=Amos|first=Jonathan|date=27 March 2018|publisher=BBC News|access-date=27 March 2018}}</ref><ref>{{cite news|url=https://www.nature.com/articles/d41586-018-03863-5|title=NASA reveals major delay for $8-billion Hubble successor|last=Witze|first=Alexandra|doi=10.1038/d41586-018-03863-5 |bibcode=2018Natur.556...11W|date=27 March 2018|access-date=27 March 2018}}</ref>

In February 2019, despite expressing criticism over cost growth, Congress increased the mission's cost cap by US$800 million.<ref>{{cite news|url=http://www.planetary.org/blogs/casey-dreier/2019/0215-fy2019-nasa-gets-its-best-budget-in-decades.html|title=NASA just got its best budget in a decade|last=Dreier|first=Casey|date=15 February 2019}}</ref>

=== Partnership ===
NASA, ESA and CSA have collaborated on the telescope since 1996. ESA's participation in construction and launch was approved by its members in 2003 and an agreement was signed between ESA and NASA in 2007. In exchange for full partnership, representation and access to the observatory for its astronomers, ESA is providing the NIRSpec instrument, the Optical Bench Assembly of the MIRI instrument, an [[Ariane 5|Ariane 5 ECA]] launcher, and manpower to support operations.<ref name="ESA Media Relations Service"/><ref>[http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=45728 ESA Science & Technology: Europe's Contributions to the JWST Mission]</ref> The CSA will provide the Fine Guidance Sensor and the Near-Infrared Imager Slitless Spectrograph plus manpower to support operations.<ref>[https://web.archive.org/web/20130412124143/http://www.asc-csa.gc.ca/eng/media/news_releases/2012/0730.asp Canadian Space Agency "Eyes" Hubble's Successor: Canada Delivers its Contribution to the World's Most Powerful Space Telescope – Canadian Space Agency]</ref>

Several thousand scientists, engineers, and technicians spanning 15 countries have contributed to JWST.<ref name="jenner010620">{{Cite web|last=Jenner|first=Lynn|date=2020-06-01|title=NASA's Webb Telescope is an International Endeavor|url=http://www.nasa.gov/feature/goddard/2020/nasa-s-webb-telescope-is-an-international-endeavor|access-date=2021-09-23|website=NASA}}</ref> A total of 258 companies, government agencies, and academic institutions are participating in the project; 142 from the United States, 104 from 12 European countries, and 12 from Canada.<ref name="jenner010620"/>

;Participating countries
{{div col|colwidth=22em}}
* {{flagcountry|Austria}}
* {{flagcountry|Belgium|state}}
* {{flagcountry|Canada}}
* {{flagcountry|Czechia}}
* {{flagcountry|Denmark}}
* {{flagcountry|Finland}}
* {{flagcountry|France}}
* {{flagcountry|Germany}}
* {{flagcountry|Greece}}
* {{flagcountry|Ireland}}
* {{flagcountry|Italy}}
* {{flagcountry|Luxembourg}}
* {{flagcountry|Netherlands}}
* {{flagcountry|Norway}}
* {{flagcountry|Portugal}}
* {{flagcountry|Spain}}
* {{flagcountry|Sweden}}
* {{flagcountry|Switzerland}}
* {{flagcountry|United Kingdom}}
* {{flagcountry|United States}}
{{div col end}}

=== Public displays and outreach ===
[[File:JWST people.jpg|thumb|upright=1.0|right|Early full-scale model on display at NASA [[Goddard Space Flight Center]] (2005)]]

A large telescope model has been on display at various places since 2005: in the United States at [[Seattle, Washington]]; [[Colorado Springs, Colorado]]; [[Greenbelt, Maryland]]; [[Rochester, New York]]; [[New York City]]; and [[Orlando, Florida]]; and elsewhere at [[Paris]], France; [[Dublin]], Ireland; [[Montreal]], Canada; Hatfield, United Kingdom; and [[Munich]], Germany. The model was built by the main contractor, Northrop Grumman Aerospace Systems.<ref>{{cite web|url=http://www.spacedaily.com/reports/Webb_Slinger_Heads_To_Washington_999.html|title=Webb Slinger Heads To Washington|publisher=Space Daily|date=8 May 2007}}</ref>

In May 2007, a full-scale model of the telescope was assembled for display at the [[Smithsonian Institution]]'s [[National Air and Space Museum]] on the [[National Mall]], [[Washington, D.C.]] The model was intended to give the viewing public a better understanding of the size, scale and complexity of the satellite, as well as pique the interest of viewers in science and astronomy in general. The model is significantly different from the telescope, as the model must withstand gravity and weather, so is constructed mainly of aluminum and steel measuring approximately {{cvt|24|x|12|x|12|m}} and weighs {{cvt|5500|kg}}.<ref>{{cite web |title=Full-Scale Model of the JWST Spacecraft |url=https://sci.esa.int/web/jwst/-/45584-full-scale-model-of-the-jwst-spacecraft |publisher=European Space Agency |access-date=7 October 2021 |date=1 September 2019}}</ref>

The model was on display in New York City's [[Battery Park]] during the 2010 [[World Science Festival]], where it served as the backdrop for a panel discussion featuring [[Nobel Prize]] laureate John C. Mather, astronaut [[John M. Grunsfeld]] and astronomer [[Heidi Hammel]]. In March 2013, the model was on display in [[Austin, Texas|Austin]] for [[South by Southwest|SXSW 2013]].<ref>{{cite web |url=http://www.nasa.gov/externalflash/JWSTSXSW/event.html|title=NASA's Webb Space Telescope Has Landed in Austin!|publisher=NASA|date=March 2013|url-status=dead|archive-url=https://web.archive.org/web/20130310043051/http://www.nasa.gov/externalflash/JWSTSXSW/event.html|archive-date=10 March 2013}} {{PD-notice}}</ref><ref>{{cite web |url=http://www.latimes.com/news/science/sciencenow/la-sci-sn-sxsw-jwst-james-webb-space-telescope-nasa-south-by-southwest-20130308,0,3337690.story|title=NASA James Webb Space Telescope model lands at South by Southwest|newspaper=Los Angeles Times|author=Khan, Amina|date=8 March 2013}}</ref> [[Amber Straughn]], the deputy project scientist for science communications, has been a spokesperson for the project at many SXSW events from 2013 on in addition to Comic Con, TEDx, and other public venues.<ref>{{cite web|url=https://www.jwst.nasa.gov/content/meetTheTeam/people/straughn.html|title=Team Biography of Amber Straughn
|access-date=20 June 2020}} {{PD-notice}}</ref>

=== Controversy over name ===
In March, 2021, an article by several scientists in ''Scientific American'' urged NASA to reconsider the name of the telescope, based on Webb's alleged complicity in LGBTQ discrimination.<ref name="WP-20211013">{{cite news|last=Mark|first=Juian|title=NASA's James Webb telescope will explore the universe. Critics say its name represents a painful time in U.S. history.| url=https://www.washingtonpost.com/nation/2021/10/13/nasa-james-webb-telescope-name-controversy/ |date=13 October 2021|newspaper=The Washington Post|access-date=13 October 2021}}</ref> In January 2021, astrophysicist [[Hakeem Oluseyi]] explained that a quote displayed on Webb's [[Wikipedia]] article from 2011 to 2015, which implied him to be [[homophobic]], had been wrongly attributed to him.<ref>{{cite web|last=Oluseyi|first=Hakeem|date=23 January 2021|title=Was NASA's Historic Leader James Webb a Bigot?|url=https://hmoluseyi.medium.com/was-nasas-historic-leader-james-webb-a-bigot-131c821d5f12 |url-status=live|access-date=18 November 2021|website=Medium}}</ref>

In September 2021, it was reported that NASA had decided not to rename the telescope.<ref name="NYT-20211020">{{cite news|last=Overbye|first=Dennis|author-link=Dennis Overbye |title=The Webb Telescope's Latest Stumbling Block: Its Name - The long-awaited successor to the Hubble Space Telescope is scheduled to launch in December. But the NASA official for whom it is named has been accused of homophobia.|url=https://www.nytimes.com/2021/10/20/science/webb-telescope-astronomy-homophobia.html|date=20 October 2021|newspaper=The New York Times|access-date=21 October 2021}}</ref> Former administrator [[Sean O'Keefe]], who made the decision to name the telescope after Webb, denounced [[Heterosexism|the discrimination]] of "talented professionals on the basis of their personal preferences", but stated that to suggest Webb should "be held accountable for that activity when there's no evidence to even hint [that he participated in it] is an injustice".<ref name="NPR-20210930">{{cite news |last=Greenfieldboyce|first=Nell|date=September 30, 2021|title=Shadowed by controversy, NASA won't rename its new space telescope|publisher=NPR|url=https://www.npr.org/2021/09/30/1041707730/shadowed-by-controversy-nasa-wont-rename-new-space-telescope|access-date=2021-10-27}}</ref> In response to this decision one member of NASA's Astrophysics Advisory Committee (APAC) resigned.<ref name="PW-20211012">{{cite news|last=Banks|first=Michael|title=NASA hit by resignation over its handling of investigation into telescope renaming|url=https://physicsworld.com/a/nasa-hit-by-resignation-over-its-handling-of-investigation-into-telescope-renaming/|date=12 October 2021 |publisher=PhysicsWorld|access-date=12 October 2021}}</ref><ref name="BUS-20211015">{{cite news|last=Duffy|first=Kate|title=NASA advisor quits after the agency keeps a US$10 billion telescope named after James Webb, who was a senior State Department official during the persecution of gay and lesbian government employees|url=https://www.businessinsider.com/james-webb-teslescope-nasa-advisor-lucianne-walkowicz-quits-homophobic-2021-10|date=October 15, 2021|publisher=Business Insider|access-date=October 15, 2021}}</ref><ref name="AL-20211018">{{cite news|last=Gore|first=Laeda|title=Resignation follows NASA rejection of James Webb Space Telescope renaming|url=https://www.al.com/news/2021/10/resignation-follows-nasa-rejection-of-james-webb-space-telescope-renaming.html|date=October 18, 2021|publisher=Al.com|access-date=October 18, 2021}}</ref><ref>{{cite news|last=Savage|first=Dan|date=21 January 2015|title=Should NASA Name a Telescope After a Dead Guy Who Persecuted Gay People in the 1950s?|newspaper=The Stranger |url=https://www.thestranger.com/slog/archives/2015/01/21/should-nasa-name-a-telescope-after-a-dead-guy-who-persecuted-gay-people-in-the-1950s|access-date=27 October 2021}}</ref>

== Mission ==
The James Webb Space Telescope has four key goals:
* to search for light from the first stars and galaxies that formed in the [[Universe]] after the [[Big Bang]]
* to study the [[galaxy formation and evolution|formation and evolution of galaxies]]
* to understand the [[star formation|formation of stars]] and [[planet formation|planetary systems]]
* to study planetary systems and the [[Abiogenesis|origins of life]].<ref>{{cite web|author1=Maggie Masetti|author2=Anita Krishnamurthi|url=http://www.jwst.nasa.gov/science.html|title=JWST Science |publisher=NASA|date=2009|access-date=14 April 2013}} {{PD-notice}}</ref>

These goals can be accomplished more effectively by observation in near-infrared light rather than light in the visible part of the spectrum. For this reason, JWST's instruments will not measure visible or ultraviolet light like the Hubble Telescope, but will have a much greater capacity to perform [[infrared astronomy]]. JWST will be sensitive to a range of wavelengths from 0.6 (orange light) to 28 [[micrometre]]s (deep infrared radiation at about {{cvt|100|K}}).

JWST may be used to gather information on the dimming light of star [[Tabby's Star|KIC 8462852]], which was discovered in 2015, and has some abnormal light-curve properties.<ref>{{cite web |url=http://www.popularmechanics.com/space/telescopes/a19346/james-webb-telescope-alien-megastructure/ |title=NASA's Next Telescope Could ID Alien Megastructures|date=9 February 2016|access-date=1 September 2016}}</ref>

=== Launch and mission length ===
[[File:JWST inside the Ariane rocket.jpg|thumb|upright=1.3|JWST inside the Ariane rocket]]
{{Main|Ariane flight VA256}}

{{As of|2021|12}}, the launch (designated [[Ariane flight VA256]]) is scheduled for no earlier than 24 December 2021 on an [[Ariane 5]] launch vehicle from the [[Guiana Space Centre]] in [[French Guiana]].<ref name="24dec" /><ref>{{cite web |title=NASA Provides Update on Webb Telescope Launch – James Webb Space Telescope|url=https://blogs.nasa.gov/webb/2021/11/22/nasa-provides-update-on-webb-telescope-launch/|access-date=2021-11-22 |website=blogs.nasa.gov}} {{PD-notice}}</ref><ref>[https://www.newsweek.com/when-will-james-webb-telescope-launch-who-james-webb-video-shows-unboxed-nasa-controversy-1646870 Unboxing the telescope]</ref> The observatory attaches to the Ariane 5 launch vehicle via a launch vehicle adapter ring which could be used by a future spacecraft to grapple the observatory to attempt to fix gross deployment problems. However, the telescope itself is not serviceable, and astronauts would not be able to perform tasks such as swapping instruments, as with the Hubble Telescope.<ref name=howBig/>

The telescope's nominal mission time is five years, with a goal of ten years.<ref name="About the Webb">{{cite web|url=http://www.jwst.nasa.gov/about.html|title=About the Webb|publisher=NASA James Webb Space Telescope|date=2017}} {{PD-notice}}</ref> The planned five-year science mission begins after a 6-month commissioning phase.<ref name="HowLong" /> JWST needs to use propellant to maintain its halo orbit around L2, which provides an upper limit to its designed lifetime, and it is being designed to carry enough for ten years.<ref name="HowLong">{{cite web |url=http://jwst.nasa.gov/faq.html#howlong|title=Frequently asked questions: How long will the Webb mission last?|publisher=NASA James Webb Space Telescope|date=2017}} {{PD-notice}}</ref> An L2 orbit is [[Stability theory|unstable]], so it requires [[orbital station-keeping]], or the telescope will drift away from this orbital configuration.<ref>{{cite web|title=JWST Orbit|url=https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-orbit|publisher=James Webb Space Telescope User Documentation|access-date=8 September 2021}}</ref>

=== Orbit ===
[[File:L2 rendering.jpg|thumb|upright=1.0|right|JWST will not be exactly at the L2 point, but circle around it in a [[halo orbit]].]]
[[File:Carina Nebula in Visible and Infrared.jpg|thumb|upright=1.0|right|Two alternate [[Hubble Space Telescope]] views of the [[Carina Nebula]], comparing ultraviolet and visible (top) and infrared (bottom) astronomy. Far more stars are visible in the latter.]]

JWST will be located near the second [[Lagrange point]] (L2) of the Earth-Sun system, which is {{cvt|1500000|km}} from Earth, directly opposite to the Sun. Normally an object circling the Sun farther out than Earth would take longer than one year to complete its orbit, but near the L2 point the combined gravitational pull of the Earth and the Sun allow a spacecraft to orbit the Sun in the same time it takes the Earth. The telescope will circle about the L2 point in a [[halo orbit]], which will be inclined with respect to the [[ecliptic]], have a radius of approximately {{cvt|800000|km}}, and take about half a year to complete.<ref name="stsci.edu"/> Since L2 is just an equilibrium point with no gravitational pull, a halo orbit is not an orbit in the usual sense: the spacecraft is actually in orbit around the Sun, and the halo orbit can be thought of as controlled drifting to remain in the vicinity of the L2 point.<ref>{{cite web|title=Basics of Space Flight|url=http://www2.jpl.nasa.gov/basics/bsf5-1.php|publisher=Jet Propulsion Laboratory|access-date=28 August 2016}} {{PD-notice}}</ref> This requires some [[Orbital station-keeping|station-keeping]]: around {{val|2|-|4|u=m/s}} per year<ref>{{cite web |url=http://snap.lbl.gov/pub/bscw.cgi/S4d1692c5/d84092/SNAP-TECH-03010.pdf|title=STScI NGST Libration Point Introduction|author=Michael Mesarch|publisher=NASA/GSFC Guidance Navigation and Control Center|date=31 March 1999|access-date=17 January 2011|archive-url=https://web.archive.org/web/20110927154647/http://snap.lbl.gov/pub/bscw.cgi/d84092/SNAP-TECH-03010.pdf|archive-date=27 September 2011|url-status=dead}} {{PD-notice}}</ref> from the total [[Delta-v|∆''v'']] budget of {{val|150|u=m/s}}.<ref>{{cite web|url=http://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-MAD-ARI-03-4103a-InterplanetaryHighways-Barcellona.pdf |title=Assessment of Mission Design Including Utilization of Libration Points and Weak Stability Boundaries|author=E.Canalias, G.Gomez, M.Marcote, J.J.Masdemont|publisher=Department de Matematica Aplicada, Universitat Politecnica de Catalunya and Department de Matematica Aplicada, Universitat de Barcellona}}</ref> Two sets of thrusters constitute the observatory's propulsion system.<ref>"[https://ntrs.nasa.gov/search.jsp?R=20140008868 James Webb Space Telescope Initial Mid-Course Correction Monte Carlo Implementation using Task Parallelism]" 3.1 Propulsion System Overview. J. Petersen et al. {{PD-notice}}</ref>

=== Infrared astronomy ===
[[File:HUDF-JD2.jpg|thumb|upright=1.0|right|Infrared observations can see objects hidden in visible light, such as the [[HUDF-JD2]] shown here.]]

JWST is the formal successor to the Hubble Space Telescope (HST), and since its primary emphasis is on [[infrared astronomy]], it is also a successor to the [[Spitzer Space Telescope]]. JWST will far surpass both those telescopes, being able to see many more and much older stars and galaxies.<ref name=RHowardJWST>Howard, Rick, [https://www.nasa.gov/pdf/629955main_RHoward_JWST_3_6_12.pdf "James Webb Space Telescope (JWST)"], ''nasa.gov'', 6 March 2012 {{PD-notice}}</ref> Observing in the infrared spectrum is a key technique for achieving this, because of [[cosmological redshift]], and because it better penetrates obscuring dust and gas. This allows observation of dimmer, cooler objects. Since water vapor and carbon dioxide in the Earth's atmosphere strongly absorbs most infrared, ground-based infrared astronomy is limited to narrow wavelength ranges where the atmosphere absorbs less strongly. Additionally, the atmosphere itself radiates in the infrared spectrum, often overwhelming light from the object being observed. This makes a space telescope preferable for infrared observation.<ref>{{cite web|url=http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/irwindows.html|title=Infrared Atmospheric Windows
|publisher=Cool Cosmos|access-date=28 August 2016}}</ref>

The more distant an object is, the younger it appears; its light has taken longer to reach human observers. Because the [[Expansion of the universe|universe is expanding]], as the light travels it becomes red-shifted, and objects at extreme distances are therefore easier to see if viewed in the infrared.<ref name="ir_astronomy"/> JWST's infrared capabilities are expected to let it see back in time to the first galaxies forming just a few hundred million years after the Big Bang.<ref name="firstlight">{{cite web|url=http://www.jwst.nasa.gov/firstlight.html|title=Webb Science: The End of the Dark Ages: First Light and Reionization|publisher=NASA|access-date=9 June 2011}} {{PD-notice}}</ref>

Infrared radiation can pass more freely through regions of [[cosmic dust]] that scatter visible light. Observations in infrared allow the study of objects and regions of space which would be obscured by gas and dust in the [[visible spectrum]],<ref name="ir_astronomy">{{cite web|url=http://www.ipac.caltech.edu/Outreach/Edu/importance.html|title=Infrared Astronomy: Overview|publisher=NASA Infrared Astronomy and Processing Center|access-date=30 October 2006|url-status=dead|archive-url=https://web.archive.org/web/20061208151300/http://www.ipac.caltech.edu/Outreach/Edu/importance.html|archive-date=8 December 2006}} {{PD-notice}}</ref> such as the [[molecular cloud]]s where stars are born, the [[circumstellar disks]] that give rise to planets, and the cores of [[active galaxy|active galaxies]].<ref name="ir_astronomy"/>

Relatively cool objects (temperatures less than several thousand degrees) emit their radiation primarily in the infrared, as described by [[Planck's law]]. As a result, most objects that are cooler than stars are better studied in the infrared.<ref name="ir_astronomy"/> This includes the clouds of the [[interstellar medium]], [[brown dwarf]]s, [[planet]]s both in our own and other solar systems, [[comet]]s, and [[Kuiper belt|Kuiper belt objects]] that will be observed with the Mid-Infrared Instrument (MIRI).<ref name=miri/><ref name=firstlight/>

Some of the missions in infrared astronomy that impacted JWST development were [[Spitzer Space Telescope|Spitzer]] and the [[Wilkinson Microwave Anisotropy Probe]] (WMAP).<ref name="ssb-2006">{{cite web |last=Mather |first=John |url=https://jwst.nasa.gov/resources/ssb_2006/mather_sciencesummary.pdf |title=James Webb Space Telescope (JWST) Science Summary for SSB |work=[[NASA]] |date=13 June 2006 |access-date=4 June 2021}} {{PD-notice}}</ref> Spitzer showed the importance of mid-infrared, which is helpful for tasks such as observing dust disks around stars.<ref name="ssb-2006"/> Also, the WMAP probe showed the universe was "lit up" at redshift 17, further underscoring the importance of the mid-infrared.<ref name="ssb-2006"/> Both these missions were launched in the early 2000s, in time to influence JWST development.<ref name="ssb-2006"/>

=== Ground support and operations ===
The [[Space Telescope Science Institute]] (STScI), located in [[Baltimore, Maryland]], on the [[Homewood Campus of Johns Hopkins University]], was selected as the Science and Operations Center (S&OC) for JWST with an initial budget of US$162.2 million intended to support operations through the first year after launch.<ref>{{cite web|url=https://www.nasa.gov/home/hqnews/2003/jun/HQ_c03r_Webb.html|title=Webb Spacecraft Science & Operations Center Contract Awarded|authors=Savage, Donald and Neal, Nancy|date=6 June 2003|publisher=NASA|access-date=1 February 2017}} {{PD-notice}}</ref> In this capacity, STScI will be responsible for the scientific operation of the telescope and delivery of data products to the astronomical community. Data will be transmitted from JWST to the ground via the [[NASA Deep Space Network]], processed and calibrated at STScI, and then distributed online to astronomers worldwide. Similar to how Hubble is operated, anyone, anywhere in the world, will be allowed to submit proposals for observations. Each year several committees of astronomers will [[peer review]] the submitted proposals to select the projects to observe in the coming year. The authors of the chosen proposals will typically have one year of private access to the new observations, after which the data will become publicly available for download by anyone from the online archive at STScI.

The bandwidth and digital throughput of the satellite is designed to operate at 458 gigabits of data per day for the length of the mission.<ref name="wired-20191022"/> Most of the data processing on the telescope is done by conventional single-board computers.<ref>{{cite web|url=http://www.fbodaily.com/archive/2002/10-October/30-Oct-2002/FBO-00195113.htm|title=Single Board Computer|publisher=FBO Daily Issue, FBO #0332|date=30 October 2002}}</ref> The conversion of the analog science data to digital form is performed by the custom-built SIDECAR ASIC (System for Image Digitization, Enhancement, Control And Retrieval [[Application-specific integrated circuit|Application Specific Integrated Circuit]]). NASA stated that the SIDECAR ASIC will include all the functions of a {{cvt|9.1|kg}} instrument box in a {{cvt|3|cm}} package and consume only 11 milliwatts of power.<ref name="Sidecar">{{cite web|url=http://www.nasa.gov/topics/universe/features/jwst_digital.html|title=Amazing Miniaturized 'SIDECAR' Drives Webb Telescope's Signal|date=20 February 2008|publisher=NASA|access-date=22 February 2008}} {{PD-notice}}</ref> Since this conversion must be done close to the detectors, on the cool side of the telescope, the low power use of this IC will be crucial for maintaining the low temperature required for optimal operation of JWST.<ref name="Sidecar"/>

=== After-launch deployment ===
Nearly a month after launch, a trajectory correction will be initiated to place JWST into a [[halo orbit]] at the L2 [[Lagrange point]].<ref>{{cite web|url=https://www.newsledge.com/james-webb-space-telescope-first-30-days/|title=James Webb Space Telescope – The First 30 Days After Launch|date=3 March 2017|publisher=News Ledge}}</ref>{{Clarify|reason=Any other details? How will separation work? How will JWST orient itself correctly? Details of the assembly process, where hexagonal mirrors are put in place and sunshield is deployed? How many stages and at what points do they separate/get discarded?|date=February 2021}}

Once in position, JWST will go through the process of deploying its sunshade, mirror, and arm, which will take around three weeks.<ref name=":1">{{Citation|title=An Introduction to the James Webb Space Telescope Mission|url=https://www.youtube.com/watch?v=6VqG3Jazrfs |archive-url=https://ghostarchive.org/varchive/youtube/20211212/6VqG3Jazrfs| archive-date=2021-12-12 |url-status=live|pages=2:45|language=en|access-date=2021-02-20}}{{cbignore}}</ref> The mirror is in three pieces that will swing into place with motors.<ref name=":1" />

<gallery align="left" mode="packed" heights="300px">
File:JWSTDeployment.jpg|JWST after-launch deployment planned timeline<ref name=howBig/>
</gallery>

{{multiple image | align = center | direction = horizontal| width = 300
| header = Animation of James Webb Space Telescope trajectory
| image1 = Animation of James Webb Space Telescope trajectory - Polar view.gif
| caption1 = Top view
| image2 = Animation of James Webb Space Telescope trajectory - Equatorial view.gif
| caption2 = Side view
| image3 = Animation of James Webb Space Telescope trajectory - Viewed from the Sun.gif
| caption3 = Side view from the Sun
| footer =
}}

== Allocation of observation time ==
JWST observing time will be allocated through a General Observers (GO) program, a Guaranteed Time Observations (GTO) program, and a Director's Discretionary Early Release Science (DD-ERS) program.<ref>{{cite web|title=Calls for Proposals & Policy|url=https://jwst.stsci.edu/science-planning/calls-for-proposals-and-policy|publisher=Space Telescope Science Institute|access-date=13 November 2017}} {{PD-notice}}</ref> The GTO program provides guaranteed observing time for scientists who developed hardware and software components for the observatory. The GO program provides all astronomers the opportunity to apply for observing time and will represent the bulk of the observing time. GO programs will be selected through peer review by a Time Allocation Committee (TAC), similar to the proposal review process used for the Hubble Space Telescope. JWST observing time is expected to be highly oversubscribed.

=== Early Release Science Program ===
[[File:Atmospheric Transmission-en.svg|thumb|upright=1.0|right|Atmospheric windows in the infrared: Much of this type of light is blocked when viewed from the Earth's surface. It would be like looking at a rainbow but only seeing one color.]]

In November 2017, the Space Telescope Science Institute announced the selection of 13 Director's Discretionary Early Release Science (DD-ERS) programs, chosen through a competitive proposal process.<ref>{{cite web|title=Selections Made for the JWST Director's Discretionary Early Release Science Program|url=https://jwst.stsci.edu/news-events/news/News%20items/selections-made-for-the-jwst-directors-discretionary-early-release-science-program|publisher=Space Telescope Science Institute|access-date=13 November 2017|archive-url=https://wayback.archive-it.org/all/20180808190059/https://jwst.stsci.edu/news-events/news/News%2520items/selections-made-for-the-jwst-directors-discretionary-early-release-science-program|archive-date=8 August 2018|url-status=dead}} {{PD-notice}}</ref> The observations for these programs will be obtained during the first five months of JWST science operations after the end of the commissioning period. A total of 460 hours of observing time was awarded to these 13 programs, which span science topics including the [[Solar System]], [[exoplanet]]s, [[star]]s and [[star formation]], nearby and distant [[Galaxy|galaxies]], [[gravitational lens]]es, and [[quasar]]s.

=== General Observer Program ===
Selection of Cycle 1 GO programs was announced on 30 March 2021. In the Cycle 1 proposal review, 266 proposals were approved, including 13 large and treasury programs.<ref>{{cite web|title=STScI Announces the JWST Cycle 1 General Observer Program|url=https://www.stsci.edu/contents/news/jwst/2021/stsci-announces-the-jwst-cycle-1-general-observer-program|access-date=30 March 2021}}</ref>

== See also ==
{{div col|colwidth=30em}}
* [[Attitude control]]
* [[James Webb Space Telescope timeline]]
* [[List of largest infrared telescopes]]
* [[List of largest optical reflecting telescopes]]
* [[List of space telescopes]]
* [[Nancy Grace Roman Space Telescope]], planned launch no later than 2027
* [[New Worlds Mission]] (proposed occulter for the JWST)
* [[Physical cosmology]]
* [[Satellite bus]]
* [[Solar panels on spacecraft]]
* [[Spacecraft design]]
* [[Spacecraft thermal control]]
{{div col end}}

== Explanatory notes ==
{{Reflist|group=Note}}

== References ==
{{Reflist}}

== Further reading ==
{{Library resources box}}

* {{cite journal|title=The James Webb Space Telescope|author=Jonathan P. Gardner|s2cid=118865272|display-authors=et al.|doi=10.1007/s11214-006-8315-7|journal=Space Science Reviews|volume=123|issue=4 |date=November 2006|pages=484–606|arxiv=astro-ph/0606175|bibcode=2006SSRv..123..485G}} The formal case for JWST science presented in 2006
* {{cite journal|title=Scientific discovery with the James Webb Space Telescope|author=Jason Kalirai|s2cid=85539627|doi=10.1080/00107514.2018.1467648|journal=Contemporary Physics|volume=59|issue=3|date=April 2018|pages=259–290|arxiv=1805.06941|bibcode=2018ConPh..59..251K}} A review of JWST capabilities and scientific opportunities

== External links ==
{{Sister project links|wikt=no|commons=Category:James Webb Space Telescope|v=no|q=no|s=no|n=Hubble Space Telescope successor unveiled by NASA}}
* [https://webbtelescope.org/ Official STScI website]
* [https://jwst.nasa.gov/content/webbLaunch/index.html Official NASA website]
* [https://jwst.fr/ Official French website]

{{James Webb Space Telescope|state=expanded}}
{{Space observatories}}
{{Exoplanet search projects}}
{{NASA navbox}}
{{GSFC}}
{{ESA projects}}
{{Canadian Space Agency}}
{{Future spaceflights}}
{{2021 in space}}

{{Portal bar|Astronomy|Stars|Spaceflight|Outer space|Solar System}}
{{Authority control}}

[[Category:James Webb Space Telescope| ]]
[[Category:2021 in science]]
[[Category:2021 in spaceflight]]
[[Category:European Space Agency space probes]]
[[Category:Exoplanet search projects]]
[[Category:Goddard Space Flight Center]]
[[Category:Infrared telescopes]]
[[Category:NASA programs]]
[[Category:Northrop Grumman spacecraft]]
[[Category:Proposed NASA space probes]]
[[Category:Space program of Canada]]
[[Category:Space telescopes]]
[[Category:Spacecraft using halo orbits]]
[[Category:2021 in French Guiana]]

Yerkes Observatory

2020-12-01T23:02:19Z

Blastr42:

{{Infobox Observatory
| established = 1892<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1896ApJ.....3..215H|title=1896ApJ.....3..215H Page 215|website=adsabs.harvard.edu|bibcode=1896ApJ.....3..215H}}</ref>
|telescope1_name = 40-inch (102 cm)
|telescope1_type = [[Refracting telescope|refractor]] Dedicated 1897
|telescope2_name = 40-inch (102 cm)
|telescope2_type = [[Ritchey–Chrétien telescope|Ritchey–Chrétien reflector]] Since 1968
|telescope3_name = 24-inch (61 cm)
|telescope3_type = [[Cassegrain reflector]] Boller & Chivens
|telescope4_name = 10-inch (25 cm)
|telescope4_type = Cassegrain reflector
|telescope5_name = 7-inch (18 cm)
|telescope5_type = [[Schmidt camera]]
|telescope6_name =12 inch
|telescope6_type = Kenwood Refractor (''former'')
|telescope7_name =23.5 inch
|telescope7_type = The "Two Foot" (''former'')
}}
[[File:Yerkes 40 inch Refractor Telescope-1897.jpg|thumb|1897 photo of the {{convert|40|in|cm|abbr=on}} refractor at the Yerkes Observatory.]]
[[File:The Americana - a universal reference library, comprising the arts and sciences, literature, history, biograhy, geography, commerce, etc., of the world (1903) (14771315644).jpg|thumb|Telescope controls of the {{convert|40|in|cm|abbr=on}} refractor]]

'''Yerkes Observatory''' ({{IPAc-en|ˈ|j|ɜːr|k|iː|z}} {{respell|YUR|keez}}) is an [[Observatory#Astronomical observatories|astronomical observatory]] located in [[Williams Bay, Wisconsin]], U.S.A. It was operated by the [[University of Chicago]] Department of Astronomy and Astrophysics<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/|title=Yerkes Observatory-Home}}</ref><ref name="astro.uchicago.edu">{{Cite web|url=http://astro.uchicago.edu/aboutus/history.php|title=The Department of Astronomy and Astrophysics {{!}} A Bit of History|website=astro.uchicago.edu|access-date=2019-06-16}}</ref> from its founding in 1897 to 2020. Ownership was transferred to the non-profit Yerkes Future Foundation (YFF) in May, 2020.

The observatory, sometimes called "the birthplace of modern astrophysics", was founded in 1892 by astronomer [[George Ellery Hale]] and financed by businessman [[Charles Tyson Yerkes|Charles T. Yerkes]].<ref name="Frentress">{{Cite web |url=https://www.space.com/26858-yerkes-observatory.html |title=Yerkes Observatory: Home of Largest Refracting Telescope |last=Fentress |first=Steve |date=October 2019 |website=Space.com |language=en |access-date=2020-02-23}}</ref>
It represented a shift in the thinking about observatories, from their being mere housing for telescopes and observers, to the early-20th-century concept of observation equipment integrated with laboratory space for [[physics]] and [[chemistry]] analysis.

The observatory's main dome houses a 40-inch (102-cm) diameter doublet lens [[refracting telescope]], the largest refractor ever successfully used for astronomy.<ref>{{cite news
| title=Yerkes Observatory: Home of Largest Refracting Telescope
| url=http://www.space.com/26858-yerkes-observatory.html
| work=Space.com
| author=Elizabeth Howell
| date=August 15, 2014
| accessdate=December 15, 2015
}}</ref> Two smaller domes house 40-inch (102-cm) and 24-inch (61-cm) [[reflecting telescopes]]. There are several smaller telescopes - some permanently mounted - that are primarily used for educational purposes. The observatory also holds a collection of over 170,000 photographic plates.<ref>{{cite web|url=http://astro.uchicago.edu/yerkes/plates/plates.html|archive-url=https://web.archive.org/web/20110514110259/http://astro.uchicago.edu/yerkes/plates/plates.html|url-status=dead|archive-date=2011-05-14|title=Observatory website|publisher=}}</ref>

The Yerkes 40-inch was the largest [[refracting telescope|refracting-type telescope]] in the world when it was dedicated although there had been several larger [[reflecting telescope]]s. During this time, there were many questions about the merits of the various materials used to construct and design telescopes. Another large telescope of this period was the [[Great Melbourne Telescope]], which was also a reflector. In the United States, the [[James Lick telescope|Lick refractor]] had just a few years earlier come online in California with a 91-cm lens.

Prior to its installation, the telescope on its enormous German [[equatorial mount]] was shown at the [[World's Columbian Exposition|Columbian Exhibition]] in Chicago during the time the observatory was under construction.

The observatory was a center for serious astronomical research for more than 100 years. By the 21st century, however, it had reached the end of its research life. The University of Chicago closed the Observatory to the public in October 2018. In November 2019, "an agreement in principle" was announced that the University would transfer Yerkes Observatory to the non-profit Yerkes Future Foundation (YFF). The transfer of ownership took place on May 1, 2020.<ref>{{cite news
| title=Foundation celebrates donation and takes ownership of Yerkes Observatory
| url=https://www.lakegenevanews.net/news/local/foundation-celebrates-donation-and-takes-ownership-of-yerkes-observatory/article_1701caaf-8a68-5e12-89ab-d7d2ab2eb380.html
| work=lakegenevanews.net
| author=Connor Carynski
| date=May 1, 2020
| accessdate=June 9, 2010
}}</ref>

==Telescopes==

[[File:Yerkes Observatory Astro4p6.jpg|thumb|left|[[Alvan Clark]] polishes the big Yerkes objective lens in 1896]]
In the 1860s Chicago became home of the largest telescope in America, the Dearborn 18 1/2 inch refractor.<ref>[http://www.phy.olemiss.edu/Astro/WAG_99_deller.pdf]</ref> Later surpassed by the U.S. Naval Observatory's 26 inch, which would go on to discover the [[moons of Mars]] in 1877, there was an extraordinary increase of larger telescopes in finely furnished observatories in the late 1800s. In the 1890s various forces came together to establish an observatory of art, science, and superlative instruments in Williams Bay, Wisconsin.

The telescope was surpassed by the Harvard College Observatory, 60 inch reflector less than ten years later, although it remained a center for research for decades afterwards. In addition to the large refractor, Yerkes also conducted a great amount of Solar observations.

===Background===
Yerkes Observatory's 40-inch (~102 cm) [[refracting telescope]] has a doublet lens produced by the optical firm [[Alvan Clark & Sons]] and a mounting by the [[Warner & Swasey Company]]. It was the largest refracting telescope used for astronomical research.<ref>{{cite journal
|last=Starr
|first=Frederick
|date=October 1897
|title=Science at the University of Chicago
|journal=Popular Science Monthly
|publisher=D. Appleton and Company
|location=New York
|volume=51
|issue=May to October 1897
|pages=802–803
|url=https://archive.org/stream/appletonspopular51youmrich#page/802/mode/2up
|accessdate=October 25, 2015
|language=English}}</ref><ref name="galaxy196506">{{Cite magazine
|last1=Ley
|first1=Willy
|author=
|last2=Menzel
|first2=Donald H.
|last3=Richardson
|first3=Robert S.
|date=June 1965
|title=The Observatory on the Moon
|department=For Your Information
|url=https://archive.org/stream/Galaxy_v23n05_1965-06#page/n131/mode/2up
|magazine=Galaxy Science Fiction
|pages=132–150
|type=
}}</ref> In the years following its establishment, the bar was set and tried to be exceeded; an even larger demonstration refractor, the [[Great Paris Exhibition Telescope of 1900]], was exhibited at the [[Exposition Universelle (1900)|Paris Universal Exhibition of 1900]].{{r|galaxy196506}}

However, this was not much of a success and was dismantled, and it did not become part of an active University observatory. The mounting and tube for the 40-inch telescope was exhibited at the 1893 [[World's Columbian Exposition]] in Chicago before being installed in the observatory. The grinding of the lens was completed later.<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/history/1893.html|title=Yerkes Observatory - 1893 History of Yerkes Observatory}}</ref>[[File:Yerkes dome construction.jpg|thumb|Three workers on the skeleton of Yerkes Observatory's great dome viewed from the roof. c.1896]]

===The 40-inch aperture refractor===
[[File:Chicago's Great Telescope (3573567148).jpg|thumb|left|The Yerkes Great refractor mounted at the 1893 World's Fair in Chicago]]

The glass blanks for what would become Yerkes Great Refractor were made in Paris, France by Mantois and delivered to [[Alvan Clark & Sons]] in Massachusetts where they were completed.<ref name=":2">{{Cite book|url=https://books.google.com/books?id=qrRz-sXyXJYC&q=yerkes+refractor+at+exhibition&pg=PA51|title=The General History of Astronomy|date=1900|publisher=Cambridge University Press|isbn=9780521242561|language=en}}</ref> Clark then made what would be the largest telescope lens ever crafted and this was mounted to an Equatorial mount made by Warner & Swasey for the observatory.<ref name=":2" /> The telescope had an aperture of 40 inches (~102 cm) and focal length of 19.3 meters, giving it a [[focal ratio]] of f/19.<ref name=":2" />

The lens, an achromatic doublet which has two sections to reduce chromatic aberration, weighed 225 kilograms, and was the last big lens made by Clark before he died in 1897.<ref name=":2" /> Glass lens telescopes had a good reputation compared to speculum metal and silver on glass mirror telescopes, which had not quite proven themselves in the 1890s. For example, the [[Leviathan of Parsonstown]] was a 1.8 meter telescope with a speculum metal mirror, but getting good astronomical results from this technology could be difficult, and another large telescope of this period was the [[Great Melbourne Telescope]] in Australia, also a metal mirror telescope.

[[File:PSM V65 D017 Rumford spectroheliograph attached to the yerkes telescope.png|thumb|Spectroheliograph instrument on the 40-inch refractor in 1904]]
Some of the instruments for the 40-inch refractor (circa 1890s):<ref name=":4">{{Cite journal|url=http://adsabs.harvard.edu/full/1896ApJ.....3..215H|title=1896ApJ.....3..215H Page 215|website=adsabs.harvard.edu|bibcode=1896ApJ.....3..215H|access-date=2019-10-21}}</ref>
*[[Position micrometer|Filar Micrometer]]
*Solar spectrograph
*[[Spectroheliograph]]
*Stellar spectrograph
*Photoheliograph

The 40-inch refractor was modernized in the late 1960s with electronics of the period.<ref name=":9">{{Cite journal|url=http://adsabs.harvard.edu/full/1967AJ.....72.1158O|title=1967AJ.....72.1158O Page 1158|website=adsabs.harvard.edu|bibcode=1967AJ.....72.1158O|access-date=2019-10-22}}</ref> The telescope was painted, the manual controls were removed, and electric operations were added at this time.<ref name=":9" /> This included [[nixie tube]] displays for its operation.<ref name=":9" />

===The 41-inch reflector===
{{main|Yerkes 41-inch reflector}}
In the late 1960s a 40-inch reflecting telescope was added. <ref name=":6">{{Cite web|url=https://www.skyandtelescope.com/astronomy-news/yerkes-on-the-block/|title=Yerkes On the Block|last=Roth|first=Joshua|date=2004-12-15|website=Sky & Telescope|language=en-US|access-date=2019-10-21}}</ref><ref>{{Cite web|url=http://chronicle.uchicago.edu/020815/yerkes.shtml|title=Constructive point of view|website=chronicle.uchicago.edu|access-date=2020-03-03}}</ref> The 41 inch was finished by 1968, with overall installation completed by December 1967 and the optics in 1968.<ref name="Darling">{{Cite web|url=http://www.daviddarling.info/encyclopedia/Y/Yerkes.html|title=Yerkes Observatory|last=Darling|first=David|website=www.daviddarling.info|access-date=2019-10-24}}</ref><ref name="1969BAAS....1..135O Page 135">{{Cite journal|url=http://adsabs.harvard.edu/full/1969BAAS....1..135O|title=1969BAAS....1..135O Page 135|website=adsabs.harvard.edu|bibcode=1969BAAS....1..135O|access-date=2019-10-24}}</ref> While the telescope has a clear aperture of 40-inches, the mirror's physical diameter measures 41-inches leading to the telescope usually being called the "41 inch" to avoid confusion with the 40 inch refractor.<ref name="1969BAAS....1..135O Page 135"/> <ref name="Darling"/><ref name=":7">{{Cite journal|url=http://adsabs.harvard.edu/full/1969BAAS....1..135O|title=1969BAAS....1..135O Page 135|website=adsabs.harvard.edu|bibcode=1969BAAS....1..135O|access-date=2019-10-22}}</ref>
The mirror is made from low-expansion glass.<ref name="adsabs.harvard.edu">{{Cite journal|url=http://adsabs.harvard.edu/full/1967AJ.....72.1158O|title=1967AJ.....72.1158O Page 1158|website=adsabs.harvard.edu|bibcode=1967AJ.....72.1158O|access-date=2020-03-03}}</ref> The glass used was CER-VII-R.<ref name="adsabs.harvard.edu"/>

The launch instruments for the 41 inch reflector included:<ref name=":7" />

* Image tube spectrograph
* photoelectric photometer
* photoelectric spectrophotometer

The 40-inch reflector is of the [[Ritchey–Chrétien telescope|''Ritchey''-''Chretien'']] optical design.<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1969PASP...81..254K|title=1969PASP...81..254K Page 254|website=adsabs.harvard.edu|bibcode=1969PASP...81..254K|access-date=2019-10-24}}</ref> The 41-inch helped pioneer the field of adaptive optics.<ref>{{cite journal|title=Field tests of the Wavefront Control Experiment|journal=Adaptive Optics in Astronomy|date=31 May 1994|doi=10.1117/12.176024|s2cid=119806080|url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/2201/1/Field-tests-of-the-Wavefront-Control-Experiment/10.1117/12.176024.short}}</ref>

===Additional instruments and equipment===
[[File:RitcheyTelescope.jpg|thumb|The old Yerkes 24 inch (2 foot telescope) reflecting telescope, now in a museum]]
[[File:EB1911 Telescope - Fig. 19. Bruce Telescope, Yerkes Observatory.png|thumb|Diagram of the Bruce astrograph]]
A 12 inch refractor was moved to Yerkes from [[Kenwood Astrophysical Observatory|Kenwood Observatory]] in the 1890s.<ref name=":4"/>
Two other telescopes planned for the observatory in the 1890s were a 12-inch aperture refractor and a 24-inch reflecting telescope.<ref name=":4" /> There was a [[heliostat]] mirror and a meridian room for a [[transit instrument]].<ref name=":4" />

A two-foot aperture reflecting telescope was manufactured at the observatory itself.<ref name=":10">{{Cite journal|url=http://adsabs.harvard.edu/full/1901ApJ....14..217R|title=1901ApJ....14..217R Page 217|website=adsabs.harvard.edu|bibcode=1901ApJ....14..217R|access-date=2019-10-22}}</ref> The clear aperture of the telescope was actually 23.5 inches.<ref name=":10" /> The [[glass blank]]s were cast in France by Saint Gobain Glass Works, and then were figured (polished into telescopic shape) at the Yerkes Observatory.<ref name=":10" /> The 'Two foot telescope' used a roughly seven foot long skeleton truss made of aluminum.<ref>{{Cite web|url=http://articles.adsabs.harvard.edu/full/gif/1901ApJ....14..217R/0000225.000.html|title=1901ApJ....14..217R Page 225|website=articles.adsabs.harvard.edu|access-date=2019-10-22}}</ref>

At one point the Observatory had an [[IBM 1620]] computer, which it used for three years.<ref name=":5">{{Cite journal|url=http://adsabs.harvard.edu/full/1967AJ.....72.1158O|title=1967AJ.....72.1158O Page 1158|website=adsabs.harvard.edu|bibcode=1967AJ.....72.1158O|access-date=2019-10-21}}</ref> This was replaced with an [[IBM 1130]] computer in the 1960s.<ref name=":5" />

A Microphotometer was built by Gaertner Scientific Corporation, which was delivered in February 1968 to the observatory.<ref>{{Cite web|url=http://www.daviddarling.info/encyclopedia/Y/Yerkes.html|title=Yerkes Observatory|last=Darling|first=David|website=www.daviddarling.info|access-date=2020-03-03}}</ref><ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1969BAAS....1..135O|title=1969BAAS....1..135O Page 135|website=adsabs.harvard.edu|bibcode=1969BAAS....1..135O|access-date=2020-03-03}}</ref>

Later, there was another 24 inch reflecting telescope by [[Boller and Chivens|Boller & Chivens.]]<ref name=":6" /><ref>{{Cite web|url=http://www.daviddarling.info/encyclopedia/Y/Yerkes.html|title=Yerkes Observatory|last=Darling|first=David|website=www.daviddarling.info|access-date=2019-10-22}}</ref> This was contracted in the early 1960s under direction of observatory director [[W. Albert Hiltner]].<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1963AJ.....68..756M|title=1963AJ.....68..756M Page 756|website=adsabs.harvard.edu|bibcode=1963AJ.....68..756M|access-date=2019-10-22}}</ref> This telescope was installed in one of the smaller Yerkes domes, and it is known to have been used for visitor programs.<ref>{{Cite web|url=https://bollerandchivens.com/?p=1848|title=24 Inch (.61 Meters) Telescope for University of Chicago, Yerkes Observatory - Boller and Chivens: A History "Where Precision is a Way of Life" - Boller and Chivens were makers of Telescopes and Precision Instruments|website=bollerandchivens.com|access-date=2019-10-24}}</ref> This was a design by Boller & Chivens with Cassegrain optical setup, with a 24 inch (61 cm) clear aperture and is on an off-axis equatorial mount.<ref>{{Cite web|url=http://bollerandchivens.com/?p=2492|title=24-Inch (.61 meter) Telescope Specifications - Boller and Chivens: A History "Where Precision is a Way of Life" - Boller and Chivens were makers of Telescopes and Precision Instruments|website=bollerandchivens.com|access-date=2019-10-24}}</ref>

A 7-inch (18 cm) diameter aperture [[Schmidt camera]] was also at Yerkes Observatory.<ref>{{Cite web|url=http://photoarchive.lib.uchicago.edu/db.xqy?one=apf2-08781.xml|title=Yerkes Observatory : Photographic Archive : The University of Chicago|website=photoarchive.lib.uchicago.edu|access-date=2019-10-24}}</ref>

The Snow Solar Telescope was first established at Yerkes Observatory, and then later moved in 1904 out to California.<ref name=":13" /> A major difficulty of these telescopes was dealing with heat from the Sun, and it was built horizontally, but lead to a vertical solar tower design afterwards.<ref name=":13" /> Solar tower telescopes would be a popular style for solar observatories in the 20th century, and are still used in the 21st century to observe the Sun.

Another instrument was the Bruce photographic telescope.<ref name=":15">{{Cite journal|url=http://adsabs.harvard.edu/full/1905ApJ....21...35B|title=1905ApJ....21...35B Page 35|website=adsabs.harvard.edu|bibcode=1905ApJ....21...35B|access-date=2019-11-02}}</ref> The telescope had two objective lens for photography, one doublet of 10 inches aperture and another of 6.5 inches; in addition there is a 5-inch guide scope for visual viewing.<ref name=":15" /> The telescope was constructed from funds donated in 1897.<ref name=":15" /> The telescope was mounted on custom designed equatorial, the result of collaboration between Yerkes and Warner & Swasey, especially designed to offer an uninterrupted tracking for long image exposures.<ref name=":15" /> The images were taken on glass plates about a foot on each side.<ref name="auto2">{{Cite web|url=http://www.artdeciel.com/astrophotography-camera-detail.aspx?Camera_ID=254|title=Famos Astrograph/Camera Detail|website=www.artdeciel.com|access-date=2019-11-02}}</ref>

The Bruce astrograph lenses were made by Brashear with Mantois of Paris glass blanks, and the lenses were completed by the year 1900.<ref name=":15" /> The overall telescope was not completed until 1904, where it was installed in its own dome at Yerkes.<ref name="auto2"/>

The astronomer [[Edward Emerson Barnard]]'s work with the Bruce telescope lead to the publication of a sky atlas using images taken with the instrument, and also a catalog of [[dark nebula]] known as the [[Barnard Catalogue|Barnard catalog]].<ref>{{Cite book|url=https://books.google.com/books?id=wyWjVWYWoO8C&q=bruce+astrograph+yerkes&pg=PA396|title=Observing and Cataloguing Nebulae and Star Clusters: From Herschel to Dreyer's New General Catalogue|last=Steinicke|first=Wolfgang|date=2010-08-19|publisher=Cambridge University Press|isbn=9781139490108|language=en}}</ref>

== Dedication ==
[[File:Yerkes Observatory Astro4p3.jpg|thumb|left|Group photo from the dedication in October 1897]]
The Observatory was dedicated on October 21, 1897 and there was a large party with University, astronomers, and scientists.<ref name="chronicle.uchicago.edu">{{Cite web|url=http://chronicle.uchicago.edu/970320/yerkes.shtml|title=Yerkes Observatory: A century of stellar science|website=chronicle.uchicago.edu|access-date=2019-10-21}}</ref>

Before the dedication a conference of astronomers and astrophysicists was hosted at Yerkes Observatory, and took place on October 18–20, 1897.<ref>{{Cite web|url=https://had.aas.org/resources/aashistory/early-meetings/1897-1906|title=Meetings of the AAS: 1897-1906 {{!}} Historical Astronomy Division|website=had.aas.org|access-date=2019-10-22}}</ref> This is noted as a precursor to the founding of the [[American Astronomical Society]]

Although dedicated in 1897, it was founded in 1892.<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1896ApJ.....3..215H|title=1896ApJ.....3..215H Page 215|website=adsabs.harvard.edu|bibcode=1896ApJ.....3..215H|access-date=2020-03-03}}</ref> Also, astronomical observations had started in the summer of 1897 before the dedication.<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1947PA.....55..413S|title=1947PA.....55..413S Page 413|website=adsabs.harvard.edu|bibcode=1947PA.....55..413S|access-date=2019-10-30}}</ref>

==Research & Observations==
[[File:Yerkes Messier 51 Canum Venaticorum 1902.jpg|thumb|A photo of the [[Whirlpool Galaxy|Messier 51 galaxy]] taken on June 3, 1902 at the Yerkes Observatory]]
[[File:Annual report of the Board of Regents of the Smithsonian Institution (1901) (17813060474).jpg|thumb|George Ritchey image of what he called the ''Great Neubla in Cygnus'' (In modern times the [[Veil Nebula]]); taken with the two-foot reflecting telescope with 3 hours exposure]]
Research conducted at Yerkes in the last decade{{when|date=August 2018}} includes work on the [[interstellar medium]], [[globular cluster]] formation, [[infrared]] astronomy, and [[near-Earth objects]]. Until recently the [[University of Chicago]] also maintained an engineering center in the observatory, dedicated to building and maintaining scientific instruments. In 2012 the engineers completed work on the High-resolution Airborne Wideband Camera (HAWC), part of the [[Stratospheric Observatory for Infrared Astronomy]] (SOFIA).<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/hawc.html|title=Yerkes Observatory-R & D-HAWC}}</ref>
Researchers also use the Yerkes collection of over 170,000 archival photographic plates that date back to the 1890s.<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/plates/plates.html|title=The Yerkes Observatory Photographic Plates}}</ref> The past few years have seen astronomical research largely replaced by educational outreach and astronomical tourism activities.

In June 1967, Yerkes Observatory hosted the to-date largest meeting of the American Astronomical Society, with talks on over 200 papers.<ref name=":5" />

The ''Yerkes spectral classification'' (aka ''MKK'' system) was a system of stellar spectral classification introduced in 1943 by [[William Wilson Morgan]], [[Philip Childs Keenan|Philip C. Keenan]], and [[Edith Kellman]] from Yerkes Observatory.<ref>{{cite book|title=An atlas of stellar spectra, with an outline of spectral classification|last1=Morgan|first1=William Wilson|last2=Keenan|first2=Philip Childs|last3=Kellman|first3=Edith|date=1943|publisher=The University of Chicago Press|bibcode=1943assw.book.....M|oclc=1806249}}</ref> This two-dimensional ([[temperature]] and [[luminosity]]) classification scheme is based on [[spectral line]]s sensitive to stellar temperature and [[surface gravity]], which are related to luminosity (the ''Harvard classification'' is based on surface temperature). Later, in 1953, after some revisions of lists of standard stars and classification criteria, the scheme was named the ''Morgan–Keenan classification'', or ''MK.''<ref name="ref_MK">{{cite journal|last1=Morgan|first1=William Wilson|last2=Keenan|first2=Philip Childs|date=1973|title=Spectral Classification|journal=Annual Review of Astronomy and Astrophysics|volume=11|pages=29–50|bibcode=1973ARA&A..11...29M|doi=10.1146/annurev.aa.11.090173.000333}}</ref>

Research work of the Yerkes Observatory has been cited over 10,000 times.<ref>{{Cite web|url=https://legacy.aas.org/files/aas-donahue-yerkes-letter.pdf|title=aas-donahue-yerkes-letter|last=|first=|date=July 10, 2018|website=AMERICAN ASTRONOMICAL SOCIETY|access-date=2020-03-03}}</ref>

In 1899, observations of Neptune's moon Triton were published, with data recorded using the Warner & Swasey micrometer.<ref name=":14">{{Cite book|url=https://books.google.com/books?id=0pURAAAAYAAJ&q=asteroids+discovered+with+40+inch+yerke&pg=PA197|title=The Astronomical Journal|date=1900|publisher=American Institute of Physics.|language=en}}</ref> In 1898 and 1899, Neptune was at opposition.<ref name=":14" />

In 1906, a star catalog of over 13,600 stars was published.<ref name=":12">{{Cite web|url=https://www.space.com/26858-yerkes-observatory.html|title=Yerkes Observatory: Home of Largest Refracting Telescope|last1=Science|first1=Elizabeth Howell 2014-08-16T02:26:07Z|last2=Astronomy|website=Space.com|language=en|access-date=2019-10-24}}</ref> Also, there was some important work on Solar research in the early years, which was of interest to Hale.<ref name=":12" /> He went on to the Snow Solar Telescope at Mount Wilson in California.<ref name=":13">{{Cite web|url=https://www.mtwilson.edu/vt-snow-solar-telescope/|title=VT Snow Solar Telescope|date=2017-01-29|website=Mount Wilson Observatory|language=en-US|access-date=2019-10-24}}</ref> This was first operated at Yerkes and then moved to California.<ref name=":13" />

An example of an asteroid discovered at Yerkes is [[1024 Hale]], provisional designation {{mp|A923 YO|13}}, a carbonaceous background [[asteroid]] from the outer regions of the [[asteroid belt]], approximately {{convert|45|km|mi|abbr=off|sp=us}} in diameter. The asteroid was discovered on 2 December 1923 by Belgian–American astronomer [[George Van Biesbroeck]] at Yerkes Observatory, and it was named for astronomer George Ellery Hale of Yerkes Observatory fame. Some additional examples include [[990 Yerkes]], [[991 McDonalda]], and [[992 Swasey]] around this time; many more minor planets would be discovered at the observatory in the following decades.

==Notable staff and visitors==
[[File:Yerkes Observatory Astro4p7.jpg|thumb|350px|The 40-inch (1.02 m) Refractor backdrops Einstein's visit to the Observatory in May 1921]]

Notable astronomers who conducted research at Yerkes include [[Albert Michelson]],<ref>{{cite journal |last=Gale |first=Henry G. |authorlink=Henry Gale (astrophysicist) |date=July 1931 |title=Albert A. Michelson |url= |journal=The Astrophysical Journal |volume=74 |issue=1 |pages=1–9 |doi=10.1086/143320 |accessdate= }}</ref> [[Edwin Hubble]] (who did his graduate work at Yerkes and for whom the [[Hubble Space Telescope]] was named), [[Subrahmanyan Chandrasekhar]] (for whom the [[Chandra X-ray Observatory|Chandra Space Telescope]] was named), Russian-American astronomer [[Otto Struve]],<ref name="astro.uchicago.edu"/> Dutch-American astronomer [[Gerard Kuiper]] (noted for theorizing the [[Kuiper belt]], home to dwarf planet Pluto),
[[Nancy Grace Roman]], NASA's first Chief of Astronomy (who did her graduate work at Yerkes), and the twentieth-century popularizer of astronomy [[Carl Sagan]].

In May 1921, [[Albert Einstein]] visited the Yerkes Observatory.<ref>{{Cite web|url=https://atthelakemagazine.com/einstein-yerkes-observatory/|title=The Day Einstein Came to Town|date=2013-12-20|website=At The Lake Magazine|language=en-US|access-date=2019-10-21}}</ref>

Directors of Yerkes Observatory:<ref>{{Cite web|url=https://astro.uchicago.edu/aboutus/history.php|title=The Department of Astronomy and Astrophysics {{!}} A Bit of History|website=astro.uchicago.edu|access-date=2020-03-03}}</ref>
*2012 - 2018 Doyal ''Al'' Harper (2nd time)
*2001 - 2012 Kyle M. Cudworth
*1989 - 2001 Richard G. Kron
*1982 - 1989 Doyal ''Al'' Harper
*1974 - 1982 Lewis M. Hobbs
*1972 - 1974 William Van Altena
*1966 - 1972 C. Robert O'Dell
*1963 - 1966 [[William Hiltner]]
*1960 - 1963 [[William W. Morgan]]
*1957 - 1960 [[Gerard P. Kuiper]] (2nd time)
*1950 - 1957 [[Bengt Stromgren]]
*1947 - 1950 Gerard P. Kuiper
*1932 - 1947 [[Otto Struve]]
*1903 - 1932 [[Edwin B. Frost]]
*1897 - 1903 [[George Ellery Hale]]

==The 2005 proposed development and preservation initiative==
[[File:Grandest century in the world's history; containing a full and graphic account of the marvelous achievements of one hundred years, including great battles and conquests; the rise and fall of nations; (14781534012).jpg|thumb|A year 1900 book makes note of the Observatory]]
In March 2005, the University of Chicago announced plans to sell the observatory and its land on the shore of [[Geneva Lake]]. Two purchasers had expressed an interest: Mirbeau, an East Coast developer that wanted to build luxury homes, and [[Aurora University]], which has a campus straddling the Williams Bay property. The Geneva Lake Conservancy, a regional conservation and [[land trust]] organization, maintained that it was critical to save the historic Yerkes Observatory structures and telescopes for education and research, as well as to conserve the rare undeveloped, wooded lakefront and deep [[forest]] sections of the {{convert|77|acre|m2|adj=on|abbr=out|sp=us}} site. On June 7, 2006, the University announced it would sell the facility to Mirbeau for US$8 million with stipulations to preserve the observatory, the surrounding {{convert|30|acre|m2|abbr=on}}, and the entire shoreline of the site.<ref>{{Cite web|url=http://www-news.uchicago.edu/releases/06/060607.yerkes.shtml|title=Agreement provides for preservation of historic Yerkes Observatory|website=www-news.uchicago.edu|access-date=2019-06-16}}</ref>

Under the Mirbeau plan, a 100-room resort with a large [[spa]] operation and attendant parking and support facilities was to be located on the {{convert|9|acre|m2|adj=on|abbr=out|sp=us}} virgin wooded Yerkes land on the lakeshore—the last such undeveloped, natural site on Geneva Lake's {{convert|21|mi|km|abbr=off|adj=on|sp=us}} shoreline. About 70 homes were to be developed on the upper Yerkes property surrounding the historic observatory. These grounds had been designed more than 100 years previously by [[John Charles Olmsted]], the nephew and adopted son of famed [[landscape architect]] [[Frederick Law Olmsted]]. Ultimately, Williams Bay's refusal to change the zoning from education to residential caused Mirbeau to abandon its development plans.

In view of the public controversy surrounding the development proposals, the university suspended these plans in January 2007.<ref>{{cite web|url=http://www.chicagotribune.com/business/chi-0701040304jan04,0,3146579.story?coll=chi-business-hed|title=Topic Galleries - chicagotribune.com|publisher=}}</ref> The university's department of astronomy and astrophysics then formed a study group, including representatives from the faculty and observatory and a wide range of other involved parties, to plan for the operation of a regional center for science education at the observatory.<ref>{{Cite web|url=http://www-news.uchicago.edu/releases/07/070228.yerkes.shtml|title=Yerkes Study Group formed to consider observatory's future|website=www-news.uchicago.edu|access-date=2019-06-16}}</ref> The study group began its work in February 2007 and issued its final report November 30, 2007.<ref name="report">{{cite web|url=http://astro.uchicago.edu/yerkes/ysg/YSG_Final_Report.pdf|title=Final Report of the Yerkes Study Group, November 30, 2007, Yerkes Science Center: Options for Management and Funding|publisher=}}</ref>
The report recommended creating a formal business plan to ensure the financial viability of the proposed science education center, establishing ownership of the proposed center before initiating plans for creating it, and forming a partnership between the University of Chicago and local interests to plan for the center. It also suggested that some lakefront and woods parcels could be sold for residential development.<ref name="report"/>

==Closure==
[[File:Yerkes Observatory 2009 Oct.jpg|thumb|Yerkes in 2009]]
In March 2018, the University of Chicago announced that it would no longer operate the observatory after October 1, 2018, and would be seeking a new owner.<ref>Scott Williams. "[http://www.lakegenevanews.net/news/yerkes-observatory-closing-after-years-on-lakefront/article_cc29cbf9-12a7-5fd6-abc1-357ce8f3bd6f.html Yerkes Observatory closing after 100 years on lakefront]".{{subscription required}} ''Lake Geneva Regional News'', March 7, 2018.</ref> In May 2018, the Yerkes Future Foundation, a group of local residents, submitted an expression of interest to the University of Chicago with a proposal that would seek to maintain public access to the site and continuation of the educational programs.<ref>{{Cite web|url=https://www.chicagomaroon.com/article/2018/5/11/new-group-submits-proposal-keep-yerkes-open/|title=New Group Submits Proposal to Keep Yerkes Open|website=www.chicagomaroon.com|language=en|access-date=2018-09-30}}</ref> Transfer of operation to a successor operator was not arranged by the end of August, and the facility was closed to the general public on October 1. Some research activities continued at the Observatory, including access and use of the extensive historical glass plate archives at the site. Yerkes education and outreach staff formed a nonprofit organization – GLAS – to continue their programs at another site after the closing.<ref>{{Cite web|url=https://www.glaseducation.org/|title=GLAS EDUCATION|website=GLAS EDUCATION|language=en|access-date=2018-09-30}}</ref>

In May 2019, the University continued to negotiate with interested parties on Yerkes' future, primarily with the Yerkes Future Foundation. It was announced in November 2018 that a sticking point has been the need to include the Yerkes family in the discussions. Mr. Yerkes' agreement in making his donation to the University transfers ownership “To have and to hold unto the said Trustees [of the University of Chicago] and their successors so long as they shall use the same for the purpose of astronomical investigation, but upon their failure to do so, the property hereby conveyed shall revert to the said Charles T. Yerkes or his heirs at law, the same as if this conveyance had never been made.” <ref>{{Cite web|url=https://www.chicagomaroon.com/article/2019/5/8/original-bequest-letter-for-yerkes-observatory-hold/|title=Original bequest letter for Yerkes Observatory holds up its future|website=The Chicago Maroon|language=en|access-date=2019-05-28}}</ref>

For the closing, there is a new gate with a sign that reads "Facilities Closed To The Public" since October 1, 2018.<ref>{{Cite web|url=https://www.lakegenevanews.net/news/yerkes-like-a-cemetery-one-year-after-shutdown/article_f1a6e0c0-d167-5edc-a761-5362f72e4639.html|title=Yerkes like a 'cemetery' one year after shutdown|last=swilliams@lakegenevanews.net|first=Scott Williams|website=Lake Geneva News|language=en|access-date=2019-10-21}}</ref>

== Gargoyle sculptures, location, and landscaping ==
[[File:Yerkesgargoyle.jpg|thumb|upright|A Yerkes Gargoyle sculpture on the Observatory building]]
The Observatory grounds and buildings are renowned for more than the Great Refractor, but also sculptures and architecture.<ref name=":3">{{Cite web|url=https://www.skyandtelescope.com/astronomy-news/not-quite-closing-yerkes-observatory/|title=The Not-Quite Closing of Yerkes Observatory|date=2018-03-16|website=Sky & Telescope|language=en-US|access-date=2019-10-03}}</ref> In addition, the landscaping is also famed for its design work by Olmstead.<ref name=":0" /> The observatory building was designed by architect Henry Ives Cobb, and has been referred to as being in the [[Beaux-Arts architecture|Beux Arts]] style.<ref name=":8">{{Cite web|url=https://www.wisconsinhistory.org/Records/Property/HI81162|title=OBSERVATORY DR {{!}} Property Record|date=2012-01-01|website=Wisconsin Historical Society|access-date=2019-10-22}}</ref> The building is noted for its blend of styles and rich ornamentation featuring a variety of animal and mythological designs.<ref name=":8" />

On the building there are various carvings including Lion gargoyle designs.<ref>{{Cite web|url=https://hdl.huntington.org/digital/collection/p15150coll2/id/38/|title=CONTENTdm|website=hdl.huntington.org|access-date=2019-10-03}}</ref><ref name=":3" /> There are also sculptures to represent various people that oversaw or supported construction of the telescope and the facility.<ref name="Cruikshank">{{Cite book|url=https://books.google.com/books?id=BJtIDwAAQBAJ&q=yerkes+gargoyles&pg=PA170|title=Discovering Pluto: Exploration at the Edge of the Solar System|last1=Cruikshank|first1=Dale P.|last2=Sheehan|first2=William|date=2018-02-27|publisher=University of Arizona Press|isbn=9780816534319|language=en}}</ref> The location is noted for a good and pleasant location by Lake Geneva.<ref name="Cruikshank"/> Although it does not have a high-altitude as preferred by modern observatories, it does have a lot of good weather, and was a considerable distance from the light and pollution of the City of Chicago.<ref>{{Cite journal|last=Aut|first=Kron Richard author|date=2018-07-06|title=The scientific legacy of Yerkes Observatory|journal=Physics Today|url=https://physicstoday.scitation.org/do/10.1063/PT.6.4.20180706a/abs/|language=EN|doi=10.1063/PT.6.4.20180706a}}</ref>

In 1888, Williams Bay had railway terminal added by [[Chicago & North Western Railroad]]; this provided access from the City of Chicago, and is one factor that increased the site's development in the following decades.<ref>{{Cite web|url=https://www.lakegenevanews.net/news/williams-bay-centennial-a-century-in-story-and-pictures/article_0bb078e8-7a4a-5d8d-a96d-cd1e30a1d300.html|title=Williams Bay Centennial: A century in story and pictures|last=cschultz@lakegenevanews.net|first=Chris Schultz|website=Lake Geneva News|language=en|access-date=2019-10-21}}</ref>

The editorial offices for [[The Astrophysical Journal]] were located at Yerkes Observatory until the 1960s.<ref name="chronicle.uchicago.edu"/>

The landscape was designed by the same firm that did [[New York Central Park|New York Central park]], the firm of Frederick Law Olmsted, and the grounds were noted at one point for having multiple state record trees.<ref name=":11">{{Cite web|url=https://dnr.wi.gov/topic/ForestManagement/EveryRootAnAnchor/documents/091-YerkesObservatory.pdf|title=The Trees at Yerkes Observatory|last=|first=|date=|website=|access-date=}}</ref> The tree plan design was developed in the 1910s under design from the Olmstead firm and with support of the observatory Director; the grounds included the following types of trees at that time: [[white fir]], [[Cladrastis kentukea|yellowwood tree]], [[Golden-rain tree|golden rain tree]], [[European beech]], fernleaf beech, Japanese [[pagoda tree]], [[littleleaf linden]], [[Kentucky coffeetree]], [[Gingko tree|ginkgo]], cut-leaf beeches, and [[chestnut tree]]s.<ref name=":11" />

The original landscape plan was not completed by the 1897 dedication, and there was grading and construction of gravel roads under direction of the Olmstead design as late as 1908.<ref>{{Cite web|url=https://www.lib.uchicago.edu/about/news/yerkes-observatory-photographs-now-online/|title=Yerkes Observatory Photographs Now Online - The University of Chicago Library News - The University of Chicago Library|website=www.lib.uchicago.edu|access-date=2019-10-22}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=nwniAAAAMAAJ&q=Olmstead++yerkes+observatory&pg=PA29|title=University Record|last=Chicago|first=University of|date=1908|publisher=University of Chicago Press|language=en}}</ref>

==Contemporaries on debut of the Great Yerkes Refractor==
<noinclude>
<blockquote class="toccolours" style="text-align:justify; width:40%; float:right; padding: 10px 15px 10px 15px; display:table;">
<center>'''Legend'''</center>
* {{legend2|#F0FFFF|[[Reflector telescope|Reflector (Metal mirror) or unknown]]|border=1px solid #AAAAAA}}
* {{legend2|#CCFFFF|[[Reflector telescope|Glass Reflector (Silver on glass mirror)]]|border=1px solid #AAAAAA}}
* {{legend2| |[[Refractor|Refractor (Lens)]]|border=1px solid #AAAAAA}}
</blockquote>
</noinclude>

A major contemporary for the Yerkes was the well regarded 36-inch Lick refractor in California.<ref name=":16">{{Cite web|url=https://www.nps.gov/parkhistory/online_books/butowsky5/astro4p.htm|title=National Park Service: Astronomy and Astrophysics (Yerkes Observatory)|website=www.nps.gov|access-date=2019-11-03}}</ref> The Yerkes, although just 4 inches in aperture larger, meant an increase of 23% in light-gathering ability.<ref name=":16" /> Both telescopes had achromatic doublets by [[Alvan Clark]].

Over the 19th century saw a transition in large telescope construction from refractor type to reflector type, with metal-film-coated glass mirrors tending to be used instead of difficult, older-style metal mirrors. The Yerkes was perhaps the greatest of the [[great refractor]]s, the largest astronomical instrument in the traditional style of the 19th century refractor-based observatories.

The Yerkes was not only the largest refractor, but was tied for being the largest telescope in the world with Paris Observatory reflector (48 inch, 122 cm) when it became operational in 1896.<ref name=page250>{{Cite web|url=http://articles.adsabs.harvard.edu/full/gif/1914Obs....37..245H/0000250.000.html|title=1914Obs....37..245H Page 250|accessdate=September 8, 2019}}</ref>

{| class="wikitable sortable" style="font-size:95%;"
! Name/Observatory
! class="unsortable" |[[Aperture]] cm (in)
! [[Telescope|Type]]
! Location
! Extant or Active
|- style="background:#F0FFFF"
|[[Leviathan of Parsonstown]] || 183 cm (72″) || [[Speculum metal|reflector – metal]] || [[Birr Castle]]; [[Ireland]] || 1845–1908*
|- style="background:#F0FFFF"
| [[Great Melbourne Telescope]]<ref name="stjarnhimlen.se">{{Cite web|url=http://stjarnhimlen.se/bigtel/LargestTelescope.html|title=Largest optical telescopes of the world|website=stjarnhimlen.se|accessdate=September 8, 2019}}</ref> || 122 cm (48″) || [[Speculum metal|reflector – metal]] || [[Melbourne Observatory]], Australia || 1878
|-style="background:#CCFFFF"
| National Observatory, Paris || 120 cm (47″) || [[Silver on glass|reflector – glass]] || Paris, France || 1875–1943<ref name=page250/>
|- style="background:#DAF7A6"
| Yerkes Observatory<ref name="ReferenceA">http://astro.uchicago.edu/vtour/40inch/</ref> || 102 cm (40″) || achromat || [[Williams Bay, Wisconsin]], [[United States|USA]] || 1897
|-style="background:#CCFFFF"
| Meudon Observatory 1m<ref name="auto1">{{Cite book|url=https://books.google.com/books?id=tEMiAQAAIAAJ&q=meudon+100+cm+reflector&pg=PA584|title=Popular Astronomy|date=1911|publisher=Goodsell Observatory of Carleton College|language=en}}</ref>|| 100 cm (39.4″) || reflector-glass || Meudon Observatory/ Paris Observatory || 1891 <ref name="auto3">{{Cite web|url=https://www.obspm.fr/le-telescope-de-1-metre.html?lang=en|title=Le télescope de 1 mètre - Observatoire de Paris - PSL Centre de recherche en astronomie et astrophysique|website=www.obspm.fr|access-date=2020-03-03}}</ref>
|-
|[[James Lick telescope]], [[Lick Observatory]] || 91 cm (36″) || achromat || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1888
|- style="background:#CCFFFF"
| [[Crossley telescope|Crossley Reflector]]<ref name="ucolick.org">{{Cite web|url=http://www.ucolick.org/public/telescopes/crossley.html|title=Mt. Hamilton Telescopes: CrossleyTelescope|website=www.ucolick.org|accessdate=September 8, 2019}}</ref> (Lick Observatory) || 91.4 cm (36″) || [[Silver on glass|reflector – glass]] || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1896
|}
<nowiki>*</nowiki>Note the Leviathan of Parsonstown was not used after 1890

{|
|[[File:Lick-Refraktor 3130169128.jpg|thumb|The Lick telescope in California was 91 cm aperture and debuted in 1888]]
|[[File:Grande Lunette de l'Observatoire de Meudon.jpg|thumb|The ''Grande Lunette'' of Meudon Observatory (France), was double refractor with both a 83 cm and 62 cm on one shaft and came online in 1891]]
|[[File:Berlin Treptow Archenhold Sternwarte.jpg|thumb|Germany's ''Himmelskanone'' did away with a dome (The telescope tube extends above the observatory in this image) but was quite long, also debuting 1896 like Yerkes]]
|}
{{clear}}

Understanding atmosphere and trends of telescope building of the late 19th century puts the choice of a large refactor in perspective. Although there were some very large reflectors, the [[Speculum metal|speculum mirrors]] they relied on reflected about 2/3 of the light and had high upkeep. A major breakthrough came in the middle of the 19th century with a technique for coating glass with a metal film. This process ([[Silvering|silver on glass]]) eventually lead to some bigger glass reflectors. Silvering has its own issues, in that coating must be reapplied usually every 2 years or so depending on conditions, and also it must be done very thinly so as to not effect the optical properties of the mirror.

A large glass reflector (122 cm diameter glass mirror) was established in Paris by 1876, but problems with figuring of that mirror meant that the Paris Observatory's 122 cm telescope was not used and did not have a good reputation for viewing.<ref name=":1">{{Cite book|url=https://books.google.com/books?id=bWRbAQAAQBAJ&q=paris+122+cm+reflector&pg=PT137|title=The Great Melbourne Telescope|last=Gillespie|first=Richard|date=2011-11-01|publisher=Museum Victoria|isbn=9781921833298|language=en}}</ref> The potential of metal coated glass became more apparent A.A. Common's 36 inch reflecting telescope by 1878.<ref name=":1" /> (this won an astrophotography award)

The Warner and Swasey equatorial mount was shown in Chicago at the 1893 Colombia Exhibition, before it was moved to the Observatory.<ref name=":2"/>

;Largest telescopes (all types) in 1910)
{| class="wikitable sortable" style="font-size:95%;"
! Name/Observatory
! class="unsortable" |[[Aperture]] cm (in)
! [[Telescope|Type]]
! Location
! Extant or Active
|-style="background:#CCFFFF"
| Harvard 60-inch Reflector<ref name="auto">{{Cite web |url=https://query.nytimes.com/gst/abstract.html?res=9A0CE3DC143AE733A25755C0A9629C946497D6CF |title=New York Times "NEW HARVARD TELESCOPE.; Sixty-Inch Reflector, Biggest in the World, Being Set Up. "April 6, 1905, Thursday", Page 9 |access-date=February 10, 2017 |archive-url=https://web.archive.org/web/20160810055322/http://query.nytimes.com/gst/abstract.html?res=9A0CE3DC143AE733A25755C0A9629C946497D6CF |archive-date=August 10, 2016 |url-status=live }}</ref> || 1.524 m (60″) || [[Silver on glass|reflector – glass]] || [[Harvard College Observatory]], USA || 1905–1931
|-style="background:#CCFFFF"
| [[Mount Wilson Observatory|Hale 60-Inch Telescope]] || 1.524 m (60″) || [[Silver on glass|reflector – glass]] || [[Mt. Wilson Observatory]]; [[California]] || 1908
|-style="background:#CCFFFF"
| National Observatory, Paris || 122 cm (48″) || [[Silver on glass|reflector – glass]] || Paris, France || 1875–1943<ref name=page250/>
|- style="background:#F0FFFF"
| [[Great Melbourne Telescope]]<ref name="stjarnhimlen.se"/> || 122 cm (48″) || [[Speculum metal|reflector – metal]] || [[Melbourne Observatory]], Australia || 1878
|- style="background:#DAF7A6"
| Yerkes Observatory<ref name="ReferenceA"/> || 102 cm (40″) || achromat || [[Williams Bay, Wisconsin]], [[United States|USA]] || 1897
|-
|-style="background:#CCFFFF"
| Meudon Observatory 1m<ref name="auto1"/>|| 100 cm (39.4″) || reflector-glass || Meudon Observatory/ Paris Observatory || 1891 <ref name="auto3"/>
|-
|[[James Lick telescope]], [[Lick Observatory]] || 91 cm (36″) || achromat || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1888
|- style="background:#CCFFFF"
| [[Crossley telescope|Crossley Reflector]]<ref name="ucolick.org"/> (Lick Observatory) || 91.4 cm (36″) || [[Silver on glass|reflector – glass]] || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1896
|}

==Legacy==
[[File:Titan in true color.jpg|thumb|The Atmosphere of Saturn's moon Titan (''pictured'') was discovered by Kuiper while working at the Yerkes Observatory—a moon that would later be visited by Voyager 1 and also the Cassini-Huygens spacecraft.]]
By 1905, the largest telescope in the World was the Harvard 60-inch Reflector ( 1.524 m 60″) at [[Harvard College Observatory]], USA.<ref name="auto"/> Then in 1908, [[Mount Wilson Observatory]] matched that size with a 60-inch reflector of their own, and throughout the 20th century, increasingly larger reflectors would be established, aided also by refinements to mirror technology{{mdash}} vapor-deposited aluminum on low-thermal expansion glass, pioneered for the 200 inch (5 meter) Hale telescope of 1948.<ref>{{Cite web|url=http://www.astro.caltech.edu/palomar/about/telescopes/hale.html|title=The 200-inch Hale Telescope|website=www.astro.caltech.edu}}</ref>

In the latter years of the 20th century, space observatories also marked a major advance, and somewhat less than a century after Yerkes, the Hubble Space Telescope, with a 2.4 meter reflector, was launched. Small refractors remain popular for astronaut photography, although issues with chromatic aberration were never really entirely solved for the lens. (Isaac Newton had solved this with the reflecting design, although the refactors are not without their merits.)

The renaissance-esque grounds<ref>{{Cite web|url=http://www-news.uchicago.edu/releases/06/060607.yerkes.shtml|title=Agreement provides for preservation of historic Yerkes Observatory|website=www-news.uchicago.edu|access-date=2020-03-03}}</ref> and architecture, murals, and statues of the premiere 19th century great observatories, with their extraordinary great telescopes; the Yerkes facility was described as "castle-like".<ref>{{Cite web|url=https://www.skyandtelescope.com/astronomy-news/not-quite-closing-yerkes-observatory/|title=The Not-Quite Closing of Yerkes Observatory|date=2018-03-16|website=Sky & Telescope|language=en-US|access-date=2019-10-02}}</ref> For example, the Yerkes Observatory was built on a 77-acre grounds, with artistically designed landscaping.<ref name="Science">{{Cite web|url=https://www.space.com/26858-yerkes-observatory.html|title=Yerkes Observatory: Home of Largest Refracting Telescope|last1=Science|first1=Elizabeth Howell 2014-08-16T02:26:07Z|last2=Astronomy|website=Space.com|language=en|access-date=2019-10-02}}</ref><ref name=":0" /> The visually remarkable extremely long tubes and elaborate domes and mounts provided an egg of knowledge that astronomers and the public flocked to for knowledge about the stars. The Yerkes grounds have landscaping designed by Olmstead, for example.<ref name=":0">{{Cite web|url=http://www-news.uchicago.edu/releases/06/060607.yerkes.shtml|title=Agreement provides for preservation of historic Yerkes Observatory|website=www-news.uchicago.edu|access-date=2019-10-02}}</ref>

Great advancements such as [[astrophotography]] and the discovery of nebulas and different types of stars provided a major advance in this period. The importance of finely crafted mounts matched to a large aperture, harnessing the power of the basic equations of the telescopes design to bring the heavens into closer, brighter examination increased humankind's understanding of space and Earth's place in the Galaxy. Among the accomplishments, Kuiper discovered that Saturn's Moon [[Titan (moon)|Titan]] has an atmosphere.<ref name="Science"/>

[[File:Yerkes Observatory Rear.jpg|thumb|left|600px|Panorma of the Observatory building, 2016]]
{{clear}}

==See also==
*[[List of largest optical refracting telescopes]]
*[[List of astronomical observatories]]
* [[List of largest optical telescopes in the 20th century]]
* [[List of largest optical telescopes in the 19th century]]
*[[Yerkes 41-inch reflector]]

==References==
{{Reflist|3}}

==External links==
{{commons category-inline}}
*[http://www.cr.nps.gov/history/online_books/butowsky5/astro4p.htm Description and history] from the [[National Park Service]].
*[http://www.saveyerkes.com/ Save Yerkes]
*[https://web.archive.org/web/20070325192503/http://yerkes.uchicago.edu/ysg/ Yerkes Study Group]
*[http://www.genevalakeconservancy.org Geneva Lake Conservancy]
*[https://www.glaseducation.org/about.html/ GLAS]
*[https://www.lib.uchicago.edu/e/scrc/findingaids/view.php?eadid=ICU.SPCL.YERKESLOGS Guide to the University of Chicago Yerkes Observatory Logbooks and Notebooks 1892-1988] at the [https://www.lib.uchicago.edu/scrc/ University of Chicago Special Collections Research Center]
*[https://www.lib.uchicago.edu/e/scrc/findingaids/view.php?eadid=ICU.SPCL.YERKESOFCDIR Guide to the University of Chicago, Yerkes Observatory, Office of the Director Records 1891-1946] at the [https://www.lib.uchicago.edu/scrc/ University of Chicago Special Collections Research Center]

{{UChicago}}

[[Category:Astronomical observatories in Wisconsin]]
[[Category:Research institutes of the University of Chicago]]
[[Category:Buildings and structures in Walworth County, Wisconsin]]

Yerkes Observatory

2020-11-19T20:32:17Z

Blastr42:

{{Infobox Observatory
| established = 1892<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1896ApJ.....3..215H|title=1896ApJ.....3..215H Page 215|website=adsabs.harvard.edu|bibcode=1896ApJ.....3..215H}}</ref>
|telescope1_name = 40-inch (102 cm)
|telescope1_type = [[Refracting telescope|refractor]] Dedicated 1897
|telescope2_name = 40-inch (102 cm)
|telescope2_type = [[Ritchey–Chrétien telescope|Ritchey–Chrétien reflector]] Since 1968
|telescope3_name = 24-inch (61 cm)
|telescope3_type = [[Cassegrain reflector]] Boller & Chivens
|telescope4_name = 10-inch (25 cm)
|telescope4_type = Cassegrain reflector
|telescope5_name = 7-inch (18 cm)
|telescope5_type = [[Schmidt camera]]
|telescope6_name =12 inch
|telescope6_type = Kenwood Refractor (''former'')
|telescope7_name =23.5 inch
|telescope7_type = The "Two Foot" (''former'')
}}
[[File:Yerkes 40 inch Refractor Telescope-1897.jpg|thumb|1897 photo of the {{convert|40|in|cm|abbr=on}} refractor at the Yerkes Observatory.]]
[[File:The Americana - a universal reference library, comprising the arts and sciences, literature, history, biograhy, geography, commerce, etc., of the world (1903) (14771315644).jpg|thumb|Telescope controls of the {{convert|40|in|cm|abbr=on}} refractor]]

'''Yerkes Observatory''' ({{IPAc-en|ˈ|j|ɜːr|k|iː|z}} {{respell|YUR|keez}}) is an [[Observatory#Astronomical observatories|astronomical observatory]] located in [[Williams Bay, Wisconsin]], U.S.A. It was operated by the [[University of Chicago]] Department of Astronomy and Astrophysics<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/|title=Yerkes Observatory-Home}}</ref><ref name="astro.uchicago.edu">{{Cite web|url=http://astro.uchicago.edu/aboutus/history.php|title=The Department of Astronomy and Astrophysics {{!}} A Bit of History|website=astro.uchicago.edu|access-date=2019-06-16}}</ref> from its founding in 1897 to 2020. Ownership was transferred to the non-profit Yerkes Future Foundation (YFF) in May, 2020.

The observatory, sometimes called "the birthplace of modern astrophysics", was founded in 1892 by astronomer [[George Ellery Hale]] and financed by businessman [[Charles Tyson Yerkes|Charles T. Yerkes]].<ref name="Frentress">{{Cite web |url=https://www.space.com/26858-yerkes-observatory.html |title=Yerkes Observatory: Home of Largest Refracting Telescope |last=Fentress |first=Steve |date=October 2019 |website=Space.com |language=en |access-date=2020-02-23}}</ref>
It represented a shift in the thinking about observatories, from their being mere housing for telescopes and observers, to the early-20th-century concept of observation equipment integrated with laboratory space for [[physics]] and [[chemistry]] analysis.

The observatory's main dome houses a 40-inch (102-cm) diameter doublet lens [[refracting telescope]], the largest refractor ever successfully used for astronomy.<ref>{{cite news
| title=Yerkes Observatory: Home of Largest Refracting Telescope
| url=http://www.space.com/26858-yerkes-observatory.html
| work=Space.com
| author=Elizabeth Howell
| date=August 15, 2014
| accessdate=December 15, 2015
}}</ref> Two smaller domes house 40-inch (102-cm) and 24-inch (61-cm) [[reflecting telescopes]]. There are several smaller telescopes - some permanently mounted - that are primarily used for educational purposes. The observatory also holds a collection of over 170,000 photographic plates.<ref>{{cite web|url=http://astro.uchicago.edu/yerkes/plates/plates.html|archive-url=https://web.archive.org/web/20110514110259/http://astro.uchicago.edu/yerkes/plates/plates.html|url-status=dead|archive-date=2011-05-14|title=Observatory website|publisher=}}</ref>

The Yerkes 40-inch was the largest [[refracting telescope|refracting-type telescope]] in the world when it was dedicated although there had been several larger [[reflecting telescope]]s. During this time, there were many questions about the merits of the various materials used to construct and design telescopes. Another large telescope of this period was the [[Great Melbourne Telescope]], which was also a reflector. In the United States, the [[James Lick telescope|Lick refractor]] had just a few years earlier come online in California with a 91-cm lens.

Prior to its installation, the telescope on its enormous German [[equatorial mount]] was shown at the [[World's Columbian Exposition|Columbian Exhibition]] in Chicago during the time the observatory was under construction.

The observatory was a center for serious astronomical research for more than 100 years. By the 21st century, however, it had reached the end of its research life. The University of Chicago closed the Observatory to the public in October 2018. In November 2019, "an agreement in principle" was announced that the University would transfer Yerkes Observatory to the non-profit Yerkes Future Foundation (YFF). The transfer of ownership took place on May 1, 2020.<ref>{{cite news
| title=Foundation celebrates donation and takes ownership of Yerkes Observatory
| url=https://www.lakegenevanews.net/news/local/foundation-celebrates-donation-and-takes-ownership-of-yerkes-observatory/article_1701caaf-8a68-5e12-89ab-d7d2ab2eb380.html
| work=lakegenevanews.net
| author=Connor Carynski
| date=May 1, 2020
| accessdate=June 9, 2010
}}</ref>

==Telescopes==

[[File:Yerkes Observatory Astro4p6.jpg|thumb|left|[[Alvan Clark]] polishes the big Yerkes objective lens in 1896]]
In the 1860s Chicago became home of the largest telescope in America, the Dearborn 18 1/2 inch refractor.<ref>[http://www.phy.olemiss.edu/Astro/WAG_99_deller.pdf]</ref> Later surpassed by the U.S. Naval Observatory's 26 inch, which would go on to discover the [[moons of Mars]] in 1877, there was an extraordinary increase of larger telescopes in finely furnished observatories in the late 1800s. In the 1890s various forces came together to establish an observatory of art, science, and superlative instruments in Williams Bay, Wisconsin.

The telescope was surpassed by the Harvard College Observatory, 60 inch reflector less than ten years later, although it remained a center for research for decades afterwards. In addition to the large refractor, Yerkes also conducted a great amount of Solar observations.

===Background===
Yerkes Observatory's 40-inch (~102 cm) [[refracting telescope]] has a doublet lens produced by the optical firm [[Alvan Clark & Sons]] and a mounting by the [[Warner & Swasey Company]]. It was the largest refracting telescope used for astronomical research.<ref>{{cite journal
|last=Starr
|first=Frederick
|date=October 1897
|title=Science at the University of Chicago
|journal=Popular Science Monthly
|publisher=D. Appleton and Company
|location=New York
|volume=51
|issue=May to October 1897
|pages=802–803
|url=https://archive.org/stream/appletonspopular51youmrich#page/802/mode/2up
|accessdate=October 25, 2015
|language=English}}</ref><ref name="galaxy196506">{{Cite magazine
|last1=Ley
|first1=Willy
|author=
|last2=Menzel
|first2=Donald H.
|last3=Richardson
|first3=Robert S.
|date=June 1965
|title=The Observatory on the Moon
|department=For Your Information
|url=https://archive.org/stream/Galaxy_v23n05_1965-06#page/n131/mode/2up
|magazine=Galaxy Science Fiction
|pages=132–150
|type=
}}</ref> In the years following its establishment, the bar was set and tried to be exceeded; an even larger demonstration refractor, the [[Great Paris Exhibition Telescope of 1900]], was exhibited at the [[Exposition Universelle (1900)|Paris Universal Exhibition of 1900]].{{r|galaxy196506}}

However, this was not much of a success and was dismantled, and it did not become part of an active University observatory. The mounting and tube for the 40-inch telescope was exhibited at the 1893 [[World's Columbian Exposition]] in Chicago before being installed in the observatory. The grinding of the lens was completed later.<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/history/1893.html|title=Yerkes Observatory - 1893 History of Yerkes Observatory}}</ref>[[File:Yerkes dome construction.jpg|thumb|Three workers on the skeleton of Yerkes Observatory's great dome viewed from the roof. c.1896]]

===The 40-inch aperture refractor===
[[File:Chicago's Great Telescope (3573567148).jpg|thumb|left|The Yerkes Great refractor mounted at the 1893 World's Fair in Chicago]]

The glass blanks for what would become Yerkes Great Refractor were made in Paris, France by Mantois and delivered to [[Alvan Clark & Sons]] in Massachusetts where they were completed.<ref name=":2">{{Cite book|url=https://books.google.com/books?id=qrRz-sXyXJYC&q=yerkes+refractor+at+exhibition&pg=PA51|title=The General History of Astronomy|date=1900|publisher=Cambridge University Press|isbn=9780521242561|language=en}}</ref> Clark then made what would be the largest telescope lens ever crafted and this was mounted to an Equatorial mount made by Warner & Swasey for the observatory.<ref name=":2" /> The telescope had an aperture of 40 inches (~102 cm) and focal length of 19.3 meters, making it an f/19.<ref name=":2" />

The lens, an achromatic doublet which has two sections to reduce chromatic aberration, weighed 225 kilograms, and was the last big lens made by Clark before he died in 1897.<ref name=":2" /> Glass lens telescopes had a good reputation compared to speculum metal and silver on glass mirror telescopes, which had not quite proven themselves in the 1890s. For example, the [[Leviathan of Parsonstown]] was a 1.8 meter telescope with a speculum metal mirror, but getting good astronomical results from this technology could be difficult, and another large telescope of this period was the [[Great Melbourne Telescope]] in Australia, also a metal mirror telescope.

[[File:PSM V65 D017 Rumford spectroheliograph attached to the yerkes telescope.png|thumb|Spectroheliograph instrument on the 40-inch refractor in 1904]]
Some of the instruments for the 40-inch refractor (circa 1890s):<ref name=":4">{{Cite journal|url=http://adsabs.harvard.edu/full/1896ApJ.....3..215H|title=1896ApJ.....3..215H Page 215|website=adsabs.harvard.edu|bibcode=1896ApJ.....3..215H|access-date=2019-10-21}}</ref>
*[[Position micrometer|Filar Micrometer]]
*Solar spectrograph
*[[Spectroheliograph]]
*Stellar spectrograph
*Photoheliograph

The 40-inch refractor was modernized in the late 1960s with electronics of the period.<ref name=":9">{{Cite journal|url=http://adsabs.harvard.edu/full/1967AJ.....72.1158O|title=1967AJ.....72.1158O Page 1158|website=adsabs.harvard.edu|bibcode=1967AJ.....72.1158O|access-date=2019-10-22}}</ref> The telescope was painted, the manual controls were removed, and electric operations were added at this time.<ref name=":9" /> This included [[nixie tube]] displays for its operation.<ref name=":9" />

===The 41-inch reflector===
{{main|Yerkes 41-inch reflector}}
In the late 1960s a 40-inch reflecting telescope was added. <ref name=":6">{{Cite web|url=https://www.skyandtelescope.com/astronomy-news/yerkes-on-the-block/|title=Yerkes On the Block|last=Roth|first=Joshua|date=2004-12-15|website=Sky & Telescope|language=en-US|access-date=2019-10-21}}</ref><ref>{{Cite web|url=http://chronicle.uchicago.edu/020815/yerkes.shtml|title=Constructive point of view|website=chronicle.uchicago.edu|access-date=2020-03-03}}</ref> The 41 inch was finished by 1968, with overall installation completed by December 1967 and the optics in 1968.<ref name="Darling">{{Cite web|url=http://www.daviddarling.info/encyclopedia/Y/Yerkes.html|title=Yerkes Observatory|last=Darling|first=David|website=www.daviddarling.info|access-date=2019-10-24}}</ref><ref name="1969BAAS....1..135O Page 135">{{Cite journal|url=http://adsabs.harvard.edu/full/1969BAAS....1..135O|title=1969BAAS....1..135O Page 135|website=adsabs.harvard.edu|bibcode=1969BAAS....1..135O|access-date=2019-10-24}}</ref> While the telescope has a clear aperture of 40-inches, the mirror's physical diameter measures 41-inches leading to the telescope usually being called the "41 inch" to avoid confusion with the 40 inch refractor.<ref name="1969BAAS....1..135O Page 135"/> <ref name="Darling"/><ref name=":7">{{Cite journal|url=http://adsabs.harvard.edu/full/1969BAAS....1..135O|title=1969BAAS....1..135O Page 135|website=adsabs.harvard.edu|bibcode=1969BAAS....1..135O|access-date=2019-10-22}}</ref>
The mirror is made from low-expansion glass.<ref name="adsabs.harvard.edu">{{Cite journal|url=http://adsabs.harvard.edu/full/1967AJ.....72.1158O|title=1967AJ.....72.1158O Page 1158|website=adsabs.harvard.edu|bibcode=1967AJ.....72.1158O|access-date=2020-03-03}}</ref> The glass used was CER-VII-R.<ref name="adsabs.harvard.edu"/>

The launch instruments for the 41 inch reflector included:<ref name=":7" />

* Image tube spectrograph
* photoelectric photometer
* photoelectric spectrophotometer

The 40-inch reflector is of the [[Ritchey–Chrétien telescope|''Ritchey''-''Chretien'']] optical design.<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1969PASP...81..254K|title=1969PASP...81..254K Page 254|website=adsabs.harvard.edu|bibcode=1969PASP...81..254K|access-date=2019-10-24}}</ref> The 41-inch helped pioneer the field of adaptive optics.<ref>{{cite journal|title=Field tests of the Wavefront Control Experiment|journal=Adaptive Optics in Astronomy|date=31 May 1994|doi=10.1117/12.176024|s2cid=119806080|url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/2201/1/Field-tests-of-the-Wavefront-Control-Experiment/10.1117/12.176024.short}}</ref>

===Additional instruments and equipment===
[[File:RitcheyTelescope.jpg|thumb|The old Yerkes 24 inch (2 foot telescope) reflecting telescope, now in a museum]]
[[File:EB1911 Telescope - Fig. 19. Bruce Telescope, Yerkes Observatory.png|thumb|Diagram of the Bruce astrograph]]
A 12 inch refractor was moved to Yerkes from [[Kenwood Astrophysical Observatory|Kenwood Observatory]] in the 1890s.<ref name=":4"/>
Two other telescopes planned for the observatory in the 1890s were a 12-inch aperture refractor and a 24-inch reflecting telescope.<ref name=":4" /> There was a [[heliostat]] mirror and a meridian room for a [[transit instrument]].<ref name=":4" />

A two-foot aperture reflecting telescope was manufactured at the observatory itself.<ref name=":10">{{Cite journal|url=http://adsabs.harvard.edu/full/1901ApJ....14..217R|title=1901ApJ....14..217R Page 217|website=adsabs.harvard.edu|bibcode=1901ApJ....14..217R|access-date=2019-10-22}}</ref> The clear aperture of the telescope was actually 23.5 inches.<ref name=":10" /> The [[glass blank]]s were cast in France by Saint Gobain Glass Works, and then were figured (polished into telescopic shape) at the Yerkes Observatory.<ref name=":10" /> The 'Two foot telescope' used a roughly seven foot long skeleton truss made of aluminum.<ref>{{Cite web|url=http://articles.adsabs.harvard.edu/full/gif/1901ApJ....14..217R/0000225.000.html|title=1901ApJ....14..217R Page 225|website=articles.adsabs.harvard.edu|access-date=2019-10-22}}</ref>

At one point the Observatory had an [[IBM 1620]] computer, which it used for three years.<ref name=":5">{{Cite journal|url=http://adsabs.harvard.edu/full/1967AJ.....72.1158O|title=1967AJ.....72.1158O Page 1158|website=adsabs.harvard.edu|bibcode=1967AJ.....72.1158O|access-date=2019-10-21}}</ref> This was replaced with an [[IBM 1130]] computer in the 1960s.<ref name=":5" />

A Microphotometer was built by Gaertner Scientific Corporation, which was delivered in February 1968 to the observatory.<ref>{{Cite web|url=http://www.daviddarling.info/encyclopedia/Y/Yerkes.html|title=Yerkes Observatory|last=Darling|first=David|website=www.daviddarling.info|access-date=2020-03-03}}</ref><ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1969BAAS....1..135O|title=1969BAAS....1..135O Page 135|website=adsabs.harvard.edu|bibcode=1969BAAS....1..135O|access-date=2020-03-03}}</ref>

Later, there was another 24 inch reflecting telescope by [[Boller and Chivens|Boller & Chivens.]]<ref name=":6" /><ref>{{Cite web|url=http://www.daviddarling.info/encyclopedia/Y/Yerkes.html|title=Yerkes Observatory|last=Darling|first=David|website=www.daviddarling.info|access-date=2019-10-22}}</ref> This was contracted in the early 1960s under direction of observatory director [[W. Albert Hiltner]].<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1963AJ.....68..756M|title=1963AJ.....68..756M Page 756|website=adsabs.harvard.edu|bibcode=1963AJ.....68..756M|access-date=2019-10-22}}</ref> This telescope was installed in one of the smaller Yerkes domes, and it is known to have been used for visitor programs.<ref>{{Cite web|url=https://bollerandchivens.com/?p=1848|title=24 Inch (.61 Meters) Telescope for University of Chicago, Yerkes Observatory - Boller and Chivens: A History "Where Precision is a Way of Life" - Boller and Chivens were makers of Telescopes and Precision Instruments|website=bollerandchivens.com|access-date=2019-10-24}}</ref> This was a design by Boller & Chivens with Cassegrain optical setup, with a 24 inch (61 cm) clear aperture and is on an off-axis equatorial mount.<ref>{{Cite web|url=http://bollerandchivens.com/?p=2492|title=24-Inch (.61 meter) Telescope Specifications - Boller and Chivens: A History "Where Precision is a Way of Life" - Boller and Chivens were makers of Telescopes and Precision Instruments|website=bollerandchivens.com|access-date=2019-10-24}}</ref>

A 7-inch (18 cm) diameter aperture [[Schmidt camera]] was also at Yerkes Observatory.<ref>{{Cite web|url=http://photoarchive.lib.uchicago.edu/db.xqy?one=apf2-08781.xml|title=Yerkes Observatory : Photographic Archive : The University of Chicago|website=photoarchive.lib.uchicago.edu|access-date=2019-10-24}}</ref>

The Snow Solar Telescope was first established at Yerkes Observatory, and then later moved in 1904 out to California.<ref name=":13" /> A major difficulty of these telescopes was dealing with heat from the Sun, and it was built horizontally, but lead to a vertical solar tower design afterwards.<ref name=":13" /> Solar tower telescopes would be a popular style for solar observatories in the 20th century, and are still used in the 21st century to observe the Sun.

Another instrument was the Bruce photographic telescope.<ref name=":15">{{Cite journal|url=http://adsabs.harvard.edu/full/1905ApJ....21...35B|title=1905ApJ....21...35B Page 35|website=adsabs.harvard.edu|bibcode=1905ApJ....21...35B|access-date=2019-11-02}}</ref> The telescope had two objective lens for photography, one doublet of 10 inches aperture and another of 6.5 inches; in addition there is a 5-inch guide scope for visual viewing.<ref name=":15" /> The telescope was constructed from funds donated in 1897.<ref name=":15" /> The telescope was mounted on custom designed equatorial, the result of collaboration between Yerkes and Warner & Swasey, especially designed to offer an uninterrupted tracking for long image exposures.<ref name=":15" /> The images were taken on glass plates about a foot on each side.<ref name="auto2">{{Cite web|url=http://www.artdeciel.com/astrophotography-camera-detail.aspx?Camera_ID=254|title=Famos Astrograph/Camera Detail|website=www.artdeciel.com|access-date=2019-11-02}}</ref>

The Bruce astrograph lenses were made by Brashear with Mantois of Paris glass blanks, and the lenses were completed by the year 1900.<ref name=":15" /> The overall telescope was not completed until 1904, where it was installed in its own dome at Yerkes.<ref name="auto2"/>

The astronomer [[Edward Emerson Barnard]]'s work with the Bruce telescope lead to the publication of a sky atlas using images taken with the instrument, and also a catalog of [[dark nebula]] known as the [[Barnard Catalogue|Barnard catalog]].<ref>{{Cite book|url=https://books.google.com/books?id=wyWjVWYWoO8C&q=bruce+astrograph+yerkes&pg=PA396|title=Observing and Cataloguing Nebulae and Star Clusters: From Herschel to Dreyer's New General Catalogue|last=Steinicke|first=Wolfgang|date=2010-08-19|publisher=Cambridge University Press|isbn=9781139490108|language=en}}</ref>

== Dedication ==
[[File:Yerkes Observatory Astro4p3.jpg|thumb|left|Group photo from the dedication in October 1897]]
The Observatory was dedicated on October 21, 1897 and there was a large party with University, astronomers, and scientists.<ref name="chronicle.uchicago.edu">{{Cite web|url=http://chronicle.uchicago.edu/970320/yerkes.shtml|title=Yerkes Observatory: A century of stellar science|website=chronicle.uchicago.edu|access-date=2019-10-21}}</ref>

Before the dedication a conference of astronomers and astrophysicists was hosted at Yerkes Observatory, and took place on October 18–20, 1897.<ref>{{Cite web|url=https://had.aas.org/resources/aashistory/early-meetings/1897-1906|title=Meetings of the AAS: 1897-1906 {{!}} Historical Astronomy Division|website=had.aas.org|access-date=2019-10-22}}</ref> This is noted as a precursor to the founding of the [[American Astronomical Society]]

Although dedicated in 1897, it was founded in 1892.<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1896ApJ.....3..215H|title=1896ApJ.....3..215H Page 215|website=adsabs.harvard.edu|bibcode=1896ApJ.....3..215H|access-date=2020-03-03}}</ref> Also, astronomical observations had started in the summer of 1897 before the dedication.<ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1947PA.....55..413S|title=1947PA.....55..413S Page 413|website=adsabs.harvard.edu|bibcode=1947PA.....55..413S|access-date=2019-10-30}}</ref>

==Research & Observations==
[[File:Yerkes Messier 51 Canum Venaticorum 1902.jpg|thumb|A photo of the [[Whirlpool Galaxy|Messier 51 galaxy]] taken on June 3, 1902 at the Yerkes Observatory]]
[[File:Annual report of the Board of Regents of the Smithsonian Institution (1901) (17813060474).jpg|thumb|George Ritchey image of what he called the ''Great Neubla in Cygnus'' (In modern times the [[Veil Nebula]]); taken with the two-foot reflecting telescope with 3 hours exposure]]
Research conducted at Yerkes in the last decade{{when|date=August 2018}} includes work on the [[interstellar medium]], [[globular cluster]] formation, [[infrared]] astronomy, and [[near-Earth objects]]. Until recently the [[University of Chicago]] also maintained an engineering center in the observatory, dedicated to building and maintaining scientific instruments. In 2012 the engineers completed work on the High-resolution Airborne Wideband Camera (HAWC), part of the [[Stratospheric Observatory for Infrared Astronomy]] (SOFIA).<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/hawc.html|title=Yerkes Observatory-R & D-HAWC}}</ref>
Researchers also use the Yerkes collection of over 170,000 archival photographic plates that date back to the 1890s.<ref>{{Cite web|url=http://astro.uchicago.edu/yerkes/plates/plates.html|title=The Yerkes Observatory Photographic Plates}}</ref> The past few years have seen astronomical research largely replaced by educational outreach and astronomical tourism activities.

In June 1967, Yerkes Observatory hosted the to-date largest meeting of the American Astronomical Society, with talks on over 200 papers.<ref name=":5" />

The ''Yerkes spectral classification'' (aka ''MKK'' system) was a system of stellar spectral classification introduced in 1943 by [[William Wilson Morgan]], [[Philip Childs Keenan|Philip C. Keenan]], and [[Edith Kellman]] from Yerkes Observatory.<ref>{{cite book|title=An atlas of stellar spectra, with an outline of spectral classification|last1=Morgan|first1=William Wilson|last2=Keenan|first2=Philip Childs|last3=Kellman|first3=Edith|date=1943|publisher=The University of Chicago Press|bibcode=1943assw.book.....M|oclc=1806249}}</ref> This two-dimensional ([[temperature]] and [[luminosity]]) classification scheme is based on [[spectral line]]s sensitive to stellar temperature and [[surface gravity]], which are related to luminosity (the ''Harvard classification'' is based on surface temperature). Later, in 1953, after some revisions of lists of standard stars and classification criteria, the scheme was named the ''Morgan–Keenan classification'', or ''MK.''<ref name="ref_MK">{{cite journal|last1=Morgan|first1=William Wilson|last2=Keenan|first2=Philip Childs|date=1973|title=Spectral Classification|journal=Annual Review of Astronomy and Astrophysics|volume=11|pages=29–50|bibcode=1973ARA&A..11...29M|doi=10.1146/annurev.aa.11.090173.000333}}</ref>

Research work of the Yerkes Observatory has been cited over 10,000 times.<ref>{{Cite web|url=https://legacy.aas.org/files/aas-donahue-yerkes-letter.pdf|title=aas-donahue-yerkes-letter|last=|first=|date=July 10, 2018|website=AMERICAN ASTRONOMICAL SOCIETY|access-date=2020-03-03}}</ref>

In 1899, observations of Neptune's moon Triton were published, with data recorded using the Warner & Swasey micrometer.<ref name=":14">{{Cite book|url=https://books.google.com/books?id=0pURAAAAYAAJ&q=asteroids+discovered+with+40+inch+yerke&pg=PA197|title=The Astronomical Journal|date=1900|publisher=American Institute of Physics.|language=en}}</ref> In 1898 and 1899, Neptune was at opposition.<ref name=":14" />

In 1906, a star catalog of over 13,600 stars was published.<ref name=":12">{{Cite web|url=https://www.space.com/26858-yerkes-observatory.html|title=Yerkes Observatory: Home of Largest Refracting Telescope|last1=Science|first1=Elizabeth Howell 2014-08-16T02:26:07Z|last2=Astronomy|website=Space.com|language=en|access-date=2019-10-24}}</ref> Also, there was some important work on Solar research in the early years, which was of interest to Hale.<ref name=":12" /> He went on to the Snow Solar Telescope at Mount Wilson in California.<ref name=":13">{{Cite web|url=https://www.mtwilson.edu/vt-snow-solar-telescope/|title=VT Snow Solar Telescope|date=2017-01-29|website=Mount Wilson Observatory|language=en-US|access-date=2019-10-24}}</ref> This was first operated at Yerkes and then moved to California.<ref name=":13" />

An example of an asteroid discovered at Yerkes is [[1024 Hale]], provisional designation {{mp|A923 YO|13}}, a carbonaceous background [[asteroid]] from the outer regions of the [[asteroid belt]], approximately {{convert|45|km|mi|abbr=off|sp=us}} in diameter. The asteroid was discovered on 2 December 1923 by Belgian–American astronomer [[George Van Biesbroeck]] at Yerkes Observatory, and it was named for astronomer George Ellery Hale of Yerkes Observatory fame. Some additional examples include [[990 Yerkes]], [[991 McDonalda]], and [[992 Swasey]] around this time; many more minor planets would be discovered at the observatory in the following decades.

==Notable staff and visitors==
[[File:Yerkes Observatory Astro4p7.jpg|thumb|350px|The 40-inch (1.02 m) Refractor backdrops Einstein's visit to the Observatory in May 1921]]

Notable astronomers who conducted research at Yerkes include [[Albert Michelson]],<ref>{{cite journal |last=Gale |first=Henry G. |authorlink=Henry Gale (astrophysicist) |date=July 1931 |title=Albert A. Michelson |url= |journal=The Astrophysical Journal |volume=74 |issue=1 |pages=1–9 |doi=10.1086/143320 |accessdate= }}</ref> [[Edwin Hubble]] (who did his graduate work at Yerkes and for whom the [[Hubble Space Telescope]] was named), [[Subrahmanyan Chandrasekhar]] (for whom the [[Chandra X-ray Observatory|Chandra Space Telescope]] was named), Russian-American astronomer [[Otto Struve]],<ref name="astro.uchicago.edu"/> Dutch-American astronomer [[Gerard Kuiper]] (noted for theorizing the [[Kuiper belt]], home to dwarf planet Pluto),
[[Nancy Grace Roman]], NASA's first Chief of Astronomy (who did her graduate work at Yerkes), and the twentieth-century popularizer of astronomy [[Carl Sagan]].

In May 1921, [[Albert Einstein]] visited the Yerkes Observatory.<ref>{{Cite web|url=https://atthelakemagazine.com/einstein-yerkes-observatory/|title=The Day Einstein Came to Town|date=2013-12-20|website=At The Lake Magazine|language=en-US|access-date=2019-10-21}}</ref>

Directors of Yerkes Observatory:<ref>{{Cite web|url=https://astro.uchicago.edu/aboutus/history.php|title=The Department of Astronomy and Astrophysics {{!}} A Bit of History|website=astro.uchicago.edu|access-date=2020-03-03}}</ref>
*2012 - 2018 Doyal ''Al'' Harper (2nd time)
*2001 - 2012 Kyle M. Cudworth
*1989 - 2001 Richard G. Kron
*1982 - 1989 Doyal ''Al'' Harper
*1974 - 1982 Lewis M. Hobbs
*1972 - 1974 William Van Altena
*1966 - 1972 C. Robert O'Dell
*1963 - 1966 [[William Hiltner]]
*1960 - 1963 [[William W. Morgan]]
*1957 - 1960 [[Gerard P. Kuiper]] (2nd time)
*1950 - 1957 [[Bengt Stromgren]]
*1947 - 1950 Gerard P. Kuiper
*1932 - 1947 [[Otto Struve]]
*1903 - 1932 [[Edwin B. Frost]]
*1897 - 1903 [[George Ellery Hale]]

==The 2005 proposed development and preservation initiative==
[[File:Grandest century in the world's history; containing a full and graphic account of the marvelous achievements of one hundred years, including great battles and conquests; the rise and fall of nations; (14781534012).jpg|thumb|A year 1900 book makes note of the Observatory]]
In March 2005, the University of Chicago announced plans to sell the observatory and its land on the shore of [[Geneva Lake]]. Two purchasers had expressed an interest: Mirbeau, an East Coast developer that wanted to build luxury homes, and [[Aurora University]], which has a campus straddling the Williams Bay property. The Geneva Lake Conservancy, a regional conservation and [[land trust]] organization, maintained that it was critical to save the historic Yerkes Observatory structures and telescopes for education and research, as well as to conserve the rare undeveloped, wooded lakefront and deep [[forest]] sections of the {{convert|77|acre|m2|adj=on|abbr=out|sp=us}} site. On June 7, 2006, the University announced it would sell the facility to Mirbeau for US$8 million with stipulations to preserve the observatory, the surrounding {{convert|30|acre|m2|abbr=on}}, and the entire shoreline of the site.<ref>{{Cite web|url=http://www-news.uchicago.edu/releases/06/060607.yerkes.shtml|title=Agreement provides for preservation of historic Yerkes Observatory|website=www-news.uchicago.edu|access-date=2019-06-16}}</ref>

Under the Mirbeau plan, a 100-room resort with a large [[spa]] operation and attendant parking and support facilities was to be located on the {{convert|9|acre|m2|adj=on|abbr=out|sp=us}} virgin wooded Yerkes land on the lakeshore—the last such undeveloped, natural site on Geneva Lake's {{convert|21|mi|km|abbr=off|adj=on|sp=us}} shoreline. About 70 homes were to be developed on the upper Yerkes property surrounding the historic observatory. These grounds had been designed more than 100 years previously by [[John Charles Olmsted]], the nephew and adopted son of famed [[landscape architect]] [[Frederick Law Olmsted]]. Ultimately, Williams Bay's refusal to change the zoning from education to residential caused Mirbeau to abandon its development plans.

In view of the public controversy surrounding the development proposals, the university suspended these plans in January 2007.<ref>{{cite web|url=http://www.chicagotribune.com/business/chi-0701040304jan04,0,3146579.story?coll=chi-business-hed|title=Topic Galleries - chicagotribune.com|publisher=}}</ref> The university's department of astronomy and astrophysics then formed a study group, including representatives from the faculty and observatory and a wide range of other involved parties, to plan for the operation of a regional center for science education at the observatory.<ref>{{Cite web|url=http://www-news.uchicago.edu/releases/07/070228.yerkes.shtml|title=Yerkes Study Group formed to consider observatory's future|website=www-news.uchicago.edu|access-date=2019-06-16}}</ref> The study group began its work in February 2007 and issued its final report November 30, 2007.<ref name="report">{{cite web|url=http://astro.uchicago.edu/yerkes/ysg/YSG_Final_Report.pdf|title=Final Report of the Yerkes Study Group, November 30, 2007, Yerkes Science Center: Options for Management and Funding|publisher=}}</ref>
The report recommended creating a formal business plan to ensure the financial viability of the proposed science education center, establishing ownership of the proposed center before initiating plans for creating it, and forming a partnership between the University of Chicago and local interests to plan for the center. It also suggested that some lakefront and woods parcels could be sold for residential development.<ref name="report"/>

==Closure==
[[File:Yerkes Observatory 2009 Oct.jpg|thumb|Yerkes in 2009]]
In March 2018, the University of Chicago announced that it would no longer operate the observatory after October 1, 2018, and would be seeking a new owner.<ref>Scott Williams. "[http://www.lakegenevanews.net/news/yerkes-observatory-closing-after-years-on-lakefront/article_cc29cbf9-12a7-5fd6-abc1-357ce8f3bd6f.html Yerkes Observatory closing after 100 years on lakefront]".{{subscription required}} ''Lake Geneva Regional News'', March 7, 2018.</ref> In May 2018, the Yerkes Future Foundation, a group of local residents, submitted an expression of interest to the University of Chicago with a proposal that would seek to maintain public access to the site and continuation of the educational programs.<ref>{{Cite web|url=https://www.chicagomaroon.com/article/2018/5/11/new-group-submits-proposal-keep-yerkes-open/|title=New Group Submits Proposal to Keep Yerkes Open|website=www.chicagomaroon.com|language=en|access-date=2018-09-30}}</ref> Transfer of operation to a successor operator was not arranged by the end of August, and the facility was closed to the general public on October 1. Some research activities continued at the Observatory, including access and use of the extensive historical glass plate archives at the site. Yerkes education and outreach staff formed a nonprofit organization – GLAS – to continue their programs at another site after the closing.<ref>{{Cite web|url=https://www.glaseducation.org/|title=GLAS EDUCATION|website=GLAS EDUCATION|language=en|access-date=2018-09-30}}</ref>

In May 2019, the University continued to negotiate with interested parties on Yerkes' future, primarily with the Yerkes Future Foundation. It was announced in November 2018 that a sticking point has been the need to include the Yerkes family in the discussions. Mr. Yerkes' agreement in making his donation to the University transfers ownership “To have and to hold unto the said Trustees [of the University of Chicago] and their successors so long as they shall use the same for the purpose of astronomical investigation, but upon their failure to do so, the property hereby conveyed shall revert to the said Charles T. Yerkes or his heirs at law, the same as if this conveyance had never been made.” <ref>{{Cite web|url=https://www.chicagomaroon.com/article/2019/5/8/original-bequest-letter-for-yerkes-observatory-hold/|title=Original bequest letter for Yerkes Observatory holds up its future|website=The Chicago Maroon|language=en|access-date=2019-05-28}}</ref>

For the closing, there is a new gate with a sign that reads "Facilities Closed To The Public" since October 1, 2018.<ref>{{Cite web|url=https://www.lakegenevanews.net/news/yerkes-like-a-cemetery-one-year-after-shutdown/article_f1a6e0c0-d167-5edc-a761-5362f72e4639.html|title=Yerkes like a 'cemetery' one year after shutdown|last=swilliams@lakegenevanews.net|first=Scott Williams|website=Lake Geneva News|language=en|access-date=2019-10-21}}</ref>

== Gargoyle sculptures, location, and landscaping ==
[[File:Yerkesgargoyle.jpg|thumb|upright|A Yerkes Gargoyle sculpture on the Observatory building]]
The Observatory grounds and buildings are renowned for more than the Great Refractor, but also sculptures and architecture.<ref name=":3">{{Cite web|url=https://www.skyandtelescope.com/astronomy-news/not-quite-closing-yerkes-observatory/|title=The Not-Quite Closing of Yerkes Observatory|date=2018-03-16|website=Sky & Telescope|language=en-US|access-date=2019-10-03}}</ref> In addition, the landscaping is also famed for its design work by Olmstead.<ref name=":0" /> The observatory building was designed by architect Henry Ives Cobb, and has been referred to as being in the [[Beaux-Arts architecture|Beux Arts]] style.<ref name=":8">{{Cite web|url=https://www.wisconsinhistory.org/Records/Property/HI81162|title=OBSERVATORY DR {{!}} Property Record|date=2012-01-01|website=Wisconsin Historical Society|access-date=2019-10-22}}</ref> The building is noted for its blend of styles and rich ornamentation featuring a variety of animal and mythological designs.<ref name=":8" />

On the building there are various carvings including Lion gargoyle designs.<ref>{{Cite web|url=https://hdl.huntington.org/digital/collection/p15150coll2/id/38/|title=CONTENTdm|website=hdl.huntington.org|access-date=2019-10-03}}</ref><ref name=":3" /> There are also sculptures to represent various people that oversaw or supported construction of the telescope and the facility.<ref name="Cruikshank">{{Cite book|url=https://books.google.com/books?id=BJtIDwAAQBAJ&q=yerkes+gargoyles&pg=PA170|title=Discovering Pluto: Exploration at the Edge of the Solar System|last1=Cruikshank|first1=Dale P.|last2=Sheehan|first2=William|date=2018-02-27|publisher=University of Arizona Press|isbn=9780816534319|language=en}}</ref> The location is noted for a good and pleasant location by Lake Geneva.<ref name="Cruikshank"/> Although it does not have a high-altitude as preferred by modern observatories, it does have a lot of good weather, and was a considerable distance from the light and pollution of the City of Chicago.<ref>{{Cite journal|last=Aut|first=Kron Richard author|date=2018-07-06|title=The scientific legacy of Yerkes Observatory|journal=Physics Today|url=https://physicstoday.scitation.org/do/10.1063/PT.6.4.20180706a/abs/|language=EN|doi=10.1063/PT.6.4.20180706a}}</ref>

In 1888, Williams Bay had railway terminal added by [[Chicago & North Western Railroad]]; this provided access from the City of Chicago, and is one factor that increased the site's development in the following decades.<ref>{{Cite web|url=https://www.lakegenevanews.net/news/williams-bay-centennial-a-century-in-story-and-pictures/article_0bb078e8-7a4a-5d8d-a96d-cd1e30a1d300.html|title=Williams Bay Centennial: A century in story and pictures|last=cschultz@lakegenevanews.net|first=Chris Schultz|website=Lake Geneva News|language=en|access-date=2019-10-21}}</ref>

The editorial offices for [[The Astrophysical Journal]] were located at Yerkes Observatory until the 1960s.<ref name="chronicle.uchicago.edu"/>

The landscape was designed by the same firm that did [[New York Central Park|New York Central park]], the firm of Frederick Law Olmsted, and the grounds were noted at one point for having multiple state record trees.<ref name=":11">{{Cite web|url=https://dnr.wi.gov/topic/ForestManagement/EveryRootAnAnchor/documents/091-YerkesObservatory.pdf|title=The Trees at Yerkes Observatory|last=|first=|date=|website=|access-date=}}</ref> The tree plan design was developed in the 1910s under design from the Olmstead firm and with support of the observatory Director; the grounds included the following types of trees at that time: [[white fir]], [[Cladrastis kentukea|yellowwood tree]], [[Golden-rain tree|golden rain tree]], [[European beech]], fernleaf beech, Japanese [[pagoda tree]], [[littleleaf linden]], [[Kentucky coffeetree]], [[Gingko tree|ginkgo]], cut-leaf beeches, and [[chestnut tree]]s.<ref name=":11" />

The original landscape plan was not completed by the 1897 dedication, and there was grading and construction of gravel roads under direction of the Olmstead design as late as 1908.<ref>{{Cite web|url=https://www.lib.uchicago.edu/about/news/yerkes-observatory-photographs-now-online/|title=Yerkes Observatory Photographs Now Online - The University of Chicago Library News - The University of Chicago Library|website=www.lib.uchicago.edu|access-date=2019-10-22}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=nwniAAAAMAAJ&q=Olmstead++yerkes+observatory&pg=PA29|title=University Record|last=Chicago|first=University of|date=1908|publisher=University of Chicago Press|language=en}}</ref>

==Contemporaries on debut of the Great Yerkes Refractor==
<noinclude>
<blockquote class="toccolours" style="text-align:justify; width:40%; float:right; padding: 10px 15px 10px 15px; display:table;">
<center>'''Legend'''</center>
* {{legend2|#F0FFFF|[[Reflector telescope|Reflector (Metal mirror) or unknown]]|border=1px solid #AAAAAA}}
* {{legend2|#CCFFFF|[[Reflector telescope|Glass Reflector (Silver on glass mirror)]]|border=1px solid #AAAAAA}}
* {{legend2| |[[Refractor|Refractor (Lens)]]|border=1px solid #AAAAAA}}
</blockquote>
</noinclude>

A major contemporary for the Yerkes was the well regarded 36-inch Lick refractor in California.<ref name=":16">{{Cite web|url=https://www.nps.gov/parkhistory/online_books/butowsky5/astro4p.htm|title=National Park Service: Astronomy and Astrophysics (Yerkes Observatory)|website=www.nps.gov|access-date=2019-11-03}}</ref> The Yerkes, although just 4 inches in aperture larger, meant an increase of 23% in light-gathering ability.<ref name=":16" /> Both telescopes had achromatic doublets by [[Alvan Clark]].

Over the 19th century saw a transition in large telescope construction from refractor type to reflector type, with metal-film-coated glass mirrors tending to be used instead of difficult, older-style metal mirrors. The Yerkes was perhaps the greatest of the [[great refractor]]s, the largest astronomical instrument in the traditional style of the 19th century refractor-based observatories.

The Yerkes was not only the largest refractor, but was tied for being the largest telescope in the world with Paris Observatory reflector (48 inch, 122 cm) when it became operational in 1896.<ref name=page250>{{Cite web|url=http://articles.adsabs.harvard.edu/full/gif/1914Obs....37..245H/0000250.000.html|title=1914Obs....37..245H Page 250|accessdate=September 8, 2019}}</ref>

{| class="wikitable sortable" style="font-size:95%;"
! Name/Observatory
! class="unsortable" |[[Aperture]] cm (in)
! [[Telescope|Type]]
! Location
! Extant or Active
|- style="background:#F0FFFF"
|[[Leviathan of Parsonstown]] || 183 cm (72″) || [[Speculum metal|reflector – metal]] || [[Birr Castle]]; [[Ireland]] || 1845–1908*
|- style="background:#F0FFFF"
| [[Great Melbourne Telescope]]<ref name="stjarnhimlen.se">{{Cite web|url=http://stjarnhimlen.se/bigtel/LargestTelescope.html|title=Largest optical telescopes of the world|website=stjarnhimlen.se|accessdate=September 8, 2019}}</ref> || 122 cm (48″) || [[Speculum metal|reflector – metal]] || [[Melbourne Observatory]], Australia || 1878
|-style="background:#CCFFFF"
| National Observatory, Paris || 120 cm (47″) || [[Silver on glass|reflector – glass]] || Paris, France || 1875–1943<ref name=page250/>
|- style="background:#DAF7A6"
| Yerkes Observatory<ref name="ReferenceA">http://astro.uchicago.edu/vtour/40inch/</ref> || 102 cm (40″) || achromat || [[Williams Bay, Wisconsin]], [[United States|USA]] || 1897
|-style="background:#CCFFFF"
| Meudon Observatory 1m<ref name="auto1">{{Cite book|url=https://books.google.com/books?id=tEMiAQAAIAAJ&q=meudon+100+cm+reflector&pg=PA584|title=Popular Astronomy|date=1911|publisher=Goodsell Observatory of Carleton College|language=en}}</ref>|| 100 cm (39.4″) || reflector-glass || Meudon Observatory/ Paris Observatory || 1891 <ref name="auto3">{{Cite web|url=https://www.obspm.fr/le-telescope-de-1-metre.html?lang=en|title=Le télescope de 1 mètre - Observatoire de Paris - PSL Centre de recherche en astronomie et astrophysique|website=www.obspm.fr|access-date=2020-03-03}}</ref>
|-
|[[James Lick telescope]], [[Lick Observatory]] || 91 cm (36″) || achromat || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1888
|- style="background:#CCFFFF"
| [[Crossley telescope|Crossley Reflector]]<ref name="ucolick.org">{{Cite web|url=http://www.ucolick.org/public/telescopes/crossley.html|title=Mt. Hamilton Telescopes: CrossleyTelescope|website=www.ucolick.org|accessdate=September 8, 2019}}</ref> (Lick Observatory) || 91.4 cm (36″) || [[Silver on glass|reflector – glass]] || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1896
|}
<nowiki>*</nowiki>Note the Leviathan of Parsonstown was not used after 1890

{|
|[[File:Lick-Refraktor 3130169128.jpg|thumb|The Lick telescope in California was 91 cm aperture and debuted in 1888]]
|[[File:Grande Lunette de l'Observatoire de Meudon.jpg|thumb|The ''Grande Lunette'' of Meudon Observatory (France), was double refractor with both a 83 cm and 62 cm on one shaft and came online in 1891]]
|[[File:Berlin Treptow Archenhold Sternwarte.jpg|thumb|Germany's ''Himmelskanone'' did away with a dome (The telescope tube extends above the observatory in this image) but was quite long, also debuting 1896 like Yerkes]]
|}
{{clear}}

Understanding atmosphere and trends of telescope building of the late 19th century puts the choice of a large refactor in perspective. Although there were some very large reflectors, the [[Speculum metal|speculum mirrors]] they relied on reflected about 2/3 of the light and had high upkeep. A major breakthrough came in the middle of the 19th century with a technique for coating glass with a metal film. This process ([[Silvering|silver on glass]]) eventually lead to some bigger glass reflectors. Silvering has its own issues, in that coating must be reapplied usually every 2 years or so depending on conditions, and also it must be done very thinly so as to not effect the optical properties of the mirror.

A large glass reflector (122 cm diameter glass mirror) was established in Paris by 1876, but problems with figuring of that mirror meant that the Paris Observatory's 122 cm telescope was not used and did not have a good reputation for viewing.<ref name=":1">{{Cite book|url=https://books.google.com/books?id=bWRbAQAAQBAJ&q=paris+122+cm+reflector&pg=PT137|title=The Great Melbourne Telescope|last=Gillespie|first=Richard|date=2011-11-01|publisher=Museum Victoria|isbn=9781921833298|language=en}}</ref> The potential of metal coated glass became more apparent A.A. Common's 36 inch reflecting telescope by 1878.<ref name=":1" /> (this won an astrophotography award)

The Warner and Swasey equatorial mount was shown in Chicago at the 1893 Colombia Exhibition, before it was moved to the Observatory.<ref name=":2"/>

;Largest telescopes (all types) in 1910)
{| class="wikitable sortable" style="font-size:95%;"
! Name/Observatory
! class="unsortable" |[[Aperture]] cm (in)
! [[Telescope|Type]]
! Location
! Extant or Active
|-style="background:#CCFFFF"
| Harvard 60-inch Reflector<ref name="auto">{{Cite web |url=https://query.nytimes.com/gst/abstract.html?res=9A0CE3DC143AE733A25755C0A9629C946497D6CF |title=New York Times "NEW HARVARD TELESCOPE.; Sixty-Inch Reflector, Biggest in the World, Being Set Up. "April 6, 1905, Thursday", Page 9 |access-date=February 10, 2017 |archive-url=https://web.archive.org/web/20160810055322/http://query.nytimes.com/gst/abstract.html?res=9A0CE3DC143AE733A25755C0A9629C946497D6CF |archive-date=August 10, 2016 |url-status=live }}</ref> || 1.524 m (60″) || [[Silver on glass|reflector – glass]] || [[Harvard College Observatory]], USA || 1905–1931
|-style="background:#CCFFFF"
| [[Mount Wilson Observatory|Hale 60-Inch Telescope]] || 1.524 m (60″) || [[Silver on glass|reflector – glass]] || [[Mt. Wilson Observatory]]; [[California]] || 1908
|-style="background:#CCFFFF"
| National Observatory, Paris || 122 cm (48″) || [[Silver on glass|reflector – glass]] || Paris, France || 1875–1943<ref name=page250/>
|- style="background:#F0FFFF"
| [[Great Melbourne Telescope]]<ref name="stjarnhimlen.se"/> || 122 cm (48″) || [[Speculum metal|reflector – metal]] || [[Melbourne Observatory]], Australia || 1878
|- style="background:#DAF7A6"
| Yerkes Observatory<ref name="ReferenceA"/> || 102 cm (40″) || achromat || [[Williams Bay, Wisconsin]], [[United States|USA]] || 1897
|-
|-style="background:#CCFFFF"
| Meudon Observatory 1m<ref name="auto1"/>|| 100 cm (39.4″) || reflector-glass || Meudon Observatory/ Paris Observatory || 1891 <ref name="auto3"/>
|-
|[[James Lick telescope]], [[Lick Observatory]] || 91 cm (36″) || achromat || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1888
|- style="background:#CCFFFF"
| [[Crossley telescope|Crossley Reflector]]<ref name="ucolick.org"/> (Lick Observatory) || 91.4 cm (36″) || [[Silver on glass|reflector – glass]] || [[Mount Hamilton (California)|Mount Hamilton, California]], [[United States|USA]] || 1896
|}

==Legacy==
[[File:Titan in true color.jpg|thumb|The Atmosphere of Saturn's moon Titan (''pictured'') was discovered by Kuiper while working at the Yerkes Observatory—a moon that would later be visited by Voyager 1 and also the Cassini-Huygens spacecraft.]]
By 1905, the largest telescope in the World was the Harvard 60-inch Reflector ( 1.524 m 60″) at [[Harvard College Observatory]], USA.<ref name="auto"/> Then in 1908, [[Mount Wilson Observatory]] matched that size with a 60-inch reflector of their own, and throughout the 20th century, increasingly larger reflectors would be established, aided also by refinements to mirror technology{{mdash}} vapor-deposited aluminum on low-thermal expansion glass, pioneered for the 200 inch (5 meter) Hale telescope of 1948.<ref>{{Cite web|url=http://www.astro.caltech.edu/palomar/about/telescopes/hale.html|title=The 200-inch Hale Telescope|website=www.astro.caltech.edu}}</ref>

In the latter years of the 20th century, space observatories also marked a major advance, and somewhat less than a century after Yerkes, the Hubble Space Telescope, with a 2.4 meter reflector, was launched. Small refractors remain popular for astronaut photography, although issues with chromatic aberration were never really entirely solved for the lens. (Isaac Newton had solved this with the reflecting design, although the refactors are not without their merits.)

The renaissance-esque grounds<ref>{{Cite web|url=http://www-news.uchicago.edu/releases/06/060607.yerkes.shtml|title=Agreement provides for preservation of historic Yerkes Observatory|website=www-news.uchicago.edu|access-date=2020-03-03}}</ref> and architecture, murals, and statues of the premiere 19th century great observatories, with their extraordinary great telescopes; the Yerkes facility was described as "castle-like".<ref>{{Cite web|url=https://www.skyandtelescope.com/astronomy-news/not-quite-closing-yerkes-observatory/|title=The Not-Quite Closing of Yerkes Observatory|date=2018-03-16|website=Sky & Telescope|language=en-US|access-date=2019-10-02}}</ref> For example, the Yerkes Observatory was built on a 77-acre grounds, with artistically designed landscaping.<ref name="Science">{{Cite web|url=https://www.space.com/26858-yerkes-observatory.html|title=Yerkes Observatory: Home of Largest Refracting Telescope|last1=Science|first1=Elizabeth Howell 2014-08-16T02:26:07Z|last2=Astronomy|website=Space.com|language=en|access-date=2019-10-02}}</ref><ref name=":0" /> The visually remarkable extremely long tubes and elaborate domes and mounts provided an egg of knowledge that astronomers and the public flocked to for knowledge about the stars. The Yerkes grounds have landscaping designed by Olmstead, for example.<ref name=":0">{{Cite web|url=http://www-news.uchicago.edu/releases/06/060607.yerkes.shtml|title=Agreement provides for preservation of historic Yerkes Observatory|website=www-news.uchicago.edu|access-date=2019-10-02}}</ref>

Great advancements such as [[astrophotography]] and the discovery of nebulas and different types of stars provided a major advance in this period. The importance of finely crafted mounts matched to a large aperture, harnessing the power of the basic equations of the telescopes design to bring the heavens into closer, brighter examination increased humankind's understanding of space and Earth's place in the Galaxy. Among the accomplishments, Kuiper discovered that Saturn's Moon [[Titan (moon)|Titan]] has an atmosphere.<ref name="Science"/>

[[File:Yerkes Observatory Rear.jpg|thumb|left|600px|Panorma of the Observatory building, 2016]]
{{clear}}

==See also==
*[[List of largest optical refracting telescopes]]
*[[List of astronomical observatories]]
* [[List of largest optical telescopes in the 20th century]]
* [[List of largest optical telescopes in the 19th century]]
*[[Yerkes 41-inch reflector]]

==References==
{{Reflist|3}}

==External links==
{{commons category-inline}}
*[http://www.cr.nps.gov/history/online_books/butowsky5/astro4p.htm Description and history] from the [[National Park Service]].
*[http://www.saveyerkes.com/ Save Yerkes]
*[https://web.archive.org/web/20070325192503/http://yerkes.uchicago.edu/ysg/ Yerkes Study Group]
*[http://www.genevalakeconservancy.org Geneva Lake Conservancy]
*[https://www.glaseducation.org/about.html/ GLAS]
*[https://www.lib.uchicago.edu/e/scrc/findingaids/view.php?eadid=ICU.SPCL.YERKESLOGS Guide to the University of Chicago Yerkes Observatory Logbooks and Notebooks 1892-1988] at the [https://www.lib.uchicago.edu/scrc/ University of Chicago Special Collections Research Center]
*[https://www.lib.uchicago.edu/e/scrc/findingaids/view.php?eadid=ICU.SPCL.YERKESOFCDIR Guide to the University of Chicago, Yerkes Observatory, Office of the Director Records 1891-1946] at the [https://www.lib.uchicago.edu/scrc/ University of Chicago Special Collections Research Center]

{{UChicago}}

[[Category:Astronomical observatories in Wisconsin]]
[[Category:Research institutes of the University of Chicago]]
[[Category:Buildings and structures in Walworth County, Wisconsin]]

Astronomical survey

2020-11-03T06:03:56Z

Blastr42: Added info about astrographic catalogue

{{short description|General map or image of a region of the sky with no specific observational target.}}
[[File:GOODS-South field.jpg|thumb|Composite image of the GOODS-South field, result of a deep survey using two of the four giant 8.2-metre telescopes composing [[ESO]]'s [[Very Large Telescope]]]]
[[File:Fermi's Gamma-ray Pulsars.jpg|thumb|Gamma-ray pulsars detected by the Fermi Gamma-ray Space Telescope]]

An '''astronomical survey''' is a general [[celestial cartography|map]] or [[astrophotography|image]] of a region of the [[sky]] that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of many images or spectra of objects that share a common type or feature. Surveys are often restricted to one band of the [[electromagnetic spectrum]] due to instrumental limitations, although multiwavelength surveys can be made by using multiple detectors, each sensitive to a different bandwidth.<ref>See, for example, {{cite journal |authors=Lacy, M., Riley, J. M., Waldram, E. M., McMahon, R. G., & Warner, P. J. |year=1995 |title=A radio-optical survey of the North Ecliptic CAP |journal=Monthly Notices of the Royal Astronomical Society |volume=276 |issue=2 |pages=614–626|bibcode=1995MNRAS.276..614L |doi=10.1093/mnras/276.2.614 |doi-access=free }}</ref>

Surveys have generally been performed as part of the production of an [[astronomical catalog]]. They may also search for [[transient astronomical event]]s. They often use wide-field [[astrograph]]s.

== Scientific value ==
Sky surveys, unlike targeted observation of a specific object, allow astronomers to catalog celestial objects and perform statistical analyses on them without making prohibitively lengthy observations. In some cases, an astronomer interested in a particular object will find that survey images are sufficient to make telescope time entirely unnecessary.

Surveys also help astronomers choose targets for closer study using larger, more powerful telescopes. If previous observations support a hypothesis, a telescope scheduling committee is more likely to approve new, more detailed observations to test it.

The wide scope of surveys makes them ideal for finding foreground objects that move, such as asteroids and comets. An astronomer can compare existing survey images to current observations to identify changes; this task can even be performed automatically using [[image analysis]] software. Besides science, these surveys also detect [[potentially hazardous object]]s. Similarly, images of the same object taken by different surveys can be compared to detect [[transient astronomical event]]s such as variable stars.<ref>{{cite podcast|first1=Dr. Pamela|last1=Gay|authorlink1=Pamela L. Gay|first2=Fraser|last2=Cain|date=26 May 2008|website=[[Astronomy Cast]]|title=''Episode #90: The Scientific Method''|url=http://media.libsyn.com/media/astronomycast/AstroCast-080526.mp3|accessdate=16 Dec 2009}}</ref>

== List of sky surveys ==
[[File:A large slice of the Universe.jpg|thumb|The positions in space of just some of the galaxies identified by the VIPERS survey.<ref>{{cite web|title=3D Map of Distant Galaxies Completed – VLT survey shows distribution in space of 90 000 galaxies|url=https://www.eso.org/public/announcements/ann16086/|website=www.eso.org|accessdate=16 December 2016}}</ref>]]

{{See also|Category:Astronomical surveys}}

* Optical
**[[Carte du Ciel|Astrographic Catalogue]] - first international astronomical survey of the entire sky. The survey was performed by 18 observatories using over 22,000 photographic plates. The results have been the basis of comparison for all subsequent surveys, 1887-1975.
**[[Catalina Sky Survey]] - an astronomical survey to discover comets and asteroids.
** [[Pan-Andromeda Archaeological Survey]]
** [[National Geographic Society – Palomar Observatory Sky Survey]] (NGS–POSS) – survey of the northern sky on photographic plates, 1948–1958
** [[CfA Redshift Survey]] – A program from Harvard-Smithonian Center for Astrophysics. It began in 1977 to 1982 then from 1985 to 1995.
** [[Digitized Sky Survey]] – optical all-sky survey created from digitized photographic plates, 1994
** [[2dF Galaxy Redshift Survey]] (2dfGRS) – redshift survey conducted by the Anglo-Australian Observatory between 1997 and 2002
** [[Sloan Digital Sky Survey]] (SDSS) – an optical and spectroscopic survey, 2000–2006 (first pass)
** [[Photopic Sky Survey]] – a survey with 37,440 individual exposures, 2010–2011.<ref>{{cite web|last=Risinger|first=Nick|title=Phototopic Sky Survey|url=http://skysurvey.org/|accessdate=12 May 2011}}</ref><ref>{{cite news|last=Associated Press|title=Amateur Photographer Links 37,000 Pics in Night-Sky Panorama|url=http://www.foxnews.com/scitech/2011/05/12/amateur-photographer-links-37000-pics-night-sky-panorama/|accessdate=13 May 2011|work=Fox News|date=12 May 2011}}</ref>
** [[DEEP2 Redshift Survey]] (DEEP2) – Used [[Keck Telescopes]] to measure redshift of 50,000 galaxies
** [[VIMOS-VLT Deep Survey]] (VVDS) – Franco-Italian study using the [[Very Large Telescope]] at [[Paranal Observatory]]
** [[Palomar Distant Solar System Survey]] (PDSSS)
** [[WiggleZ Dark Energy Survey]]<ref>{{cite web|url=http://wigglez.swin.edu.au/site/ |title=WiggleZ Dark Energy Survey | Home |publisher=Wigglez.swin.edu.au |date= |accessdate=2014-03-03}}</ref> (2006–2011) used the [[Australian Astronomical Observatory]]
** [[Dark Energy Survey]] (DES)<ref>{{cite web|url=http://www.darkenergysurvey.org/ |title=darkenergysurvey.org |publisher=darkenergysurvey.org |date= |accessdate=2014-03-03}}</ref> is a survey about one-tenth of the sky to find clues to the characteristics of dark energy.-
** [[Calar Alto Legacy Integral Field Area Survey]] (CALIFA) – a spectroscopic survey of galaxies
** [[SAGES Legacy Unifying Globulars and GalaxieS Survey|SAGES Legacy Unifying Globulars and GalaxieS]] ([[SAGES Legacy Unifying Globulars and GalaxieS Survey]] (SLUGGS) survey<ref>{{Cite web|url = http://sluggs.swin.edu.au/|title = SLUGGS survey webpage|date = |accessdate = |website = |publisher = |last = |first = }}</ref> – a near-infrared spectro-photometric survey of 25 nearby [[early-type galaxies]] (2014)
** [[LAMOST|Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)]]<ref>{{Cite web|url = http://www.lamost.org/|title = LAMOST survey webpage|date = |accessdate = |website = |publisher = |last = |first = }}</ref> – an extra-galactic and stellar spectroscopic survey
** [[The INT Photometric H-Alpha Survey|IPHAS]] and VPHAS+ – surveys of the Galactic bulge and inner disk using the Isaac Newton Telescope (north) and VLT Survey Telescope (south) in u, g, r, Hα, and i bands, 2003–present
** [[Pan-STARRS]] – a proposed 4-telescope large-field survey system to look for transient and variable sources
** [[Optical Gravitational Lensing Experiment]] (OGLE) – large-scale variability sky survey (in I and V bands), 1992-present
** [[Dark Energy Spectroscopic Instrument#DESI Legacy Imaging Surveys|DESI Legacy Imaging Surveys]] (Legacy Surveys) - large imaging survey of the extragalactic sky, in three bands and covering one third of the sky, 2013-present
* Infrared [[File:Massive galaxies discovered in the early Universe.jpg|thumb|Massive galaxies discovered in the early Universe of the UltraVISTA field.<ref>{{cite web|title=The Birth of Monsters|url=http://www.eso.org/public/news/eso1545/|accessdate=14 December 2015}}</ref>]]
** [[IRAS|Infrared Astronomical Satellite]] did an all sky survey at 12, 25, 60, and 100 μm, 1983
** [[2MASS|The 2-micron All-Sky Survey]] (2MASS), a ground-based all sky survey at J, H, and Ks bands (1.25, 1.65, and 2.17 μm) 1997–2001
** [[Akari (Astro-F)]] a Japanese mid and far infrared all-sky survey satellite, 2006–2008
** [[WISE mission|Wide-field Infrared Survey Explorer]] (WISE) was launched in December 2009 to begin a survey of 99% of the sky at wavelengths of 3.3, 4.7, 12, and 23 μm. The telescope is over a thousand times as sensitive as previous infrared surveys. The initial survey, consisting of each sky position imaged at least eight times, was completed by July 2010.
** [[UKIRT Infrared Deep Sky Survey]] (UKIDSS) – a collection of ground based northern hemisphere surveys (GPS, GCS, LAS, DXS, UDS) using the [[WFCAM]] camera on [[UKIRT]], some wide and some very deep, in Z, Y, J, H, & K bands 2005–
** [[VISTA (telescope)|VISTA]] public surveys – a collection of ground based southern hemisphere surveys ([[Vista Variables in the Via Lactea|VVV]], VMC, VHS, VIKING, VIDEO, UltraVISTA), of various areas and depths, in Z, Y, J, H, & Ks bands, 2009–present
** [[SCUBA-2 All Sky Survey]]
* Radio
**[[HIPASS]] – Radio survey, the first blind [[hydrogen line|HI]] survey to cover the entire [[celestial hemisphere|southern sky]]. 1997–2002
** [[Ohio Sky Survey]] – Over 19,000 radio sources at 1415 MHz. 1965–1973.
** [[NRAO VLA Sky Survey|NVSS]] – Survey at 1.4 GHz mapping the sky north of −40 deg
** [[Faint Images of the Radio Sky at Twenty-Centimeters|FIRST]] – Survey to look for faint radio sources at twenty cms.<ref>{{cite web|url=http://sundog.stsci.edu/index.html |title=The VLA FIRST Survey |publisher=Sundog.stsci.edu |date=2008-07-21 |accessdate=2014-03-03}}</ref>
** [[PALFA Survey]] – On-going 1.4 GHz survey for radio [[pulsar]]s using the [[Arecibo Observatory]].
** [[GALEX Arecibo SDSS Survey]] GASS<ref>{{cite web|url=http://www.mpa-garching.mpg.de/GASS/index.php |title=The GALEX Arecibo SDSS Survey |publisher=Mpa-garching.mpg.de |date= |accessdate=2014-03-03}}</ref> designed to measure the neutral hydrogen content of a representative sample of ~1000 massive, galaxies
** [[C-Band All Sky Survey|C-BASS]] – On-going 5 GHz all sky survey to aid in the subtraction of galactic foregrounds from maps of the [[Cosmic Microwave Background]]
** [[Evolutionary_Map_of_the_Universe|EMU]] – A large radio continuum survey covering 3/4 of the sky, expected to discover about 70 million galaxies
** [[Giant Metrewave Radio Telescope|GMRT]] - The Giant Metrewave Radio Telescope's TGSS ADR mapped the sky at 150 MHz.
**[[High Time Resolution Universe|HTRU]] – A pulsar and radio transients survey of the northern and southern sky using the Parkes Radio Telescope and the Effelsberg telescope.

* Gamma-ray
** [[Fermi Gamma-ray Space Telescope]], formerly referred to as the "Gamma-ray Large Area Space Telescope (GLAST)." 2008–present; the goal for the telescope's lifetime is 10 years.
* Multi-wavelength surveys
** [[Galaxy And Mass Assembly survey|GAMA]] – the Galaxy And Mass Assembly survey<ref>[http://gama-survey.org gama-survey.org]</ref> combines data from a number of ground- and space-based observatories together with a large [[redshift survey]], performed at the [[Anglo-Australian Telescope]]. The resulting dataset aims to be a comprehensive resource for studying the physics of the galaxy population and underlying mass structures in the recent universe.<ref>{{cite journal |bibcode=2009A&G....50e..12D |title=GAMA: towards a physical understanding of galaxy formation |journal= [[Astronomy & Geophysics]] |volume=50 |issue=5 |pages=5.12 |arxiv=0910.5123 |doi=10.1111/j.1468-4004.2009.50512.x |last1=Driver |first1=Simon P. |last2=Norberg |first2=Peder |last3=Baldry |first3=Ivan K. |last4=Bamford |first4=Steven P. |last5=Hopkins |first5=Andrew M. |last6=Liske |first6=Jochen |last7=Loveday |first7=Jon |last8=Peacock |first8=John A. |last9=Hill |first9=D. T. |last10=Kelvin |first10=L. S. |last11=Robotham |first11=A. S. G. |last12=Cross |first12=N. J. G. |last13=Parkinson |first13=H. R. |last14=Prescott |first14=M. |last15=Conselice |first15=C. J. |last16=Dunne |first16=L. |last17=Brough |first17=S. |last18=Jones |first18=H. |last19=Sharp |first19=R. G. |last20=Van Kampen |first20=E. |last21=Oliver |first21=S. |last22=Roseboom |first22=I. G. |last23=Bland-Hawthorn |first23=J. |last24=Croom |first24=S. M. |last25=Ellis |first25=S. |last26=Cameron |first26=E. |last27=Cole |first27=S. |last28=Frenk |first28=C. S. |last29=Couch |first29=W. J. |last30=Graham |first30=A. W. |display-authors=29 |year=2009 }}</ref>
** [[Great Observatories Origins Deep Survey|GOODS]] – The Great Observatories Origins Deep Survey.
** COSMOS – The [[Cosmic Evolution Survey]]
** (The latter two surveys are joining together observations obtained from space with the [[Hubble Space Telescope]], the [[Spitzer Space Telescope]], the [[Chandra X-ray Observatory]] and the [[XMM-Newton]] satellite, with a large set of observations obtained with ground-based telescopes).
** [[Atlas 3d survey|Atlas 3d Survey]] – sample of 260 galaxies for the Astrophysics project.<ref>{{cite web|url=http://www-astro.physics.ox.ac.uk/atlas3d/ |title=Atlas3D Survey |publisher=Astro.physics.ox.ac.uk |date= |accessdate=2014-03-03}}</ref>
* Planned
** [[Large Synoptic Survey Telescope]] – a proposed very large telescope designed to repeatedly survey the whole sky that is visible from its location
** [[ASKAP]] HI All Sky Survey (WALLABY) – PI [[Bärbel Koribalski]]

=== Surveys of the Magellanic Clouds ===
* [[MCELS (Magellanic Cloud Emission-line Survey)]]
* [[The Magellanic Clouds Photometric Survey]] – UBVI (optical)
* [[Deep Near Infrared Survey]] (DENIS) – near-IR

== See also ==
{{Commons category|Astronomical catalogues and surveys}}
* See [[astronomical catalogue]] for a more detailed description of astronomical surveys and the production of astronomical catalogues
* [[Redshift survey]]s are astronomical surveys devoted to mapping the cosmos in three dimensions
* [[:Category:astronomical catalogues]]—List of astronomical catalogues on Wikipedia
* [[Astrograph]] for a type of instrument used in Astronomical surveys.
* [[Timeline of astronomical maps, catalogs, and surveys]]

== References ==
{{Reflist}}

[[Category:Astronomical surveys| ]]
[[Category:Astronomical imaging]]
[[Category:Observational astronomy]]
[[Category:Works about astronomy| Survey]]

Infrared telescope

2020-10-22T16:55:54Z

Blastr42: Updated name for WFIRST to Roman Space Telescope

[[File:WyomingInfraRedObservatory.jpg|thumb|Wyoming Infrared Observatory]]
[[File:SOFIA with open telescope doors.jpg|thumb|[[SOFIA]] is an infrared telescope in an aircraft, allowing high altitude observations]]

An '''infrared telescope''' is a [[telescope]] that uses [[infrared]] light to detect celestial bodies. Infrared light is one of several types of radiation present in the [[electromagnetic spectrum]].

All celestial objects with a temperature above [[absolute zero]] emit some form of [[electromagnetic radiation]].<ref>[http://www.jpl.nasa.gov/news/press_kits/sirtflaunch.pdf SPACE OBSERVATORY TO STUDY THE FAR, THE COLD AND THE DUSTY], NASA press kit, 2003</ref> In order to study the universe, scientists use several different types of telescopes to detect these different types of emitted radiation in the electromagnetic spectrum. Some of these are [[gamma ray]], [[x-ray]], [[ultra-violet]], regular [[visible light]] (optical), as well as infrared telescopes.

== Leading discoveries ==
There were several key developments that led to the invention of the infrared telescope:
* In 1800, [[William Herschel]] discovered infrared radiation.
* In 1878, [[Samuel Pierpoint Langley]] created the first [[bolometer]]. This was a very sensitive instrument that could electrically detect incredibly small changes in temperature in the infrared spectrum.
* Thomas Edison used an alternative technology, his [[tasimeter]], to measure heat in the sun's [[solar corona|corona]] during the [[solar eclipse of July 29, 1878]].
* In the 1950s, scientists used lead-sulfide detectors to detect the infrared radiation from space. These detectors were cooled with [[liquid nitrogen]].
* Between 1959 and 1961, [[Harold Johnson (astronomer)|Harold Johnson]] created near-infrared [[photometer]]s which allowed scientists to measure thousands of stars.
* In 1961, [[Frank Low]] invented the first [[germanium]] bolometer. This invention, cooled by [[liquid helium]], led the way for current infrared telescope development.<ref name="caltech_timeline">[http://www.ipac.caltech.edu/Outreach/Edu/Timeline/timeline2.html Timeline] {{webarchive|url=https://web.archive.org/web/20100618102530/http://www.ipac.caltech.edu/Outreach/Edu/Timeline/timeline2.html |date=2010-06-18 }} Caltech</ref>

Infrared telescopes may be ground-based, air-borne, or [[space telescope]]s. They contain an infrared camera with a special solid-state infrared detector which must be cooled to [[cryogenics|cryogenic]] temperatures.<ref>http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ask_astronomer/faq/obs.shtml</ref>

Ground-based telescopes were the first to be used to observe outer space in infrared. Their popularity increased in the mid-1960s. Ground-based telescopes have limitations because [[water vapor]] in the Earth's atmosphere absorbs infrared radiation. Ground-based infrared telescopes tend to be placed on high mountains and in very dry climates to improve visibility.

In the 1960s, scientists used balloons to lift infrared telescopes to higher altitudes. With balloons, they were able to reach about {{convert|25|mi|km|0|abbr=off}} up. In 1967, infrared telescopes were placed on rockets.<ref name="caltech_timeline"/> These were the first air-borne infrared telescopes. Since then, aircraft like the [[Kuiper Airborne Observatory]] (KAO) have been adapted to carry infrared telescopes. A more recent air-borne infrared telescope to reach the stratosphere was NASA's [[Stratospheric Observatory for Infrared Astronomy]] (SOFIA) in May 2010. Together, United States scientists and the German Aerospace Center scientists placed a 17-ton infrared telescope on a [[Boeing 747]] jet airplane.<ref>Hamilton, J. (2010, July 2) NASA's flying telescope sees early success. ''National Public Radio''. Retrieved from https://www.npr.org/templates/story/story.php?storyId=128015118</ref>

Placing infrared telescopes in space completely eliminates the interference from the Earth's atmosphere. One of the most significant infrared telescope projects was the [[Infrared Astronomical Satellite]] (IRAS) that launched in 1983. It revealed information about other galaxies, as well as information about the center of our galaxy the Milky Way.<ref name="caltech_timeline"/> NASA presently has solar-powered spacecraft in space with an infrared telescope called the [[Wide-field Infrared Survey Explorer]] (WISE). It was launched on December 14, 2009.<ref>Griggs, B. (2009, December 14) NASA launches infrared telescope to scan entire sky. ''Cable News Network''. Retrieved from http://www.cnn.com/2009/TECH/space/12/14/wise.spacecraft.launch/index.html</ref>

==Selective comparison==
[[File:IRAS overview.jpg|thumb|250px]]

Visible light is about 0.4 μm to 0.7 μm, and 0.75 μm to 1000 μm (1 mm) is a typical range for [[infrared astronomy]], [[far-infrared astronomy]], to [[submillimetre astronomy]].

<div style="align:left; margin:2px;">
{| class=wikitable style="text-align:center; font-size:11px"
|- bgcolor= style="font-size: smaller;"
| colspan=8 align=center|'''Selected infrared space telescopes'''<ref>[http://herschel.jpl.nasa.gov/relatedMissions.shtml JPL: Herschel Space Observatory: Related Missions]</ref>
|-
! Name !! Year || Wavelength
|-
| [[IRAS]] || 1983 || 5–100 μm
|-
| [[Infrared Space Observatory|ISO]] || 1996 || 2.5–240 μm
|-
| [[Spitzer Space Telescope|Spitzer]] || 2003 || 3–180 μm
|-
| [[Akari (Astro-F)|Akari]] || 2006 || 2–200 μm
|-
| [[Herschel Space Observatory|Herschel]] || 2009 || 55–672 μm
|-
| [[Wide-field Infrared Survey Explorer|WISE]] || 2010 || 3–25 μm
|-
| [[James Webb Space Telescope|JWST]] || Planned || 0.6–28.5 μm
|-
|}
</div>

==Infrared telescopes==
Ground based :
* [[Infrared Telescope Facility]], Hawaii, 1979–
* [[Gornergrat Infrared Telescope]], 1979–2005
* [[Infrared Optical Telescope Array]], 1988–2006
* [[United Kingdom Infrared Telescope]], 1979–
Airborne:
* [[Kuiper Airborne Observatory]] (KAO), 1974-1995
*[[Stratospheric Observatory for Infrared Astronomy]] (SOFIA), 2010-
Space based:
* [[Spitzer Space Telescope]], 2003-2020
* [[Herschel Space Observatory]], 2009-2013
* [[Wide-field Infrared Survey Explorer]] (WISE), 2009-
* [[Roman Space Telescope]] (formerly WFIRST)
* [[James Webb Space Telescope]]

==See also==
* [[Infrared astronomy]]
* [[List of largest infrared telescopes]]
* [[List of telescope types]]

==Notes==
{{Commons category|Infrared telescopes}}
{{reflist}}

[[Category:Infrared telescopes| ]]
[[Category:Telescope types]]
[[Category:Infrared imaging]]

Infrared telescope

2020-10-22T16:52:07Z

Blastr42: Added KAO and SOFIA links at the end.

[[File:WyomingInfraRedObservatory.jpg|thumb|Wyoming Infrared Observatory]]
[[File:SOFIA with open telescope doors.jpg|thumb|[[SOFIA]] is an infrared telescope in an aircraft, allowing high altitude observations]]

An '''infrared telescope''' is a [[telescope]] that uses [[infrared]] light to detect celestial bodies. Infrared light is one of several types of radiation present in the [[electromagnetic spectrum]].

All celestial objects with a temperature above [[absolute zero]] emit some form of [[electromagnetic radiation]].<ref>[http://www.jpl.nasa.gov/news/press_kits/sirtflaunch.pdf SPACE OBSERVATORY TO STUDY THE FAR, THE COLD AND THE DUSTY], NASA press kit, 2003</ref> In order to study the universe, scientists use several different types of telescopes to detect these different types of emitted radiation in the electromagnetic spectrum. Some of these are [[gamma ray]], [[x-ray]], [[ultra-violet]], regular [[visible light]] (optical), as well as infrared telescopes.

== Leading discoveries ==
There were several key developments that led to the invention of the infrared telescope:
* In 1800, [[William Herschel]] discovered infrared radiation.
* In 1878, [[Samuel Pierpoint Langley]] created the first [[bolometer]]. This was a very sensitive instrument that could electrically detect incredibly small changes in temperature in the infrared spectrum.
* Thomas Edison used an alternative technology, his [[tasimeter]], to measure heat in the sun's [[solar corona|corona]] during the [[solar eclipse of July 29, 1878]].
* In the 1950s, scientists used lead-sulfide detectors to detect the infrared radiation from space. These detectors were cooled with [[liquid nitrogen]].
* Between 1959 and 1961, [[Harold Johnson (astronomer)|Harold Johnson]] created near-infrared [[photometer]]s which allowed scientists to measure thousands of stars.
* In 1961, [[Frank Low]] invented the first [[germanium]] bolometer. This invention, cooled by [[liquid helium]], led the way for current infrared telescope development.<ref name="caltech_timeline">[http://www.ipac.caltech.edu/Outreach/Edu/Timeline/timeline2.html Timeline] {{webarchive|url=https://web.archive.org/web/20100618102530/http://www.ipac.caltech.edu/Outreach/Edu/Timeline/timeline2.html |date=2010-06-18 }} Caltech</ref>

Infrared telescopes may be ground-based, air-borne, or [[space telescope]]s. They contain an infrared camera with a special solid-state infrared detector which must be cooled to [[cryogenics|cryogenic]] temperatures.<ref>http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ask_astronomer/faq/obs.shtml</ref>

Ground-based telescopes were the first to be used to observe outer space in infrared. Their popularity increased in the mid-1960s. Ground-based telescopes have limitations because [[water vapor]] in the Earth's atmosphere absorbs infrared radiation. Ground-based infrared telescopes tend to be placed on high mountains and in very dry climates to improve visibility.

In the 1960s, scientists used balloons to lift infrared telescopes to higher altitudes. With balloons, they were able to reach about {{convert|25|mi|km|0|abbr=off}} up. In 1967, infrared telescopes were placed on rockets.<ref name="caltech_timeline"/> These were the first air-borne infrared telescopes. Since then, aircraft like the [[Kuiper Airborne Observatory]] (KAO) have been adapted to carry infrared telescopes. A more recent air-borne infrared telescope to reach the stratosphere was NASA's [[Stratospheric Observatory for Infrared Astronomy]] (SOFIA) in May 2010. Together, United States scientists and the German Aerospace Center scientists placed a 17-ton infrared telescope on a [[Boeing 747]] jet airplane.<ref>Hamilton, J. (2010, July 2) NASA's flying telescope sees early success. ''National Public Radio''. Retrieved from https://www.npr.org/templates/story/story.php?storyId=128015118</ref>

Placing infrared telescopes in space completely eliminates the interference from the Earth's atmosphere. One of the most significant infrared telescope projects was the [[Infrared Astronomical Satellite]] (IRAS) that launched in 1983. It revealed information about other galaxies, as well as information about the center of our galaxy the Milky Way.<ref name="caltech_timeline"/> NASA presently has solar-powered spacecraft in space with an infrared telescope called the [[Wide-field Infrared Survey Explorer]] (WISE). It was launched on December 14, 2009.<ref>Griggs, B. (2009, December 14) NASA launches infrared telescope to scan entire sky. ''Cable News Network''. Retrieved from http://www.cnn.com/2009/TECH/space/12/14/wise.spacecraft.launch/index.html</ref>

==Selective comparison==
[[File:IRAS overview.jpg|thumb|250px]]

Visible light is about 0.4 μm to 0.7 μm, and 0.75 μm to 1000 μm (1 mm) is a typical range for [[infrared astronomy]], [[far-infrared astronomy]], to [[submillimetre astronomy]].

<div style="align:left; margin:2px;">
{| class=wikitable style="text-align:center; font-size:11px"
|- bgcolor= style="font-size: smaller;"
| colspan=8 align=center|'''Selected infrared space telescopes'''<ref>[http://herschel.jpl.nasa.gov/relatedMissions.shtml JPL: Herschel Space Observatory: Related Missions]</ref>
|-
! Name !! Year || Wavelength
|-
| [[IRAS]] || 1983 || 5–100 μm
|-
| [[Infrared Space Observatory|ISO]] || 1996 || 2.5–240 μm
|-
| [[Spitzer Space Telescope|Spitzer]] || 2003 || 3–180 μm
|-
| [[Akari (Astro-F)|Akari]] || 2006 || 2–200 μm
|-
| [[Herschel Space Observatory|Herschel]] || 2009 || 55–672 μm
|-
| [[Wide-field Infrared Survey Explorer|WISE]] || 2010 || 3–25 μm
|-
| [[James Webb Space Telescope|JWST]] || Planned || 0.6–28.5 μm
|-
|}
</div>

==Infrared telescopes==
Ground based :
* [[Infrared Telescope Facility]], Hawaii, 1979–
* [[Gornergrat Infrared Telescope]], 1979–2005
* [[Infrared Optical Telescope Array]], 1988–2006
* [[United Kingdom Infrared Telescope]], 1979–
Airborne:
* [[Kuiper Airborne Observatory]] (KAO), 1974-1995
*[[Stratospheric Observatory for Infrared Astronomy]] (SOFIA), 2010-
Space based:
* [[Spitzer Space Telescope]], 2003-2020
* [[Herschel Space Observatory]], 2009-2013
* [[Wide-field Infrared Survey Explorer]] (WISE), 2009-
* [[Wide Field Infrared Survey Telescope]] (WFIRST)
* [[James Webb Space Telescope]]

==See also==
* [[Infrared astronomy]]
* [[List of largest infrared telescopes]]
* [[List of telescope types]]

==Notes==
{{Commons category|Infrared telescopes}}
{{reflist}}

[[Category:Infrared telescopes| ]]
[[Category:Telescope types]]
[[Category:Infrared imaging]]

Infrared telescope

2020-10-22T16:46:26Z

Blastr42: Added link to KAO

[[File:WyomingInfraRedObservatory.jpg|thumb|Wyoming Infrared Observatory]]
[[File:SOFIA with open telescope doors.jpg|thumb|[[SOFIA]] is an infrared telescope in an aircraft, allowing high altitude observations]]

An '''infrared telescope''' is a [[telescope]] that uses [[infrared]] light to detect celestial bodies. Infrared light is one of several types of radiation present in the [[electromagnetic spectrum]].

All celestial objects with a temperature above [[absolute zero]] emit some form of [[electromagnetic radiation]].<ref>[http://www.jpl.nasa.gov/news/press_kits/sirtflaunch.pdf SPACE OBSERVATORY TO STUDY THE FAR, THE COLD AND THE DUSTY], NASA press kit, 2003</ref> In order to study the universe, scientists use several different types of telescopes to detect these different types of emitted radiation in the electromagnetic spectrum. Some of these are [[gamma ray]], [[x-ray]], [[ultra-violet]], regular [[visible light]] (optical), as well as infrared telescopes.

== Leading discoveries ==
There were several key developments that led to the invention of the infrared telescope:
* In 1800, [[William Herschel]] discovered infrared radiation.
* In 1878, [[Samuel Pierpoint Langley]] created the first [[bolometer]]. This was a very sensitive instrument that could electrically detect incredibly small changes in temperature in the infrared spectrum.
* Thomas Edison used an alternative technology, his [[tasimeter]], to measure heat in the sun's [[solar corona|corona]] during the [[solar eclipse of July 29, 1878]].
* In the 1950s, scientists used lead-sulfide detectors to detect the infrared radiation from space. These detectors were cooled with [[liquid nitrogen]].
* Between 1959 and 1961, [[Harold Johnson (astronomer)|Harold Johnson]] created near-infrared [[photometer]]s which allowed scientists to measure thousands of stars.
* In 1961, [[Frank Low]] invented the first [[germanium]] bolometer. This invention, cooled by [[liquid helium]], led the way for current infrared telescope development.<ref name="caltech_timeline">[http://www.ipac.caltech.edu/Outreach/Edu/Timeline/timeline2.html Timeline] {{webarchive|url=https://web.archive.org/web/20100618102530/http://www.ipac.caltech.edu/Outreach/Edu/Timeline/timeline2.html |date=2010-06-18 }} Caltech</ref>

Infrared telescopes may be ground-based, air-borne, or [[space telescope]]s. They contain an infrared camera with a special solid-state infrared detector which must be cooled to [[cryogenics|cryogenic]] temperatures.<ref>http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ask_astronomer/faq/obs.shtml</ref>

Ground-based telescopes were the first to be used to observe outer space in infrared. Their popularity increased in the mid-1960s. Ground-based telescopes have limitations because [[water vapor]] in the Earth's atmosphere absorbs infrared radiation. Ground-based infrared telescopes tend to be placed on high mountains and in very dry climates to improve visibility.

In the 1960s, scientists used balloons to lift infrared telescopes to higher altitudes. With balloons, they were able to reach about {{convert|25|mi|km|0|abbr=off}} up. In 1967, infrared telescopes were placed on rockets.<ref name="caltech_timeline"/> These were the first air-borne infrared telescopes. Since then, aircraft like the [[Kuiper Airborne Observatory]] (KAO) have been adapted to carry infrared telescopes. A more recent air-borne infrared telescope to reach the stratosphere was NASA's [[Stratospheric Observatory for Infrared Astronomy]] (SOFIA) in May 2010. Together, United States scientists and the German Aerospace Center scientists placed a 17-ton infrared telescope on a [[Boeing 747]] jet airplane.<ref>Hamilton, J. (2010, July 2) NASA's flying telescope sees early success. ''National Public Radio''. Retrieved from https://www.npr.org/templates/story/story.php?storyId=128015118</ref>

Placing infrared telescopes in space completely eliminates the interference from the Earth's atmosphere. One of the most significant infrared telescope projects was the [[Infrared Astronomical Satellite]] (IRAS) that launched in 1983. It revealed information about other galaxies, as well as information about the center of our galaxy the Milky Way.<ref name="caltech_timeline"/> NASA presently has solar-powered spacecraft in space with an infrared telescope called the [[Wide-field Infrared Survey Explorer]] (WISE). It was launched on December 14, 2009.<ref>Griggs, B. (2009, December 14) NASA launches infrared telescope to scan entire sky. ''Cable News Network''. Retrieved from http://www.cnn.com/2009/TECH/space/12/14/wise.spacecraft.launch/index.html</ref>

==Selective comparison==
[[File:IRAS overview.jpg|thumb|250px]]

Visible light is about 0.4 μm to 0.7 μm, and 0.75 μm to 1000 μm (1 mm) is a typical range for [[infrared astronomy]], [[far-infrared astronomy]], to [[submillimetre astronomy]].

<div style="align:left; margin:2px;">
{| class=wikitable style="text-align:center; font-size:11px"
|- bgcolor= style="font-size: smaller;"
| colspan=8 align=center|'''Selected infrared space telescopes'''<ref>[http://herschel.jpl.nasa.gov/relatedMissions.shtml JPL: Herschel Space Observatory: Related Missions]</ref>
|-
! Name !! Year || Wavelength
|-
| [[IRAS]] || 1983 || 5–100 μm
|-
| [[Infrared Space Observatory|ISO]] || 1996 || 2.5–240 μm
|-
| [[Spitzer Space Telescope|Spitzer]] || 2003 || 3–180 μm
|-
| [[Akari (Astro-F)|Akari]] || 2006 || 2–200 μm
|-
| [[Herschel Space Observatory|Herschel]] || 2009 || 55–672 μm
|-
| [[Wide-field Infrared Survey Explorer|WISE]] || 2010 || 3–25 μm
|-
| [[James Webb Space Telescope|JWST]] || Planned || 0.6–28.5 μm
|-
|}
</div>

==Infrared telescopes==
Ground based :
* [[Infrared Telescope Facility]], Hawaii, 1979–
* [[Gornergrat Infrared Telescope]], 1979–2005
* [[Infrared Optical Telescope Array]], 1988–2006
* [[United Kingdom Infrared Telescope]], 1979–
Space based:
* [[Spitzer Space Telescope]], 2003-2020
* [[Herschel Space Observatory]], 2009-2013
* [[Wide-field Infrared Survey Explorer]] (WISE), 2009-
* [[Wide Field Infrared Survey Telescope]] (WFIRST)
* [[James Webb Space Telescope]]

==See also==
* [[Infrared astronomy]]
* [[List of largest infrared telescopes]]
* [[List of telescope types]]

==Notes==
{{Commons category|Infrared telescopes}}
{{reflist}}

[[Category:Infrared telescopes| ]]
[[Category:Telescope types]]
[[Category:Infrared imaging]]

Salyut programme

2020-09-12T19:04:41Z

Blastr42: /* DOS-2 */Explanatory text.

{{short description|Soviet space station programme}}
{{For|the aircraft engine manufacturer|Salyut Machine-Building Association}}
{{DISPLAYTITLE:''Salyut'' programme}}
{{more citations needed|date=August 2012}}
{{Use British English Oxford spelling|date=July 2019}}
{{Infobox space program
| name = ''Salyut'' programme
| image = Salyut program insignia.svg
| caption = ''Salyut'' programme insignia
| country = [[Soviet Union]]
| purpose = [[Space station]]
| status = Completed
| cost =
| duration = 1971–1986
| firstflight = [[Salyut 1|''Salyut'' 1]]
| firstcrewed = [[Soyuz 10]]
| lastflight = [[Soyuz T-15]]
| successes = 71
| failures = 10
| launchsite = [[Baikonur Cosmodrome|Baikonur]]
| vehicletype = Capsule
| crewvehicle = [[Soyuz (spacecraft)|Soyuz]]
| capacity = 2–3
| launcher = {{hlist|[[Proton-K]]|[[Soyuz (rocket)|Soyuz]]}}
}}
{{Soviet space program sidebar}}
The '''''Salyut'' programme''' ({{lang-ru|Салю́т}}, {{IPA-ru|sɐˈlʲut|IPA}}, meaning "salute" or "fireworks") was the first [[space station]] programme, undertaken by the [[Soviet Union]]. It involved a series of four crewed scientific research space stations and two crewed military reconnaissance space stations over a period of 15 years, from 1971 to 1986. Two other ''Salyut'' launches failed. In one respect, ''Salyut'' had the task of carrying out long-term research into the problems of living in space and a variety of astronomical, biological and Earth-resources experiments, and on the other hand the USSR used this civilian program as a cover for the highly secretive military ''[[Almaz]]'' stations, which flew under the ''Salyut'' designation. [[Salyut 1|''Salyut'' 1]], the first station in the program, became the world's first crewed space station.

''Salyut'' flights broke several [[spaceflight records]], including several mission-duration records, and achieved the first ever orbital handover of a space station from one crew to another, and various spacewalk records. The ensuing [[Soyuz programme]] was vital for evolving space station technology from a basic, engineering development stage, from single docking port stations to complex, multi-ported, long-term orbital outposts with impressive scientific capabilities, whose technological legacy continues {{as of|2020|lc=y}}. Experience gained from the ''Salyut'' stations paved the way for multimodular space stations such as ''[[Mir]]'' and the [[International Space Station]] (ISS), with each of those stations possessing a ''Salyut''-derived core module at its heart.

[[Mir-2|''Mir''-2]] (DOS-8), the final spacecraft from the ''Salyut'' series, became one of the first modules of the ISS. The first module of the ISS, the Russian-made ''[[Zarya]]'', relied heavily on technologies developed in the ''Salyut'' programme.<ref name="Ivanovich2008">{{cite book|author=Grujica S. Ivanovich|title=Salyut - The First Space Station: Triumph and Tragedy|url=https://books.google.com/books?id=EbDGMiXvdG0C|date=22 October 2008|publisher=Springer Science & Business Media|isbn=978-0-387-73973-1}}</ref>

==History of Salyut space stations==
{{multiple image|align=|header=
|width1=280|image1=Mir-33.jpg
|caption1= Development of the Soviet space stations:
* The large horizontal arrows trace the evolution of the two Soviet space station programs DOS (top) and Almaz-OPS (bottom)
* Dark gray arrows trace the infusions from the Soyuz and OPS programs to DOS
* Solid and dashed black arrows indicate modules intended for Mir, containing influences from OPS with the addition of space tugs
|footer=}}
The programme was composed of {{nowrap|'''DOS (Durable Orbital Station)'''}} civilian stations and {{nowrap|'''OPS (Orbital Piloted Station)'''}} military stations:

* The '''[[Almaz|Almaz-OPS]]''' space station cores were designed in October 1964 by [[Vladimir Chelomei]]'s [[OKB-52]] organization as military space stations, long before the Salyut programme started.<ref name="RSWalmaz">{{cite web |url=http://www.russianspaceweb.com/almaz.html |title=Russianspaceweb.com – The Almaz program}}</ref> For Salyut, small modifications had to be made to the docking port of the OPS to accommodate [[Soyuz spacecraft]] in addition to [[TKS spacecraft]].
* The civilian '''DOS''' space station cores were designed by [[Sergei Korolev]]'s [[OKB-1]] organization. Korolev and Chelomei had been in fierce competition in the Soviet space industry during the time of the [[Soviet crewed lunar programs#Moon landing N1/L3 program|Soviet crewed lunar programme]], but OKB-52's Almaz-OPS hull design was combined with subsystems derived from OKB-1's Soyuz.<ref name="Grahn">{{cite web |url=http://www.svengrahn.pp.se/trackind/salyut1/salyut1.html |title=Salyut 1, its origin |author=Sven Grahn}}</ref> This was done beginning with conceptual work in August 1969.<ref name="EAsalyut">{{cite web |url=http://www.astronautix.com/project/salyut.htm |title=Encyclopedia Astronautica – Salyut}}</ref> The DOS differed from the OPS modules in several aspects, including extra solar panels, front and (in Salyut 6 and 7) rear docking ports for [[Soyuz spacecraft]] and [[TKS spacecraft]], and finally more docking ports in DOS-7 and DOS-8 to attach further space station modules.

It was realized that the later civilian DOS stations could not only offer a cover story for the military Almaz programme, but could also be finished within one year and at least a year earlier than Almaz. The Salyut programme begun on 15 February 1970 on the condition that the crewed lunar program would not suffer.<ref name="Grahn"/> However, the engineers at OKB-1 perceived the [[LK (spacecraft)|L3 lunar lander]] effort as a dead-end and immediately switched to working on DOS.<ref name="EAsalyut"/>
In the end it turned out that the Soviet [[N1 (rocket)|N1 "Moon Shot" rocket]] never flew successfully, so OKB-1's decision to abandon the lunar program and derive a DOS space station from existing Soyuz subsystems and an Almaz/OPS hull proved to be right: The actual time from the DOS station's inception to the launch of the first DOS-based Salyut 1 space station took only 16 months; the world's first space station was launched by the Soviet Union, two years before the American [[Skylab]] or the first Almaz/OPS station flew.

Initially, the space stations were to be named ''Zarya'', the Russian word for 'Dawn'. However, as the launch of the first station in the programme was prepared, it was realised that this would conflict with the [[call sign]] ''Zarya'' of the [[Mission control center|flight control centre]] (TsUP) in [[Korolyov, Moscow Oblast|Korolyov]] – therefore the name of the space stations was changed to ''Salyut'' shortly before launch of ''Salyut 1''.<ref name="EAsalyut"/><ref>{{cite book |last=Payson |first=Dmitri |title=We’ll Build a Space Station for a Piece of Bread |date=June 1, 1993 |publisher=Rossiskiye Vesti |page=67 |edition=Translated in JPRS Report, Science & Technology, Central Eurasia: Space, June 28, 1993 (JPRSUSP-93-003)}}</ref> Another explanation given is that the name might have offended the Chinese, who purportedly were preparing a new rocket for launch, which they had already named "Dawn".<ref name="rockets_and_people">{{cite book |url=https://www.nasa.gov/connect/ebooks/rockets_people_vol4_detail.html |title=Rockets and People |volume=4 |publisher=National Aeronautics and Space Administration |series=NASA History Series |first=Boris E. |last=Chertok |editor-first=Asif A. |editor-last=Siddiqi |format=PDF |year=2011 |page=306 |isbn=978-0-16-089559-3 |id=SP-2011-4110}}</ref> The Salyut programme was managed by [[Kerim Kerimov]],<ref>{{cite book |url=https://books.google.com/books?id=V60oDwAAQBAJ&pg=PA85 |title=Outposts on the Frontier: A Fifty-Year History of Space Stations |publisher=[[University of Nebraska Press]] |first=Jay |last=Chladek |pages=85–86 |date=2017 |isbn=978-0-8032-2292-2}}</ref> chairman of the state commission for Soyuz missions.<ref>{{cite book |url=https://books.google.com/books?id=EbDGMiXvdG0C&pg=PA56 |title=Salyut - The First Space Station: Triumph and Tragedy |publisher=[[Springer Science+Business Media]] |first=Grujica S. |last=Ivanovich |page=56 |date=2008 |isbn=978-0-387-73585-6}}</ref>

A total of nine space stations were launched in the Salyut programme, with six successfully hosting crews and setting some records along the way. However, it was the stations Salyut 6 and Salyut 7 that became the workhorses of the program. Out of the total of 1,697 days of occupancy that all Salyut crews achieved, Salyut 6 and 7 accounted for 1,499. While Skylab already featured a second docking port, these two Salyut stations became the first that actually utilized two docking ports: This made it possible for two Soyuz spacecraft to dock at the same time for crew exchange of the station and for [[Progress spacecraft]] to resupply the station, allowing for the first time a continuous ("permanent") occupation of space stations.

The heritage of the Salyut programme continued to live on in the first multi-module space station ''[[Mir]]'' with the [[Mir Core Module]] ("DOS-7"), that accumulated 4,592 days of occupancy, and in the [[International Space Station]] (ISS) with the [[Zvezda (ISS module)|''Zvezda'' module]] ("DOS-8"), that {{as of|2012|8|21|lc=y}} accumulated 4,310 days of occupancy. Furthermore, the [[Functional Cargo Block]] space station modules were derived from the Almaz programme, with the ''[[Zarya]]'' ISS module being still in operation together with ''Zvezda''.<ref name="Ivanovich2008"/>

===First generation – The first space stations===



====Salyut 1 (DOS-1)====
{{Main|Salyut 1}}
'''Salyut 1 (DOS-1)''' ({{lang-ru|Салют-1}}; {{lang-en|Salute 1}}) was launched on 19 April 1971. It was the first space station to orbit the Earth.

Its first crew launched in [[Soyuz 10]] but were unable to board due to a failure in the docking mechanism; its second crew launched in [[Soyuz 11]] and remained on board for 23 productive days. The world's first successful crewed flight to a space station was however overshadowed when the crew was killed before the re-entry of Soyuz 11 on 30 June 1971. A pressure equalisation valve in the descent module of the Soyuz opened prematurely when the three modules of the spacecraft separated, suffocating all three.


Salyut 1 was moved to a higher orbit between July and August 1971 to ensure that it would not be destroyed prematurely through [[orbital decay]]. In the meantime, Soyuz capsules were being substantially re-designed to allow pressure suits to be worn during launch, docking maneuvers, and re-entry.<ref name="isbn0-387-30775-3">{{cite book |author=Baker, Philip |title=The Story of Manned Space Stations: an introduction |publisher=Springer |location=Berlin |year=2007 |page=[https://archive.org/details/storyofmannedspa0000bake/page/25 25] |isbn=0-387-30775-3 |url=https://archive.org/details/storyofmannedspa0000bake|url-access=registration |quote=The story of manned space stations: an introduction. }}</ref> However, Salyut 1 ran out of supplies before the Soyuz redesign effort was concluded, and it was decided to fire the engines for the last time on 11 October, to lower its orbit and ensure prompt destructive re-entry over the Pacific Ocean. After 175 days in space, the first real space station came to an end.<ref name="Ivanovich2008"/>
{{Clear}}

====DOS-2====
'''DOS-2''' was launched on 29 July 1972. It was similar in design to Salyut 1. The second stage of its [[Proton (rocket)|Proton rocket]] failed; DOS-2 never reached orbit and crashed into the Pacific Ocean. Just like the later DOS-3, DOS-2 was not given a Salyut name to conceal the failure from outside observers.

====Salyut 2 (OPS-1, military)====

{{Main|Salyut 2}}
'''Salyut 2 (OPS-1)''' ({{lang-ru|Салют-2}}; {{lang-en|Salute 2}}) was launched on 4 April 1973. The space station was, despite its "Salyut 2" designation, slated to be the first military space station, part of the highly classified [[Almaz]] military space station program – the Salyut designation was chosen to conceal its true nature. Although it launched successfully, within two days Salyut 2 began losing atmospheric pressure as its flight control system failed. The cause of the failure was likely shrapnel from the discarded and exploded Proton rocket upper stage that pierced the station. On 11 April 1973, seven days after launch, an unexplained accident caused both solar panels to be torn loose from the space station, cutting off all power. Salyut 2 re-entered on 28 May 1973.<ref name="Ivanovich2008"/>
{{Clear}}

====Kosmos 557 (DOS-3)====
[[File:Salyut 4 and Soyuz drawing.svg|thumb|The planned orbital configuration {{nowrap|of DOS-3.}}]]
{{Main|Kosmos 557}}
The module '''DOS-3''' was launched on 11 May 1973 – three days before the launch of [[Skylab]] – and was slated to become the next civilian space station with a Salyut designation. Due to errors in the flight control system while out of range from ground control, the station fired its orbital-correction engines until it consumed all of its fuel. Since the spacecraft was already in orbit and had been registered by Western radar, the Soviets disguised the launch as "[[Kosmos 557]]" – it was revealed to have been a Salyut station only much later. It re-entered Earth's atmosphere a week later, and burned up on re-entry.<ref name="Ivanovich2008"/>
{{Clear}}

====Salyut 3 (OPS-2, military)====
[[File:Almaz drawing.svg|thumb|OPS-2 ([[Salyut 3]])]]
{{Main|Salyut 3}}
'''Salyut 3 (OPS-2)''' ({{lang-ru|Салют-3}}; {{lang-en|Salute 3}}) was launched on 25 June 1974. Like Salyut 2, it was another Almaz military space station, although unlike its predecessor, it was launched successfully. It was used to test a wide variety of reconnaissance sensors, returning a canister of film for analysis. On 24 January 1975, after the station had been ordered to deorbit, trials of an on-board autocannon (either a [[Nudelman-Rikhter NR-23|23 mm Nudelman aircraft cannon]] or its [[Nudelman-Rikhter NR-30|30 mm]] counterpart) were conducted with positive results at ranges from 3000 m to 500 m.<ref>[http://space.au.af.mil/books/oberg/ch02.pdf James Olberg, ''Space Power Theory'', Ch. 2]</ref> Cosmonauts have confirmed that a target satellite was destroyed in the test.{{citation needed|date=January 2014}} The next day, the station was ordered to deorbit. Only one of the two intended crews successfully boarded and crewed the station, brought by [[Soyuz 14]]; [[Soyuz 15]] attempted to bring a second crew but failed to dock. Nevertheless, it was an overall success. The station's orbit decayed, and it re-entered the atmosphere on 24 January 1975.<ref name="Ivanovich2008"/>
{{Clear}}

====Salyut 4 (DOS-4)====
[[File:Salyut-4 diagram.gif|thumb|DOS-4 ([[Salyut 4]])]]
{{Main|Salyut 4}}
'''Salyut 4 (DOS-4)''' ({{lang-ru|Салют-4}}; {{lang-en|Salute 4}}) was launched on 26 December 1974. It was essentially a copy of DOS-3, but was a complete success. Two crews made stays aboard Salyut 4 ([[Soyuz 17]] and [[Soyuz 18]]), including one of 63 days duration. An uncrewed Soyuz capsule ([[Soyuz 20]]) remained docked to the station for three months, proving the system's long-term durability. Salyut 4 was deorbited on 2 February 1977, and re-entered the Earth's atmosphere the next day.<ref name="Ivanovich2008"/>
{{Clear}}

====Salyut 5 (OPS-3, military)====
{{Main|Salyut 5}}
'''Salyut 5 (OPS-3)''' ({{lang-ru|Салют-5}}; [[English language|English]] translation ''Salute 5'') was launched on 22 June 1976. It was the third and last Almaz military space station. Its launch and subsequent mission were both completed successfully, with three crews launching and two ([[Soyuz 21]] and [[Soyuz 24]]) successfully boarding the craft for lengthy stays (the second crew on [[Soyuz 23]] was unable to dock and had to abort). Salyut 5 reentered on 8 August 1977.

Following Salyut 5, the Soviet military decided that with the advent of more sophisticated [[spy satellite]]s, the tactical advantages were not worth the expense of the program and withdrew from the program. The focuses for the last two Salyut stations shifted towards civilian research and prestige for the Soviet Union.<ref name="FurnissDavid2007">{{cite book|author1=Tim Furniss|author2=Shayler David|author3=Michael D. Shayler|title=Praxis Manned Spaceflight Log 1961-2006|url=https://books.google.com/books?id=YbYDn1Spf9oC&pg=PA198|date=17 August 2007|publisher=Springer Science & Business Media|isbn=978-0-387-73980-9|pages=198–}}</ref>
{{Clear}}

===Second generation – Long-duration inhabitation of space===
In 1977 another marked step forward was made with the second generation of Salyut stations. The aim was to continuously occupy a space station with long-duration expeditions, for the first time in spaceflight.

Although Salyut 6 and Salyut 7 resembled the previous Salyut stations in overall design, several revolutionary changes were made to the stations and program for the aim of continuous occupation. The new stations featured a longer design life and a second [[Spacecraft docking|docking port]] at the aft of the stations – crew exchanges and station "handovers" were now made possible by docking two crewed Soyuz spacecraft at the same time. Furthermore, the uncrewed [[Progress (spacecraft)|Progress resupply craft]] was created based on the crewed Soyuz, to resupply the crew and station with air, air regenerators, water, food, clothing, bedding, mail, propellants, pressurant, and other supplies. While the Progress docked to the station's second docking port, the crew's Soyuz spacecraft could remain docked to the station's first port. The Progress spacecraft even delivered hardware for updating onboard experiments and permitting repairs to the station, extending its life.<ref name=Mir>{{cite web |url=http://ston.jsc.nasa.gov/collections/TRS/_techrep/RP1357.pdf |title=Mir Hardware Heritage |last=Portree |first=David |date=March 1995 |publisher=NASA |access-date=24 August 2012 |url-status=dead |archive-url=https://web.archive.org/web/20090907191412/http://ston.jsc.nasa.gov/collections/TRS/_techrep/RP1357.pdf |archive-date=7 September 2009 |df= }}</ref>

====Salyut 6 (DOS-5)====
[[File:Salyut 6.jpg|thumb|DOS-5 ([[Salyut 6]]) space station with two docked spacecraft]]
{{Main|Salyut 6}}
'''Salyut 6 (DOS-5)''' ({{lang-ru|Салют-6}}; {{lang-en|Salute 6}}) was launched on 29 September 1977. Salyut 6 was crewed between 1977 and 1981 by [[List of human spaceflights to Salyut space stations#Salyut 6|16 spacecraft]], bringing [[List of Salyut expeditions#Salyut 6|five long-duration crews]] ("expeditions") and 11 short-term crews. The very first long-duration crew on Salyut 6 broke a record set onboard Skylab, staying 96 days in orbit. The short-term crews included foreign cosmonauts from the [[Interkosmos]] programme setting several firsts: the first citizen in space of a nation other than the [[United States]] or the [[Soviet Union]], the [[Arnaldo Tamayo Méndez|first black and Hispanic person in space]] and the [[Phạm Tuân|first Asian person in space]]. The longest flight onboard Salyut 6 lasted 185 days. The [[Soyuz 32|third long-duration Salyut 6 crew]] deployed a 10-meter radio-telescope antenna delivered by an uncrewed cargo spacecraft.

After Salyut 6 crewed operations were discontinued in 1981, a heavy uncrewed spacecraft called [[TKS spacecraft|TKS]], developed using hardware left from the canceled Almaz programme, was docked to the station as a hardware test. Some unconfirmed reports say that the station was functionally capable of even more missions, but combating the ever-increasing mold in living quarters was becoming impossible, and in practice caused the retirement decision. Salyut 6 was deorbited on 29 July 1982.<ref>{{cite book|title=Jane's Spaceflight Directory|url=https://books.google.com/books?id=jLdTAAAAMAAJ|year=1986|publisher=Jane's|isbn=978-0-7106-0367-8}}</ref>
{{Clear}}

====Salyut 7 (DOS-6)====
[[File:Model of Salyut-7 with two Soyuz spacecrafts.JPEG|thumb|A full-scale model of a [[Salyut 7]] space station and two docked spacecraft. On the left a Soyuz model can be seen docked to the front port, and on the right a Progress model is docked at the aft end. The display is in front of one of the pavilions of the [[Exhibition of Soviet National Economic Achievement]].]]
{{Main|Salyut 7}}
'''Salyut 7 (DOS-6)''' ({{lang-ru|Салют-7}}; {{lang-en|Salute 7}}) was launched on 19 April 1982. DOS-6 was built as the backup vehicle for Salyut 6 with very similar equipment and capabilities, though several more advanced features were included. The station was in orbit for eight years and ten months, during which time it was crewed by [[List of human spaceflights to Salyut space stations#Salyut 7|ten spacecraft]] bringing [[List of Salyut expeditions#Salyut 7|six long-duration crews]] ("expeditions") and 4 short-term crews (including French and Indian cosmonauts in the [[Interkosmos]] programme).

On 12 February 1985, during an uncrewed period, contact with Salyut 7 was lost. The station had become crippled by electrical problems, with all systems shut down and the station beginning to drift. It was decided to put together a salvage mission, and on June 1985 the [[Soyuz T-13]] mission, in what was in the words of author David S. F. Portree "one of the most impressive feats of in-space repairs in history," managed to bring the station online again.<ref name=Mir/>

The [[Soyuz T-15]] mission was the last to visit Salyut 7 in 1986, ferrying equipment from Salyut 7 to the new ''[[Mir]]'' space station; This was so far the only ferry flight between two space stations.

Aside from the many experiments and observations made on Salyut 7, the station also tested the docking and use of large modules with an orbiting space station. These modules, called "Heavy Cosmos modules", helped engineers develop technology necessary to build ''Mir''.{{citation_needed|date=August 2019}}

Salyut 7 was deorbited on 7 February 1991.<ref name="Ivanovich2008"/>
{{Clear}}

===Salyut's heritage – Modular space stations===
After the second generation, plans for the next generation of Salyut stations called for the cores '''DOS-7''' and '''DOS-8''' to allow, for the first time in spaceflight, the addition of several modules to a station core and to create a modular space station.{{Citation needed|date=August 2012}}
For this, the DOS modules were to be equipped with a total of four docking ports: one docking port at the aft of the station as in the second generation Salyuts, and the replacement of the front docking port with a "docking sphere" containing a front port and starboard docking port.{{Citation needed|date=August 2012}}

While the station cores DOS-7 and DOS-8 were built and flown, they never received the Salyut designation. Instead, DOS-7 evolved into the [[Mir Core Module]] for the ''Mir'' space station that followed the Salyut programme, and DOS-8 was used as the [[Zvezda (ISS module)|''Zvezda'' Service Module]] for the [[International Space Station]] (ISS) which followed ''Mir''.

The heritage from the Almaz program is present even today. While the last space station from the Almaz programme was flown as Salyut 5 in 1976, the development of the Almaz [[TKS spacecraft]] evolved into the [[Functional Cargo Block]], which formed the basis for several ''Mir'' modules, the experimental [[Polyus (spacecraft)|Polyus orbital weapons platform]] and the [[Zarya (ISS module)|''Zarya'']] module of the ISS.{{Citation needed|date=August 2012}}<ref name="Ivanovich2008"/>

====Mir Core Module (DOS-7)====
[[File:Mir base block drawing.png|thumb|DOS-7 (Mir Core Module)]]
{{Main|Mir Core Module|Functional Cargo Block|Mir}}
'''DOS-7''' continued to be developed during Salyut 7, becoming the Mir Core Module of the ''[[Mir]]'' space station – the first modular space station, with crewed operations lasting from 1986 to 2000.

The station featured upgraded computers and solar arrays, and accommodations for two cosmonauts each having their own cabin. A total of six docking ports were available on the Mir Core Module, which were used for space station modules and visiting spacecraft – the docking sphere design had been upgraded from its initial Salyut design to contain a maximum of five docking ports (front, port, starboard, zenith and nadir). And finally, the modules for ''Mir'' were derived from the Functional Cargo Block design of the Almaz programme.

The name of the ''Mir'' space station – {{lang-ru|Мир}}, literally ''Peace'' or ''World'' – was to signify the intentions of the Soviet Union to bring peace to the world. However, it was during the time of ''Mir'' that the [[Dissolution of the Soviet Union|Soviet Union was dissolved]] in 1991, ending what was begun with the 1917 [[October Revolution]] in Russia.
This dissolution had started with the Soviet "[[perestroika]] and [[glasnost]]" ("restructuring and openness") reform campaigns by Soviet leader [[Mikhail Gorbachev]] in the 1980s, had reached a preliminary endpoint with the [[revolutions of 1989]] and the end of the communist [[Eastern Bloc]] ([[Warsaw Pact]] and the [[Council for Mutual Economic Assistance|CoMEcon]]), finally to reach the Soviet Union itself in 1991.<ref name="Ivanovich2008"/>

While the [[Russia|Russian Federation]] became the successor to much of the dissolved Soviet Union and was in a position to continue the [[Soviet space program]] with the [[Russian Federal Space Agency]], it faced severe difficulties: imports and exports had steeply declined as the economic exchange with CoMEcon nations had crumbled away, leaving the industry of the former Soviet Union in shambles. Not only did the political change in eastern Europe signify an end of contributions to the space program by eastern European nations (such as the [[East German]] [[Carl Zeiss AG|Carl Zeiss Jena]]), but parts of the Soviet space industry were located in the newly independent [[Ukraine]], which was similarly cash-strapped as Russia and started to demand [[hard currency]] for its contributions.

It was during this time of transition and upheaval that the [[Shuttle–Mir Program]] was established between the Russian Federation and the [[United States]] in 1993. The former adversaries would now cooperate, with "Phase One" consisting of joint missions and flights of the US [[Space Shuttle]] to the Mir space station. It was a partnership with stark contrasts – Russia needed an inflow of hard currency to keep their space program aloft, while in the US it was seen as a chance to learn from the over 20 years of experience of Soviet space station operations. It was "Phase Two" of this Shuttle-Mir Program that would lead to the [[International Space Station]].<ref name="Shayler2004">{{cite book|author=David Shayler|title=Walking in Space|url=https://books.google.com/books?id=g8PW0_WNTDsC&pg=PA291|date=3 June 2004|publisher=Springer Science & Business Media|isbn=978-1-85233-710-0|pages=291–}}</ref>

{{Clear}}


====Zvezda ISS Service Module (DOS-8)====
[[File:ISS Zvezda module-small.jpg|thumb|DOS-8 ([[Zvezda (ISS module)|Zvezda]] ISS module).]]
{{Main|Zvezda (ISS module)|Zarya|Functional Cargo Block|ISS}}
'''DOS-8''' evolved into the [[Mir-2]] project, intended to replace ''Mir''. Finally, it became the International Space Station (ISS) [[Zvezda (ISS module)|''Zvezda'' Service Module]] and formed the core of the early ISS together with the ''Zarya'' module (which was derived from Almaz Functional Cargo Block designs).
{{Clear}}


==Data table==

The first generation of Salyut stations received few craft for rendezvous and docking. By contrast the programme's second generation stations, Salyut 6 and Salyut 7, received multiple crewed and uncrewed craft for rendezvous, docking attempts (whether successful or not), human habitation, crew transfer, and supply. The table counts craft which achieved rendezvous with their targets as visiting craft, regardless of whether they docked successfully.

{| class="wikitable" 
|- style="background:#efefef;"
! style="text-align:center;"|Space Station
! style="text-align:center;"|Core module
! style="text-align:center;"|Launched
! style="text-align:center;"|Reentered
! style="text-align:center;"|Days in orbit
! style="text-align:center;"|Days occupied
! style="text-align:center;"|[[List of Salyut visitors|All crew and visitors]] (total)
! style="text-align:center;"|[[List of human spaceflights to Salyut space stations|Visiting crewed spacecraft]]
! style="text-align:center;"|[[List of uncrewed spaceflights to Salyut space stations|Visiting uncrewed spacecraft]]
! style="text-align:center;"|Mass kg
|-
| style="text-align:center;"| ''''' [[Salyut 1]] '''''
|| DOS-1
||19 April 1971 01:40:00 UTC
||11 October 1971  
|align="right"|{{time interval|19 April 1971 01:40|11 October 1971|show=d|disp=raw|duration=on}}
|align="right"|23
|align="right"|3
|align="right"|2
|align="right"|-
|align="right"|18,500
|-
| style="text-align:center;"| -
|| [[DOS-2]]
||29 July 1972
||29 July 1972
|align="right"|-
|align="right"|-
|align="right"|-
|align="right"|-
|align="right"|-
|align="right"|18,000
|-
| style="text-align:center;"| ''''' [[Salyut 2]] '''''
|| OPS-1 (military)
||4 April 1973 09:00:00 UTC
||28 May 1973  
|align="right"|{{time interval|4 April 1973 09:00|28 May 1973|show=d|disp=raw|duration=on}}
|align="right"|-
|align="right"|-
|align="right"|-
|align="right"|-
|align="right"|18,500
|-
| style="text-align:center;"| - ('''[[Kosmos 557]]''')
|| DOS-3
||11 May 1973 00:20:00 UTC
||22 May 1973  
|align="right"|{{time interval|11 May 1973 00:20|22 May 1973|show=d|disp=raw|duration=on}}
|align="right"|-
|align="right"|-
|align="right"|-
|align="right"|-
|align="right"|19,400
|-
| style="text-align:center;"| ''''' [[Salyut 3]] '''''
|| OPS-2 (military)
||25 June 1974 22:38:00 UTC
||24 January 1975  
|align="right"|{{time interval|25 June 1974 22:38|24 January 1975|show=d|disp=raw|duration=on}}
|align="right"|15
|align="right"|2
|align="right"|2
|align="right"|-
|align="right"|18,500
|-
| style="text-align:center;"| ''''' [[Salyut 4]] '''''
|| DOS-4
||26 December 1974 04:15:00 UTC
||3 February 1977  
|align="right"|{{time interval|26 December 1974 04:15|3 February 1977|show=d|disp=raw|duration=on}}
|align="right"|92
|align="right"|4
|align="right"|2
|align="right"|1
|align="right"|18,500
|-
| style="text-align:center;"| ''''' [[Salyut 5]] '''''
|| OPS-3 (military)
||22 June 1976 18:04:00 UTC
||8 August 1977  
|align="right"|{{time interval|22 June 1976 18:04|8 August 1977|show=d|disp=raw|duration=on}}
|align="right"|67
|align="right"|4
|align="right"|3
|align="right"|-
|align="right"|19,000
|-
| style="text-align:center;"| ''''' [[Salyut 6]] '''''
|| DOS-5
||29 September 1977 06:50:00 UTC
||29 July 1982  
|align="right"|{{time interval|29 September 1977 06:50|29 July 1982|show=d|disp=raw|duration=on}}
|align="right"|683
|align="right"|33
|align="right"|18
|align="right"|15
|align="right"|19,824
|-
| style="text-align:center;"| ''''' [[Salyut 7]] '''''
|| DOS-5-2
||19 April 1982 19:45:00 UTC
||7 February 1991  
|align="right"|{{time interval|19 April 1982 19:45|7 February 1991|show=d|disp=raw|duration=on}}
|align="right"|816
|align="right"|26
|align="right"|11
|align="right"|15
|align="right"|18,900

|-
|colspan="10"| For comparison, the DOS-7 and DOS-8 modules that were derived from the Salyut programme:

|-
| style="text-align:center;"| '''''[[Mir]]'''''
|| DOS-7 [[Mir Core Module]]
||19 February 1986 
||23 March 2001 
|align="right"|{{time interval|19 February 1986 21:28|23 March 2001 05:59|show=d|disp=raw|duration=on}}
|align="right"|4,592
|align="right"|104
|align="right"|39
|align="right"|64
|align="right"|20,400

|-
| style="text-align:center;"| '''[[International Space Station|ISS]]'''
|| DOS-8 [[Zvezda (ISS module)|''Zvezda'']] ISS Service Module
||12 July 2000 
||Still in orbit
|align="right"|{{time interval|12 July 2000|show=d|disp=raw|duration=on}}
|align="right"|6,392
|align="right"|205
|align="right"|77 {{nowrap|([[Russian Orbital Segment|ROS]] and [[US Orbital Segment|USOS]])}}
|align="right"|59 {{nowrap|([[Russian Orbital Segment|ROS]] and [[US Orbital Segment|USOS]])}}
|align="right"|19,051
|}

All data for ''Zvezda'' (DOS-8) {{as of|2018|5|6|lc=y}}.

==See also==
{{Portal|Soviet Union|Spaceflight}}
* [[List of human spaceflights to Salyut space stations]]
* [[List of Salyut expeditions]]
* [[List of Salyut visitors]]
* [[List of Salyut spacewalks]]
* [[List of uncrewed spaceflights to Salyut space stations]]

==References==
{{Reflist|2}}

==External links==
{{Commons category|Salyut}}
* {{cite book |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870012563.pdf |title=Soviet Space Stations as Analogs |publisher=California State University |edition=2nd |first1=B. J. |last1=Bluth |first2=Martha |last2=Helppie |date=August 1986 |id=NASA CR-180920; N87-21996}}
* {{cite book |url=http://ston.jsc.nasa.gov/collections/TRS/_techrep/RP1357.pdf |title=Mir Hardware Heritage |publisher=NASA |first=David S. F. |last=Portree |date=March 1995 |id=NASA RP-1357 |url-status=dead |archive-url=https://web.archive.org/web/20030419063111/http://ston.jsc.nasa.gov/collections/TRS/_techrep/RP1357.pdf |archive-date=2003-04-19 |df= }}
* [http://www.zarya.info/Diaries/StationsDOS/Salyut1.php "Diaries of the Salyut missions"] at Zarya.info
* [https://www.wired.com/2012/03/skylab-salyut-space-laboratory-1972/ "Skylab-Salyut Space Laboratory (1972)"] at ''Wired.com''

{{Salyut Program}}
{{Almaz Program}}
{{Space stations}}
{{Crewed spacecraft}}
{{Russian space program}}
{{Spaceflight lists and timelines}}

{{DEFAULTSORT:Salyut Program}}
[[Category:1971 in spaceflight]]
[[Category:1973 in spaceflight]]
[[Category:Salyut program| ]]
[[Category:Space stations]]

OmegA

2019-11-21T20:55:08Z

Blastr42: /* Multiple configurations */

{{short description|US launch vehicle}}
{{redirect|OmegA|other uses|omega (disambiguation)}}
{{Infobox rocket
| name = Omega
| logo = Omega logo.svg
| logo_alt = Logo of OmegA
| image = OmegA rocket.jpeg
| caption =
| manufacturer = [[Northrop Grumman]]
| country-origin = [[United States]]
| height = {{convert|59.84|m|ft|sp=us}}
| diameter = {{convert|3.71|m|ft|sp=us}} first stage {{convert|5.25|m|ft|sp=us}} upper stage
| mass =
| stages = 3
| capacities =
{{Infobox rocket/payload
| location = [[Geostationary transfer orbit|GTO]]
| kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="omega-factsheet">{{cite web |url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf |title=OmegA Factsheet |publisher=[[Northrop Grumman]] |accessdate=24 October 2019}}</ref>
}}
{{Infobox rocket/payload
| location = [[Geostationary orbit|GEO]]
| kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="omega-factsheet" />
}}
| family = [[Shuttle-Derived Launch Vehicle]]
| derivatives = 
| comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
| status = Under development
| sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]]
| launches = 0
| success =
| fail =
| partial =
| first = 2021 (projected)<ref name="omega-factsheet" />
| stagedata =
{{Infobox rocket/stage
| type = booster
| diff = 
| stageno = 
| name = [[Graphite-Epoxy Motor|GEM-63XLT]]
| number = 2 to 6
| diameter = {{convert|63|in|m|order=flip|sp=us|abbr=on}}
| solid = yes
| total = 
| SI = {{convert|279.3|isp}}
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = First
| engines = [[Castor (rocket stage)|Castor]] 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| solid = yes
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Second
| engines = [[Castor (rocket stage)|Castor]] 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Third
| engines = 2 × [[RL10|RL-10C-5-1]]
| thrust = {{convert|22890|lbf|kN|order=flip}}
| SI = ~450 seconds (vacuum)
| burntime =
| fuel = [[LOX]]/[[LH2]]
}}
}}

'''Omega''', stylized as "'''OmegA'''", is a [[launch vehicle]] in development by [[Northrop Grumman]] as an [[National Security Space Launch|NSSL]] replacement program intended for national security and commercial satellites.<ref name=":0">{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have used a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne]]<ref name="SpaceNews-20180416">{{cite news |last1=Erwin |first1=Sandra |last2=Berger |first2=Brian |url=https://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/ |title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket |work=[[SpaceNews]] |date=16 April 2018 |access-date=18 April 2018 |language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spacenews.com/northrop-grumman-to-launch-omega-rocket-from-ulas-delta-4-pad-at-vandenberg/|title=Northrop Grumman to launch OmegA rocket from ULA’s Delta 4 pad at Vandenberg|last=Erwin|first=Sandra|date=26 October 2019|website=|publisher=Spaceflight Now|url-status=live|archive-url=|archive-date=|access-date=}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development was to start once the Air Force reached a funding decision. In October 2018, the Air Force announced that Northrop Grumman was awarded $792 million for initial development of the Omega launch vehicle.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

==History==
[[File:Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, [[Orbital ATK]] (now [[Northrop Grumman Innovation Systems]]) was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine for US national security payloads.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5–6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher took place in early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{failed verification|date=August 2019}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). The rocket would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor. The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}} and has a TLI capability of up to 12,300 kg (27,000 lb).<ref name="omega-factsheet" /><ref name="SpaceNews-20180416" />

In October 2018, Omega was awarded a Launch Services Agreement worth $791,601,015 to design, build and launch the first Omega rockets.<ref name=SpaceNews-20181010>{{cite web|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force Awards Launch Vehicle Development Contracts to Blue Origin Northrop Grummand ULA|publisher=Space News|date=10 October 2018 |author=Sandra Erwin}}</ref>

In late May 2019, while conducting a static fire test of the first stage SRB, an anomaly occurred resulting in the destruction of the SRB nozzle (but not the stage itself).<ref name=SFloridaToday-20190530>{{cite web|url=https://www.floridatoday.com/story/tech/science/space/2019/05/30/live-watch-northrop-grumman-test-fire-its-omega-rocket-first-stage-in-utah/1289351001/|title=Anomaly after Northrop Grumman successfully test fires Omega rocket in Utah|publisher=Florida Today|date=30 May 2019 |author=Emre Kelly}}</ref>

In 2019, NGIS bid the Omega launch vehicle to the US Air Force for the multi-year block buy launch contract that would cover all US national security launches in 2022–2026.<ref name=ars20190812>{{cite news |last=Berger|first=Eric |url=https://arstechnica.com/science/2019/08/four-rocket-companies-are-competing-for-air-force-funding-and-it-is-war/ |title=Four rocket companies are competing for Air Force funding, and it is war |work=[[Ars Technica]] |date=12 August 2019 |accessdate=21 August 2019 |quote=''The bet by Northrop is that the US military, through its national security launch contract, would want to support one of the nation's most critical suppliers of solid-rocket motors for intercontinental ballistic missiles. Northrop officials have not said whether they would continue development of the Omega rocket if Northrop were to lose out on the Air Force contract.''}}</ref>

==Multiple configurations==
The rocket will have two basic configurations, an intermediate and a heavy launch. Both configurations would have a minimum of 2 thrust vectoring GEM-63XLTs for roll control. The intermediate version will have a two segment, [[Shuttle-Derived Launch Vehicle|shuttle-derived launch vehicle]] (SDLV) 2-segment [[solid rocket booster]] (SRB) first stage, a single segment SRB second stage, and a liquid hydrogen fuelled third stage. The heavy configuration will have a 4-segment SRB first stage, and the same upper stages.<ref>{{Cite web|url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf|title=OmegA Factsheet|last=|first=|date=|website=Northrop Grumman|url-status=live|archive-url=|archive-date=|access-date=}}</ref> Additional versions are projected to add additional SRBs as side boosters. The [[Shuttle-Derived Launch Vehicle|SDLV]] SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }}</ref>

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

==References==
{{Reflist|2}}

==External links==
*[http://www.northropgrumman.com/Capabilities/Omega/Pages/default.aspx OmegA official web site]

{{S-start}}
{{Succession box
| title = Single-stick SRB-based [[Shuttle-Derived Launch Vehicle|SDLV]]
| years = 2016–
| before = [[Liberty (rocket)|Liberty]]
| after = Incumbent
}}
{{S-end}}

{{US launch systems}}
{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

OmegA

2019-11-21T20:52:59Z

Blastr42: /* History */

{{short description|US launch vehicle}}
{{redirect|OmegA|other uses|omega (disambiguation)}}
{{Infobox rocket
| name = Omega
| logo = Omega logo.svg
| logo_alt = Logo of OmegA
| image = OmegA rocket.jpeg
| caption =
| manufacturer = [[Northrop Grumman]]
| country-origin = [[United States]]
| height = {{convert|59.84|m|ft|sp=us}}
| diameter = {{convert|3.71|m|ft|sp=us}} first stage {{convert|5.25|m|ft|sp=us}} upper stage
| mass =
| stages = 3
| capacities =
{{Infobox rocket/payload
| location = [[Geostationary transfer orbit|GTO]]
| kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="omega-factsheet">{{cite web |url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf |title=OmegA Factsheet |publisher=[[Northrop Grumman]] |accessdate=24 October 2019}}</ref>
}}
{{Infobox rocket/payload
| location = [[Geostationary orbit|GEO]]
| kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="omega-factsheet" />
}}
| family = [[Shuttle-Derived Launch Vehicle]]
| derivatives = 
| comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
| status = Under development
| sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]]
| launches = 0
| success =
| fail =
| partial =
| first = 2021 (projected)<ref name="omega-factsheet" />
| stagedata =
{{Infobox rocket/stage
| type = booster
| diff = 
| stageno = 
| name = [[Graphite-Epoxy Motor|GEM-63XLT]]
| number = 2 to 6
| diameter = {{convert|63|in|m|order=flip|sp=us|abbr=on}}
| solid = yes
| total = 
| SI = {{convert|279.3|isp}}
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = First
| engines = [[Castor (rocket stage)|Castor]] 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| solid = yes
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Second
| engines = [[Castor (rocket stage)|Castor]] 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Third
| engines = 2 × [[RL10|RL-10C-5-1]]
| thrust = {{convert|22890|lbf|kN|order=flip}}
| SI = ~450 seconds (vacuum)
| burntime =
| fuel = [[LOX]]/[[LH2]]
}}
}}

'''Omega''', stylized as "'''OmegA'''", is a [[launch vehicle]] in development by [[Northrop Grumman]] as an [[National Security Space Launch|NSSL]] replacement program intended for national security and commercial satellites.<ref name=":0">{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have used a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne]]<ref name="SpaceNews-20180416">{{cite news |last1=Erwin |first1=Sandra |last2=Berger |first2=Brian |url=https://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/ |title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket |work=[[SpaceNews]] |date=16 April 2018 |access-date=18 April 2018 |language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spacenews.com/northrop-grumman-to-launch-omega-rocket-from-ulas-delta-4-pad-at-vandenberg/|title=Northrop Grumman to launch OmegA rocket from ULA’s Delta 4 pad at Vandenberg|last=Erwin|first=Sandra|date=26 October 2019|website=|publisher=Spaceflight Now|url-status=live|archive-url=|archive-date=|access-date=}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development was to start once the Air Force reached a funding decision. In October 2018, the Air Force announced that Northrop Grumman was awarded $792 million for initial development of the Omega launch vehicle.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

==History==
[[File:Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, [[Orbital ATK]] (now [[Northrop Grumman Innovation Systems]]) was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine for US national security payloads.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5–6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher took place in early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{failed verification|date=August 2019}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). The rocket would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor. The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}} and has a TLI capability of up to 12,300 kg (27,000 lb).<ref name="omega-factsheet" /><ref name="SpaceNews-20180416" />

In October 2018, Omega was awarded a Launch Services Agreement worth $791,601,015 to design, build and launch the first Omega rockets.<ref name=SpaceNews-20181010>{{cite web|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force Awards Launch Vehicle Development Contracts to Blue Origin Northrop Grummand ULA|publisher=Space News|date=10 October 2018 |author=Sandra Erwin}}</ref>

In late May 2019, while conducting a static fire test of the first stage SRB, an anomaly occurred resulting in the destruction of the SRB nozzle (but not the stage itself).<ref name=SFloridaToday-20190530>{{cite web|url=https://www.floridatoday.com/story/tech/science/space/2019/05/30/live-watch-northrop-grumman-test-fire-its-omega-rocket-first-stage-in-utah/1289351001/|title=Anomaly after Northrop Grumman successfully test fires Omega rocket in Utah|publisher=Florida Today|date=30 May 2019 |author=Emre Kelly}}</ref>

In 2019, NGIS bid the Omega launch vehicle to the US Air Force for the multi-year block buy launch contract that would cover all US national security launches in 2022–2026.<ref name=ars20190812>{{cite news |last=Berger|first=Eric |url=https://arstechnica.com/science/2019/08/four-rocket-companies-are-competing-for-air-force-funding-and-it-is-war/ |title=Four rocket companies are competing for Air Force funding, and it is war |work=[[Ars Technica]] |date=12 August 2019 |accessdate=21 August 2019 |quote=''The bet by Northrop is that the US military, through its national security launch contract, would want to support one of the nation's most critical suppliers of solid-rocket motors for intercontinental ballistic missiles. Northrop officials have not said whether they would continue development of the Omega rocket if Northrop were to lose out on the Air Force contract.''}}</ref>

==Multiple configurations==
The rocket will have two basic configurations, an intermediate and a heavy launch. The intermediate version will have a two segment, [[Shuttle-Derived Launch Vehicle|shuttle-derived launch vehicle]] (SDLV) 2-segment [[solid rocket booster]] (SRB) first stage, a single segment SRB second stage, and a liquid hydrogen fuelled third stage. The heavy configuration will have a 4-segment SRB first stage, and the same upper stages.<ref>{{Cite web|url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf|title=OmegA Factsheet|last=|first=|date=|website=Northrop Grumman|url-status=live|archive-url=|archive-date=|access-date=}}</ref> Additional versions are projected to add additional SRBs as side boosters. The [[Shuttle-Derived Launch Vehicle|SDLV]] SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }}</ref>

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

==References==
{{Reflist|2}}

==External links==
*[http://www.northropgrumman.com/Capabilities/Omega/Pages/default.aspx OmegA official web site]

{{S-start}}
{{Succession box
| title = Single-stick SRB-based [[Shuttle-Derived Launch Vehicle|SDLV]]
| years = 2016–
| before = [[Liberty (rocket)|Liberty]]
| after = Incumbent
}}
{{S-end}}

{{US launch systems}}
{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

OmegA

2019-11-21T20:52:06Z

Blastr42:

{{short description|US launch vehicle}}
{{redirect|OmegA|other uses|omega (disambiguation)}}
{{Infobox rocket
| name = Omega
| logo = Omega logo.svg
| logo_alt = Logo of OmegA
| image = OmegA rocket.jpeg
| caption =
| manufacturer = [[Northrop Grumman]]
| country-origin = [[United States]]
| height = {{convert|59.84|m|ft|sp=us}}
| diameter = {{convert|3.71|m|ft|sp=us}} first stage {{convert|5.25|m|ft|sp=us}} upper stage
| mass =
| stages = 3
| capacities =
{{Infobox rocket/payload
| location = [[Geostationary transfer orbit|GTO]]
| kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="omega-factsheet">{{cite web |url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf |title=OmegA Factsheet |publisher=[[Northrop Grumman]] |accessdate=24 October 2019}}</ref>
}}
{{Infobox rocket/payload
| location = [[Geostationary orbit|GEO]]
| kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="omega-factsheet" />
}}
| family = [[Shuttle-Derived Launch Vehicle]]
| derivatives = 
| comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
| status = Under development
| sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]]
| launches = 0
| success =
| fail =
| partial =
| first = 2021 (projected)<ref name="omega-factsheet" />
| stagedata =
{{Infobox rocket/stage
| type = booster
| diff = 
| stageno = 
| name = [[Graphite-Epoxy Motor|GEM-63XLT]]
| number = 2 to 6
| diameter = {{convert|63|in|m|order=flip|sp=us|abbr=on}}
| solid = yes
| total = 
| SI = {{convert|279.3|isp}}
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = First
| engines = [[Castor (rocket stage)|Castor]] 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| solid = yes
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Second
| engines = [[Castor (rocket stage)|Castor]] 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Third
| engines = 2 × [[RL10|RL-10C-5-1]]
| thrust = {{convert|22890|lbf|kN|order=flip}}
| SI = ~450 seconds (vacuum)
| burntime =
| fuel = [[LOX]]/[[LH2]]
}}
}}

'''Omega''', stylized as "'''OmegA'''", is a [[launch vehicle]] in development by [[Northrop Grumman]] as an [[National Security Space Launch|NSSL]] replacement program intended for national security and commercial satellites.<ref name=":0">{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have used a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne]]<ref name="SpaceNews-20180416">{{cite news |last1=Erwin |first1=Sandra |last2=Berger |first2=Brian |url=https://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/ |title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket |work=[[SpaceNews]] |date=16 April 2018 |access-date=18 April 2018 |language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spacenews.com/northrop-grumman-to-launch-omega-rocket-from-ulas-delta-4-pad-at-vandenberg/|title=Northrop Grumman to launch OmegA rocket from ULA’s Delta 4 pad at Vandenberg|last=Erwin|first=Sandra|date=26 October 2019|website=|publisher=Spaceflight Now|url-status=live|archive-url=|archive-date=|access-date=}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development was to start once the Air Force reached a funding decision. In October 2018, the Air Force announced that Northrop Grumman was awarded $792 million for initial development of the Omega launch vehicle.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

==History==
[[File:Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, [[Orbital ATK]] (now [[Northrop Grumman Innovation Systems]]) was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine for US national security payloads.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5–6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher took place in early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{failed verification|date=August 2019}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). The rocket would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor. The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}} and a TLI payload up to 12,300 kg (27,000 lb).<ref name="omega-factsheet" /><ref name="SpaceNews-20180416" />

In October 2018, Omega was awarded a Launch Services Agreement worth $791,601,015 to design, build and launch the first Omega rockets.<ref name=SpaceNews-20181010>{{cite web|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force Awards Launch Vehicle Development Contracts to Blue Origin Northrop Grummand ULA|publisher=Space News|date=10 October 2018 |author=Sandra Erwin}}</ref>

In late May 2019, while conducting a static fire test of the first stage SRB, an anomaly occurred resulting in the destruction of the SRB nozzle (but not the stage itself).<ref name=SFloridaToday-20190530>{{cite web|url=https://www.floridatoday.com/story/tech/science/space/2019/05/30/live-watch-northrop-grumman-test-fire-its-omega-rocket-first-stage-in-utah/1289351001/|title=Anomaly after Northrop Grumman successfully test fires Omega rocket in Utah|publisher=Florida Today|date=30 May 2019 |author=Emre Kelly}}</ref>

In 2019, NGIS bid the Omega launch vehicle to the US Air Force for the multi-year block buy launch contract that would cover all US national security launches in 2022–2026.<ref name=ars20190812>{{cite news |last=Berger|first=Eric |url=https://arstechnica.com/science/2019/08/four-rocket-companies-are-competing-for-air-force-funding-and-it-is-war/ |title=Four rocket companies are competing for Air Force funding, and it is war |work=[[Ars Technica]] |date=12 August 2019 |accessdate=21 August 2019 |quote=''The bet by Northrop is that the US military, through its national security launch contract, would want to support one of the nation's most critical suppliers of solid-rocket motors for intercontinental ballistic missiles. Northrop officials have not said whether they would continue development of the Omega rocket if Northrop were to lose out on the Air Force contract.''}}</ref>

==Multiple configurations==
The rocket will have two basic configurations, an intermediate and a heavy launch. The intermediate version will have a two segment, [[Shuttle-Derived Launch Vehicle|shuttle-derived launch vehicle]] (SDLV) 2-segment [[solid rocket booster]] (SRB) first stage, a single segment SRB second stage, and a liquid hydrogen fuelled third stage. The heavy configuration will have a 4-segment SRB first stage, and the same upper stages.<ref>{{Cite web|url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf|title=OmegA Factsheet|last=|first=|date=|website=Northrop Grumman|url-status=live|archive-url=|archive-date=|access-date=}}</ref> Additional versions are projected to add additional SRBs as side boosters. The [[Shuttle-Derived Launch Vehicle|SDLV]] SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }}</ref>

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

==References==
{{Reflist|2}}

==External links==
*[http://www.northropgrumman.com/Capabilities/Omega/Pages/default.aspx OmegA official web site]

{{S-start}}
{{Succession box
| title = Single-stick SRB-based [[Shuttle-Derived Launch Vehicle|SDLV]]
| years = 2016–
| before = [[Liberty (rocket)|Liberty]]
| after = Incumbent
}}
{{S-end}}

{{US launch systems}}
{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

OmegA

2019-11-21T20:43:07Z

Blastr42:

{{short description|US launch vehicle}}
{{redirect|OmegA|other uses|omega (disambiguation)}}
{{Infobox rocket
| name = Omega
| logo = Omega logo.svg
| logo_alt = Logo of OmegA
| image = OmegA rocket.jpeg
| caption =
| manufacturer = [[Northrop Grumman]]
| country-origin = [[United States]]
| height = {{convert|59.84|m|ft|sp=us}}
| diameter = {{convert|3.71|m|ft|sp=us}} first stage {{convert|5.25|m|ft|sp=us}} upper stage
| mass =
| stages = 3
| capacities =
{{Infobox rocket/payload
| location = [[Geostationary transfer orbit|GTO]]
| kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="omega-factsheet">{{cite web |url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf |title=OmegA Factsheet |publisher=[[Northrop Grumman]] |accessdate=24 October 2019}}</ref>
}}
{{Infobox rocket/payload
| location = [[Geostationary orbit|GEO]]
| kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="omega-factsheet" />
}}
| family = [[Shuttle-Derived Launch Vehicle]]
| derivatives = 
| comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
| status = Under development
| sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]]
| launches = 0
| success =
| fail =
| partial =
| first = 2021 (projected)<ref name="omega-factsheet" />
| stagedata =
{{Infobox rocket/stage
| type = booster
| diff = 
| stageno = 
| name = [[Graphite-Epoxy Motor|GEM-63XLT]]
| number = 2 to 6
| diameter = {{convert|63|in|m|order=flip|sp=us|abbr=on}}
| solid = yes
| total = 
| SI = {{convert|279.3|isp}}
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = First
| engines = [[Castor (rocket stage)|Castor]] 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| solid = yes
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Second
| engines = [[Castor (rocket stage)|Castor]] 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
| thrust =
| burntime =
| fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
| type = stage
| stageno = Third
| engines = 2 × [[RL10|RL-10C-5-1]]
| thrust = {{convert|22890|lbf|kN|order=flip}}
| SI = ~450 seconds (vacuum)
| burntime =
| fuel = [[LOX]]/[[LH2]]
}}
}}

'''Omega''', stylized as "'''OmegA'''", is a [[launch vehicle]] in development by [[Northrop Grumman]] as an [[National Security Space Launch|NSSL]] replacement program intended for national security and commercial satellites.<ref name=":0">{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have used a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne]]<ref name="SpaceNews-20180416">{{cite news |last1=Erwin |first1=Sandra |last2=Berger |first2=Brian |url=https://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/ |title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket |work=[[SpaceNews]] |date=16 April 2018 |access-date=18 April 2018 |language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 6|SLC-6]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spacenews.com/northrop-grumman-to-launch-omega-rocket-from-ulas-delta-4-pad-at-vandenberg/|title=Northrop Grumman to launch OmegA rocket from ULA’s Delta 4 pad at Vandenberg|last=Erwin|first=Sandra|date=26 October 2019|website=|publisher=Spaceflight Now|url-status=live|archive-url=|archive-date=|access-date=}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development was to start once the Air Force reached a funding decision. In October 2018, the Air Force announced that Northrop Grumman was awarded $792 million for initial development of the Omega launch vehicle.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

==History==
[[File:Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, [[Orbital ATK]] (now [[Northrop Grumman Innovation Systems]]) was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine for US national security payloads.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5–6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher took place in early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{failed verification|date=August 2019}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). The rocket would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor. The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}}.<ref name="omega-factsheet" /><ref name="SpaceNews-20180416" />

In October 2018, Omega was awarded a Launch Services Agreement worth $791,601,015 to design, build and launch the first Omega rockets.<ref name=SpaceNews-20181010>{{cite web|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force Awards Launch Vehicle Development Contracts to Blue Origin Northrop Grummand ULA|publisher=Space News|date=10 October 2018 |author=Sandra Erwin}}</ref>

In late May 2019, while conducting a static fire test of the first stage SRB, an anomaly occurred resulting in the destruction of the SRB nozzle (but not the stage itself).<ref name=SFloridaToday-20190530>{{cite web|url=https://www.floridatoday.com/story/tech/science/space/2019/05/30/live-watch-northrop-grumman-test-fire-its-omega-rocket-first-stage-in-utah/1289351001/|title=Anomaly after Northrop Grumman successfully test fires Omega rocket in Utah|publisher=Florida Today|date=30 May 2019 |author=Emre Kelly}}</ref>

In 2019, NGIS bid the Omega launch vehicle to the US Air Force for the multi-year block buy launch contract that would cover all US national security launches in 2022–2026.<ref name=ars20190812>{{cite news |last=Berger|first=Eric |url=https://arstechnica.com/science/2019/08/four-rocket-companies-are-competing-for-air-force-funding-and-it-is-war/ |title=Four rocket companies are competing for Air Force funding, and it is war |work=[[Ars Technica]] |date=12 August 2019 |accessdate=21 August 2019 |quote=''The bet by Northrop is that the US military, through its national security launch contract, would want to support one of the nation's most critical suppliers of solid-rocket motors for intercontinental ballistic missiles. Northrop officials have not said whether they would continue development of the Omega rocket if Northrop were to lose out on the Air Force contract.''}}</ref>

==Multiple configurations==
The rocket will have two basic configurations, an intermediate and a heavy launch. The intermediate version will have a two segment, [[Shuttle-Derived Launch Vehicle|shuttle-derived launch vehicle]] (SDLV) 2-segment [[solid rocket booster]] (SRB) first stage, a single segment SRB second stage, and a liquid hydrogen fuelled third stage. The heavy configuration will have a 4-segment SRB first stage, and the same upper stages.<ref>{{Cite web|url=https://www.northropgrumman.com/MediaResources/MediaKits/OmegARocket/pdf/OmegA_Factsheet.pdf|title=OmegA Factsheet|last=|first=|date=|website=Northrop Grumman|url-status=live|archive-url=|archive-date=|access-date=}}</ref> Additional versions are projected to add additional SRBs as side boosters. The [[Shuttle-Derived Launch Vehicle|SDLV]] SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }}</ref>

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

==References==
{{Reflist|2}}

==External links==
*[http://www.northropgrumman.com/Capabilities/Omega/Pages/default.aspx OmegA official web site]

{{S-start}}
{{Succession box
| title = Single-stick SRB-based [[Shuttle-Derived Launch Vehicle|SDLV]]
| years = 2016–
| before = [[Liberty (rocket)|Liberty]]
| after = Incumbent
}}
{{S-end}}

{{US launch systems}}
{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

Lunar Gateway

2019-07-23T16:05:54Z

Blastr42: /* Contracted modules */

{{Use American English|date=March 2017}}
{{Use dmy dates|date=July 2019}}
{{Infobox space station
| spelling = us
| station = Lunar Orbital Platform – Gateway
| station_image = Lunar Orbital Platform-Gateway.jpg
| station_image_landscape=
| station_image_size =
| station_image_alt =
| station_image_caption = Artist's concept of Lunar Orbital Platform – Gateway orbiting the [[Moon]]. The [[Orion MPCV]] is docked on the left.
| extra_image =
| extra_image_landscape =
| extra_image_size =
| extra_image_alt =
| extra_image_caption =
| insignia =
| insignia_size =
| insignia_alt =
| insignia_caption =
| NSSDC_ID =
| SATCAT =
| sign =
| crew =4 (proposed)
| launch =
| carrier_rocket =[[Space Launch System]] Commercial launch vehicles [[Proton-M]] [[Angara (rocket family)|Angara]] <ref>[http://www.russianspaceweb.com/imp.html First human outpost near the Moon.] Anatoly Zak, ''Russian Space Web''.</ref><ref>[https://www.space.com/42566-russians-struggle-to-keep-soyuz-reliable.html Russians Are Struggling to Keep Soyuz Reliable, Space Expert Warns Ahead of Crew Launch.] Elizabeth Howell, ''Space.com''. November 29, 2018.</ref>
| launch_pad =
| launch_date = Planned: 2022<ref>{{Cite web|url=http://www.nasa.gov/feature/questions-nasas-new-spaceship|title=Q&A: NASA's New Spaceship|last=Mahoney|first=Erin|date=2018-10-30|website=NASA|access-date=2019-07-09}}</ref>
| reentry =
| status = PPE and ESPRIT<ref name='ESPRIT Zak'/> modules in development. General station architecture still undefined.
| mass =
| length =
| width =
| height =
| diameter =
| volume = Proposed: {{convert|4414.33|cuft|m3|order=flip|sigfig=5|abbr=on}}
| pressure =
| perigee =
| apogee =
| inclination =
| altitude =
| speed =
| period =
| orbits_day =
| in_orbit =
| occupied =
| orbits =
| distance =
| as_of =
| stats_ref =
| configuration_image =
| configuration_landscape=
| configuration_size =
| configuration_alt =
| configuration_caption =
| programme = [[Artemis program]]
}}

The '''Lunar Orbital Platform – Gateway''' ('''LOP-G''') is a future [[space station]] in [[lunar orbit]] intended to serve as a solar-powered communications hub, science laboratory, short-term habitation module, and holding area for rovers and other robots.<ref name="Jackson20180911">{{cite web |last1=Jackson |first1=Shanessa |title=Competition Seeks University Concepts for Gateway and Deep Space Exploration Capabilities |url=https://www.nasa.gov/feature/competition-seeks-university-concepts-for-gateway-and-deep-space-exploration-capabilities |website=nasa.gov |publisher=NASA |accessdate=19 September 2018 |date=11 September 2018}}</ref>

While the project is led by [[NASA]], the Gateway is meant to be developed, serviced, and utilized in collaboration with commercial and international partners. It will serve as the staging point for robotic and [[Artemis program|crewed exploration]] of the [[lunar south pole]], and is the proposed staging point for NASA's [[Deep Space Transport]] concept.<ref>{{cite web |last=Gebhardt |first=Chris |title=NASA finally sets goals, missions for SLS – eyes multi-step plan to Mars |url=https://www.nasaspaceflight.com/2017/04/nasa-goals-missions-sls-eyes-multi-step-mars/ |website=NASASpaceflight.com |publisher=NASA Spaceflight |accessdate=19 September 2018 |date=6 April 2017}}</ref><ref name="Gateway_20170328">{{cite web |last1=Kathryn Hambleton |title=Deep Space Gateway to Open Opportunities for Distant Destinations |website=www.nasa.gov |url=https://www.nasa.gov/feature/deep-space-gateway-to-open-opportunities-for-distant-destinations|publisher=NASA |accessdate=April 5, 2017}}</ref><ref name="NASA_March_2017">{{cite web |last1=Robyn Gatens |first1=Jason Crusan |title=Cislunar Habitation & Environmental Control & Life Support System |url=https://www.nasa.gov/sites/default/files/atoms/files/20170329-nacheoc-crusan-gatens-hab-eclss-v5b.pdf |website=www.nasa.gov |publisher=NASA |accessdate=March 31, 2017 }}</ref>

The science disciplines to be studied on the Gateway are expected to include planetary science, astrophysics, Earth observations, heliophysics, fundamental space biology, and human health and performance.<ref name="Mahoney-20180824">{{cite web |last1=Mahoney |first1=Erin |title=NASA Seeks Ideas for Scientific Activities Near the Moon |url=https://www.nasa.gov/feature/nasa-seeks-ideas-for-scientific-activities-near-the-moon |website=nasa.gov |publisher=NASA |accessdate=19 September 2018 |date=24 August 2018}}</ref> Under current plans, this scientific activity will start after the first crewed landing ([[Artemis 3]]).{{citation_needed|date=July 2019}}

Gateway development includes all of the [[International Space Station]] partners: [[ESA]], [[NASA]], [[Roscosmos]], [[JAXA]], and [[Canadian Space Agency|CSA]]. Construction is planned to take place in the 2020s.<ref name="Gateway_20170328" /><ref name="roscosmos20170929">{{cite web |title="РОСКОСМОС - NASA. СОВМЕСТНЫЕ ИССЛЕДОВАНИЯ ДАЛЬНЕГО КОСМОСА (ROSCOSMOS - NASA. JOINT RESEARCH OF FAR COSMOS)" |url=https://www.roscosmos.ru/24136 |accessdate=September 29, 2017}}</ref><ref name="Weitering 2017">{{cite news |last=Weitering |first=Hanneke |url=https://www.space.com/38287-nasa-russia-deep-space-gateway-partnership.html |title=NASA and Russia Partner Up for Crewed Deep-Space Missions |work=Space.com |date=27 September 2017 |accessdate=2017-11-05 }}</ref> The International Space Exploration Coordination Group (ISECG), which is composed of 14 space agencies including NASA, has concluded that LOP-G will be critical in expanding a human presence to the Moon, Mars, and deeper into the Solar System.<ref>{{cite web |author1=NASA |title=Gateway Memorandum for the Record |url=https://www.nasa.gov/sites/default/files/atoms/files/gateway_domestic_and_international_benefits-memo.pdf |website=nasa.gov |publisher=NASA |accessdate=19 September 2018 |date=2 May 2018}}</ref> Formerly known as the '''Deep Space Gateway''', the station was renamed in NASA's 2018 proposal for the 2019 United States federal budget.<ref>{{cite web|last1=Davis|first1=Jason|title=Some snark (and details!) about NASA's proposed lunar space station|url=http://www.planetary.org/blogs/jason-davis/2018/20180226-lop-g-snark-details.html|publisher=[[The Planetary Society]]|accessdate=February 26, 2018|archiveurl=https://web.archive.org/web/20180226175759/http://www.planetary.org/blogs/jason-davis/2018/20180226-lop-g-snark-details.html|archivedate=February 26, 2018|language=en-US|date=February 26, 2018}}</ref><ref>{{Cite web|url=https://www.theguardian.com/science/2018/feb/12/trump-nasa-budget-moon-flying-cars-plans|title=Trump's Nasa budget: flying 'Jetson cars' and a return to the moon|last=Yuhas|first=Alan|date=2018-02-12|website=the Guardian|language=en|access-date=2018-02-25}}</ref> When the budgeting process was complete, US$450 million had been committed by Congress to preliminary studies.<ref>{{cite web| last=Foust| first=Jeff| title=Senate bill restores funding for NASA science and technology demonstration missions| url=https://spacenews.com/senate-bill-restores-funding-for-nasa-science-and-technology-demonstration-missions/| publisher=[[Space News]]|accessdate=September 16, 2018|language=en-US|date=June 12, 2018}}</ref><ref>{{Cite web|url=http://www.planetary.org/blogs/casey-dreier/2019/0215-fy2019-nasa-gets-its-best-budget-in-decades.html|title=NASA just got its best budget in a decade|website=www.planetary.org|language=en|access-date=2019-02-27}}</ref>

==Contracted modules==
* The '''Power and Propulsion Element''' (PPE) started development at the [[Jet Propulsion Laboratory]] during the now canceled [[Asteroid Redirect Mission]]. The original concept was a robotic, high performance [[Ion thruster|solar electric]] spacecraft that would retrieve a multi-ton boulder from an asteroid and bring it to lunar orbit for study.<ref>{{Cite web|url=http://www.nasa.gov/feature/jpl/jpl-seeks-robotic-spacecraft-development-for-asteroid-redirect-mission|title=JPL Seeks Robotic Spacecraft Development for Asteroid Redirect Mission|last=Greicius|first=Tony|date=2016-09-20|website=NASA|access-date=2019-05-30}}</ref> When ARM was cancelled, the solar electric propulsion was repurposed for LOP-G.<ref>{{Cite web|url=https://spacenews.com/nasa-closing-out-asteroid-redirect-mission/|title=NASA closing out Asteroid Redirect Mission|date=2017-06-14|website=SpaceNews.com|language=en-US|access-date=2019-05-30}}</ref><ref>{{Cite web|url=https://www.jpl.nasa.gov/missions/asteroid-redirect-robotic-mission-arrm/|title=Asteroid Redirect Robotic Mission|website=www.jpl.nasa.gov|access-date=2019-05-30}}</ref> The PPE will allow access to the entire lunar surface and act as a [[space tug]] for visiting craft.<ref>{{Cite web|url=http://www.aerotechnews.com/blog/2019/05/24/nasa-awards-artemis-contract-for-lunar-gateway-power-propulsion/|title=NASA awards Artemis contract for lunar gateway power, propulsion|last=**|date=2019-05-25|website=Aerotech News & Review|language=en-US|access-date=2019-05-30}}</ref> It will also serve as the command and communications center of the Gateway.<ref>{{Cite web|url=http://www.sci-news.com/space/deep-space-gateway-transport-mars-moon-exploration-04756.html|title=Deep Space Gateway & Transport: Concepts for Mars, Moon Exploration Unveiled {{!}} Space Exploration {{!}} Sci-News.com|website=Breaking Science News {{!}} Sci-News.com|language=en-US|access-date=2019-05-30}}</ref><ref>{{Cite web|url=https://spaceflightnow.com/2019/05/24/nasa-chooses-maxar-to-build-keystone-module-for-lunar-gateway-station/|title=NASA chooses Maxar to build keystone module for lunar Gateway station – Spaceflight Now|last=Clark|first=Stephen|language=en-US|access-date=2019-05-30}}</ref> The PPE is intended to have a mass of 8-9 t and the capability to generate 50 kW<ref name='Nov 3'>[http://spacenews.com/nasa-issues-study-contracts-for-deep-space-gateway-element/ NASA issues study contracts for Deep Space Gateway element]. Jeff Foust, ''Space News''. 3 November 2017.</ref> of [[solar electric power]] for its [[ion thruster]]s, which can be supplemented by chemical propulsion.<ref name="Flight_20170406">{{cite web |last1=Chris Gebhardt |title=NASA finally sets goals, missions for SLS – eyes multi-step plan to Mars |url=https://www.nasaspaceflight.com/2017/04/nasa-goals-missions-sls-eyes-multi-step-mars |website=NASA Spaceflight |accessdate=April 9, 2017 }}</ref> It is targeting launch on a commercial vehicle in 2022.<ref name='NASA_budget_2019'>{{Cite web|url=https://www.nasa.gov/sites/default/files/atoms/files/nasa_fy_2019_budget_overview.pdf|title=NASA FY 2019 Budget Overview|last=|first=|date=|website=|access-date=}} Quote: "Supports launch of the Power and PropulsionElement on a commercial launch vehicle as the first component of the LOP - Gateway, (page 14)</ref><ref>[http://spacenews.com/nasa-considers-acquiring-more-than-one-gateway-propulsion-module/ NASA considers acquiring more than one gateway propulsion module]. Joe Faust, ''Space News''. 30 March 2018.</ref> In May 2019, [[Maxar Technologies]] was contracted by NASA to manufacture this module, which will also supply the station with electrical power and is based on Maxar's 1300 series [[satellite bus]].<ref name="PPE_Maxar">{{cite news |last1=Jeff Foust |title=NASA selects Maxar to build first Gateway element |url=https://spacenews.com/nasa-selects-maxar-to-build-first-gateway-element |accessdate=May 23, 2019 |work=SpaceNews |date=May 23, 2019}}</ref> Maxar was awarded a firm-fixed price contract of $375 million to build the PPE. NASA is supplying the PPE with an S-band communications system to provide a radio link with nearby vehicles and a passive docking adapter to receive the Gateway’s future utilization module.<ref name="Maxar_PPE_20190524">{{cite news |last1=Stephen Clark |title=NASA chooses Maxar to build keystone module for lunar Gateway station |url=https://spaceflightnow.com/2019/05/24/nasa-chooses-maxar-to-build-keystone-module-for-lunar-gateway-station |accessdate=July 13, 2019 |work=Spaceflight Now |date=May 24, 2019}}</ref>

* The '''Minimal Habitation Module''' (MHM)<ref name="MHM_20190719">{{cite web |title=GATEWAY PROGRAM MODULE(S) Continued use of NextSTEP-2 Broad Agency Announcement (BAA) Appendix A |url=https://www.fbo.gov/index.php?s=opportunity&mode=form&tab=core&id=36ebf3fc4d57c88b6bd8c94d1806dfb9&_cview=1 |website=Federal Business Opportunities |publisher=NASA |accessdate=23 July 2019 |ref=Solicitation 80JSC019GTWYHAB}}</ref> will be built by Northrop Grumman Innovation Systems (NGIS). A commercial launch vehicle will launch the MHM before the end of year 2023. The MHM is based on a [[Cygnus_(spacecraft)|Cygnus]] Cargo resupply module to the outside of which radial docking ports, body mounted radiators (BMRs), batteries and communications antennae will be added.<ref name="MHM_requirements_justification"/> The MHM will be a functional pressurized volume providing sufficient command, control & data handling capabilities, energy storage and power distribution, thermal control, communications and tracking capabilities, environmental control and life support systems to augment the Orion spacecraft and support a crew of four for at least 30 days; two axial and up to two radial docking ports; stowage volume; and utilization capabilities.<ref name="MHM_requirements_justification">{{cite web |title=JUSTIFICATION FOR OTHER THAN FULL AND OPEN COMPETITION (JOFOC) FOR THE MINIMAL HABITATION MODULE (MHM) |url=https://www.fbo.gov/index.php?tab=documents&tabmode=form&subtab=core&tabid=d4e9e11d78e9dd0b8bd05395b3d82c7f |website=Federal Business Opportunities |publisher=NASA |accessdate=23 July 2019 |ref=Solicitation 80JSC019GTWYHAB}}</ref>

==Current planning==
[[File:Gateway Space Station Module Map.jpg|thumb|right|upright=1.25|March 2019 concept. The Gateway will serve as a solar-powered communications hub, science laboratory, short-term habitation module, refueling depot, and holding area for crewed and robotic landers and robots.]]
[[File:LOP-G_General_Information.jpg|thumb|right|upright=1.25|The Gateway advances NASA's goals of sustaining human space exploration and serves as a platform to further cislunar operations, lunar surface access and missions to Mars.]]
[[File:LOP-G interior with Astronauts.jpg|thumb|right|Four astronauts inside the LOP-G space station mock-up module at the [[Space Station Processing Facility]].]]
[[File:LOP-G_module_training_mock-up_module_group_photo.jpg|thumb|right|NASA and Lockheed Martin employees group photo with one of the LOP-G space station modules training mock-up inside the SSPF]]
The LOP-G is currently intended to be placed in a highly elliptical six-day near-rectilinear [[halo orbit]] (NRHO) around the Moon, which would bring the station within {{convert|1500|km|abbr=on}} of the lunar surface at closest approach and as far away as {{convert|70000|km|abbr=on}}.<ref>[https://www.space.com/41763-nasa-lunar-orbiting-platform-gateway-basics.html Mike Wall, ''Space.com''. 10 September 2018.]</ref> Traveling to and from cislunar space (lunar orbit) is intended to develop the knowledge and experience necessary to venture beyond the Moon and into deep space.

The proposed NRHO orbit would allow lunar expeditions from the Gateway to reach a [[polar orbit|polar]] low lunar orbit with a [[delta-v]] of 730 m/s and a half a day of transit time. [[Orbital station-keeping]] would require less than 10 m/s of delta-v per year, and the [[orbital inclination]] could be shifted with a relatively small delta-v expenditure, allowing access to most of the lunar surface.<ref>{{cite web |last1=Whitley |first1=Ryan |last2= Martinez |first2=Roland |title=Options for Staging Orbits in Cis-Lunar Space |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150019648.pdf
|website=nasa.gov |publisher=NASA |accessdate=19 September 2018 |date=21 October 2015}}</ref>

The Gateway could conceivably also support [[in-situ resource utilization]] (ISRU) development and testing from lunar and [[Asteroid mining|asteroid]] sources,<ref>[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180002054.pdf Research Possibilities Beyond Deep Space Gateway]. David Smitherman, Debra Needham, Ruthan Lewis. NASA. February 28, 2018.</ref> and would offer the opportunity for gradual buildup of capabilities for more complex missions over time.<ref name='Free 2017>[https://www.nasa.gov/sites/default/files/atoms/files/march_2017_nac_charts_architecturejmf_rev_3_tagged.pdf Human Exploration and Operations Mission Directorate - Architecture Status]. (PDF) Jim Free. NASA. 28 March 2017.</ref> Various components of the Gateway would be launched on commercial launch vehicles and on the [[Space Launch System]] as Orion co-manifested payloads on the Artemis 4 through Artemis 8 missions.<ref name="Insider20170401">{{cite news |last=Godwin |first=Curt |url=http://www.spaceflightinsider.com/organizations/nasa/nasa-human-spaceflight-plans-focus-announcement-deep-space-gateway/ |title=NASA's human spaceflight plans come into focus with announcement of Deep Space Gateway |newspaper=Spaceflight Insider |date=April 1, 2017 |accessdate=2017-04-02 }}</ref> According to [[Roscosmos]], they may also use [[Proton-M]] and [[Angara (rocket family)|Angara-A5M]] heavy launchers to fly payloads or crew.<ref name="Weitering 2017"/>

All modules will be connected using the [[International Docking System Standard]].<ref name="Inverse 2017">[https://www.inverse.com/article/29948-nasa-deep-space-gateway-transport-architectures-mars-travel NASA Unveils the Keys to Getting Astronauts to Mars and Beyond]. Neel V. Patel, ''The Inverse''. April 4, 2017.</ref>

===Proposed modules===
The concept for the lunar Gateway is still evolving, and is currently intended to include the following modules:<ref>{{cite web|url=https://www.nasa.gov/sites/default/files/atoms/files/20180327-crusan-nac-heoc-v8.pdf |title=Future Human Exploration Planning:Lunar Orbital Platform – Gateway and Science Workshop Findings|last=Cursan|first=Jason|date=March 27, 2018|website=|access-date=April 13, 2018}}</ref>

* The '''European System Providing Refuelling, Infrastructure and Telecommunications''' (ESPRIT) module will provide additional xenon and hydrazine capacity, additional communications equipment, and an airlock for science packages.<ref name=nsf-20180911>{{cite web |title=NASA updates Lunar Gateway plans |date=September 11, 2017 |first=Philip |last=Sloss |url=https://www.nasaspaceflight.com/2018/09/nasa-lunar-gateway-plans/ |website=NASASpaceFlight.com |access-date=2017-09-15}}</ref> It would have a mass of approximately {{cvt|4|t|lb}}, and a length of {{cvt|3.91|m}}.<ref name='ESPRIT Zak'>[http://www.russianspaceweb.com/imp-lcub.html ESA develops logistics vehicle for cis-lunar outpost]. Anatoly Zak, ''Russian Space Web''. September 8, 2018.</ref>

* The '''International Partner Habitat''' and the '''Minimal Habitation Module''' are the two habitation modules. The International Partner Habitat will be launched on Artemis 4 or Artemis 5 and together will provide a minimum of {{cvt|125|m3}} of habitable volume to the station.<ref name=nsf-20180911/>
* The '''Gateway Logistics Modules''' will be used to refuel, resupply and provide logistics on board the space station. The first logistics module sent to LOP-G will also arrive with a robotic arm, which will be built by the [[Canadian Space Agency]].<ref>{{cite news |last1=Mortillaro |first1=Nicole |title=Canada's heading to the moon: A look at the Lunar Gateway |url=https://www.cbc.ca/news/technology/canada-lunar-gateway-1.5037522 |accessdate=March 2, 2019 |work=CBC News |date=February 28, 2019 |language=en}}</ref><ref>{{Cite news|url=https://globalnews.ca/news/3775926/canadian-space-agency-robotic-arms/|title=Canadian Space Agency to build robotic arms for lunar space station|work=Global News|access-date=2017-09-29|language=en}}</ref>
* The '''Gateway Airlock Module''' will be used for performing [[Extravehicular activity|extravehicular activities]] outside the space station and would have the docking port for the proposed [[Deep Space Transport]].

===Proposed timeline===
{| class="wikitable"
|-
! Year !! Vehicle assembly objective !! Mission name !! Launch vehicle !! Human/robotic elements
|-
| Q4 2022<ref>{{cite web |last1=Foust |first1=Jeff |title=Shutdown to delay first element of NASA’s lunar Gateway |url=https://spacenews.com/shutdown-to-delay-first-element-of-nasas-lunar-gateway/ |website=Spacenews.com |publisher=Spacenews |accessdate=28 February 2019 |date=27 February 2019 |quote=NASA stated in the procurement filing that it expects “a corresponding shift in the target launch date from September 2022 to no later than December 31, 2022.”}}</ref> || Launch of the Power and Propulsion Element (PPE)<ref>{{cite web |url=https://www.nasa.gov/feature/nasa-s-first-flight-with-crew-will-mark-important-step-on-journey-to-mars |title= Crew Will Mark Important Step on Journey to Mars |first=Gary |last=Daines |date=December 1, 2016 |website=Nasa.gov|accessdate=2 January 2018}}</ref> || {{TBA}} || Commercial launch vehicle<ref name='NASA_budget_2019'/><ref name='Gates 2018'>[https://www.nasa.gov/sites/default/files/atoms/files/ppe_nac_heo.pdf Status of Power and Propulsion Element (PPE) for Gateway]. (PDF) Michele Gates, NASA's NAC HEO Committee Meeting
August 27, 2018.</ref> || Uncrewed
|-

| 2023 || ESPRIT and US Utilization Module<ref name=":2">{{Cite web| url=https://www.nasa.gov/specials/moon2mars/#four|title=NASA's roadmap for Artemis| date=2019-05-23|website=Nasa.gov|language=en-US|archive-url=|archive-date=|dead-url=|access-date=2019-05-15}}</ref> || {{TBA}} || Commercial launch vehicle || Uncrewed
|-

| 2023 || Three components of an expendable lunar lander<ref name="a3-1">{{Harvard citation no brackets|Foust|2019|loc="And before NASA sends astronauts to the moon in 2024, the agency will first have to launch five aspects of the lunar Gateway, all of which will be commercial vehicles that launch separately and join each other in lunar orbit. First, a power and propulsion element will launch in 2022. Then, the crew module will launch (without a crew) in 2023. In 2024, during the months leading up to the crewed landing, NASA will launch the last critical components: a transfer vehicle that will ferry landers from the Gateway to a lower lunar orbit, a descent module that will bring the astronauts to the lunar surface, and an ascent module that will bring them back up to the transfer vehicle, which will then return them to the Gateway."}}</ref> || {{TBA}} || Commercial launch vehicles || Uncrewed
|-

| 2024 || Orion docking to the Gateway, followed by a lunar landing and return to the Gateway<ref name=":2"/> || [[Artemis 3]] || Space Launch System, Block 1B || Crewed
|-
| 2025 || Orion will deliver the U.S. Habitation module; lunar landing. || Artemis 4 || Space Launch System, Block 1B || Crewed
|-
| 2026 || Orion will deliver U.S. Habitat; lunar landing || Artemis 5 || Space Launch System, Block 1B || Crewed
|-
| 2027 || Orion will deliver the first logistics module and the robotic arm<ref name=nsf-20180911 />
|| Artemis 6 || Space Launch System, Block 1B || Crewed
|-
| 2028 || Deliver a logistics module || Artemis 8 || Space Launch System, Block 1B || Uncrewed
|-
|}

==History==
[[File:ISS-Derived Deep Space Habitat with CPS.jpg|thumb|right|upright=1.25|Deep Space Habitat concept.]]
===Studies===
An earlier NASA proposal for a cislunar station had been made public in 2012 and was dubbed the [[Deep Space Habitat]]. That proposal had led to funding in 2015 under the NextSTEP program to study the requirements of deep space habitats.<ref>{{cite news |last1=Doug Messier on |title=A Closer Look at NextSTEP-2 Deep Space Habitat Concepts |url=http://www.parabolicarc.com/2016/08/11/deep-space-habitat-concepts |accessdate=September 19, 2018 |publisher=Parabolic Arc |date=August 11, 2016}}</ref>
In February 2018, it was announced that the NextSTEP studies and other ISS partner studies would help to guide the capabilities required of the Gateway's habitation modules.<ref>{{cite web |last1=Warner |first1=Cheryl |title=NASA's Lunar Outpost will Extend Human Presence in Deep Space |url=https://www.nasa.gov/feature/nasa-s-lunar-outpost-will-extend-human-presence-in-deep-space |website=nasa.gov |publisher=NASA |accessdate=19 September 2018 |date=2 May 2018}}</ref>

On 27 September 2017, an informal joint statement on cooperation between NASA and Russia's [[Roscosmos]] was announced.<ref name="Weitering 2017"/> The solar electric Power and Propulsion Element (PPE) of the Gateway was originally a part of the now cancelled [[Asteroid Redirect Mission]].<ref>[https://www.space.com/37619-nasa-deep-space-gateway-module-outreach.html NASA Seeks Information on Developing Deep Space Gateway Module]. Jeff Foust, ''Space.'' 29 July 2017.</ref><ref name='Nov 3'/>

On 7 November 2017, NASA asked the global science community to submit concepts for scientific studies that could take advantage of the Gateway's location in cislunar space.<ref name="Mahoney-20180824" /> The Deep Space Gateway Concept Science Workshop was held in Denver, Colorado from February 27 to March 1, 2018. This three-day conference was a workshop where 196 presentations were given for possible scientific studies that could be advanced through the use of the Gateway.<ref>{{cite web |title=Program and Presenter Information |url=https://www.hou.usra.edu/meetings/deepspace2018/program/ |website=Lunar and Planetary Institute |publisher=Universities Space Research Association |accessdate=19 September 2018}}</ref>

In 2018, NASA initiated a Revolutionary Aerospace Systems Concepts Academic Linkage (RASC-AL) competition for universities to develop concepts and capabilities for the Gateway. The competitors are asked to employ original engineering and analysis in one of the following areas:
* Gateway Uncrewed Utilization & Operations
* Gateway-Based Human Lunar Surface Access
* Gateway Logistics as a Science Platform
* Design of a Gateway-Based Cislunar Tug
Teams of undergraduate and graduate students were asked to submit a response by 17 January 2019 addressing one of these four themes. NASA will select 20 teams to continue developing proposed concepts. Fourteen of the teams presented their projects in person in June 2019 at the RASC-AL Forum in Cocoa Beach, Florida, receiving a $6,000 stipend to participate in the Forum.<ref name="Jackson20180911" /> [http://rascal.nianet.org/wp-content/uploads/2019/06/2019-RASCAL-Technical-Paper_University-of-Puerto-Rico-Mayaguez.pdf/ "Lunar Exploration and Access to Polar Regions"] from the University of Puerto Rico at Mayagüez was the winning concept.<ref>{{cite web |url=https://www.nasa.gov/feature/students-blaze-new-trails-in-nasa-space-exploration-design-competition |title=Students Blaze New Trails in NASA Space Exploration Design Competition |last= |first= |date=21 June 2019 |website= |publisher= |access-date=5 July 2019 |quote=}}</ref>

===Power and propulsion===

On 1 November 2017, NASA commissioned 5 studies lasting four months into affordable ways to develop the Power and Propulsion Element (PPE), hopefully leveraging private companies' plans. These studies had a combined budget of $2.4 million. The companies performing the PPE studies are [[Boeing]], [[Lockheed Martin]], [[Orbital ATK]], [[Sierra Nevada Corporation|Sierra Nevada]] and [[Space Systems]]/Loral.<ref name="NASA_PPE_studies">{{cite web |last1=Jimi Russell |title=NASA Selects Studies for Gateway Power and Propulsion Element |url=https://www.nasa.gov/press-release/nasa-selects-studies-for-gateway-power-and-propulsion-element |website=NASA.GOV |accessdate=November 2, 2017 }}</ref><ref name='Nov 3'/> These awards are in addition to the ongoing set of [[Next Space Technologies for Exploration Partnerships|NextSTEP-2]] awards made in 2016 to study development and make ground prototypes of habitat modules that could be used on the Lunar Orbital Platform – Gateway as well as other commercial applications,<ref name="NASA_March_2017"/> so the LOP-G is likely to incorporate components developed under NextSTEP as well.<ref name='Nov 3'/><ref name="Ground_Prototypes20070728">{{cite web |last1=Erin Mahoney |title=NextSTEP Partners Develop Ground Prototypes to Expand our Knowledge of Deep Space Habitats |url=https://www.nasa.gov/feature/nextstep-partnerships-develop-ground-prototypes |website=NASA.GOV |publisher=NASA |accessdate=November 6, 2017 }}</ref>

NASA officials stated that the most likely [[Solar electric propulsion|ion engine]] to be used on the PPE is the 14 kW [[Hall thruster]] called [[Advanced Electric Propulsion System]] (AEPS) which has an [[Specific impulse|I''sp'']] of up to 2,600 s. The engine is being developed by [[Glenn Research Center]], the [[Jet Propulsion Laboratory]], and [[Aerojet Rocketdyne]].<ref name='AEPS 2017'>[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180001297.pdf Overview of the Development and Mission Application of the Advanced Electric Propulsion System (AEPS)]. (PDF). Daniel A. Herman, Todd A. Tofil, Walter Santiago, Hani Kamhawi, James E. Polk, John S. Snyder, Richard R. Hofer, Frank Q. Picha, Jerry Jackson and May Allen. NASA; NASA/TM—2018-219761. 35th International Electric Propulsion Conference.
Atlanta, Georgia, October 8–12, 2017. Accessed: 27 July 2018.</ref> Four identical AEPS engines would consume the 50 kW generated.<ref name='AEPS 2017'/>

In 2019, the contract to manufacture the PPE was awarded to a division of [[Maxar Technologies]] (formerly [[SSL (company)|SSL]]).<ref name="Maxar">[https://www.nasa.gov/press-release/nasa-awards-artemis-contract-for-lunar-gateway-power-propulsion NASA Awards Artemis Contract for Lunar Gateway Power, Propulsion] Nasa, 23 May 2019</ref> After a one-year demonstration period, NASA would then "exercise a contract option to take over control of the spacecraft."<ref>[https://www.nasaspaceflight.com/2018/09/nasa-lunar-gateway-plans/ NASA updates Lunar Gateway plans]. Philip Sloss, ''NASA Spaceflight.com''. 11 September 2018.</ref>

==Criticisms==
The lunar Gateway has received criticisms from several space professionals as lacking a proper, focused scientific goal. NASA officials promote the Gateway as a "reusable command module" that could direct activities on the lunar surface.<ref name='SN Foust 25 Dec 2018'>[https://spacenews.com/is-the-gateway-the-right-way-to-the-moon/ Is the Gateway the right way to the moon?] Jeff Foust, ''Space News''. 25 December 2018.</ref>

In May 2018, three major criticisms were aired. Former NASA Astronaut [[Terry W. Virts]], who was a pilot of [[STS-130]] aboard [[Space Shuttle Endeavour|Space Shuttle ''Endeavour'']] and Commander of the [[International Space Station]] on [[Expedition 43]], wrote in an Op-ed on ''[[Ars Technica]]'' that the lunar Gateway would "shackle human exploration, not enable it". Terry stated that there is no concrete human spaceflight goal with the Gateway and that he cannot envision a new technology that would be developed or validated by building another modular space station. Terry further criticized NASA for abandoning its planned goal of separating crew from cargo, which was put in place following the [[Space Shuttle Columbia disaster|Space Shuttle ''Columbia'' disaster]] in 2003.<ref>{{cite web |title=Op-ed: The Deep Space Gateway would shackle human exploration, not enable it |url=https://arstechnica.com/science/2017/09/op-ed-the-deep-space-gateway-would-shackle-human-exploration-not-enable-it/ |publisher=[[Ars Technica]] |accessdate=May 20, 2018}}</ref> [[Mars Society]] founder [[Robert Zubrin]], who has consistently advocated a [[human mission to Mars]], called the lunar Gateway "NASA's worst plan yet" in an article in the ''[[National Review]]''. Zubrin went on to state that, in his opinion, the proposed Gateway would not be useful to go to the Moon, Mars, near-Earth asteroids, or any other possible destination. He also stated that the ISS could accomplish many of the goals for the Gateway, and that "there is nothing at all in lunar orbit". Zubrin also stated that "If the goal is to build a Moon base, it should be built on the surface of the Moon. That is where the science is, that is where the shielding material is, and that is where the resources to make propellant and other useful things are to be found."<ref>{{cite web |title=NASA’s Worst Plan Yet |url=https://www.nationalreview.com/2017/05/nasa-lunar-orbit-space-station-terrible-idea/ |publisher=[[National Review]] |accessdate=May 20, 2018}}</ref> Retired aerospace engineer Gerald Black stated that the "LOP-G is useless for supporting human return to the lunar surface and a lunar base." He added that it was not planned to be used as a rocket fuel depot and that stopping at LOP-G on the way to or from the Moon would serve no useful purpose and cost propellant.<ref>[http://thespacereview.com/article/3494/1 The Lunar Orbital Platform – Gateway: an unneeded and costly diversion]. Gerald Black, ''The Space Review''. 14 May 2018.</ref>

In July 2018, Pei Zhaoyu, deputy director of the [[Chinese Lunar Exploration Program|Lunar Exploration and Space Program Center]] of the [[China National Space Administration]], concluded that, from a cost-benefit standpoint, the gateway would have "lost cost-effectiveness."<ref>{{cite web |last1=Berger |first1=Eric |title=Chinese space official seems unimpressed with NASA’s lunar gateway |url=https://arstechnica.com/science/2018/07/chinese-space-official-seems-unimpressed-with-nasas-lunar-gateway/ |website=[[Ars Technica]] |accessdate=17 July 2018}}</ref> Pei said the Chinese plan is to focus on a research station on the surface.<ref>{{cite web |last1=Kapoglou |first1=Angeliki |url=https://twitter.com/Capoglou/status/1018793732626440192 |website=[[Twitter]] |title=twitter.com/Capoglou|accessdate=17 July 2018}}</ref>

In December 2018, four major criticisms were aired. [[Michael D. Griffin]], a former NASA administrator, said that in his opinion, the Gateway can be useful only after there are facilities on the Moon producing propellant that could be transported to the Gateway. Griffin thinks that after that is achieved, the Gateway would then best serve as a fuel depot.<ref name='SN Foust 25 Dec 2018'/> Former [[Apollo 11]] astronaut [[Buzz Aldrin]] stated that he is "quite opposed to the Gateway" and that "using the Gateway as a staging area for robotic or human missions to the lunar surface is absurd." Aldrin also questioned the benefit of "send[ing] a crew to an intermediate point in space, pick[ing] up a lander there and go[ing] down" On the other hand, Aldrin expressed support for Robert Zubrin's Moon Direct concept which involves lunar landers traveling from Earth orbit to the lunar surface and back.<ref name="spacenews_lunar-exploration-plans">{{cite web |last1=Foust |first1=Jeff |title=Advisory group skeptical of NASA lunar exploration plans |url=https://spacenews.com/advisory-group-skeptical-of-nasa-lunar-exploration-plans/ |website=[[Ars Technica]] |accessdate=20 December 2018}}</ref> Former NASA Astronauts [[Eileen Collins]], who was a Space Shuttle pilot and commander, and [[Harrison Schmitt]], who was Lunar Module pilot aboard [[Apollo 17]], criticized NASA's plans for not being ambitious enough. Although they did not mention the Gateway directly, Collins stated that "2028 for humans on the moon seems like it's so far off" and that "we can do it sooner", while Schmitt stated that "the pace of the proposed program didn't match what took place under Apollo."<ref name="spacenews_lunar-exploration-plans"/> Mark Whittington, who is a contributor to ''[[The Hill (newspaper)|The Hill]]'' newspaper and an author of several space exploration studies, stated in an article that the "lunar orbit project doesn’t help us get back to the Moon". Whittington also pointed out that a lunar orbiting space station was not utilized during the Apollo program and that a "reusable lunar lander could be refueled from a depot on the lunar surface and left in a parking orbit between missions without the need for a big, complex space station."<ref>{{cite web |last1=Whittington |first1=Mark |title=NASA’s unnecessary $504 million lunar orbit project doesn’t help us get back to the Moon |url=https://thehill.com/opinion/technology/392611-nasas-unnecessary-504-million-lunar-orbit-project-doesnt-help-us-get-back |website=[[The Hill (newspaper)|The Hill]] |accessdate=20 December 2018}}</ref>

In February 2019, the astrophysicist Ethan Siegel wrote an article in ''Forbes'' titled "NASA's Idea For A Space Station In Lunar Orbit Takes Humanity Nowhere". Siegel stated that "Orbiting the Moon represents barely incremental progress; the only scientific 'advantages' to being in lunar orbit as opposed to low-Earth orbit are twofold: 1. You're outside of the Van Allen belts. 2. You're closer to the lunar surface," reducing the time delay. His final opinion was that the Lunar Gateway is "a great way to spend a great deal of money, advancing science and humanity in no appreciable way."<ref>{{cite web |last1=Siegel |first1=Ethan |title=NASA's Idea For A Space Station In Lunar Orbit Takes Humanity Nowhere |url=https://www.forbes.com/sites/startswithabang/2017/05/18/nasas-idea-for-a-space-station-in-lunar-orbit-takes-humanity-nowhere/#221e7593d145 |website=[[Forbes]] |accessdate=15 February 2019}}</ref>

==See also==

* [[Artemis program]]
* [[Lunar outpost (NASA)]]
* [[Commercial Resupply Services]]
* [[Deep Space Transport]]
* [[Deep Space Habitat]]
* [[Exploration Gateway Platform]]
* [[International Space Station]]
* [[Lunar Orbital Station]], a proposed Russian space station
* [[Next Space Technologies for Exploration Partnerships]]
* [[Orbital Piloted Assembly and Experiment Complex]]
* [[Project Prometheus]]

==References==
{{Reflist |30em}}

==External links==
* [https://www.nasa.gov/feature/deep-space-gateway-to-open-opportunities-for-distant-destinations Deep Space Gateway to Open Opportunities for Distant Destinations] - NASA Journey to Mars
* [http://www.russianspaceweb.com/imp.html First human outpost near the Moon] – RussianSpaceWeb page about the Lunar Orbital Platform – Gateway
*[http://www.russianspaceweb.com/imp-2017.html History of the Gateway planning]

{{Space stations}}
{{Moon spacecraft}}
{{Artemis program}}
{{Future spaceflights}}

[[Category:Lunar Orbital Platform-Gateway| ]]
[[Category:Crewed spacecraft]]
[[Category:Proposed space stations]]
[[Category:NASA programs]]
[[Category:Artemis program]]
[[Category:NASA space stations]]

[[Category:Deep Space Habitat]]
[[Category:Missions to the Moon]]
[[Category:Spacecraft using halo orbits]]
[[Category:Joint ventures]]
[[Category:2020s in spaceflight]]

Soyuz-2-1v

2019-07-11T16:26:55Z

Blastr42: /* Operational history */

{{distinguish|Soyuz-2.1a|Soyuz-2.1b}}
{{Infobox Rocket
|name = Soyuz-2-1v
|image = Воздушно-космические силы провели успешный пуск ракеты-носителя «Союз-2» с космодрома Плесецк 04.jpg
|imsize = 180px
|caption = Launch of an Soyuz-2-1v carrying Kosmos 2525 military satellite on 28 March 2018
|function = Light carrier rocket
|manufacturer = [[Progress State Research and Production Rocket Space Center|TsSKB Progress]]
|country-origin = Russia
|height = {{convert|44|m}}
|diameter = {{convert|3|m}}
|mass = {{convert|158000|kg}}
|stages = 2
|capacities =
{{Infobox Rocket/Payload
|location = 200km x 51.8° [[Low Earth orbit|LEO]]
|kilos = {{convert|2850|kg}}
}}
{{Infobox Rocket/Payload
|location = 200km x 62.8° [[Low Earth orbit|LEO]]
|kilos = {{convert|2800|kg}}
}}
|family = [[R-7 (rocket family)|R-7]]/[[Soyuz (rocket family)|Soyuz]]/[[Soyuz-2 (rocket)|2]]
|comparable = [[Long March 2C]] [[PSLV]]
|status = Active
|sites = [[Baikonur Cosmodrome|Baikonur]] Sites [[Gagarin's Start|1/5]] & [[Baikonur Cosmodrome Site 31|31/6]] [[Plesetsk Cosmodrome|Plesetsk]] [[Plesetsk Cosmodrome Site 43|Site 43]] [[Vostochny Cosmodrome|Vostochny]]
|launches = 5
|success = 4
|fail = 
|partial = 1
|first = 28 December 2013
|last = 10 July 2019
}}
The '''Soyuz-2-1v''' ({{lang-ru|'''Союз 2.1в'''}}, ''Union 2.1v''), [[GRAU index]] '''14A15''',<ref>{{cite web |publisher= [[Plesetsk Cosmodrome|Plesetsk]] | accessdate= 30 December 2013 |url=http://www.plesetzk.ru/rn/rus |title=Rus/Souyz-2 launch vehicle | language = Russian}}</ref> known earlier in development as the '''Soyuz-1''' ({{lang-ru|'''Союз 1'''}}, ''Union 1''), is a [[Russian Federation|Russian]] [[expendable launch system|expendable]] [[launch vehicle|carrier rocket]]. It was derived from the [[Soyuz-2 (rocket)|Soyuz-2.1b]], and is a member of the [[R-7 (rocket family)|R-7 family]] of rockets. It is built by [[Progress State Research and Production Rocket Space Center|TsSKB Progress]], at [[Samara, Russia|Samara]] in the [[Russian Federation]]. Launches are conducted from existing facilities at the [[Plesetsk Cosmodrome]] in Northwest Russia, with pads also available at the [[Baikonur Cosmodrome]] in [[Kazakhstan]],<ref name="Samara">{{cite web|url=http://www.samspace.ru/ENG/RN/souz_1.htm|title="Soyuz-1" middle class launch vehicle|publisher=Samara Space Centre|accessdate=11 April 2009|deadurl=yes|archiveurl=https://web.archive.org/web/20090419163533/http://www.samspace.ru/ENG/RN/souz_1.htm|archivedate=19 April 2009|df=dmy-all}}</ref> and new facilities at the [[Vostochny Cosmodrome]] in Eastern Russia.<ref>{{cite web|url=http://rbth.co.uk/science_and_tech/2013/07/24/vostochny_cosmodrome_clears_the_way_to_deep_space_28345.html | publisher = Russia Beyond The Headlines | accessdate = 30 December 2013 | title = Vostochny Cosmodrome clears the way to deep space | date = 24 July 2013 | first = Alexander | last = Peslyak}}</ref>

==Vehicle==
The Soyuz-2-1v represents a major departure from earlier [[Soyuz (rocket family)|Soyuz]] rockets. Unlike the Soyuz-2-1b upon which it is based, it does away with the four boosters used on all other [[R-7 (rocket family)|R-7]] vehicles. The first stage of the Soyuz-2-1v is a heavily modified derivative of the Soyuz-2 first stage, with a single-chamber [[NK-33]] engine replacing the four-chamber [[RD-117]] used on previous rockets along with structural modifications to the stage and lower tanking. Since the NK-33 is fixed, the [[RD-0110R]] engine is used to supply thrust vector control. It also supplies an extra {{convert|230.5|kN|lbf}}<ref name=kbkha-rd0110r /> of thrust and heats the pressurization gases.<ref name=kbkha-rd0110r>{{cite web |url=http://www.kbkha.ru/?p=8&cat=8&prod=74 |title= Steering engine RD0110R (14D24). Carrier rocket "Soyuz-2-1v" |publisher=KBKhA |language=Russian |accessdate=1 June 2015}}</ref>

The [[NK-33]] engine, originally built for the [[N1 (rocket)|N1]] programme, offers increased performance over the RD-117; however, only a limited number of engines are available. Once the supply is exhausted, the NK-33 will be replaced by the [[RD-193]]. In April 2013, it was announced that the RD-193 engine had completed testing. The RD-193 is a lighter and shorter engine based on the [[Angara (rocket family)|Angara]]'s [[RD-191]], which is itself a derivative of the [[Zenit (rocket family)|Zenit]]'s [[RD-170]].<ref>{{cite web|title=New engine for light rocket "Soyuz" prepare for mass production at the end of the year|url=http://www.novosti-kosmonavtiki.ru/news/7229/|publisher=Новости космонавтики|accessdate=8 April 2013|language=Russian}}</ref>

The second stage of the Soyuz-2-1v is the same as the third stage of the Soyuz-2-1b;<ref>{{cite web |url=http://www.russianspaceweb.com/soyuz1_lv_origin.html |title=Origin of the Soyuz-1 project |first=Anatoly |last=Zak |work=RussianSpaceWeb |accessdate=30 December 2013}}</ref> powered by an [[RD-0124]] engine. For most missions a [[Volga (rocket stage)|Volga]] upper stage will be used to manoeuvre the payload from an initial parking orbit to its final destination. The Volga is derived from the propulsion system of the [[Yantar (satellite)|Yantar]] reconnaissance satellite, and was developed as a lighter and cheaper alternative to the [[Fregat]].

The Soyuz-2-1v was designed as a light-class carrier rocket, and has a payload capacity of {{convert|2850|kg}} to a {{convert|200|km|sing=on}} circular [[low Earth orbit]] with an [[inclination]] of 56.8° from Baikonur, and {{convert|2800|kg}} to a 200 kilometre orbit at 62.8° from Plesetsk.<ref name="Samara"/>

==Operational history==
In 2009, the maiden flight of the Soyuz-2-1v was announced as being scheduled for 2010, with this later being delayed to 2011 and then 2012 by development delays and payload availability. By June 2011 it was scheduled to occur at the end of 2012. During a test firing of a first stage prototype in August 2012, a test stand software malfunction resulted in damage to the stand and prototype, delaying the static testing programme.<ref>{{cite web |url=http://www.russianspaceweb.com/soyuz1_lv_development.html |title=Development of Soyuz-1 |first=Anatoly |last=Zak |work=RussianSpaceWeb |accessdate=28 December 2013}}</ref>

The test was re-attempted in May 2013, and was declared successful despite the burn lasting 52 seconds shorter than had been expected. With this complete, the launch was scheduled for September 2013. It subsequently slipped to November and then December.<ref name="s101">{{cite web|url=http://www.spaceflight101.com/soyuz-2-1v.html|title=Soyuz 2-1v|publisher=Spaceflight 101|accessdate=28 December 2013}}</ref>

The maiden flight – which made use of a [[Volga (rocket stage)|Volga]] upper stage – carried the [[Aist 1]] microsatellite and a pair of [[SKRL-756]] calibration spheres. Ahead of the launch, the rocket was rolled out to [[Plesetsk Cosmodrome Site 43|Site 43/4]] at the [[Plesetsk Cosmodrome]] on 18 December 2013 with the launch scheduled for 23 December.<ref name="s101"/>

The launch was delayed beyond 23 December by problems found during late testing at the pad. An attempt to launch was made on 25 December, but it was scrubbed around ten minutes before the liftoff, which had been scheduled for 14:00 UTC. Despite reports that the launch could not take place before the end of the year, it was rescheduled for 10:30 UTC on 28 December.<ref>{{cite web|url=http://www.russianspaceweb.com/soyuz1_lv_aist.html|title=Soyuz-2-1v lifts off successfully|first=Anatoly|last=Zak|work=RussianSpaceWeb|accessdate=28 December 2013}}</ref> A further last-minute delay pushed the liftoff back to 12:30 UTC (16:30 local time), at which time the launch took place successfully.<ref>{{cite web|url=http://en.ria.ru/russia/20131228/186021089/After-Series-of-Delays-Russia-Launches-New-Soyuz-Rocket.html|title=After Series of Delays, Russia Launches New Soyuz Rocket|publisher=RIA Novosti|date=28 December 2013|accessdate=28 December 2013}}</ref> Spacecraft separation occurred 100 minutes later, at 14:10 UTC.<ref>{{cite web|url=http://www.nasaspaceflight.com/2013/12/russia-debut-soyuz-2-1v-plesetsk/|title= Russia conducts debut launch of Soyuz-2-1v|author=Nathaniel Downes and Chris Bergin|publisher=NASASpaceflight.com|accessdate=28 December 2013}}</ref>

The second launch of the vehicle on December 5, 2015 carried two payloads Kanopus-ST and KYuA-1, while the Kanopus-ST failed to separate from the final stage.<ref name="reuters">{{cite web|url=http://in.reuters.com/article/press-digest-russia-dec-idINL8N13W0U620151207|author=Reuters Editorial|title=PRESS DIGEST - RUSSIA - Dec 7|website=Reuters|accessdate=10 December 2017}}</ref><ref name="spaceflightinsider">{{cite web|url=http://www.spaceflightinsider.com/missions/defense/russia-successfully-launches-kanopus-st-satellite-into-orbit/|title=Russian Soyuz-2.1v launch a partial failure|website=SpaceFlight Insider|accessdate=10 December 2017}}</ref>

An unannounced launch carried a secret military payload on June 23, 2017.<ref>{{cite web |url=https://spaceflightnow.com/2017/06/23/secret-russian-satellite-launched-from-plesetsk-cosmodrome/ |title=Secret Russian satellite launched from Plesetsk Cosmodrome |last=Clark |first=Stephen |date=23 June 2017 |access-date=24 June 2017 }}</ref>

The next flight was on 29 March 2018.<ref>{{cite web |url=http://www.russianspaceweb.com/emka.html |title=Soyuz-2-1v launches a military payload |last=Zak |first=Anatoly |date=29 March 2018 |access-date=29 March 2018 }}</ref>

The latest flight took place on 7 July 2019 carrying four military satellites, Kosmos-2535, Kosmos-2536, Kosmos-2537 and Kosmos-2538, from the [[Plesetsk Cosmodrome]].<ref>{{cite web|url=https://www.nasaspaceflight.com/2019/07/soyuz-2-1v-surprise-military-launch/|title=Soyuz 2-1v conduts surprise military launch|publisher=Graham W|date=10 July 2019|access date=11 July 2019}}</ref>

== Photogallery from Paris Air Show 2011 ==
Russia exhibited a model of the Soyuz-2-1v during the [[2011 Paris Air Show]] at [[Le Bourget]].
<gallery>
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take1.JPG|General view of the rocket
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take3.jpg|Second stage view
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take2.jpg|Detailed view of the payload section
</gallery>

==References==
{{reflist|30em}}

{{Expendable launch systems}}
{{Russian launch vehicles}}
{{R-7 rockets}}

{{Use British English|date=January 2014}}
{{Use dmy dates|date=January 2014}}

[[Category:R-7 (rocket family)]]
[[Category:Space launch vehicles of Russia]]
[[Category:2013 in spaceflight]]
[[Category:Vehicles introduced in 2013]]

[[ru:Союз-1 (ракета-носитель)]]

OmegA

2019-03-08T18:29:12Z

Blastr42: /* External links */

{{redirect|OmegA|other uses|omega (disambiguation)}}
{{Infobox rocket
|name = Omega
|manufacturer = [[Northrop Grumman]]
|country-origin = United States
|height = {{convert|59.84|m|ft|sp=us}}
|diameter = {{convert|3.71|m|ft|sp=us}} first stage {{convert|5.25|m|ft|sp=us}} upper stage
|mass =
|stages = 3
|capacities =
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="oatk20180221">{{cite web|title=Orbital ATK Next Generation Launch System Completes Major Milestones|url=https://www.orbitalatk.com/news-room/insideOA/NGL/default.aspx|website=Orbital ATK|accessdate=17 April 2018|date=21 February 2018}}</ref>
}}
{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="oatk20180221" />{{dead|date=December 2018}}
}}
|family = [[Shuttle-Derived Launch Vehicle]]
|derivatives = 
|comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
|status = Under development
|sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]]
|launches = 0
|success = 0
|fail = 0
|partial = 0
|first= 2021 (projected)
|stagedata =
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name = [[Graphite-Epoxy Motor|GEM-63 or GEM-63XL]]
|number = 0 to 6
|diameter = {{convert|63|in|m|order=flip|sp=us|abbr=on}}
|solid = yes
|total = 
|SI = {{convert|279.3|isp}}
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = First
|engines = [[Castor (rocket stage)|Castor]] 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Second
|engines = [[Castor (rocket stage)|Castor]] 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Third
|engines = 2 × [[RL-10|RL-10C-5-1]]
|thrust = {{convert|22890|lbf|kN|order=flip}}
|SI = ~450 seconds (vacuum)
|burntime = unknown
|fuel = [[LOX]]/[[LH2]]
}}
}}
'''Omega''', stylized as "'''OmegA'''", is a [[launch vehicle]] in development by [[Northrop Grumman]] as an [[National Security Space Launch|NSSL]] replacement program intended for national security and commercial satellites.<ref>{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have used a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne]]<ref>{{Cite news |last1=Erwin |first1=Sandra |last2=Berger |first2=Brian |url=http://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/ |title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket |date=16 April 2018 |work=SpaceNews.com |access-date=18 April 2018 |language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spaceflightnow.com/2016/05/27/details-of-orbital-atks-proposed-heavy-launcher-revealed/|title=Details of Orbital ATK’s proposed heavy launcher revealed |publisher= Spaceflight Now|first=Stephen|last=Clark|date=27 May 2016}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development was to start once the Air Force reached a funding decision. In October 2018, the Air Force announced that Northrop Grumman was awarded $792 million for initial development of the Omega launch vehicle.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

==History==
[[File: Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, [[Orbital ATK]] (now Northrop Grumman Innovation Systems) was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5-6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher is planned to take place between late 2017 and early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{update after|2017|12}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). The rocket would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor.<ref>{{cite web|title=Orbital ATK Twitter|url=https://twitter.com/OrbitalATK/status/986030002213879808|website=Twitter|accessdate=17 April 2018|date=17 April 2018}}</ref> The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}}.<ref name="oatk20180221" />{{dead|date=December 2018}}

In October 2018, OmegA was awarded a Launch Services Agreement worth $791,601,015 to design, build and launch the first Omega rockets.<ref name=SpaceNews-20181010>{{cite web|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force Awards Launch Vehicle Development Contracts to Blue Origin Northrop Grummand ULA|publisher=Space News|date=10 October 2018 |author=Sandra Erwin}}</ref>

==Multiple configurations==
The rocket will have two basic configurations, an intermediate and a heavy launch. The intermediate version will have a two segment, shuttle derived [[solid rocket booster]] (SRB) first stage with a liquid hydrogen fueled upper stage. The heavy configuration will be a three stage vehicle, including a 4-segment SRB first stage, a single segment SRB second stage, and the same cryogenic upper stage. Additional versions are projected to add additional SRBs as side boosters. The [[Shuttle-Derived Launch Vehicle|SDLV]] SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }} </ref>

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

==References==
{{Reflist|2}}

==External links==
*[http://www.northropgrumman.com/Capabilities/Omega/Pages/default.aspx OmegA official web site]

{{S-start}}
{{Succession box
| title = Single-stick SRB-based [[Shuttle-Derived Launch Vehicle|SDLV]]
| years = 2016-
| before = [[Liberty (rocket)|Liberty]]
| after = N/A CURRENT
}}
{{S-end}}

{{US launch systems}}
{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

OmegA

2019-03-08T18:27:01Z

Blastr42: /* History */

{{redirect|OmegA|other uses|omega (disambiguation)}}
{{Infobox rocket
|name = Omega
|manufacturer = [[Northrop Grumman]]
|country-origin = United States
|height = {{convert|59.84|m|ft|sp=us}}
|diameter = {{convert|3.71|m|ft|sp=us}} first stage {{convert|5.25|m|ft|sp=us}} upper stage
|mass =
|stages = 3
|capacities =
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="oatk20180221">{{cite web|title=Orbital ATK Next Generation Launch System Completes Major Milestones|url=https://www.orbitalatk.com/news-room/insideOA/NGL/default.aspx|website=Orbital ATK|accessdate=17 April 2018|date=21 February 2018}}</ref>
}}
{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="oatk20180221" />{{dead|date=December 2018}}
}}
|family = [[Shuttle-Derived Launch Vehicle]]
|derivatives = 
|comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
|status = Under development
|sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]]
|launches = 0
|success = 0
|fail = 0
|partial = 0
|first= 2021 (projected)
|stagedata =
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name = [[Graphite-Epoxy Motor|GEM-63 or GEM-63XL]]
|number = 0 to 6
|diameter = {{convert|63|in|m|order=flip|sp=us|abbr=on}}
|solid = yes
|total = 
|SI = {{convert|279.3|isp}}
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = First
|engines = [[Castor (rocket stage)|Castor]] 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Second
|engines = [[Castor (rocket stage)|Castor]] 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Third
|engines = 2 × [[RL-10|RL-10C-5-1]]
|thrust = {{convert|22890|lbf|kN|order=flip}}
|SI = ~450 seconds (vacuum)
|burntime = unknown
|fuel = [[LOX]]/[[LH2]]
}}
}}
'''Omega''', stylized as "'''OmegA'''", is a [[launch vehicle]] in development by [[Northrop Grumman]] as an [[National Security Space Launch|NSSL]] replacement program intended for national security and commercial satellites.<ref>{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have used a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne]]<ref>{{Cite news |last1=Erwin |first1=Sandra |last2=Berger |first2=Brian |url=http://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/ |title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket |date=16 April 2018 |work=SpaceNews.com |access-date=18 April 2018 |language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spaceflightnow.com/2016/05/27/details-of-orbital-atks-proposed-heavy-launcher-revealed/|title=Details of Orbital ATK’s proposed heavy launcher revealed |publisher= Spaceflight Now|first=Stephen|last=Clark|date=27 May 2016}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development was to start once the Air Force reached a funding decision. In October 2018, the Air Force announced that Northrop Grumman was awarded $792 million for initial development of the Omega launch vehicle.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

==History==
[[File: Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, [[Orbital ATK]] (now Northrop Grumman Innovation Systems) was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5-6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher is planned to take place between late 2017 and early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{update after|2017|12}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). The rocket would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor.<ref>{{cite web|title=Orbital ATK Twitter|url=https://twitter.com/OrbitalATK/status/986030002213879808|website=Twitter|accessdate=17 April 2018|date=17 April 2018}}</ref> The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}}.<ref name="oatk20180221" />{{dead|date=December 2018}}

In October 2018, OmegA was awarded a Launch Services Agreement worth $791,601,015 to design, build and launch the first Omega rockets.<ref name=SpaceNews-20181010>{{cite web|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force Awards Launch Vehicle Development Contracts to Blue Origin Northrop Grummand ULA|publisher=Space News|date=10 October 2018 |author=Sandra Erwin}}</ref>

==Multiple configurations==
The rocket will have two basic configurations, an intermediate and a heavy launch. The intermediate version will have a two segment, shuttle derived [[solid rocket booster]] (SRB) first stage with a liquid hydrogen fueled upper stage. The heavy configuration will be a three stage vehicle, including a 4-segment SRB first stage, a single segment SRB second stage, and the same cryogenic upper stage. Additional versions are projected to add additional SRBs as side boosters. The [[Shuttle-Derived Launch Vehicle|SDLV]] SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }} </ref>

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

==References==
{{Reflist|2}}

==External links==
*[https://www.orbitalatk.com/flight-systems/space-launch-vehicles/OmegA/default.aspx OmegA official web site]

{{S-start}}
{{Succession box
| title = Single-stick SRB-based [[Shuttle-Derived Launch Vehicle|SDLV]]
| years = 2016-
| before = [[Liberty (rocket)|Liberty]]
| after = N/A CURRENT
}}
{{S-end}}

{{US launch systems}}
{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

Shuttle-derived vehicle

2019-01-07T23:51:52Z

Blastr42: /* Next Generation Launcher */

[[File:Saturn V-Shuttle-Ares I-Ares V-Ares IV-SLS Block I comparison.png|thumb|400px|Saturn V, Shuttle, Ares I, Ares V, Ares IV, and SLS Block I]]
'''Shuttle-Derived Launch Vehicle''', or simply '''Shuttle-Derived Vehicle (SDV)''', is a term describing one of a wide array of concepts that have been developed for creating space [[launch vehicle]]s from the components, technology and infrastructure of the [[Space Shuttle program]]. SDVs have also been part of NASA's plans several times in the past. In the late 1980s and early 1990s, NASA formally studied a cargo-only vehicle, [[Shuttle-C]], that would have supplemented the crewed Space Shuttle in orbiting payloads.

In 2005, NASA decided to develop the [[Ares I]] and [[Ares V]] launch vehicles, based in part on highly modified Shuttle components to replace the [[Space Shuttle]], and enable exploration of the [[Moon]] and [[Mars]].<ref name=ares>{{cite web | date = June 30, 2006 | url = http://www.nasa.gov/mission_pages/exploration/spacecraft/ares_naming.html | title = Ares: NASA's New Rockets Get Names | publisher = NASA | accessdate = November 22, 2006}}</ref><ref>{{cite news|first=Tariq |last=Malik |url=http://space.com/news/060630_ares_rockets.html |title=NASA Names Rockets for Moon and Mars Missions |publisher=Space.com |date=30 June 2006 |accessdate=2006-11-22}}</ref> The agency also studied a third such vehicle, the [[Ares IV]]. As of April 2011, NASA's replacement vehicle for the Space Shuttle is an SDV, the [[Space Launch System]] and multiple commercial vehicles. Over the course of the 2010 two different commercial vehicles were developed that use man-rated heavy lift launcher. In the meantime NASA has continued to use the Russian [[Soyuz (rocket family)|Soyuz]], which it also used during the Shuttle program as part of the International Space Station program.

== Concepts ==
{{See also|Magnum (rocket)}}
[[Image:In-Line SDLV 1978.jpg|thumb|right|1978 image of a Morton Thiokol-proposed In-Line Shuttle Derived Launch Vehicle. ]]

SDV concepts were proposed even before the Shuttle itself began flying. Proposed SDV concepts have included:
* Replacing the winged [[Space Shuttle Orbiter]] with an uncrewed, expendable cargo pod ("side-mount style" SDV)
* Removing the Orbiter and mounting an upper stage and payload atop the [[Space Shuttle external tank]] ("inline-style" SDV)
* Adding a large cargo container to the rear of the external tank, allowing launches of bulky materials (Aft Cargo Carrier)
* Replacing the [[Space Shuttle Solid Rocket Booster]]s (SRBs) with liquid rockets, including recoverable winged "flyback" boosters
* Creating vehicles from one or more Space Shuttle Solid Rocket Boosters, usually with some kind of an upper stage
* Removing the wings of an Orbiter at the end of its useful life, permanently attaching it to a Space Shuttle external tank, and launching the combination as a space station

Several such concepts are of particular note:

=== Shuttle-C ===
{{main|Shuttle-C}}
[[File:Shuttle-c launch painting.jpg|thumb|right|Shuttle-C art]]
Beginning in 1987, NASA actively pursued development of a vehicle called the Shuttle-C, an uncrewed cargo-only launch vehicle. Shuttle-C would have replaced the winged Space Shuttle Orbiter with an expendable cargo module. The module would have no wings, would not carry crew, and would not be recovered. It was expected to carry up to {{convert|150000|lb|kg}} of payload to low-Earth orbit, compared to the Shuttle's nominal maximum of {{convert|65000|lb|kg}}. Budget pressures, caused in large part by the [[Space Station Freedom]] project, resulted in the official cancellation of Shuttle-C in 1990.

=== National Launch System ===
{{main|National Launch System}}

The National Launch System was a study authorized in 1991 by President [[George H. W. Bush]] to outline alternatives to the [[Space Shuttle]] for access to Earth Orbit. The largest of three proposed vehicles was designated NLS-1 and used for its core stage a modified [[Space Shuttle]] [[External Tank]] with four Space Transportation Main Engines (STMEs) attached to the bottom of the tank. A payload or [[Multistage rocket|second stage]] would fit atop the core stage, and two detachable [[Space Shuttle Solid Rocket Booster|Solid Rocket Boosters]] would be mounted on the sides of the core stage. Larger rockets than NLS-1 were contemplated, using multiples of the NLS-1 core stage.

=== DIRECT / Jupiter ===
{{main|DIRECT|Jupiter (rocket family)}}
[[File:Jupiter Family.jpg|thumb|Some envisioned Jupiter configurations, including crew and cargo variants]]

A recent proposal put forward as alternative to the NASA Ares vehicles is the "Direct Shuttle Derivative" or DIRECT architecture (unrelated to the "Mars Direct" plan), made by a grassroots group of engineers and other spaceflight enthusiasts. As of May 2009, DIRECT revolves a notional series of vehicles, dubbed "Jupiter", that would use an [[Space Shuttle external tank|external tank]] (ET) derived core stage powered by three or four [[Space Shuttle Main Engine]]s (SSMEs), plus a pair of standard four-segment SRBs. All versions of Jupiter would use this "common core"; larger variants would include an upper stage.

DIRECT's proponents, which the group says includes dozens of NASA and industry personnel working anonymously, argue that development costs of this vehicle would be significantly lower than those for the Ares I / Ares V because of Jupiter's greater commonality with the existing Space Shuttle and its proven, human-rated systems. Further, because the same common core design would be used for both crew and cargo launches, savings would be realized over the dissimilar Ares I and Ares V vehicles through economies of scale, streamlined production and processing, and the like. The DIRECT Team claims that two Jupiter launches would be capable of exceeding NASA's delivered payload mass targets for an Ares I / Ares V lunar mission.

The group presented its concept to the [[Review of United States Human Space Flight Plans Committee]] at a public hearing on 17 June 2009 in Washington, D.C.

=== NASA Side-Mount Vehicle ===
{{main|Shuttle-Derived Heavy Lift Launch Vehicle}}
[[File:Nasansc.JPG|thumb|right|upright=1.4|Artist impression of the Shuttle-Derived HLV concept]]
In June 2009 at the same public hearing of the [[Review of United States Human Space Flight Plans Committee]], Shuttle Program Manager John Shannon unveiled a preliminary concept for a new "side-mount" variant SDV. NASA had begun studying this as an alternate for the [[Constellation program]]. <ref>Borenstein, Seth for Associated Press. [https://www.usatoday.com/tech/science/space/2009-06-30-nasa-moon_N.htm "NASA manager pitches a cheaper return-to-moon plan"]. USA Today, June 30, 2009.</ref> This concept would be somewhat similar to the Shuttle-C, but with the Shuttle Orbiter replaced by a keel and boattail structure permanently affixed to the ET (as opposed to the detachable cargo-carrier on Shuttle-C). Three SSMEs would be mounted in the boattail, essentially a simplified Orbiter boattail, and a large expendable fairing would encapsulate the payload. The entire vehicle, including SSMEs, would be discarded after launch. Shannon presented the concept for both cargo-only operation, and crewed missions using the Orion spacecraft and its [[launch escape system]].<ref>{{cite news|first=Irene |last=Klotz |url=http://www.msnbc.msn.com/id/31532912/ns/technology_and_science-space |title=NASA readies Plan B for moon rockets |publisher=msnbc.com |date=24 June 2009 |accessdate=2009-06-30}}</ref><ref>[http://www.nasa.gov/pdf/361842main_15%20-%20Augustine%20Sidemount%20Final.pdf "Shuttle-Derived Heavy Lift Launch Vehicle"]. NASA, June 17, 2009.</ref> While requiring far less development than the Ares vehicles, the basic configuration of the vehicle would in a 2-launch lunar architecture be less capable than the currently envisioned Ares I and Ares V mission scenario.

=== Mars Direct ===
{{main|Mars Direct}}

As part of the Mars Direct plan, [[Mars]] exploration advocate [[Robert Zubrin]] and other baselined an "inline" SDV concept developed by engineers at NASA and Martin Marietta. The rocket consisted of a large upper stage and payload shroud mounted on top of the Space Shuttle external tank, and the Orbiter replaced by a simple engine pod. The rocket would launch crews and vehicles directly to Mars. The term "Mars Direct" reflected the idea of launching crews and habitats directly to Mars, without assembly or significant loiter in low Earth orbit. NASA's planned Ares V vehicle would superficially resemble this vehicle due to its "inline" setup, although the Mars Direct Ares used side-mounted Space Shuttle Main Engines and a core with the Shuttle External Tank's diameter for greater commonality with Space Shuttle infrastructure.

===Vision for Space Exploration===
{{main|Vision for Space Exploration}}
In 2005, NASA decided to pursue the design and construction of two new launchers, both based on technology and infrastructure developed for the US [[Space Shuttle program]]. These launchers would replace the Space Shuttle and supply the launch services necessary to fulfill the Vision for Space Exploration. NASA has given the name "[[Project Constellation]]"<ref>{{cite news |first=Brian |last=Berger |url=http://space.com/news/060120_cev_overhaul.html |title=CEV Makeover: NASA Overhauls Plans for New Spaceship |publisher=Space.com |date=20 January 2006 |accessdate=2006-11-22}}</ref> for the manned Crew Launch Vehicle project.

====Ares I====
{{main|Ares I}}
[[File:Ares I-X launch 08.jpg|thumb|right|[[Ares I-X]] test launch in 2009]]
The [[Ares I]], to be used for crew launch, was to use as its first stage a [[solid rocket]] derived from the [[Space Shuttle Solid Rocket Booster]] (SRB). Whereas the Shuttle SRBs used four segments of solid propellant, the Ares I first stage would have used five. The shape of the central bore of each propellant segment was going to be modified to produce a faster burn.<ref>{{cite news|first= |last= |url=http://www.flightglobal.com/Articles/2007/01/16/Navigation/200/211501/More+powerful+vehicle+'no+threat'+to+launcher.html |title=More Powerful Vehicle 'No Threat' To Launcher |publisher=flightglobal.com |date=16 January 2007 |accessdate=2007-01-26}}</ref> The Ares I would have been topped by a new second stage burning liquid oxygen and liquid hydrogen.

====Ares V====
{{main|Ares V}}

The unmanned Ares V vehicle, to be used to loft equipment for [[lunar sortie]] or [[lunar outpost]] flights into orbit to be met by human crews launched by the Ares I, superficially resembles many of the earlier proposed "inline" SDV concepts. NASA also has proposals of using the Ares V as the main booster to launch the manned [[Orion Asteroid Mission]] to an orbiting [[Near-Earth Asteroid]]. It consists of a cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) center stage flanked by two modified SRBs, topped by a new second stage based on the [[S-IVB]] stage of the [[Saturn V]] rocket. Previous "inline" SDV concepts, however, envisioned extensive use of Shuttle components such as the existing External Tank, or a "stretched" version thereof, as well as the Shuttle's existing main engines. The Ares V will use stretched five or "five-point-five"-segment versions of the SRBs; a new, larger tank using Shuttle External Tank construction and insulation technology; and newer, cheaper expendable rocket engines (the [[Pratt & Whitney Rocketdyne]] [[RS-68]] engine, identical to those used on the [[Delta IV]] [[Evolved Expendable Launch Vehicle|EELV]]) located at the base of the new tank.

====Ares IV====
[[File:NASA-Ares-logo.svg|thumb|Ares logo]]
NASA briefly studied a third, crew-capable, launch vehicle concept, called [[Ares V#Ares_IV|Ares IV]], which would use the Ares V first stage core and side-mounted SRBs, but with the planned Ares I second stage atop that to carry the Orion crew vehicle. Advantages over the Ares I would probably include reduced development cost and time, common launch pad infrastructure and providing more than adequate lift for the Orion, while disadvantages would include increased per-launch cost over the use of a single SRB for the first stage. According to NASA, potential uses of the Ares IV would have included sending the Orion spacecraft on early "shakeout" missions into lunar orbit only, as well as testing high-speed [[Skip reentry|"skip reentries"]] in which the capsule would skip in the Earth's atmosphere before landing, rather than making a relatively direct descent.<ref>{{cite news|first=Brian |last=Berger |url=http://space.com/news/070126_ares_moon.html |title=NASA Studies Early Moon Shot for New Space Capsule |publisher=Space.com |date=26 January 2007 |accessdate=2007-01-26}}</ref>

====Ares V Lite====
[[Ares IV#Ares IV|Ares IV]] was an alternative launch vehicle for NASA's Constellation program suggested by the [[Review of United States Human Space Flight Plans Committee|Augustine Commission]]. [[Ares V Lite#Ares V Lite|Ares V Lite]] was a scaled down Ares V.<ref>Coppinger, Rob. [http://www.flightglobal.com/articles/2009/08/11/330800/will-constellation-live-on.html "Will Constellation live on?"]. Flight International, August 11, 2009.</ref><ref>Madrigal, Alexis. [https://www.wired.com/wiredscience/2009/10/augustine-final-report/ "Human Spaceflight Ball in Obama’s Court"]. Wired, October 22, 2009.</ref> It would use five [[RS-68]] engines and two five-segment SRBs and have a low Earth orbit payload of approximately 140 metric tons (309,000 lb).<ref name=HSF_review_Lite/> If chosen, Ares V Lite would replace the Ares V and [[Ares I]] launchers. One Ares V Lite version would be a cargo lifter like Ares V and the second version would carry astronauts in the Orion spacecraft.<ref name=HSF_review_Lite>Augustine Committee 2009, pp. 38, 64-67, 80.</ref>

===Space Launch System===
{{main|Space Launch System}}
[[File:Orange tank SLS - Post-CDR.jpg|thumb|Concept art for SLS, 2015]]
The [[NASA Authorization Act of 2010]] envisions the transformation of the [[Ares I]] and [[Ares V]] vehicle designs into a Heavy Lift Launch Vehicle, the Space Launch System, both for crew and cargo. It is to be upgraded over time with more powerful versions. The initial capability of the core elements, without an upper stage, should be for between 70 tons and 100 tons into [[low-Earth orbit|LEO]] in preparation for transit for [[beyond low-Earth orbit|missions beyond low-Earth orbit]]. With the addition of integrated upper [[Earth Departure Stage|Earth departure stage]] the total lift capability of the Space Launch System should be 130 tons or more.<ref>[http://thomas.loc.gov/cgi-bin/query/D?c111:3:./temp/~c111MS7qB3:: S.3729 -- National Aeronautics and Space Administration Authorization Act of 2010]</ref>

===Liberty===
{{main|Liberty (rocket)}}

A proposal put forth by [[Alliant Techsystems|ATK]] and [[Astrium]] was to use a five-segment version of the [[Space Shuttle Solid Rocket Booster]] as a first stage and a liquid-core first stage of an [[Ariane 5]] as the second stage of a proposed rocket named [[Liberty (rocket)|Liberty]]. Such a design would cut costs and development time by using already-proven technologies. Liberty would have been 90 meters in length with a projected capability of carrying 20 metric tonnes to [[low earth orbit]]. It was projected that this rocket would be flight-capable by 2013 and human-certified by 2015. Some of the potential crew vehicles were being developed with funds from the [[Commercial Crew Development|Commercial Crew Development program]].<ref>{{cite news| url=https://www.bbc.co.uk/news/science-environment-12394991 | work=BBC News | title=New rocket could lift astronauts | date=8 February 2011}}</ref> However, Liberty was not among the vehicles selected for funding announced on August 3, 2012 under the [[Commercial Crew Development#Commercial Crew integrated Capability|Commercial Crew Integrated Capacity]] program.<ref>{{cite web
|url = http://spacenews.com/civil/120803-boeing-spacex-sierra-ccicap.html
|title = Boeing, SpaceX and Sierra Nevada Win CCiCAP Awards
|accessdate = 2012-08-03
|publisher = Space News
|deadurl = yes
|archiveurl = https://archive.is/20130104234510/http://spacenews.com/civil/120803-boeing-spacex-sierra-ccicap.html
|archivedate = 2013-01-04
|df =
}}</ref>

===OmegA===
{{main|Omega (rocket)}}
In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527">{{cite web|url=https://spaceflightnow.com/2016/05/27/details-of-orbital-atks-proposed-heavy-launcher-revealed/|title=Details of Orbital ATK’s proposed heavy launcher revealed |publisher= Spaceflight Now|first=Stephen|last=Clark|date=27 May 2016}}</ref> Next Generational Launcher was to consist of Space Shuttle-derived solid stages with a cryogenic upper stage provide by [[Blue Origin]].<ref name=YahooFinance-20160524>{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL-10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor.<ref>{{cite web|title=Orbital ATK Twitter|url=https://twitter.com/OrbitalATK/status/986030002213879808|website=Twitter|accessdate=17 April 2018|date=17 April 2018}}</ref>

== References ==
{{Reflist}}

== Further reading ==
* {{cite book | first=Dennis R. | last=Jenkins | year=2002 | title=Space Shuttle: The History of the National Space Transportation System | publisher=Voyageur Press | location=Stillwater MN | isbn=0-9633974-5-1}}

== External links ==
{{portal|Spaceflight}}
* [https://web.archive.org/web/20100118201447/http://www.astronautix.com/lvfam/shuttle.htm Shuttle-Derived Vehicles]
* [https://web.archive.org/web/20060510134511/http://astronautix.com/lvs/shuttlec.htm Shuttle-C]
* [http://chapters.nss.org/ny/nyc/Shuttle-Derived%20Vehicles%20Modified.pdf SDV Presentation]
* [http://www.nasa.gov/mission_pages/exploration/spacecraft/index.html NASA Official Project Constellation Homepage]
* [http://www.nasa.gov/mission_pages/exploration/spacecraft/ares_naming.html NASA Official Ares Rocket Website]
* [http://space.com/news/060630_ares_rockets.html Ares Rocket at Space.com]
* [http://www.directlauncher.com The DIRECT Shuttle-derived launch vehicle proposal]
* [http://www.globalsecurity.org/space/systems/sdv-hllv.htm SDV Heavy Lift Launch Vehicles]
* [http://www.globalsecurity.org/space/systems/srb-x.htm SRB-X Launch Vehicle]
* [http://www.cnn.com/2006/TECH/space/03/03/cev.vs.apollo/index.html CEV vs Apollo]
* [http://img375.imageshack.us/img375/3017/clvcev7we.jpg Ares I-Crew Exploration Vehicle]
* [http://www.nasawatch.com/images/heft2.pdf HEFT about Heavy Lift Launch Vehicle]

{{Rocket families}}
{{Project Constellation}}
{{Space Shuttle}}
{{NASA navbox}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Space Shuttle program|Launch Vehicle]]
[[Category:Shuttle-derived space launch vehicles| ]]
[[Category:NASA space launch vehicles]]

Titan IV

2019-01-07T21:48:17Z

Blastr42: /* Features */

{{Infobox rocket
|image =Titan4B on Launch Complex 40.jpg
|caption = Launch of a Titan IVB launch vehicle. (USAF)
|name = Titan IV
|function = Heavy [[expendable launch system]]
|manufacturer = [[Lockheed Martin]]
|country-origin = United States
|cpl = $432 million (USD)
|cpl-year = 1999
|height = 50-62 m
|alt-height = 164-207 ft
|diameter = 3.05 m
|alt-diameter = 10 ft
|mass = 943,050 [[kilogram|kg]]
|alt-mass = 2,079,060 [[pound (mass)|lb]]
|stages = 3-5
|capacities =
{{Infobox rocket/Payload
|location=[[Low Earth orbit|LEO]]
|kilos = 21,680 kg
|pounds = 47,790 lb
}}
{{Infobox rocket/Payload
|location=[[Polar orbit|Polar LEO]]
|kilos = 17,600 kg
|pounds = 38,800 lb
}}
{{Infobox rocket/Payload
|location=[[Geosynchronous orbit|GSO]]
|kilos = 5,760 kg
|pounds = 12,690 lb
}}
{{Infobox rocket/Payload
|location=[[Heliocentric orbit|HCO]]
|kilos = 5,660 kg
|pounds = 12,470 lb
}}
|family = [[Titan (rocket family)|Titan]]
|comparable = [[Atlas V]], [[Delta IV Heavy]], [[Falcon Heavy]]
|status = Retired
|sites = [[Cape Canaveral Air Force Station Space Launch Complex 40|SLC-40]]/[[Cape Canaveral Air Force Station Space Launch Complex 41|41]], [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Vandenberg AFB Space Launch Complex 4|SLC-4E]], [[Vandenberg Air Force Base|Vandenberg AFB]]
|launches = 39<ref name=lm-ll>{{cite web |url=http://www.lockheedmartin.com/news/press_releases/2005/LOCKHEEDMARTINSLASTTITANIVSUCCESSFU.html |title=Lockheed Martin's Last Titan IV Successfully Delivers National Security Payload to Space |date=October 19, 2005 |deadurl=yes |archiveurl=https://web.archive.org/web/20080114010028/http://www.lockheedmartin.com/news/press_releases/2005/LOCKHEEDMARTINSLASTTITANIVSUCCESSFU.html |archivedate=January 14, 2008 |df= }}</ref> ('''IVA:''' 22, '''IVB:''' 17)
|success = 35 ('''IVA:''' 20, '''IVB:''' 15)
|fail = 4 ('''IVA:''' 2, '''IVB:''' 2)
|first='''IV-A:''' 14 June 1989 '''IV-B:''' 23 February 1997
|last='''IV-A:''' 12 August 1998 '''IV-B:''' 19 October 2005
|payloads = [[Lacrosse (satellite)|Lacrosse]] [[Defense Support Program|DSP]] [[Milstar]] [[Cassini-Huygens]]
|stagedata = 
{{Infobox rocket/Stage
|type = booster
|diff = IV-A
|name = [[UA120]]7
|number = 2
|engines = United Technologies UA1207
|thrust = 14.234 [[Newton (force)|MN]]
|alt-thrust = 3,200,000 [[Pounds-force|lbf]]
|SI = 272 seconds (2667 N·s/kg)
|burntime = 120 seconds
|fuel = [[Polybutadiene acrylonitrile|PBAN]]
}}
{{Infobox rocket/Stage
|type = booster
|diff = IV-B
|name = [[Solid Rocket Motor Upgrade |SRMU]]
|number = 2
|engines = [[Hercules Inc.|Hercules]] SRMU
|thrust = 15.12 MN
|alt-thrust = 3,400,000 lbf
|SI = 286 seconds (2805 N·s/kg)
|burntime = 140 seconds
|fuel = [[Hydroxyl-terminated polybutadiene|HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = First
|engines = [[LR87]]
|thrust = 2,440 kN
|alt-thrust = 548,000 lbf
|SI = 302 seconds (2962 N·s/kg)
|burntime = 164 seconds
|fuel = {{N2O4}} / [[Aerozine 50|A-50]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Second
|engines = 1 [[LR91]]
|thrust = 467 kN
|alt-thrust = 105,000 lbf
|SI = 316 seconds (3100 N·s/kg)
|burntime = 223 seconds
|fuel = {{N2O4}} / [[Aerozine 50|A-50]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Third
|diff = Optional
|name = [[Centaur (rocket stage)|Centaur-T]]
|engines = 2 [[RL10]]
|thrust = 147 kN
|alt-thrust =33,100 lbf
|SI = 444 seconds (4354 N·s/kg)
|burntime = 625 seconds
|fuel = [[LH2|LH2]]/[[LOX]]
}}
}}

The '''Titan IV''' family (including the IVA and IVB) of [[rocket]]s were used by the [[United States Air Force|U.S. Air Force]].<ref>{{cite web |url=http://www.af.mil/shared/media/document/AFD-070618-036.pdf
|title=Space and Missile System Center Mission and Organization
|work=Space and Missile Systems Center's History Office
|date= |format=PDF |accessdate=September 20, 2008}}</ref> They were [[rocket launch|launched]] from [[Cape Canaveral Air Force Station]], Florida,<ref>{{cite web|url=http://www.space.com/missionlaunches/launches/titan4_dsp_launch_010806.html
|title=Titan 4B and Cape Canaveral
|publisher=}}</ref> and [[Vandenberg Air Force Base]], California.<ref>{{cite web|url=http://spaceflightnow.com/titan/b28/index.html
|title=Spaceflight Now - Titan Launch Report - Titan 4 rocket expected to launch Lacrosse spy satellite
|publisher=}}</ref> At the time of its introduction, the Titan IV was the "largest unmanned space booster used by the Air Force."<ref>{{cite web |url=http://www.au.af.mil/au/awc/systems/dvic468.htm
|title=Titan IV
|publisher=USAF Air University |year=1996}}</ref>

As originally conceived in the mid-1980s, the Titan IV was only intended to complement the space shuttle and fly a mere ten times. However, the [[Challenger Disaster]] in 1986 caused a renewed dependence on [[expendable launch system]]s so that the program was significantly expanded. Under the original plan, the Titan IV would only be paired with Centaur stages and fly exclusively from LC-41 at Cape Canaveral.

The post-Challenger program also involved flying IUS ([[Inertial Upper Stage]]) or even no upper stages. LC-40 at the Cape was also converted for Titan IV. Even with the reduced schedule, almost forty Titan IVs were scheduled as of 1991 and a new, improved SRM ([[solid rocket motor]]) casing using lightweight composite materials was introduced.

The Titan IV was the last of the [[Titan (rocket family)|Titan family of rockets]]. It was retired in 2005 due to its high cost of operation. The final launch (B-30) from Cape Canaveral AFS occurred on April 29, 2005, and the final launch from Vandenberg AFB occurred on October 19, 2005.<ref>{{Cite APOD|title=The Last Titan |date=27 October 2005 |access-date=2008-09-20}}</ref>

[[Lockheed Martin Space Systems]] built the Titan IVs near Denver, Colorado, under contract to the [[Federal government of the United States|government]].<ref name=lm-ll />

==Features==
[[Image:LR91-AJ-11 rocket engine - Thrust chamber.jpg|thumb|left|[[LR91-AJ-11]] rocket engine]]
The Titan IV was developed to provide assured capability to launch [[Space Shuttle]]–class payloads for the Air Force. The Titan IV could be launched with no [[Multistage rocket|upper stage]], or either of two upper stages, the [[Inertial Upper Stage|IUS (Inertial Upper Stage)]], and the [[Centaur (rocket stage)|Centaur rocket]] upper stage.

The Titan IV was made up of two large [[solid-fuel rocket|solid-fuel rocket boosters]] and a two-stage liquid-fueled core. The two storable liquid fuel core stages used [[Aerozine 50]] fuel and [[nitrogen tetroxide]] oxidizer. These propellants are [[hypergolic]] (ignite on contact) and are liquids at room temperature, so no tank insulation is needed. This allows the launcher to be stored in a ready state for extended periods. Both propellants are extremely toxic.

The Titan IV could be launched from either coast: [[Cape Canaveral Air Force Station Space Launch Complex 40|SLC-40]] or [[Cape Canaveral Air Force Station Space Launch Complex 41|41]] at Cape Canaveral Air Force Station near Cocoa Beach, Florida and at [[Vandenberg AFB Space Launch Complex 4|SLC-4E]], at [[Vandenberg Air Force Base#Launch sites|Vandenberg Air Force Base launch sites]] 55 miles northwest of [[Santa Barbara, California|Santa Barbara]] California. Choice of launch site depended on mission parameters and mission goals.

===Variants and type identification===
The IV A (40nA) used boosters with steel casings, the IV B (40nB) used boosters with composite casings (the SRMU).

Type 401 used Centaur 3rd stage, type 402 used IUS 3rd stage. Other types (without 3rd stages) were 403, 404, and 405:

* Type 403 was no upper stage, for lower-mass payloads to higher orbits from Vandenburg.<ref name=At>http://www.astronautix.com/t/index.html</ref>
* Type 404 was no upper stage, for heavier payloads to low orbits, from Vandenburg.<ref name=At/>
* Type 405 was no upper stage, for lower-mass payloads to higher-orbit from Cape Canaveral.<ref name=At/>

== Background ==
[[File:Titan-IV.stl|alt=Interactive 3D model of the Titan IV|thumb|274x274px|Interactive 3D model of the Titan IV, fully assembled (left) and in exploded view (right).]]
The [[Titan (rocket family)|Titan rocket family]] was established in October 1955 when the Air Force awarded the [[Glenn L. Martin Company]] (later [[Martin-Marietta]], now part of [[Lockheed Martin]]) a contract to build an [[intercontinental ballistic missile]] ([[SM-68 Titan|SM-68]]). It became known as the [[Titan I]], the nation's first two-stage ICBM, and complemented the [[SM-65 Atlas|Atlas ICBM]] as the second underground, vertically stored, silo-based ICBM. Both stages of the Titan I used [[liquid oxygen]] and [[RP-1]] as propellants.

A subsequent version of the Titan family, the [[LGM-25C Titan II|Titan II]], was similar to the Titan I, but was much more powerful. Designated as LGM-25C, the Titan II was the largest missile developed for the USAF at that time. The Titan II had newly developed engines which used Aerozine 50 and nitrogen tetroxide as fuel and oxidizer in a self-igniting, [[hypergolic propellant]] combination, therefore allowing the Titan II to be stored underground ready to launch.

[[Titan III]] development began in 1964 with the Titan IIIA.

===Titan IV===
Years later{{when|date=November 2018}}, the Titan IVB evolved from the Titan III family and is similar to the Titan 34D. While the launcher family had an extremely good reliability record in its first two decades, this began to change in the 1980s with the loss of a Titan 34D in 1985 followed by the disastrous explosion of another in 1986 due to a [[solid rocket motor|SRM]] failure.

The Titan IV-B vehicle was intended to use the new composite-casing SRMs manufactured by Alliant Technologies rather than the old steel-casing SRMs produced by Chemical Systems Division (Titan IV-A would use the CSD motors). However, there were numerous development problems with them and so Lockheed-Martin put out a request to CSD to supply a few more of the old-style SRMs.

===1993 booster explosion===
On August 2, 1993, Titan IV K-11 lifted from SLC-4E carrying a NOSS SIGNIT satellite. Unusual for DOD launches, the Air Force invited the civilian press to cover the launch and it became more of a story than intended when the booster exploded 101 seconds after liftoff. Investigation found that another SRM burn-through had occurred, albeit much higher up and later in the flight than 34D-9. This incident was found to have been caused by an improper repair job on one of the SRMS.<ref>[http://www.astronautix.com/t/titan403a.html Titan 403A]</ref>

After Titan 34D-9, extensive measures had been put in place to ensure proper SRM operating condition which included X-raying the motor segments during prelaunch checks. The SRMs that went onto K-11 had originally been shipped to Cape Canaveral where X-rays revealed anomalies in the solid propellant mixture in one segment. Repair work was done on it, but further X-rays were still enough for CC personnel to disqualify them from flight. The SRMs were then shipped to Vandenberg and approved.

The repair work on the SRMs had involved workers making a pie-shaped cut in the propellant block to remove the defective area. However, most of CSD's qualified personnel had left the program by this point and so the repair crew in question did not know the proper procedure. After replacement, they neglected to seal the area where the cut in the propellant block had been made. The result was a near-repeat of 34D-9; a gap was left between the propellant and SRM casing so that another burn-through occurred during launch.

===Cassini–Huygens launch===
In 1997, a Titan IV-B rocket launched ''[[Cassini–Huygens]]'', a pair of probes sent to [[Saturn]]. It was the only use of a Titan IV for a non-Department of Defense launch. ''Huygens'' landed on [[Titan (moon)|Titan]] on January 14, 2005. ''Cassini'' remained in orbit around Saturn. The Cassini Mission ended on September 15, 2017 as it was manoeuvered into Saturn's atmosphere to burn up.

===1998 failure, and two in 1999===
1998 saw the worst accident when a launch of a Navy [[ELINT]] [[Mercury (satellite)]] from Cape Canaveral failed around 40 seconds into the flight. An electrical failure caused the Titan to suddenly pitch downward, the resulting aerodynamic stress causing one of the SRMs to separate. The ISDS (Inadvertent Separation Destruct System) automatically triggered, rupturing the SRM and taking the rest of the launch vehicle with it. At T+45 seconds, the Range Safety Officer sent the destruct command to ensure any remaining large pieces of the booster were broken up.<ref>[http://www.astronautix.com/lvs/titr401a.htm Titan Centaur 401A]</ref>

Investigation showed that Titan K-17, which was several years old and the last Titan IV-A to be launched, had dozens of damaged or chafed wires and should never have been launched in that operating condition, however the Air Force put extreme pressure on launch crews to meet program deadlines. The ultimate cause of the failure was an electrical short that caused a momentary power dropout to the guidance computer at T+39 seconds. After power was restored, the computer sent a spurious pitch down and yaw to the right command. At T+40 seconds, the Titan was travelling at near supersonic speed and could not handle this action without suffering a structural failure. In any case, the Titan's fuselage was filled with numerous sharp metal protrusions that made it nearly impossible to install, adjust, or remove wiring without it getting damaged. Quality control at Lockheed's Denver plant, where Titan vehicles were assembled, was described as "awful".

An extensive recovery effort was launched, both to diagnose the cause of the accident and recover debris from the classified satellite. All of the debris from the Titan had impacted offshore, between three and five miles downrange, and at least 30% of the booster was recovered from the sea floor. Debris continued to wash ashore for days afterward, and the salvage operation continued until October 15.

The Air Force had pushed for a "launch on demand" program for DOD payloads, something that was almost impossible to pull off especially given the lengthy preparation and processing time needed for a Titan IV launch (at least 60 days). General [[Chuck Horner]], shortly before retiring in 1994, had referred to the Titan program as "a nightmare". The 1998-99 schedule had called for four launches in less than 12 months. The first of these was Titan K-25 on May 9, 1998 which successfully orbited an Orion SIGNIT satellite. The second was K-17, and the third, delayed thanks to the investigation around K-17's failure, was K-32 on April 9, 1999 which carried a DSP early warning satellite. The IUS second stage failed to separate, leaving the payload in a useless orbit. Investigation into this failure found that wiring harnesses in the IUS had been wrapped too tightly with electrical tape so that a plug failed to disconnect properly and prevented the two IUS stages from separating.

The fourth launch was K-26 on April 30, which carried a Milstar communications satellite. During the Centaur's flight, an uncontrolled roll motion developed, causing the upper stage and payload rotate at ever-increasing rate. This threw the stage off course so when it came time for restart, the Centaur cartwheeled out of control and left its payload in a useless orbit. This failure was found to be the result of an incorrectly programmed equation in the guidance computer. The error caused the roll rate gyro data to be ignored by the flight computer, resulting in open-loop firing of the roll control thrusters until the RCS fuel was depleted.

===Solid Rocket Motor Upgrade test stand===
In 1988-89, The R. M. Parsons Company designed and built a full scale steel tower and deflector facility, which was used to test the Titan IV Solid Rocket Motor Upgrade (SRMU). The launch and the effect of the SRMU thrust force on the space shuttle vehicle were modeled. To evaluate the magnitude of the thrust force, the SRMU was connected to the steel tower through load measurement systems and launched in-place. It was the first full-scale test conducted to simulate the effects of the SRMU on the main space shuttle vehicle.<ref>Chalhoub, Michel S., (1990) "Dynamic Analysis, Design, and Execution of a Full Scale SRMU Test Stand," Parsons Engineering Report No. 027-90</ref>

===Aluminum-lithium tanks===
In the early 1980s, [[General Dynamics]] conceived of using a Space Shuttle to lift a [[Apollo Lunar Module|Lunar Module]] into orbit and then launch a Titan IV rocket with an [[Project Apollo|Apollo]]-type [[Service module|Service Module]] to rendezvous and dock—making a moonship for a lunar landing. The plan required the Space Shuttle and Titan IV to use [[aluminium-lithium alloy]] fuel tanks instead of aluminum to make a greater payload weight for takeoff. The original plan never came to fruition, but in the 1990s the Shuttle was converted to aluminum-lithium tanks to rendezvous with the highly inclined orbit of the Russian [[Mir]] [[Space station|Space Station]].

===Retirement===
The Titan family had become extremely expensive to fly by the 1990s and there were also growing safety concerns over its toxic propellants. The [[Atlas V]] rocket and the [[Delta IV rocket|Delta IV]] and [[Delta IV Heavy|its heavy rocket booster variant]] launch vehicles were designed to replace the Titan IVs. The next-generation ELVs such as Delta IV would use only solid motors and cryogenic propellants, as well they would be completely new, modern designs not derived from a 1960s missile system.

===Surviving examples===
In 2014, the [[National Museum of the United States Air Force]] in [[Dayton, Ohio]], began a project to restore a Titan IV-B rocket. This effort was successful, and on June 8, 2016 its display was opened.<ref>{{cite web|url=http://www.nationalmuseum.af.mil/Upcoming/PressRoom/News/ArticleDisplay/tabid/466/Article/792421/national-museum-of-the-us-air-force-fourth-building-now-open.aspx|title=National Museum of the U.S. Air Force fourth building now open|publisher=}}</ref> The only other surviving Titan IV core is on outdoor display at the [[Evergreen Aviation and Space Museum]], to include the stages and parts of the solid rocket motor assembly.<ref>http://www.spacearchive.info/news-2006-09-26-laafb.htm</ref>

==General characteristics==
* Primary Function: Space booster
* Builder: Lockheed-Martin Astronautics
* [[File:Bottom of First Stage of Titan IVB Rocket - LR87 rocket engine nozzles.jpg|alt=Bottom of two rocket nozzels and a partial view of the engines' pipes and machinery|thumb|Bottom of first stage of Titan IVB rocket]]Power Plant:
** Stage 0 consisted of two solid-rocket motors.
** Stage 1 used an LR87-AJ-11 liquid-propellant rocket engine.
** Stage 2 used the LR91-AJ-11 liquid-propellant engine.
** Optional upper stages included the [[Centaur (rocket stage)|Centaur]] and [[Inertial Upper Stage]].
* Guidance System: A [[Ring laser gyroscope|ring laser gyro]] guidance system manufactured by [[Honeywell]].
* Thrust:
** Stage 0: Solid rocket motors provide 1.7 million pounds force (7.56 MN) per motor at liftoff.
** Stage 1: LR87-AJ-11 provides an average of 548,000 pounds force (2.44 MN)
** Stage 2: LR91-AJ-11 provides an average of 105,000 pounds force (467 kN).
** Optional Centaur (RL10A-3-3A) upper stage provides 33,100 pounds force (147 kN) and the Inertial Upper Stage provides up to 41,500 pounds force (185 kN).
* Length: Up to {{convert|204|ft|m}}
* Lift Capability:
** Can carry up to {{convert|47800|lb|kg}} into a low Earth orbit
** up to {{convert|12700|lb|kg}} into a [[geosynchronous orbit]] when launched from Cape Canaveral AFS, Fla.;
** and up to {{convert|38800|lb|kg}} into a [[Low Earth orbit|low Earth]] [[polar orbit]] when launched from Vandenberg AFB.
** into geosynchronous orbit:
*** with Centaur upper stage {{convert|12700|lb|kg}}
*** with Inertial Upper Stage {{convert|5250|lb|kg}}
* [[Payload fairing]]:<ref>{{cite web |url=http://www.dtic.mil/dtic/tr/fulltext/u2/a259021.pdf |title=Analysis of Titan IV launch responsiveness |author=Michael Timothy Dunn |publisher=Air Force Institute of Technology|date=Dec 1992 |format=PDF |accessdate=2011-07-08}}</ref>
** Manufacturer: McDonnell Douglas Space Systems Co
** Diameter: {{convert|16.7|ft|m}}
** Length: 56, 66, 76, or 86 ft
** Mass: 11,000, 12,000, 13,000, or 14,000 lb
** Design: 3 sections, isogrid structure, Aluminum
* Maximum Takeoff Weight: Approximately 2.2 million pounds (1,000,000 kg)
* Cost: Approximately $250–350 million, depending on launch configuration.
* Date deployed: June 1989
* Launch sites: Cape Canaveral AFS, Fla., and Vandenberg AFB, Calif.

==Program cost==
In 1990, the Titan IV Selected Acquisition Report estimated the total cost for the acquisition of 65 Titan IV vehicles over a period of 16 years to US$18.3 billion (inflation-adjusted US$ {{formatnum:{{Inflation|US|18.3|1990|r=1}}}} billion in {{CURRENTISOYEAR}}).<ref name="GAO NSIA-91-271">{{cite web |url=http://archive.gao.gov/d19t9/144770.pdf|title=TITAN IV LAUNCH VEHICLE --- Restructured Program Could Reduce Fiscal Year 1992 Funding Needs|date=September 1991|publisher=US General Accounting Office|first=Nancy R.|last=Kingsbury}}</ref>

==Launch history==
{{Main article|List of Titan launches}}
{| class="wikitable collapsible"
|-
! Date / Time (UTC)
! Launch Site
! S/N
! Type
! Payload
! Outcome
! width=25% | Remarks
|-
| 14 June 1989 13:18
| [[Cape Canaveral Air Force Station|CCAFS]] [[Cape Canaveral Air Force Station Space Launch Complex 41|LC-41]]
| K-1
| 402A / [[Inertial Upper Stage|IUS]]
| USA-39 ([[Defense Support Program|DSP]]-14)
| {{Success}}
|
|-
| 8 June 1990 05:21
| CCAFS LC-41
| K-4
| 405A
| USA-60 ([[Naval Ocean Surveillance System|NOSS]]) USA-61 ([[Naval Ocean Surveillance System|NOSS]]) USA-62 ([[Naval Ocean Surveillance System|NOSS]]) USA-59 ([[Satellite Launch Dispenser Communications|SLDCOM]])
| {{Success}}
|
|-
| 13 November 1990 00:37
| CCAFS LC-41
| K-6
| 402A / [[Inertial Upper Stage|IUS]]
| USA-65 ([[Defense Support Program|DSP]]-15)
| {{Success}}
|
|-
| 8 March 1991 12:03
| [[Vandenberg AFB|VAFB]] [[Vandenberg AFB Space Launch Complex 4|LC-4E]]
| K-5
| 403A
| USA-69 ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
|
|-
| 8 November 1991 07:07
| VAFB LC-4E
| K-8
| 403A
| USA-74 ([[Naval Ocean Surveillance System|NOSS]]) USA-76 ([[Naval Ocean Surveillance System|NOSS]]) USA-77 ([[Naval Ocean Surveillance System|NOSS]]) USA-72 ([[Satellite Launch Dispenser Communications|SLDCOM]])
| {{Success}}
|
|-
| 28 November 1992 21:34
| VAFB LC-4E
| K-3
| 404A
| USA-86 ([[KH-11 Kennen|KH-11]])
| {{Success}}
|
|-
| 2 August 1993 19:59
| VAFB LC-4E
| K-11
| 403A
| [[Naval Ocean Surveillance System|NOSS]] x3 [[Satellite Launch Dispenser Communications|SLDCOM]]
| {{Failure}}
| SRM exploded at T+101s due to damage caused during maintenance on ground.
|-
| 7 February 1994 21:47
| CCAFS [[Cape Canaveral Air Force Station Space Launch Complex 40|LC-40]]
| K-10
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-99 ([[Milstar]]-1)
| {{Success}}
|
|-
| 3 May 1994 15:55
| CCAFS LC-41
| K-7
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-103 ([[Trumpet (satellite)|Trumpet]])
| {{Success}}
|
|-
| 27 August 1994 08:58
| CCAFS LC-41
| K-9
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-105 ([[Mercury (satellite)|Mercury]])
| {{Success}}
|
|-
| 22 December 1994 22:19
| CCAFS LC-40
| K-14
| 402A / [[Inertial Upper Stage|IUS]]
| USA-107 ([[Defense Support Program|DSP]]-17)
| {{Success}}
|
|-
| 14 May 1995 13:45
| CCAFS LC-40
| K-23
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-110 ([[Orion (satellite)|Orion]])
| {{Success}}
|
|-
| 10 July 1995 12:38
| CCAFS LC-41
| K-19
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-112 ([[Trumpet (satellite)|Trumpet]])
| {{Success}}
|
|-
| 6 November 1995 05:15
| CCAFS LC-40
| K-21
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-115 ([[Milstar]]-2)
| {{Success}}
|
|-
| 5 December 1995 21:18
| VAFB LC-4E
| K-15
| 404A
| USA-116 ([[KH-11 Kennen|KH-11]])
| {{Success}}
|
|-
| 24 April 1996 23:37
| CCAFS LC-41
| K-16
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-118 ([[Mercury (satellite)|Mercury]])
| {{Success}}
|
|-
| 12 May 1996 21:32
| VAFB LC-4E
| K-22
| 403A
| USA-120 ([[Naval Ocean Surveillance System|NOSS]]) USA-121 ([[Naval Ocean Surveillance System|NOSS]]) USA-122 ([[Naval Ocean Surveillance System|NOSS]]) USA-119 ([[Satellite Launch Dispenser Communications|SLDCOM]]) USA-123 ([[Tethers in Space Physics Satellite|TiPS]]) USA-124 ([[Tethers in Space Physics Satellite|TiPS]])
| {{Success}}
|
|-
| 3 July 1996 00:30
| CCAFS LC-40
| K-2
| 405A
| USA-125 ([[Satellite Data System|SDS]])
| {{Success}}
|
|-
| 20 December 1996 18:04
| VAFB LC-4E
| K-13
| 404A
| USA-129 ([[KH-11 Kennen|KH-11]])
| {{Success}}
| [[List of NRO Launches|NROL-2]]
|-
| 23 February 1997 20:20
| CCAFS LC-40
| B-24
| 402B / [[Inertial Upper Stage|IUS]]
| USA-130 ([[Defense Support Program|DSP]]-18)
| {{Success}}
|
|-
| 15 October 1997 08:43
| CCAFS LC-40
| B-33
| 401B / [[Centaur (rocket stage)|Centaur]]
| [[Cassini–Huygens|Cassini]] [[Huygens (spacecraft)|Huygens]]
| {{Success}}
|
|-
| 24 October 1997 02:32
| VAFB LC-4E
| A-18
| 403A
| USA-133 ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
| [[List of NRO Launches|NROL-3]]
|-
| 8 November 1997 02:05
| CCAFS LC-41
| A-17
| 401A / [[Centaur (rocket stage)|Centaur]]
| USA-136 ([[Trumpet (satellite)|Trumpet]])
| {{Success}}
| [[List of NRO Launches|NROL-4]]
|-
| 9 May 1998 01:38
| CCAFS LC-40
| B-25
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-139 ([[Orion (satellite)|Orion]])
| {{Success}}
| [[List of NRO Launches|NROL-6]]
|-
| 12 August 1998 11:30
| CCAFS LC-41
| A-20
| 401A / [[Centaur (rocket stage)|Centaur]]
| [[List of NRO Launches|NROL-7]] ([[Mercury (satellite)|Mercury]])
| {{Failure}}
| Guidance system short-circuited at T+40s due to frayed wire, vehicle lost control and destroyed by range safety.
|-
| 9 April 1999 17:01
| CCAFS LC-41
| B-27
| 402B / [[Inertial Upper Stage|IUS]]
| USA-142 ([[Defense Support Program|DSP]]-19)
| {{Failure}}
| Spacecraft failed to separate from IUS stage.
|-
| 30 April 1999 16:30
| CCAFS LC-40
| B-32
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-143 ([[Milstar]]-3)
| {{Failure}}
| Centaur software database error caused loss of [[attitude control]], insertion burns done incorrectly. Satellite deployed into useless orbit.
|-
| 22 May 1999 09:36
| VAFB LC-4E
| B-12
| 404B
| USA-144 ([[Misty (satellite)|Misty]])
| {{Success}}
| [[List of NRO Launches|NROL-8]]
|-
| 8 May 2000 16:01
| CCAFS LC-40
| B-29
| 402B / [[Inertial Upper Stage|IUS]]
| USA-149 ([[Defense Support Program|DSP]]-20)
| {{Success}}
|
|-
| 17 August 2000 23:45
| VAFB LC-4E
| B-28
| 403B
| USA-152 ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
| [[List of NRO Launches|NROL-11]]
|-
| 27 February 2001 21:20
| CCAFS LC-40
| B-41
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-157 ([[Milstar]]-4)
| {{Success}}
|
|-
| 6 August 2001 07:28
| CCAFS LC-40
| B-31
| 402B / [[Inertial Upper Stage|IUS]]
| USA-159 ([[Defense Support Program|DSP]]-21)
| {{Success}}
|
|-
| 5 October 2001 21:21
| VAFB LC-4E
| B-34
| 404B
| USA-161 ([[KH-11 Kennen|KH-11]])
| {{Success}}
| [[List of NRO Launches|NROL-14]]
|-
| 16 January 2002 00:30
| CCAFS LC-40
| B-38
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-164 ([[Milstar]]-5)
| {{Success}}
|
|-
| 8 April 2003 13:43
| CCAFS LC-40
| B-35
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-169 ([[Milstar]]-6)
| {{Success}}
|
|-
| 9 September 2003 04:29
| CCAFS LC-40
| B-36
| 401B / [[Centaur (rocket stage)|Centaur]]
| USA-171 ([[Orion (satellite)|Orion]])
| {{Success}}
| [[List of NRO Launches|NROL-19]]
|-
| 14 February 2004 18:50
| CCAFS LC-40
| B-39
| 402B / [[Inertial Upper Stage|IUS]]
| USA-176 ([[Defense Support Program|DSP]]-22)
| {{Success}}
|
|-
| 30 April 2005 00:50
| CCAFS LC-40
| B-30
| 405B
| USA-182 ([[Lacrosse (satellite)|Lacrosse]])
| {{Success}}
| [[List of NRO Launches|NROL-16]]
|-
| 19 October 2005 18:05
| VAFB LC-4E
| B-26
| 404B
| USA-186 ([[KH-11 Kennen|KH-11]])
| {{Success}}
| [[List of NRO Launches|NROL-20]]
|}

==See also==
* [[Comparison of heavy lift launch systems]]
* [[List of Titan launches]], Titan I, II, III & IV

== References ==
{{Reflist}}

==External links==
{{Commons category|Titan IV 4B-33}}
* [https://www.maxwell.af.mil/au/awc/space/factsheets/titan_ivb.htm USAF Titan IVB Fact Sheet]{{dead link|date=November 2017 |bot=InternetArchiveBot |fix-attempted=yes }}
* [https://web.archive.org/web/20080503143356/http://www.pr.afrl.af.mil/archive/video.html Titan IV Ignition Videos]
* [https://web.archive.org/web/20060929003140/http://saturn.jpl.nasa.gov/multimedia/videos/launch/index.cfm Cassini Huygens Aboard a Titan IV-B Launch Videos]
* [http://www.astronautix.com/craft/earccess.htm Early Lunar Access]

{{Titan rockets}}
{{USAF space vehicles}}
{{Expendable launch systems}}
{{US launch systems}}

[[Category:Lockheed Martin]]
[[Category:2005 in spaceflight]]
[[Category:Titan (rocket family)]]

H-IIB

2018-11-05T23:24:53Z

Blastr42:

{{Other uses|H2B (disambiguation)}}

{{Use dmy dates|date=September 2013}}
{{Infobox rocket
|name =H-IIB<ref>{{Cite web|url=http://global.jaxa.jp/projects/rockets/h2b/index.html|title=JAXA {{!}} H-IIB Launch Vehicle|website=JAXA {{!}} Japan Aerospace Exploration Agency|language=en-US|access-date=2016-04-07}}</ref>
|image = H-IIB F2 launching HTV2.jpg
|imsize = 250
|caption = Liftoff of H-IIB Flight 2
|function = [[Medium-lift launch vehicle]]
|manufacturer = [[Mitsubishi Heavy Industries]]
|country-origin =Japan
|cpl-year =
|cpl = {{US$|112.5 million[http://www.gao.gov/products/GAO-17-609]}}
|height = {{cvt|56.6|m}}
|diameter = {{cvt|5.2|m}}
|mass = {{cvt|531000|kg}}
|stages = 2
|family = [[H-II (rocket family)|H-II]]
|derivatives = [[H3_(rocket) |H3]]
| comparable = {{flatlist|
* [[Ariane 5#Variants|Ariane 5 ES]]
* [[Atlas V#Variants|Atlas V 541]]
* [[Falcon 9 Full Thrust]]
* [[Proton-M]]
}}
|capacities = 
{{Infobox rocket/payload
|location = [[Low Earth orbit|LEO]] 
|kilos = {{cvt|16,500|kg}}<ref name=GSP-H2B>{{cite web |url= http://space.skyrocket.de/doc_lau/h-2b.htm |title=H-2B |first=Gunter |last=Krebs |work=Gunter's Space Page |access-date=28 January 2017}}</ref> 
}}
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]] 
|kilos = {{cvt|8,000|kg}}<ref name=GSP-H2B /> 
}}

|status = Active
|sites = [[Tanegashima Space Center|Tanegashima]] [[Yoshinobu Launch Complex|LA-Y]]2
|first= 10 September 2009
|last= 22 September 2018
|launches = 7
|success = 7
|fail =
|partial =
|other =
|payloads = [[H-II Transfer Vehicle]]
|stagedata =
{{Infobox rocket/stage
|type = booster
|stageno =
|name = [[SRB-A|SRB-A3]]
|number = 4
|length = {{cvt|15|m}}
|diameter = {{cvt|2.5|m}}
|width = 
|empty = 
|gross = {{cvt|76,500|kg}} each 
|propmass = {{cvt|66,000|kg}} each 
|solid = yes 
|engines = off
|thrust = {{cvt|2,305|kN}}
|total = {{cvt|9,220|kN}}
|SI = {{convert|283.6|isp}}
|burntime = 114 seconds
|fuel = [[HTPB]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = First
|name =
|number =
|length = {{cvt|38|m}} 
|diameter = {{cvt|5.2|m}} 
|width = 
|empty = 
|gross = {{cvt|202,000|kg}}
|propmass = {{cvt|177,800|kg}}
|engines = 2 [[LE-7A]]
|thrust = {{cvt|2,196|kN}} (vacuum)
|total =
|SI = {{convert|440|isp}} (vacuum)
|burntime = 352 seconds
|fuel = [[LOX]] / [[LH2]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name =
|number =
|length = {{cvt|11|m}}
|diameter = {{cvt|4.0|m}}
|width = 
|empty = 
|gross = {{cvt|20,000|kg}}
|propmass = {{cvt|16600|kg}}
|engines = 1 [[LE-5B]]
|thrust = {{cvt|137|kN}} (vacuum)
|total =
|SI = {{convert|448|isp}} (vacuum)
|burntime = 499 seconds
|fuel = [[LOX]] / [[LH2]]
}}
}}

'''H-IIB''' ('''H2B''') is an [[expendable launch system]] used to launch [[H-II Transfer Vehicle]]s (HTV, or ''Kounotori'') towards the [[International Space Station]]. H-IIB [[rocket]]s are liquid-fuelled with solid-fuel [[Modular rocket|strap-on]] boosters and are launched from the [[Tanegashima Space Center]] in Japan. [[Mitsubishi Heavy Industries|Mitsubishi]] and [[JAXA]] have been primarily responsible for design, manufacture, and operation of H-IIB. H-IIB made its first flight in 2009, and had made a total of seven flights through 2018.

H-IIB is able to carry a payload of up to {{convert|8000|kg|lb}} to [[Geostationary transfer orbit|GTO]],<ref name=GSP-H2B /> compared with the payload of 4,000-6,000 kg for the [[H-IIA]], a predecessor design. Its performance to [[Low Earth orbit|LEO]] is sufficient for the {{convert|16,500|kg|adj=on}} [[H-II Transfer Vehicle|HTV]].<ref name=GSP-H2B /> The first H-IIB was launched in September 2009.<ref name=GSP-H2B />

==Development==
[[File:H-II series.png|left|270px|thumb|H-II series]]
The H-IIB launch vehicle is a launch vehicle developed jointly by [[JAXA]] and [[Mitsubishi Heavy Industries]] to launch the [[H-II Transfer Vehicle]]. The H-IIB was designed to adopt methods and components that have already been verified by flights on the [[H-IIA]], so that manufacturing the new launch vehicle would be more cost-effective, with less risk, in a shorter period of time. JAXA was in charge of preliminary design, readiness of the ground facility, and the development of new technologies for the H-IIB, in which the private sector has limited competencies, while the Mitsubishi Heavy Industries is responsible for manufacturing. JAXA successfully conducted eight firing tests of the new cluster design with the simulated first-stage propulsion system, called Battleship Firing Tests, since March 2008, at MHI's Tashiro Test Facility in [[Odate]], [[Akita Prefecture]].<ref>{{cite web|url=http://www.jaxa.jp/article/special/transportation/nakamura01_e.html|title=A new stage in Japanese space transportation|date=2007-07-15|publisher=JAXA|work=Tomihisa Nakamura|accessdate=2009-09-10}}</ref>

Before launch, two Captive Firing Tests were conducted on the H-IIB. The first test, which consisted of firing the first stage for ten seconds, was originally scheduled to occur at 02:30 GMT on 27 March 2009, however it was cancelled after the launch pad's coolant system failed to activate.<ref>{{cite web|url=http://www.jaxa.jp/press/2009/03/20090327_cft_e.html|title=Postponement of the First Captive Firing Test (CFT) of the First Stage Flight Model Tank for the H-IIB Launch Vehicle|publisher=JAXA|accessdate=2009-08-12|date=2009-03-27}}</ref> This was later discovered to have been due to a manual supply valve not being open.<ref>{{cite web|url=http://www.jaxa.jp/press/2009/03/20090330_cft_e.html|title=The First Captive Firing Test for the First Stage Flight Model Tank for the H-IIB Launch Vehicle|date=2009-03-30|publisher=JAXA|accessdate=2009-08-12}}</ref> The test was rescheduled for 1 April, but then postponed again due to a leak in a pipe associated with the launch facility's fire suppression system.<ref>{{cite web|url=http://www.jaxa.jp/press/2009/04/20090401_cft_e.html|title=Suspension of the First Captive Firing Test (CFT) of the First Stage Flight Model Tank for the H-IIB Launch Vehicle|date=2009-04-01|publisher=JAXA|accessdate=2009-08-12}}</ref> The test was rescheduled for 2 April,<ref>{{cite web|url=http://www.jaxa.jp/press/2009/04/20090401_cft2_e.html|title=The First Captive Firing Test for the First Stage Flight Model Tank for the H-IIB Launch Vehicle|publisher=JAXA|date=2009-04-01|accessdate=2009-08-12}}</ref> when it was successfully conducted at 05:00 GMT.<ref>{{cite web|url=http://www.jaxa.jp/press/2009/04/20090402_cft_e.html|title=Result of the First Captive Firing Test for the First Stage Flight Model Tank of the H-IIB Launch Vehicle|date=2009-04-02|publisher=JAXA|accessdate=2009-08-12}}</ref> Following this, the second test, which involved a 150-second burn of the first stage, was scheduled for 20 April.<ref>{{cite web|url=http://www.jaxa.jp/press/2009/04/20090417_cft_e.html|title=The Second Captive Firing Test for the First Stage Flight Model Tank for the H-IIB Launch Vehicle|date=2009-04-17|publisher=JAXA|accessdate=2009-08-12}}</ref> This was successfully conducted at 04:00 GMT on 22 April,<ref>{{cite web|url=http://www.jaxa.jp/press/2009/04/20090422_cft_e.html|title=Result of the Second Captive Firing Test for the First Stage Flight Model Tank of the H-IIB Launch Vehicle|date=2009-04-22|publisher=JAXA|accessdate=2009-08-12}}</ref> following a two-day delay due to unfavourable weather conditions.<ref>{{cite web|url=http://www.jaxa.jp/press/2009/04/20090419_cft_e.html|title=Postponement of the Second Captive Firing Test (CFT) of the First Stage Flight Model Tank for the H-IIB Launch Vehicle|date=2009-04-19|publisher=JAXA|accessdate=2009-08-12}}</ref> A ground test, using a [[battleship (rocketry)|battleship]] mockup of the rocket was subsequently conducted on 11 July.<ref>{{cite web|url=http://www.jaxa.jp/press/2009/07/20090711_gtv_e.html|title=Results of the H-IIB Launch Vehicle Ground Test Vehicle (GTV) Test|publisher=JAXA|date=2009-07-11|accessdate=2009-08-12}}</ref>

By 2009, the development program of the H-IIB had cost approximately 27 billion yen.<ref>[http://robot.watch.impress.co.jp/docs/news/20090710_301383.html JAXA、H-IIBロケットの地上総合試験(GTV)について説明], Robot Watch, 2009-7-10</ref>{{clarify|date=June 2015}}

==Vehicle description==
The H-IIB launch vehicle is a two-stage rocket. The first stage uses [[liquid oxygen]] and [[liquid hydrogen]] as propellants and has four strap-on [[solid rocket]] boosters ([[SRB-A|SRB-A3]]) powered by [[polybutadiene]]. The first stage is powered by two [[LE-7]]A engines, instead of one for the [[H-IIA]]. It has four SRB-As attached to the body, while the standard version of H-IIA has two SRB-As. In addition, the first-stage body of the H-IIB is 5.2m in diameter compared with 4m for the H-IIA. The total length of the first stage is extended by 1m from that of H-IIA. As a result, the H-IIB first stage holds 70% more propellant than that of the H-IIA. The second stage is powered by a single [[LE-5]]B engine.<ref>{{cite web|url=http://www.jaxa.jp/pr/brochure/pdf/01/rocket05.pdf|title=H-IIB|date=2009-07-15|publisher=Japanese Aerospace Exploration Agency|work=H-IIB Launch Vehicle|accessdate=2009-09-04|archiveurl = https://web.archive.org/web/20140326132047/http://www.jaxa.jp/pr/brochure/pdf/01/rocket05.pdf|archivedate = 2014-03-26}}</ref>

== Launch history ==
{{main|List of H-I and H-II launches}}

The first launch of the H-IIB occurred on 10 September 2009 at 1701 UTC. It successfully launched the [[HTV-1]], which was on a mission to resupply the [[International Space Station|International Space Station (ISS)]].<ref>{{cite web|url=http://news.bbc.co.uk/2/hi/science/nature/8249357.stm|title=Japan's space freighter in orbit |date=2009-08-10|publisher=BBC|work=Jonathan Amos|accessdate=2009-09-10}}</ref>

{| class="wikitable"
|-
! Flight #
! Variant
! Date of Launch ([[UTC]])
! Launch Location
! Payload
! Result
! Remarks
|-
| TF1
| H-IIB
| 10 September 2009 17:01:46
| [[Yoshinobu Launch Complex|LA-Y2]], [[Tanegashima Space Center|Tanegashima]]
| {{flagicon|Japan}} [[HTV-1]]
| {{bg-green}}|Success
| First flight of H-IIB
|-
| F2
| H-IIB
| 22 January 2011 05:37:57
| [[Yoshinobu Launch Complex|LA-Y2]], [[Tanegashima Space Center|Tanegashima]]
| {{flagicon|Japan}} [[Kounotori 2|HTV-2]]
| {{bg-green}}|Success
|
|-
| F3
| H-IIB
| 21 July 2012 02:06:18
| [[Yoshinobu Launch Complex|LA-Y2]], [[Tanegashima Space Center|Tanegashima]]
| {{flagicon|Japan}} [[Kounotori 3|HTV-3]] {{flagicon|JPN}} [[Raiko]]{{smallsup|*1}} {{flagicon|JPN}} [[We-Wish|We Wish]]{{smallsup|*1}} {{flagicon|JPN}} [[Niwaka]]{{smallsup|*1}} {{nowrap|{{flagicon|USA}} [[TechEdSat]]}}{{smallsup|*1}} {{flagicon|VIE}} [[F-1 (satellite)|F-1]]{{smallsup|*1}}
| {{bg-green}}|Success
| {{smallsup|*1}}[[CubeSat]]s carried aboard HTV, on 4 October 2012 deployed from the ISS
|-
| F4
| H-IIB
| 3 August 2013 19:48:46
| [[Yoshinobu Launch Complex|LA-Y2]], [[Tanegashima Space Center|Tanegashima]]
| {{flagicon|Japan}} [[Kounotori 4|HTV-4]] {{flagicon|JPN}} {{flagicon|VIE}} [[PicoDragon Satellite|Pico Dragon]]{{smallsup|*2}} {{flagicon|USA}} [[ArduSat-1]]{{smallsup|*2}} {{flagicon|USA}} [[ArduSat-X]]{{smallsup|*2}} {{nowrap|{{flagicon|USA}} [[TechEdSat-3p]]}}{{smallsup|*2}}
| {{bg-green}}|Success
| {{smallsup|*2}}[[CubeSat]]s carried aboard HTV for deployment from the ISS
|-
| F5
| H-IIB
| 19 August 2015 11:50:49
| [[Yoshinobu Launch Complex|LA-Y2]], [[Tanegashima Space Center|Tanegashima]]
| {{flagicon|Japan}} [[Kounotori 5|HTV-5]] {{flagicon|Brazil}} [[SERPENS]]{{smallsup|*3}} {{flagicon|Japan}} [[S-CUBE]]{{smallsup|*3}} {{flagicon|USA}} [[Flock-2b]] x 14{{smallsup|*3}} {{flagicon|Denmark}} [[GOMX-3]]{{smallsup|*3}} {{flagicon|Denmark}} [[AAUSAT5]]{{smallsup|*3}}
| {{bg-green}}|Success
| {{smallsup|*3}}[[CubeSat]]s carried aboard HTV for deployment from the ISS
|-
| F6
| H-IIB
| 9 December 2016 13:26:47
| [[Yoshinobu Launch Complex|LA-Y2]], [[Tanegashima Space Center|Tanegashima]]
| {{flagicon|Japan}} [[Kounotori 6|HTV-6]] {{flagicon|Japan}} AOBA-Velox III{{smallsup|*4}} {{flagicon|Italy}} {{flagicon|Brazil}} {{flagicon|USA}} TuPOD{{smallsup|*4}} {{flagicon|Japan}} EGG{{smallsup|*4}} {{flagicon|Japan}} ITF-2{{smallsup|*4}} {{flagicon|Japan}} STARS-C{{smallsup|*4}} {{flagicon|Japan}} FREEDOM{{smallsup|*4}} {{flagicon|Japan}} WASEDA-SAT3{{smallsup|*4}} {{flagicon|USA}} OSNSAT{{smallsup|*4}} {{flagicon|BRA}} [[Tancredo-1]]{{smallsup|*4}} {{flagicon|USA}} [[TechEdSat-5]]{{smallsup|*4}} {{flagicon|USA}} 4 × [[Lemur-2]]{{smallsup|*4}}
| {{bg-green}}|Success
| {{smallsup|*4}}[[CubeSat]]s carried aboard HTV for deployment from the ISS
|-
| F7
| H-IIB
| 22 September 2018 17:52:27
| [[Yoshinobu Launch Complex|LA-Y2]], [[Tanegashima Space Center|Tanegashima]]
| {{flagicon|Japan}} [[Kounotori 7|HTV-7]] {{flagicon|Japan}} [[SPATIUM-I]]{{smallsup|*5}} {{flagicon|Japan}} [[RSP-00]]{{smallsup|*5}} {{flagicon|Japan}} [[STARS-Me]]{{smallsup|*5}}
| {{bg-green}}|Success
| {{smallsup|*5}} [[CubeSat]]s carried aboard HTV for deployment from the ISS
|}

==See also==
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]

==References==
{{Reflist}}

== External links ==
* [http://www.jaxa.jp/projects/rockets/h2b/index_e.html JAXA | H-IIB Launch Vehicle]
* [https://web.archive.org/web/20090916013305/http://www.mhi.co.jp/en/technology/review/abstracte-45-4-16.html "Development Status of the H-IIB Launch Vehicle"]. Mitsubishi Heavy Industries Technical Review Volume 45 Number 4
*[http://www.asahi.com/special/rocket/h2b-3d/ H-2B rocket 3D model]

{{Mitsubishi Heavy Industries}}
{{Japanese launch systems}}
{{H-II Transfer Vehicles}}
{{Expendable launch systems}}

{{DEFAULTSORT:H-Iib}}
[[Category:Mitsubishi Heavy Industries space launch vehicles]]
[[Category:Vehicles introduced in 2009]]
[[Category:Expendable space launch systems]]

H-IIA

2018-11-05T23:17:12Z

Blastr42:

{{Other uses|H2A (disambiguation)}}

{{Infobox rocket
|name =H-IIA
|image =H IIA No. F23 with GPM on its way to the launchpad.jpg
|imsize = 300
|caption = H-IIA No. F23 rolls out to the launch pad in February 2014
|function = [[Medium-lift launch vehicle]]
|manufacturer = {{plainlist|
* [[Mitsubishi Heavy Industries]] (prime)
* [[Alliant Techsystems|ATK]] (sub)
}}
|country-origin = [[Japan]]
|cpl-year =
|cpl = {{US$|90 million[http://www.gao.gov/products/GAO-17-609]}}
|height = {{cvt|53|m}}
|diameter = {{cvt|4|m}}
|mass = {{cvt|285,000-445,000|kg}}
|stages = 2
|family = [[H-II (rocket family)|H-II]]
|derivatives = [[H-IIB]]
|capacities = 
{{Infobox rocket/payload
|location = [[Low Earth orbit|LEO]] 
|kilos = {{cvt|10,000-15,000|kg}} 
}}
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]] 
|kilos = {{cvt|4,100-6,000|kg}} 
}}

|status = Active
|sites = [[Tanegashima Space Center|Tanegashima]] [[Yoshinobu Launch Complex|LA-Y]]
|first = {{plainlist|
* '''202:''' 29 August 2001
* '''204:''' 18 December 2006
* '''2022:''' 26 February 2005
* '''2024:''' 4 February 2002
}}
|last = {{plainlist|
* '''202:''' 29 October 2018
* '''204:''' 19 August 2017
* '''2022:''' 14 September 2007
* '''2024:''' 23 February 2008
}}
|launches = {{flatlist|
* 40
** '''202:''' 26
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 7
}}
|success = {{flatlist|
* 39
** '''202:''' 26
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 6
}}
|fail =1 ('''2024''')
|partial =
|other =
|payloads = {{flatlist|
* [[SELENE]]
* [[Greenhouse Gases Observing Satellite|Ibuki]]
* [[Akatsuki (probe)|Akatsuki]]
}}


|stagedata =
{{Infobox rocket/stage
|type = booster 
|diff = All variants 
|stageno = 
|name = [[SRB-A]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|2,260|kN}} 
|total = {{cvt|4,520–9,040|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 120 seconds 
|fuel = [[HTPB]] 
}}
{{Infobox rocket/stage
|type = booster 
|diff = 2022 / 2024 
|stageno = 
|name = [[Castor (rocket stage)|Castor 4A-XL]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|745|kN}} 
|total = {{cvt|1,490–2,980|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 60 seconds 
|fuel = [[Solid rocket|Solid]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = First 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-7A]] 
|solid = 
|thrust = {{cvt|1,098|kN}} 
|total = 
|SI = {{convert|440|isp}} 
|burntime = 390 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = Second 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-5B]] 
|solid = 
|thrust = {{cvt|137|kN}} 
|total = 
|SI = {{convert|447|isp}} 
|burntime = 534 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
}}
[[Image:H-IIA F19 launching IGS-O4.jpg|right|250px|thumb|Liftoff of H-IIA Flight 19]]
[[Image:H-IIA Family.png|right|250px|thumb|H-IIA rocket lineup]]
[[Image:H-IIA-Launch-Vehicle.png|thumb|80px|H-IIA]]

'''H-IIA''' ('''H2A''') is an active [[expendable launch system]] operated by [[Mitsubishi Heavy Industries]] (MHI) for the [[JAXA|Japan Aerospace Exploration Agency]]. The liquid-fueled H-IIA [[rocket]]s have been used to launch [[satellite]]s into [[geostationary orbit]], to launch a lunar orbiting spacecraft, and to launch ''[[Akatsuki (spacecraft)|Akatsuki]]'', which studied the planet Venus. Launches occur at the [[Tanegashima Space Center]]. The H-IIA first flew in 2001. {{As of|December 2017}}, H-IIA rockets were launched 37 times, including 31 consecutive missions without a failure, dating back to November 29, 2003.

Production and management of the H-IIA shifted from JAXA to MHI on April 1, 2007. Flight 13, which launched the lunar orbiter [[SELENE]], was the first H-IIA launched after this privatization.<ref>{{cite web|url=http://www.satnews.com/stories2007/4356/ |title=Mitsubishi and Arianespace Combine Commercial Satellite Launch Services |publisher=SatNews |deadurl=yes |archiveurl=https://web.archive.org/web/20120208014829/http://www.satnews.com/stories2007/4356/ |archivedate=February 8, 2012 }}</ref>

The H-IIA is a derivative of the earlier [[H-II]] rocket, substantially redesigned to improve reliability and minimize costs. There are currently two (formerly four) different variants of the H-IIA in active service for various purposes. A derivative design, the [[H-IIB]], was developed in the 2000s and made its [[maiden flight]] in 2009.

== Vehicle description ==
The launch capability of an H-IIA launch vehicle can be enhanced by adding [[SRB-A]] ([[solid rocket booster]] or SRB) and [[Castor (rocket stage)|Castor 4AXL]] (solid strap-on booster or SSB) to its basic configuration, creating a "family". The models are indicated by three or four numbers following the prefix "H2A". The first number in the sequence indicates the number of stages; the second number of [[liquid rocket booster]]s (LRBs); the third number of SRBs; and, if present, the fourth number shows the number of SSBs.<ref name="leaflet">{{cite web |url=http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |title=H-IIA Launch Vehicle |accessdate=2007-09-15 |format=PDF |publisher=JAXA |pages=2 |deadurl=yes |archiveurl=https://web.archive.org/web/20080228013323/http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |archivedate=2008-02-28 |df= }}</ref> The first two figures are virtually fixed at "20", as H-IIA is always two-staged, and the plans for LRBs were cancelled and superseded by the [[H-IIB]].

== Variants ==

{| class="wikitable"
|-
! Designation!!Mass (tonnes)!!Payload (tonnes to [[Geostationary transfer orbit|GTO]])!!Addon modules
|-
| H2A 202||285||4.1||2 [[SRB-A]] (SRB)
|-
| H2A 2022 (discontinued)<ref>[https://web.archive.org/web/20070105140945/http://www.nikkei.co.jp/news/sangyo/20061205AT1D0300504122006.html 三菱重工、「H2A」2機種に半減・民営化でコスト減]. NIKKEI NET</ref>||316||4.5||2 SRB-A (SRB) + 2 [[Castor (rocket stage)|Castor 4AXL]] (SSB)
|-
| H2A 2024 (discontinued)||347||5||2 SRB-A (SRB) + 4 Castor 4AXL (SSB)
|-
| H2A 204||445||6||4 SRB-A (SRB)
|-
| H2A 212 (cancelled)||403||7.5||2 SRB-A (SRB) + 1 LRB
|-
| H2A 222 (cancelled)||520||9.5||2 SRB-A (SRB) + 2 LRBs
|}

== Launch history ==
{{main|List of H-I and H-II launches}}

The first H-IIA was successfully launched on August 29, 2001, followed by a string of successes.

The sixth launch on November 29, 2003, intended to launch two [[Information Gathering Satellite|IGS]] [[reconnaissance satellite]]s, failed. JAXA announced that launches would resume in 2005, and the first successful flight took place on February 26 with the launch of [[Multi-Functional Transport Satellite|MTSAT-1R]].

The first launch for a mission beyond Earth orbit was on September 14, 2007 for the [[SELENE]] moon mission. The first foreign payload on the H-IIA was the Australian FedSat-1 in 2002. As of March 2015, 27 out of 28 launches were successful.

A rocket with increased launch capabilities, [[H-IIB]], is a derivative of the H-IIA family. H-IIB uses two LE-7A engines in its first stage, as opposed to one in H-IIA. The first H-IIB was successfully launched on September 10, 2009.

For the 29th flight on November 24, 2015, an H-IIA with an upgraded second stage<ref>{{Cite web |url=http://global.jaxa.jp/press/2015/11/20151124_h2af29.html|title=Launch Result of Telstar 12 VANTAGE by H-IIA Launch Vehicle No. 29|publisher=JAXA|date=24 Nov 2015|accessdate=30 Nov 2015}}</ref> launched the Canadian Telstar 12V satellite, the first commercial primary payload for a Japanese launch vehicle.<ref>{{Cite web |url=http://www.nasaspaceflight.com/2015/11/japanese-h-iia-telstar-12v-launch/|title=Japanese H-IIA successfully lofts Telstar 12V|publisher=NASASpaceflight.com|author=William Graham|date=23 Nov 2015|accessdate=30 Nov 2015}}</ref>

{| class="wikitable"
!Date ([[UTC]]) !! Flight !! Type !! Payload(s) !! Outcome
|-
| August 29, 2001 07:00:00 || TF1 || H2A 202|| {{flagicon|Japan}} VEP 2 {{flagicon|Japan}} LRE || {{Success}}
|-
| February 4, 2002 02:45:00 || TF2 || H2A 2024 || {{flagicon|Japan}} VEP 3 {{flagicon|Japan}} [[MDS-1]] (Tsubasa) {{flagicon|Japan}} DASH || {{Success}}
|-
| September 10, 2002 08:20:00 || F3 || H2A 2024 || {{flagicon|Japan}} [[USERS]] {{flagicon|Japan}} [[DRTS]] (Kodama) || {{Success}}
|-
| December 14, 2002 01:31:00 || F4 || H2A 202 || {{flagicon|Japan}} [[ADEOS 2]] (Midori 2) {{flagicon|Japan}} WEOS (Kanta-kun) {{flagicon|Australia}} [[FedSat]] 1 {{flagicon|Japan}} Micro LabSat 1 || {{Success}}
|-
| March 28, 2003 01:27:00 || F5 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 1 {{flagicon|Japan}} IGS-Radar 1 || {{Success}}
|-
| rowspan=2 | {{nobr|November 29, 2003}} 04:33:00 || rowspan=2 | F6 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical (2) {{flagicon|Japan}} IGS-Radar (2) || {{Failure}}
|-
| colspan=3 style="background:linen;" | A hot gas leak from one SRB-A motor destroyed its separation system. The strap-on did not separate as planned, and the weight of the spent motor prevented the vehicle from achieving its planned height.<ref>{{cite web |url=http://www.jaxa.jp/press/2003/11/20031129_h2af6_e.html |title=Launch Result of IGS #2/H-IIA F6 |date=November 29, 2003 |accessdate=June 19, 2013 |publisher=JAXA}}</ref>
|-
| February 26, 2005 09:25:00 || F7 || H2A 2022 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-1R]] (Himawari 6) || {{Success}}
|-
| January 24, 2006 01:33:00 || F8 || H2A 2022 || {{flagicon|Japan}} [[ALOS]] (Daichi) || {{Success}}
|-
| February 18, 2006 06:27:00 || F9 || H2A 2024 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-2]] (Himawari 7) || {{Success}}
|-
| September 11, 2006 04:35:00 || F10 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 2 || {{Success}}
|-
| December 18, 2006 06:32:00 || F11 || H2A 204 || {{flagicon|Japan}} [[ETS-VIII]] (Kiku 8) || {{Success}}
|-
| February 24, 2007 04:41:00 || F12 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 2 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3V || {{Success}}
|-
| September 14, 2007 01:31:01 || F13 || H2A 2022 || {{flagicon|Japan}} [[SELENE]] (Kaguya) || {{Success}}
|-
| February 23, 2008 08:55:00 || F14 || H2A 2024 || {{flagicon|Japan}} [[WINDS]] (Kizuna) || {{Success}}
|-
| January 23, 2009 03:54:00 || F15 || H2A 202 || {{flagicon|Japan}} [[GOSAT]] (Ibuki) {{flagicon|Japan}} [[SDS-1]] {{flagicon|Japan}} STARS (Kūkai) {{flagicon|Japan}} KKS-1 (Kiseki) {{flagicon|Japan}} PRISM (Hitomi) {{flagicon|Japan}} [[Sohla]]-1 (Maido 1) {{flagicon|Japan}} SORUNSAT-1 (Kagayaki) {{flagicon|Japan}} SPRITE-SAT (Raijin) || {{Success}}<ref>{{cite web |url=http://www.jaxa.jp/press/2009/01/20090123_h2a-f15_e.html |title=Launch Result of the IBUKI (GOSAT) by H-IIA Launch Vehicle No. 15 |date=January 23, 2009 |publisher=MHI and JAXA}}</ref>
|-
| November 28, 2009 01:21:00 <ref>{{cite web|url=http://www.sorae.jp/030801/3328.html|title=H-IIA F16|publisher=Sorae|deadurl=yes|archiveurl=https://www.webcitation.org/64qmnLLfk?url=http://www.sorae.jp/030801/3328.html|archivedate=2012-01-21|df=}}</ref> || F16 || H2A 202|| {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3|| {{Success}}
|-
| May 20, 2010 21:58:22<ref>{{cite web |url=http://www.jaxa.jp/press/2010/03/20100303_h2af17_e.html |title=Launch Day of the H-IIA Launch Vehicle No. 17 |date=March 3, 2010 |publisher=JAXA}}</ref><ref>{{cite web |url=http://www.jaxa.jp/countdown/f17/overview/sub_payload_e.html |title=Overview of Secondary Payloads |publisher=JAXA}}</ref><ref>{{Cite web |url=http://www.space.com/missionlaunches/japan-venus-probe-launch-thursday-100518.html|title=New Venus Probe to Launch Thursday From Japan After|publisher=space.com|author=Tariq Malik|date=18 May 2010|accessdate=20 May 2010}}</ref> || F17 || H2A 202<ref name="nasa_f17">{{Cite web|url=http://www.nasaspaceflight.com/2010/05/axa-launch-h-iia-carrying-akatsuki-ikaros/|title=JAXA launch H-IIA carrying AKATSUKI and IKAROS scrubbed|author=Chris Bergin|date=17 May 2010|accessdate=17 May 2010|publisher=NASASpacflight.com}}</ref> || {{flagicon|Japan}} [[PLANET-C]] (Akatsuki) {{flagicon|Japan}} [[IKAROS]] {{flagicon|Japan}} [[UNITEC-1]] (Shin'en) {{flagicon|Japan}} [[Waseda-SAT2]] {{flagicon|Japan}} [[K-Sat]] (Hayato) {{flagicon|Japan}} [[Negai (satellite)|Negai☆″]]|| {{Success}}
|-
| September 11, 2010 11:17:00<ref>{{cite web |url=http://www.jaxa.jp/press/2010/08/20100804_michibiki_e.html |title=New Launch Day of the First Quasi-Zenith Satellite 'MICHIBIKI' by H-IIA Launch Vehicle No. 18 |publisher=JAXA}}</ref> || F18 || H2A 202 || {{flagicon|Japan}} [[Quasi-Zenith Satellite System|QZS-1]] (Michibiki) || {{Success}}
|-
| September 23, 2011 04:36:50<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/09/japanese-h-2a-launches-new-igs-military-satellite/|title=Japanese H-2A launches with new IGS military satellite |author=Chris Bergin|date=23 September 2011 |publisher= NASASpaceflight.com}}</ref> || F19 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 4 || {{Success}}
|-
| December 12, 2011 01:21:00<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/12/japanese-h-2a-lofts-igs-radar-3-satellite-into-orbit/ |author=Chris Bergin|date=11 December 2011 |publisher= NASASpaceflight.com|title=Japanese H-2A lofts IGS (Radar-3) satellite into orbit}}</ref> || F20 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 3 || {{Success}}
|-
| May 17, 2012 16:39:00 || F21 || H2A 202<ref>{{cite web |url=http://h2a.mhi.co.jp/en/f21/overview/index.html |title=Launch Overview – H-IIA Launch Services Flight No.21 |accessdate=April 15, 2012 |publisher=Mitsubishi Heavy Industries}}</ref> || {{flagicon|Japan}} [[GCOM-W]]1 (Shizuku) {{flagicon|South Korea}} [[KOMPSAT-3]] (Arirang 3) {{flagicon|Japan}} [[SDS-4]] {{flagicon|Japan}} [[HORYU-2]] || {{Success}}
|-
| January 27, 2013 04:40:00 || F22 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 4 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5V|| {{Success}}
|-
| February 27, 2014 18:37:00 || F23 || H2A 202 || {{flagicon|Japan}} {{flagicon|USA}} [[Global Precipitation Measurement|GPM-Core]] {{flagicon|JPN}} SindaiSat (Ginrei) {{flagicon|JPN}} STARS-II (Gennai) {{flagicon|JPN}} TeikyoSat-3 {{flagicon|JPN}} ITF-1 (Yui) {{flagicon|JPN}} OPUSAT (CosMoz) {{flagicon|JPN}} INVADER {{flagicon|JPN}} KSAT2|| {{Success}}
|-
| May 24, 2014 03:05:14 || F24 || H2A 202 || {{flagicon|Japan}} [[ALOS-2]] (Daichi 2) {{flagicon|JPN}} [[RISING-2]] {{flagicon|JPN}} [[UNIFORM-1]] {{flagicon|JPN}} [[SOCRATES (satellite)|SOCRATES]] {{flagicon|JPN}} SPROUT|| {{Success}}
|-
| October 7, 2014 05:16:00 || F25 || H2A 202 || {{flagicon|Japan}} [[Himawari 8]] || {{Success}}
|-
| December 3, 2014 04:22:04 || F26 || H2A 202 || {{flagicon|Japan}} [[Hayabusa 2]] {{flagicon|Japan}} [[Shin'en 2]] {{flagicon|Japan}} ARTSAT2-DESPATCH {{flagicon|Japan}} [[PROCYON]]|| {{Success}}
|-
| February 1, 2015 01:21:00 || F27 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar Spare|| {{Success}}
|-
| March 26, 2015 01:21:00 || F28 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5|| {{Success}}
|-
| November 24, 2015 06:50:00 || F29 || H2A 204 || {{flagicon|Canada}} [[Telstar 12V|Telstar 12 Vantage]] ||{{Success}}
|-
| rowspan=2 | February 17, 2016 08:45:00 || rowspan=2 | F30 || H2A 202 || {{flagicon|Japan}} [[ASTRO-H]] (Hitomi) {{flagicon|Japan}} ChubuSat-2 (Kinshachi 2) {{flagicon|Japan}} ChubuSat-3 (Kinshachi 3) {{flagicon|Japan}} Horyu-4 ||{{Success}}
|-
| colspan=3 style="background:linen;" | The Hitomi telescope broke apart 37 days after launch.<ref name="clark-20160418">{{cite news |url=http://spaceflightnow.com/2016/04/18/spinning-japanese-astronomy-satellite-may-be-beyond-saving/ |title=Attitude control failures led to break-up of Japanese astronomy satellite |work=Spaceflight Now |first=Stephen |last=Clark |date=18 April 2016 |accessdate=21 April 2016}}</ref>
|-
| November 2, 2016 06:20:00 || F31 || H2A 202 || {{flagicon|Japan}} [[Himawari 9]] ||{{Success}}
|-
| January 24, 2017 07:44:00 || F32 || H2A 204 || {{flagicon|Japan}} [[DSN-2]] (Kirameki 2) || {{Success}}
|-
| March 17, 2017 01:20:00 || F33 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 5 || {{Success}}
|-
| June 1, 2017 00:17:46 || F34 || H2A 202 || {{flagicon|Japan}} [[QZS-2]] (Michibiki 2) || {{Success}}
|-
| August 19, 2017 05:29:00 || F35 || H2A 204 || {{flagicon|Japan}} [[QZS-3]] (Michibiki 3) || {{Success}}
|-
| October 9, 2017 22:01:37 || F36 || H2A 202 || {{flagicon|Japan}} [[QZS-4]] (Michibiki 4) || {{Success}}
|-
| December 23, 2017 01:26:22 || F37 || H2A 202 || {{flagicon|Japan}} [[GCOM-C]] (Shikisai) {{flagicon|Japan}} [[SLATS]] (Tsubame) || {{Success}}
|-
| February 27, 2018 04:34:00 || F38 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 6 || {{Success}}
|-
| June 12, 2018 04:20:00 || F39 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 6 || {{Success}}
|-
| October 29, 2018 04:08:00 || F40 || H2A 202 || {{flagicon|Japan}} [[GOSAT-2]] (Ibuki-2) || {{Success}}
|-
|}

==See also==
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]

== References ==
'''Notes'''
{{Reflist|30em}}

'''Sources'''
{{Refbegin}}
* {{Cite web|title=Japan Prepares for Crucial Rocket Launch|work=SPACE.com|url=http://www.space.com/missionlaunches/ap_jaxa_h2a_050209.html|accessdate=16 February 2005 }}
* {{Cite web|title=H-IIA Expendable Launch Vehicle|work=SPACEandTECH|url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|accessdate=February 16, 2005|deadurl=yes|archiveurl=https://www.webcitation.org/64qmrxW1D?url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|archivedate=January 21, 2012|df=}}
{{Refend}}

==External links==
{{commons category|H-IIA}}
* [http://h2a.mhi.co.jp/en/ H-IIA LAUNCH SERVICES], Mitsubishi Heavy Industries
* [http://www.jaxa.jp/projects/rockets/h2a/index_e.html JAXA H-IIA English page]
* [https://web.archive.org/web/20070321160909/http://www.jaxa.jp/index_e.html JAXA English page]
* [http://www.jaxa.jp/projects/in_progress_e.html JAXA Launch Schedule]
* [http://www.jaxa.jp/about/centers/tnsc/index_e.html Tanegashima Space Center]
* [https://web.archive.org/web/20050404015815/http://visit.jaxa.jp/tanegashima/index_e.html "Tanegashima Space Center"– VISIT JAXA --]
* [https://web.archive.org/web/20041015211458/http://www.astronautix.com/lvs/h2a.htm Encyclopedia Astronautica page]
* [http://spaceflightnow.com/h2a/f6/ Failed Launch, 11-29-2003]
* [http://www.spaceflightnow.com/h2a/f2/020201rocket.html Image]
* [http://www.spaceflightnow.com/h2a/f3/020908rocket.html Launch 2 Image]

{{Mitsubishi Heavy Industries}}
{{Expendable launch systems}}
{{Japanese launch systems}}

{{DEFAULTSORT:H-Iia}}
[[Category:Expendable space launch systems]]
[[Category:Mitsubishi Heavy Industries space launch vehicles]]
[[Category:Vehicles introduced in 2001]]

[[de:H-II#H-IIA]]

H-IIA

2018-11-05T23:16:29Z

Blastr42:

{{Other uses|H2A (disambiguation)}}

{{Infobox rocket
|name =H-IIA
|image =H IIA No. F23 with GPM on its way to the launchpad.jpg
|imsize = 300
|caption = H-IIA No. F23 rolls out to the launch pad in February 2014
|function = [[Medium-lift launch vehicle]]
|manufacturer = {{plainlist|
* [[Mitsubishi Heavy Industries]] (prime)
* [[Alliant Techsystems|ATK]] (sub)
}}
|country-origin = [[Japan]]
|cpl-year =
|cpl = {{US$|90 million[http://www.gao.gov/products/GAO-17-609]}}
|height = {{cvt|53|m}}
|diameter = {{cvt|4|m}}
|mass = {{cvt|285,000-445,000|kg}}
|stages = 2
|family = [[H-II (rocket family)|H-II]]
|derivatives = [[H-IIB]]
|capacities = 
{{Infobox rocket/payload
|location = [[Low Earth orbit|LEO]] 
|kilos = {{cvt|10,000-15,000|kg}} 
}}
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]] 
|kilos = {{cvt|4,100-6,000|kg}} 
}}

|status = Active
|sites = [[Tanegashima Space Center|Tanegashima]] [[Yoshinobu Launch Complex|LA-Y]]
|first = {{plainlist|
* '''202:''' 29 August 2001
* '''204:''' 18 December 2006
* '''2022:''' 26 February 2005
* '''2024:''' 4 February 2002
}}
|last = {{plainlist|
* '''202:''' 29 October 2018
* '''204:''' 19 August 2017
* '''2022:''' 14 September 2007
* '''2024:''' 23 February 2008
}}
|launches = {{flatlist|
* 40
** '''202:''' 26
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 7
}}
|success = {{flatlist|
* 38
** '''202:''' 26
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 6
}}
|fail =1 ('''2024''')
|partial =
|other =
|payloads = {{flatlist|
* [[SELENE]]
* [[Greenhouse Gases Observing Satellite|Ibuki]]
* [[Akatsuki (probe)|Akatsuki]]
}}


|stagedata =
{{Infobox rocket/stage
|type = booster 
|diff = All variants 
|stageno = 
|name = [[SRB-A]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|2,260|kN}} 
|total = {{cvt|4,520–9,040|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 120 seconds 
|fuel = [[HTPB]] 
}}
{{Infobox rocket/stage
|type = booster 
|diff = 2022 / 2024 
|stageno = 
|name = [[Castor (rocket stage)|Castor 4A-XL]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|745|kN}} 
|total = {{cvt|1,490–2,980|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 60 seconds 
|fuel = [[Solid rocket|Solid]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = First 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-7A]] 
|solid = 
|thrust = {{cvt|1,098|kN}} 
|total = 
|SI = {{convert|440|isp}} 
|burntime = 390 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = Second 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-5B]] 
|solid = 
|thrust = {{cvt|137|kN}} 
|total = 
|SI = {{convert|447|isp}} 
|burntime = 534 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
}}
[[Image:H-IIA F19 launching IGS-O4.jpg|right|250px|thumb|Liftoff of H-IIA Flight 19]]
[[Image:H-IIA Family.png|right|250px|thumb|H-IIA rocket lineup]]
[[Image:H-IIA-Launch-Vehicle.png|thumb|80px|H-IIA]]

'''H-IIA''' ('''H2A''') is an active [[expendable launch system]] operated by [[Mitsubishi Heavy Industries]] (MHI) for the [[JAXA|Japan Aerospace Exploration Agency]]. The liquid-fueled H-IIA [[rocket]]s have been used to launch [[satellite]]s into [[geostationary orbit]], to launch a lunar orbiting spacecraft, and to launch ''[[Akatsuki (spacecraft)|Akatsuki]]'', which studied the planet Venus. Launches occur at the [[Tanegashima Space Center]]. The H-IIA first flew in 2001. {{As of|December 2017}}, H-IIA rockets were launched 37 times, including 31 consecutive missions without a failure, dating back to November 29, 2003.

Production and management of the H-IIA shifted from JAXA to MHI on April 1, 2007. Flight 13, which launched the lunar orbiter [[SELENE]], was the first H-IIA launched after this privatization.<ref>{{cite web|url=http://www.satnews.com/stories2007/4356/ |title=Mitsubishi and Arianespace Combine Commercial Satellite Launch Services |publisher=SatNews |deadurl=yes |archiveurl=https://web.archive.org/web/20120208014829/http://www.satnews.com/stories2007/4356/ |archivedate=February 8, 2012 }}</ref>

The H-IIA is a derivative of the earlier [[H-II]] rocket, substantially redesigned to improve reliability and minimize costs. There are currently two (formerly four) different variants of the H-IIA in active service for various purposes. A derivative design, the [[H-IIB]], was developed in the 2000s and made its [[maiden flight]] in 2009.

== Vehicle description ==
The launch capability of an H-IIA launch vehicle can be enhanced by adding [[SRB-A]] ([[solid rocket booster]] or SRB) and [[Castor (rocket stage)|Castor 4AXL]] (solid strap-on booster or SSB) to its basic configuration, creating a "family". The models are indicated by three or four numbers following the prefix "H2A". The first number in the sequence indicates the number of stages; the second number of [[liquid rocket booster]]s (LRBs); the third number of SRBs; and, if present, the fourth number shows the number of SSBs.<ref name="leaflet">{{cite web |url=http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |title=H-IIA Launch Vehicle |accessdate=2007-09-15 |format=PDF |publisher=JAXA |pages=2 |deadurl=yes |archiveurl=https://web.archive.org/web/20080228013323/http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |archivedate=2008-02-28 |df= }}</ref> The first two figures are virtually fixed at "20", as H-IIA is always two-staged, and the plans for LRBs were cancelled and superseded by the [[H-IIB]].

== Variants ==

{| class="wikitable"
|-
! Designation!!Mass (tonnes)!!Payload (tonnes to [[Geostationary transfer orbit|GTO]])!!Addon modules
|-
| H2A 202||285||4.1||2 [[SRB-A]] (SRB)
|-
| H2A 2022 (discontinued)<ref>[https://web.archive.org/web/20070105140945/http://www.nikkei.co.jp/news/sangyo/20061205AT1D0300504122006.html 三菱重工、「H2A」2機種に半減・民営化でコスト減]. NIKKEI NET</ref>||316||4.5||2 SRB-A (SRB) + 2 [[Castor (rocket stage)|Castor 4AXL]] (SSB)
|-
| H2A 2024 (discontinued)||347||5||2 SRB-A (SRB) + 4 Castor 4AXL (SSB)
|-
| H2A 204||445||6||4 SRB-A (SRB)
|-
| H2A 212 (cancelled)||403||7.5||2 SRB-A (SRB) + 1 LRB
|-
| H2A 222 (cancelled)||520||9.5||2 SRB-A (SRB) + 2 LRBs
|}

== Launch history ==
{{main|List of H-I and H-II launches}}

The first H-IIA was successfully launched on August 29, 2001, followed by a string of successes.

The sixth launch on November 29, 2003, intended to launch two [[Information Gathering Satellite|IGS]] [[reconnaissance satellite]]s, failed. JAXA announced that launches would resume in 2005, and the first successful flight took place on February 26 with the launch of [[Multi-Functional Transport Satellite|MTSAT-1R]].

The first launch for a mission beyond Earth orbit was on September 14, 2007 for the [[SELENE]] moon mission. The first foreign payload on the H-IIA was the Australian FedSat-1 in 2002. As of March 2015, 27 out of 28 launches were successful.

A rocket with increased launch capabilities, [[H-IIB]], is a derivative of the H-IIA family. H-IIB uses two LE-7A engines in its first stage, as opposed to one in H-IIA. The first H-IIB was successfully launched on September 10, 2009.

For the 29th flight on November 24, 2015, an H-IIA with an upgraded second stage<ref>{{Cite web |url=http://global.jaxa.jp/press/2015/11/20151124_h2af29.html|title=Launch Result of Telstar 12 VANTAGE by H-IIA Launch Vehicle No. 29|publisher=JAXA|date=24 Nov 2015|accessdate=30 Nov 2015}}</ref> launched the Canadian Telstar 12V satellite, the first commercial primary payload for a Japanese launch vehicle.<ref>{{Cite web |url=http://www.nasaspaceflight.com/2015/11/japanese-h-iia-telstar-12v-launch/|title=Japanese H-IIA successfully lofts Telstar 12V|publisher=NASASpaceflight.com|author=William Graham|date=23 Nov 2015|accessdate=30 Nov 2015}}</ref>

{| class="wikitable"
!Date ([[UTC]]) !! Flight !! Type !! Payload(s) !! Outcome
|-
| August 29, 2001 07:00:00 || TF1 || H2A 202|| {{flagicon|Japan}} VEP 2 {{flagicon|Japan}} LRE || {{Success}}
|-
| February 4, 2002 02:45:00 || TF2 || H2A 2024 || {{flagicon|Japan}} VEP 3 {{flagicon|Japan}} [[MDS-1]] (Tsubasa) {{flagicon|Japan}} DASH || {{Success}}
|-
| September 10, 2002 08:20:00 || F3 || H2A 2024 || {{flagicon|Japan}} [[USERS]] {{flagicon|Japan}} [[DRTS]] (Kodama) || {{Success}}
|-
| December 14, 2002 01:31:00 || F4 || H2A 202 || {{flagicon|Japan}} [[ADEOS 2]] (Midori 2) {{flagicon|Japan}} WEOS (Kanta-kun) {{flagicon|Australia}} [[FedSat]] 1 {{flagicon|Japan}} Micro LabSat 1 || {{Success}}
|-
| March 28, 2003 01:27:00 || F5 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 1 {{flagicon|Japan}} IGS-Radar 1 || {{Success}}
|-
| rowspan=2 | {{nobr|November 29, 2003}} 04:33:00 || rowspan=2 | F6 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical (2) {{flagicon|Japan}} IGS-Radar (2) || {{Failure}}
|-
| colspan=3 style="background:linen;" | A hot gas leak from one SRB-A motor destroyed its separation system. The strap-on did not separate as planned, and the weight of the spent motor prevented the vehicle from achieving its planned height.<ref>{{cite web |url=http://www.jaxa.jp/press/2003/11/20031129_h2af6_e.html |title=Launch Result of IGS #2/H-IIA F6 |date=November 29, 2003 |accessdate=June 19, 2013 |publisher=JAXA}}</ref>
|-
| February 26, 2005 09:25:00 || F7 || H2A 2022 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-1R]] (Himawari 6) || {{Success}}
|-
| January 24, 2006 01:33:00 || F8 || H2A 2022 || {{flagicon|Japan}} [[ALOS]] (Daichi) || {{Success}}
|-
| February 18, 2006 06:27:00 || F9 || H2A 2024 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-2]] (Himawari 7) || {{Success}}
|-
| September 11, 2006 04:35:00 || F10 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 2 || {{Success}}
|-
| December 18, 2006 06:32:00 || F11 || H2A 204 || {{flagicon|Japan}} [[ETS-VIII]] (Kiku 8) || {{Success}}
|-
| February 24, 2007 04:41:00 || F12 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 2 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3V || {{Success}}
|-
| September 14, 2007 01:31:01 || F13 || H2A 2022 || {{flagicon|Japan}} [[SELENE]] (Kaguya) || {{Success}}
|-
| February 23, 2008 08:55:00 || F14 || H2A 2024 || {{flagicon|Japan}} [[WINDS]] (Kizuna) || {{Success}}
|-
| January 23, 2009 03:54:00 || F15 || H2A 202 || {{flagicon|Japan}} [[GOSAT]] (Ibuki) {{flagicon|Japan}} [[SDS-1]] {{flagicon|Japan}} STARS (Kūkai) {{flagicon|Japan}} KKS-1 (Kiseki) {{flagicon|Japan}} PRISM (Hitomi) {{flagicon|Japan}} [[Sohla]]-1 (Maido 1) {{flagicon|Japan}} SORUNSAT-1 (Kagayaki) {{flagicon|Japan}} SPRITE-SAT (Raijin) || {{Success}}<ref>{{cite web |url=http://www.jaxa.jp/press/2009/01/20090123_h2a-f15_e.html |title=Launch Result of the IBUKI (GOSAT) by H-IIA Launch Vehicle No. 15 |date=January 23, 2009 |publisher=MHI and JAXA}}</ref>
|-
| November 28, 2009 01:21:00 <ref>{{cite web|url=http://www.sorae.jp/030801/3328.html|title=H-IIA F16|publisher=Sorae|deadurl=yes|archiveurl=https://www.webcitation.org/64qmnLLfk?url=http://www.sorae.jp/030801/3328.html|archivedate=2012-01-21|df=}}</ref> || F16 || H2A 202|| {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3|| {{Success}}
|-
| May 20, 2010 21:58:22<ref>{{cite web |url=http://www.jaxa.jp/press/2010/03/20100303_h2af17_e.html |title=Launch Day of the H-IIA Launch Vehicle No. 17 |date=March 3, 2010 |publisher=JAXA}}</ref><ref>{{cite web |url=http://www.jaxa.jp/countdown/f17/overview/sub_payload_e.html |title=Overview of Secondary Payloads |publisher=JAXA}}</ref><ref>{{Cite web |url=http://www.space.com/missionlaunches/japan-venus-probe-launch-thursday-100518.html|title=New Venus Probe to Launch Thursday From Japan After|publisher=space.com|author=Tariq Malik|date=18 May 2010|accessdate=20 May 2010}}</ref> || F17 || H2A 202<ref name="nasa_f17">{{Cite web|url=http://www.nasaspaceflight.com/2010/05/axa-launch-h-iia-carrying-akatsuki-ikaros/|title=JAXA launch H-IIA carrying AKATSUKI and IKAROS scrubbed|author=Chris Bergin|date=17 May 2010|accessdate=17 May 2010|publisher=NASASpacflight.com}}</ref> || {{flagicon|Japan}} [[PLANET-C]] (Akatsuki) {{flagicon|Japan}} [[IKAROS]] {{flagicon|Japan}} [[UNITEC-1]] (Shin'en) {{flagicon|Japan}} [[Waseda-SAT2]] {{flagicon|Japan}} [[K-Sat]] (Hayato) {{flagicon|Japan}} [[Negai (satellite)|Negai☆″]]|| {{Success}}
|-
| September 11, 2010 11:17:00<ref>{{cite web |url=http://www.jaxa.jp/press/2010/08/20100804_michibiki_e.html |title=New Launch Day of the First Quasi-Zenith Satellite 'MICHIBIKI' by H-IIA Launch Vehicle No. 18 |publisher=JAXA}}</ref> || F18 || H2A 202 || {{flagicon|Japan}} [[Quasi-Zenith Satellite System|QZS-1]] (Michibiki) || {{Success}}
|-
| September 23, 2011 04:36:50<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/09/japanese-h-2a-launches-new-igs-military-satellite/|title=Japanese H-2A launches with new IGS military satellite |author=Chris Bergin|date=23 September 2011 |publisher= NASASpaceflight.com}}</ref> || F19 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 4 || {{Success}}
|-
| December 12, 2011 01:21:00<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/12/japanese-h-2a-lofts-igs-radar-3-satellite-into-orbit/ |author=Chris Bergin|date=11 December 2011 |publisher= NASASpaceflight.com|title=Japanese H-2A lofts IGS (Radar-3) satellite into orbit}}</ref> || F20 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 3 || {{Success}}
|-
| May 17, 2012 16:39:00 || F21 || H2A 202<ref>{{cite web |url=http://h2a.mhi.co.jp/en/f21/overview/index.html |title=Launch Overview – H-IIA Launch Services Flight No.21 |accessdate=April 15, 2012 |publisher=Mitsubishi Heavy Industries}}</ref> || {{flagicon|Japan}} [[GCOM-W]]1 (Shizuku) {{flagicon|South Korea}} [[KOMPSAT-3]] (Arirang 3) {{flagicon|Japan}} [[SDS-4]] {{flagicon|Japan}} [[HORYU-2]] || {{Success}}
|-
| January 27, 2013 04:40:00 || F22 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 4 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5V|| {{Success}}
|-
| February 27, 2014 18:37:00 || F23 || H2A 202 || {{flagicon|Japan}} {{flagicon|USA}} [[Global Precipitation Measurement|GPM-Core]] {{flagicon|JPN}} SindaiSat (Ginrei) {{flagicon|JPN}} STARS-II (Gennai) {{flagicon|JPN}} TeikyoSat-3 {{flagicon|JPN}} ITF-1 (Yui) {{flagicon|JPN}} OPUSAT (CosMoz) {{flagicon|JPN}} INVADER {{flagicon|JPN}} KSAT2|| {{Success}}
|-
| May 24, 2014 03:05:14 || F24 || H2A 202 || {{flagicon|Japan}} [[ALOS-2]] (Daichi 2) {{flagicon|JPN}} [[RISING-2]] {{flagicon|JPN}} [[UNIFORM-1]] {{flagicon|JPN}} [[SOCRATES (satellite)|SOCRATES]] {{flagicon|JPN}} SPROUT|| {{Success}}
|-
| October 7, 2014 05:16:00 || F25 || H2A 202 || {{flagicon|Japan}} [[Himawari 8]] || {{Success}}
|-
| December 3, 2014 04:22:04 || F26 || H2A 202 || {{flagicon|Japan}} [[Hayabusa 2]] {{flagicon|Japan}} [[Shin'en 2]] {{flagicon|Japan}} ARTSAT2-DESPATCH {{flagicon|Japan}} [[PROCYON]]|| {{Success}}
|-
| February 1, 2015 01:21:00 || F27 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar Spare|| {{Success}}
|-
| March 26, 2015 01:21:00 || F28 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5|| {{Success}}
|-
| November 24, 2015 06:50:00 || F29 || H2A 204 || {{flagicon|Canada}} [[Telstar 12V|Telstar 12 Vantage]] ||{{Success}}
|-
| rowspan=2 | February 17, 2016 08:45:00 || rowspan=2 | F30 || H2A 202 || {{flagicon|Japan}} [[ASTRO-H]] (Hitomi) {{flagicon|Japan}} ChubuSat-2 (Kinshachi 2) {{flagicon|Japan}} ChubuSat-3 (Kinshachi 3) {{flagicon|Japan}} Horyu-4 ||{{Success}}
|-
| colspan=3 style="background:linen;" | The Hitomi telescope broke apart 37 days after launch.<ref name="clark-20160418">{{cite news |url=http://spaceflightnow.com/2016/04/18/spinning-japanese-astronomy-satellite-may-be-beyond-saving/ |title=Attitude control failures led to break-up of Japanese astronomy satellite |work=Spaceflight Now |first=Stephen |last=Clark |date=18 April 2016 |accessdate=21 April 2016}}</ref>
|-
| November 2, 2016 06:20:00 || F31 || H2A 202 || {{flagicon|Japan}} [[Himawari 9]] ||{{Success}}
|-
| January 24, 2017 07:44:00 || F32 || H2A 204 || {{flagicon|Japan}} [[DSN-2]] (Kirameki 2) || {{Success}}
|-
| March 17, 2017 01:20:00 || F33 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 5 || {{Success}}
|-
| June 1, 2017 00:17:46 || F34 || H2A 202 || {{flagicon|Japan}} [[QZS-2]] (Michibiki 2) || {{Success}}
|-
| August 19, 2017 05:29:00 || F35 || H2A 204 || {{flagicon|Japan}} [[QZS-3]] (Michibiki 3) || {{Success}}
|-
| October 9, 2017 22:01:37 || F36 || H2A 202 || {{flagicon|Japan}} [[QZS-4]] (Michibiki 4) || {{Success}}
|-
| December 23, 2017 01:26:22 || F37 || H2A 202 || {{flagicon|Japan}} [[GCOM-C]] (Shikisai) {{flagicon|Japan}} [[SLATS]] (Tsubame) || {{Success}}
|-
| February 27, 2018 04:34:00 || F38 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 6 || {{Success}}
|-
| June 12, 2018 04:20:00 || F39 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 6 || {{Success}}
|-
| October 29, 2018 04:08:00 || F40 || H2A 202 || {{flagicon|Japan}} [[GOSAT-2]] (Ibuki-2) || {{Success}}
|-
|}

==See also==
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]

== References ==
'''Notes'''
{{Reflist|30em}}

'''Sources'''
{{Refbegin}}
* {{Cite web|title=Japan Prepares for Crucial Rocket Launch|work=SPACE.com|url=http://www.space.com/missionlaunches/ap_jaxa_h2a_050209.html|accessdate=16 February 2005 }}
* {{Cite web|title=H-IIA Expendable Launch Vehicle|work=SPACEandTECH|url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|accessdate=February 16, 2005|deadurl=yes|archiveurl=https://www.webcitation.org/64qmrxW1D?url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|archivedate=January 21, 2012|df=}}
{{Refend}}

==External links==
{{commons category|H-IIA}}
* [http://h2a.mhi.co.jp/en/ H-IIA LAUNCH SERVICES], Mitsubishi Heavy Industries
* [http://www.jaxa.jp/projects/rockets/h2a/index_e.html JAXA H-IIA English page]
* [https://web.archive.org/web/20070321160909/http://www.jaxa.jp/index_e.html JAXA English page]
* [http://www.jaxa.jp/projects/in_progress_e.html JAXA Launch Schedule]
* [http://www.jaxa.jp/about/centers/tnsc/index_e.html Tanegashima Space Center]
* [https://web.archive.org/web/20050404015815/http://visit.jaxa.jp/tanegashima/index_e.html "Tanegashima Space Center"– VISIT JAXA --]
* [https://web.archive.org/web/20041015211458/http://www.astronautix.com/lvs/h2a.htm Encyclopedia Astronautica page]
* [http://spaceflightnow.com/h2a/f6/ Failed Launch, 11-29-2003]
* [http://www.spaceflightnow.com/h2a/f2/020201rocket.html Image]
* [http://www.spaceflightnow.com/h2a/f3/020908rocket.html Launch 2 Image]

{{Mitsubishi Heavy Industries}}
{{Expendable launch systems}}
{{Japanese launch systems}}

{{DEFAULTSORT:H-Iia}}
[[Category:Expendable space launch systems]]
[[Category:Mitsubishi Heavy Industries space launch vehicles]]
[[Category:Vehicles introduced in 2001]]

[[de:H-II#H-IIA]]

H-IIA

2018-11-05T23:14:49Z

Blastr42: /* Launch history */

{{Other uses|H2A (disambiguation)}}

{{Infobox rocket
|name =H-IIA
|image =H IIA No. F23 with GPM on its way to the launchpad.jpg
|imsize = 300
|caption = H-IIA No. F23 rolls out to the launch pad in February 2014
|function = [[Medium-lift launch vehicle]]
|manufacturer = {{plainlist|
* [[Mitsubishi Heavy Industries]] (prime)
* [[Alliant Techsystems|ATK]] (sub)
}}
|country-origin = [[Japan]]
|cpl-year =
|cpl = {{US$|90 million[http://www.gao.gov/products/GAO-17-609]}}
|height = {{cvt|53|m}}
|diameter = {{cvt|4|m}}
|mass = {{cvt|285,000-445,000|kg}}
|stages = 2
|family = [[H-II (rocket family)|H-II]]
|derivatives = [[H-IIB]]
|capacities = 
{{Infobox rocket/payload
|location = [[Low Earth orbit|LEO]] 
|kilos = {{cvt|10,000-15,000|kg}} 
}}
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]] 
|kilos = {{cvt|4,100-6,000|kg}} 
}}

|status = Active
|sites = [[Tanegashima Space Center|Tanegashima]] [[Yoshinobu Launch Complex|LA-Y]]
|first = {{plainlist|
* '''202:''' 29 August 2001
* '''204:''' 18 December 2006
* '''2022:''' 26 February 2005
* '''2024:''' 4 February 2002
}}
|last = {{plainlist|
* '''202:''' 12 June 2018
* '''204:''' 19 August 2017
* '''2022:''' 14 September 2007
* '''2024:''' 23 February 2008
}}
|launches = {{flatlist|
* 39
** '''202:''' 25
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 7
}}
|success = {{flatlist|
* 38
** '''202:''' 25
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 6
}}
|fail =1 ('''2024''')
|partial =
|other =
|payloads = {{flatlist|
* [[SELENE]]
* [[Greenhouse Gases Observing Satellite|Ibuki]]
* [[Akatsuki (probe)|Akatsuki]]
}}


|stagedata =
{{Infobox rocket/stage
|type = booster 
|diff = All variants 
|stageno = 
|name = [[SRB-A]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|2,260|kN}} 
|total = {{cvt|4,520–9,040|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 120 seconds 
|fuel = [[HTPB]] 
}}
{{Infobox rocket/stage
|type = booster 
|diff = 2022 / 2024 
|stageno = 
|name = [[Castor (rocket stage)|Castor 4A-XL]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|745|kN}} 
|total = {{cvt|1,490–2,980|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 60 seconds 
|fuel = [[Solid rocket|Solid]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = First 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-7A]] 
|solid = 
|thrust = {{cvt|1,098|kN}} 
|total = 
|SI = {{convert|440|isp}} 
|burntime = 390 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = Second 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-5B]] 
|solid = 
|thrust = {{cvt|137|kN}} 
|total = 
|SI = {{convert|447|isp}} 
|burntime = 534 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
}}
[[Image:H-IIA F19 launching IGS-O4.jpg|right|250px|thumb|Liftoff of H-IIA Flight 19]]
[[Image:H-IIA Family.png|right|250px|thumb|H-IIA rocket lineup]]
[[Image:H-IIA-Launch-Vehicle.png|thumb|80px|H-IIA]]

'''H-IIA''' ('''H2A''') is an active [[expendable launch system]] operated by [[Mitsubishi Heavy Industries]] (MHI) for the [[JAXA|Japan Aerospace Exploration Agency]]. The liquid-fueled H-IIA [[rocket]]s have been used to launch [[satellite]]s into [[geostationary orbit]], to launch a lunar orbiting spacecraft, and to launch ''[[Akatsuki (spacecraft)|Akatsuki]]'', which studied the planet Venus. Launches occur at the [[Tanegashima Space Center]]. The H-IIA first flew in 2001. {{As of|December 2017}}, H-IIA rockets were launched 37 times, including 31 consecutive missions without a failure, dating back to November 29, 2003.

Production and management of the H-IIA shifted from JAXA to MHI on April 1, 2007. Flight 13, which launched the lunar orbiter [[SELENE]], was the first H-IIA launched after this privatization.<ref>{{cite web|url=http://www.satnews.com/stories2007/4356/ |title=Mitsubishi and Arianespace Combine Commercial Satellite Launch Services |publisher=SatNews |deadurl=yes |archiveurl=https://web.archive.org/web/20120208014829/http://www.satnews.com/stories2007/4356/ |archivedate=February 8, 2012 }}</ref>

The H-IIA is a derivative of the earlier [[H-II]] rocket, substantially redesigned to improve reliability and minimize costs. There are currently two (formerly four) different variants of the H-IIA in active service for various purposes. A derivative design, the [[H-IIB]], was developed in the 2000s and made its [[maiden flight]] in 2009.

== Vehicle description ==
The launch capability of an H-IIA launch vehicle can be enhanced by adding [[SRB-A]] ([[solid rocket booster]] or SRB) and [[Castor (rocket stage)|Castor 4AXL]] (solid strap-on booster or SSB) to its basic configuration, creating a "family". The models are indicated by three or four numbers following the prefix "H2A". The first number in the sequence indicates the number of stages; the second number of [[liquid rocket booster]]s (LRBs); the third number of SRBs; and, if present, the fourth number shows the number of SSBs.<ref name="leaflet">{{cite web |url=http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |title=H-IIA Launch Vehicle |accessdate=2007-09-15 |format=PDF |publisher=JAXA |pages=2 |deadurl=yes |archiveurl=https://web.archive.org/web/20080228013323/http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |archivedate=2008-02-28 |df= }}</ref> The first two figures are virtually fixed at "20", as H-IIA is always two-staged, and the plans for LRBs were cancelled and superseded by the [[H-IIB]].

== Variants ==

{| class="wikitable"
|-
! Designation!!Mass (tonnes)!!Payload (tonnes to [[Geostationary transfer orbit|GTO]])!!Addon modules
|-
| H2A 202||285||4.1||2 [[SRB-A]] (SRB)
|-
| H2A 2022 (discontinued)<ref>[https://web.archive.org/web/20070105140945/http://www.nikkei.co.jp/news/sangyo/20061205AT1D0300504122006.html 三菱重工、「H2A」2機種に半減・民営化でコスト減]. NIKKEI NET</ref>||316||4.5||2 SRB-A (SRB) + 2 [[Castor (rocket stage)|Castor 4AXL]] (SSB)
|-
| H2A 2024 (discontinued)||347||5||2 SRB-A (SRB) + 4 Castor 4AXL (SSB)
|-
| H2A 204||445||6||4 SRB-A (SRB)
|-
| H2A 212 (cancelled)||403||7.5||2 SRB-A (SRB) + 1 LRB
|-
| H2A 222 (cancelled)||520||9.5||2 SRB-A (SRB) + 2 LRBs
|}

== Launch history ==
{{main|List of H-I and H-II launches}}

The first H-IIA was successfully launched on August 29, 2001, followed by a string of successes.

The sixth launch on November 29, 2003, intended to launch two [[Information Gathering Satellite|IGS]] [[reconnaissance satellite]]s, failed. JAXA announced that launches would resume in 2005, and the first successful flight took place on February 26 with the launch of [[Multi-Functional Transport Satellite|MTSAT-1R]].

The first launch for a mission beyond Earth orbit was on September 14, 2007 for the [[SELENE]] moon mission. The first foreign payload on the H-IIA was the Australian FedSat-1 in 2002. As of March 2015, 27 out of 28 launches were successful.

A rocket with increased launch capabilities, [[H-IIB]], is a derivative of the H-IIA family. H-IIB uses two LE-7A engines in its first stage, as opposed to one in H-IIA. The first H-IIB was successfully launched on September 10, 2009.

For the 29th flight on November 24, 2015, an H-IIA with an upgraded second stage<ref>{{Cite web |url=http://global.jaxa.jp/press/2015/11/20151124_h2af29.html|title=Launch Result of Telstar 12 VANTAGE by H-IIA Launch Vehicle No. 29|publisher=JAXA|date=24 Nov 2015|accessdate=30 Nov 2015}}</ref> launched the Canadian Telstar 12V satellite, the first commercial primary payload for a Japanese launch vehicle.<ref>{{Cite web |url=http://www.nasaspaceflight.com/2015/11/japanese-h-iia-telstar-12v-launch/|title=Japanese H-IIA successfully lofts Telstar 12V|publisher=NASASpaceflight.com|author=William Graham|date=23 Nov 2015|accessdate=30 Nov 2015}}</ref>

{| class="wikitable"
!Date ([[UTC]]) !! Flight !! Type !! Payload(s) !! Outcome
|-
| August 29, 2001 07:00:00 || TF1 || H2A 202|| {{flagicon|Japan}} VEP 2 {{flagicon|Japan}} LRE || {{Success}}
|-
| February 4, 2002 02:45:00 || TF2 || H2A 2024 || {{flagicon|Japan}} VEP 3 {{flagicon|Japan}} [[MDS-1]] (Tsubasa) {{flagicon|Japan}} DASH || {{Success}}
|-
| September 10, 2002 08:20:00 || F3 || H2A 2024 || {{flagicon|Japan}} [[USERS]] {{flagicon|Japan}} [[DRTS]] (Kodama) || {{Success}}
|-
| December 14, 2002 01:31:00 || F4 || H2A 202 || {{flagicon|Japan}} [[ADEOS 2]] (Midori 2) {{flagicon|Japan}} WEOS (Kanta-kun) {{flagicon|Australia}} [[FedSat]] 1 {{flagicon|Japan}} Micro LabSat 1 || {{Success}}
|-
| March 28, 2003 01:27:00 || F5 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 1 {{flagicon|Japan}} IGS-Radar 1 || {{Success}}
|-
| rowspan=2 | {{nobr|November 29, 2003}} 04:33:00 || rowspan=2 | F6 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical (2) {{flagicon|Japan}} IGS-Radar (2) || {{Failure}}
|-
| colspan=3 style="background:linen;" | A hot gas leak from one SRB-A motor destroyed its separation system. The strap-on did not separate as planned, and the weight of the spent motor prevented the vehicle from achieving its planned height.<ref>{{cite web |url=http://www.jaxa.jp/press/2003/11/20031129_h2af6_e.html |title=Launch Result of IGS #2/H-IIA F6 |date=November 29, 2003 |accessdate=June 19, 2013 |publisher=JAXA}}</ref>
|-
| February 26, 2005 09:25:00 || F7 || H2A 2022 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-1R]] (Himawari 6) || {{Success}}
|-
| January 24, 2006 01:33:00 || F8 || H2A 2022 || {{flagicon|Japan}} [[ALOS]] (Daichi) || {{Success}}
|-
| February 18, 2006 06:27:00 || F9 || H2A 2024 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-2]] (Himawari 7) || {{Success}}
|-
| September 11, 2006 04:35:00 || F10 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 2 || {{Success}}
|-
| December 18, 2006 06:32:00 || F11 || H2A 204 || {{flagicon|Japan}} [[ETS-VIII]] (Kiku 8) || {{Success}}
|-
| February 24, 2007 04:41:00 || F12 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 2 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3V || {{Success}}
|-
| September 14, 2007 01:31:01 || F13 || H2A 2022 || {{flagicon|Japan}} [[SELENE]] (Kaguya) || {{Success}}
|-
| February 23, 2008 08:55:00 || F14 || H2A 2024 || {{flagicon|Japan}} [[WINDS]] (Kizuna) || {{Success}}
|-
| January 23, 2009 03:54:00 || F15 || H2A 202 || {{flagicon|Japan}} [[GOSAT]] (Ibuki) {{flagicon|Japan}} [[SDS-1]] {{flagicon|Japan}} STARS (Kūkai) {{flagicon|Japan}} KKS-1 (Kiseki) {{flagicon|Japan}} PRISM (Hitomi) {{flagicon|Japan}} [[Sohla]]-1 (Maido 1) {{flagicon|Japan}} SORUNSAT-1 (Kagayaki) {{flagicon|Japan}} SPRITE-SAT (Raijin) || {{Success}}<ref>{{cite web |url=http://www.jaxa.jp/press/2009/01/20090123_h2a-f15_e.html |title=Launch Result of the IBUKI (GOSAT) by H-IIA Launch Vehicle No. 15 |date=January 23, 2009 |publisher=MHI and JAXA}}</ref>
|-
| November 28, 2009 01:21:00 <ref>{{cite web|url=http://www.sorae.jp/030801/3328.html|title=H-IIA F16|publisher=Sorae|deadurl=yes|archiveurl=https://www.webcitation.org/64qmnLLfk?url=http://www.sorae.jp/030801/3328.html|archivedate=2012-01-21|df=}}</ref> || F16 || H2A 202|| {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3|| {{Success}}
|-
| May 20, 2010 21:58:22<ref>{{cite web |url=http://www.jaxa.jp/press/2010/03/20100303_h2af17_e.html |title=Launch Day of the H-IIA Launch Vehicle No. 17 |date=March 3, 2010 |publisher=JAXA}}</ref><ref>{{cite web |url=http://www.jaxa.jp/countdown/f17/overview/sub_payload_e.html |title=Overview of Secondary Payloads |publisher=JAXA}}</ref><ref>{{Cite web |url=http://www.space.com/missionlaunches/japan-venus-probe-launch-thursday-100518.html|title=New Venus Probe to Launch Thursday From Japan After|publisher=space.com|author=Tariq Malik|date=18 May 2010|accessdate=20 May 2010}}</ref> || F17 || H2A 202<ref name="nasa_f17">{{Cite web|url=http://www.nasaspaceflight.com/2010/05/axa-launch-h-iia-carrying-akatsuki-ikaros/|title=JAXA launch H-IIA carrying AKATSUKI and IKAROS scrubbed|author=Chris Bergin|date=17 May 2010|accessdate=17 May 2010|publisher=NASASpacflight.com}}</ref> || {{flagicon|Japan}} [[PLANET-C]] (Akatsuki) {{flagicon|Japan}} [[IKAROS]] {{flagicon|Japan}} [[UNITEC-1]] (Shin'en) {{flagicon|Japan}} [[Waseda-SAT2]] {{flagicon|Japan}} [[K-Sat]] (Hayato) {{flagicon|Japan}} [[Negai (satellite)|Negai☆″]]|| {{Success}}
|-
| September 11, 2010 11:17:00<ref>{{cite web |url=http://www.jaxa.jp/press/2010/08/20100804_michibiki_e.html |title=New Launch Day of the First Quasi-Zenith Satellite 'MICHIBIKI' by H-IIA Launch Vehicle No. 18 |publisher=JAXA}}</ref> || F18 || H2A 202 || {{flagicon|Japan}} [[Quasi-Zenith Satellite System|QZS-1]] (Michibiki) || {{Success}}
|-
| September 23, 2011 04:36:50<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/09/japanese-h-2a-launches-new-igs-military-satellite/|title=Japanese H-2A launches with new IGS military satellite |author=Chris Bergin|date=23 September 2011 |publisher= NASASpaceflight.com}}</ref> || F19 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 4 || {{Success}}
|-
| December 12, 2011 01:21:00<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/12/japanese-h-2a-lofts-igs-radar-3-satellite-into-orbit/ |author=Chris Bergin|date=11 December 2011 |publisher= NASASpaceflight.com|title=Japanese H-2A lofts IGS (Radar-3) satellite into orbit}}</ref> || F20 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 3 || {{Success}}
|-
| May 17, 2012 16:39:00 || F21 || H2A 202<ref>{{cite web |url=http://h2a.mhi.co.jp/en/f21/overview/index.html |title=Launch Overview – H-IIA Launch Services Flight No.21 |accessdate=April 15, 2012 |publisher=Mitsubishi Heavy Industries}}</ref> || {{flagicon|Japan}} [[GCOM-W]]1 (Shizuku) {{flagicon|South Korea}} [[KOMPSAT-3]] (Arirang 3) {{flagicon|Japan}} [[SDS-4]] {{flagicon|Japan}} [[HORYU-2]] || {{Success}}
|-
| January 27, 2013 04:40:00 || F22 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 4 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5V|| {{Success}}
|-
| February 27, 2014 18:37:00 || F23 || H2A 202 || {{flagicon|Japan}} {{flagicon|USA}} [[Global Precipitation Measurement|GPM-Core]] {{flagicon|JPN}} SindaiSat (Ginrei) {{flagicon|JPN}} STARS-II (Gennai) {{flagicon|JPN}} TeikyoSat-3 {{flagicon|JPN}} ITF-1 (Yui) {{flagicon|JPN}} OPUSAT (CosMoz) {{flagicon|JPN}} INVADER {{flagicon|JPN}} KSAT2|| {{Success}}
|-
| May 24, 2014 03:05:14 || F24 || H2A 202 || {{flagicon|Japan}} [[ALOS-2]] (Daichi 2) {{flagicon|JPN}} [[RISING-2]] {{flagicon|JPN}} [[UNIFORM-1]] {{flagicon|JPN}} [[SOCRATES (satellite)|SOCRATES]] {{flagicon|JPN}} SPROUT|| {{Success}}
|-
| October 7, 2014 05:16:00 || F25 || H2A 202 || {{flagicon|Japan}} [[Himawari 8]] || {{Success}}
|-
| December 3, 2014 04:22:04 || F26 || H2A 202 || {{flagicon|Japan}} [[Hayabusa 2]] {{flagicon|Japan}} [[Shin'en 2]] {{flagicon|Japan}} ARTSAT2-DESPATCH {{flagicon|Japan}} [[PROCYON]]|| {{Success}}
|-
| February 1, 2015 01:21:00 || F27 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar Spare|| {{Success}}
|-
| March 26, 2015 01:21:00 || F28 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5|| {{Success}}
|-
| November 24, 2015 06:50:00 || F29 || H2A 204 || {{flagicon|Canada}} [[Telstar 12V|Telstar 12 Vantage]] ||{{Success}}
|-
| rowspan=2 | February 17, 2016 08:45:00 || rowspan=2 | F30 || H2A 202 || {{flagicon|Japan}} [[ASTRO-H]] (Hitomi) {{flagicon|Japan}} ChubuSat-2 (Kinshachi 2) {{flagicon|Japan}} ChubuSat-3 (Kinshachi 3) {{flagicon|Japan}} Horyu-4 ||{{Success}}
|-
| colspan=3 style="background:linen;" | The Hitomi telescope broke apart 37 days after launch.<ref name="clark-20160418">{{cite news |url=http://spaceflightnow.com/2016/04/18/spinning-japanese-astronomy-satellite-may-be-beyond-saving/ |title=Attitude control failures led to break-up of Japanese astronomy satellite |work=Spaceflight Now |first=Stephen |last=Clark |date=18 April 2016 |accessdate=21 April 2016}}</ref>
|-
| November 2, 2016 06:20:00 || F31 || H2A 202 || {{flagicon|Japan}} [[Himawari 9]] ||{{Success}}
|-
| January 24, 2017 07:44:00 || F32 || H2A 204 || {{flagicon|Japan}} [[DSN-2]] (Kirameki 2) || {{Success}}
|-
| March 17, 2017 01:20:00 || F33 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 5 || {{Success}}
|-
| June 1, 2017 00:17:46 || F34 || H2A 202 || {{flagicon|Japan}} [[QZS-2]] (Michibiki 2) || {{Success}}
|-
| August 19, 2017 05:29:00 || F35 || H2A 204 || {{flagicon|Japan}} [[QZS-3]] (Michibiki 3) || {{Success}}
|-
| October 9, 2017 22:01:37 || F36 || H2A 202 || {{flagicon|Japan}} [[QZS-4]] (Michibiki 4) || {{Success}}
|-
| December 23, 2017 01:26:22 || F37 || H2A 202 || {{flagicon|Japan}} [[GCOM-C]] (Shikisai) {{flagicon|Japan}} [[SLATS]] (Tsubame) || {{Success}}
|-
| February 27, 2018 04:34:00 || F38 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 6 || {{Success}}
|-
| June 12, 2018 04:20:00 || F39 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 6 || {{Success}}
|-
| October 29, 2018 04:08:00 || F40 || H2A 202 || {{flagicon|Japan}} [[GOSAT-2]] (Ibuki-2) || {{Success}}
|-
|}

==See also==
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]

== References ==
'''Notes'''
{{Reflist|30em}}

'''Sources'''
{{Refbegin}}
* {{Cite web|title=Japan Prepares for Crucial Rocket Launch|work=SPACE.com|url=http://www.space.com/missionlaunches/ap_jaxa_h2a_050209.html|accessdate=16 February 2005 }}
* {{Cite web|title=H-IIA Expendable Launch Vehicle|work=SPACEandTECH|url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|accessdate=February 16, 2005|deadurl=yes|archiveurl=https://www.webcitation.org/64qmrxW1D?url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|archivedate=January 21, 2012|df=}}
{{Refend}}

==External links==
{{commons category|H-IIA}}
* [http://h2a.mhi.co.jp/en/ H-IIA LAUNCH SERVICES], Mitsubishi Heavy Industries
* [http://www.jaxa.jp/projects/rockets/h2a/index_e.html JAXA H-IIA English page]
* [https://web.archive.org/web/20070321160909/http://www.jaxa.jp/index_e.html JAXA English page]
* [http://www.jaxa.jp/projects/in_progress_e.html JAXA Launch Schedule]
* [http://www.jaxa.jp/about/centers/tnsc/index_e.html Tanegashima Space Center]
* [https://web.archive.org/web/20050404015815/http://visit.jaxa.jp/tanegashima/index_e.html "Tanegashima Space Center"– VISIT JAXA --]
* [https://web.archive.org/web/20041015211458/http://www.astronautix.com/lvs/h2a.htm Encyclopedia Astronautica page]
* [http://spaceflightnow.com/h2a/f6/ Failed Launch, 11-29-2003]
* [http://www.spaceflightnow.com/h2a/f2/020201rocket.html Image]
* [http://www.spaceflightnow.com/h2a/f3/020908rocket.html Launch 2 Image]

{{Mitsubishi Heavy Industries}}
{{Expendable launch systems}}
{{Japanese launch systems}}

{{DEFAULTSORT:H-Iia}}
[[Category:Expendable space launch systems]]
[[Category:Mitsubishi Heavy Industries space launch vehicles]]
[[Category:Vehicles introduced in 2001]]

[[de:H-II#H-IIA]]

Vulcan Centaur

2018-10-11T23:22:38Z

Blastr42:

{{hatnote|This article is about the proposed American Vulcan launch vehicle. Not to be confused with the Russian [[Vulkan-Hercules]] concept launch vehicle or the European [[Vulcain]] rocket engine. For other uses, see [[Vulcan (disambiguation)|Vulcan]].}}
{{Infobox rocket
|name = Vulcan
|image = ULA_Vulcan20180927.jpg
|caption = A simulated expanded view of the 562-configuration Vulcan Centaur rocket.
|function = Partly-reusable [[launch vehicle]]
|manufacturer = [[United Launch Alliance]]
|country-origin = United States
|height = {{convert|58.3|m|ft|abbr=on}}
|diameter = {{convert|5.4|m|ft|abbr=on}}<ref>{{cite web|last1=Peller|first1=Mark|title=United Launch Alliance|url=http://www.ispcs.com/content/files/Mark%20Peller.pdf|accessdate=2016-03-30|archive-url=https://web.archive.org/web/20160412062627/http://www.ispcs.com/content/files/Mark%20Peller.pdf|archive-date=2016-04-12|dead-url=yes|df=}}</ref>
|mass ={{convert|546,700|kg|lbs|abbr=on}}
|stages = 2

|capacities =
{{Infobox rocket/payload
|location = [[Low Earth Orbit|LEO]]
|kilos = {{cvt|56000|lb|order=flip}}<ref name=ULA20180927>{{cite web |title=United Launch Alliance Building Rocket of the Future with Industry-Leading Strategic Partnerships ULA Selects Blue Origin Advanced Booster Engine for Vulcan Centaur Rocket System |url=https://www.ulalaunch.com/about/news/2018/09/27/united-launch-alliance-building-rocket-of-the-future-with-industry-leading-strategic-partnerships |publisher=United Launch Alliance |date=27 September 2018}}</ref>(Vulcan Heavy [[Centaur V|Centaur]])}}

{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = {{cvt|33000|lb|order=flip}}<ref name=ULA20180927 />(Vulcan Heavy [[Centaur V|Centaur]])}}

{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = {{cvt|16000|lb|order=flip}}<ref name=ULA20180927 />(Vulcan Heavy [[Centaur V|Centaur]])}}
|comparable = {{flatlist|
* [[Ariane 5]]
* [[Atlas V]]
* [[Delta IV Heavy]]
* [[Falcon Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Omega_(rocket)|OmegA]]
* [[Saturn C-3]]
}}
|status = In development
|sites = [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 41|SLC-41]] [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 3|SLC-3E]]<ref name="sn20151012">{{cite news |last1=Clark|first1=Stephen |title=ULA selects launch pads for new Vulcan rocket |url=http://spaceflightnow.com/2015/10/12/ula-selects-launch-pads-for-new-vulcan-rocket/ |accessdate=12 October 2015 |work=Spaceflight Now |date=12 October 2015}}</ref>
|launches =
|success =
|fail =
|partial =
|first= Mid-2020 (planned)<ref name=ULA20180927 />
|last=
|stagedata = 
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name =
|number = 0–6
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = GEM 63XL<ref>{{cite web|last1=Rhian|first1=Jason|title=ULA selects Orbital ATK's GEM 63/63XL SRBs for Atlas V and Vulcan Boosters|url=http://www.spaceflightinsider.com/organizations/ula/ula-selects-orbital-atks-gem-6363-xl-srbs-for-atlas-v-and-vulcan-boosters/|website=Spaceflight Insider|accessdate=2015-09-25}}</ref>
|solid = yes
|thrust = {{convert|2201.7|kN|abbr=on}}
|total = 
|SI = 
|burntime = 
|fuel = [[HTPB]]
}}
{{Infobox rocket/stage
|type = stage
|diff = 
|stageno = First
|name = 
|number = 
|length = 
|diameter = {{convert|5.4|m|abbr=on}}
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 2× [[BE-4]]
|solid = 
|thrust = {{convert|1100000|lb-f|kN|order=flip|lk=in|abbr=on}}
|total = 
|SI = 
|burntime = 
|fuel = [[Liquid methane|CH4]] / [[Liquid oxygen|LOX]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name = [[Centaur (rocket stage)|Centaur]] (initial flights, late-2010s)
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 2× [[RL10]]-C<ref>{{cite tweet |user=ulalaunch |number=1045406241131032576 |date=27 September 2018 |title=Our partnerships w/ @BlueOrigin as well as @AerojetRDyne @NorthropGrumman L-3 Avionics & @RUAGSpace will allow this next-gen American rocket to affordably transform the future of space launch! }}</ref><ref>{{Cite web|url=https://www.ulalaunch.com/rockets/vulcan-centaur|title=Vulcan Centaur|website=United Launch Alliance|language=en|access-date=2018-10-02}}</ref><ref>{{cite web|title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine for Next-generation Vulcan Centaur Upper Stage|url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage|website=United Launch Alliance website|accessdate=11 May 2018}}</ref>
|solid = 
|thrust = {{convert|207.6|kN|lb-f|lk=in|abbr=on}}{{citation needed|date=February 2018}}
|total = 
|SI = {{convert|448.5|isp}}
|burntime = 
|fuel = [[Liquid hydrogen|LH2]] / [[Liquid oxygen|LOX]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name = [[Advanced Cryogenic Evolved Stage|ACES]] (proposed, mid-2020s)
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 4× [[RL10]]-C or 1× [[BE-3]] engine (TBC)
|solid = 
|thrust = 
|total = 
|SI = 
|burntime = 
|fuel = [[Liquid hydrogen|LH2]] / [[Liquid oxygen|LOx]]
}}
}}

The '''''Vulcan''''' rocket, also known as the '''''Vulcan Centaur''''',<ref name=sn20180325/> is an American heavy-payload [[launch vehicle]] under [[new product development|development]] since 2014 by [[United Launch Alliance]] (ULA), funded by a [[public–private partnership]] with the [[Federal government of the United States|U.S. government]]. ULA expects the [[maiden flight|first launch]] of the new rocket to occur no earlier than mid-2020.<ref name=SpaceNewsFoust201801>{{cite tweet |user=jeff_foust |number=954054070821670912 |title=Tom Tshudy, ULA: with Vulcan we plan to maintain reliability and on-time performance of our existing rockets, but at a very affordable price. First launch mid-2020. |date=18 January 2018}}</ref>

Through the first several years of the development project, the ULA board of directors had made only short-term (quarterly) funding commitments to the rocket program, and it remains unclear if long-term private funding will be available to finish the project. {{As of|2018|10}}, the US government had committed approximately {{USD|1.2 billion}} to Vulcan development.<ref name=sn20160310/><ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

== History ==
United Launch Alliance had considered several launch vehicle concepts in the decade since the company was formed in 2006. Various concepts for derivative vehicles based on the [[Atlas (rocket)|Atlas]] and [[Delta (rocket)|Delta]] lines of launch vehicles they inherited from their predecessor companies were presented to the U.S. government for funding. None were funded beyond concept stage.

In early 2014, geopolitical and [[Federal government of the United States|U.S.]] political considerations involving [[international sanctions during the Ukrainian crisis]], led to an effort by ULA to consider possibly replacing the Russian-supplied [[RD-180]] engine used on the first stage booster of the [[Atlas V]]. Formal study contracts were issued by ULA in June 2014 to several U.S. rocket engine suppliers.<ref name="sn20140917" /> ULA was also facing competition from [[SpaceX]], then seen to affect ULA's core national security market of U.S. military launches, and by July 2014 the [[United States Congress]] was debating whether to legislate a ban on future use of the RD-180.<ref name="sn20150424">{{cite news |last1=Gruss|first1=Mike |title=Evolution of a Plan : ULA Execs Spell Out Logic Behind Vulcan Design Choices |url=http://spacenews.com/evolution-of-a-plan-ula-execs-spell-out-logic-behind-vulcan-design-choices/ |work=Space News |date=2015-04-24 |accessdate=25 April 2015}}</ref>

=== New first stage booster ===
In September 2014, ULA announced that it had entered into a partnership with [[Blue Origin]] to develop the [[BE-4]] [[liquid oxygen]] (LOX) and [[liquid methane]] (CH4) engine to replace the RD-180 on a new first stage [[Booster (rocketry)|booster]]. The Blue engine was already in its third year of development by Blue Origin, and ULA said it expected the new stage and engine to start flying no earlier than 2019.<ref name="dd20150207" /> Two of the {{convert|550000|lbf|kN|order=flip|adj=on|lk=on}}-thrust BE-4 engines were to be used on a new launch vehicle booster.<ref name="sn20140917">{{cite news |last1=Ferster|first1=Warren |title=ULA To Invest in Blue Origin Engine as RD-180 Replacement |url=http://www.spacenews.com/article/launch-report/41901ula-to-invest-in-blue-origin-engine-as-rd-180-replacement |date=2014-09-17 |work=Space News |access-date=2014-09-19}}</ref> ULA referred to the successor concept vehicle as a "next generation launch system"<ref name="dbj20141016" /> and used that descriptor into early 2015.<ref name="dd20150207">{{cite news |last1=Fleischauer|first1=Eric |title=ULA's CEO talks challenges, engine plant plans for Decatur |url=http://www.decaturdaily.com/news/ula-s-ceo-talks-challenges-engine-plant-plans-for-decatur/article_8ba49046-af4a-11e4-97ef-ff58591d43fc.html |work=Decatur Daily |date=7 February 2015 |accessdate=2015-04-17}}</ref>

In October 2014, ULA announced a major restructuring of company processes and workforce to reduce launch costs by half. One of the reasons given for the restructuring and new cost reduction goals was [[Space launch market competition|new competition in the launch market]] from SpaceX.<ref name="dbj20141016" /><ref name="sn20150424" /> ULA planned to have preliminary design ideas in place for a blending of its existing Atlas V and [[Delta IV]] technologies by the end of 2014, to build a successor to the Atlas V that would allow the company to halve Atlas V launch costs.<ref name="dbj20141016">{{cite news |last1=Avery|first1=Greg |title=ULA plans new rocket, restructuring to cut launch costs in half |url=http://www.bizjournals.com/denver/blog/boosters_bits/2014/10/exclusive-ula-plans-a-new-rocket-restructuring-to.html |accessdate=2015-04-17 |work=Denver Business Journal |date=2014-10-16}}</ref> A part of the restructuring effort was described as the effort to co-develop the alternative BE-4 engine with Blue Origin for the new launch vehicle.<ref name="spo20141114">{{cite news |last1=Delgado|first1=Laura M. |title=ULA's Tory Bruno Vows To Transform Company |url=http://www.spacepolicyonline.com/news/ulas-tory-bruno-vows-to-transform-company |accessdate=2015-04-17 |work=SpacePolicyOnline.com |date=2014-11-14}}</ref>

=== Unveiling ===
On 13 April 2015, CEO [[Tory Bruno]] unveiled the new ULA launch vehicle as the ''Vulcan'' at the 31st [[Space Symposium]], a new [[two-stage-to-orbit]] (TSTO) rocket that would be rolled out incrementally. The Vulcan name was chosen after an online poll to select the name. [[Vulcan Inc.]] stated that it held the trademark on the name and contacted ULA.<ref name="nbc20150413">{{cite news |last1=Boyle |first1=Alan |url=http://www.nbcnews.com/science/space/united-launch-alliance-boldly-names-its-next-big-rocket-vulcan-n340881 |work=NBC |title=United Launch Alliance Boldly Names Its Next Rocket: Vulcan! |date=2015-04-13 |accessdate=2015-04-17}}</ref>{{update after|2018|5|13}} ULA stated its goal was to sell a "barebones Vulcan" for half the [[price]] of a basic Atlas V rocket, which sold for about $164 million {{asof|2015|lc=y}}. Addition of strap-on boosters for heavier satellites would increase the price.<ref name="sfn-20150422">{{cite news |url=http://spaceflightnow.com/2015/04/22/ula-needs-commercial-business-to-close-vulcan-rocket-business-case/ |title=ULA needs commercial business to close Vulcan rocket business case |first1=Stephen |last1=Clark |work=Spaceflight Now |date=22 April 2015 |accessdate=23 April 2015}}</ref> At the announcement, the ULA [[Board of directors|board]] had not yet approved the new launch vehicle, with first launch planned in 2019.<ref name="sn20150424" />

ULA put forth an "incremental approach" to rolling out the vehicle and its technologies,<ref name="sn20150413">{{cite news |last1=Gruss |first1=Mike |url=http://spacenews.com/ulas-vulcan-rocket-to-be-rolled-out-in-stages/ |work=SpaceNews |title=ULA’s Vulcan Rocket To be Rolled out in Stages |date=2015-04-13 |accessdate=2015-04-17}}</ref> with Vulcan deployment beginning with the first stage, based on the Delta IV's fuselage diameter and production process, expected to use two BE-4 engines. The [[Aerojet Rocketdyne#AR1|Aerojet Rocketdyne AR1 engine]] was retained by ULA as a contingency option. In late September 2018, ULA announced that the BE-4 engine was to power the first stage.<ref name=":0">{{Cite news|url=https://www.defensenews.com/newsletters/military-space-report/2018/09/27/ula-selects-blue-origin-engine-to-power-launch-vehicle/|title=ULA selects Blue Origin engine to power launch vehicle|last=Mehta|first=Aaron|date=2018-09-27|work=Defense News|access-date=2018-09-27|language=en-US}}</ref> The first stage will be able to optionally use from one to six [[solid rocket booster]]s (SRBs) for added liftoff thrust,<ref name=Apr2015>[http://www.ulalaunch.com/ula-unveils-americas-new-rocket-vulcan.aspx?title=United+Launch+Alliance+Unveils+America%E2%80%99s+New+Rocket+%E2%80%93+Vulcan%3a+Innovative+Next+Generation+Launch+System+will+Provide+Country%E2%80%99s+Most+Reliable%2c+Affordable+and+Accessible+Launch+Service United Launch Alliance Unveils America’s New Rocket – Vulcan: Innovative Next Generation Launch System will Provide Country’s Most Reliable, Affordable and Accessible Launch Service. April 2015]</ref> launch a heavier payload than the highest-rated Atlas V in the six-SRB configuration.

ULA announced a feature they could subsequently develop which would make the first stage partly reusable: allowing the engines to detach from the vehicle after [[main engine cutoff]], descend through the [[atmospheric reentry|atmosphere]] with a heat shield and parachute, being captured by a helicopter in mid-air.<ref name="nbc20150413" /> ULA estimated that reusing the engines in this way would reduce the cost of the first stage propulsion by 90%, where propulsion is 65% of the total first stage cost.<ref name="sfn20150414">{{cite news |last1=Ray|first1=Justin |url=http://spaceflightnow.com/2015/04/14/ula-chief-explains-reusability-and-innovation-of-new-rocket/ |title=ULA chief explains reusability and innovation of new rocket |work=Spaceflight Now |date=14 April 2015 |accessdate=2015-04-17}}</ref> Initial configurations of Vulcan were intended then to use the same [[Centaur (rocket stage)|Centaur upper stage]] as the Atlas V, with its existing [[RL10]] engines, while a later advanced cryogenic upper stage — called the ''[[Advanced Cryogenic Evolved Stage]]'' (ACES) — was conceptually planned for full development by ULA in the late 2010s. ACES would be LOX and [[liquid hydrogen]] (LH2) powered by one to four rocket engines yet to be selected, and would include the [[Integrated Vehicle Fluids]] technology that could allow much longer on-orbit life of the upper stage, measured in weeks rather than hours.<ref name="dp20150413">{{cite web |url=http://www.denverpost.com/business/ci_27905093/america-meet-vulcan-your-next-united-launch-alliance |title=America, meet Vulcan, your next United Launch Alliance rocket |work=Denver Post |date=2015-04-13 |accessdate=2015-04-17}}</ref><ref name="sn20150413" />

{{Anchor|Vulcan Heavy}}In May 2015, ULA released a chart showing a potential future Vulcan Heavy three-core launch vehicle concept with {{cvt|50000|lb|order=flip|adj=on}}-payload capacity to [[geostationary transfer orbit]], while a single-core Vulcan 561 with the ACES upper stage would have {{cvt|33200|lb|order=flip|adj=on}} capacity to the same orbit.<ref name="ula20150505">{{cite tweet |author=Tory Bruno |author-link=Tory Bruno |user=torybruno |number=595628488410963970 |title=ULA Full Spectrum Lift Capability |date=5 May 2015 |access-date=8 May 2015}}</ref>

In September 2015, ULA and Blue Origin announced an agreement to expand production capabilities to include the [[BE-4]] rocket engine then in development and test. However, ULA also reconfirmed that the decision on the BE-4 versus the AJR AR1 would not be made until late 2016, with maiden flight of Vulcan no earlier than 2019.<ref name="wsj20150910">{{cite news |url=https://www.wsj.com/articles/boeing-lockheed-differ-on-whether-to-sell-rocket-joint-venture-1441933638 |title=Boeing, Lockheed Differ on Whether to Sell Rocket Joint Venture |work=Wall Street Journal |date=10 September 2015 |accessdate=2015-09-12}}</ref>

=== Engine testing and design optimization ===
{{As of|2016|01}}, full-engine testing of the BE-4 was planned to begin prior to the end of 2016,<ref name="sn20160123b">{{cite news |last=Berger|first=Brian |url=http://spacenews.com/launch-land-repeat-blue-origin-posts-video-of-new-shepards-friday-flight/ |title=Launch. Land. Repeat: Blue Origin posts video of New Shepard’s Friday flight |work=SpaceNews |date=2016-01-23 |accessdate=2016-01-24 |quote=''Also this year, we’ll start full-engine testing of the BE-4''}}</ref>{{update after|2017}} while ULA was designing two versions of the Vulcan first stage, one using the BE-4 with a {{convert|5.4|m|ft|sp=us|abbr=on|adj=on}} outer diameter to support the less-dense [[liquid methane|methane]] fuel and an AR1 design with the same {{convert|3.81|m|ft|sp=us|abbr=on|adj=on}} diameter as Atlas V for the denser [[RP-1]] (kerosene) fuel.<ref name=sn20160316>{{cite news |last=de Selding|first=Peter B. |url=http://spacenews.com/ula-intends-to-lower-its-costs-and-raise-its-cool-to-compete-with-spacex/ |title=ULA intends to lower its costs, and raise its cool, to compete with SpaceX |work=[[SpaceNews]] |date=2016-03-16 |accessdate=2016-03-19 |quote=Methane rocket has a lower density so we have a 5.4 meter design outside diameter, while drop back to the Atlas V size for the kerosene AR1 version. ... Aerojet Rocketdyne AR1 ... haven't built any hardware yet ... additive manufacturing is revolutionizing complex casting ... Aerojet is investing a little bit of their own money. Primarily they are counting on the government's RPS (Rocket Propulsion System) contracts to drive the funding.}}</ref>

ULA completed the [[Preliminary Design Review]] (PDR) in March 2016 for one of the two parallel designs: the Vulcan/Centaur launch vehicle with dual Blue Origin BE-4 engines. The PDR "confirms that the design meets the requirements for the diverse set of missions it will support."<ref name=ula20160324>{{cite web |url=http://www.ulalaunch.com/ula-completes-Vulcan-Centaur-PDR.aspx |title=United Launch Alliance Completes Preliminary Design Review for Next-Generation Vulcan Centaur Rocket |deadurl=no |archiveurl= https://web.archive.org/web/20160325145546/http://www.ulalaunch.com/ula-completes-Vulcan-Centaur-PDR.aspx |archivedate=2016-03-25 |accessdate=2016-03-25}}</ref> In the event, BE-4 engine testing did not begin until 2017.<ref name=ars20171019/>

In April 2016, ULA CEO Tory Bruno stated that the company was targeting a complete launch services price of $99 million for base Vulcan with no solid rocket boosters.<ref name=reuters20160414>{{Cite news |url=https://www.reuters.com/article/us-space-ula-layoffs-idUSKCN0XB2HQ |title=United Launch Alliance to lay off up to 875 by end of 2017: CEO |date=2016-04-14 |newspaper=Reuters |access-date=2016-05-07}}</ref> Also the ULA team was to be reduced by about one quarter of its legacy workforce, or more than 800 employees, by end 2017 in order to better [[Space launch market competition|compete]] with SpaceX and Blue Origin offerings in the US launch market.<ref name=reuters20160414/>{{update after|2017}} In October 2017, ULA announced that [[Bigelow Aerospace]]'s [[B330]] would be flown on a Vulcan 562 configuration rocket rather than the previously planned [[Atlas V]].<ref name="ula20171017">{{cite press release |url=http://www.ulalaunch.com/bigelow-aerospace-and-ula-lunar-depot.aspx |title=Bigelow Aerospace and United Launch Alliance Announce Agreement to Place a B330 Habitat in Low Lunar Orbit |publisher=United Launch Alliance |date=October 17, 2017 |accessdate=January 18, 2018}}</ref>

A delay was announced in January 2018 pushing first launch back from 2019 to mid-2020.<ref name=SpaceNewsFoust201801/> Also announced was an upgrade to the Centaur second stage to include up to four RL10 engines, to be called [[Centaur V]].<ref>{{cite web |title=Vulcan Centaur |url=https://www.ulalaunch.com/rockets/vulcan-centaur |publisher=ULA |accessdate=16 February 2018}}</ref>{{better source|date=May 2018}} While a tri-core Vulcan Heavy with a payload of {{cvt|50000|lb|order=flip}} had been conceptualized in 2015,<ref name="ula20150505" /> ULA clarified that it would not build a multi-core configuration as the upgrades to the Centaur second stage would allow a single core Vulcan Centaur to lift "30% more" than a [[Delta IV Heavy]].<ref>{{Cite web |author= ToryBruno (President & CEO of ULA) |url= https://www.reddit.com/r/ula/comments/7wxhqc/vulcan_heavy/du4wrv4/ |title= Vulcan Heavy? |website= Reddit.com |date= |access-date=2018-04-12}}</ref> By March 2018, ULA had begun to publicly refer to the new Vulcan first stage with the Centaur V second stage as the ''Vulcan Centaur''.<ref name=sn20180325>{{cite news |last=Erwin|first=Sandra |url=https://tools.wmflabs.org/makeref/ |title=Air Force stakes future on privately funded launch vehicles. Will the gamble pay off? |work=[[SpaceNews]] |date=25 March 2018 |accessdate=2018-06-24}}</ref>

In May 2018, ULA selected Aerojet Rocketdyne's RL10 engine for the Vulcan Centaur upper stage.<ref>{{cite web |last1=Tribou |first1=Richard |url=http://www.orlandosentinel.com/news/space/go-for-launch/os-united-launch-alliance-rocket-aerodyne-vulcan-20180511-story.html |title=ULA chooses Aerojet Rocketdyne over Blue Origin for Vulcan's upper stage engine |work=Orlando Sentinel |date= 11 May 2018 |accessdate= 13 May 2018}}</ref>

In late September 2018, ULA announced that the Blue Origin BE-4 engine is to power the first stage of the Vulcan.<ref name=ULA20180927 />

== Funding ==
Vulcan is being funded by a combination of [[government funding|government]] and [[private capital|private]] funds.<ref name=sn20160310/><ref name=sn20180325/> The initial private funding for Vulcan development, during the first 18 months after announcement in October 2014, was approved only for the short term. By April 2015, it became public that the United Launch Alliance board of directors — composed entirely of executives from Boeing and Lockheed Martin — was approving development funding on only a quarter-by-quarter basis.<ref name="dbj20150415">{{cite news |last1=Avery|first1=Greg |title=The fate of United Launch Alliance and its Vulcan rocket may lie with Congress |url= http://www.bizjournals.com/denver/blog/boosters_bits/2015/04/the-fate-of-united-launch-alliance-and-its-vulcan.html?page=all |issue=Denver Business Journal |date=2015-04-16 |accessdate=28 April 2015}}</ref> Funding remained limited to quarterly approvals in June 2015, and Lockheed Martin was actively working to use the funding limitation to get the [[US Congress]] to change existing law and allow extension of ULA ability to acquire [[RD-180]] engines for the Atlas V.<ref>[https://finance.yahoo.com/news/airshow-lockheed-says-rocket-launch-171639395.html "AIRSHOW-Lockheed says rocket launch venture urgently needs U.S. law waiver"]. Yahoo Finance, June 14, 2015.</ref> In March 2016, executives from ULA indicated that the practice of quarter-by-quarter investment for Vulcan development would continue.<ref name=sn20160310>{{cite news |last=Gruss |first=Mike |url=http://spacenews.com/ulas-parent-companies-still-support-vulcan-with-caution/ |title=ULA’s parent companies still support Vulcan … with caution |work=[[SpaceNews]] |date=2016-03-10 |accessdate=2016-03-10}}</ref>

By March 2016, the [[USAF|US Air Force]] had committed up to {{USD|202 million}} of funding for Vulcan development. ULA has not "put a firm price tag on [the total cost of Vulcan development but ULA CEO Tory Bruno has] said new rockets typically cost $2 billion, including $1 billion for the main engine."<ref name=sn20160310/> ULA Board of Directors member, and Boeing executive (President of Boeing's Network and Space Systems (N&SS) division), Craig Cooning said in April 2016 that he is confident that the US Air Force will invest in further funding of Vulcan development costs.<ref name=dd20160412>{{cite news |last=Host|first=Pat |url=http://www.defensedaily.com/cooning-confident-air-force-will-invest-in-vulcan-development/ |title=Cooning Confident Air Force Will Invest In Vulcan Development |work=Defense Daily |date=2016-04-12 |accessdate=2016-04-13}}</ref>

In September 2017 the bill for the proposed [[National Defense Authorization Act]] for [[National Defense Authorization Act for Fiscal Year 2018|Fiscal Year 2018]] carried language in the House version inserted by [[United States House of Representatives|Congressman]] [[Mike Rogers (Alabama politician)|Mike Rogers]]. This language would limit the [[United States Department of Defense|US DoD]], and hence the [[United States Air Force|US Air Force]], from allocating funding to ULA for the Vulcan rocket for the fiscal year 2018.{{update after|2018|5|13}}

In March 2018, ULA CEO Tory Bruno said "Vulcan Centaur [had been] 75 percent privately funded" up to that time.<ref name=sn20180325/> In 2016, the US Congress had authorized the USAF to "sign deals with the space industry to co-finance the development of new rocket propulsion systems. The program known as the [[Launch Service Agreement]] (LSA) fits the Air Force's broader goal to get out of the business of "buying rockets" and instead acquire end-to-end [[launch service provider|services]] from companies. The Air Force signed cost-sharing partnerships with [launch vehicle company] ULA, [launch vehicle and rocket engine manufacturers] SpaceX [and] [[Orbital ATK]], and [with rocket engine supplier] Aerojet Rocketdyne. The original request for proposals noted the Air Force wants to "leverage commercial launch solutions in order to have at least two domestic, commercial launch service providers." In October 2018, ULA was awarded $967 million to develop a prototype Vulcan launch system.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

== Design approach and description ==
[[File:Blue Origin BE-4 rocket engine, sn 103, April 2018 -- LCH4 inlet side view.jpg|thumb|The first hotfire Blue Origin BE-4 rocket engine at the 34th Space Symposium in Colorado Springs, Colorado, April 2018, showing the liquid methane inlet side of the engine.]]

ULA took an incremental approach to the development of their first launch vehicle design<ref name=sn20150413/> utilizing various technologies previously developed by its two parent companies: choosing significant Boeing Delta IV technology as well as Lockheed Martin Atlas technology. In addition, ULA began an engine selection competition in 2015 between engine suppliers Aerojet Rocketdyne and Blue Origin for both the booster and upper stages. It continued the tradition of is parent companies to accept a large amount of development funding from the US government, while adding elements of private capital to fund a portion of development cost.<ref name="sn20150413"/><ref name="sn20150424"/><ref name="wsj20150910"/> The engine competition continued into 2018.

The first stage propellant tanks are derived from those of the Delta IV, using two of the {{convert|550000|lbf|kN|order=flip|adj=on|lk=on}}-thrust [[BE-4]] engines.<ref name="sn20140917" /><ref name="spacenews1">{{cite news |url= http://spacenews.com/ulas-vulcan-rocket-to-be-rolled-out-in-stages/ |publisher= Space News |title= ULA’s Vulcan Rocket To be Rolled out in Stages |date= 13 April 2015 |author= Mike Gruss}}</ref><ref name="aw2015-05-11">{{cite news |first=Amy |last=Butler |url=http://aviationweek.com/space/industry-team-hopes-resurrect-atlas-v-post-rd-180 |title=Industry Team Hopes To Resurrect Atlas V Post RD-180 |work=[[Aviation Week & Space Technology]] |date=11 May 2015 |accessdate=12 May 2015 |archive-url=https://web.archive.org/web/20150512205445/http://aviationweek.com/space/industry-team-hopes-resurrect-atlas-v-post-rd-180 |archive-date=12 May 2015 |deadurl=no}}</ref> At announcement in 2014, the BE-4 engine was already in its third year of development by Blue Origin, and ULA expected the new stage and engine to start flying no earlier than 2019.

Vulcan initially planned to use an upgraded variant of the [[Centaur (rocket stage)|Centaur]] upper stage used on Atlas V, with a plan to later upgrade to ACES.<ref>{{cite news |url= http://spacenews.com/op-ed-building-on-a-successful-record-in-space-to-meet-the-challenges-ahead/ |publisher= Space News |title= Building on a successful record in space to meet the challenges ahead |date= 10 October 2017 |author= Bruno, Tory}}</ref> The design also uses a variable number of optional solid rocket boosters, called the [[Graphite-Epoxy Motor]] (GEM) 63XL, derived from the new solid boosters planned for Atlas V.<ref name=sfi20150923>{{cite news |url= http://www.spaceflightinsider.com/organizations/ula/ula-selects-orbital-atks-gem-6363-xl-srbs-for-atlas-v-and-vulcan-boosters/ |title= ULA selects Orbital ATK’s GEM 63/63 XL SRBs for Atlas V and Vulcan boosters |author= Jason Rhian |date= 23 September 2015 |publisher= Spaceflight Insider}}</ref> With a {{nowrap|4-meter}} diameter payload fairing it can use up to four SRBs, and with a {{nowrap|5-meter}} fairing it can use up to six SRBs. The first stage can optionally have from zero to six [[solid rocket booster]]s (SRBs).<ref name=Apr2015/>

In August 2016 ULA's President and CEO said they intend to [[human-rating certification|human rate]] both the Vulcan and ACES.<ref name="Man_rate">{{cite web |last1=Tory Bruno |title="@A_M_Swallow @ULA_ACES We intend to human rate Vulcan/ACES" |url=https://twitter.com/torybruno/status/770579558726668288 |website=Twitter.com |accessdate=August 30, 2016}}</ref>

From 2015–2018, ULA designed two versions of the Vulcan first stage, one using the BE-4 with a {{convert|5.4|m|ft|sp=us|abbr=on|adj=on}} outer diameter to support the less-dense [[liquid methane|methane]] fuel and an alternative [[AR1 (rocket engine)|AR1]] design with the same {{convert|3.81|m|ft|sp=us|abbr=on|adj=on}} diameter as Atlas V for the denser {{nowrap|[[RP-1]]}} (kerosene) fuel.<ref name=sn20160316/>

==Engine choice==
A competition among engine vendors, [[Blue Origin]] and [[Aerojet Rocketdyne]] has been underway since approximately 2014, with final engine selection originally slated for 2017<ref name=sn20170405/> but subsequently moved to 2018.

In April 2017, just as a major series of ground tests of the Blue Origin [[BE-4]] were set to occur over the summer, ULA indicated that Blue continued to lead, but the final selection would not be made until after the test series is complete, particularly a variety of tests aimed at characterizing any [[combustion instability]] in the design.<ref name=sn20170405>[http://spacenews.com/bruno-vulcan-engine-downselect-is-blues-to-lose/ "Bruno: Vulcan engine downselect is Blue's to lose"]. Space News, April 5, 2017</ref> Blue Origin experienced a test anomaly on 13 May 2017 reporting that they lost a set of BE-4 [[Powerpack (rocket engine)|powerpack]] hardware.<ref>[http://spacenews.com/blue-origin-suffers-be-4-testing-mishap/ "Blue Origin suffers BE-4 testing mishap"]. Space News, May 15, 2017.</ref>

The BE-4 was first test-fired, at 50 percent thrust for three seconds, in October 2017.<ref name=ars20171019>{{cite news |last1=Berger |first1=Eric |title=Blue Origin just sent a jolt through the aerospace industry |url=https://arstechnica.com/science/2017/10/blue-origin-has-successfully-tested-its-powerful-be-4-rocket-engine/ |publisher=Ars Technica |date=19 October 2017 |accessdate=19 October 2017}}</ref> As of February 2018, Aerojet Rocketdyne is asking for additional funds from USAF to complete work on the AR-1 engine.<ref>{{cite news |last1=Foust |first1=Jeff |title=Air Force and Aerojet Rocketdyne renegotiating AR1 agreement |url=http://spacenews.com/air-force-and-aerojet-rocketdyne-renegotiating-ar1-agreement/ |publisher=Space News |date=16 February 2018}}</ref>

In late September 2018, ULA selected the BE-4 to power the Vulcan first stage. <ref>{{cite web|title=United Launch Alliance Building Rocket of the Future with Industry-Leading Strategic Partnerships|url=https://www.ulalaunch.com/about/news-detail/2018/09/27/united-launch-alliance-building-rocket-of-the-future-with-industry-leading-strategic-partnerships|date=28 Sep 2018}}</ref>

== References ==
{{Reflist|30em}}

== External links ==
* {{Official website|www.ulalaunch.com/Products_Vulcan.aspx}}
* [https://www.youtube.com/watch?v=xTTkrxVR_20 ISPCS 2015 Keynote], Mark Peller, Program Manager of Major Development at ULA and Vulcan Program Manager discusses Vulcan, 8 October 2015. Key discussion of Vulcan is at 12:20 point in video.

{{Expendable launch systems}}
{{US launch systems}}
{{Reusable launch systems}}

[[Category:Space launch vehicles of the United States]]
[[Category:United Launch Alliance]]

Vulcan Centaur

2018-10-11T23:20:08Z

Blastr42:

{{hatnote|This article is about the proposed American Vulcan launch vehicle. Not to be confused with the Russian [[Vulkan-Hercules]] concept launch vehicle or the European [[Vulcain]] rocket engine. For other uses, see [[Vulcan (disambiguation)|Vulcan]].}}
{{Infobox rocket
|name = Vulcan
|image = ULA_Vulcan20180927.jpg
|caption = A simulated expanded view of the 561-configuration Vulcan Centaur rocket.
|function = Partly-reusable [[launch vehicle]]
|manufacturer = [[United Launch Alliance]]
|country-origin = United States
|height = {{convert|58.3|m|ft|abbr=on}}
|diameter = {{convert|5.4|m|ft|abbr=on}}<ref>{{cite web|last1=Peller|first1=Mark|title=United Launch Alliance|url=http://www.ispcs.com/content/files/Mark%20Peller.pdf|accessdate=2016-03-30|archive-url=https://web.archive.org/web/20160412062627/http://www.ispcs.com/content/files/Mark%20Peller.pdf|archive-date=2016-04-12|dead-url=yes|df=}}</ref>
|mass ={{convert|546,700|kg|lbs|abbr=on}}
|stages = 2

|capacities =
{{Infobox rocket/payload
|location = [[Low Earth Orbit|LEO]]
|kilos = {{cvt|56000|lb|order=flip}}<ref name=ULA20180927>{{cite web |title=United Launch Alliance Building Rocket of the Future with Industry-Leading Strategic Partnerships ULA Selects Blue Origin Advanced Booster Engine for Vulcan Centaur Rocket System |url=https://www.ulalaunch.com/about/news/2018/09/27/united-launch-alliance-building-rocket-of-the-future-with-industry-leading-strategic-partnerships |publisher=United Launch Alliance |date=27 September 2018}}</ref>(Vulcan Heavy [[Centaur V|Centaur]])}}

{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = {{cvt|33000|lb|order=flip}}<ref name=ULA20180927 />(Vulcan Heavy [[Centaur V|Centaur]])}}

{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = {{cvt|16000|lb|order=flip}}<ref name=ULA20180927 />(Vulcan Heavy [[Centaur V|Centaur]])}}
|comparable = {{flatlist|
* [[Ariane 5]]
* [[Atlas V]]
* [[Delta IV Heavy]]
* [[Falcon Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Omega_(rocket)|OmegA]]
* [[Saturn C-3]]
}}
|status = In development
|sites = [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 41|SLC-41]] [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 3|SLC-3E]]<ref name="sn20151012">{{cite news |last1=Clark|first1=Stephen |title=ULA selects launch pads for new Vulcan rocket |url=http://spaceflightnow.com/2015/10/12/ula-selects-launch-pads-for-new-vulcan-rocket/ |accessdate=12 October 2015 |work=Spaceflight Now |date=12 October 2015}}</ref>
|launches =
|success =
|fail =
|partial =
|first= Mid-2020 (planned)<ref name=ULA20180927 />
|last=
|stagedata = 
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name =
|number = 0–6
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = GEM 63XL<ref>{{cite web|last1=Rhian|first1=Jason|title=ULA selects Orbital ATK's GEM 63/63XL SRBs for Atlas V and Vulcan Boosters|url=http://www.spaceflightinsider.com/organizations/ula/ula-selects-orbital-atks-gem-6363-xl-srbs-for-atlas-v-and-vulcan-boosters/|website=Spaceflight Insider|accessdate=2015-09-25}}</ref>
|solid = yes
|thrust = {{convert|2201.7|kN|abbr=on}}
|total = 
|SI = 
|burntime = 
|fuel = [[HTPB]]
}}
{{Infobox rocket/stage
|type = stage
|diff = 
|stageno = First
|name = 
|number = 
|length = 
|diameter = {{convert|5.4|m|abbr=on}}
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 2× [[BE-4]]
|solid = 
|thrust = {{convert|1100000|lb-f|kN|order=flip|lk=in|abbr=on}}
|total = 
|SI = 
|burntime = 
|fuel = [[Liquid methane|CH4]] / [[Liquid oxygen|LOX]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name = [[Centaur (rocket stage)|Centaur]] (initial flights, late-2010s)
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 2× [[RL10]]-C<ref>{{cite tweet |user=ulalaunch |number=1045406241131032576 |date=27 September 2018 |title=Our partnerships w/ @BlueOrigin as well as @AerojetRDyne @NorthropGrumman L-3 Avionics & @RUAGSpace will allow this next-gen American rocket to affordably transform the future of space launch! }}</ref><ref>{{Cite web|url=https://www.ulalaunch.com/rockets/vulcan-centaur|title=Vulcan Centaur|website=United Launch Alliance|language=en|access-date=2018-10-02}}</ref><ref>{{cite web|title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine for Next-generation Vulcan Centaur Upper Stage|url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage|website=United Launch Alliance website|accessdate=11 May 2018}}</ref>
|solid = 
|thrust = {{convert|207.6|kN|lb-f|lk=in|abbr=on}}{{citation needed|date=February 2018}}
|total = 
|SI = {{convert|448.5|isp}}
|burntime = 
|fuel = [[Liquid hydrogen|LH2]] / [[Liquid oxygen|LOX]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name = [[Advanced Cryogenic Evolved Stage|ACES]] (proposed, mid-2020s)
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 4× [[RL10]]-C or 1× [[BE-3]] engine (TBC)
|solid = 
|thrust = 
|total = 
|SI = 
|burntime = 
|fuel = [[Liquid hydrogen|LH2]] / [[Liquid oxygen|LOx]]
}}
}}

The '''''Vulcan''''' rocket, also known as the '''''Vulcan Centaur''''',<ref name=sn20180325/> is an American heavy-payload [[launch vehicle]] under [[new product development|development]] since 2014 by [[United Launch Alliance]] (ULA), funded by a [[public–private partnership]] with the [[Federal government of the United States|U.S. government]]. ULA expects the [[maiden flight|first launch]] of the new rocket to occur no earlier than mid-2020.<ref name=SpaceNewsFoust201801>{{cite tweet |user=jeff_foust |number=954054070821670912 |title=Tom Tshudy, ULA: with Vulcan we plan to maintain reliability and on-time performance of our existing rockets, but at a very affordable price. First launch mid-2020. |date=18 January 2018}}</ref>

Through the first several years of the development project, the ULA board of directors had made only short-term (quarterly) funding commitments to the rocket program, and it remains unclear if long-term private funding will be available to finish the project. {{As of|2018|10}}, the US government had committed approximately {{USD|1.2 billion}} to Vulcan development.<ref name=sn20160310/><ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

== History ==
United Launch Alliance had considered several launch vehicle concepts in the decade since the company was formed in 2006. Various concepts for derivative vehicles based on the [[Atlas (rocket)|Atlas]] and [[Delta (rocket)|Delta]] lines of launch vehicles they inherited from their predecessor companies were presented to the U.S. government for funding. None were funded beyond concept stage.

In early 2014, geopolitical and [[Federal government of the United States|U.S.]] political considerations involving [[international sanctions during the Ukrainian crisis]], led to an effort by ULA to consider possibly replacing the Russian-supplied [[RD-180]] engine used on the first stage booster of the [[Atlas V]]. Formal study contracts were issued by ULA in June 2014 to several U.S. rocket engine suppliers.<ref name="sn20140917" /> ULA was also facing competition from [[SpaceX]], then seen to affect ULA's core national security market of U.S. military launches, and by July 2014 the [[United States Congress]] was debating whether to legislate a ban on future use of the RD-180.<ref name="sn20150424">{{cite news |last1=Gruss|first1=Mike |title=Evolution of a Plan : ULA Execs Spell Out Logic Behind Vulcan Design Choices |url=http://spacenews.com/evolution-of-a-plan-ula-execs-spell-out-logic-behind-vulcan-design-choices/ |work=Space News |date=2015-04-24 |accessdate=25 April 2015}}</ref>

=== New first stage booster ===
In September 2014, ULA announced that it had entered into a partnership with [[Blue Origin]] to develop the [[BE-4]] [[liquid oxygen]] (LOX) and [[liquid methane]] (CH4) engine to replace the RD-180 on a new first stage [[Booster (rocketry)|booster]]. The Blue engine was already in its third year of development by Blue Origin, and ULA said it expected the new stage and engine to start flying no earlier than 2019.<ref name="dd20150207" /> Two of the {{convert|550000|lbf|kN|order=flip|adj=on|lk=on}}-thrust BE-4 engines were to be used on a new launch vehicle booster.<ref name="sn20140917">{{cite news |last1=Ferster|first1=Warren |title=ULA To Invest in Blue Origin Engine as RD-180 Replacement |url=http://www.spacenews.com/article/launch-report/41901ula-to-invest-in-blue-origin-engine-as-rd-180-replacement |date=2014-09-17 |work=Space News |access-date=2014-09-19}}</ref> ULA referred to the successor concept vehicle as a "next generation launch system"<ref name="dbj20141016" /> and used that descriptor into early 2015.<ref name="dd20150207">{{cite news |last1=Fleischauer|first1=Eric |title=ULA's CEO talks challenges, engine plant plans for Decatur |url=http://www.decaturdaily.com/news/ula-s-ceo-talks-challenges-engine-plant-plans-for-decatur/article_8ba49046-af4a-11e4-97ef-ff58591d43fc.html |work=Decatur Daily |date=7 February 2015 |accessdate=2015-04-17}}</ref>

In October 2014, ULA announced a major restructuring of company processes and workforce to reduce launch costs by half. One of the reasons given for the restructuring and new cost reduction goals was [[Space launch market competition|new competition in the launch market]] from SpaceX.<ref name="dbj20141016" /><ref name="sn20150424" /> ULA planned to have preliminary design ideas in place for a blending of its existing Atlas V and [[Delta IV]] technologies by the end of 2014, to build a successor to the Atlas V that would allow the company to halve Atlas V launch costs.<ref name="dbj20141016">{{cite news |last1=Avery|first1=Greg |title=ULA plans new rocket, restructuring to cut launch costs in half |url=http://www.bizjournals.com/denver/blog/boosters_bits/2014/10/exclusive-ula-plans-a-new-rocket-restructuring-to.html |accessdate=2015-04-17 |work=Denver Business Journal |date=2014-10-16}}</ref> A part of the restructuring effort was described as the effort to co-develop the alternative BE-4 engine with Blue Origin for the new launch vehicle.<ref name="spo20141114">{{cite news |last1=Delgado|first1=Laura M. |title=ULA's Tory Bruno Vows To Transform Company |url=http://www.spacepolicyonline.com/news/ulas-tory-bruno-vows-to-transform-company |accessdate=2015-04-17 |work=SpacePolicyOnline.com |date=2014-11-14}}</ref>

=== Unveiling ===
On 13 April 2015, CEO [[Tory Bruno]] unveiled the new ULA launch vehicle as the ''Vulcan'' at the 31st [[Space Symposium]], a new [[two-stage-to-orbit]] (TSTO) rocket that would be rolled out incrementally. The Vulcan name was chosen after an online poll to select the name. [[Vulcan Inc.]] stated that it held the trademark on the name and contacted ULA.<ref name="nbc20150413">{{cite news |last1=Boyle |first1=Alan |url=http://www.nbcnews.com/science/space/united-launch-alliance-boldly-names-its-next-big-rocket-vulcan-n340881 |work=NBC |title=United Launch Alliance Boldly Names Its Next Rocket: Vulcan! |date=2015-04-13 |accessdate=2015-04-17}}</ref>{{update after|2018|5|13}} ULA stated its goal was to sell a "barebones Vulcan" for half the [[price]] of a basic Atlas V rocket, which sold for about $164 million {{asof|2015|lc=y}}. Addition of strap-on boosters for heavier satellites would increase the price.<ref name="sfn-20150422">{{cite news |url=http://spaceflightnow.com/2015/04/22/ula-needs-commercial-business-to-close-vulcan-rocket-business-case/ |title=ULA needs commercial business to close Vulcan rocket business case |first1=Stephen |last1=Clark |work=Spaceflight Now |date=22 April 2015 |accessdate=23 April 2015}}</ref> At the announcement, the ULA [[Board of directors|board]] had not yet approved the new launch vehicle, with first launch planned in 2019.<ref name="sn20150424" />

ULA put forth an "incremental approach" to rolling out the vehicle and its technologies,<ref name="sn20150413">{{cite news |last1=Gruss |first1=Mike |url=http://spacenews.com/ulas-vulcan-rocket-to-be-rolled-out-in-stages/ |work=SpaceNews |title=ULA’s Vulcan Rocket To be Rolled out in Stages |date=2015-04-13 |accessdate=2015-04-17}}</ref> with Vulcan deployment beginning with the first stage, based on the Delta IV's fuselage diameter and production process, expected to use two BE-4 engines. The [[Aerojet Rocketdyne#AR1|Aerojet Rocketdyne AR1 engine]] was retained by ULA as a contingency option. In late September 2018, ULA announced that the BE-4 engine was to power the first stage.<ref name=":0">{{Cite news|url=https://www.defensenews.com/newsletters/military-space-report/2018/09/27/ula-selects-blue-origin-engine-to-power-launch-vehicle/|title=ULA selects Blue Origin engine to power launch vehicle|last=Mehta|first=Aaron|date=2018-09-27|work=Defense News|access-date=2018-09-27|language=en-US}}</ref> The first stage will be able to optionally use from one to six [[solid rocket booster]]s (SRBs) for added liftoff thrust,<ref name=Apr2015>[http://www.ulalaunch.com/ula-unveils-americas-new-rocket-vulcan.aspx?title=United+Launch+Alliance+Unveils+America%E2%80%99s+New+Rocket+%E2%80%93+Vulcan%3a+Innovative+Next+Generation+Launch+System+will+Provide+Country%E2%80%99s+Most+Reliable%2c+Affordable+and+Accessible+Launch+Service United Launch Alliance Unveils America’s New Rocket – Vulcan: Innovative Next Generation Launch System will Provide Country’s Most Reliable, Affordable and Accessible Launch Service. April 2015]</ref> launch a heavier payload than the highest-rated Atlas V in the six-SRB configuration.

ULA announced a feature they could subsequently develop which would make the first stage partly reusable: allowing the engines to detach from the vehicle after [[main engine cutoff]], descend through the [[atmospheric reentry|atmosphere]] with a heat shield and parachute, being captured by a helicopter in mid-air.<ref name="nbc20150413" /> ULA estimated that reusing the engines in this way would reduce the cost of the first stage propulsion by 90%, where propulsion is 65% of the total first stage cost.<ref name="sfn20150414">{{cite news |last1=Ray|first1=Justin |url=http://spaceflightnow.com/2015/04/14/ula-chief-explains-reusability-and-innovation-of-new-rocket/ |title=ULA chief explains reusability and innovation of new rocket |work=Spaceflight Now |date=14 April 2015 |accessdate=2015-04-17}}</ref> Initial configurations of Vulcan were intended then to use the same [[Centaur (rocket stage)|Centaur upper stage]] as the Atlas V, with its existing [[RL10]] engines, while a later advanced cryogenic upper stage — called the ''[[Advanced Cryogenic Evolved Stage]]'' (ACES) — was conceptually planned for full development by ULA in the late 2010s. ACES would be LOX and [[liquid hydrogen]] (LH2) powered by one to four rocket engines yet to be selected, and would include the [[Integrated Vehicle Fluids]] technology that could allow much longer on-orbit life of the upper stage, measured in weeks rather than hours.<ref name="dp20150413">{{cite web |url=http://www.denverpost.com/business/ci_27905093/america-meet-vulcan-your-next-united-launch-alliance |title=America, meet Vulcan, your next United Launch Alliance rocket |work=Denver Post |date=2015-04-13 |accessdate=2015-04-17}}</ref><ref name="sn20150413" />

{{Anchor|Vulcan Heavy}}In May 2015, ULA released a chart showing a potential future Vulcan Heavy three-core launch vehicle concept with {{cvt|50000|lb|order=flip|adj=on}}-payload capacity to [[geostationary transfer orbit]], while a single-core Vulcan 561 with the ACES upper stage would have {{cvt|33200|lb|order=flip|adj=on}} capacity to the same orbit.<ref name="ula20150505">{{cite tweet |author=Tory Bruno |author-link=Tory Bruno |user=torybruno |number=595628488410963970 |title=ULA Full Spectrum Lift Capability |date=5 May 2015 |access-date=8 May 2015}}</ref>

In September 2015, ULA and Blue Origin announced an agreement to expand production capabilities to include the [[BE-4]] rocket engine then in development and test. However, ULA also reconfirmed that the decision on the BE-4 versus the AJR AR1 would not be made until late 2016, with maiden flight of Vulcan no earlier than 2019.<ref name="wsj20150910">{{cite news |url=https://www.wsj.com/articles/boeing-lockheed-differ-on-whether-to-sell-rocket-joint-venture-1441933638 |title=Boeing, Lockheed Differ on Whether to Sell Rocket Joint Venture |work=Wall Street Journal |date=10 September 2015 |accessdate=2015-09-12}}</ref>

=== Engine testing and design optimization ===
{{As of|2016|01}}, full-engine testing of the BE-4 was planned to begin prior to the end of 2016,<ref name="sn20160123b">{{cite news |last=Berger|first=Brian |url=http://spacenews.com/launch-land-repeat-blue-origin-posts-video-of-new-shepards-friday-flight/ |title=Launch. Land. Repeat: Blue Origin posts video of New Shepard’s Friday flight |work=SpaceNews |date=2016-01-23 |accessdate=2016-01-24 |quote=''Also this year, we’ll start full-engine testing of the BE-4''}}</ref>{{update after|2017}} while ULA was designing two versions of the Vulcan first stage, one using the BE-4 with a {{convert|5.4|m|ft|sp=us|abbr=on|adj=on}} outer diameter to support the less-dense [[liquid methane|methane]] fuel and an AR1 design with the same {{convert|3.81|m|ft|sp=us|abbr=on|adj=on}} diameter as Atlas V for the denser [[RP-1]] (kerosene) fuel.<ref name=sn20160316>{{cite news |last=de Selding|first=Peter B. |url=http://spacenews.com/ula-intends-to-lower-its-costs-and-raise-its-cool-to-compete-with-spacex/ |title=ULA intends to lower its costs, and raise its cool, to compete with SpaceX |work=[[SpaceNews]] |date=2016-03-16 |accessdate=2016-03-19 |quote=Methane rocket has a lower density so we have a 5.4 meter design outside diameter, while drop back to the Atlas V size for the kerosene AR1 version. ... Aerojet Rocketdyne AR1 ... haven't built any hardware yet ... additive manufacturing is revolutionizing complex casting ... Aerojet is investing a little bit of their own money. Primarily they are counting on the government's RPS (Rocket Propulsion System) contracts to drive the funding.}}</ref>

ULA completed the [[Preliminary Design Review]] (PDR) in March 2016 for one of the two parallel designs: the Vulcan/Centaur launch vehicle with dual Blue Origin BE-4 engines. The PDR "confirms that the design meets the requirements for the diverse set of missions it will support."<ref name=ula20160324>{{cite web |url=http://www.ulalaunch.com/ula-completes-Vulcan-Centaur-PDR.aspx |title=United Launch Alliance Completes Preliminary Design Review for Next-Generation Vulcan Centaur Rocket |deadurl=no |archiveurl= https://web.archive.org/web/20160325145546/http://www.ulalaunch.com/ula-completes-Vulcan-Centaur-PDR.aspx |archivedate=2016-03-25 |accessdate=2016-03-25}}</ref> In the event, BE-4 engine testing did not begin until 2017.<ref name=ars20171019/>

In April 2016, ULA CEO Tory Bruno stated that the company was targeting a complete launch services price of $99 million for base Vulcan with no solid rocket boosters.<ref name=reuters20160414>{{Cite news |url=https://www.reuters.com/article/us-space-ula-layoffs-idUSKCN0XB2HQ |title=United Launch Alliance to lay off up to 875 by end of 2017: CEO |date=2016-04-14 |newspaper=Reuters |access-date=2016-05-07}}</ref> Also the ULA team was to be reduced by about one quarter of its legacy workforce, or more than 800 employees, by end 2017 in order to better [[Space launch market competition|compete]] with SpaceX and Blue Origin offerings in the US launch market.<ref name=reuters20160414/>{{update after|2017}} In October 2017, ULA announced that [[Bigelow Aerospace]]'s [[B330]] would be flown on a Vulcan 562 configuration rocket rather than the previously planned [[Atlas V]].<ref name="ula20171017">{{cite press release |url=http://www.ulalaunch.com/bigelow-aerospace-and-ula-lunar-depot.aspx |title=Bigelow Aerospace and United Launch Alliance Announce Agreement to Place a B330 Habitat in Low Lunar Orbit |publisher=United Launch Alliance |date=October 17, 2017 |accessdate=January 18, 2018}}</ref>

A delay was announced in January 2018 pushing first launch back from 2019 to mid-2020.<ref name=SpaceNewsFoust201801/> Also announced was an upgrade to the Centaur second stage to include up to four RL10 engines, to be called [[Centaur V]].<ref>{{cite web |title=Vulcan Centaur |url=https://www.ulalaunch.com/rockets/vulcan-centaur |publisher=ULA |accessdate=16 February 2018}}</ref>{{better source|date=May 2018}} While a tri-core Vulcan Heavy with a payload of {{cvt|50000|lb|order=flip}} had been conceptualized in 2015,<ref name="ula20150505" /> ULA clarified that it would not build a multi-core configuration as the upgrades to the Centaur second stage would allow a single core Vulcan Centaur to lift "30% more" than a [[Delta IV Heavy]].<ref>{{Cite web |author= ToryBruno (President & CEO of ULA) |url= https://www.reddit.com/r/ula/comments/7wxhqc/vulcan_heavy/du4wrv4/ |title= Vulcan Heavy? |website= Reddit.com |date= |access-date=2018-04-12}}</ref> By March 2018, ULA had begun to publicly refer to the new Vulcan first stage with the Centaur V second stage as the ''Vulcan Centaur''.<ref name=sn20180325>{{cite news |last=Erwin|first=Sandra |url=https://tools.wmflabs.org/makeref/ |title=Air Force stakes future on privately funded launch vehicles. Will the gamble pay off? |work=[[SpaceNews]] |date=25 March 2018 |accessdate=2018-06-24}}</ref>

In May 2018, ULA selected Aerojet Rocketdyne's RL10 engine for the Vulcan Centaur upper stage.<ref>{{cite web |last1=Tribou |first1=Richard |url=http://www.orlandosentinel.com/news/space/go-for-launch/os-united-launch-alliance-rocket-aerodyne-vulcan-20180511-story.html |title=ULA chooses Aerojet Rocketdyne over Blue Origin for Vulcan's upper stage engine |work=Orlando Sentinel |date= 11 May 2018 |accessdate= 13 May 2018}}</ref>

In late September 2018, ULA announced that the Blue Origin BE-4 engine is to power the first stage of the Vulcan.<ref name=ULA20180927 />

== Funding ==
Vulcan is being funded by a combination of [[government funding|government]] and [[private capital|private]] funds.<ref name=sn20160310/><ref name=sn20180325/> The initial private funding for Vulcan development, during the first 18 months after announcement in October 2014, was approved only for the short term. By April 2015, it became public that the United Launch Alliance board of directors — composed entirely of executives from Boeing and Lockheed Martin — was approving development funding on only a quarter-by-quarter basis.<ref name="dbj20150415">{{cite news |last1=Avery|first1=Greg |title=The fate of United Launch Alliance and its Vulcan rocket may lie with Congress |url= http://www.bizjournals.com/denver/blog/boosters_bits/2015/04/the-fate-of-united-launch-alliance-and-its-vulcan.html?page=all |issue=Denver Business Journal |date=2015-04-16 |accessdate=28 April 2015}}</ref> Funding remained limited to quarterly approvals in June 2015, and Lockheed Martin was actively working to use the funding limitation to get the [[US Congress]] to change existing law and allow extension of ULA ability to acquire [[RD-180]] engines for the Atlas V.<ref>[https://finance.yahoo.com/news/airshow-lockheed-says-rocket-launch-171639395.html "AIRSHOW-Lockheed says rocket launch venture urgently needs U.S. law waiver"]. Yahoo Finance, June 14, 2015.</ref> In March 2016, executives from ULA indicated that the practice of quarter-by-quarter investment for Vulcan development would continue.<ref name=sn20160310>{{cite news |last=Gruss |first=Mike |url=http://spacenews.com/ulas-parent-companies-still-support-vulcan-with-caution/ |title=ULA’s parent companies still support Vulcan … with caution |work=[[SpaceNews]] |date=2016-03-10 |accessdate=2016-03-10}}</ref>

By March 2016, the [[USAF|US Air Force]] had committed up to {{USD|202 million}} of funding for Vulcan development. ULA has not "put a firm price tag on [the total cost of Vulcan development but ULA CEO Tory Bruno has] said new rockets typically cost $2 billion, including $1 billion for the main engine."<ref name=sn20160310/> ULA Board of Directors member, and Boeing executive (President of Boeing's Network and Space Systems (N&SS) division), Craig Cooning said in April 2016 that he is confident that the US Air Force will invest in further funding of Vulcan development costs.<ref name=dd20160412>{{cite news |last=Host|first=Pat |url=http://www.defensedaily.com/cooning-confident-air-force-will-invest-in-vulcan-development/ |title=Cooning Confident Air Force Will Invest In Vulcan Development |work=Defense Daily |date=2016-04-12 |accessdate=2016-04-13}}</ref>

In September 2017 the bill for the proposed [[National Defense Authorization Act]] for [[National Defense Authorization Act for Fiscal Year 2018|Fiscal Year 2018]] carried language in the House version inserted by [[United States House of Representatives|Congressman]] [[Mike Rogers (Alabama politician)|Mike Rogers]]. This language would limit the [[United States Department of Defense|US DoD]], and hence the [[United States Air Force|US Air Force]], from allocating funding to ULA for the Vulcan rocket for the fiscal year 2018.{{update after|2018|5|13}}

In March 2018, ULA CEO Tory Bruno said "Vulcan Centaur [had been] 75 percent privately funded" up to that time.<ref name=sn20180325/> In 2016, the US Congress had authorized the USAF to "sign deals with the space industry to co-finance the development of new rocket propulsion systems. The program known as the [[Launch Service Agreement]] (LSA) fits the Air Force's broader goal to get out of the business of "buying rockets" and instead acquire end-to-end [[launch service provider|services]] from companies. The Air Force signed cost-sharing partnerships with [launch vehicle company] ULA, [launch vehicle and rocket engine manufacturers] SpaceX [and] [[Orbital ATK]], and [with rocket engine supplier] Aerojet Rocketdyne. The original request for proposals noted the Air Force wants to "leverage commercial launch solutions in order to have at least two domestic, commercial launch service providers." In October 2018, ULA was awarded $967 million to develop a prototype Vulcan launch system.<ref>{{Cite news|url=https://spacenews.com/air-force-awards-launch-vehicle-development-contracts-to-blue-origin-northrop-grumman-ula/|title=Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA - SpaceNews.com|last=Erwin|first=Sandra|date=2018-10-10|work=SpaceNews.com|access-date=2018-10-11|language=en-US}}</ref>

== Design approach and description ==
[[File:Blue Origin BE-4 rocket engine, sn 103, April 2018 -- LCH4 inlet side view.jpg|thumb|The first hotfire Blue Origin BE-4 rocket engine at the 34th Space Symposium in Colorado Springs, Colorado, April 2018, showing the liquid methane inlet side of the engine.]]

ULA took an incremental approach to the development of their first launch vehicle design<ref name=sn20150413/> utilizing various technologies previously developed by its two parent companies: choosing significant Boeing Delta IV technology as well as Lockheed Martin Atlas technology. In addition, ULA began an engine selection competition in 2015 between engine suppliers Aerojet Rocketdyne and Blue Origin for both the booster and upper stages. It continued the tradition of is parent companies to accept a large amount of development funding from the US government, while adding elements of private capital to fund a portion of development cost.<ref name="sn20150413"/><ref name="sn20150424"/><ref name="wsj20150910"/> The engine competition continued into 2018.

The first stage propellant tanks are derived from those of the Delta IV, using two of the {{convert|550000|lbf|kN|order=flip|adj=on|lk=on}}-thrust [[BE-4]] engines.<ref name="sn20140917" /><ref name="spacenews1">{{cite news |url= http://spacenews.com/ulas-vulcan-rocket-to-be-rolled-out-in-stages/ |publisher= Space News |title= ULA’s Vulcan Rocket To be Rolled out in Stages |date= 13 April 2015 |author= Mike Gruss}}</ref><ref name="aw2015-05-11">{{cite news |first=Amy |last=Butler |url=http://aviationweek.com/space/industry-team-hopes-resurrect-atlas-v-post-rd-180 |title=Industry Team Hopes To Resurrect Atlas V Post RD-180 |work=[[Aviation Week & Space Technology]] |date=11 May 2015 |accessdate=12 May 2015 |archive-url=https://web.archive.org/web/20150512205445/http://aviationweek.com/space/industry-team-hopes-resurrect-atlas-v-post-rd-180 |archive-date=12 May 2015 |deadurl=no}}</ref> At announcement in 2014, the BE-4 engine was already in its third year of development by Blue Origin, and ULA expected the new stage and engine to start flying no earlier than 2019.

Vulcan initially planned to use an upgraded variant of the [[Centaur (rocket stage)|Centaur]] upper stage used on Atlas V, with a plan to later upgrade to ACES.<ref>{{cite news |url= http://spacenews.com/op-ed-building-on-a-successful-record-in-space-to-meet-the-challenges-ahead/ |publisher= Space News |title= Building on a successful record in space to meet the challenges ahead |date= 10 October 2017 |author= Bruno, Tory}}</ref> The design also uses a variable number of optional solid rocket boosters, called the [[Graphite-Epoxy Motor]] (GEM) 63XL, derived from the new solid boosters planned for Atlas V.<ref name=sfi20150923>{{cite news |url= http://www.spaceflightinsider.com/organizations/ula/ula-selects-orbital-atks-gem-6363-xl-srbs-for-atlas-v-and-vulcan-boosters/ |title= ULA selects Orbital ATK’s GEM 63/63 XL SRBs for Atlas V and Vulcan boosters |author= Jason Rhian |date= 23 September 2015 |publisher= Spaceflight Insider}}</ref> With a {{nowrap|4-meter}} diameter payload fairing it can use up to four SRBs, and with a {{nowrap|5-meter}} fairing it can use up to six SRBs. The first stage can optionally have from zero to six [[solid rocket booster]]s (SRBs).<ref name=Apr2015/>

In August 2016 ULA's President and CEO said they intend to [[human-rating certification|human rate]] both the Vulcan and ACES.<ref name="Man_rate">{{cite web |last1=Tory Bruno |title="@A_M_Swallow @ULA_ACES We intend to human rate Vulcan/ACES" |url=https://twitter.com/torybruno/status/770579558726668288 |website=Twitter.com |accessdate=August 30, 2016}}</ref>

From 2015–2018, ULA designed two versions of the Vulcan first stage, one using the BE-4 with a {{convert|5.4|m|ft|sp=us|abbr=on|adj=on}} outer diameter to support the less-dense [[liquid methane|methane]] fuel and an alternative [[AR1 (rocket engine)|AR1]] design with the same {{convert|3.81|m|ft|sp=us|abbr=on|adj=on}} diameter as Atlas V for the denser {{nowrap|[[RP-1]]}} (kerosene) fuel.<ref name=sn20160316/>

==Engine choice==
A competition among engine vendors, [[Blue Origin]] and [[Aerojet Rocketdyne]] has been underway since approximately 2014, with final engine selection originally slated for 2017<ref name=sn20170405/> but subsequently moved to 2018.

In April 2017, just as a major series of ground tests of the Blue Origin [[BE-4]] were set to occur over the summer, ULA indicated that Blue continued to lead, but the final selection would not be made until after the test series is complete, particularly a variety of tests aimed at characterizing any [[combustion instability]] in the design.<ref name=sn20170405>[http://spacenews.com/bruno-vulcan-engine-downselect-is-blues-to-lose/ "Bruno: Vulcan engine downselect is Blue's to lose"]. Space News, April 5, 2017</ref> Blue Origin experienced a test anomaly on 13 May 2017 reporting that they lost a set of BE-4 [[Powerpack (rocket engine)|powerpack]] hardware.<ref>[http://spacenews.com/blue-origin-suffers-be-4-testing-mishap/ "Blue Origin suffers BE-4 testing mishap"]. Space News, May 15, 2017.</ref>

The BE-4 was first test-fired, at 50 percent thrust for three seconds, in October 2017.<ref name=ars20171019>{{cite news |last1=Berger |first1=Eric |title=Blue Origin just sent a jolt through the aerospace industry |url=https://arstechnica.com/science/2017/10/blue-origin-has-successfully-tested-its-powerful-be-4-rocket-engine/ |publisher=Ars Technica |date=19 October 2017 |accessdate=19 October 2017}}</ref> As of February 2018, Aerojet Rocketdyne is asking for additional funds from USAF to complete work on the AR-1 engine.<ref>{{cite news |last1=Foust |first1=Jeff |title=Air Force and Aerojet Rocketdyne renegotiating AR1 agreement |url=http://spacenews.com/air-force-and-aerojet-rocketdyne-renegotiating-ar1-agreement/ |publisher=Space News |date=16 February 2018}}</ref>

In late September 2018, ULA selected the BE-4 to power the Vulcan first stage. <ref>{{cite web|title=United Launch Alliance Building Rocket of the Future with Industry-Leading Strategic Partnerships|url=https://www.ulalaunch.com/about/news-detail/2018/09/27/united-launch-alliance-building-rocket-of-the-future-with-industry-leading-strategic-partnerships|date=28 Sep 2018}}</ref>

== References ==
{{Reflist|30em}}

== External links ==
* {{Official website|www.ulalaunch.com/Products_Vulcan.aspx}}
* [https://www.youtube.com/watch?v=xTTkrxVR_20 ISPCS 2015 Keynote], Mark Peller, Program Manager of Major Development at ULA and Vulcan Program Manager discusses Vulcan, 8 October 2015. Key discussion of Vulcan is at 12:20 point in video.

{{Expendable launch systems}}
{{US launch systems}}
{{Reusable launch systems}}

[[Category:Space launch vehicles of the United States]]
[[Category:United Launch Alliance]]

Space Shuttle Solid Rocket Booster

2018-09-18T15:49:45Z

Blastr42: /* Displays */

{{refimprove|date=February 2012}}
{{Infobox rocket stage
|name = Solid Rocket Booster
|image = Two Space Shuttle SRBs on the Crawler transporter.jpg
|caption =
|manufacturer = [[Thiokol]], later [[Alliant Techsystems|ATK]] United Space Boosters International, [[Pratt and Whitney]]
|country = United States
|rockets = [[Space Shuttle]]
|height = {{convert|149.16|ft|m|sp=us|abbr=on|order=flip}}
|alt-height =
|diameter = {{convert|12.17|ft|m|sp=us|abbr=on|order=flip}}
|alt-diameter =
|mass = {{convert|1300000|lb|kg|abbr=on|order=flip}}
|alt-mass =
|engines = off
|thrust = {{convert|2800000|lbf|kN|abbr=on|order=flip}}
|alt-thrust =
|time = 127 seconds
|fuel = [[Polybutadiene acrylonitrile|PBAN]]-[[Ammonium perchlorate composite propellant|APCP]]
}}

The '''Space Shuttle Solid Rocket Boosters''' ('''SRBs''') were the first [[solid fuel]] motors to be used for primary propulsion on a vehicle used for [[human spaceflight]]<ref>{{cite web | url = http://www.nasa.gov/returntoflight/system/system_SRB.html | title = NASA – Solid Rocket Boosters | publisher = NASA | archiveurl=https://web.archive.org/web/20130406193019/http://www.nasa.gov/returntoflight/system/system_SRB.html | archivedate = 2013-04-06}}</ref> and provided the majority of the [[Space Shuttle]]'s thrust during the first two minutes of flight. After burnout, they were jettisoned and parachuted into the Atlantic Ocean where they were [[recoverable booster|recovered]], examined, refurbished, and [[reusable launch system|reused]].

The SRBs were the most powerful solid rocket motors ever flown.<ref name="HaleAdministration2011">{{cite book|author1=Wayne Hale|author2=National Aeronautics and Space Administration|author3=Helen Lane |author4=Gail Chapline |author5=Kamlesh Lulla|title=Wings in Orbit: Scientific and Engineering Legacies of the Space Shuttle, 1971-2010|url=https://books.google.com/books?id=QczRqXWSWwMC&pg=PA5|date=7 April 2011|publisher=Government Printing Office|isbn=978-0-16-086847-4|pages=5}}</ref> Each provided a maximum {{convert|3100000|lbf|kN|abbr=on|order=flip|sigfig=3}} thrust, roughly double the most powerful single-[[combustion chamber]] [[liquid-propellant rocket]] engine ever flown, the [[Rocketdyne F-1]]. With a combined mass of about {{convert|1180000|kg|abbr=on}}, they comprised over half the mass of the Shuttle stack at liftoff. The motor segments of the SRBs were manufactured by [[Thiokol]] of [[Brigham City, Utah]], which was later purchased by [[Alliant Techsystems|ATK]]. The prime contractor for most other components of the SRBs, as well as for the integration of all the components and retrieval of the spent SRBs, was USBI, a subsidiary of [[Pratt and Whitney]]. This contract was subsequently transitioned to [[United Space Alliance]], a [[limited liability company]] joint venture of [[Boeing]] and [[Lockheed Martin]].

Out of 270 SRBs launched over the Shuttle program, all but four were recovered – those from [[STS-4]] (due to a parachute malfunction) and [[STS-51-L]] ([[Space Shuttle Challenger disaster|Challenger disaster]]).<ref>{{cite web|title=One year on – Review notes superb performance of STS-135’s SRBs|url=http://www.nasaspaceflight.com/2012/07/final-flight-superb-performance-sts-135s-srbs/|website=NASASpaceFlight.com|accessdate=February 26, 2015}}</ref> Over 5,000 parts were refurbished for reuse after each flight. The final set of SRBs that launched [[STS-135]] included parts that flew on 59 previous missions, including [[STS-1]].<ref>{{cite web|title=Booster stacking finished for final shuttle flight|url=http://www.spaceflightnow.com/shuttle/sts135/110418srbs/|website=Spaceflightnow.com|accessdate=February 26, 2015}}</ref> Recovery also allowed post-flight examination of the boosters,<ref>{{cite web|title=STS-134 IFA Review: SRBs and RSRMs Perform Admirably|url=http://www.nasaspaceflight.com/2011/06/sts-134-ifa-review-srbs-rsrms-perform-admirably/|website=NASASpaceFlight.com|accessdate=February 26, 2015}}</ref> identification of anomalies, and incremental design improvements.<ref name=RSRM-ALCS>{{cite web|title=Reusable Solid Rocket Motor—Accomplishments, Lessons, and a Culture of Success |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120001536.pdf |website=ntrs.nasa.gov |accessdate=February 26, 2015}}</ref>

==Overview==
[[File:Static Test Firing DM-2 for Solid Rocket Booster - GPN-2000-000053.jpg|thumb|Static test firing, 1978]]
[[File:STS-1 The Shuttle's Solid Rocket Boosters break away from Columbia's External Tank.jpg|thumb|right|210px|Solid Rocket Booster (SRB) separation]]
The two reusable SRBs provided the main thrust to lift the shuttle off the [[launch pad]] and up to an altitude of about {{convert|150000|ft|mi km|abbr=on}}. While on the pad, the two SRBs carried the entire weight of the external tank and [[Space Shuttle orbiter|orbiter]] and transmitted the weight load through their structure to the [[mobile launch platform]]. Each booster had a liftoff [[thrust]] of approximately {{convert|2800000|lbf|MN|lk=on}} at sea level, increasing shortly after liftoff to about {{convert|3100000|lbf|MN|abbr=on}}. They were ignited after the three [[Space Shuttle Main Engine]]s' thrust level was verified. Seventy-five seconds after SRB separation, SRB [[apogee]] occurred at an altitude of approximately {{convert|220000|ft|mi km|abbr=on}}; [[parachute]]s were then deployed and impact occurred in the ocean approximately {{convert|122|nmi|km|lk=on}} downrange, after which the two SRBs were recovered. The SRBs helped take the Space Shuttle to an altitude of 28 miles and a speed of 3,094 miles per hour along with the main engines.

The SRBs were the largest [[solid rocket|solid-propellant motors]] ever flown and the first of such large rockets designed for reuse. Each is {{convert|149.16|ft|m|abbr=on}} long and {{convert|12.17|ft|m|abbr=on}} in diameter.

The SRBs committed the shuttle to liftoff and ascent (to orbit) flight, without the possibility of launch or liftoff/ascent abort, until both motors had fully, and simultaneously, fulfilled their functions, consumed their propellants, were producing zero net reaction thrust and had been jettisoned (again simultaneously) by explosive jettisoning bolts from the remainder of the vehicle launch "stack" (shuttle w/engines; fuel/oxidizer tank). Only then could any conceivable set of launch or post-liftoff abort procedures be contemplated. In addition, failure of an individual SRB's thrust output or ability to adhere to the designed performance profile was not survivable.<ref> https://spaceflight.nasa.gov/outreach/SignificantIncidents/assets/rogers_commission_report.pdf</ref>

Each SRB weighed approximately {{convert|1300000|lb|kg|abbr=on}} at launch. The two SRBs constituted about 69% of the total lift-off mass. The [[propellant]] for each [[spacecraft propulsion|solid rocket motor]] weighed approximately {{convert|1100000|lb|kg|abbr=on}}. The inert weight of each SRB was approximately {{convert|200000|lb|kg}}.

Primary elements of each booster were the motor (including case, propellant, igniter, and [[rocket engine nozzle|nozzle]]), structure, separation systems, operational flight instrumentation, recovery avionics, [[pyrotechnics]], deceleration system, [[thrust vectoring|thrust vector]] control system, and [[range safety]] destruct system.

While the terms "solid rocket motor" and "solid rocket booster" are often used interchangeably, in technical use they have specific meanings. The term "solid rocket motor" applied to the propellant, case, igniter and nozzle. "Solid rocket booster" applied to the entire rocket assembly, which included the rocket motor as well as the recovery parachutes, electronic instrumentation, separation rockets, range safety destruct system, and thrust vector control.

Each booster was attached to the external tank at the SRB's aft frame by two lateral sway braces and a diagonal attachment. The forward end of each SRB was attached to the external tank at the forward end of the SRB's forward skirt. On the launch pad, each booster also was attached to the mobile launcher platform at the aft skirt by four [[frangible nut]]s that were severed at lift-off.

The boosters were composed of seven individually manufactured steel segments. These were assembled in pairs by the manufacturer, and then shipped to Kennedy Space Center by rail for final assembly. The segments were fixed together using circumferential tang, clevis, and [[clevis pin]] fastening, and sealed with [[O-ring]]s (originally two, changed to three after the [[Challenger Disaster|''Challenger'' Disaster]] in 1986) and heat-resistant putty.

==Components==
[[Image:Space Shuttle SRB diagram.png|500px|thumb|SRB Diagram]]

===Hold-down posts===
Each solid rocket booster had four hold-down posts that fit into corresponding support posts on the mobile launcher platform. Hold-down [[Screw|bolts]] held the SRB and launcher platform posts together. Each bolt had a nut at each end, the top one being a [[frangible nut]]. The top nut contained two [[NASA standard detonator]]s (NSDs), which were ignited at solid rocket motor ignition commands.

When the two NSDs were ignited at each hold down, the hold-down bolt traveled downward because of the release of tension in the bolt (pretensioned before launch), NSD gas pressure and gravity. The bolt was stopped by the stud deceleration stand, which contained sand. The SRB bolt was {{convert|28|in|mm|abbr=on}} long and {{convert|3.5|in|mm|abbr=on}} in diameter. The frangible nut was captured in a blast container.

The solid rocket motor ignition commands were issued by the orbiter's computers through the master events controllers to the hold-down pyrotechnic initiator controllers (PICs) on the [[mobile launcher platform]]. They provided the ignition to the hold-down NSDs. The launch processing system monitored the SRB hold-down PICs for low voltage during the last 16 seconds before launch. PIC low voltage would initiate a launch hold.

===Electrical power distribution===
Electrical power distribution in each SRB consisted of orbiter-supplied main [[Direct current|DC]] bus power to each SRB via SRB buses labeled A, B and C. Orbiter main DC buses A, B and C supplied main DC bus power to corresponding SRB buses A, B and C. In addition, orbiter main DC bus C supplied backup power to SRB buses A and B, and orbiter bus B supplied backup power to SRB bus C. This electrical power distribution arrangement allowed all SRB buses to remain powered in the event one orbiter main bus failed.

The nominal operating voltage was 28±4 volts DC.

===Hydraulic power units===
There were two self-contained, independent Hydraulic Power Units (HPUs) on each SRB. Each HPU consisted of an [[auxiliary power unit]] (APU), fuel supply module, [[hydraulic]] [[pump]], hydraulic reservoir and [[hydraulic fluid]] manifold assembly. The APUs were fueled by [[hydrazine]] and generated mechanical shaft power to drive a hydraulic pump that produced hydraulic pressure for the SRB hydraulic system. The two separate HPUs and two hydraulic systems were located on the aft end of each SRB between the SRB nozzle and aft skirt. The HPU components were mounted on the aft skirt between the rock and tilt actuators. The two systems operated from T minus 28 seconds until SRB separation from the orbiter and external tank. The two independent hydraulic systems were connected to the rock and tilt [[Servomechanism|servo]]actuators.

The HPU controller electronics were located in the SRB aft integrated electronic assemblies on the aft external tank attach rings.

The HPUs and their fuel systems were isolated from each other. Each fuel supply module (tank) contained {{convert|22|lb|kg|abbr=on}} of hydrazine. The fuel tank was pressurized with gaseous nitrogen at {{convert|400|psi|MPa|abbr=on|lk=on}}, which provided the force to expel (positive expulsion) the fuel from the tank to the fuel distribution line, maintaining a positive fuel supply to the APU throughout its operation.

In the APU, a fuel pump boosted the hydrazine pressure and fed it to a gas generator. The gas generator [[catalytic]]ally decomposed the hydrazine into hot, high-pressure gas; a two-stage turbine converted this into mechanical power, driving a gearbox. The waste gas, now cooler and at low pressure, was passed back over the gas generator housing to cool it before being dumped overboard. The gearbox drove the fuel pump, its own lubrication pump, and the HPU hydraulic pump. As described so far, the system could not self-start, since the fuel pump was driven by the turbine it supplied fuel to. Accordingly, a bypass line went around the pump and fed the gas generator using the nitrogen tank pressure until the APU speed was such that the fuel pump outlet pressure exceeded that of the bypass line, at which point all the fuel was supplied to the fuel pump.

When the APU speed reached 100%, the APU primary control valve closed, and the APU speed was controlled by the APU controller electronics. If the primary control valve logic failed to the open state, the secondary control valve assumed control of the APU at 112% speed.

Each HPU on an SRB was connected to both [[Servomechanism|servo]]actuators on that SRB by a switching valve that allowed the hydraulic power to be distributed from either HPU to both actuators if necessary. Each HPU served as the primary hydraulic source for one servoactuator, and a secondary source for the other servoactuator. Each HPU possessed the capacity to provide hydraulic power to both servoactuators within %115 operational limits in the event that hydraulic pressure from the other HPU should drop below {{convert|2050|psi|MPa|abbr=on}}. A switch contact on the switching valve closed when the valve was in the secondary position. When the valve was closed, a signal was sent to the APU controller, that inhibited the 100% APU speed control logic and enabled the 112% APU speed control logic. The 100-percent APU speed enabled one APU/HPU to supply sufficient operating hydraulic pressure to both servoactuators of that SRB.

The APU 100-percent speed corresponded to 72,000 rpm, 110% to 79,200 rpm, and 112% to 80,640 rpm.

The hydraulic pump speed was 3,600 rpm and supplied hydraulic pressure of {{convert|3050|+/-|50|psi|MPa|abbr=on}}. A high pressure [[relief valve]] provided overpressure protection to the hydraulic system and relieved at {{convert|3750|psi|MPa|abbr=on}}.

The APUs/HPUs and hydraulic systems were reusable for 20 missions.

===Thrust vector control===
{{further|thrust vectoring}}
Each SRB had two [[hydraulic]] [[gimbal]] servoactuators, to move the nozzle up/down and side-to-side. This provided [[thrust vectoring]] to help control the vehicle in all three axes (roll, pitch, and yaw).

The ascent thrust vector control portion of the flight control system directed the thrust of the three shuttle main engines and the two SRB nozzles to control shuttle attitude and trajectory during lift-off and ascent. Commands from the guidance system were transmitted to the ATVC (Ascent Thrust Vector Control) drivers, which transmitted signals proportional to the commands to each servoactuator of the main engines and SRBs. Four independent flight control system channels and four ATVC channels controlled six main engine and four SRB ATVC drivers, with each driver controlling one hydraulic port on each main and SRB servoactuator.

Each SRB servoactuator consisted of four independent, two-stage servovalves that received signals from the drivers. Each servovalve controlled one power spool in each actuator, which positioned an actuator ram and the nozzle to control the direction of thrust.

The four servovalves in each actuator provided a "force-summed majority voting" arrangement to position the power spool. With four identical commands to the four servovalves, the actuator force-sum action prevented a single erroneous command from affecting power ram motion. If the erroneous command persisted for more than a predetermined time, differential pressure sensing activated a selector valve to isolate and remove the defective servovalve hydraulic pressure, permitting the remaining channels and servovalves to control the actuator ram spool.

Failure monitors were provided for each channel to indicate which channel had been bypassed. An isolation valve on each channel provided the capability of resetting a failed or bypassed channel.

Each actuator ram was equipped with [[transducer]]s for position feedback to the thrust vector control system. Within each servoactuator ram was a splashdown load relief assembly to cushion the nozzle at water splashdown and prevent damage to the nozzle flexible bearing.

===Rate gyro assemblies===
Each SRB contained three [[Rate gyro]] assemblies (RGAs), with each RGA containing one pitch and one yaw gyro. These provided an output proportional to angular rates about the pitch and yaw axes to the orbiter computers and guidance, navigation and control system during first-stage ascent flight in conjunction with the orbiter roll rate gyros until SRB separation. At SRB separation, a switchover was made from the SRB RGAs to the orbiter RGAs.

The SRB RGA rates passed through the orbiter flight aft multiplexers/demultiplexers to the orbiter GPCs. The RGA rates were then mid-value-selected in redundancy management to provide SRB pitch and yaw rates to the user software. The RGAs were designed for 20 missions.

===Propellant===
[[File:STS-134 solid rocket booster segment stacking.jpg|thumb|left|Sections of the SRB filled with propellant being connected]]
The [[rocket propellant]] mixture in each solid rocket motor consisted of [[ammonium perchlorate]] ([[oxidizer]], 69.6% by weight), atomized [[aluminum]] powder ([[fuel]], 16%), [[iron oxide]] ([[catalyst]], 0.4%), [[Polybutadiene acrylonitrile|PBAN]] (binder, also acts as fuel, 12.04%), and an [[epoxy]] curing agent (1.96%).<ref name="sts-newsref-srb">{{cite web | url = http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html | title = Solid Rocket Boosters | website = NASA |access-date=June 28, 2016}}</ref><ref name="returntoflight-system-SRB">{{cite web | url = http://www.nasa.gov/returntoflight/system/system_SRB.html | title = Solid Rocket Boosters | website = NASA | access-date=June 28, 2016}}</ref> This propellant is commonly referred to as ''[[Ammonium Perchlorate Composite Propellant]]'', or simply APCP. This mixture gave the solid rocket motors a [[specific impulse]] of {{convert|242|isp}} at sea level or {{convert|268|isp}} in a vacuum.

The main fuel, aluminum, was used because it has a reasonable specific energy density of about 31.0 MJ/kg, but a high volumetric energy density, and is difficult to ignite accidentally.

The propellant had an 11-point [[star polygon|star]]-shaped perforation in the forward motor segment and a double-truncated-[[cone (geometry)|cone]] perforation in each of the aft segments and aft closure. This configuration provided high thrust at ignition and then reduced the thrust by approximately a third 50 seconds after lift-off to avoid [[Stress (mechanics)|overstressing]] the vehicle during [[Max Q|maximum dynamic pressure]] (Max Q).<ref name="sts-newsref-srb"/>

==Function==
[[Image:Srbthrust2.svg|right|400px|thumb|SRB Sea Level Thrust. Data from [[STS-107]]]]

===Ignition===
SRB ignition can occur only when a manual lock pin from each SRB safe and arm device has been removed. The ground crew removes the pin during prelaunch activities. At T minus five minutes, the SRB safe and arm device is rotated to the arm position. The solid rocket motor ignition commands are issued when the three [[Space Shuttle Main Engine]]s (SSMEs) are at or above 90-percent rated thrust, no SSME fail and/or SRB ignition [[Pyrotechnic]] Initiator Controller (PIC) low voltage is indicated and there are no holds from the Launch Processing System (LPS).

The solid rocket motor ignition commands are sent by the orbiter computers through the Master Events Controllers (MECs) to the safe and arm device [[NASA standard detonator|NASA standard detonators ("NSD"s)]] in each SRB. A PIC single-channel capacitor discharge device controls the firing of each pyrotechnic device. Three signals must be present simultaneously for the PIC to generate the pyro firing output. These signals — arm, fire 1 and fire 2 — originate in the [[IBM AP-101|orbiter general-purpose computers]] (GPCs) and are transmitted to the MECs. The MECs reformat them to 28 volt DC signals for the PICs. The arm signal charges the PIC capacitor to 40 volts DC (minimum of 20 volts DC).

The GPC launch sequence also controls certain critical main propulsion system valves and monitors the engine ready indications from the SSMEs. The MPS start commands are issued by the onboard computers at T minus 6.6 seconds (staggered start engine three, engine two, engine one all approximately within 0.25 of a second), and the sequence monitors the thrust buildup of each engine. All three SSMEs must reach the required 90% thrust within three seconds; otherwise, an orderly shutdown is commanded and safing functions are initiated.

Normal thrust buildup to the required 90% thrust level will result in the SSMEs being commanded to the lift off position at T minus three seconds as well as the fire 1 command being issued to arm the SRBs. At T minus three seconds, the vehicle base bending load modes are allowed to initialize (referred to as the "twang", movement of approximately {{convert|25.5|in|mm|abbr=on}} measured at the tip of the external tank, with movement towards the external tank).

The fire 2 commands cause the redundant NSDs to fire through a thin barrier seal down a flame tunnel. This ignites a pyro booster charge, which is retained in the safe and arm device behind a perforated plate. The booster charge ignites the propellant in the igniter initiator; and combustion products of this propellant ignite the solid rocket motor initiator, which fires down the entire vertical length of the solid rocket motor igniting the solid rocket motor propellant along its entire surface area instantaneously.

At T minus zero, the two SRBs are ignited, under command of the four onboard computers; separation of the four [[explosive bolts]] on each SRB is initiated; the two T-0 umbilicals (one on each side of the spacecraft) are retracted; the onboard master timing unit, event timer and mission event timers are started; the three SSMEs are at 100%; and the ground launch sequence is terminated.

===Lift-off and ascent===
Timing sequence referencing in ignition is critical for a successful liftoff and ascent flight. The explosive hold-down bolts relieve (through the launch support pedestals and pad structure) the asymmetric vehicle dynamic loads caused by the SSME ignition and thrust buildup, and applied thrust bearing loads. Without the hold-down bolts the SSMEs would violently tip the flight stack (orbiter, external tank, SRBs) over onto the external tank. That rotating moment is initially countered by the hold-bolts. Prior to release of the vehicle stack for liftoff, the SRBs must simultaneously ignite and pressurize their combustion chambers and exhaust nozzles to produce a thrust derived, net counter-rotating moment exactly equal to the SSME’s rotating moment. With the SRBs reaching full thrust, the hold-down bolts are blown, releasing the vehicle stack, the net rotating moment is zero, and the net vehicle thrust (opposing gravity) is positive, lifting the orbiter stack vertically from the launch pedestal, controllable through the coordinated [[gimbal]] movements of the SSMEs and the SRB exhaust nozzles.

During ascent, multiple all-axis accelerometers detect and report the vehicle's flight and orientation (referencing the flight deck aboard the orbiter), as the flight reference computers translate navigation commands (steering to a particular waypoint in space, and at a particular time) into engine and motor nozzle gimbal commands, which orient the vehicle about its center of mass. As the forces on the vehicle change due to propellant consumption, increasing speed, changes in aerodynamic drag, and other factors, the vehicle automatically adjusts its orientation in response to its dynamic control command inputs.

The net result is a relatively smooth and constant (then gradually decreasing) gravitational pull due to acceleration, coupled with a diminishing aerodynamic friction as the upper atmosphere is reached and surpassed.

===Separation===
The SRBs are jettisoned from the space shuttle at high altitude, about {{convert|146000|ft|km|abbr=on}}. SRB separation is initiated when the three solid rocket motor chamber pressure transducers are processed in the redundancy management middle value select and the head-end chamber pressure of both SRBs is less than or equal to {{convert|50|psi|kPa|abbr=on}}. A backup cue is the time elapsed from booster ignition.

The separation sequence is initiated, commanding the thrust vector control actuators to the null position and putting the main propulsion system into a second-stage configuration (0.8 second from sequence initialization), which ensures the thrust of each SRB is less than {{convert|100000|lbf|kN|abbr=on}}. Orbiter yaw attitude is held for four seconds, and SRB thrust drops to less than {{convert|60000|lbf|kN|abbr=on}}.

The SRBs separate from the external tank within 30 milliseconds of the ordnance firing command.

The forward attachment point consists of a ball (SRB) and socket (External Tank (ET)) held together by one bolt. The bolt contains one NSD pressure cartridge at each end. The forward attachment point also carries the range safety system cross-strap wiring connecting each SRB RSS and the ET RSS with each other.

The aft attachment points consist of three separate struts: upper, diagonal and lower. Each strut contains one bolt with an NSD pressure cartridge at each end. The upper strut also carries the umbilical interface between its SRB and the external tank and on to the orbiter.

There are four [[booster separation motor]]s on each end of each SRB. The BSMs separate the SRBs from the external tank. The solid rocket motors in each cluster of four are ignited by firing redundant NSD pressure cartridges into redundant confined detonating fuse manifolds.

The separation commands issued from the orbiter by the SRB separation sequence initiate the redundant NSD pressure cartridge in each bolt and ignite the BSMs to effect a clean separation.

===Range safety system===
A [[range safety]] system (RSS) provides for destruction of a rocket or part of it with on-board explosives by remote command if the rocket is out of control, in order to limit the danger to people on the ground from crashing pieces, explosions, fire, poisonous substances, etc. The RSS was only activated once – during the [[Space Shuttle Challenger disaster|Space Shuttle ''Challenger'' disaster]] (37 seconds after the breakup of the vehicle, when the SRBs were in uncontrolled flight).

The shuttle vehicle had two RSSs, one in each SRB. Both were capable of receiving two command messages (arm and fire) transmitted from the ground station. The RSS was used only when the shuttle vehicle violates a launch trajectory red line.

An RSS consists of two antenna couplers, command receivers/decoders, a dual distributor, a safe and arm device with two [[NASA standard detonator]]s (NSD), two confined detonating fuse manifolds (CDF), seven CDF assemblies and one linear-shaped charge (LSC).

The antenna couplers provide the proper impedance for radio frequency and ground support equipment commands. The command receivers are tuned to RSS command frequencies and provide the input signal to the distributors when an RSS command is sent. The command decoders use a code plug to prevent any command signal other than the proper command signal from getting into the distributors. The distributors contain the logic to supply valid destruct commands to the RSS pyrotechnics.

The NSDs provide the spark to ignite the CDF, which in turn ignites the LSC for booster destruction. The safe and arm device provides mechanical isolation between the NSDs and the CDF before launch and during the SRB separation sequence.

The first message, called arm, allows the onboard logic to enable a destruct and illuminates a light on the flight deck display and control panel at the commander and pilot station. The second message transmitted is the fire command.

The SRB distributors in the SRBs are cross-strapped together. Thus, if one SRB received an arm or destruct signal, the signal would also be sent to the other SRB.

Electrical power from the RSS battery in each SRB is routed to RSS system A. The recovery battery in each SRB is used to power RSS system B as well as the recovery system in the SRB. The SRB RSS is powered down during the separation sequence, and the SRB recovery system is powered up.
<ref>{{cite web|url=http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html#srb-safety |title=Solid Rocket Boosters |publisher=NASA |accessdate=2010-08-28 | archiveurl=https://web.archive.org/web/20100725220547/http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html | archivedate=2010-07-25}}</ref>

===Descent and recovery===
[[File:Srb splashdown.jpg|thumb|Splashdown of the right hand SRB from the launch of [[STS-124]].]]The SRBs are jettisoned from the shuttle system at 2 minutes and an altitude of about 146,000 feet (44 km). After continuing to rise to about 220,000 feet (67 km), the SRBs begin to fall back to earth and once back in the denser atmosphere are slowed by a parachute system to prevent damage on ocean impact. A command is sent from the orbiter to the SRB just before separation to apply battery power to the recovery logic network. A second, simultaneous command arms the three nose cap thrusters (for deploying the pilot and [[drogue parachute]]), the [[frustum]] ring detonator (for main parachute deployment), and the main parachute disconnect ordnance.

The recovery sequence begins with the operation of the high-altitude [[baroswitch]], which triggers the pyrotechnic nose cap thrusters. This ejects the nose cap, which deploys the [[pilot chute|pilot parachute]]. Nose cap separation occurs at a nominal altitude of {{convert|15704|ft|m|abbr=on}}, about 218 seconds after SRB separation. The {{convert|11.5|ft|m|abbr=on|adj=on}} diameter conical ribbon pilot parachute provides the force to pull lanyards attached to cut knives, which cut the loop securing the [[drogue parachute|drogue]] retention straps. This allows the pilot chute to pull the drogue pack from the SRB, causing the drogue suspension lines to deploy from their stored position. At full extension of the twelve {{convert|105|ft|m|abbr=on}} suspension lines, the drogue deployment bag is stripped away from the canopy, and the {{convert|54|ft|m|abbr=on|adj=on}} diameter conical ribbon drogue parachute inflates to its initial reefed condition. The drogue disreefs twice after specified time delays (using redundant 7 and 12-second reefing line cutters), and it reorients/stabilizes the SRB for main chute deployment. The drogue parachute has a design load of approximately {{convert|315000|lb|kg|abbr=on}} and weighs approximately {{convert|1200|lb|kg|abbr=on}}.

[[Image:STS-116 rocket boosters (NASA KSC-06PD-2794).jpg|thumb|The solid rocket boosters, jettisoned from the [[Space Shuttle Discovery|Space Shuttle ''Discovery'']] following the launch of [[STS-116]], floating in the Atlantic Ocean about 150 miles northeast of [[Cape Canaveral]]. On this occasion, the boosters landed several miles apart, but overnight winds and currents drifted them to the same location]]After the drogue chute has stabilized the SRB in a tail-first attitude, the frustum is separated from the forward skirt by a pyrotechnic charge triggered by the low-altitude baroswitch at a nominal altitude of {{convert|5500|ft|m|abbr=on}} about 243 seconds after SRB separation. The frustum is then pulled away from the SRB by the drogue chute. The main chute suspension lines are pulled out from deployment bags that remain in the frustum. At full extension of the lines, which are {{convert|203|ft|m|abbr=on}} long, the three main chutes are pulled from their deployment bags and inflate to their first reefed condition. The frustum and drogue parachute continue on a separate trajectory to splashdown. After specified time delays (using redundant 10 and 17-second reefing line cutters), the main chute reefing lines are cut and the chutes inflate to their second reefed and full open configurations. The main chute cluster decelerates the SRB to terminal conditions. Each of the {{convert|136|ft|m|abbr=on}} diameter, 20-degree conical ribbon parachutes have a design load of approximately {{convert|195000|lb|kg|abbr=on}} and each weighs approximately {{convert|2180|lb|kg|abbr=on}}. These parachutes are the largest that have ever been used — both in deployed size and load weight. The RSRM nozzle extension is severed by a pyrotechnic charge about 20 seconds after frustum separation.

Water impact occurs about 279 seconds after SRB separation at a nominal velocity of {{convert|76|ft/s|m/s}}. The water impact range is approximately {{convert|130|nmi|km|abbr=on}} off the eastern coast of [[Florida]]. Because the parachutes provide for a nozzle-first impact, air is trapped in the empty (burned out) motor casing, causing the booster to float with the forward end approximately {{convert|30|ft|m}} out of the water.

[[File:Freedom Star with SRB.JPG|thumb|Solid rocket booster of the [[STS-131]] mission being recovered and transported to Cape Canaveral by the {{MV|Freedom Star}}.]]

Formerly, the main chutes were released from the SRB at impact using a parachute release nut ordnance system (residual loads in the main chutes would deploy the parachute attach fittings with floats tethered to each fitting). The current design keeps the main chutes attached during water impact (initial impact and slapdown). Salt Water Activated Release (SWAR) devices are now incorporated into the main chute riser lines to simplify recovery efforts and reduce damage to the SRB.<ref>{{cite web | url=http://www.spaceflight.nasa.gov/shuttle/upgrades/swar.html | title= Salt Water Activated Release for the SRB Main Parachutes (SWAR) | date=2002-04-07 | publisher=NASA | archiveurl=https://web.archive.org/web/20020203162534/http://spaceflight.nasa.gov/shuttle/upgrades/swar.html | archivedate=2002-02-03}}</ref> The drogue deployment bag/pilot parachutes, drogue parachutes and frustums, each main chute, and the SRBs are buoyant and are recovered.

Specially fitted [[NASA recovery ship]]s, the {{MV|Freedom Star}} and the {{MV|Liberty Star}}, recover the SRBs and descent/recovery hardware. Once the boosters are located, the Diver Operated Plug (DOP) is maneuvered by divers into place to plug the SRB nozzle and drain the water from the motor case. Pumping air into and water out of the SRB causes the SRB to change from a nose-up floating position to a horizontal attitude more suitable for towing. The retrieval vessels then tow the boosters and other objects recovered back to [[Kennedy Space Center]].

==Challenger disaster==
{{Main|Space Shuttle Challenger disaster}}
[[Image:STS-51-L grey smoke on SRB.jpg|thumb|left|Camera captures grey smoke being emitted from the right-hand SRB on [[Space Shuttle Challenger|Space Shuttle ''Challenger'']] before the start of [[STS-51-L]].]]
The loss of Space Shuttle ''Challenger'' originated with a system failure of one of its SRBs. The cause of the accident was found by the [[Rogers Commission Report|Rogers Commission]] to be "a faulty design unacceptably sensitive to a number of factors" of the SRB joints compounded by unusually cold weather the morning of the flight.<ref>{{cite web | url=https://history.nasa.gov/rogersrep/v1ch4.htm | title=Report of the Presidential Commission on the Space Shuttle ''Challenger'' Accident, Chapter IV: The Cause of the Accident | publisher = NASA | archiveurl=https://web.archive.org/web/20130511035132/https://history.nasa.gov/rogersrep/v1ch4.htm |archivedate=2013-05-11 }}</ref><ref>{{cite web | url=http://choo.fis.utoronto.ca/mgt/DM.case.html | title= Space Shuttle Challenger Case}}</ref> The commission found that the large rubber "O-rings" in SRB joints were not effective at low temperatures like those of the January 1986 morning of the accident ({{convert|36|F|C|lk=off|sigfig=2}}). A cold-compromised joint in the right SRB failed at launch and eventually allowed hot gases from within that rocket booster to sear a hole into the adjacent main external fuel tank and also weaken the lower strut holding the SRB to the external tank. The leak in the SRB joint caused a catastrophic failure of the lower strut and partial detachment of the SRB, which led to a collision between the SRB and the external tank. With a disintegrating external tank and severely off-axis thrust from the right SRB, traveling at a speed of Mach 1.92 at {{convert|46,000|ft|km}}, the Space Shuttle stack disintegrated and was enveloped in an "explosive burn" (i.e. rapid [[deflagration]]) of the liquid propellants from the external tank.<ref name="history.nasa.gov">{{cite web | url=https://history.nasa.gov/rogersrep/v1ch3.htm | title=Report of the Presidential Commission on the Space Shuttle ''Challenger'' Accident, Chapter III: The Accident | publisher = NASA}}</ref> Concerns were briefed by the SRB manufacturer due to the cold temperatures, but were overridden due to resistance from NASA managers to change launch criteria at such a late stage in launch preparation.

During the subsequent downtime, detailed structural analyses were performed on critical structural elements of the SRB. Analyses were primarily focused in areas where anomalies had been noted during postflight inspection of recovered hardware.

One of the areas was the attachment ring where the SRBs are connected to the external tank. Areas of distress were noted in some of the fasteners where the ring attaches to the SRB motor case. This situation was attributed to the high loads encountered during water impact. To correct the situation and ensure higher strength margins during ascent, the attach ring was redesigned to encircle the motor case completely (360 degrees). Previously, the attachment ring formed a 'C' shape and encircled the motor case just 270 degrees.
[[File:Booster Rocket Breach - GPN-2000-001425.jpg|thumb|upright|The right SRB shows an anomalous plume at T+ 58.788 seconds. This plume would trigger the breakup of the vehicle 14 seconds later.]]
Additionally, special structural tests were performed on the aft skirt. During this test program, an anomaly occurred in a critical [[welding|weld]] between the hold-down post and skin of the skirt. A redesign was implemented to add reinforcement brackets and fittings in the aft ring of the skirt.

These two modifications added approximately {{convert|450|lb|kg|abbr=on}} to the weight of each SRB. The result is called a "Redesigned Solid Rocket Motor" (RSRM).<ref>{{cite web | url = http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_asm.html#srb_mods | title = Orbiter Manufacturing and Assembly | publisher = NASA}}</ref>

==Construction==
The prime contractor for the SRB motor segments was [[Thiokol|ATK Launch Systems]]' Wasatch Division based in [[Magna, Utah]].

United Space Boosters Inc. (USBI), a division of Pratt and Whitney, under United Technologies, was the original SRB prime contractor for SRB assembly, checkout and refurbishment for all non-solid-rocket-motor components and for SRB integration. They were the longest running prime contractor for the Space Shuttle that was part of the original launch team. USBI was absorbed by United Space Alliance as the Solid Rocket Booster Element division in 1998 and the USBI division was disbanded at Pratt & Whitney the following year. At its peak, USBI had over 1500 personnel working on the Shuttle Boosters at KSC, FL and Huntsville, AL.

Many other companies supplied various components for the SRBs:{{Citation needed|date=October 2012}}
* [[Parker-Abex Corp.]] of [[Kalamazoo, Michigan]] (hydraulic pumps)
* [[Aerojet]] of [[Redmond, Washington]] (hydrazine gas generators)
* [[Arde Inc.]] of [[Mahwah, New Jersey]] (hydrazine fuel supply modules)
* [[Arkwin Industries Inc.]] of [[Westbury, New York]] (hydraulic reservoirs)
* [[Aydin Vector Division]] of [[Newtown Township, Bucks County, Pennsylvania|Newtown, Pennsylvania]] (integrated electronic assemblies)
* [[Bendix Corp.]] of [[Teterboro, New Jersey]] (integrated electronic assemblies)
* [[Consolidated Controls Corp.]] of [[El Segundo, California]] (hydrazine)
* [[Eldec Corp.]] of [[Lynnwood, Washington]] (integrated electronic assemblies)
* [[Explosive Technology]] of [[Fairfield, California]] (CDF manifolds)
* [[Gaco Western]] of [[Seattle, Washington]] (Hypalon Paint)
* [[Lockheed Martin]] (formerly [[Martin Marietta]]) of [[Denver, Colorado]] (pyro initiator controllers)
* [[Moog Inc.]] of [[East Aurora, New York]] (servoactuators, fuel isolation valves)
* [[Motorola]] of [[Scottsdale, Arizona]] (range safety receivers)
* [[Pioneer Parachute Company]] of [[Manchester, Connecticut]] (parachutes)
* [[Sperry Rand Flight Systems]] of [[Phoenix, Arizona]] (multiplexers / demultiplexers)
* [[Teledyne]] of [[Lewisburg, Tennessee]] (location aid transmitters)
* [[ATK Launch Systems Corp.]] of [[Brigham City, Utah]] (separation motors)
* [[Hamilton Sundstrand]] of [[Windsor Locks, Connecticut]] (auxiliary power units)
* [[VACCO Industries]] of [[El Monte, California|South El Monte, California]] (safe and arm device)
* [[Voss Industries]] of [[Cleveland, Ohio]] (SRB Retention Bands)

==Advanced Solid Rocket Motor (ASRM) Project==
NASA was planning on replacing the post-''Challenger'' SRBs with a new Advanced Solid Rocket Motor (ASRM) to be built by [[Aerojet]]<ref>Leary, Warren E., [https://www.nytimes.com/1989/04/22/business/nasa-picks-lockheed-and-aerojet.html ''NASA Picks Lockheed and Aerojet''], New York Times, April 22, 1989</ref> at a new facility, designed by subcontractor, RUST International, on the location of a canceled [[Tennessee Valley Authority]] nuclear power plant, at Yellow Creek, Mississippi. The ASRM would have produced additional thrust in order to increase shuttle payload, so that it could carry modules and construction components to the ISS. The ASRM program was canceled in 1993 after robotic assembly systems and computers were on-site and approximately 2 billion dollars spent, in favor of continued use, after design flaw corrections, of the SRB.

==Filament-wound cases==
In order to provide the necessary performance to launch polar-orbiting shuttles from the [[SLC-6]] launch pad at [[Vandenberg Air Force Base]] in [[California]], SRBs using ''[[filament winding|filament-wound]] cases'' (FWC) were designed to be more lightweight than the steel cases used on Kennedy Space Center-launched SRBs.<ref name="ross">"[http://www.jsc.nasa.gov/history/oral_histories/RossJL/RossJL_1-26-04.pdf Jerry L. Ross]" NASA Johnson Space Center Oral History Project, 26 January 2004.</ref> Unlike the regular SRBs, which had the flawed field joint design that led to the ''Challenger'' Disaster in 1986, the FWC boosters had the "double tang" joint design (necessary to keep the boosters properly in alignment during the "twang" movement when the SSMEs are ignited prior to liftoff), but used the two O-ring seals. With the closure of SLC-6, the FWC boosters were scrapped by ATK and NASA, but their field joints, albeit modified to incorporate the current three O-ring seals and joint heaters, were later incorporated into the present-day field joints on the current SRBs.

==Five-segment booster==
Prior to the destruction of the [[Space Shuttle Columbia|Space Shuttle ''Columbia'']] in 2003, NASA investigated the replacement of the current 4-segment SRBs with either a 5-segment SRB design or replacing them altogether with liquid "flyback" boosters using either [[Atlas V]] or [[Delta IV]] EELV technologies. The 5-segment SRB, which would have required little change to the current shuttle infrastructure, would have allowed the space shuttle to carry an additional {{convert|20000|lbs|kg|abbr=on}} of payload in an [[International Space Station]]-inclination orbit, eliminate the dangerous [[Space Shuttle abort modes|"Return-to-Launch Site" (RTLS) and "Trans-Oceanic Abort]]" (TAL) modes, and, by using a so-called "dog-leg maneuver", fly south-to-north polar orbiting flights from Kennedy Space Center. After the destruction of ''Columbia'', NASA shelved the five-segment SRB for the Shuttle Program, and the three surviving Orbiters, [[Space Shuttle Discovery|''Discovery'']], [[Space Shuttle Atlantis|''Atlantis'']], and [[Space Shuttle Endeavour|''Endeavour'']] were retired in 2011 after the completion of the [[International Space Station]].<ref>Jenkins, Dennis R. "Space Shuttle: History of the National Space Transportation System – The First 100 Flights"</ref> One five-segment engineering test motor, ETM-03, was fired on October 23, 2003.<ref>{{cite web |url=http://www.csar.illinois.edu/F_viz/gallery/AIAA/RSRMV/McMillinETM-03-AIAA-2004-3895.pdf |title=A Review of ETM-03 (A Five Segment Shuttle RSRM Configuration) Ballistic Performance |author=J. E. McMillin and J. A. Furfaro |deadurl=yes |archiveurl=https://web.archive.org/web/20110719211113/http://www.csar.illinois.edu/F_viz/gallery/AIAA/RSRMV/McMillinETM-03-AIAA-2004-3895.pdf |archivedate=2011-07-19 |df= }}</ref><ref>{{cite web |url=http://www.nasa.gov/centers/marshall/news/news/releases/2003/03-186.html |title=Most powerful Space Shuttle Solid Rocket Motor ever tested proves it can be pushed close to edge, yet still perform flawlessly |publisher=NASA MSFC}}</ref>

As part of the Constellation Program, the first stage of the [[Ares I]] rocket was planned to use five-segment SRBs – in September 2009 a five-segment Space Shuttle SRB was static fired on the ground in ATK's desert testing area in Utah.<ref name="NASA">{{cite web|url=http://www.nasa.gov/mission_pages/constellation/ares/dm1_success.html |title=NASA and ATK Successfully Test Ares First Stage Motor |publisher=NASA |accessdate=2010-03-25 | archiveurl=https://web.archive.org/web/20100325103340/http://www.nasa.gov/mission_pages/constellation/ares/dm1_success.html | archivedate=2010-03-25}}</ref>

After the Constellation Program was cancelled in 2011, the new [[Space Launch System]] (SLS) was designated to use five-segment boosters. The first test of a SRB for SLS was completed in early 2015, a second test was performed in mid 2016 at Orbital ATK's Promontory, Utah facility.<ref>{{cite web|url=https://www.orbitalatk.com/news-room/release.asp?prid=147|title=News Room|author=|date=|website=www.orbitalatk.com|accessdate=4 April 2018}}</ref>

==Displays==
Space Shuttle Solid Rocket Boosters are on display at the [[Kennedy Space Center Visitors Complex]] in Florida, the [[Stennis Space Center]] in Hancock County, Mississippi, the [[United States Space & Rocket Center]] in Huntsville, Alabama, and at [[Orbital ATK]]'s facility near [[Promontory, Utah]].<ref>{{cite web|title=Launch Vehicles|url=http://web.mac.com/jimgerard/AFGAS/pages/booster/index.html|work=A Field Guide to American Spacecraft|deadurl=yes|archiveurl=https://web.archive.org/web/20100312030139/http://web.mac.com/jimgerard/AFGAS/pages/booster/index.html|archivedate=2010-03-12|df=}}</ref>
A partial filament-wound booster case is on display at [[Pima Air & Space Museum]] in [[Tucson, Arizona]].<ref>{{cite web|title=“Space shuttle solid rocket booster arrives for display at Arizona museum|url=http://www.collectspace.com/news/news-122916a-pima-air-space-museum-rocket-booster.html|website=Pima Air & Space Museum|publisher=|accessdate=September 18, 2018}}</ref>

==Future and proposed uses==
[[Image:Ares I-X launch 08.jpg|thumb|The Ares I-X prototype launches from LC-39B, 15:30 UTC, October 28, 2009 – this was as of 2016 the sole flight of a launch vehicle [[wikt:derived|derived]] from the SRB.]]
Over time several proposals to reuse the SRB design were presented – however, as of 2016 none of these proposals progressed to regular flights before being cancelled. Until the [[Exploration Mission 1|2019 planned first flight]] of the [[Space Launch System]] (SLS), a sole test-flight of the [[Ares I-X]] prototype in 2009 was the furthest any of these proposals progressed.

===Ares===
NASA initially planned to reuse the four-segment SRB design and infrastructure in several Ares rockets, which would have propelled the Orion spacecraft into orbit. In 2005, NASA announced the [[Shuttle-Derived Launch Vehicle]] slated to carry the [[Orion spacecraft|Orion]] Crew Exploration Vehicle into low-Earth orbit and later to the Moon. The SRB-derived Crew Launch Vehicle (CLV), named [[Ares I]], was planned to feature a single modified four-segment SRB for its first stage; a single liquid-fueled modified [[Space Shuttle Main Engine]] would have powered the second stage.

The Ares I design updated in 2006 featured one five-segment SRB (originally developed for the Shuttle, but never used) as a first stage – the second stage was powered by an uprated [[J-2 (rocket engine)|J-2X]] engine, derived from the [[Rocketdyne J-2|J-2]], which had been used in the upper stage of [[Saturn V]] and [[Saturn IB]]. In place of the standard SRB nosecone, the Ares I would have a tapered interstage assembly connecting the booster proper with the second stage, an attitude control system derived from the [[Regulus missile]] system, and larger, heavier parachutes to lower the stage into the Atlantic Ocean for recovery.

Also introduced in 2005, was a [[Heavy Lift Launch Vehicle|heavy-lift]] Cargo Launch Vehicle (CaLV) named [[Ares V]]. Early designs of the Ares V utilized ''five'' standard-production SSMEs and a pair of 5-segment boosters identical to those proposed for the Shuttle, while later plans redesigned the boosters around the [[RS-68]] rocket engine used on the Delta IV EELV system. Initially, NASA switched over to a system using the 5-segment boosters and a cluster of five RS-68s (which resulted in a widening of the Ares V core unit), then NASA reconfigured the vehicle with six RS-68B engines, with the boosters themselves becoming "5.5-Segment Boosters," with an additional half-segment to provide additional thrust at liftoff.

That final redesign would have made the Ares V booster taller and more powerful than the now-retired Saturn V/INT-20, [[N-1 rocket|N-1]], and [[Energia]] rockets, and would have allowed the Ares V to place both the [[Earth Departure Stage]] and [[Altair spacecraft]] into Low-Earth orbit for later on-orbit assembly. Unlike the 5-segment SRB for the Ares I, the 5.5-segment boosters for the Ares V were to be identical in design, construction, and function to the current SRBs except for the extra segments. Like the shuttle boosters, the Ares V boosters would fly an almost-identical flight trajectory from launch to splashdown.

The Constellation program, including Ares I and Ares V, was canceled in October 2010 by the passage of the 2010 NASA authorization bill.

===DIRECT===
The [[DIRECT]] proposal for a new, Shuttle-Derived Launch Vehicle, unlike the Ares I and Ares V boosters, uses a pair of classic 4-segment SRBs with the SSMEs used on the Shuttle.

===Athena III===
In 2008 [[PlanetSpace]] proposed the [[Athena (rocket family)#Athena III|Athena III]] launch vehicle for ISS resupply flights under the [[Commercial Orbital Transportation Services|COTS program]] – it would have featured 2 1/2 segments from the original SRB design.

===Space Launch System (SLS)===
[[File:Saturn_V-Shuttle-Ares_I-Ares_V-Ares_IV-SLS_Block_I&II.png|thumb|upright=1.35|Comparison of the Saturn V, Space Shuttle, Ares I, Ares V, Ares IV, SLS Block I and SLS Block II]]
{{main|Space Launch System}}
The first versions (Blocks 1 and 1B) of the [[Space Launch System]] (SLS) are planned to use a pair of [[#Five-segment booster|five-segment Solid Rocket Booster]]s (SRBs), which were developed from the four-segment SRBs used for the Shuttle. Modifications for the SLS included the addition of a center booster segment, new avionics, and new insulation which eliminates the Shuttle SRB's asbestos and is {{convert|1900|lb|kg|order=flip|abbr=on}} lighter. The five-segment SRBs provide approximately 25% more total impulse than the Shuttle SRB, and will not be recovered after use.<ref>{{cite web|last1=Priskos|first1=Alex|title=Five-segment Solid Rocket Motor Development Status|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120014501.pdf|website=ntrs.nasa.gov|publisher=NASA|accessdate=2015-03-11}}</ref><ref name="NSFHowToLaunch022012">{{cite web|url=http://www.nasaspaceflight.com/2012/02/sls-how-to-launch-nasas-new-monster-rocket/ |title=Space Launch System: How to launch NASA’s new monster rocket |publisher=NASASpaceFlight.com |date=20 February 2012 |accessdate=9 April 2012}}</ref>

==Labeled diagram==
[[File:Solid Rocket Boosters - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX HAER TX-116-K (sheet 2 of 3).tif|thumb|550px|left|Labeled diagram of SRB]]
{{clear}}

==See also==
* [[Solid rocket booster]]
* [[PEPCON disaster]]

==References==
{{Include-NASA}}
{{reflist}}

==External links==
{{Commons category|Space Shuttle Solid Rocket Boosters}}
* {{cite web | url = http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html | title = Solid Rocket Boosters | publisher = NASA}}
* [http://www.maniacworld.com/solid-rocket-booster.htm Solid Rocket Booster Separation] video
* [http://www.nasa.gov/mission_pages/shuttle/behindscenes/recovery_ships.html Liberty Star and Freedom Star bio page.]

{{Space Shuttle}}
{{Rocket engines}}
{{NASA space program}}

[[Category:Solid-fuel rockets]]
[[Category:Space Shuttle program]]
[[Category:NASA space launch vehicles]]

Space Shuttle Solid Rocket Booster

2018-09-18T15:49:22Z

Blastr42: /* Displays */

{{refimprove|date=February 2012}}
{{Infobox rocket stage
|name = Solid Rocket Booster
|image = Two Space Shuttle SRBs on the Crawler transporter.jpg
|caption =
|manufacturer = [[Thiokol]], later [[Alliant Techsystems|ATK]] United Space Boosters International, [[Pratt and Whitney]]
|country = United States
|rockets = [[Space Shuttle]]
|height = {{convert|149.16|ft|m|sp=us|abbr=on|order=flip}}
|alt-height =
|diameter = {{convert|12.17|ft|m|sp=us|abbr=on|order=flip}}
|alt-diameter =
|mass = {{convert|1300000|lb|kg|abbr=on|order=flip}}
|alt-mass =
|engines = off
|thrust = {{convert|2800000|lbf|kN|abbr=on|order=flip}}
|alt-thrust =
|time = 127 seconds
|fuel = [[Polybutadiene acrylonitrile|PBAN]]-[[Ammonium perchlorate composite propellant|APCP]]
}}

The '''Space Shuttle Solid Rocket Boosters''' ('''SRBs''') were the first [[solid fuel]] motors to be used for primary propulsion on a vehicle used for [[human spaceflight]]<ref>{{cite web | url = http://www.nasa.gov/returntoflight/system/system_SRB.html | title = NASA – Solid Rocket Boosters | publisher = NASA | archiveurl=https://web.archive.org/web/20130406193019/http://www.nasa.gov/returntoflight/system/system_SRB.html | archivedate = 2013-04-06}}</ref> and provided the majority of the [[Space Shuttle]]'s thrust during the first two minutes of flight. After burnout, they were jettisoned and parachuted into the Atlantic Ocean where they were [[recoverable booster|recovered]], examined, refurbished, and [[reusable launch system|reused]].

The SRBs were the most powerful solid rocket motors ever flown.<ref name="HaleAdministration2011">{{cite book|author1=Wayne Hale|author2=National Aeronautics and Space Administration|author3=Helen Lane |author4=Gail Chapline |author5=Kamlesh Lulla|title=Wings in Orbit: Scientific and Engineering Legacies of the Space Shuttle, 1971-2010|url=https://books.google.com/books?id=QczRqXWSWwMC&pg=PA5|date=7 April 2011|publisher=Government Printing Office|isbn=978-0-16-086847-4|pages=5}}</ref> Each provided a maximum {{convert|3100000|lbf|kN|abbr=on|order=flip|sigfig=3}} thrust, roughly double the most powerful single-[[combustion chamber]] [[liquid-propellant rocket]] engine ever flown, the [[Rocketdyne F-1]]. With a combined mass of about {{convert|1180000|kg|abbr=on}}, they comprised over half the mass of the Shuttle stack at liftoff. The motor segments of the SRBs were manufactured by [[Thiokol]] of [[Brigham City, Utah]], which was later purchased by [[Alliant Techsystems|ATK]]. The prime contractor for most other components of the SRBs, as well as for the integration of all the components and retrieval of the spent SRBs, was USBI, a subsidiary of [[Pratt and Whitney]]. This contract was subsequently transitioned to [[United Space Alliance]], a [[limited liability company]] joint venture of [[Boeing]] and [[Lockheed Martin]].

Out of 270 SRBs launched over the Shuttle program, all but four were recovered – those from [[STS-4]] (due to a parachute malfunction) and [[STS-51-L]] ([[Space Shuttle Challenger disaster|Challenger disaster]]).<ref>{{cite web|title=One year on – Review notes superb performance of STS-135’s SRBs|url=http://www.nasaspaceflight.com/2012/07/final-flight-superb-performance-sts-135s-srbs/|website=NASASpaceFlight.com|accessdate=February 26, 2015}}</ref> Over 5,000 parts were refurbished for reuse after each flight. The final set of SRBs that launched [[STS-135]] included parts that flew on 59 previous missions, including [[STS-1]].<ref>{{cite web|title=Booster stacking finished for final shuttle flight|url=http://www.spaceflightnow.com/shuttle/sts135/110418srbs/|website=Spaceflightnow.com|accessdate=February 26, 2015}}</ref> Recovery also allowed post-flight examination of the boosters,<ref>{{cite web|title=STS-134 IFA Review: SRBs and RSRMs Perform Admirably|url=http://www.nasaspaceflight.com/2011/06/sts-134-ifa-review-srbs-rsrms-perform-admirably/|website=NASASpaceFlight.com|accessdate=February 26, 2015}}</ref> identification of anomalies, and incremental design improvements.<ref name=RSRM-ALCS>{{cite web|title=Reusable Solid Rocket Motor—Accomplishments, Lessons, and a Culture of Success |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120001536.pdf |website=ntrs.nasa.gov |accessdate=February 26, 2015}}</ref>

==Overview==
[[File:Static Test Firing DM-2 for Solid Rocket Booster - GPN-2000-000053.jpg|thumb|Static test firing, 1978]]
[[File:STS-1 The Shuttle's Solid Rocket Boosters break away from Columbia's External Tank.jpg|thumb|right|210px|Solid Rocket Booster (SRB) separation]]
The two reusable SRBs provided the main thrust to lift the shuttle off the [[launch pad]] and up to an altitude of about {{convert|150000|ft|mi km|abbr=on}}. While on the pad, the two SRBs carried the entire weight of the external tank and [[Space Shuttle orbiter|orbiter]] and transmitted the weight load through their structure to the [[mobile launch platform]]. Each booster had a liftoff [[thrust]] of approximately {{convert|2800000|lbf|MN|lk=on}} at sea level, increasing shortly after liftoff to about {{convert|3100000|lbf|MN|abbr=on}}. They were ignited after the three [[Space Shuttle Main Engine]]s' thrust level was verified. Seventy-five seconds after SRB separation, SRB [[apogee]] occurred at an altitude of approximately {{convert|220000|ft|mi km|abbr=on}}; [[parachute]]s were then deployed and impact occurred in the ocean approximately {{convert|122|nmi|km|lk=on}} downrange, after which the two SRBs were recovered. The SRBs helped take the Space Shuttle to an altitude of 28 miles and a speed of 3,094 miles per hour along with the main engines.

The SRBs were the largest [[solid rocket|solid-propellant motors]] ever flown and the first of such large rockets designed for reuse. Each is {{convert|149.16|ft|m|abbr=on}} long and {{convert|12.17|ft|m|abbr=on}} in diameter.

The SRBs committed the shuttle to liftoff and ascent (to orbit) flight, without the possibility of launch or liftoff/ascent abort, until both motors had fully, and simultaneously, fulfilled their functions, consumed their propellants, were producing zero net reaction thrust and had been jettisoned (again simultaneously) by explosive jettisoning bolts from the remainder of the vehicle launch "stack" (shuttle w/engines; fuel/oxidizer tank). Only then could any conceivable set of launch or post-liftoff abort procedures be contemplated. In addition, failure of an individual SRB's thrust output or ability to adhere to the designed performance profile was not survivable.<ref> https://spaceflight.nasa.gov/outreach/SignificantIncidents/assets/rogers_commission_report.pdf</ref>

Each SRB weighed approximately {{convert|1300000|lb|kg|abbr=on}} at launch. The two SRBs constituted about 69% of the total lift-off mass. The [[propellant]] for each [[spacecraft propulsion|solid rocket motor]] weighed approximately {{convert|1100000|lb|kg|abbr=on}}. The inert weight of each SRB was approximately {{convert|200000|lb|kg}}.

Primary elements of each booster were the motor (including case, propellant, igniter, and [[rocket engine nozzle|nozzle]]), structure, separation systems, operational flight instrumentation, recovery avionics, [[pyrotechnics]], deceleration system, [[thrust vectoring|thrust vector]] control system, and [[range safety]] destruct system.

While the terms "solid rocket motor" and "solid rocket booster" are often used interchangeably, in technical use they have specific meanings. The term "solid rocket motor" applied to the propellant, case, igniter and nozzle. "Solid rocket booster" applied to the entire rocket assembly, which included the rocket motor as well as the recovery parachutes, electronic instrumentation, separation rockets, range safety destruct system, and thrust vector control.

Each booster was attached to the external tank at the SRB's aft frame by two lateral sway braces and a diagonal attachment. The forward end of each SRB was attached to the external tank at the forward end of the SRB's forward skirt. On the launch pad, each booster also was attached to the mobile launcher platform at the aft skirt by four [[frangible nut]]s that were severed at lift-off.

The boosters were composed of seven individually manufactured steel segments. These were assembled in pairs by the manufacturer, and then shipped to Kennedy Space Center by rail for final assembly. The segments were fixed together using circumferential tang, clevis, and [[clevis pin]] fastening, and sealed with [[O-ring]]s (originally two, changed to three after the [[Challenger Disaster|''Challenger'' Disaster]] in 1986) and heat-resistant putty.

==Components==
[[Image:Space Shuttle SRB diagram.png|500px|thumb|SRB Diagram]]

===Hold-down posts===
Each solid rocket booster had four hold-down posts that fit into corresponding support posts on the mobile launcher platform. Hold-down [[Screw|bolts]] held the SRB and launcher platform posts together. Each bolt had a nut at each end, the top one being a [[frangible nut]]. The top nut contained two [[NASA standard detonator]]s (NSDs), which were ignited at solid rocket motor ignition commands.

When the two NSDs were ignited at each hold down, the hold-down bolt traveled downward because of the release of tension in the bolt (pretensioned before launch), NSD gas pressure and gravity. The bolt was stopped by the stud deceleration stand, which contained sand. The SRB bolt was {{convert|28|in|mm|abbr=on}} long and {{convert|3.5|in|mm|abbr=on}} in diameter. The frangible nut was captured in a blast container.

The solid rocket motor ignition commands were issued by the orbiter's computers through the master events controllers to the hold-down pyrotechnic initiator controllers (PICs) on the [[mobile launcher platform]]. They provided the ignition to the hold-down NSDs. The launch processing system monitored the SRB hold-down PICs for low voltage during the last 16 seconds before launch. PIC low voltage would initiate a launch hold.

===Electrical power distribution===
Electrical power distribution in each SRB consisted of orbiter-supplied main [[Direct current|DC]] bus power to each SRB via SRB buses labeled A, B and C. Orbiter main DC buses A, B and C supplied main DC bus power to corresponding SRB buses A, B and C. In addition, orbiter main DC bus C supplied backup power to SRB buses A and B, and orbiter bus B supplied backup power to SRB bus C. This electrical power distribution arrangement allowed all SRB buses to remain powered in the event one orbiter main bus failed.

The nominal operating voltage was 28±4 volts DC.

===Hydraulic power units===
There were two self-contained, independent Hydraulic Power Units (HPUs) on each SRB. Each HPU consisted of an [[auxiliary power unit]] (APU), fuel supply module, [[hydraulic]] [[pump]], hydraulic reservoir and [[hydraulic fluid]] manifold assembly. The APUs were fueled by [[hydrazine]] and generated mechanical shaft power to drive a hydraulic pump that produced hydraulic pressure for the SRB hydraulic system. The two separate HPUs and two hydraulic systems were located on the aft end of each SRB between the SRB nozzle and aft skirt. The HPU components were mounted on the aft skirt between the rock and tilt actuators. The two systems operated from T minus 28 seconds until SRB separation from the orbiter and external tank. The two independent hydraulic systems were connected to the rock and tilt [[Servomechanism|servo]]actuators.

The HPU controller electronics were located in the SRB aft integrated electronic assemblies on the aft external tank attach rings.

The HPUs and their fuel systems were isolated from each other. Each fuel supply module (tank) contained {{convert|22|lb|kg|abbr=on}} of hydrazine. The fuel tank was pressurized with gaseous nitrogen at {{convert|400|psi|MPa|abbr=on|lk=on}}, which provided the force to expel (positive expulsion) the fuel from the tank to the fuel distribution line, maintaining a positive fuel supply to the APU throughout its operation.

In the APU, a fuel pump boosted the hydrazine pressure and fed it to a gas generator. The gas generator [[catalytic]]ally decomposed the hydrazine into hot, high-pressure gas; a two-stage turbine converted this into mechanical power, driving a gearbox. The waste gas, now cooler and at low pressure, was passed back over the gas generator housing to cool it before being dumped overboard. The gearbox drove the fuel pump, its own lubrication pump, and the HPU hydraulic pump. As described so far, the system could not self-start, since the fuel pump was driven by the turbine it supplied fuel to. Accordingly, a bypass line went around the pump and fed the gas generator using the nitrogen tank pressure until the APU speed was such that the fuel pump outlet pressure exceeded that of the bypass line, at which point all the fuel was supplied to the fuel pump.

When the APU speed reached 100%, the APU primary control valve closed, and the APU speed was controlled by the APU controller electronics. If the primary control valve logic failed to the open state, the secondary control valve assumed control of the APU at 112% speed.

Each HPU on an SRB was connected to both [[Servomechanism|servo]]actuators on that SRB by a switching valve that allowed the hydraulic power to be distributed from either HPU to both actuators if necessary. Each HPU served as the primary hydraulic source for one servoactuator, and a secondary source for the other servoactuator. Each HPU possessed the capacity to provide hydraulic power to both servoactuators within %115 operational limits in the event that hydraulic pressure from the other HPU should drop below {{convert|2050|psi|MPa|abbr=on}}. A switch contact on the switching valve closed when the valve was in the secondary position. When the valve was closed, a signal was sent to the APU controller, that inhibited the 100% APU speed control logic and enabled the 112% APU speed control logic. The 100-percent APU speed enabled one APU/HPU to supply sufficient operating hydraulic pressure to both servoactuators of that SRB.

The APU 100-percent speed corresponded to 72,000 rpm, 110% to 79,200 rpm, and 112% to 80,640 rpm.

The hydraulic pump speed was 3,600 rpm and supplied hydraulic pressure of {{convert|3050|+/-|50|psi|MPa|abbr=on}}. A high pressure [[relief valve]] provided overpressure protection to the hydraulic system and relieved at {{convert|3750|psi|MPa|abbr=on}}.

The APUs/HPUs and hydraulic systems were reusable for 20 missions.

===Thrust vector control===
{{further|thrust vectoring}}
Each SRB had two [[hydraulic]] [[gimbal]] servoactuators, to move the nozzle up/down and side-to-side. This provided [[thrust vectoring]] to help control the vehicle in all three axes (roll, pitch, and yaw).

The ascent thrust vector control portion of the flight control system directed the thrust of the three shuttle main engines and the two SRB nozzles to control shuttle attitude and trajectory during lift-off and ascent. Commands from the guidance system were transmitted to the ATVC (Ascent Thrust Vector Control) drivers, which transmitted signals proportional to the commands to each servoactuator of the main engines and SRBs. Four independent flight control system channels and four ATVC channels controlled six main engine and four SRB ATVC drivers, with each driver controlling one hydraulic port on each main and SRB servoactuator.

Each SRB servoactuator consisted of four independent, two-stage servovalves that received signals from the drivers. Each servovalve controlled one power spool in each actuator, which positioned an actuator ram and the nozzle to control the direction of thrust.

The four servovalves in each actuator provided a "force-summed majority voting" arrangement to position the power spool. With four identical commands to the four servovalves, the actuator force-sum action prevented a single erroneous command from affecting power ram motion. If the erroneous command persisted for more than a predetermined time, differential pressure sensing activated a selector valve to isolate and remove the defective servovalve hydraulic pressure, permitting the remaining channels and servovalves to control the actuator ram spool.

Failure monitors were provided for each channel to indicate which channel had been bypassed. An isolation valve on each channel provided the capability of resetting a failed or bypassed channel.

Each actuator ram was equipped with [[transducer]]s for position feedback to the thrust vector control system. Within each servoactuator ram was a splashdown load relief assembly to cushion the nozzle at water splashdown and prevent damage to the nozzle flexible bearing.

===Rate gyro assemblies===
Each SRB contained three [[Rate gyro]] assemblies (RGAs), with each RGA containing one pitch and one yaw gyro. These provided an output proportional to angular rates about the pitch and yaw axes to the orbiter computers and guidance, navigation and control system during first-stage ascent flight in conjunction with the orbiter roll rate gyros until SRB separation. At SRB separation, a switchover was made from the SRB RGAs to the orbiter RGAs.

The SRB RGA rates passed through the orbiter flight aft multiplexers/demultiplexers to the orbiter GPCs. The RGA rates were then mid-value-selected in redundancy management to provide SRB pitch and yaw rates to the user software. The RGAs were designed for 20 missions.

===Propellant===
[[File:STS-134 solid rocket booster segment stacking.jpg|thumb|left|Sections of the SRB filled with propellant being connected]]
The [[rocket propellant]] mixture in each solid rocket motor consisted of [[ammonium perchlorate]] ([[oxidizer]], 69.6% by weight), atomized [[aluminum]] powder ([[fuel]], 16%), [[iron oxide]] ([[catalyst]], 0.4%), [[Polybutadiene acrylonitrile|PBAN]] (binder, also acts as fuel, 12.04%), and an [[epoxy]] curing agent (1.96%).<ref name="sts-newsref-srb">{{cite web | url = http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html | title = Solid Rocket Boosters | website = NASA |access-date=June 28, 2016}}</ref><ref name="returntoflight-system-SRB">{{cite web | url = http://www.nasa.gov/returntoflight/system/system_SRB.html | title = Solid Rocket Boosters | website = NASA | access-date=June 28, 2016}}</ref> This propellant is commonly referred to as ''[[Ammonium Perchlorate Composite Propellant]]'', or simply APCP. This mixture gave the solid rocket motors a [[specific impulse]] of {{convert|242|isp}} at sea level or {{convert|268|isp}} in a vacuum.

The main fuel, aluminum, was used because it has a reasonable specific energy density of about 31.0 MJ/kg, but a high volumetric energy density, and is difficult to ignite accidentally.

The propellant had an 11-point [[star polygon|star]]-shaped perforation in the forward motor segment and a double-truncated-[[cone (geometry)|cone]] perforation in each of the aft segments and aft closure. This configuration provided high thrust at ignition and then reduced the thrust by approximately a third 50 seconds after lift-off to avoid [[Stress (mechanics)|overstressing]] the vehicle during [[Max Q|maximum dynamic pressure]] (Max Q).<ref name="sts-newsref-srb"/>

==Function==
[[Image:Srbthrust2.svg|right|400px|thumb|SRB Sea Level Thrust. Data from [[STS-107]]]]

===Ignition===
SRB ignition can occur only when a manual lock pin from each SRB safe and arm device has been removed. The ground crew removes the pin during prelaunch activities. At T minus five minutes, the SRB safe and arm device is rotated to the arm position. The solid rocket motor ignition commands are issued when the three [[Space Shuttle Main Engine]]s (SSMEs) are at or above 90-percent rated thrust, no SSME fail and/or SRB ignition [[Pyrotechnic]] Initiator Controller (PIC) low voltage is indicated and there are no holds from the Launch Processing System (LPS).

The solid rocket motor ignition commands are sent by the orbiter computers through the Master Events Controllers (MECs) to the safe and arm device [[NASA standard detonator|NASA standard detonators ("NSD"s)]] in each SRB. A PIC single-channel capacitor discharge device controls the firing of each pyrotechnic device. Three signals must be present simultaneously for the PIC to generate the pyro firing output. These signals — arm, fire 1 and fire 2 — originate in the [[IBM AP-101|orbiter general-purpose computers]] (GPCs) and are transmitted to the MECs. The MECs reformat them to 28 volt DC signals for the PICs. The arm signal charges the PIC capacitor to 40 volts DC (minimum of 20 volts DC).

The GPC launch sequence also controls certain critical main propulsion system valves and monitors the engine ready indications from the SSMEs. The MPS start commands are issued by the onboard computers at T minus 6.6 seconds (staggered start engine three, engine two, engine one all approximately within 0.25 of a second), and the sequence monitors the thrust buildup of each engine. All three SSMEs must reach the required 90% thrust within three seconds; otherwise, an orderly shutdown is commanded and safing functions are initiated.

Normal thrust buildup to the required 90% thrust level will result in the SSMEs being commanded to the lift off position at T minus three seconds as well as the fire 1 command being issued to arm the SRBs. At T minus three seconds, the vehicle base bending load modes are allowed to initialize (referred to as the "twang", movement of approximately {{convert|25.5|in|mm|abbr=on}} measured at the tip of the external tank, with movement towards the external tank).

The fire 2 commands cause the redundant NSDs to fire through a thin barrier seal down a flame tunnel. This ignites a pyro booster charge, which is retained in the safe and arm device behind a perforated plate. The booster charge ignites the propellant in the igniter initiator; and combustion products of this propellant ignite the solid rocket motor initiator, which fires down the entire vertical length of the solid rocket motor igniting the solid rocket motor propellant along its entire surface area instantaneously.

At T minus zero, the two SRBs are ignited, under command of the four onboard computers; separation of the four [[explosive bolts]] on each SRB is initiated; the two T-0 umbilicals (one on each side of the spacecraft) are retracted; the onboard master timing unit, event timer and mission event timers are started; the three SSMEs are at 100%; and the ground launch sequence is terminated.

===Lift-off and ascent===
Timing sequence referencing in ignition is critical for a successful liftoff and ascent flight. The explosive hold-down bolts relieve (through the launch support pedestals and pad structure) the asymmetric vehicle dynamic loads caused by the SSME ignition and thrust buildup, and applied thrust bearing loads. Without the hold-down bolts the SSMEs would violently tip the flight stack (orbiter, external tank, SRBs) over onto the external tank. That rotating moment is initially countered by the hold-bolts. Prior to release of the vehicle stack for liftoff, the SRBs must simultaneously ignite and pressurize their combustion chambers and exhaust nozzles to produce a thrust derived, net counter-rotating moment exactly equal to the SSME’s rotating moment. With the SRBs reaching full thrust, the hold-down bolts are blown, releasing the vehicle stack, the net rotating moment is zero, and the net vehicle thrust (opposing gravity) is positive, lifting the orbiter stack vertically from the launch pedestal, controllable through the coordinated [[gimbal]] movements of the SSMEs and the SRB exhaust nozzles.

During ascent, multiple all-axis accelerometers detect and report the vehicle's flight and orientation (referencing the flight deck aboard the orbiter), as the flight reference computers translate navigation commands (steering to a particular waypoint in space, and at a particular time) into engine and motor nozzle gimbal commands, which orient the vehicle about its center of mass. As the forces on the vehicle change due to propellant consumption, increasing speed, changes in aerodynamic drag, and other factors, the vehicle automatically adjusts its orientation in response to its dynamic control command inputs.

The net result is a relatively smooth and constant (then gradually decreasing) gravitational pull due to acceleration, coupled with a diminishing aerodynamic friction as the upper atmosphere is reached and surpassed.

===Separation===
The SRBs are jettisoned from the space shuttle at high altitude, about {{convert|146000|ft|km|abbr=on}}. SRB separation is initiated when the three solid rocket motor chamber pressure transducers are processed in the redundancy management middle value select and the head-end chamber pressure of both SRBs is less than or equal to {{convert|50|psi|kPa|abbr=on}}. A backup cue is the time elapsed from booster ignition.

The separation sequence is initiated, commanding the thrust vector control actuators to the null position and putting the main propulsion system into a second-stage configuration (0.8 second from sequence initialization), which ensures the thrust of each SRB is less than {{convert|100000|lbf|kN|abbr=on}}. Orbiter yaw attitude is held for four seconds, and SRB thrust drops to less than {{convert|60000|lbf|kN|abbr=on}}.

The SRBs separate from the external tank within 30 milliseconds of the ordnance firing command.

The forward attachment point consists of a ball (SRB) and socket (External Tank (ET)) held together by one bolt. The bolt contains one NSD pressure cartridge at each end. The forward attachment point also carries the range safety system cross-strap wiring connecting each SRB RSS and the ET RSS with each other.

The aft attachment points consist of three separate struts: upper, diagonal and lower. Each strut contains one bolt with an NSD pressure cartridge at each end. The upper strut also carries the umbilical interface between its SRB and the external tank and on to the orbiter.

There are four [[booster separation motor]]s on each end of each SRB. The BSMs separate the SRBs from the external tank. The solid rocket motors in each cluster of four are ignited by firing redundant NSD pressure cartridges into redundant confined detonating fuse manifolds.

The separation commands issued from the orbiter by the SRB separation sequence initiate the redundant NSD pressure cartridge in each bolt and ignite the BSMs to effect a clean separation.

===Range safety system===
A [[range safety]] system (RSS) provides for destruction of a rocket or part of it with on-board explosives by remote command if the rocket is out of control, in order to limit the danger to people on the ground from crashing pieces, explosions, fire, poisonous substances, etc. The RSS was only activated once – during the [[Space Shuttle Challenger disaster|Space Shuttle ''Challenger'' disaster]] (37 seconds after the breakup of the vehicle, when the SRBs were in uncontrolled flight).

The shuttle vehicle had two RSSs, one in each SRB. Both were capable of receiving two command messages (arm and fire) transmitted from the ground station. The RSS was used only when the shuttle vehicle violates a launch trajectory red line.

An RSS consists of two antenna couplers, command receivers/decoders, a dual distributor, a safe and arm device with two [[NASA standard detonator]]s (NSD), two confined detonating fuse manifolds (CDF), seven CDF assemblies and one linear-shaped charge (LSC).

The antenna couplers provide the proper impedance for radio frequency and ground support equipment commands. The command receivers are tuned to RSS command frequencies and provide the input signal to the distributors when an RSS command is sent. The command decoders use a code plug to prevent any command signal other than the proper command signal from getting into the distributors. The distributors contain the logic to supply valid destruct commands to the RSS pyrotechnics.

The NSDs provide the spark to ignite the CDF, which in turn ignites the LSC for booster destruction. The safe and arm device provides mechanical isolation between the NSDs and the CDF before launch and during the SRB separation sequence.

The first message, called arm, allows the onboard logic to enable a destruct and illuminates a light on the flight deck display and control panel at the commander and pilot station. The second message transmitted is the fire command.

The SRB distributors in the SRBs are cross-strapped together. Thus, if one SRB received an arm or destruct signal, the signal would also be sent to the other SRB.

Electrical power from the RSS battery in each SRB is routed to RSS system A. The recovery battery in each SRB is used to power RSS system B as well as the recovery system in the SRB. The SRB RSS is powered down during the separation sequence, and the SRB recovery system is powered up.
<ref>{{cite web|url=http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html#srb-safety |title=Solid Rocket Boosters |publisher=NASA |accessdate=2010-08-28 | archiveurl=https://web.archive.org/web/20100725220547/http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html | archivedate=2010-07-25}}</ref>

===Descent and recovery===
[[File:Srb splashdown.jpg|thumb|Splashdown of the right hand SRB from the launch of [[STS-124]].]]The SRBs are jettisoned from the shuttle system at 2 minutes and an altitude of about 146,000 feet (44 km). After continuing to rise to about 220,000 feet (67 km), the SRBs begin to fall back to earth and once back in the denser atmosphere are slowed by a parachute system to prevent damage on ocean impact. A command is sent from the orbiter to the SRB just before separation to apply battery power to the recovery logic network. A second, simultaneous command arms the three nose cap thrusters (for deploying the pilot and [[drogue parachute]]), the [[frustum]] ring detonator (for main parachute deployment), and the main parachute disconnect ordnance.

The recovery sequence begins with the operation of the high-altitude [[baroswitch]], which triggers the pyrotechnic nose cap thrusters. This ejects the nose cap, which deploys the [[pilot chute|pilot parachute]]. Nose cap separation occurs at a nominal altitude of {{convert|15704|ft|m|abbr=on}}, about 218 seconds after SRB separation. The {{convert|11.5|ft|m|abbr=on|adj=on}} diameter conical ribbon pilot parachute provides the force to pull lanyards attached to cut knives, which cut the loop securing the [[drogue parachute|drogue]] retention straps. This allows the pilot chute to pull the drogue pack from the SRB, causing the drogue suspension lines to deploy from their stored position. At full extension of the twelve {{convert|105|ft|m|abbr=on}} suspension lines, the drogue deployment bag is stripped away from the canopy, and the {{convert|54|ft|m|abbr=on|adj=on}} diameter conical ribbon drogue parachute inflates to its initial reefed condition. The drogue disreefs twice after specified time delays (using redundant 7 and 12-second reefing line cutters), and it reorients/stabilizes the SRB for main chute deployment. The drogue parachute has a design load of approximately {{convert|315000|lb|kg|abbr=on}} and weighs approximately {{convert|1200|lb|kg|abbr=on}}.

[[Image:STS-116 rocket boosters (NASA KSC-06PD-2794).jpg|thumb|The solid rocket boosters, jettisoned from the [[Space Shuttle Discovery|Space Shuttle ''Discovery'']] following the launch of [[STS-116]], floating in the Atlantic Ocean about 150 miles northeast of [[Cape Canaveral]]. On this occasion, the boosters landed several miles apart, but overnight winds and currents drifted them to the same location]]After the drogue chute has stabilized the SRB in a tail-first attitude, the frustum is separated from the forward skirt by a pyrotechnic charge triggered by the low-altitude baroswitch at a nominal altitude of {{convert|5500|ft|m|abbr=on}} about 243 seconds after SRB separation. The frustum is then pulled away from the SRB by the drogue chute. The main chute suspension lines are pulled out from deployment bags that remain in the frustum. At full extension of the lines, which are {{convert|203|ft|m|abbr=on}} long, the three main chutes are pulled from their deployment bags and inflate to their first reefed condition. The frustum and drogue parachute continue on a separate trajectory to splashdown. After specified time delays (using redundant 10 and 17-second reefing line cutters), the main chute reefing lines are cut and the chutes inflate to their second reefed and full open configurations. The main chute cluster decelerates the SRB to terminal conditions. Each of the {{convert|136|ft|m|abbr=on}} diameter, 20-degree conical ribbon parachutes have a design load of approximately {{convert|195000|lb|kg|abbr=on}} and each weighs approximately {{convert|2180|lb|kg|abbr=on}}. These parachutes are the largest that have ever been used — both in deployed size and load weight. The RSRM nozzle extension is severed by a pyrotechnic charge about 20 seconds after frustum separation.

Water impact occurs about 279 seconds after SRB separation at a nominal velocity of {{convert|76|ft/s|m/s}}. The water impact range is approximately {{convert|130|nmi|km|abbr=on}} off the eastern coast of [[Florida]]. Because the parachutes provide for a nozzle-first impact, air is trapped in the empty (burned out) motor casing, causing the booster to float with the forward end approximately {{convert|30|ft|m}} out of the water.

[[File:Freedom Star with SRB.JPG|thumb|Solid rocket booster of the [[STS-131]] mission being recovered and transported to Cape Canaveral by the {{MV|Freedom Star}}.]]

Formerly, the main chutes were released from the SRB at impact using a parachute release nut ordnance system (residual loads in the main chutes would deploy the parachute attach fittings with floats tethered to each fitting). The current design keeps the main chutes attached during water impact (initial impact and slapdown). Salt Water Activated Release (SWAR) devices are now incorporated into the main chute riser lines to simplify recovery efforts and reduce damage to the SRB.<ref>{{cite web | url=http://www.spaceflight.nasa.gov/shuttle/upgrades/swar.html | title= Salt Water Activated Release for the SRB Main Parachutes (SWAR) | date=2002-04-07 | publisher=NASA | archiveurl=https://web.archive.org/web/20020203162534/http://spaceflight.nasa.gov/shuttle/upgrades/swar.html | archivedate=2002-02-03}}</ref> The drogue deployment bag/pilot parachutes, drogue parachutes and frustums, each main chute, and the SRBs are buoyant and are recovered.

Specially fitted [[NASA recovery ship]]s, the {{MV|Freedom Star}} and the {{MV|Liberty Star}}, recover the SRBs and descent/recovery hardware. Once the boosters are located, the Diver Operated Plug (DOP) is maneuvered by divers into place to plug the SRB nozzle and drain the water from the motor case. Pumping air into and water out of the SRB causes the SRB to change from a nose-up floating position to a horizontal attitude more suitable for towing. The retrieval vessels then tow the boosters and other objects recovered back to [[Kennedy Space Center]].

==Challenger disaster==
{{Main|Space Shuttle Challenger disaster}}
[[Image:STS-51-L grey smoke on SRB.jpg|thumb|left|Camera captures grey smoke being emitted from the right-hand SRB on [[Space Shuttle Challenger|Space Shuttle ''Challenger'']] before the start of [[STS-51-L]].]]
The loss of Space Shuttle ''Challenger'' originated with a system failure of one of its SRBs. The cause of the accident was found by the [[Rogers Commission Report|Rogers Commission]] to be "a faulty design unacceptably sensitive to a number of factors" of the SRB joints compounded by unusually cold weather the morning of the flight.<ref>{{cite web | url=https://history.nasa.gov/rogersrep/v1ch4.htm | title=Report of the Presidential Commission on the Space Shuttle ''Challenger'' Accident, Chapter IV: The Cause of the Accident | publisher = NASA | archiveurl=https://web.archive.org/web/20130511035132/https://history.nasa.gov/rogersrep/v1ch4.htm |archivedate=2013-05-11 }}</ref><ref>{{cite web | url=http://choo.fis.utoronto.ca/mgt/DM.case.html | title= Space Shuttle Challenger Case}}</ref> The commission found that the large rubber "O-rings" in SRB joints were not effective at low temperatures like those of the January 1986 morning of the accident ({{convert|36|F|C|lk=off|sigfig=2}}). A cold-compromised joint in the right SRB failed at launch and eventually allowed hot gases from within that rocket booster to sear a hole into the adjacent main external fuel tank and also weaken the lower strut holding the SRB to the external tank. The leak in the SRB joint caused a catastrophic failure of the lower strut and partial detachment of the SRB, which led to a collision between the SRB and the external tank. With a disintegrating external tank and severely off-axis thrust from the right SRB, traveling at a speed of Mach 1.92 at {{convert|46,000|ft|km}}, the Space Shuttle stack disintegrated and was enveloped in an "explosive burn" (i.e. rapid [[deflagration]]) of the liquid propellants from the external tank.<ref name="history.nasa.gov">{{cite web | url=https://history.nasa.gov/rogersrep/v1ch3.htm | title=Report of the Presidential Commission on the Space Shuttle ''Challenger'' Accident, Chapter III: The Accident | publisher = NASA}}</ref> Concerns were briefed by the SRB manufacturer due to the cold temperatures, but were overridden due to resistance from NASA managers to change launch criteria at such a late stage in launch preparation.

During the subsequent downtime, detailed structural analyses were performed on critical structural elements of the SRB. Analyses were primarily focused in areas where anomalies had been noted during postflight inspection of recovered hardware.

One of the areas was the attachment ring where the SRBs are connected to the external tank. Areas of distress were noted in some of the fasteners where the ring attaches to the SRB motor case. This situation was attributed to the high loads encountered during water impact. To correct the situation and ensure higher strength margins during ascent, the attach ring was redesigned to encircle the motor case completely (360 degrees). Previously, the attachment ring formed a 'C' shape and encircled the motor case just 270 degrees.
[[File:Booster Rocket Breach - GPN-2000-001425.jpg|thumb|upright|The right SRB shows an anomalous plume at T+ 58.788 seconds. This plume would trigger the breakup of the vehicle 14 seconds later.]]
Additionally, special structural tests were performed on the aft skirt. During this test program, an anomaly occurred in a critical [[welding|weld]] between the hold-down post and skin of the skirt. A redesign was implemented to add reinforcement brackets and fittings in the aft ring of the skirt.

These two modifications added approximately {{convert|450|lb|kg|abbr=on}} to the weight of each SRB. The result is called a "Redesigned Solid Rocket Motor" (RSRM).<ref>{{cite web | url = http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_asm.html#srb_mods | title = Orbiter Manufacturing and Assembly | publisher = NASA}}</ref>

==Construction==
The prime contractor for the SRB motor segments was [[Thiokol|ATK Launch Systems]]' Wasatch Division based in [[Magna, Utah]].

United Space Boosters Inc. (USBI), a division of Pratt and Whitney, under United Technologies, was the original SRB prime contractor for SRB assembly, checkout and refurbishment for all non-solid-rocket-motor components and for SRB integration. They were the longest running prime contractor for the Space Shuttle that was part of the original launch team. USBI was absorbed by United Space Alliance as the Solid Rocket Booster Element division in 1998 and the USBI division was disbanded at Pratt & Whitney the following year. At its peak, USBI had over 1500 personnel working on the Shuttle Boosters at KSC, FL and Huntsville, AL.

Many other companies supplied various components for the SRBs:{{Citation needed|date=October 2012}}
* [[Parker-Abex Corp.]] of [[Kalamazoo, Michigan]] (hydraulic pumps)
* [[Aerojet]] of [[Redmond, Washington]] (hydrazine gas generators)
* [[Arde Inc.]] of [[Mahwah, New Jersey]] (hydrazine fuel supply modules)
* [[Arkwin Industries Inc.]] of [[Westbury, New York]] (hydraulic reservoirs)
* [[Aydin Vector Division]] of [[Newtown Township, Bucks County, Pennsylvania|Newtown, Pennsylvania]] (integrated electronic assemblies)
* [[Bendix Corp.]] of [[Teterboro, New Jersey]] (integrated electronic assemblies)
* [[Consolidated Controls Corp.]] of [[El Segundo, California]] (hydrazine)
* [[Eldec Corp.]] of [[Lynnwood, Washington]] (integrated electronic assemblies)
* [[Explosive Technology]] of [[Fairfield, California]] (CDF manifolds)
* [[Gaco Western]] of [[Seattle, Washington]] (Hypalon Paint)
* [[Lockheed Martin]] (formerly [[Martin Marietta]]) of [[Denver, Colorado]] (pyro initiator controllers)
* [[Moog Inc.]] of [[East Aurora, New York]] (servoactuators, fuel isolation valves)
* [[Motorola]] of [[Scottsdale, Arizona]] (range safety receivers)
* [[Pioneer Parachute Company]] of [[Manchester, Connecticut]] (parachutes)
* [[Sperry Rand Flight Systems]] of [[Phoenix, Arizona]] (multiplexers / demultiplexers)
* [[Teledyne]] of [[Lewisburg, Tennessee]] (location aid transmitters)
* [[ATK Launch Systems Corp.]] of [[Brigham City, Utah]] (separation motors)
* [[Hamilton Sundstrand]] of [[Windsor Locks, Connecticut]] (auxiliary power units)
* [[VACCO Industries]] of [[El Monte, California|South El Monte, California]] (safe and arm device)
* [[Voss Industries]] of [[Cleveland, Ohio]] (SRB Retention Bands)

==Advanced Solid Rocket Motor (ASRM) Project==
NASA was planning on replacing the post-''Challenger'' SRBs with a new Advanced Solid Rocket Motor (ASRM) to be built by [[Aerojet]]<ref>Leary, Warren E., [https://www.nytimes.com/1989/04/22/business/nasa-picks-lockheed-and-aerojet.html ''NASA Picks Lockheed and Aerojet''], New York Times, April 22, 1989</ref> at a new facility, designed by subcontractor, RUST International, on the location of a canceled [[Tennessee Valley Authority]] nuclear power plant, at Yellow Creek, Mississippi. The ASRM would have produced additional thrust in order to increase shuttle payload, so that it could carry modules and construction components to the ISS. The ASRM program was canceled in 1993 after robotic assembly systems and computers were on-site and approximately 2 billion dollars spent, in favor of continued use, after design flaw corrections, of the SRB.

==Filament-wound cases==
In order to provide the necessary performance to launch polar-orbiting shuttles from the [[SLC-6]] launch pad at [[Vandenberg Air Force Base]] in [[California]], SRBs using ''[[filament winding|filament-wound]] cases'' (FWC) were designed to be more lightweight than the steel cases used on Kennedy Space Center-launched SRBs.<ref name="ross">"[http://www.jsc.nasa.gov/history/oral_histories/RossJL/RossJL_1-26-04.pdf Jerry L. Ross]" NASA Johnson Space Center Oral History Project, 26 January 2004.</ref> Unlike the regular SRBs, which had the flawed field joint design that led to the ''Challenger'' Disaster in 1986, the FWC boosters had the "double tang" joint design (necessary to keep the boosters properly in alignment during the "twang" movement when the SSMEs are ignited prior to liftoff), but used the two O-ring seals. With the closure of SLC-6, the FWC boosters were scrapped by ATK and NASA, but their field joints, albeit modified to incorporate the current three O-ring seals and joint heaters, were later incorporated into the present-day field joints on the current SRBs.

==Five-segment booster==
Prior to the destruction of the [[Space Shuttle Columbia|Space Shuttle ''Columbia'']] in 2003, NASA investigated the replacement of the current 4-segment SRBs with either a 5-segment SRB design or replacing them altogether with liquid "flyback" boosters using either [[Atlas V]] or [[Delta IV]] EELV technologies. The 5-segment SRB, which would have required little change to the current shuttle infrastructure, would have allowed the space shuttle to carry an additional {{convert|20000|lbs|kg|abbr=on}} of payload in an [[International Space Station]]-inclination orbit, eliminate the dangerous [[Space Shuttle abort modes|"Return-to-Launch Site" (RTLS) and "Trans-Oceanic Abort]]" (TAL) modes, and, by using a so-called "dog-leg maneuver", fly south-to-north polar orbiting flights from Kennedy Space Center. After the destruction of ''Columbia'', NASA shelved the five-segment SRB for the Shuttle Program, and the three surviving Orbiters, [[Space Shuttle Discovery|''Discovery'']], [[Space Shuttle Atlantis|''Atlantis'']], and [[Space Shuttle Endeavour|''Endeavour'']] were retired in 2011 after the completion of the [[International Space Station]].<ref>Jenkins, Dennis R. "Space Shuttle: History of the National Space Transportation System – The First 100 Flights"</ref> One five-segment engineering test motor, ETM-03, was fired on October 23, 2003.<ref>{{cite web |url=http://www.csar.illinois.edu/F_viz/gallery/AIAA/RSRMV/McMillinETM-03-AIAA-2004-3895.pdf |title=A Review of ETM-03 (A Five Segment Shuttle RSRM Configuration) Ballistic Performance |author=J. E. McMillin and J. A. Furfaro |deadurl=yes |archiveurl=https://web.archive.org/web/20110719211113/http://www.csar.illinois.edu/F_viz/gallery/AIAA/RSRMV/McMillinETM-03-AIAA-2004-3895.pdf |archivedate=2011-07-19 |df= }}</ref><ref>{{cite web |url=http://www.nasa.gov/centers/marshall/news/news/releases/2003/03-186.html |title=Most powerful Space Shuttle Solid Rocket Motor ever tested proves it can be pushed close to edge, yet still perform flawlessly |publisher=NASA MSFC}}</ref>

As part of the Constellation Program, the first stage of the [[Ares I]] rocket was planned to use five-segment SRBs – in September 2009 a five-segment Space Shuttle SRB was static fired on the ground in ATK's desert testing area in Utah.<ref name="NASA">{{cite web|url=http://www.nasa.gov/mission_pages/constellation/ares/dm1_success.html |title=NASA and ATK Successfully Test Ares First Stage Motor |publisher=NASA |accessdate=2010-03-25 | archiveurl=https://web.archive.org/web/20100325103340/http://www.nasa.gov/mission_pages/constellation/ares/dm1_success.html | archivedate=2010-03-25}}</ref>

After the Constellation Program was cancelled in 2011, the new [[Space Launch System]] (SLS) was designated to use five-segment boosters. The first test of a SRB for SLS was completed in early 2015, a second test was performed in mid 2016 at Orbital ATK's Promontory, Utah facility.<ref>{{cite web|url=https://www.orbitalatk.com/news-room/release.asp?prid=147|title=News Room|author=|date=|website=www.orbitalatk.com|accessdate=4 April 2018}}</ref>

==Displays==
Space Shuttle Solid Rocket Boosters are on display at the [[Kennedy Space Center Visitors Complex]] in Florida, the [[Stennis Space Center]] in Hancock County, Mississippi, the [[United States Space & Rocket Center]] in Huntsville, Alabama, and at [[Orbital ATK]]'s facility near [[Promontory, Utah]].<ref>{{cite web|title=Launch Vehicles|url=http://web.mac.com/jimgerard/AFGAS/pages/booster/index.html|work=A Field Guide to American Spacecraft|deadurl=yes|archiveurl=https://web.archive.org/web/20100312030139/http://web.mac.com/jimgerard/AFGAS/pages/booster/index.html|archivedate=2010-03-12|df=}}</ref>
A partial filament-wound booster case is on display [[Pima Air & Space Museum]] in [[Tucson, Arizona]].<ref>{{cite web|title=“Space shuttle solid rocket booster arrives for display at Arizona museum|url=http://www.collectspace.com/news/news-122916a-pima-air-space-museum-rocket-booster.html|website=Pima Air & Space Museum|publisher=|accessdate=September 18, 2018}}</ref>

==Future and proposed uses==
[[Image:Ares I-X launch 08.jpg|thumb|The Ares I-X prototype launches from LC-39B, 15:30 UTC, October 28, 2009 – this was as of 2016 the sole flight of a launch vehicle [[wikt:derived|derived]] from the SRB.]]
Over time several proposals to reuse the SRB design were presented – however, as of 2016 none of these proposals progressed to regular flights before being cancelled. Until the [[Exploration Mission 1|2019 planned first flight]] of the [[Space Launch System]] (SLS), a sole test-flight of the [[Ares I-X]] prototype in 2009 was the furthest any of these proposals progressed.

===Ares===
NASA initially planned to reuse the four-segment SRB design and infrastructure in several Ares rockets, which would have propelled the Orion spacecraft into orbit. In 2005, NASA announced the [[Shuttle-Derived Launch Vehicle]] slated to carry the [[Orion spacecraft|Orion]] Crew Exploration Vehicle into low-Earth orbit and later to the Moon. The SRB-derived Crew Launch Vehicle (CLV), named [[Ares I]], was planned to feature a single modified four-segment SRB for its first stage; a single liquid-fueled modified [[Space Shuttle Main Engine]] would have powered the second stage.

The Ares I design updated in 2006 featured one five-segment SRB (originally developed for the Shuttle, but never used) as a first stage – the second stage was powered by an uprated [[J-2 (rocket engine)|J-2X]] engine, derived from the [[Rocketdyne J-2|J-2]], which had been used in the upper stage of [[Saturn V]] and [[Saturn IB]]. In place of the standard SRB nosecone, the Ares I would have a tapered interstage assembly connecting the booster proper with the second stage, an attitude control system derived from the [[Regulus missile]] system, and larger, heavier parachutes to lower the stage into the Atlantic Ocean for recovery.

Also introduced in 2005, was a [[Heavy Lift Launch Vehicle|heavy-lift]] Cargo Launch Vehicle (CaLV) named [[Ares V]]. Early designs of the Ares V utilized ''five'' standard-production SSMEs and a pair of 5-segment boosters identical to those proposed for the Shuttle, while later plans redesigned the boosters around the [[RS-68]] rocket engine used on the Delta IV EELV system. Initially, NASA switched over to a system using the 5-segment boosters and a cluster of five RS-68s (which resulted in a widening of the Ares V core unit), then NASA reconfigured the vehicle with six RS-68B engines, with the boosters themselves becoming "5.5-Segment Boosters," with an additional half-segment to provide additional thrust at liftoff.

That final redesign would have made the Ares V booster taller and more powerful than the now-retired Saturn V/INT-20, [[N-1 rocket|N-1]], and [[Energia]] rockets, and would have allowed the Ares V to place both the [[Earth Departure Stage]] and [[Altair spacecraft]] into Low-Earth orbit for later on-orbit assembly. Unlike the 5-segment SRB for the Ares I, the 5.5-segment boosters for the Ares V were to be identical in design, construction, and function to the current SRBs except for the extra segments. Like the shuttle boosters, the Ares V boosters would fly an almost-identical flight trajectory from launch to splashdown.

The Constellation program, including Ares I and Ares V, was canceled in October 2010 by the passage of the 2010 NASA authorization bill.

===DIRECT===
The [[DIRECT]] proposal for a new, Shuttle-Derived Launch Vehicle, unlike the Ares I and Ares V boosters, uses a pair of classic 4-segment SRBs with the SSMEs used on the Shuttle.

===Athena III===
In 2008 [[PlanetSpace]] proposed the [[Athena (rocket family)#Athena III|Athena III]] launch vehicle for ISS resupply flights under the [[Commercial Orbital Transportation Services|COTS program]] – it would have featured 2 1/2 segments from the original SRB design.

===Space Launch System (SLS)===
[[File:Saturn_V-Shuttle-Ares_I-Ares_V-Ares_IV-SLS_Block_I&II.png|thumb|upright=1.35|Comparison of the Saturn V, Space Shuttle, Ares I, Ares V, Ares IV, SLS Block I and SLS Block II]]
{{main|Space Launch System}}
The first versions (Blocks 1 and 1B) of the [[Space Launch System]] (SLS) are planned to use a pair of [[#Five-segment booster|five-segment Solid Rocket Booster]]s (SRBs), which were developed from the four-segment SRBs used for the Shuttle. Modifications for the SLS included the addition of a center booster segment, new avionics, and new insulation which eliminates the Shuttle SRB's asbestos and is {{convert|1900|lb|kg|order=flip|abbr=on}} lighter. The five-segment SRBs provide approximately 25% more total impulse than the Shuttle SRB, and will not be recovered after use.<ref>{{cite web|last1=Priskos|first1=Alex|title=Five-segment Solid Rocket Motor Development Status|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120014501.pdf|website=ntrs.nasa.gov|publisher=NASA|accessdate=2015-03-11}}</ref><ref name="NSFHowToLaunch022012">{{cite web|url=http://www.nasaspaceflight.com/2012/02/sls-how-to-launch-nasas-new-monster-rocket/ |title=Space Launch System: How to launch NASA’s new monster rocket |publisher=NASASpaceFlight.com |date=20 February 2012 |accessdate=9 April 2012}}</ref>

==Labeled diagram==
[[File:Solid Rocket Boosters - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX HAER TX-116-K (sheet 2 of 3).tif|thumb|550px|left|Labeled diagram of SRB]]
{{clear}}

==See also==
* [[Solid rocket booster]]
* [[PEPCON disaster]]

==References==
{{Include-NASA}}
{{reflist}}

==External links==
{{Commons category|Space Shuttle Solid Rocket Boosters}}
* {{cite web | url = http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html | title = Solid Rocket Boosters | publisher = NASA}}
* [http://www.maniacworld.com/solid-rocket-booster.htm Solid Rocket Booster Separation] video
* [http://www.nasa.gov/mission_pages/shuttle/behindscenes/recovery_ships.html Liberty Star and Freedom Star bio page.]

{{Space Shuttle}}
{{Rocket engines}}
{{NASA space program}}

[[Category:Solid-fuel rockets]]
[[Category:Space Shuttle program]]
[[Category:NASA space launch vehicles]]

Vulcan Centaur

2018-07-28T19:53:17Z

Blastr42: XCOR is defunct now.

{{hatnote|This article is about the proposed American Vulcan launch vehicle. Not to be confused with the Russian [[Vulkan-Hercules]] concept launch vehicle or the European [[Vulcain]] rocket engine. For other uses, see [[Vulcan (disambiguation)|Vulcan]].}}
{{Infobox rocket
|name = Vulcan
|image = ULA_Vulcan.png
|caption = A simulated expanded view of the 561-configuration Vulcan rocket.
|function = Partly-reusable [[launch vehicle]]
|manufacturer = [[United Launch Alliance|ULA]]
|country-origin = United States
|height = 
|diameter = {{convert|5.4|m|ft|abbr=on}}<ref>{{cite web|last1=Peller|first1=Mark|title=United Launch Alliance|url=http://www.ispcs.com/content/files/Mark%20Peller.pdf|accessdate=2016-03-30|archive-url=https://web.archive.org/web/20160412062627/http://www.ispcs.com/content/files/Mark%20Peller.pdf|archive-date=2016-04-12|dead-url=yes|df=}}</ref>
|mass = 
|stages = 2

|capacities =
{{Infobox rocket/payload
|location = [[Low Earth Orbit|LEO]]
|kilos = {{cvt|78000|lb|order=flip}}<ref name=ToryBruno201804>{{cite tweet |user=torybruno |number=987473611672858624 |title=Vulcan is coming |date=20 April 2018}}</ref>(Vulcan Heavy [[Centaur V|Centaur]])}}

{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = {{cvt|35000|lb|order=flip}}<ref name=ToryBruno201804 />(Vulcan Heavy [[Centaur V|Centaur]])}}

{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = {{cvt|15000|lb|order=flip}}<ref name=ToryBruno201804 />(Vulcan Heavy [[Centaur V|Centaur]])}}
|comparable = {{flatlist|
* [[Ariane 5]]
* [[Delta IV Heavy]]
* [[Falcon Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
}}
|status = In development
|sites = [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 41|SLC-41]] [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 3|SLC-3E]]<ref name="sn20151012">{{cite news |last1=Clark|first1=Stephen |title=ULA selects launch pads for new Vulcan rocket |url=http://spaceflightnow.com/2015/10/12/ula-selects-launch-pads-for-new-vulcan-rocket/ |accessdate=12 October 2015 |work=Spaceflight Now |date=12 October 2015}}</ref>
|launches =
|success =
|fail =
|partial =
|first= Mid-2020 (planned)
|last=
|stagedata = 
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name =
|number = 0–6
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = GEM 63XL<ref>{{cite web|last1=Rhian|first1=Jason|title=ULA selects Orbital ATK's GEM 63/63XL SRBs for Atlas V and Vulcan Boosters|url=http://www.spaceflightinsider.com/organizations/ula/ula-selects-orbital-atks-gem-6363-xl-srbs-for-atlas-v-and-vulcan-boosters/|website=Spaceflight Insider|accessdate=2015-09-25}}</ref>
|solid = yes
|thrust = 
|total = 
|SI = 
|burntime = 
|fuel = [[HTPB]]
}}
{{Infobox rocket/stage
|type = stage
|diff = 
|stageno = First
|name = 
|number = 
|length = 
|diameter = {{convert|5.4|m|abbr=on}} (BE-4 option), or {{convert|3.81|m|abbr=on}} (AR1 option)
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 2× [[BE-4]] or [[AR1 (rocket engine)|AR1]]
|solid = 
|thrust = {{convert|1100000|lb-f|kN|order=flip|lk=in|abbr=on}}
|total = 
|SI = 
|burntime = 
|fuel = [[Liquid methane|CH4]] or [[RP-1]] / [[Liquid oxygen|LOx]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name = [[Centaur (rocket stage)|Centaur]] (initial flights, late-2010s)
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 4× [[RL10]]-C<ref>{{cite web|title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine for Next-generation Vulcan Centaur Upper Stage|url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage|website=United Launch Alliance website|accessdate=11 May 2018}}</ref>
|solid = 
|thrust = {{convert|415.2|kN|lb-f|lk=in|abbr=on}}{{citation needed|date=February 2018}}
|total = 
|SI = {{convert|448.5|isp}}
|burntime = 
|fuel = [[Liquid hydrogen|LH2]] / [[Liquid oxygen|LOX]]
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name = [[Advanced Cryogenic Evolved Stage|ACES]] (proposed, mid-2020s)
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 4× [[RL10]]-C or 1× [[BE-3]] engine (TBC)
|solid = 
|thrust = 
|total = 
|SI = 
|burntime = 
|fuel = [[Liquid hydrogen|LH2]] / [[Liquid oxygen|LOx]]
}}
}}

The '''''Vulcan''''' rocket, also known as the '''''Vulcan Centaur''''',<ref name=sn20180325/> is an American heavy-payload [[launch vehicle]] under [[new product development|development]] since 2014 by [[United Launch Alliance]] (ULA), funded by a [[public–private partnership]] with the [[Federal government of the United States|US government]]. ULA expects the [[maiden flight|first launch]] of the new rocket to occur no earlier than mid-2020.<ref name=SpaceNewsFoust201801>{{cite tweet |user=jeff_foust |number=954054070821670912 |title=Tom Tshudy, ULA: with Vulcan we plan to maintain reliability and on-time performance of our existing rockets, but at a very affordable price. First launch mid-2020. |date=18 January 2018}}</ref>

Through the first several years of the development project, the ULA board of directors had made only short-term (quarterly) funding commitments to the rocket program, and it remains unclear if long-term private funding will be available to finish the project. {{As of|2016|3}}, the US government had committed {{USD|201 million}} to Vulcan development.<ref name=sn20160310/> {{As of|2018|3}}, Tory Bruno noted that Vulcan Centaur is 75 percent privately funded.<ref name=dd20160412/><ref>{{cite web |url=http://spacenews.com/air-force-stakes-future-on-privately-funded-launch-vehicles-will-the-gamble-pay-off/ |title=Air Force stakes future on privately funded launch vehicles. Will the gamble pay off? |first1=Sandra |last1=Erwin |publisher=Space News |date=25 March 2018}}</ref>

== History ==
ULA had considered several launch vehicle concepts in the decade since the company was formed in 2006. Various concepts for derivative vehicles based on the [[Atlas (rocket)|Atlas]] and [[Delta (rocket)|Delta]] lines of launch vehicles they inherited from their predecessor companies were presented to the US government for funding. None were funded beyond concept stage.

In early 2014, geopolitical and [[Federal government of the United States|US]] political considerations involving [[international sanctions during the Ukrainian crisis]], led to an effort by ULA to consider possibly replacing the Russian-supplied [[RD-180]] engine used on the first stage booster of the Atlas V. Formal study contracts were issued by ULA in June 2014 to several US rocket engine suppliers.<ref name="sn20140917" /> ULA was also facing competition from [[SpaceX]], then seen to affect ULA's core national security market of US military launches, and by July 2014 the [[United States Congress]] was debating whether to legislate a ban on future use of the RD-180.<ref name="sn20150424">{{cite news |last1=Gruss|first1=Mike |title=Evolution of a Plan : ULA Execs Spell Out Logic Behind Vulcan Design Choices |url=http://spacenews.com/evolution-of-a-plan-ula-execs-spell-out-logic-behind-vulcan-design-choices/ |work=Space News |date=2015-04-24 |accessdate=25 April 2015}}</ref>

=== New first stage booster ===
In September 2014, ULA announced that it had entered into a partnership with [[Blue Origin]] to develop the [[BE-4]] [[liquid oxygen]] (LOX) and [[liquid methane]] (CH4) engine to replace the RD-180 on a new first stage [[Booster (rocketry)|booster]]. The Blue engine was already in its third year of development by Blue Origin, and ULA said it expected the new stage and engine to start flying no earlier than 2019.<ref name="dd20150207" /> Two of the {{convert|550000|lbf|kN|order=flip|adj=on|lk=on}}-thrust BE-4 engines were to be used on a new launch vehicle booster.<ref name="sn20140917">{{cite news |last1=Ferster|first1=Warren |title=ULA To Invest in Blue Origin Engine as RD-180 Replacement |url=http://www.spacenews.com/article/launch-report/41901ula-to-invest-in-blue-origin-engine-as-rd-180-replacement |date=2014-09-17 |work=Space News |access-date=2014-09-19}}</ref> ULA referred to the successor concept vehicle as a "next generation launch system"<ref name="dbj20141016" /> and used that descriptor into early 2015.<ref name="dd20150207">{{cite news |last1=Fleischauer|first1=Eric |title=ULA’s CEO talks challenges, engine plant plans for Decatur |url=http://www.decaturdaily.com/news/ula-s-ceo-talks-challenges-engine-plant-plans-for-decatur/article_8ba49046-af4a-11e4-97ef-ff58591d43fc.html |work=Decatur Daily |date=7 February 2015 |accessdate=2015-04-17}}</ref>

In October 2014, ULA announced a major restructuring of company processes and workforce to reduce launch costs by half. One of the reasons given for the restructuring and new cost reduction goals was [[Space launch market competition|new competition in the launch market]] from SpaceX.<ref name="dbj20141016" /><ref name="sn20150424" /> ULA planned to have preliminary design ideas in place for a blending of its existing [[Atlas V]] and [[Delta IV]] technologies by the end of 2014, to build a successor to the Atlas V that would allow the company to halve Atlas V launch costs.<ref name="dbj20141016">{{cite news |last1=Avery|first1=Greg |title=ULA plans new rocket, restructuring to cut launch costs in half |url=http://www.bizjournals.com/denver/blog/boosters_bits/2014/10/exclusive-ula-plans-a-new-rocket-restructuring-to.html |accessdate=2015-04-17 |work=Denver Business Journal |date=2014-10-16}}</ref> A part of the restructuring effort was described as the effort to co-develop the alternative BE-4 engine with Blue Origin for the new launch vehicle.<ref name="spo20141114">{{cite news |last1=Delgado|first1=Laura M. |title=ULA's Tory Bruno Vows To Transform Company |url=http://www.spacepolicyonline.com/news/ulas-tory-bruno-vows-to-transform-company |accessdate=2015-04-17 |work=SpacePolicyOnline.com |date=2014-11-14}}</ref>

=== Unveiling ===
On 13 April 2015, CEO [[Tory Bruno]] unveiled the new ULA launch vehicle as the ''Vulcan'' at the 31st [[Space Symposium]], a new [[two-stage-to-orbit]] (TSTO) rocket that would be rolled out incrementally. The ''Vulcan'' name was chosen after an online poll to select the name. [[Vulcan Inc.]] stated that it held the trademark on the name and contacted ULA.<ref name="nbc20150413">{{cite news |last1=Boyle |first1=Alan |url=http://www.nbcnews.com/science/space/united-launch-alliance-boldly-names-its-next-big-rocket-vulcan-n340881 |work=NBC |title=United Launch Alliance Boldly Names Its Next Rocket: Vulcan! |date=2015-04-13 |accessdate=2015-04-17}}</ref>{{update after|2018|5|13}} ULA stated its goal was to sell a "barebones Vulcan" for half the [[price]] of a basic Atlas V rocket, which sold for about $164 million {{asof|2015|lc=y}}. Addition of strap-on boosters for heavier satellites would increase the price.<ref name="sfn-20150422">{{cite news |url=http://spaceflightnow.com/2015/04/22/ula-needs-commercial-business-to-close-vulcan-rocket-business-case/ |title=ULA needs commercial business to close Vulcan rocket business case |first1=Stephen |last1=Clark |work=Spaceflight Now |date=22 April 2015 |accessdate=23 April 2015}}</ref> At the announcement, the ULA [[Board of directors|board]] had not yet approved the new launch vehicle, with first launch planned in 2019.<ref name="sn20150424" />

ULA put forth an "incremental approach" to rolling out the vehicle and its technologies,<ref name="sn20150413">{{cite news |last1=Gruss |first1=Mike |url=http://spacenews.com/ulas-vulcan-rocket-to-be-rolled-out-in-stages/ |work=SpaceNews |title=ULA’s Vulcan Rocket To be Rolled out in Stages |date=2015-04-13 |accessdate=2015-04-17}}</ref> with Vulcan deployment beginning with the first stage, based on the Delta IV's fuselage diameter and production process, expected to use two BE-4 engines. The [[Aerojet Rocketdyne#AR1|Aerojet Rocketdyne AR1 engine]] was retained by ULA as a contingency option, with a final decision projected to be made in 2016.{{update after|2017}} The first stage will be able to optionally use from one to six [[solid rocket booster]]s (SRBs) for added liftoff thrust,<ref name=Apr2015>[http://www.ulalaunch.com/ula-unveils-americas-new-rocket-vulcan.aspx?title=United+Launch+Alliance+Unveils+America%E2%80%99s+New+Rocket+%E2%80%93+Vulcan%3a+Innovative+Next+Generation+Launch+System+will+Provide+Country%E2%80%99s+Most+Reliable%2c+Affordable+and+Accessible+Launch+Service United Launch Alliance Unveils America’s New Rocket – Vulcan: Innovative Next Generation Launch System will Provide Country’s Most Reliable, Affordable and Accessible Launch Service. April 2015]</ref> launch a heavier payload than the highest-rated Atlas V in the six-SRB configuration.

ULA announced a feature they could subsequently develop which would make the first stage partly reusable: allowing the engines to detach from the vehicle after [[main engine cutoff]], descend through the [[atmospheric reentry|atmosphere]] with a heat shield and parachute, being captured by a helicopter in mid-air.<ref name="nbc20150413" /> ULA estimated that reusing the engines in this way would reduce the cost of the first stage propulsion by 90%, where propulsion is 65% of the total first stage cost.<ref name="sfn20150414">{{cite news |last1=Ray|first1=Justin |url=http://spaceflightnow.com/2015/04/14/ula-chief-explains-reusability-and-innovation-of-new-rocket/ |title=ULA chief explains reusability and innovation of new rocket |work=Spaceflight Now |date=14 April 2015 |accessdate=2015-04-17}}</ref> Initial configurations of Vulcan were intended then to use the same [[Centaur (rocket stage)|Centaur upper stage]] as the Atlas V, with its existing [[RL10]] engines, while a later advanced cryogenic upper stage — called the ''[[Advanced Cryogenic Evolved Stage]]'' (ACES) — was conceptually planned for full development by ULA in the late 2010s. ACES would be LOX and [[liquid hydrogen]] (LH2) powered by one to four rocket engines yet to be selected, and would include the [[Integrated Vehicle Fluids]] technology that could allow much longer on-orbit life of the upper stage, measured in weeks rather than hours.<ref name="dp20150413">{{cite web |url=http://www.denverpost.com/business/ci_27905093/america-meet-vulcan-your-next-united-launch-alliance |title=America, meet Vulcan, your next United Launch Alliance rocket |work=Denver Post |date=2015-04-13 |accessdate=2015-04-17}}</ref><ref name="sn20150413" />

{{Anchor|Vulcan Heavy}}In May 2015, ULA released a chart showing a potential future Vulcan Heavy three-core launch vehicle concept with {{cvt|50000|lb|order=flip|adj=on}}-payload capacity to [[geostationary transfer orbit]], while a single-core Vulcan 561 with the ACES upper stage would have {{cvt|33200|lb|order=flip|adj=on}} capacity to the same orbit.<ref name="ula20150505">{{cite tweet |author=Tory Bruno |author-link=Tory Bruno |user=torybruno |number=595628488410963970 |title=ULA Full Spectrum Lift Capability |date=5 May 2015 |access-date=8 May 2015}}</ref>

In September 2015, ULA and Blue Origin announced an agreement to expand production capabilities to include the [[BE-4]] rocket engine then in development and test. However, ULA also reconfirmed that the decision on the BE-4 versus the AJR AR1 would not be made until late 2016, with maiden flight of Vulcan no earlier than 2019.<ref name="wsj20150910">{{cite news |url=https://www.wsj.com/articles/boeing-lockheed-differ-on-whether-to-sell-rocket-joint-venture-1441933638 |title=Boeing, Lockheed Differ on Whether to Sell Rocket Joint Venture |work=Wall Street Journal |date=10 September 2015 |accessdate=2015-09-12}}</ref>

=== Engine testing and design optimization ===
{{As of|2016|01}}, full-engine testing of the BE-4 was planned to begin prior to the end of 2016,<ref name="sn20160123b">{{cite news |last=Berger|first=Brian |url=http://spacenews.com/launch-land-repeat-blue-origin-posts-video-of-new-shepards-friday-flight/ |title=Launch. Land. Repeat: Blue Origin posts video of New Shepard’s Friday flight |work=SpaceNews |date=2016-01-23 |accessdate=2016-01-24 |quote=''Also this year, we’ll start full-engine testing of the BE-4''}}</ref>{{update after|2017}} while ULA was designing two versions of the Vulcan first stage, one using the BE-4 with a {{convert|5.4|m|ft|sp=us|abbr=on|adj=on}} outer diameter to support the less-dense [[liquid methane|methane]] fuel and an AR1 design with the same {{convert|3.81|m|ft|sp=us|abbr=on|adj=on}} diameter as Atlas V for the denser [[RP-1]] (kerosene) fuel.<ref name=sn20160316>{{cite news |last=de Selding|first=Peter B. |url=http://spacenews.com/ula-intends-to-lower-its-costs-and-raise-its-cool-to-compete-with-spacex/ |title=ULA intends to lower its costs, and raise its cool, to compete with SpaceX |work=[[SpaceNews]] |date=2016-03-16 |accessdate=2016-03-19 |quote=Methane rocket has a lower density so we have a 5.4 meter design outside diameter, while drop back to the Atlas V size for the kerosene AR1 version. ... Aerojet Rocketdyne AR1 ... haven't built any hardware yet ... additive manufacturing is revolutionizing complex casting ... Aerojet is investing a little bit of their own money. Primarily they are counting on the government's RPS (Rocket Propulsion System) contracts to drive the funding.}}</ref>

ULA completed the [[Preliminary Design Review]] (PDR) in March 2016 for one of the two parallel designs: the Vulcan/Centaur launch vehicle with dual Blue Origin BE-4 engines. The PDR "confirms that the design meets the requirements for the diverse set of missions it will support."<ref name=ula20160324>{{cite web |url=http://www.ulalaunch.com/ula-completes-Vulcan-Centaur-PDR.aspx |title=United Launch Alliance Completes Preliminary Design Review for Next-Generation Vulcan Centaur Rocket |deadurl=no |archiveurl= https://web.archive.org/web/20160325145546/http://www.ulalaunch.com/ula-completes-Vulcan-Centaur-PDR.aspx |archivedate=2016-03-25 |accessdate=2016-03-25}}</ref> In the event, BE-4 engine testing did not begin until 2017.<ref name=ars20171019/>

In April 2016, ULA CEO Tory Bruno stated that the company was targeting a complete launch services price of $99 million for base Vulcan with no solid rocket boosters.<ref name=reuters20160414>{{Cite news |url=https://www.reuters.com/article/us-space-ula-layoffs-idUSKCN0XB2HQ |title=United Launch Alliance to lay off up to 875 by end of 2017: CEO |date=2016-04-14 |newspaper=Reuters |access-date=2016-05-07}}</ref> Also the ULA team was to be reduced by about one quarter of its legacy workforce, or more than 800 employees, by end 2017 in order to better [[Space launch market competition|compete]] with SpaceX and Blue Origin offerings in the US launch market.<ref name=reuters20160414/>{{update after|2017}} In October 2017, ULA announced that [[Bigelow Aerospace]]'s [[B330]] would be flown on a Vulcan 562 configuration rocket rather than the previously planned [[Atlas V]].<ref name="ula20171017">{{cite press release |url=http://www.ulalaunch.com/bigelow-aerospace-and-ula-lunar-depot.aspx |title=Bigelow Aerospace and United Launch Alliance Announce Agreement to Place a B330 Habitat in Low Lunar Orbit |publisher=United Launch Alliance |date=October 17, 2017 |accessdate=January 18, 2018}}</ref>

A delay was announced in January 2018 pushing first launch back from 2019 to mid-2020.<ref name=SpaceNewsFoust201801/> Also announced was an upgrade to the Centaur second stage to include up to four RL10 engines, to be called [[Centaur V]].<ref>{{cite web |title=Vulcan Centaur |url=https://www.ulalaunch.com/rockets/vulcan-centaur |publisher=ULA |accessdate=16 February 2018}}</ref>{{better source|date=May 2018}} While a tri-core Vulcan Heavy with a payload of {{cvt|50000|lb|order=flip}} had been conceptualized in 2015,<ref name="ula20150505" /> ULA clarified that it would not build a multi-core configuration as the upgrades to the Centaur second stage would allow a single core Vulcan Centaur to lift "30% more" than a [[Delta IV Heavy]].<ref>{{Cite web |author= ToryBruno (President & CEO of ULA) |url= https://www.reddit.com/r/ula/comments/7wxhqc/vulcan_heavy/du4wrv4/ |title= Vulcan Heavy? |website= Reddit.com |date= |access-date=2018-04-12}}</ref> By March 2018, ULA had begun to publicly refer to the new Vulcan first stage with the Centaur V second stage as the ''Vulcan Centaur''.<ref name=sn20180325>{{cite news |last=Erwin|first=Sandra |url=https://tools.wmflabs.org/makeref/ |title=Air Force stakes future on privately funded launch vehicles. Will the gamble pay off? |work=[[SpaceNews]] |date=25 March 2018 |accessdate=2018-06-24}}</ref>

In May 2018, ULA selected Aerojet Rocketdyne's RL10 engine for the Vulcan Centaur upper stage.<ref>{{cite web |last1=Tribou |first1=Richard |url=http://www.orlandosentinel.com/news/space/go-for-launch/os-united-launch-alliance-rocket-aerodyne-vulcan-20180511-story.html |title=ULA chooses Aerojet Rocketdyne over Blue Origin for Vulcan's upper stage engine |work=Orlando Sentinel |date= 11 May 2018 |accessdate= 13 May 2018}}</ref>

== Funding ==
Vulcan is being funded by a combination of [[government funding|government]] and [[private capital|private]] funds.<ref name=sn20160310/><ref name=sn20180325/> The initial private funding for Vulcan development, over the first 18 months since announcement in October 2014, has been approved only for the short term. By April 2015, it became public that the United Launch Alliance board of directors — composed entirely of executives from Boeing and Lockheed Martin — is approving development funding on only a quarter-by-quarter basis.<ref name="dbj20150415">{{cite news |last1=Avery|first1=Greg |title=The fate of United Launch Alliance and its Vulcan rocket may lie with Congress |url= http://www.bizjournals.com/denver/blog/boosters_bits/2015/04/the-fate-of-united-launch-alliance-and-its-vulcan.html?page=all |issue=Denver Business Journal |date=2015-04-16 |accessdate=28 April 2015}}</ref> Funding remained limited to quarterly approvals in June 2015, and Lockheed Martin was actively working to use the funding limitation to get the [[US Congress]] to change existing law and allow extension of ULA ability to acquire [[RD-180]] engines for the [[Atlas V]].<ref>[https://finance.yahoo.com/news/airshow-lockheed-says-rocket-launch-171639395.html "AIRSHOW-Lockheed says rocket launch venture urgently needs U.S. law waiver"]. Yahoo Finance, June 14, 2015.</ref> In March 2016, executives from ULA indicated that the practice of quarter-by-quarter investment for Vulcan development would continue.<ref name=sn20160310>{{cite news |last=Gruss |first=Mike |url=http://spacenews.com/ulas-parent-companies-still-support-vulcan-with-caution/ |title=ULA’s parent companies still support Vulcan … with caution |work=[[SpaceNews]] |date=2016-03-10 |accessdate=2016-03-10}}</ref>

By March 2016, the [[USAF|US Air Force]] had committed up to {{USD|202 million}} of funding for Vulcan development. ULA has not "put a firm price tag on [the total cost of Vulcan development but ULA CEO Tory Bruno has] said new rockets typically cost $2 billion, including $1 billion for the main engine."<ref name=sn20160310/> ULA Board of Directors member, and Boeing executive (President of Boeing's Network and Space Systems (N&SS) division), Craig Cooning said in April 2016 that he is confident that the US Air Force will invest in further funding of Vulcan development costs.<ref name=dd20160412>{{cite news |last=Host|first=Pat |url=http://www.defensedaily.com/cooning-confident-air-force-will-invest-in-vulcan-development/ |title=Cooning Confident Air Force Will Invest In Vulcan Development |work=Defense Daily |date=2016-04-12 |accessdate=2016-04-13}}</ref>

In September 2017 the bill for the proposed [[National Defense Authorization Act]] for [[National Defense Authorization Act for Fiscal Year 2018|Fiscal Year 2018]] carried language in the House version inserted by [[United States House of Representatives|Congressman]] [[Mike Rogers (Alabama politician)|Mike Rogers]]. This language would limit the [[United States Department of Defense|US DoD]], and hence the [[United States Air Force|US Air Force]], from allocating funding to ULA for the Vulcan rocket for the fiscal year 2018. Some news media<ref name=foxb75308d24ee87483>{{cite news |last=Paul |first=Ron |url=https://www.foxnews.com/opinion/2017/09/12/ron-paul-crony-defense-budget-hands-spacex-monopoly-why.html |title=Ron Paul: Crony defense budget hands SpaceX a monopoly - why? |work=[[Fox News]] |date=2017-09-12 |accessdate=2017-11-05}}</ref><ref name=breitbart0e992592a770ea20>{{cite news |last=Garst |first=Brian |url=http://www.breitbart.com/big-government/2017/09/18/elon-musk-giveaways-wont-make-america-safe-again%E2%80%A8/ |title=GARST: Elon Musk Giveaways Won’t ‘Make America Safe Again’ |work=[[Breitbart]] |date=2017-09-18 |accessdate=2017-11-05}}</ref><ref name=washexam8405572c7286f9f9>{{cite news |last=Postell |first=Samuel |url= http://www.washingtonexaminer.com/elon-musks-spacex-is-at-war-with-the-free-market/article/2639005 |title=Elon Musk's SpaceX is at war with the free market |work=[[Washington Examiner]] |date=2017-10-30 |accessdate=2017-11-05}}</ref> suggested that [[United States Senate|US Senator]] [[John McCain]] was the author of this section, even though this section does not exist in the Senate version of the bill, and that it was inserted primarily for the benefit of SpaceX. Other publications noted that [[Aerojet Rocketdyne]] is incorporated in Mike Rogers's constituency and suggested this was inserted to benefit the company's AR1 rocket engine program.<ref name=arstechc5ae6f21863c5dcd>{{cite news |last=Berger |first=Eric |url=https://arstechnica.com/science/2017/11/breitbart-other-conservative-outlets-escalate-anti-spacex-campaign/ |title=Breitbart, other conservative outlets escalate anti-SpaceX campaign |work=[[Ars Technica]] |date=2017-11-01 |accessdate=2017-11-05}}</ref> If this bill were to be passed with section 1615, it may severely limit the funding that the USAF can provide to ULA for the Vulcan program.{{update after|2018|5|13}}

In March 2018, ULA CEO Tory Bruno said "Vulcan Centaur [had been] 75 percent privately funded" up to that time.<ref name=sn20180325/> In 2016, the US Congress had authorized the [[USAF]] to "sign deals with the space industry to co-finance the development of new rocket propulsion systems. The program known as the [[Launch Service Agreement]] (LSA) fits the Air Force's broader goal to get out of the business of "buying rockets" and instead acquire end-to-end [[launch service provider|services]] from companies. The Air Force signed cost-sharing partnerships with [launch vehicle company] [[United Launch Alliance|ULA]], [launch vehicle and rocket engine manufacturers] SpaceX [and] [[Orbital ATK]], and [with rocket engine supplier] [[Aerojet Rocketdyne]]. The original request for proposals noted the Air Force wants to "leverage commercial launch solutions in order to have at least two domestic, commercial launch service providers." The next step is to select three companies [by mid-year 2018] to move forward with launch system prototypes."<ref name=sn20180325/>

== Design approach and description ==
[[File:Blue Origin BE-4 rocket engine, sn 103, April 2018 -- LCH4 inlet side view.jpg|thumb|The first hotfire Blue Origin BE-4 rocket engine at the 34th Space Symposium in Colorado Springs, Colorado, April 2018, showing the liquid methane inlet side of the engine.]]

ULA is taking an incremental approach to the development of their first launch vehicle design<ref name=sn20150413/> but is utilizing various technologies previously developed by its two parent companies: utilizing significant Boeing Delta IV technology as well as Lockheed Martin Atlas technology. In addition, it is maintaining an engine selection competition between engine suppliers Aerojet Rocketdyne and Blue Origin for both the booster and upper stages. It is continuing the tradition of is parent companies to accept a large amount of development funding from the [[Federal government of the United States|US government]], while adding elements of private capital to fund a portion of development cost.<ref name="sn20150413"/><ref name="sn20150424"/><ref name="wsj20150910"/>

The first stage tanks will be derived from those of the Delta IV, using two of the {{convert|550000|lbf|kN|order=flip|adj=on|lk=on}}-thrust [[BE-4]] engines.<ref name="sn20140917" /><ref name="spacenews1">{{cite news |url= http://spacenews.com/ulas-vulcan-rocket-to-be-rolled-out-in-stages/ |publisher= Space News |title= ULA’s Vulcan Rocket To be Rolled out in Stages |date= 13 April 2015 |author= Mike Gruss}}</ref><ref name="aw2015-05-11">{{cite news |first=Amy |last=Butler |url=http://aviationweek.com/space/industry-team-hopes-resurrect-atlas-v-post-rd-180 |title=Industry Team Hopes To Resurrect Atlas V Post RD-180 |work=[[Aviation Week & Space Technology]] |date=11 May 2015 |accessdate=12 May 2015 |archive-url=https://web.archive.org/web/20150512205445/http://aviationweek.com/space/industry-team-hopes-resurrect-atlas-v-post-rd-180 |archive-date=12 May 2015 |deadurl=no}}</ref> At announcement in 2014, the engine was already in its third year of development by Blue Origin, and ULA expected the new stage and engine to start flying no earlier than 2019.

Vulcan will initially use an upgraded variant of the [[Centaur (rocket stage)|Centaur]] upper stage used on Atlas V, later to be upgraded to ACES.<ref>{{cite news |url= http://spacenews.com/op-ed-building-on-a-successful-record-in-space-to-meet-the-challenges-ahead/ |publisher= Space News |title= Building on a successful record in space to meet the challenges ahead |date= 10 October 2017 |author= Bruno, Tory}}</ref> It will also use a variable number of optional solid rocket boosters, called the [[Graphite-Epoxy Motor]] (GEM) 63XL, derived from the new solid boosters planned for Atlas V.<ref name=sfi20150923>{{cite news |url= http://www.spaceflightinsider.com/organizations/ula/ula-selects-orbital-atks-gem-6363-xl-srbs-for-atlas-v-and-vulcan-boosters/ |title= ULA selects Orbital ATK’s GEM 63/63 XL SRBs for Atlas V and Vulcan boosters |author= Jason Rhian |date= 23 September 2015 |publisher= Spaceflight Insider}}</ref> With a {{nowrap|4-meter}} diameter payload fairing it can use up to four SRBs, and with a {{nowrap|5-meter}} fairing it can use up to six SRBs.The first stage can optionally have from zero to six [[solid rocket booster]]s (SRBs),<ref name=Apr2015/>

In August 2016 ULA's President and CEO said they intend to [[human-rating certification|human rate]] both the Vulcan and ACES.<ref name="Man_rate">{{cite web |last1=Tory Bruno |title="@A_M_Swallow @ULA_ACES We intend to human rate Vulcan/ACES" |url=https://twitter.com/torybruno/status/770579558726668288 |website=Twitter.com |accessdate=August 30, 2016}}</ref>

ULA is designing two versions of the Vulcan first stage, one using the BE-4 with a {{convert|5.4|m|ft|sp=us|abbr=on|adj=on}} outer diameter to support the less-dense [[liquid methane|methane]] fuel and an [[AR1 (rocket engine)|AR1]] design with the same {{convert|3.81|m|ft|sp=us|abbr=on|adj=on}} diameter as Atlas V for the denser {{nowrap|[[RP-1]]}} (kerosene) fuel.<ref name=sn20160316/>

==Engine choice==
A competition among engine vendors, [[Blue Origin]] and [[Aerojet Rocketdyne]] has been underway since approximately 2014, with final engine selection originally slated for 2017<ref name=sn20170405/> but subsequently moved to 2018.

In April 2017, just as a major series of ground tests of the Blue Origin [[BE-4]] were set to occur over the summer, ULA indicated that Blue continued to lead, but the final selection would not be made until after the test series is complete, particularly a variety of tests aimed at characterizing any [[combustion instability]] in the design.<ref name=sn20170405>[http://spacenews.com/bruno-vulcan-engine-downselect-is-blues-to-lose/ "Bruno: Vulcan engine downselect is Blue's to lose"]. Space News, April 5, 2017</ref> Blue Origin experienced a test anomaly on 13 May 2017 reporting that they lost a set of BE-4 [[Powerpack (rocket engine)|powerpack]] hardware.<ref>[http://spacenews.com/blue-origin-suffers-be-4-testing-mishap/ "Blue Origin suffers BE-4 testing mishap"]. Space News, May 15, 2017.</ref>

The BE-4 was first test-fired, at 50 percent thrust for three seconds, in October 2017.<ref name=ars20171019>{{cite news |last1=Berger |first1=Eric |title=Blue Origin just sent a jolt through the aerospace industry |url=https://arstechnica.com/science/2017/10/blue-origin-has-successfully-tested-its-powerful-be-4-rocket-engine/ |publisher=Ars Technica |date=19 October 2017 |accessdate=19 October 2017}}</ref> As of February 2018, Aerojet Rocketdyne is asking for additional funds from USAF to complete work on the AR-1 engine.<ref>{{cite news |last1=Foust |first1=Jeff |title=Air Force and Aerojet Rocketdyne renegotiating AR1 agreement |url=http://spacenews.com/air-force-and-aerojet-rocketdyne-renegotiating-ar1-agreement/ |publisher=Space News |date=16 February 2018}}</ref>

== References ==
{{Reflist|30em}}

== External links ==
* {{Official website|www.ulalaunch.com/Products_Vulcan.aspx}}
* [https://www.youtube.com/watch?v=xTTkrxVR_20 ISPCS 2015 Keynote], Mark Peller, Program Manager of Major Development at ULA and Vulcan Program Manager discusses Vulcan, 8 October 2015. Key discussion of Vulcan is at 12:20 point in video.

{{Expendable launch systems}}
{{US launch systems}}
{{Reusable launch systems}}

[[Category:Space launch vehicles of the United States]]
[[Category:United Launch Alliance]]

McGregor, Texas

2018-06-25T20:07:33Z

Blastr42: /* Economy */Added Bluebonnet Ordnance Plant history

{{Infobox settlement
|official_name = McGregor, Texas
|settlement_type = [[City]]
|nickname =
|motto =


|image_skyline =
|imagesize =
|image_caption =
|image_flag =
|image_seal =


|image_map = TXMap-doton-McGregor.PNG
|mapsize = 250px
|map_caption = Location of McGregor, Texas
|image_map1 = McLennan County McGregor.svg
|mapsize1 = 250px
|map_caption1 =


|subdivision_type = [[List of sovereign states|Country]]
|subdivision_name = United States
|subdivision_type1 = [[U.S. state|State]]
|subdivision_name1 = [[Texas]]
|subdivision_type2 = [[List of counties in Texas|Counties]]
|subdivision_name2 = [[McLennan County, Texas|McLennan]], [[Coryell County, Texas|Coryell]]


|government_footnotes =
|government_type =
|leader_title =
|leader_name =
|leader_title1 =
|leader_name1 =
|established_title =
|established_date =


|unit_pref = Imperial
|area_footnotes =
|area_magnitude =
|area_total_km2 = 55.5
|area_land_km2 = 55.5
|area_water_km2 = 0.0
|area_total_sq_mi =
|area_land_sq_mi =
|area_water_sq_mi =


|population_as_of = [[2010 United States Census|2010]]
|population_footnotes =
|population_total = 4987
|population_density_km2 = 89.9
|population_density_sq_mi =


|timezone = [[North American Central Time Zone|Central (CST)]]
|utc_offset = -6
|timezone_DST = CDT
|utc_offset_DST = -5
|elevation_footnotes =
|elevation_m = 211
|elevation_ft = 692
|coordinates = {{coord|31|25|55|N|97|25|1|W|region:US_type:city|display=inline,title}}
|postal_code_type = [[ZIP code]]
|postal_code = 76657
|area_code = [[Area code 254|254]]
|blank_name = [[Federal Information Processing Standard|FIPS code]]
|blank_info = 48-45672<ref name="GR2">{{cite web|url=http://factfinder2.census.gov |publisher=[[United States Census Bureau]] |accessdate=2008-01-31 |title=American FactFinder |deadurl=yes |archiveurl=https://web.archive.org/web/20130911234518/http://factfinder2.census.gov/ |archivedate=September 11, 2013 |df= }}</ref>
|blank1_name = [[Geographic Names Information System|GNIS]] feature ID
|blank1_info = 1362469<ref name="GR3">{{cite web|url=http://geonames.usgs.gov|accessdate=2008-01-31|title=US Board on Geographic Names|publisher=[[United States Geological Survey]]|date=2007-10-25}}</ref>
|website = {{URL|www.mcgregor-texas.com}}
|footnotes =
}}
'''McGregor''' is a city in [[McLennan County, Texas|McLennan]] and [[Coryell County, Texas|Coryell]] counties in the [[U.S. state]] of [[Texas]]. The population was 4,987 at the 2010 census.<ref name="Census 2010">{{cite web| url=http://factfinder.census.gov/bkmk/table/1.0/en/DEC/10_SF1/G001/1600000US4845672| title=Geographic Identifiers: 2010 Census Summary File 1 (G001): McGregor city, Texas| publisher=U.S. Census Bureau, American Factfinder| accessdate=August 6, 2015}}</ref>

McGregor lies in two counties, as well as two metropolitan areas. The McLennan County portion of the city is part of the [[Waco, Texas|Waco]] [[Waco metropolitan area|Metropolitan Statistical Area]], while the small portion that lies in Coryell County is part of the [[Killeen, Texas|Killeen]]–[[Temple, Texas|Temple]]–[[Fort Hood]] [[Killeen-Temple-Fort Hood metropolitan area|Metropolitan Statistical Area]].

==Geography==
McGregor is located in western McLennan County at {{coord|31|25|55|N|97|25|1|W|type:city}} (31.431928, -97.417022).<ref name="GR1">{{cite web|url=https://www.census.gov/geo/www/gazetteer/gazette.html|publisher=[[United States Census Bureau]]|accessdate=2011-04-23|date=2011-02-12|title=US Gazetteer files: 2010, 2000, and 1990}}</ref> It extends westward into Coryell County, surrounding McGregor Industrial Park, a former Naval Weapons Reserve Plant.<ref>{{Cite web| url=http://www.mcgregor-texas.com/ecodev/popupp.htm| title=Industrial Park| publisher=McGregor Economic Development Corporation| accessdate=August 6, 2015}}</ref>

[[U.S. Route 84]] passes through the city center, leading northeast {{convert|17|mi}} to [[Waco, Texas|Waco]] and west {{convert|20|mi}} to [[Gatesville, Texas|Gatesville]]. [[Texas State Highway 317]] crosses US 84 near the city center, leading north {{convert|15|mi}} to [[Valley Mills, Texas|Valley Mills]] and south {{convert|28|mi}} to [[Belton, Texas|Belton]].

According to the [[United States Census Bureau]], McGregor has a total area of {{convert|55.5|sqkm|order=flip}}, all of it land.<ref name="Census 2010"/>

==Demographics==
{{US Census population
|1890= 774
|1900= 1435
|1910= 1864
|1920= 2081
|1930= 2041
|1940= 2062
|1950= 2669
|1960= 4642
|1970= 4365
|1980= 4513
|1990= 4683
|2000= 4727
|2010= 4987
|estyear=2016
|estimate=5071
|estref=<ref name="USCensusEst2016">{{cite web|url=https://www.census.gov/programs-surveys/popest/data/tables.2016.html|title=Population and Housing Unit Estimates|accessdate=June 9, 2017}}</ref>
|footnote=U.S. Decennial Census<ref name="DecennialCensus">{{cite web|url=https://www.census.gov/prod/www/decennial.html|title=Census of Population and Housing|publisher=Census.gov|accessdate=June 4, 2015|deadurl=yes|archiveurl=https://www.webcitation.org/6YSasqtfX?url=http://www.census.gov/prod/www/decennial.html|archivedate=May 12, 2015|df= }}</ref>
}}
As of the [[census]]<ref name="GR2" /> of 2000, 4,727 people, 1,728 households, and 1,206 families resided in the city. The [[population density]] was 216.7 people per square mile (83.6/km²). There were 1,856 housing units at an average density of 85.1/sq mi (32.8/km²). The [[Race (United States Census)|racial makeup]] of the city was 71.10% White, 11.53% African American, 1.02% Native American, 0.38% Asian, 14.41% from other races, and 1.57% from two or more races. Hispanics or Latinos of any race were 27.27% of the population.

Of the 1,728 households, 33.1% had children under the age of 18 living with them, 51.4% were [[Marriage|married couples]] living together, 13.4% had a female householder with no husband present, and 30.2% were not families. About 27.7% of all households were made up of individuals, and 15.2% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 3.21.

In the city, the population was distributed as 27.7% under the age of 18, 9.1% from 18 to 24, 25.4% from 25 to 44, 18.6% from 45 to 64, and 19.3% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 85.6 males. For every 100 females age 18 and over, there were 81.1 males.

The median income for a household in the city was $33,200, and for a family was $37,143. Males had a median income of $31,250 versus $18,605 for females. The [[per capita income]] for the city was $16,311. About 10.9% of families and 14.9% of the population were below the [[poverty line]], including 19.1% of those under age 18 and 16.3% of those age 65 or over.

==Economy==
McGregor is the site of the former Bluebonnet Ordnance Plant to make munitions during World War II. After the war, the site has been used by a number of companies to make rockets, including Phillips, Rocketdyne, Hercules and Beal Aerospace. <ref>{{Cite web|url=http://www.kwtx.com/content/news/Before-SpaceX-McGregor-facility-produced-bombs-and-lots-of-them-430442353.html|title=McGregor: Before SpaceX, facility produced bombs and lots of them|last=Gately|first=Paul J.|website=www.kwtx.com|access-date=2018-06-25}}</ref>
[[SpaceX]] has a [[SpaceX launch facilities#SpaceX Rocket Development and Test Facility.2C McGregor.2C Texas|rocket engine development and test facility in McGregor]]. SpaceX acquired the facility from defunct [[Beal Aerospace]] that had established it as a rocket engine test facility. In May 2016, McGregor passed an ordinance to reduce noise and vibration caused by SpaceX testing activity.<ref>{{Cite web|url=http://www.kwtx.com/content/news/McGregor--City-modifies-SpaceX-rocket-testing-rules-378857891.html|title=McGregor: City modifies SpaceX rocket testing rules|last=Lopez|first=Paul J. Gately and Ke'Sha|website=www.kwtx.com|access-date=2016-05-11}}</ref>

McGregor is the home of Magnolia House, a Victorian property renovated in Season 3 of HGTV's ''[[Fixer Upper (TV series)|Fixer Upper]]'' by Chip and Joanna Gaines. It now operates as a bed and breakfast.<ref>{{cite web|title=Magnolia House|url=https://magnoliamarket.com/stay/|accessdate=23 May 2017}}</ref>

==Education==
The city is served by the [[McGregor Independent School District]] and the [[Midway Independent School District (McLennan County, Texas)|Midway Independent School District]]

==Transportation==
* [[McGregor station (Texas)]]

==Climate==
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the [[Köppen Climate Classification]] system, McGregor has a [[humid subtropical climate]], abbreviated "Cfa" on climate maps.<ref>[http://www.weatherbase.com/weather/weather-summary.php3?s=757514&cityname=McGregor%2C+Texas%2C+United+States+of+America&units= Climate Summary for McGregor, Texas]</ref>

==References==
<references />

==External links==
* [http://www.mcgregor-texas.com City of McGregor official website]

{{Coryell County, Texas}}
{{McLennan County, Texas}}

[[Category:Cities in McLennan County, Texas]]
[[Category:Cities in Texas]]
[[Category:Cities in Coryell County, Texas]]
[[Category:Killeen – Temple – Fort Hood metropolitan area]]

Bob Behnken

2018-06-13T18:13:26Z

Blastr42: /* Personal life */

{{short description|United States Air Force officer, NASA astronaut and former Chief of the Astronaut Office }}
{{Infobox astronaut
| name = Robert L. Behnken
| image = Robertbehnkenv2.jpg
| type = [[NASA]] Astronaut
| status = Active
| nationality = American
| birth_date = {{Birth date and age|1970|7|28}}
| death_date =
| birth_place = [[Creve Coeur, Missouri]], U.S.
| death_place =
| occupation = [[Test engineer]]
| rank = [[Colonel]], [[United States Air Force|USAF]]
| selection = [[List of astronauts by selection#2000|2000 NASA Group]]
| space_time = 29d 12h 17m
| evas = 6
| eva_time = 37 hours, 33 minutes
| missions = [[STS-123]], [[STS-130]]
| insignia = [[File:STS-123 Patch.svg|50px]] [[File:STS-130 patch.png|30px]]
}}

'''Robert Louis "Bob" Behnken''' (born July 28, 1970 in [[Creve Coeur, Missouri]]) is a [[United States Air Force]] officer, [[NASA]] [[astronaut]] and former [[Chief of the Astronaut Office]]. Behnken holds a [[Ph.D]] in [[Mechanical Engineering]] and holds the rank of [[Colonel]] in the U.S. Air Force. Col. Behnken has logged over 1,000 flight hours in 25 different aircraft. He flew aboard [[Space Shuttle]] missions [[STS-123]] and [[STS-130]] as a [[Mission Specialist]], accumulating over 378 hours in space, including 19 hours of [[spacewalk]] time. Behnken was also assigned as Mission Specialist 1 to the [[STS-400]] rescue mission. He is married to fellow astronaut [[K. Megan McArthur]].<ref>[http://www.msnbc.msn.com/id/30561750/ Astronauts eager for last Hubble visit: Final telescope servicing mission brings veterans and rookies together] 2009-05-04</ref>

==Education==

Behnken attended [[Pattonville High School]] in [[Maryland Heights, Missouri]] (in [[St. Louis County, Missouri|St. Louis County]]), and went on to earn [[Bachelor of Science]] degrees in [[Mechanical Engineering]] and [[Physics]] from [[Washington University in St. Louis]] in 1992. He attended [[Caltech]] for graduate school, where he earned a [[Master of Science]] degree in Mechanical Engineering in 1993, and a [[Doctorate|doctoral degree]] in 1997.<ref name="bio">{{Cite web |url=http://www.jsc.nasa.gov/Bios/htmlbios/behnken-rl.html |title=Robert L. Behnken |accessdate=September 2, 2008 |publisher=[[NASA]] |year=2008 |author=[[National Aeronautics and Space Administration]]}}</ref>

==Awards and honors==
* Outstanding [[Mechanical Engineering]] Senior, Washington University (1992)
* [[National Science Foundation]] Graduate Research Fellow (1993–1996)
* [[Air Force Research Laboratory]] Munitions Directorate, Eglin AFB, Company Grade Officer of the Year (1997)
* [[Air Force Achievement Medal]] (1997); [[Air Force Commendation Medal]] (1998, 2000)
* Distinguished graduate from the USAF Test Pilot School Program (1999)
* Recipient of the USAF Test Pilot School Colonel Ray Jones Award as the top [[Flight test engineer|Flight Test Engineer]]/Flight Test Navigator in class 98B.<ref name="bio" />

==Career==
Behnken's graduate thesis research was in the area of [[nonlinear control]] applied to stabilizing rotating stall and surge in [[axial-flow compressor]]s. The research included nonlinear analysis, real-time software implementation development, and extensive hardware construction. During his first two years of [[Graduate school|graduate]] study, Behnken developed and implemented real-time control algorithms and hardware for flexible robotic manipulators.<ref name="bio" />

Prior to entering graduate school, Behnken was an [[Air Force Reserve Officer Training Corps|Air Force ROTC]] student at [[Washington University in St. Louis]], and after [[graduate school]] was assigned to enter [[United States Air Force|Air Force]] active duty at [[Eglin AFB]], [[Florida]]. While at Eglin, he worked as a technical manager and developmental engineer for new [[munition]]s systems. Behnken was next assigned to attend the [[U.S. Air Force Test Pilot School]] Flight Test Engineer's course at [[Edwards AFB]], [[California]]. After graduating, he was assigned to the [[F-22]] Combined Test Force (CTF) and remained at Edwards. While assigned to the F-22 program, Behnken was the lead flight test engineer for Raptor 4004 and a special projects test director. These responsibilities included flight test [[sortie]] planning, control room configuration development, and test conduct. Behnken also flew in both the [[F-15 Eagle|F-15]] and [[F-16]] [[aircraft]] in support of the F-22 flight test program.<ref name="bio" />

Behnken has over 780 flight hours in more than 25 different aircraft types.

==NASA career==
[[File:STS-130 EVA1 Robert Behnken and Nicholas Patrick 1.jpg|thumb|left|Astronauts Robert L. Behnken and [[Nicholas Patrick]] carrying out spacewalk during STS-130 mission.]]
Selected as an astronaut candidate by NASA in July 2000, Behnken reported for training in August 2000. Following the completion of 18 months of training and evaluation, he was assigned technical duties in the Astronaut Office Shuttle Operations Branch supporting launch and landing operations at [[Kennedy Space Center]], Florida.

In September 2006, Behnken served as an [[aquanaut]] during the [[NEEMO#NEEMO 11: September 16–22, 2006|NEEMO 11]] mission aboard the [[Aquarius (laboratory)|Aquarius]] [[Underwater habitat|underwater laboratory]], living and working underwater for seven days.<ref>{{Cite web |url=http://www.nasa.gov/mission_pages/NEEMO/NEEMO11/index.html |title=NASA – NEEMO 11 |author=NASA |publisher=NASA |date=May 11, 2010 |accessdate=September 26, 2011}}</ref>
===STS-123===
Behnken was a crew member of the [[STS-123]] mission that delivered the [[Japanese Experiment Module]] and the [[Dextre|Special Purpose Dexterous Manipulator]] to the [[International Space Station]] in March 2008.<ref name="bio" /> Behnken took part in three [[Extra-vehicular activity|spacewalks]] during the mission.
===STS-130===
Behnken also flew as a Mission Specialist on [[STS-130]], which launched at 04:14 EST (09:14 UTC) 8 February 2010. This mission delivered the [[Tranquility (ISS module)|Tranquility]] module and Cupola to the [[International Space Station]]. Behnken again took part in three spacewalks during this mission.<ref name="Summary">{{cite web |url=http://www.nasa.gov/pdf/415450main_STS130_Mission_Summary_1-5-10.pdf |title=STS-130 Mission Summary |author=NASA |date=February 2010 |publisher=NASA |accessdate=January 12, 2012}}</ref>
===Chief of the Astronaut Office===
In July 2012, Behnken was named [[Chief of the Astronaut Office]], succeeding [[Peggy Whitson]]. He held the job until July 2015, when he was succeeded by [[Christopher Cassidy|Chris Cassidy]], after being selected as one of four astronauts training to fly spacecraft contracted under NASA's [[Commercial Crew Development|Commercial Crew Program]].<ref>{{cite web |url=http://www.nasaspaceflight.com/2015/07/navy-seal-new-chief-astronaut-office/ |title=Captain Cassidy – From Navy SEAL to Chief of the Astronaut Office |last=Bergin |first=Chris |publisher=nasaspaceflight.com |date=9 July 2015}}</ref>

== Personal life ==

Behnken is married to fellow astronaut [[K. Megan McArthur]].

==References==
{{reflist}}
''This article incorporates text in the [[public domain]] from the [[National Aeronautics and Space Administration]].''

==External links==
* [http://www.jsc.nasa.gov/Bios/htmlbios/behnken-rl.html NASA biography of Robert L. Behnken]
* [http://www.spacefacts.de/bios/astronauts/english/behnken_robert.htm Spacefacts biography of Robert L. Behnken]

{{s-start}}
{{s-bef|before=[[Peggy Whitson]]}}
{{s-ttl|title=[[Chief of the Astronaut Office]]|years=2012–2015}}
{{s-aft|after=[[Christopher Cassidy]]}}
{{end}}

{{NASA Astronaut Group 18}}

{{DEFAULTSORT:Behnken, Robert L.}}
[[Category:1970 births]]
[[Category:Living people]]
[[Category:American astronauts]]
[[Category:Aquanauts]]
[[Category:United States Air Force astronauts]]
[[Category:People from St. Louis County, Missouri]]
[[Category:Washington University in St. Louis alumni]]
[[Category:California Institute of Technology alumni]]
[[Category:U.S. Air Force Test Pilot School alumni]]
[[Category:United States Air Force officers]]
[[Category:American engineers]]

H-IIA

2018-05-17T23:59:36Z

Blastr42:

{{Other uses|H2A (disambiguation)}}

{{Infobox rocket
|name =H-IIA
|image =H IIA No. F23 with GPM on its way to the launchpad.jpg
|imsize = 300
|caption = H-IIA No. F23 rolls out to the launch pad in February 2014
|function = [[Medium-lift launch vehicle]]
|manufacturer = {{plainlist|
* [[Mitsubishi Heavy Industries]] (prime)
* [[Alliant Techsystems|ATK]] (sub)
}}
|country-origin = [[Japan]]
|cpl-year =
|cpl = {{US$|90 million[http://www.gao.gov/products/GAO-17-609]}}
|height = {{cvt|53|m}}
|diameter = {{cvt|4|m}}
|mass = {{cvt|285,000-445,000|kg}}
|stages = 2
|family = [[H-II (rocket family)|H-II]]
|derivatives = [[H-IIB]]
|capacities = 
{{Infobox rocket/payload
|location = [[Low Earth orbit|LEO]] 
|kilos = {{cvt|10,000-15,000|kg}} 
}}
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]] 
|kilos = {{cvt|4,100-6,000|kg}} 
}}

|status = Active
|sites = [[Tanegashima Space Center|Tanegashima]] [[Yoshinobu Launch Complex|LA-Y]]
|first = {{plainlist|
* '''202:''' 29 August 2001
* '''204:''' 18 December 2006
* '''2022:''' 26 February 2005
* '''2024:''' 4 February 2002
}}
|last = {{plainlist|
* '''202:''' 27 February 2018
* '''204:''' 19 August 2017
* '''2022:''' 14 September 2007
* '''2024:''' 23 February 2008
}}
|launches = {{flatlist|
* 38
** '''202:''' 24
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 7
}}
|success = {{flatlist|
* 37
** '''202:''' 24
** '''204:''' 4
** '''2022:''' 3
** '''2024:''' 6
}}
|fail =1 ('''2024''')
|partial =
|other =
|payloads = {{flatlist|
* [[SELENE]]
* [[Greenhouse Gases Observing Satellite|Ibuki]]
* [[Akatsuki (probe)|Akatsuki]]
}}


|stagedata =
{{Infobox rocket/stage
|type = booster 
|diff = All variants 
|stageno = 
|name = [[SRB-A]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|2,260|kN}} 
|total = {{cvt|4,520–9,040|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 120 seconds 
|fuel = [[HTPB]] 
}}
{{Infobox rocket/stage
|type = booster 
|diff = 2022 / 2024 
|stageno = 
|name = [[Castor (rocket stage)|Castor 4A-XL]] 
|number = 2–4 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 
|solid = yes 
|thrust = {{cvt|745|kN}} 
|total = {{cvt|1,490–2,980|kN}} 
|SI = {{convert|280|isp}} 
|burntime = 60 seconds 
|fuel = [[Solid rocket|Solid]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = First 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-7A]] 
|solid = 
|thrust = {{cvt|1,098|kN}} 
|total = 
|SI = {{convert|440|isp}} 
|burntime = 390 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
{{Infobox rocket/stage
|type = stage 
|diff = 
|stageno = Second 
|name = 
|number = 
|length = 
|diameter = 
|width = 
|empty = 
|gross = 
|propmass = 
|engines = 1 [[LE-5B]] 
|solid = 
|thrust = {{cvt|137|kN}} 
|total = 
|SI = {{convert|447|isp}} 
|burntime = 534 seconds 
|fuel = [[LOX]] / [[Liquid hydrogen|LH2]] 
}}
}}
[[Image:H-IIA F19 launching IGS-O4.jpg|right|250px|thumb|Liftoff of H-IIA Flight 19]]
[[Image:H-IIA Family.png|right|250px|thumb|H-IIA rocket lineup]]
[[Image:H-IIA-Launch-Vehicle.png|thumb|80px|H-IIA]]

'''H-IIA''' ('''H2A''') is an active [[expendable launch system]] operated by [[Mitsubishi Heavy Industries]] (MHI) for the [[JAXA|Japan Aerospace Exploration Agency]]. The liquid-fueled H-IIA [[rocket]]s have been used to launch [[satellite]]s into [[geostationary orbit]], to launch a lunar orbiting spacecraft, and to launch ''[[Akatsuki (spacecraft)|Akatsuki]]'', which studied the planet Venus. Launches occur at the [[Tanegashima Space Center]]. The H-IIA first flew in 2001. {{As of|December 2017}}, H-IIA rockets were launched 37 times, including 31 consecutive missions without a failure, dating back to November 29, 2003.

Production and management of the H-IIA shifted from JAXA to MHI on April 1, 2007. Flight 13, which launched the lunar orbiter [[SELENE]], was the first H-IIA launched after this privatization.<ref>{{cite web|url=http://www.satnews.com/stories2007/4356/ |title=Mitsubishi and Arianespace Combine Commercial Satellite Launch Services |publisher=SatNews |deadurl=yes |archiveurl=https://web.archive.org/web/20120208014829/http://www.satnews.com/stories2007/4356/ |archivedate=February 8, 2012 }}</ref>

The H-IIA is a derivative of the earlier [[H-II]] rocket, substantially redesigned to improve reliability and minimize costs. There are currently two (formerly four) different variants of the H-IIA in active service for various purposes. A derivative design, the [[H-IIB]], was developed in the 2000s and made its [[maiden flight]] in 2009.

== Vehicle description ==
The launch capability of an H-IIA launch vehicle can be enhanced by adding [[SRB-A]] ([[solid rocket booster]] or SRB) and [[Castor (rocket stage)|Castor 4AXL]] (solid strap-on booster or SSB) to its basic configuration, creating a "family". The models are indicated by three or four numbers following the prefix "H2A". The first number in the sequence indicates the number of stages; the second number of [[liquid rocket booster]]s (LRBs); the third number of SRBs; and, if present, the fourth number shows the number of SSBs.<ref name="leaflet">{{cite web |url=http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |title=H-IIA Launch Vehicle |accessdate=2007-09-15 |format=PDF |publisher=JAXA |pages=2 |deadurl=yes |archiveurl=https://web.archive.org/web/20080228013323/http://www.jaxa.jp/pr/brochure/pdf/01/rocket01.pdf |archivedate=2008-02-28 |df= }}</ref> The first two figures are virtually fixed at "20", as H-IIA is always two-staged, and the plans for LRBs were cancelled and superseded by the [[H-IIB]].

== Variants ==

{| class="wikitable"
|-
! Designation!!Mass (tonnes)!!Payload (tonnes to [[Geostationary transfer orbit|GTO]])!!Addon modules
|-
| H2A 202||285||4.1||2 [[SRB-A]] (SRB)
|-
| H2A 2022 (discontinued)<ref>[https://web.archive.org/web/20070105140945/http://www.nikkei.co.jp/news/sangyo/20061205AT1D0300504122006.html 三菱重工、「H2A」2機種に半減・民営化でコスト減]. NIKKEI NET</ref>||316||4.5||2 SRB-A (SRB) + 2 [[Castor (rocket stage)|Castor 4AXL]] (SSB)
|-
| H2A 2024 (discontinued)||347||5||2 SRB-A (SRB) + 4 Castor 4AXL (SSB)
|-
| H2A 204||445||6||4 SRB-A (SRB)
|-
| H2A 212 (cancelled)||403||7.5||2 SRB-A (SRB) + 1 LRB
|-
| H2A 222 (cancelled)||520||9.5||2 SRB-A (SRB) + 2 LRBs
|}

== Launch history ==
{{main|List of H-I and H-II launches}}

The first H-IIA was successfully launched on August 29, 2001, followed by a string of successes.

The sixth launch on November 29, 2003, intended to launch two [[Information Gathering Satellite|IGS]] [[reconnaissance satellite]]s, failed. JAXA announced that launches would resume in 2005, and the first successful flight took place on February 26 with the launch of [[Multi-Functional Transport Satellite|MTSAT-1R]].

The first launch for a mission beyond Earth orbit was on September 14, 2007 for the [[SELENE]] moon mission. The first foreign payload on the H-IIA was the Australian FedSat-1 in 2002. As of March 2015, 27 out of 28 launches were successful.

A rocket with increased launch capabilities, [[H-IIB]], is a derivative of the H-IIA family. H-IIB uses two LE-7A engines in its first stage, as opposed to one in H-IIA. The first H-IIB was successfully launched on September 10, 2009.

For the 29th flight on November 24, 2015, an H-IIA with an upgraded second stage<ref>{{Cite web |url=http://global.jaxa.jp/press/2015/11/20151124_h2af29.html|title=Launch Result of Telstar 12 VANTAGE by H-IIA Launch Vehicle No. 29|publisher=JAXA|date=24 Nov 2015|accessdate=30 Nov 2015}}</ref> launched the Canadian Telstar 12V satellite, the first commercial primary payload for a Japanese launch vehicle.<ref>{{Cite web |url=http://www.nasaspaceflight.com/2015/11/japanese-h-iia-telstar-12v-launch/|title=Japanese H-IIA successfully lofts Telstar 12V|publisher=NASASpaceflight.com|author=William Graham|date=23 Nov 2015|accessdate=30 Nov 2015}}</ref>

{| class="wikitable"
!Date ([[UTC]]) !! Flight !! Type !! Payload(s) !! Outcome
|-
| August 29, 2001 07:00:00 || TF1 || H2A 202|| {{flagicon|Japan}} VEP 2 {{flagicon|Japan}} LRE || {{Success}}
|-
| February 4, 2002 02:45:00 || TF2 || H2A 2024 || {{flagicon|Japan}} VEP 3 {{flagicon|Japan}} [[MDS-1]] (Tsubasa) {{flagicon|Japan}} DASH || {{Success}}
|-
| September 10, 2002 08:20:00 || F3 || H2A 2024 || {{flagicon|Japan}} [[USERS]] {{flagicon|Japan}} [[DRTS]] (Kodama) || {{Success}}
|-
| December 14, 2002 01:31:00 || F4 || H2A 202 || {{flagicon|Japan}} [[ADEOS 2]] (Midori 2) {{flagicon|Japan}} WEOS (Kanta-kun) {{flagicon|Australia}} [[FedSat]] 1 {{flagicon|Japan}} Micro LabSat 1 || {{Success}}
|-
| March 28, 2003 01:27:00 || F5 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 1 {{flagicon|Japan}} IGS-Radar 1 || {{Success}}
|-
| rowspan=2 | {{nobr|November 29, 2003}} 04:33:00 || rowspan=2 | F6 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical (2) {{flagicon|Japan}} IGS-Radar (2) || {{Failure}}
|-
| colspan=3 style="background:linen;" | A hot gas leak from one SRB-A motor destroyed its separation system. The strap-on did not separate as planned, and the weight of the spent motor prevented the vehicle from achieving its planned height.<ref>{{cite web |url=http://www.jaxa.jp/press/2003/11/20031129_h2af6_e.html |title=Launch Result of IGS #2/H-IIA F6 |date=November 29, 2003 |accessdate=June 19, 2013 |publisher=JAXA}}</ref>
|-
| February 26, 2005 09:25:00 || F7 || H2A 2022 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-1R]] (Himawari 6) || {{Success}}
|-
| January 24, 2006 01:33:00 || F8 || H2A 2022 || {{flagicon|Japan}} [[ALOS]] (Daichi) || {{Success}}
|-
| February 18, 2006 06:27:00 || F9 || H2A 2024 || {{flagicon|Japan}} [[Multi-Functional Transport Satellite|MTSAT-2]] (Himawari 7) || {{Success}}
|-
| September 11, 2006 04:35:00 || F10 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 2 || {{Success}}
|-
| December 18, 2006 06:32:00 || F11 || H2A 204 || {{flagicon|Japan}} [[ETS-VIII]] (Kiku 8) || {{Success}}
|-
| February 24, 2007 04:41:00 || F12 || H2A 2024 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 2 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3V || {{Success}}
|-
| September 14, 2007 01:31:01 || F13 || H2A 2022 || {{flagicon|Japan}} [[SELENE]] (Kaguya) || {{Success}}
|-
| February 23, 2008 08:55:00 || F14 || H2A 2024 || {{flagicon|Japan}} [[WINDS]] (Kizuna) || {{Success}}
|-
| January 23, 2009 03:54:00 || F15 || H2A 202 || {{flagicon|Japan}} [[GOSAT]] (Ibuki) {{flagicon|Japan}} [[SDS-1]] {{flagicon|Japan}} STARS (Kūkai) {{flagicon|Japan}} KKS-1 (Kiseki) {{flagicon|Japan}} PRISM (Hitomi) {{flagicon|Japan}} [[Sohla]]-1 (Maido 1) {{flagicon|Japan}} SORUNSAT-1 (Kagayaki) {{flagicon|Japan}} SPRITE-SAT (Raijin) || {{Success}}<ref>{{cite web |url=http://www.jaxa.jp/press/2009/01/20090123_h2a-f15_e.html |title=Launch Result of the IBUKI (GOSAT) by H-IIA Launch Vehicle No. 15 |date=January 23, 2009 |publisher=MHI and JAXA}}</ref>
|-
| November 28, 2009 01:21:00 <ref>{{cite web|url=http://www.sorae.jp/030801/3328.html|title=H-IIA F16|publisher=Sorae|deadurl=yes|archiveurl=https://www.webcitation.org/64qmnLLfk?url=http://www.sorae.jp/030801/3328.html|archivedate=2012-01-21|df=}}</ref> || F16 || H2A 202|| {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 3|| {{Success}}
|-
| May 20, 2010 21:58:22<ref>{{cite web |url=http://www.jaxa.jp/press/2010/03/20100303_h2af17_e.html |title=Launch Day of the H-IIA Launch Vehicle No. 17 |date=March 3, 2010 |publisher=JAXA}}</ref><ref>{{cite web |url=http://www.jaxa.jp/countdown/f17/overview/sub_payload_e.html |title=Overview of Secondary Payloads |publisher=JAXA}}</ref><ref>{{Cite web |url=http://www.space.com/missionlaunches/japan-venus-probe-launch-thursday-100518.html|title=New Venus Probe to Launch Thursday From Japan After|publisher=space.com|author=Tariq Malik|date=18 May 2010|accessdate=20 May 2010}}</ref> || F17 || H2A 202<ref name="nasa_f17">{{Cite web|url=http://www.nasaspaceflight.com/2010/05/axa-launch-h-iia-carrying-akatsuki-ikaros/|title=JAXA launch H-IIA carrying AKATSUKI and IKAROS scrubbed|author=Chris Bergin|date=17 May 2010|accessdate=17 May 2010|publisher=NASASpacflight.com}}</ref> || {{flagicon|Japan}} [[PLANET-C]] (Akatsuki) {{flagicon|Japan}} [[IKAROS]] {{flagicon|Japan}} [[UNITEC-1]] (Shin'en) {{flagicon|Japan}} [[Waseda-SAT2]] {{flagicon|Japan}} [[K-Sat]] (Hayato) {{flagicon|Japan}} [[Negai (satellite)|Negai☆″]]|| {{Success}}
|-
| September 11, 2010 11:17:00<ref>{{cite web |url=http://www.jaxa.jp/press/2010/08/20100804_michibiki_e.html |title=New Launch Day of the First Quasi-Zenith Satellite 'MICHIBIKI' by H-IIA Launch Vehicle No. 18 |publisher=JAXA}}</ref> || F18 || H2A 202 || {{flagicon|Japan}} [[Quasi-Zenith Satellite System|QZS-1]] (Michibiki) || {{Success}}
|-
| September 23, 2011 04:36:50<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/09/japanese-h-2a-launches-new-igs-military-satellite/|title=Japanese H-2A launches with new IGS military satellite |author=Chris Bergin|date=23 September 2011 |publisher= NASASpaceflight.com}}</ref> || F19 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 4 || {{Success}}
|-
| December 12, 2011 01:21:00<ref>{{cite web |url=http://www.nasaspaceflight.com/2011/12/japanese-h-2a-lofts-igs-radar-3-satellite-into-orbit/ |author=Chris Bergin|date=11 December 2011 |publisher= NASASpaceflight.com|title=Japanese H-2A lofts IGS (Radar-3) satellite into orbit}}</ref> || F20 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 3 || {{Success}}
|-
| May 17, 2012 16:39:00 || F21 || H2A 202<ref>{{cite web |url=http://h2a.mhi.co.jp/en/f21/overview/index.html |title=Launch Overview – H-IIA Launch Services Flight No.21 |accessdate=April 15, 2012 |publisher=Mitsubishi Heavy Industries}}</ref> || {{flagicon|Japan}} [[GCOM-W]]1 (Shizuku) {{flagicon|South Korea}} [[KOMPSAT-3]] (Arirang 3) {{flagicon|Japan}} [[SDS-4]] {{flagicon|Japan}} [[HORYU-2]] || {{Success}}
|-
| January 27, 2013 04:40:00 || F22 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 4 {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5V|| {{Success}}
|-
| February 27, 2014 18:37:00 || F23 || H2A 202 || {{flagicon|Japan}} {{flagicon|USA}} [[Global Precipitation Measurement|GPM-Core]] {{flagicon|JPN}} SindaiSat (Ginrei) {{flagicon|JPN}} STARS-II (Gennai) {{flagicon|JPN}} TeikyoSat-3 {{flagicon|JPN}} ITF-1 (Yui) {{flagicon|JPN}} OPUSAT (CosMoz) {{flagicon|JPN}} INVADER {{flagicon|JPN}} KSAT2|| {{Success}}
|-
| May 24, 2014 03:05:14 || F24 || H2A 202 || {{flagicon|Japan}} [[ALOS-2]] (Daichi 2) {{flagicon|JPN}} [[RISING-2]] {{flagicon|JPN}} [[UNIFORM-1]] {{flagicon|JPN}} [[SOCRATES (satellite)|SOCRATES]] {{flagicon|JPN}} SPROUT|| {{Success}}
|-
| October 7, 2014 05:16:00 || F25 || H2A 202 || {{flagicon|Japan}} [[Himawari 8]] || {{Success}}
|-
| December 3, 2014 04:22:04 || F26 || H2A 202 || {{flagicon|Japan}} [[Hayabusa 2]] {{flagicon|Japan}} [[Shin'en 2]] {{flagicon|Japan}} ARTSAT2-DESPATCH {{flagicon|Japan}} [[PROCYON]]|| {{Success}}
|-
| February 1, 2015 01:21:00 || F27 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar Spare|| {{Success}}
|-
| March 26, 2015 01:21:00 || F28 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 5|| {{Success}}
|-
| November 24, 2015 06:50:00 || F29 || H2A 204 || {{flagicon|Canada}} [[Telesat|Telstar 12 Vantage]] ||{{Success}}
|-
| rowspan=2 | February 17, 2016 08:45:00 || rowspan=2 | F30 || H2A 202 || {{flagicon|Japan}} [[ASTRO-H]] (Hitomi) {{flagicon|Japan}} ChubuSat-2 (Kinshachi 2) {{flagicon|Japan}} ChubuSat-3 (Kinshachi 3) {{flagicon|Japan}} Horyu-4 ||{{Success}}
|-
| colspan=3 style="background:linen;" | The Hitomi telescope broke apart shortly after launch.<ref name="clark-20160418">{{cite news |url=http://spaceflightnow.com/2016/04/18/spinning-japanese-astronomy-satellite-may-be-beyond-saving/ |title=Attitude control failures led to break-up of Japanese astronomy satellite |work=Spaceflight Now |first=Stephen |last=Clark |date=18 April 2016 |accessdate=21 April 2016}}</ref>
|-
| November 2, 2016 06:20:00 || F31 || H2A 202 || {{flagicon|Japan}} [[Himawari 9]] ||{{Success}}
|-
| January 24, 2017 07:44:00 || F32 || H2A 204 || {{flagicon|Japan}} [[DSN-2]] (Kirameki 2) || {{Success}}
|-
| March 17, 2017 01:20:00 || F33 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Radar 5 || {{Success}}
|-
| June 1, 2017 00:17:46 || F34 || H2A 202 || {{flagicon|Japan}} [[QZS-2]] (Michibiki 2) || {{Success}}
|-
| August 19, 2017 05:29:00 || F35 || H2A 204 || {{flagicon|Japan}} [[QZS-3]] (Michibiki 3) || {{Success}}
|-
| October 9, 2017 22:01:37 || F36 || H2A 202 || {{flagicon|Japan}} [[QZS-4]] (Michibiki 4) || {{Success}}
|-
| December 23, 2017 01:26:22 || F37 || H2A 202 || {{flagicon|Japan}} [[GCOM-C]] (Shikisai) {{flagicon|Japan}} [[SLATS]] (Tsubame) || {{Success}}
|-
| February 25, 2018 04:34 || F38 || H2A 202 || {{flagicon|Japan}} [[Information Gathering Satellite|IGS]]-Optical 6 || {{Success}}
|-
|}

==See also==
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]

== References ==
'''Notes'''
{{Reflist|30em}}

'''Sources'''
{{Refbegin}}
* {{Cite web|title=Japan Prepares for Crucial Rocket Launch|work=SPACE.com|url=http://www.space.com/missionlaunches/ap_jaxa_h2a_050209.html|accessdate=16 February 2005 }}
* {{Cite web|title=H-IIA Expendable Launch Vehicle|work=SPACEandTECH|url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|accessdate=February 16, 2005|deadurl=yes|archiveurl=https://www.webcitation.org/64qmrxW1D?url=http://www.spaceandtech.com/spacedata/elvs/h2a_sum.shtml|archivedate=January 21, 2012|df=}}
{{Refend}}

==External links==
{{commons category|H-IIA}}
* [http://h2a.mhi.co.jp/en/ H-IIA LAUNCH SERVICES], Mitsubishi Heavy Industries
* [http://www.jaxa.jp/projects/rockets/h2a/index_e.html JAXA H-IIA English page]
* [https://web.archive.org/web/20070321160909/http://www.jaxa.jp/index_e.html JAXA English page]
* [http://www.jaxa.jp/projects/in_progress_e.html JAXA Launch Schedule]
* [http://www.jaxa.jp/about/centers/tnsc/index_e.html Tanegashima Space Center]
* [https://web.archive.org/web/20050404015815/http://visit.jaxa.jp/tanegashima/index_e.html "Tanegashima Space Center"– VISIT JAXA --]
* [https://web.archive.org/web/20041015211458/http://www.astronautix.com/lvs/h2a.htm Encyclopedia Astronautica page]
* [http://spaceflightnow.com/h2a/f6/ Failed Launch, 11-29-2003]
* [http://www.spaceflightnow.com/h2a/f2/020201rocket.html Image]
* [http://www.spaceflightnow.com/h2a/f3/020908rocket.html Launch 2 Image]

{{Mitsubishi Heavy Industries}}
{{Expendable launch systems}}
{{Japanese launch systems}}

{{DEFAULTSORT:H-Iia}}
[[Category:Expendable space launch systems]]
[[Category:Mitsubishi Heavy Industries space launch vehicles]]
[[Category:Vehicles introduced in 2001]]

[[de:H-II#H-IIA]]

RL10

2018-05-15T20:28:23Z

Blastr42: /* OmegA Upper Stage */

{{Use mdy dates|date=April 2017}}
{{Infobox rocket engine
|name =RL10
|image =RL-10 rocket engine (30432256313).jpg
|image_size =250
|caption =An RL10A-4 engine in London's [[Science Museum, London|Science Museum]]
|country_of_origin=[[United States|United States of America]]
|date =
|first_date =1962 (RL10A-1)
|last_date =
|designer = [[Pratt & Whitney]]/[[Marshall Space Flight Center|MSFC]]
|manufacturer = [[Pratt & Whitney Space Propulsion]] [[Pratt & Whitney Rocketdyne]] [[Aerojet Rocketdyne]]
|purpose =[[Upper stage]] engine
|associated =[[Atlas (rocket family)|Atlas]] [[Titan (rocket family)|Titan]] [[Delta IV]] [[Saturn I]]
|successor =
|status =In production
|type =liquid
|oxidiser =[[Liquid oxygen]]
|fuel =[[Liquid hydrogen]]
|mixture_ratio =5.5 or 5.88:1
|cycle =[[Expander cycle]]
|pumps =
|description =
|combustion_chamber=
|nozzle_ratio =84:1 or 280:1

|thrust =
|thrust_at_altitude=
|thrust(Vac) ={{convert|110|kN|abbr=on}}
|thrust(SL) =
|thrust_to_weight=
|chamber_pressure=
|specific_impulse=
|specific_impulse_vacuum={{convert|450|-|465.5|isp}}
|specific_impulse_sea_level=
|total_impulse =
|burn_time =700 seconds
|capacity =

|dimensions =
|length ={{convert|4.14|m|abbr=on}} w/ nozzle extended
|diameter ={{convert|2.13|m|abbr=on}}
|dry_weight ={{convert|277|kg|abbr=on}}

|used_in =[[Centaur (rocket stage)|Centaur]] [[S-IV]] [[Delta Cryogenic Second Stage|DCSS]]

|references =<ref name="EA10B2"/>
|notes =Performance values and dimensions are for RL10B-2.
}}
The '''RL10''' is a [[liquid-fuel rocket|liquid-fuel]] [[cryogenic rocket engine]] used on the [[Centaur (rocket stage)|Centaur]], [[S-IV]], and [[Delta Cryogenic Second Stage]] [[upper stage]]s. Built in the [[United States]] by [[Aerojet Rocketdyne]] (formerly by [[Pratt & Whitney Rocketdyne]]), the RL10 burns [[Cryogenic fuel|cryogenic]] [[liquid hydrogen]] and [[liquid oxygen]] propellants, with each engine producing {{convert|64.7|to(-)|110|kN|sigfig=5|abbr=on}} of [[thrust]] in vacuum depending on the version in use. The RL10 was the first liquid hydrogen rocket engine to be built in the United States, and development of the engine by [[Marshall Space Flight Center]] and [[Pratt & Whitney]] began in the 1950s, with the first flight occurring in 1961. Several versions of the engine have been flown, with two, the RL10A-4-2 and the RL10B-2, still being produced and flown on the [[Atlas V]] and [[Delta IV]].

The engine produces a [[specific impulse]] (''I''sp) of {{convert|373|to(-)|470|isp|abbr=on}} in a vacuum and has a mass ranging from {{convert|131|to(-)|317|kg|abbr=on}} (depending on version). Six RL10A-3 engines were used in the [[S-IV]] second stage of the [[Saturn I]] rocket, one or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets, and one RL10B-2 is used in the upper stage of [[Delta IV]] rockets.

==History==
The RL10 was first tested on the ground in 1959, at [[Pratt & Whitney]]'s Florida Research and Development Center in [[West Palm Beach, Florida]].<ref>Connors, p 319</ref> It was first flown in 1962 in an unsuccessful suborbital test;<ref name="gunter.centaur">{{cite web |title=Centaur |publisher=Gunter's Space Pages |url=http://space.skyrocket.de/doc_stage/centaur.htm}}</ref> the first successful flight took place on November 27, 1963.<ref>{{cite book |last=Sutton |first=George |title=History of liquid propellant rocket engines |publisher=American Institute of Aeronautics and Astronautics |date=2005 |isbn=1-56347-649-5}}</ref><ref>{{cite web |url=http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |title=Renowned Rocket Engine Celebrates 40 Years of Flight |date=November 24, 2003 |publisher=Pratt & Whitney |deadurl=yes |archiveurl=https://web.archive.org/web/20110614033822/http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |archivedate=June 14, 2011 |df=mdy-all}}</ref> For that launch, two RL10A-3 engines powered the [[Centaur (rocket stage)|Centaur]] upper stage of an [[Atlas (rocket family)|Atlas]] launch vehicle. The launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle.<ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1963-047A |title=Atlas Centaur 2 |publisher=NASA |work=[[National Space Science Data Center]]}}</ref> The RL10 was designed for the USAF from the beginning as a throttleable motor for the [[Lunex Project|Lunex]] lunar lander, finally putting this capability to use twenty years later in the [[McDonnell Douglas DC-X|DC-X]] VTOL vehicle.<ref>{{cite web |url=http://www.astronautix.com/articles/lunex.htm |title=Encyclopedia Astronautica—Lunex Project page |work=Encyclopedia Astronautica |first=Mark |last=Wade |deadurl=yes |archiveurl=https://web.archive.org/web/20060831191541/http://www.astronautix.com/articles/lunex.htm |archivedate=August 31, 2006 |df=mdy-all }}</ref>

===Improvements===
The RL10 has been upgraded over the years. One current model, the RL10B-2, powers the Delta IV second stage. It has been significantly modified from the original RL10 to improve performance. Some of the enhancements include an extendable nozzle and electro-mechanical [[gimbal]]ing for reduced weight and increased reliability. Current [[specific impulse]] is {{convert|464|isp}}.

A flaw in the [[brazing]] of an RL10B-2 combustion chamber was identified as the cause of failure for the May 4, 1999, [[Delta III]] launch carrying the Orion-3 [[communications satellite]].<ref>{{cite web |title=Delta 269 (Delta III) Investigation Report |url=http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |publisher=[[Boeing]] |date=August 16, 2000 |archiveurl=https://web.archive.org/web/20010616012841/http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |archivedate=June 16, 2001 |id=MDC 99H0047A}}</ref>

Aerojet Rocketdyne is working toward incorporating [[additive manufacturing]] into the RL10 construction process. The company conducted full-scale, hot-fire tests on an engine with a printed core main injector in March 2016,<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-successfully-tests-complex-3-d-printed-injector-worlds-most-reliable |title=Aerojet Rocketdyne Successfully Tests Complex 3-D Printed Injector in World's Most Reliable Upper Stage Rocket Engine |publisher=Aerojet Rocketdyne |date=March 7, 2016 |access-date=April 20, 2017}}</ref> and on an engine with a printed [[thrust chamber]] assembly in April 2017.<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-achieves-3-d-printing-milestone-successful-testing-full-scale-rl10-copper |title=Aerojet Rocketdyne Achieves 3-D Printing Milestone with Successful Testing of Full-Scale RL10 Copper Thrust Chamber Assembly |publisher=Aerojet Rocketdyne |date=April 3, 2017 |access-date=April 11, 2017}}</ref>

==Applications for the RL10==
Four modified RL10A-5 engines, all of them with the ability to be throttled, were used in the [[McDonnell Douglas DC-X]].<ref name=astro-dcx>{{cite web |url=http://www.astronautix.com/lvs/dcx.htm |title=DCX |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=January 4, 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20121228125150/http://www.astronautix.com/lvs/dcx.htm |archivedate=December 28, 2012 |df=}}</ref>

The [[DIRECT]] version 3.0 proposal to replace [[Ares I]] and [[Ares V]] with a family of rockets sharing a common core stage, recommends the RL10 for the second stage of their proposed J-246 and J-247 launch vehicles.<ref name = "direct_v3_specs">{{cite web |title=Jupiter Launch Vehicle – Technical Performance Summaries |url=http://www.launchcomplexmodels.com/Direct/media.htm |archiveurl=http://www.launchcomplexmodels.com/Direct/documents/Baseball_Cards/ |archivedate=June 8, 2009 |accessdate=July 18, 2009}}</ref> Up to seven RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the [[Ares V]] [[Earth Departure Stage]].

===Common Extensible Cryogenic Engine===
[[Image:Common Extensible Cryogenic Engine.jpg|thumb|The CECE at partial throttle]]

The Common Extensible Cryogenic Engine (CECE) is a testbed to develop RL10 engines that throttle well. NASA has contracted with [[Pratt & Whitney Rocketdyne]] to develop the CECE demonstrator engine.<ref>{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Common Extensible Cryogenic Engine (CECE) |publisher=United Technologies Corporation |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref> In 2007 its operability (with some "chugging") was demonstrated at 11-to-1 throttle ratios.<ref>{{cite web |url=https://science.nasa.gov/headlines/y2007/16jul_cece.htm |title=Throttling Back to the Moon |date=July 16, 2007 |publisher=NASA |deadurl=yes |archiveurl=https://web.archive.org/web/20100402064331/http://science.nasa.gov/headlines/y2007/16jul_cece.htm |archivedate=April 2, 2010 |df=mdy-all }}</ref> In 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature and flow of propellants.<ref>{{cite web |url=http://www.nasa.gov/home/hqnews/2009/jan/HQ_09-005_Cryo_engine_test.html |title=NASA Tests Engine Technology for Landing Astronauts on the Moon |date=January 14, 2009 |publisher=NASA}}</ref>

===Advanced Common Evolved Stage===
{{asof|2009}}, an enhanced version of the RL10 rocket engine was proposed to power the upper-stage versions of the [[Advanced Cryogenic Evolved Stage]] (ACES), a long-duration, low-boiloff extension of existing [[United Launch Alliance|ULA]] [[Centaur (rocket stage)|Centaur]] and [[Delta Cryogenic Second Stage]] (DCSS) technology.<ref name=aiaa20096566>{{cite journal |url=https://info.aiaa.org/tac/SMG/STTC/White%20Papers/DualThrustAxisLander(DTAL)2009.pdf |title=Robust Lunar Exploration Using an Efficient Lunar Lander Derived from Existing Upper Stages |journal=AIAA |first1=Bernard F. |last1=Kutter |first2=Frank |last2=Zegler |first3=Jon |last3=Barr |first4=Tim |last4=Bulk |first5=Brian |last5=Pitchford |date=2009 |ref=AIAA 2009-6566}}</ref> Long-duration ACES technology is explicitly designed to support [[geosynchronous]], [[cislunar]], and [[interplanetary mission|interplanetary]] missions as well as provide in-space [[propellant depot]]s in [[low-Earth orbit|LEO]] or at {{L2}} that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or [[interplanetary mission|interplanetary]] missions. Additional missions could include the provision of the [[delta-v|high-energy]] technical capacity for the cleanup of [[space debris]].<ref name=aiaa20100902>{{cite web |last=Zegler |first=Frank |title=Evolving to a Depot-Based Space Transportation Architecture |url=http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |work=AIAA SPACE 2010 Conference & Exposition |publisher=AIAA |accessdate=January 25, 2011 |author2=Bernard Kutter |date=September 2, 2010 |quote=''ACES design conceptualization has been underway at ULA for many years. It leverages design features of both the Centaur and Delta Cryogenic Second Stage (DCSS) upper stages and intends to supplement and perhaps replace these stages in the future. ...'' |deadurl=yes |archiveurl=https://web.archive.org/web/20111020010301/http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |archivedate=October 20, 2011 |df=mdy-all}}</ref>

===SLS Exploration Upper Stage===
In April 2016 it was reported NASA has chosen to use a design based on four RL10 engines for the [[Exploration Upper Stage]] to be used beginning with the crewed [[Exploration Mission 2|EM-2]] mission of the [[Space Launch System]].<ref>{{cite web |last=Bergin |first=Chris |title=MSFC propose Aerojet Rocketdyne supply EUS engines |url=https://www.nasaspaceflight.com/2016/04/msfc-aerojet-rocketdyne-eus-engines/ |work=[[NASASpaceFlight.com]] |accessdate=April 8, 2016 |date=April 7, 2016}}</ref> In October 2016 NASA confirmed these reports when it announced that the [[Exploration Upper Stage]] would utilize a new variant of the engine identified as the RL10C-3.<ref>{{cite web |title=Proven Engine Packs Big, In-Space Punch for NASA’s SLS Rocket |url=https://www.nasa.gov/exploration/systems/sls/proven-engine-packs-big-in-space-punch-for-nasa-s-sls-rocket.html |publisher=NASA |accessdate=November 22, 2017 |date=October 21, 2016}}</ref>

===OmegA Upper Stage===
In April 2018, Orbital ATK announced it would use two RL10C-5-1 engines for their [[Omega_(rocket)|OmegA]] to power the upper stage.<ref>{{cite web |title=RL-10 Selected for OmegA Rocket |url=http://www.rocket.com/article/rl10-selected-omega%E2%84%A2-rocket |publisher=Aerojet Rocketdyne |accessdate=May 14, 2018 |date=April 16, 2018}}</ref> Blue Origin's BE-3U and Airbus Safran's Vinci were also considered before Aerojet Rocketdyne's engine was selected.

===Vulcan Centaur Upper Stage===
On May 11, 2018 United Launch Alliance (ULA) announced that Aerojet Rocketdyne would be strategic partner with their RL10C-X upper stage engine for ULA’s next-generation Vulcan Centaur rocket following a competitive procurement process.<ref>{{cite web |title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine |url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage |publisher=ULA |accessdate=May 13, 2018 |date=May 11, 2018}}</ref>

==Variants==
{| class="sortable wikitable"
! Version
! Status
! First flight
! Dry mass
! Thrust
! [[Specific impulse|''I''sp (<math>v_\text{e}</math>), vac]]
! Length
! Diameter
! [[Thrust-to-weight ratio|T:W]]
! O:F
! [[Expansion ratio]]
! Chamber pressure
! Burn time
! Associated stage
! Notes
|-
| RL10A-1
| Retired
| 1962
| {{cvt|131|kg}}
| {{cvt|15000|lbf|kN|order=flip}}
| {{cvt|425|isp}}
| {{cvt|1.73|m}}
| {{cvt|1.53|m}}
| 52:1
|
| 40:1
|
| 430 s
| [[Centaur (rocket stage)|Centaur A]]
| Prototype <ref name="EA10A1">{{cite web |url=http://www.astronautix.com/engines/rl10a1.htm |title=RL-10A-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115155200/http://www.astronautix.com/engines/rl10a1.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref><ref name="S2S"/><ref name="GSPAC">{{cite web |url=http://space.skyrocket.de/doc_lau/atlas_centaur.htm |title=Atlas Centaur |publisher=Gunter's Space Page |accessdate=February 29, 2012}}</ref>
|-
| RL10A-3
| Retired
| 1963
| {{cvt|131|kg}}
| {{cvt|65.6|kN}}
| {{cvt|444|isp}}
| {{cvt|2.49|m}}
| {{cvt|1.53|m}}
| 51:1
| 5:1
| 57:1
| {{cvt|32.75|bar}}
| 470 s
| [[Centaur (rocket stage)|Centaur]] B/C/D/E [[S-IV]]
| <ref name="EA10A3">{{cite web |url=http://www.astronautix.com/engines/rl10a3.htm |title=RL-10A-3 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111206225154/http://www.astronautix.com/engines/rl10a3.htm |archivedate=December 6, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4
| Retired
| 1992
| {{cvt|168|kg}}
| {{cvt|92.5|kN}}
| {{cvt|449|isp}}
| {{cvt|2.29|m}}
| {{cvt|1.17|m}}
| 56:1
| 5.5:1
| 84:1
|
| 392 s
| [[Centaur (rocket stage)|Centaur IIA]]
| <ref name="EA10A4">{{cite web |url=http://www.astronautix.com/engines/rl10a4.htm |title=RL-10A-4 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115172045/http://www.astronautix.com/engines/rl10a4.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-1
| Retired
| 2000
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.53|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIA]]
| <ref name="EA10A41">{{cite web |url=http://www.astronautix.com/engines/rl10a41.htm |title=RL-10A-4-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111117134046/http://www.astronautix.com/engines/rl10a41.htm |archivedate=November 17, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-2 {{Clarify|date=May 2016}}
| In production
| 2002
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.17|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIB]] Centaur V1 Centaur V2
| <ref name="EA10A42">{{cite web |url=http://www.astronautix.com/engines/rl10a42.htm |title=RL-10A-4-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120130143126/http://www.astronautix.com/engines/rl10a42.htm |archivedate=January 30, 2012 |df=mdy-all}}</ref><ref name=":0" />
|-
| RL10A-5
| Retired
| 1993
| {{cvt|143|kg}}
| {{cvt|64.7|kN}}
| {{cvt|373|isp}}
| {{cvt|1.07|m}}
| {{cvt|1.02|m}}
| 46:1
| 6:1
| 4:1
|
| 127 s
| [[McDonnell Douglas DC-X|DC-X]]
| <ref name="EA10A5">{{cite web |url=http://www.astronautix.com/engines/rl10a5.htm |title=RL-10A-5 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115141830/http://www.astronautix.com/engines/rl10a5.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10B-2
| In production
| 1998
| {{cvt|277|kg}}
| {{cvt|110|kN}}
| {{cvt|462|isp}}
| {{cvt|4.14|m}}
| {{cvt|2.13|m}}
| 40:1
| 5.88:1
| 280:1
| {{cvt|44.12|bar}}
| 5m: 1,125 s 4m: 700 s
| [[Delta Cryogenic Second Stage]]
| <ref name="EA10B2">{{cite web |url=http://www.astronautix.com/engines/rl10b2.htm |title=RL-10B-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm |archivedate=February 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|title=Delta IV Launch Services User's Guide, June 2013|url=https://www.ulalaunch.com/docs/default-source/rockets/delta-iv-user's-guide.pdf|website=ULA Launch|accessdate=15 March 2018}}</ref>
|-
| RL10B-X
| Cancelled
|
| {{cvt|317|kg}}
| {{cvt|93.4|kN}}
| {{cvt|470|isp}}
|
| {{cvt|1.53|m}}
| 30:1
|
| 250:1
|
| 408 s
| [[Centaur (rocket stage)|Centaur B-X]]
| <ref name="EA10BX">{{cite web |url=http://www.astronautix.com/engines/rl10bx.htm |title=RL-10B-X |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115150728/http://www.astronautix.com/engines/rl10bx.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| CECE
| Demonstrator project
|
| {{cvt|160|kg}}
| {{cvt|15000|lbf|kN|order=flip}}, throttle to 5–10%
| >{{cvt|445|isp}}
| {{cvt|1.53|m}}
|
|
|
|
|
|
|
| <ref name="PWRCECE">{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Commons Extensible Cryogenic Engine |publisher=Pratt & Whitney Rocketdyne |accessdate=February 28, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|url=http://www.rocket.com/common-extensible-cryogenic-engine|title=Common Extensible Cryogenic Engine - Aerojet Rocketdyne|author=|date=|website=www.rocket.com|accessdate=April 8, 2018}}</ref>
|-
| RL10C-1 {{Clarify|date=May 2016}}
| In production
| 2014
| {{cvt|420|lb|order=flip}}
| {{cvt|22890|lbf|kN|order=flip}}
| {{cvt|449.7|isp}}
| {{cvt|2.22|m}}
| {{cvt|1.44|m}}
| 57:1
| 5.5:1
| 130:1
|
| 2000 s
| Centaur SEC
| <ref name="CPS">{{cite web |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015783.pdf |title=Cryogenic Propulsion Stage |publisher=NASA |accessdate=October 11, 2014}}</ref><ref>{{cite web|url=http://forum.nasaspaceflight.com/index.php?topic=34891.0|title=Atlas-V with RL10C powered Centaur|author=|date=|website=forum.nasaspaceflight.com|accessdate=April 8, 2018}}</ref><ref>{{cite web |title=Evolution of Pratt & Whitney's cryogenic rocket engine RL-10 |url=http://b14643.de/Spacerockets/Diverse/P&W_RL10_engine/index.htm |accessdate=February 20, 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20160303141931/http://b14643.de/Spacerockets/Diverse/P%26W_RL10_engine/index.htm |archivedate=March 3, 2016 |df=mdy-all }}</ref><ref name=":0">{{cite web |title=RL10 Engine |url=http://www.rocket.com/rl10-engine |publisher=Aerojet Rocketdyne}}</ref>
|}

==Specifications==

===Original RL10===
[[File:RL-10 rocket engine.jpg|thumb|300px]]
* Thrust (altitude): 15,000 [[Pound-force|lbf]] (66.7 kN)<ref name="S2S">{{cite book |url=https://history.nasa.gov/SP-4206/ch5.htm |title=Stages to Saturn; A Technological History of the Apollo/Saturn Launch Vehicles |chapter=Unconventional Cryogenics: RL-10 and J-2 |publisher=NASA History Office |location=Washington, D.C. |first=Roger E. |last=Bilstein |date=1996 |accessdate=December 2, 2011}}</ref>
* Burn Time: 470 s
* Design: [[Expander cycle]]
* [[Specific impulse]]: {{convert|433|isp}}
* Engine weight—[[dry weight|dry]]: 298 lb (135 kg)
* Height: 68 in (1.73 m)
* Diameter: 39 in (0.99 m)
* Nozzle expansion ratio: 40 to 1
* Propellants: Liquid Oxygen & Liquid Hydrogen
* Propellant flow: 35 lb/s (16 kg/s)
* Contractor: Pratt & Whitney
* Vehicle application: [[Saturn I]] / [[S-IV]] 2nd stage—6-engines
* Vehicle application: [[Centaur (rocket stage)|Centaur]] upper stage—2-engines

===Current design===
[[File:Second stage of a Delta IV Medium rocket.jpg|thumb|Second stage of a Delta IV Medium rocket featuring an RL10B-2 engine]]

; RL10B-2 Specifications
*Thrust (altitude): 24,750 lbf (110.1 kN)<ref name=pwr_rl10b-2.pdf>{{cite web |url=http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |title=RL10B-2 |publisher=[[Pratt & Whitney Rocketdyne]] |date=2009 |accessdate=January 29, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120326211303/http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |archivedate=March 26, 2012 |df=mdy-all }}</ref>
*Design: [[Expander cycle]]<ref name="Sutton1998">{{cite journal |url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA397948 |title=50K expander cycle engine demonstration |journal=AIP Conference Proceedings |first1=A. M. |last1=Sutton |first2=S. D. |last2=Peery |first3=A. B. |last3=Minick |volume=420 |pages=1062–1065 |date=January 1998 |doi=10.1063/1.54719}}</ref>
*[[Specific impulse]]: {{convert|464|isp}}<ref name=pwr_rl10b-2.pdf />
*Engine weight - dry: 610 lb (277 kg)<ref name=pwr_rl10b-2.pdf />
*Height: 163 in (4.14 m)<ref name=pwr_rl10b-2.pdf />
*Diameter: 87 in (2.21 m)<ref name=pwr_rl10b-2.pdf />
*Expansion ratio: 280 to 1
*Mixture ratio: 5.88 to 1 <ref name=pwr_rl10b-2.pdf />
*Propellants: [[Liquid oxygen]] & [[liquid hydrogen]]<ref name=pwr_rl10b-2.pdf />
*Propellant flow: Oxidizer 41.42 lb/s (20.6 kg/s), fuel 7.72 lb/s (3.5 kg/s)<ref name=pwr_rl10b-2.pdf />
*Contractor: Pratt & Whitney
*Vehicle application: [[Delta III]], Delta IV second stage (1 engine)

; RL10A-4-2
The other current model, the RL10A-4-2, is the engine used on [[Centaur (rocket stage)|Centaur]] upper stage for [[Atlas V]].<ref name=pwr_rl10b-2.pdf />

==Possible successor==
In 2012 NASA joined with the US Air Force (USAF) to study next-generation upper stage propulsion, formalizing the agencies joint interests in a new upper stage engine to replace the Aerojet Rocketdyne RL10.
{{quote|"We know the list price on an RL10. If you look at cost over time, a very large portion of the unit cost of the EELVs is attributable to the propulsion systems, and the RL10 is a very old engine, and there's a lot of craftwork associated with its manufacture. ... That's what this study will figure out, is it worthwhile to build an RL10 replacement?"|author=Dale Thomas, Associated Director Technical, Marshall Space Flight Center<ref name=FG2012/>}}

From the study, NASA hopes to find a less expensive RL10-class engine for a third stage of the [[Space Launch System]] (SLS).<ref name=FG2012/><ref name=NASA-2012-04/>

USAF hopes to replace the Rocketdyne RL10 engines used on the upper stage of both the Lockheed Martin Atlas V and the Boeing Delta IV, known as [[Evolved Expendable Launch Vehicle]]s (EELV), that are the primary methods of putting US government satellites into space.<ref name=FG2012>{{cite web |last=Roseberg |first=Zach |title=NASA, US Air Force to study joint rocket engine |url=http://www.flightglobal.com/news/articles/nasa-us-air-force-to-study-joint-rocket-engine-370660/ |publisher=Flight Global |accessdate=June 1, 2012 |date=April 12, 2012}}</ref> This relates to the requirements study of the [[Affordable Upper Stage Engine Program]] (AUSEP) liquid rocket engine for use on upper stages of medium- and heavy-class launch vehicles, including the Evolved Expendable Launch Vehicle (EELV) family of launch vehicles.<ref name=NASA-2012-04>{{cite web |url=https://www.nasa.gov/centers/marshall/news/news/releases/2012/12-040.html |title=NASA Partners With U.S. Air Force to Study Common Rocket Propulsion Challenges |publisher=NASA |first=Kimberly |last=Newton |date=April 12, 2012}}</ref>

==Engines on display==
* An RL10 is on display at the [[New England Air Museum]], [[Windsor Locks, Connecticut]]<ref>{{cite web |url=http://neam.org/index.php?option=com_content&view=article&id=1112 |title=Pratt & Whitney RL10A-1 Rocket Engine |work=New England Air Museum |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], [[Chicago]], [[Illinois]]<ref name="histspace">{{cite web |url=http://historicspacecraft.com/rocket_engines.html |title=Photos of Rocket Engines |work=Historic Spacecraft |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[U.S. Space & Rocket Center]], [[Huntsville, Alabama]]<ref name="histspace"/>
* An RL10 is on display at [[Southern University]], [[Baton Rouge, Louisiana]]<ref>{{cite press release |url=http://www.prnewswire.com/news-releases/pratt--whitney-rocketdyne-donates-model-of-legendary-rl10-rocket-engine-to-southern-university-55982567.html |title=Pratt & Whitney Rocketdyne Donates Model of Legendary Rl10 Rocket Engine to Southern University |agency=PR Newswire |publisher=Pratt & Whitney Rocketdyne |first1=Nancy |last1=Colaguori |first2=Bryan |last2=Kidder |date=November 3, 2006 |accessdate=April 26, 2014}}</ref>
* Two RL10 engines are on display at [[US Space Walk of Fame]], [[Titusville, Florida]]<ref>{{cite web|url=https://www.facebook.com/SpaceWalkOfFame/photos/pcb.10152534325180820/10152534320660820/?type=1&theater|title=American Space Museum & Space Walk of Fame|author=|date=|website=www.facebook.com|accessdate=April 8, 2018}}</ref>
* An RL10 is on display in the Aerospace Engineering Department, Davis Hall at [[Auburn University]].{{cn|date=April 2017}}
* An RL10A-4 is on display at the Science Museum in London, UK.

==See also==
*[[Spacecraft propulsion]]
*[[RL60]]
*[[RD-0146]]
*[[XCOR Aerospace#ULA liquid hydrogen large engine development project|XCOR/ULA aluminum alloy nozzle engine]], under development in 2011

==References==
{{Reflist|30em}}

==Bibliography==
* {{cite book |last=Connors |first=Jack |title=The Engines of Pratt & Whitney: A Technical History |publisher=[[American Institute of Aeronautics and Astronautics]] |location=Reston. Virginia |date=2010 |isbn=978-1-60086-711-8 |url=}}

==External links==
{{Commons category|RL10 (rocket engine)|RL10}}
*[https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm RL10B-2 at Astronautix]
*[http://www.spaceflightnow.com/news/n0708/16rl10valve/ Spaceflight Now article]
*[http://www.spaceflightnow.com/news/n0901/26altair/ Spaceflight Now article]

{{Rocket engines}}
{{Atlas rockets}}
{{Thor and Delta rockets}}

[[Category:Rocket engines using hydrogen propellant]]
[[Category:North American Aviation]]
[[Category:Rocket engines using the expander cycle]]

RL10

2018-05-15T20:27:59Z

Blastr42: /* OmegA Upper Stage */

{{Use mdy dates|date=April 2017}}
{{Infobox rocket engine
|name =RL10
|image =RL-10 rocket engine (30432256313).jpg
|image_size =250
|caption =An RL10A-4 engine in London's [[Science Museum, London|Science Museum]]
|country_of_origin=[[United States|United States of America]]
|date =
|first_date =1962 (RL10A-1)
|last_date =
|designer = [[Pratt & Whitney]]/[[Marshall Space Flight Center|MSFC]]
|manufacturer = [[Pratt & Whitney Space Propulsion]] [[Pratt & Whitney Rocketdyne]] [[Aerojet Rocketdyne]]
|purpose =[[Upper stage]] engine
|associated =[[Atlas (rocket family)|Atlas]] [[Titan (rocket family)|Titan]] [[Delta IV]] [[Saturn I]]
|successor =
|status =In production
|type =liquid
|oxidiser =[[Liquid oxygen]]
|fuel =[[Liquid hydrogen]]
|mixture_ratio =5.5 or 5.88:1
|cycle =[[Expander cycle]]
|pumps =
|description =
|combustion_chamber=
|nozzle_ratio =84:1 or 280:1

|thrust =
|thrust_at_altitude=
|thrust(Vac) ={{convert|110|kN|abbr=on}}
|thrust(SL) =
|thrust_to_weight=
|chamber_pressure=
|specific_impulse=
|specific_impulse_vacuum={{convert|450|-|465.5|isp}}
|specific_impulse_sea_level=
|total_impulse =
|burn_time =700 seconds
|capacity =

|dimensions =
|length ={{convert|4.14|m|abbr=on}} w/ nozzle extended
|diameter ={{convert|2.13|m|abbr=on}}
|dry_weight ={{convert|277|kg|abbr=on}}

|used_in =[[Centaur (rocket stage)|Centaur]] [[S-IV]] [[Delta Cryogenic Second Stage|DCSS]]

|references =<ref name="EA10B2"/>
|notes =Performance values and dimensions are for RL10B-2.
}}
The '''RL10''' is a [[liquid-fuel rocket|liquid-fuel]] [[cryogenic rocket engine]] used on the [[Centaur (rocket stage)|Centaur]], [[S-IV]], and [[Delta Cryogenic Second Stage]] [[upper stage]]s. Built in the [[United States]] by [[Aerojet Rocketdyne]] (formerly by [[Pratt & Whitney Rocketdyne]]), the RL10 burns [[Cryogenic fuel|cryogenic]] [[liquid hydrogen]] and [[liquid oxygen]] propellants, with each engine producing {{convert|64.7|to(-)|110|kN|sigfig=5|abbr=on}} of [[thrust]] in vacuum depending on the version in use. The RL10 was the first liquid hydrogen rocket engine to be built in the United States, and development of the engine by [[Marshall Space Flight Center]] and [[Pratt & Whitney]] began in the 1950s, with the first flight occurring in 1961. Several versions of the engine have been flown, with two, the RL10A-4-2 and the RL10B-2, still being produced and flown on the [[Atlas V]] and [[Delta IV]].

The engine produces a [[specific impulse]] (''I''sp) of {{convert|373|to(-)|470|isp|abbr=on}} in a vacuum and has a mass ranging from {{convert|131|to(-)|317|kg|abbr=on}} (depending on version). Six RL10A-3 engines were used in the [[S-IV]] second stage of the [[Saturn I]] rocket, one or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets, and one RL10B-2 is used in the upper stage of [[Delta IV]] rockets.

==History==
The RL10 was first tested on the ground in 1959, at [[Pratt & Whitney]]'s Florida Research and Development Center in [[West Palm Beach, Florida]].<ref>Connors, p 319</ref> It was first flown in 1962 in an unsuccessful suborbital test;<ref name="gunter.centaur">{{cite web |title=Centaur |publisher=Gunter's Space Pages |url=http://space.skyrocket.de/doc_stage/centaur.htm}}</ref> the first successful flight took place on November 27, 1963.<ref>{{cite book |last=Sutton |first=George |title=History of liquid propellant rocket engines |publisher=American Institute of Aeronautics and Astronautics |date=2005 |isbn=1-56347-649-5}}</ref><ref>{{cite web |url=http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |title=Renowned Rocket Engine Celebrates 40 Years of Flight |date=November 24, 2003 |publisher=Pratt & Whitney |deadurl=yes |archiveurl=https://web.archive.org/web/20110614033822/http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |archivedate=June 14, 2011 |df=mdy-all}}</ref> For that launch, two RL10A-3 engines powered the [[Centaur (rocket stage)|Centaur]] upper stage of an [[Atlas (rocket family)|Atlas]] launch vehicle. The launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle.<ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1963-047A |title=Atlas Centaur 2 |publisher=NASA |work=[[National Space Science Data Center]]}}</ref> The RL10 was designed for the USAF from the beginning as a throttleable motor for the [[Lunex Project|Lunex]] lunar lander, finally putting this capability to use twenty years later in the [[McDonnell Douglas DC-X|DC-X]] VTOL vehicle.<ref>{{cite web |url=http://www.astronautix.com/articles/lunex.htm |title=Encyclopedia Astronautica—Lunex Project page |work=Encyclopedia Astronautica |first=Mark |last=Wade |deadurl=yes |archiveurl=https://web.archive.org/web/20060831191541/http://www.astronautix.com/articles/lunex.htm |archivedate=August 31, 2006 |df=mdy-all }}</ref>

===Improvements===
The RL10 has been upgraded over the years. One current model, the RL10B-2, powers the Delta IV second stage. It has been significantly modified from the original RL10 to improve performance. Some of the enhancements include an extendable nozzle and electro-mechanical [[gimbal]]ing for reduced weight and increased reliability. Current [[specific impulse]] is {{convert|464|isp}}.

A flaw in the [[brazing]] of an RL10B-2 combustion chamber was identified as the cause of failure for the May 4, 1999, [[Delta III]] launch carrying the Orion-3 [[communications satellite]].<ref>{{cite web |title=Delta 269 (Delta III) Investigation Report |url=http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |publisher=[[Boeing]] |date=August 16, 2000 |archiveurl=https://web.archive.org/web/20010616012841/http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |archivedate=June 16, 2001 |id=MDC 99H0047A}}</ref>

Aerojet Rocketdyne is working toward incorporating [[additive manufacturing]] into the RL10 construction process. The company conducted full-scale, hot-fire tests on an engine with a printed core main injector in March 2016,<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-successfully-tests-complex-3-d-printed-injector-worlds-most-reliable |title=Aerojet Rocketdyne Successfully Tests Complex 3-D Printed Injector in World's Most Reliable Upper Stage Rocket Engine |publisher=Aerojet Rocketdyne |date=March 7, 2016 |access-date=April 20, 2017}}</ref> and on an engine with a printed [[thrust chamber]] assembly in April 2017.<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-achieves-3-d-printing-milestone-successful-testing-full-scale-rl10-copper |title=Aerojet Rocketdyne Achieves 3-D Printing Milestone with Successful Testing of Full-Scale RL10 Copper Thrust Chamber Assembly |publisher=Aerojet Rocketdyne |date=April 3, 2017 |access-date=April 11, 2017}}</ref>

==Applications for the RL10==
Four modified RL10A-5 engines, all of them with the ability to be throttled, were used in the [[McDonnell Douglas DC-X]].<ref name=astro-dcx>{{cite web |url=http://www.astronautix.com/lvs/dcx.htm |title=DCX |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=January 4, 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20121228125150/http://www.astronautix.com/lvs/dcx.htm |archivedate=December 28, 2012 |df=}}</ref>

The [[DIRECT]] version 3.0 proposal to replace [[Ares I]] and [[Ares V]] with a family of rockets sharing a common core stage, recommends the RL10 for the second stage of their proposed J-246 and J-247 launch vehicles.<ref name = "direct_v3_specs">{{cite web |title=Jupiter Launch Vehicle – Technical Performance Summaries |url=http://www.launchcomplexmodels.com/Direct/media.htm |archiveurl=http://www.launchcomplexmodels.com/Direct/documents/Baseball_Cards/ |archivedate=June 8, 2009 |accessdate=July 18, 2009}}</ref> Up to seven RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the [[Ares V]] [[Earth Departure Stage]].

===Common Extensible Cryogenic Engine===
[[Image:Common Extensible Cryogenic Engine.jpg|thumb|The CECE at partial throttle]]

The Common Extensible Cryogenic Engine (CECE) is a testbed to develop RL10 engines that throttle well. NASA has contracted with [[Pratt & Whitney Rocketdyne]] to develop the CECE demonstrator engine.<ref>{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Common Extensible Cryogenic Engine (CECE) |publisher=United Technologies Corporation |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref> In 2007 its operability (with some "chugging") was demonstrated at 11-to-1 throttle ratios.<ref>{{cite web |url=https://science.nasa.gov/headlines/y2007/16jul_cece.htm |title=Throttling Back to the Moon |date=July 16, 2007 |publisher=NASA |deadurl=yes |archiveurl=https://web.archive.org/web/20100402064331/http://science.nasa.gov/headlines/y2007/16jul_cece.htm |archivedate=April 2, 2010 |df=mdy-all }}</ref> In 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature and flow of propellants.<ref>{{cite web |url=http://www.nasa.gov/home/hqnews/2009/jan/HQ_09-005_Cryo_engine_test.html |title=NASA Tests Engine Technology for Landing Astronauts on the Moon |date=January 14, 2009 |publisher=NASA}}</ref>

===Advanced Common Evolved Stage===
{{asof|2009}}, an enhanced version of the RL10 rocket engine was proposed to power the upper-stage versions of the [[Advanced Cryogenic Evolved Stage]] (ACES), a long-duration, low-boiloff extension of existing [[United Launch Alliance|ULA]] [[Centaur (rocket stage)|Centaur]] and [[Delta Cryogenic Second Stage]] (DCSS) technology.<ref name=aiaa20096566>{{cite journal |url=https://info.aiaa.org/tac/SMG/STTC/White%20Papers/DualThrustAxisLander(DTAL)2009.pdf |title=Robust Lunar Exploration Using an Efficient Lunar Lander Derived from Existing Upper Stages |journal=AIAA |first1=Bernard F. |last1=Kutter |first2=Frank |last2=Zegler |first3=Jon |last3=Barr |first4=Tim |last4=Bulk |first5=Brian |last5=Pitchford |date=2009 |ref=AIAA 2009-6566}}</ref> Long-duration ACES technology is explicitly designed to support [[geosynchronous]], [[cislunar]], and [[interplanetary mission|interplanetary]] missions as well as provide in-space [[propellant depot]]s in [[low-Earth orbit|LEO]] or at {{L2}} that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or [[interplanetary mission|interplanetary]] missions. Additional missions could include the provision of the [[delta-v|high-energy]] technical capacity for the cleanup of [[space debris]].<ref name=aiaa20100902>{{cite web |last=Zegler |first=Frank |title=Evolving to a Depot-Based Space Transportation Architecture |url=http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |work=AIAA SPACE 2010 Conference & Exposition |publisher=AIAA |accessdate=January 25, 2011 |author2=Bernard Kutter |date=September 2, 2010 |quote=''ACES design conceptualization has been underway at ULA for many years. It leverages design features of both the Centaur and Delta Cryogenic Second Stage (DCSS) upper stages and intends to supplement and perhaps replace these stages in the future. ...'' |deadurl=yes |archiveurl=https://web.archive.org/web/20111020010301/http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |archivedate=October 20, 2011 |df=mdy-all}}</ref>

===SLS Exploration Upper Stage===
In April 2016 it was reported NASA has chosen to use a design based on four RL10 engines for the [[Exploration Upper Stage]] to be used beginning with the crewed [[Exploration Mission 2|EM-2]] mission of the [[Space Launch System]].<ref>{{cite web |last=Bergin |first=Chris |title=MSFC propose Aerojet Rocketdyne supply EUS engines |url=https://www.nasaspaceflight.com/2016/04/msfc-aerojet-rocketdyne-eus-engines/ |work=[[NASASpaceFlight.com]] |accessdate=April 8, 2016 |date=April 7, 2016}}</ref> In October 2016 NASA confirmed these reports when it announced that the [[Exploration Upper Stage]] would utilize a new variant of the engine identified as the RL10C-3.<ref>{{cite web |title=Proven Engine Packs Big, In-Space Punch for NASA’s SLS Rocket |url=https://www.nasa.gov/exploration/systems/sls/proven-engine-packs-big-in-space-punch-for-nasa-s-sls-rocket.html |publisher=NASA |accessdate=November 22, 2017 |date=October 21, 2016}}</ref>

===OmegA Upper Stage===
In April 2018, Orbital ATK announced it would use two RL10C-5-1 engines for their [[Omega_(rocket)|OmegA]] to power the upper stage.<ref>{{cite web |title=RL-10 Selected for OmegA Rocket |url=http://www.rocket.com/article/rl10-selected-omega%E2%84%A2-rocket |publisher=Aerojet Rocketdyne |accessdate=May 14, 2018 |date=April 16, 2018}}</ref> Blue Origin's BE-3U and Airbus Safran's Vinci were also considered before the Aerojet Rocketdyne's engine was selected.

===Vulcan Centaur Upper Stage===
On May 11, 2018 United Launch Alliance (ULA) announced that Aerojet Rocketdyne would be strategic partner with their RL10C-X upper stage engine for ULA’s next-generation Vulcan Centaur rocket following a competitive procurement process.<ref>{{cite web |title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine |url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage |publisher=ULA |accessdate=May 13, 2018 |date=May 11, 2018}}</ref>

==Variants==
{| class="sortable wikitable"
! Version
! Status
! First flight
! Dry mass
! Thrust
! [[Specific impulse|''I''sp (<math>v_\text{e}</math>), vac]]
! Length
! Diameter
! [[Thrust-to-weight ratio|T:W]]
! O:F
! [[Expansion ratio]]
! Chamber pressure
! Burn time
! Associated stage
! Notes
|-
| RL10A-1
| Retired
| 1962
| {{cvt|131|kg}}
| {{cvt|15000|lbf|kN|order=flip}}
| {{cvt|425|isp}}
| {{cvt|1.73|m}}
| {{cvt|1.53|m}}
| 52:1
|
| 40:1
|
| 430 s
| [[Centaur (rocket stage)|Centaur A]]
| Prototype <ref name="EA10A1">{{cite web |url=http://www.astronautix.com/engines/rl10a1.htm |title=RL-10A-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115155200/http://www.astronautix.com/engines/rl10a1.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref><ref name="S2S"/><ref name="GSPAC">{{cite web |url=http://space.skyrocket.de/doc_lau/atlas_centaur.htm |title=Atlas Centaur |publisher=Gunter's Space Page |accessdate=February 29, 2012}}</ref>
|-
| RL10A-3
| Retired
| 1963
| {{cvt|131|kg}}
| {{cvt|65.6|kN}}
| {{cvt|444|isp}}
| {{cvt|2.49|m}}
| {{cvt|1.53|m}}
| 51:1
| 5:1
| 57:1
| {{cvt|32.75|bar}}
| 470 s
| [[Centaur (rocket stage)|Centaur]] B/C/D/E [[S-IV]]
| <ref name="EA10A3">{{cite web |url=http://www.astronautix.com/engines/rl10a3.htm |title=RL-10A-3 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111206225154/http://www.astronautix.com/engines/rl10a3.htm |archivedate=December 6, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4
| Retired
| 1992
| {{cvt|168|kg}}
| {{cvt|92.5|kN}}
| {{cvt|449|isp}}
| {{cvt|2.29|m}}
| {{cvt|1.17|m}}
| 56:1
| 5.5:1
| 84:1
|
| 392 s
| [[Centaur (rocket stage)|Centaur IIA]]
| <ref name="EA10A4">{{cite web |url=http://www.astronautix.com/engines/rl10a4.htm |title=RL-10A-4 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115172045/http://www.astronautix.com/engines/rl10a4.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-1
| Retired
| 2000
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.53|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIA]]
| <ref name="EA10A41">{{cite web |url=http://www.astronautix.com/engines/rl10a41.htm |title=RL-10A-4-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111117134046/http://www.astronautix.com/engines/rl10a41.htm |archivedate=November 17, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-2 {{Clarify|date=May 2016}}
| In production
| 2002
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.17|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIB]] Centaur V1 Centaur V2
| <ref name="EA10A42">{{cite web |url=http://www.astronautix.com/engines/rl10a42.htm |title=RL-10A-4-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120130143126/http://www.astronautix.com/engines/rl10a42.htm |archivedate=January 30, 2012 |df=mdy-all}}</ref><ref name=":0" />
|-
| RL10A-5
| Retired
| 1993
| {{cvt|143|kg}}
| {{cvt|64.7|kN}}
| {{cvt|373|isp}}
| {{cvt|1.07|m}}
| {{cvt|1.02|m}}
| 46:1
| 6:1
| 4:1
|
| 127 s
| [[McDonnell Douglas DC-X|DC-X]]
| <ref name="EA10A5">{{cite web |url=http://www.astronautix.com/engines/rl10a5.htm |title=RL-10A-5 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115141830/http://www.astronautix.com/engines/rl10a5.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10B-2
| In production
| 1998
| {{cvt|277|kg}}
| {{cvt|110|kN}}
| {{cvt|462|isp}}
| {{cvt|4.14|m}}
| {{cvt|2.13|m}}
| 40:1
| 5.88:1
| 280:1
| {{cvt|44.12|bar}}
| 5m: 1,125 s 4m: 700 s
| [[Delta Cryogenic Second Stage]]
| <ref name="EA10B2">{{cite web |url=http://www.astronautix.com/engines/rl10b2.htm |title=RL-10B-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm |archivedate=February 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|title=Delta IV Launch Services User's Guide, June 2013|url=https://www.ulalaunch.com/docs/default-source/rockets/delta-iv-user's-guide.pdf|website=ULA Launch|accessdate=15 March 2018}}</ref>
|-
| RL10B-X
| Cancelled
|
| {{cvt|317|kg}}
| {{cvt|93.4|kN}}
| {{cvt|470|isp}}
|
| {{cvt|1.53|m}}
| 30:1
|
| 250:1
|
| 408 s
| [[Centaur (rocket stage)|Centaur B-X]]
| <ref name="EA10BX">{{cite web |url=http://www.astronautix.com/engines/rl10bx.htm |title=RL-10B-X |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115150728/http://www.astronautix.com/engines/rl10bx.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| CECE
| Demonstrator project
|
| {{cvt|160|kg}}
| {{cvt|15000|lbf|kN|order=flip}}, throttle to 5–10%
| >{{cvt|445|isp}}
| {{cvt|1.53|m}}
|
|
|
|
|
|
|
| <ref name="PWRCECE">{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Commons Extensible Cryogenic Engine |publisher=Pratt & Whitney Rocketdyne |accessdate=February 28, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|url=http://www.rocket.com/common-extensible-cryogenic-engine|title=Common Extensible Cryogenic Engine - Aerojet Rocketdyne|author=|date=|website=www.rocket.com|accessdate=April 8, 2018}}</ref>
|-
| RL10C-1 {{Clarify|date=May 2016}}
| In production
| 2014
| {{cvt|420|lb|order=flip}}
| {{cvt|22890|lbf|kN|order=flip}}
| {{cvt|449.7|isp}}
| {{cvt|2.22|m}}
| {{cvt|1.44|m}}
| 57:1
| 5.5:1
| 130:1
|
| 2000 s
| Centaur SEC
| <ref name="CPS">{{cite web |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015783.pdf |title=Cryogenic Propulsion Stage |publisher=NASA |accessdate=October 11, 2014}}</ref><ref>{{cite web|url=http://forum.nasaspaceflight.com/index.php?topic=34891.0|title=Atlas-V with RL10C powered Centaur|author=|date=|website=forum.nasaspaceflight.com|accessdate=April 8, 2018}}</ref><ref>{{cite web |title=Evolution of Pratt & Whitney's cryogenic rocket engine RL-10 |url=http://b14643.de/Spacerockets/Diverse/P&W_RL10_engine/index.htm |accessdate=February 20, 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20160303141931/http://b14643.de/Spacerockets/Diverse/P%26W_RL10_engine/index.htm |archivedate=March 3, 2016 |df=mdy-all }}</ref><ref name=":0">{{cite web |title=RL10 Engine |url=http://www.rocket.com/rl10-engine |publisher=Aerojet Rocketdyne}}</ref>
|}

==Specifications==

===Original RL10===
[[File:RL-10 rocket engine.jpg|thumb|300px]]
* Thrust (altitude): 15,000 [[Pound-force|lbf]] (66.7 kN)<ref name="S2S">{{cite book |url=https://history.nasa.gov/SP-4206/ch5.htm |title=Stages to Saturn; A Technological History of the Apollo/Saturn Launch Vehicles |chapter=Unconventional Cryogenics: RL-10 and J-2 |publisher=NASA History Office |location=Washington, D.C. |first=Roger E. |last=Bilstein |date=1996 |accessdate=December 2, 2011}}</ref>
* Burn Time: 470 s
* Design: [[Expander cycle]]
* [[Specific impulse]]: {{convert|433|isp}}
* Engine weight—[[dry weight|dry]]: 298 lb (135 kg)
* Height: 68 in (1.73 m)
* Diameter: 39 in (0.99 m)
* Nozzle expansion ratio: 40 to 1
* Propellants: Liquid Oxygen & Liquid Hydrogen
* Propellant flow: 35 lb/s (16 kg/s)
* Contractor: Pratt & Whitney
* Vehicle application: [[Saturn I]] / [[S-IV]] 2nd stage—6-engines
* Vehicle application: [[Centaur (rocket stage)|Centaur]] upper stage—2-engines

===Current design===
[[File:Second stage of a Delta IV Medium rocket.jpg|thumb|Second stage of a Delta IV Medium rocket featuring an RL10B-2 engine]]

; RL10B-2 Specifications
*Thrust (altitude): 24,750 lbf (110.1 kN)<ref name=pwr_rl10b-2.pdf>{{cite web |url=http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |title=RL10B-2 |publisher=[[Pratt & Whitney Rocketdyne]] |date=2009 |accessdate=January 29, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120326211303/http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |archivedate=March 26, 2012 |df=mdy-all }}</ref>
*Design: [[Expander cycle]]<ref name="Sutton1998">{{cite journal |url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA397948 |title=50K expander cycle engine demonstration |journal=AIP Conference Proceedings |first1=A. M. |last1=Sutton |first2=S. D. |last2=Peery |first3=A. B. |last3=Minick |volume=420 |pages=1062–1065 |date=January 1998 |doi=10.1063/1.54719}}</ref>
*[[Specific impulse]]: {{convert|464|isp}}<ref name=pwr_rl10b-2.pdf />
*Engine weight - dry: 610 lb (277 kg)<ref name=pwr_rl10b-2.pdf />
*Height: 163 in (4.14 m)<ref name=pwr_rl10b-2.pdf />
*Diameter: 87 in (2.21 m)<ref name=pwr_rl10b-2.pdf />
*Expansion ratio: 280 to 1
*Mixture ratio: 5.88 to 1 <ref name=pwr_rl10b-2.pdf />
*Propellants: [[Liquid oxygen]] & [[liquid hydrogen]]<ref name=pwr_rl10b-2.pdf />
*Propellant flow: Oxidizer 41.42 lb/s (20.6 kg/s), fuel 7.72 lb/s (3.5 kg/s)<ref name=pwr_rl10b-2.pdf />
*Contractor: Pratt & Whitney
*Vehicle application: [[Delta III]], Delta IV second stage (1 engine)

; RL10A-4-2
The other current model, the RL10A-4-2, is the engine used on [[Centaur (rocket stage)|Centaur]] upper stage for [[Atlas V]].<ref name=pwr_rl10b-2.pdf />

==Possible successor==
In 2012 NASA joined with the US Air Force (USAF) to study next-generation upper stage propulsion, formalizing the agencies joint interests in a new upper stage engine to replace the Aerojet Rocketdyne RL10.
{{quote|"We know the list price on an RL10. If you look at cost over time, a very large portion of the unit cost of the EELVs is attributable to the propulsion systems, and the RL10 is a very old engine, and there's a lot of craftwork associated with its manufacture. ... That's what this study will figure out, is it worthwhile to build an RL10 replacement?"|author=Dale Thomas, Associated Director Technical, Marshall Space Flight Center<ref name=FG2012/>}}

From the study, NASA hopes to find a less expensive RL10-class engine for a third stage of the [[Space Launch System]] (SLS).<ref name=FG2012/><ref name=NASA-2012-04/>

USAF hopes to replace the Rocketdyne RL10 engines used on the upper stage of both the Lockheed Martin Atlas V and the Boeing Delta IV, known as [[Evolved Expendable Launch Vehicle]]s (EELV), that are the primary methods of putting US government satellites into space.<ref name=FG2012>{{cite web |last=Roseberg |first=Zach |title=NASA, US Air Force to study joint rocket engine |url=http://www.flightglobal.com/news/articles/nasa-us-air-force-to-study-joint-rocket-engine-370660/ |publisher=Flight Global |accessdate=June 1, 2012 |date=April 12, 2012}}</ref> This relates to the requirements study of the [[Affordable Upper Stage Engine Program]] (AUSEP) liquid rocket engine for use on upper stages of medium- and heavy-class launch vehicles, including the Evolved Expendable Launch Vehicle (EELV) family of launch vehicles.<ref name=NASA-2012-04>{{cite web |url=https://www.nasa.gov/centers/marshall/news/news/releases/2012/12-040.html |title=NASA Partners With U.S. Air Force to Study Common Rocket Propulsion Challenges |publisher=NASA |first=Kimberly |last=Newton |date=April 12, 2012}}</ref>

==Engines on display==
* An RL10 is on display at the [[New England Air Museum]], [[Windsor Locks, Connecticut]]<ref>{{cite web |url=http://neam.org/index.php?option=com_content&view=article&id=1112 |title=Pratt & Whitney RL10A-1 Rocket Engine |work=New England Air Museum |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], [[Chicago]], [[Illinois]]<ref name="histspace">{{cite web |url=http://historicspacecraft.com/rocket_engines.html |title=Photos of Rocket Engines |work=Historic Spacecraft |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[U.S. Space & Rocket Center]], [[Huntsville, Alabama]]<ref name="histspace"/>
* An RL10 is on display at [[Southern University]], [[Baton Rouge, Louisiana]]<ref>{{cite press release |url=http://www.prnewswire.com/news-releases/pratt--whitney-rocketdyne-donates-model-of-legendary-rl10-rocket-engine-to-southern-university-55982567.html |title=Pratt & Whitney Rocketdyne Donates Model of Legendary Rl10 Rocket Engine to Southern University |agency=PR Newswire |publisher=Pratt & Whitney Rocketdyne |first1=Nancy |last1=Colaguori |first2=Bryan |last2=Kidder |date=November 3, 2006 |accessdate=April 26, 2014}}</ref>
* Two RL10 engines are on display at [[US Space Walk of Fame]], [[Titusville, Florida]]<ref>{{cite web|url=https://www.facebook.com/SpaceWalkOfFame/photos/pcb.10152534325180820/10152534320660820/?type=1&theater|title=American Space Museum & Space Walk of Fame|author=|date=|website=www.facebook.com|accessdate=April 8, 2018}}</ref>
* An RL10 is on display in the Aerospace Engineering Department, Davis Hall at [[Auburn University]].{{cn|date=April 2017}}
* An RL10A-4 is on display at the Science Museum in London, UK.

==See also==
*[[Spacecraft propulsion]]
*[[RL60]]
*[[RD-0146]]
*[[XCOR Aerospace#ULA liquid hydrogen large engine development project|XCOR/ULA aluminum alloy nozzle engine]], under development in 2011

==References==
{{Reflist|30em}}

==Bibliography==
* {{cite book |last=Connors |first=Jack |title=The Engines of Pratt & Whitney: A Technical History |publisher=[[American Institute of Aeronautics and Astronautics]] |location=Reston. Virginia |date=2010 |isbn=978-1-60086-711-8 |url=}}

==External links==
{{Commons category|RL10 (rocket engine)|RL10}}
*[https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm RL10B-2 at Astronautix]
*[http://www.spaceflightnow.com/news/n0708/16rl10valve/ Spaceflight Now article]
*[http://www.spaceflightnow.com/news/n0901/26altair/ Spaceflight Now article]

{{Rocket engines}}
{{Atlas rockets}}
{{Thor and Delta rockets}}

[[Category:Rocket engines using hydrogen propellant]]
[[Category:North American Aviation]]
[[Category:Rocket engines using the expander cycle]]

RL10

2018-05-15T20:27:28Z

Blastr42: /* OmegA Upper Stage */

{{Use mdy dates|date=April 2017}}
{{Infobox rocket engine
|name =RL10
|image =RL-10 rocket engine (30432256313).jpg
|image_size =250
|caption =An RL10A-4 engine in London's [[Science Museum, London|Science Museum]]
|country_of_origin=[[United States|United States of America]]
|date =
|first_date =1962 (RL10A-1)
|last_date =
|designer = [[Pratt & Whitney]]/[[Marshall Space Flight Center|MSFC]]
|manufacturer = [[Pratt & Whitney Space Propulsion]] [[Pratt & Whitney Rocketdyne]] [[Aerojet Rocketdyne]]
|purpose =[[Upper stage]] engine
|associated =[[Atlas (rocket family)|Atlas]] [[Titan (rocket family)|Titan]] [[Delta IV]] [[Saturn I]]
|successor =
|status =In production
|type =liquid
|oxidiser =[[Liquid oxygen]]
|fuel =[[Liquid hydrogen]]
|mixture_ratio =5.5 or 5.88:1
|cycle =[[Expander cycle]]
|pumps =
|description =
|combustion_chamber=
|nozzle_ratio =84:1 or 280:1

|thrust =
|thrust_at_altitude=
|thrust(Vac) ={{convert|110|kN|abbr=on}}
|thrust(SL) =
|thrust_to_weight=
|chamber_pressure=
|specific_impulse=
|specific_impulse_vacuum={{convert|450|-|465.5|isp}}
|specific_impulse_sea_level=
|total_impulse =
|burn_time =700 seconds
|capacity =

|dimensions =
|length ={{convert|4.14|m|abbr=on}} w/ nozzle extended
|diameter ={{convert|2.13|m|abbr=on}}
|dry_weight ={{convert|277|kg|abbr=on}}

|used_in =[[Centaur (rocket stage)|Centaur]] [[S-IV]] [[Delta Cryogenic Second Stage|DCSS]]

|references =<ref name="EA10B2"/>
|notes =Performance values and dimensions are for RL10B-2.
}}
The '''RL10''' is a [[liquid-fuel rocket|liquid-fuel]] [[cryogenic rocket engine]] used on the [[Centaur (rocket stage)|Centaur]], [[S-IV]], and [[Delta Cryogenic Second Stage]] [[upper stage]]s. Built in the [[United States]] by [[Aerojet Rocketdyne]] (formerly by [[Pratt & Whitney Rocketdyne]]), the RL10 burns [[Cryogenic fuel|cryogenic]] [[liquid hydrogen]] and [[liquid oxygen]] propellants, with each engine producing {{convert|64.7|to(-)|110|kN|sigfig=5|abbr=on}} of [[thrust]] in vacuum depending on the version in use. The RL10 was the first liquid hydrogen rocket engine to be built in the United States, and development of the engine by [[Marshall Space Flight Center]] and [[Pratt & Whitney]] began in the 1950s, with the first flight occurring in 1961. Several versions of the engine have been flown, with two, the RL10A-4-2 and the RL10B-2, still being produced and flown on the [[Atlas V]] and [[Delta IV]].

The engine produces a [[specific impulse]] (''I''sp) of {{convert|373|to(-)|470|isp|abbr=on}} in a vacuum and has a mass ranging from {{convert|131|to(-)|317|kg|abbr=on}} (depending on version). Six RL10A-3 engines were used in the [[S-IV]] second stage of the [[Saturn I]] rocket, one or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets, and one RL10B-2 is used in the upper stage of [[Delta IV]] rockets.

==History==
The RL10 was first tested on the ground in 1959, at [[Pratt & Whitney]]'s Florida Research and Development Center in [[West Palm Beach, Florida]].<ref>Connors, p 319</ref> It was first flown in 1962 in an unsuccessful suborbital test;<ref name="gunter.centaur">{{cite web |title=Centaur |publisher=Gunter's Space Pages |url=http://space.skyrocket.de/doc_stage/centaur.htm}}</ref> the first successful flight took place on November 27, 1963.<ref>{{cite book |last=Sutton |first=George |title=History of liquid propellant rocket engines |publisher=American Institute of Aeronautics and Astronautics |date=2005 |isbn=1-56347-649-5}}</ref><ref>{{cite web |url=http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |title=Renowned Rocket Engine Celebrates 40 Years of Flight |date=November 24, 2003 |publisher=Pratt & Whitney |deadurl=yes |archiveurl=https://web.archive.org/web/20110614033822/http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |archivedate=June 14, 2011 |df=mdy-all}}</ref> For that launch, two RL10A-3 engines powered the [[Centaur (rocket stage)|Centaur]] upper stage of an [[Atlas (rocket family)|Atlas]] launch vehicle. The launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle.<ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1963-047A |title=Atlas Centaur 2 |publisher=NASA |work=[[National Space Science Data Center]]}}</ref> The RL10 was designed for the USAF from the beginning as a throttleable motor for the [[Lunex Project|Lunex]] lunar lander, finally putting this capability to use twenty years later in the [[McDonnell Douglas DC-X|DC-X]] VTOL vehicle.<ref>{{cite web |url=http://www.astronautix.com/articles/lunex.htm |title=Encyclopedia Astronautica—Lunex Project page |work=Encyclopedia Astronautica |first=Mark |last=Wade |deadurl=yes |archiveurl=https://web.archive.org/web/20060831191541/http://www.astronautix.com/articles/lunex.htm |archivedate=August 31, 2006 |df=mdy-all }}</ref>

===Improvements===
The RL10 has been upgraded over the years. One current model, the RL10B-2, powers the Delta IV second stage. It has been significantly modified from the original RL10 to improve performance. Some of the enhancements include an extendable nozzle and electro-mechanical [[gimbal]]ing for reduced weight and increased reliability. Current [[specific impulse]] is {{convert|464|isp}}.

A flaw in the [[brazing]] of an RL10B-2 combustion chamber was identified as the cause of failure for the May 4, 1999, [[Delta III]] launch carrying the Orion-3 [[communications satellite]].<ref>{{cite web |title=Delta 269 (Delta III) Investigation Report |url=http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |publisher=[[Boeing]] |date=August 16, 2000 |archiveurl=https://web.archive.org/web/20010616012841/http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |archivedate=June 16, 2001 |id=MDC 99H0047A}}</ref>

Aerojet Rocketdyne is working toward incorporating [[additive manufacturing]] into the RL10 construction process. The company conducted full-scale, hot-fire tests on an engine with a printed core main injector in March 2016,<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-successfully-tests-complex-3-d-printed-injector-worlds-most-reliable |title=Aerojet Rocketdyne Successfully Tests Complex 3-D Printed Injector in World's Most Reliable Upper Stage Rocket Engine |publisher=Aerojet Rocketdyne |date=March 7, 2016 |access-date=April 20, 2017}}</ref> and on an engine with a printed [[thrust chamber]] assembly in April 2017.<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-achieves-3-d-printing-milestone-successful-testing-full-scale-rl10-copper |title=Aerojet Rocketdyne Achieves 3-D Printing Milestone with Successful Testing of Full-Scale RL10 Copper Thrust Chamber Assembly |publisher=Aerojet Rocketdyne |date=April 3, 2017 |access-date=April 11, 2017}}</ref>

==Applications for the RL10==
Four modified RL10A-5 engines, all of them with the ability to be throttled, were used in the [[McDonnell Douglas DC-X]].<ref name=astro-dcx>{{cite web |url=http://www.astronautix.com/lvs/dcx.htm |title=DCX |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=January 4, 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20121228125150/http://www.astronautix.com/lvs/dcx.htm |archivedate=December 28, 2012 |df=}}</ref>

The [[DIRECT]] version 3.0 proposal to replace [[Ares I]] and [[Ares V]] with a family of rockets sharing a common core stage, recommends the RL10 for the second stage of their proposed J-246 and J-247 launch vehicles.<ref name = "direct_v3_specs">{{cite web |title=Jupiter Launch Vehicle – Technical Performance Summaries |url=http://www.launchcomplexmodels.com/Direct/media.htm |archiveurl=http://www.launchcomplexmodels.com/Direct/documents/Baseball_Cards/ |archivedate=June 8, 2009 |accessdate=July 18, 2009}}</ref> Up to seven RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the [[Ares V]] [[Earth Departure Stage]].

===Common Extensible Cryogenic Engine===
[[Image:Common Extensible Cryogenic Engine.jpg|thumb|The CECE at partial throttle]]

The Common Extensible Cryogenic Engine (CECE) is a testbed to develop RL10 engines that throttle well. NASA has contracted with [[Pratt & Whitney Rocketdyne]] to develop the CECE demonstrator engine.<ref>{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Common Extensible Cryogenic Engine (CECE) |publisher=United Technologies Corporation |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref> In 2007 its operability (with some "chugging") was demonstrated at 11-to-1 throttle ratios.<ref>{{cite web |url=https://science.nasa.gov/headlines/y2007/16jul_cece.htm |title=Throttling Back to the Moon |date=July 16, 2007 |publisher=NASA |deadurl=yes |archiveurl=https://web.archive.org/web/20100402064331/http://science.nasa.gov/headlines/y2007/16jul_cece.htm |archivedate=April 2, 2010 |df=mdy-all }}</ref> In 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature and flow of propellants.<ref>{{cite web |url=http://www.nasa.gov/home/hqnews/2009/jan/HQ_09-005_Cryo_engine_test.html |title=NASA Tests Engine Technology for Landing Astronauts on the Moon |date=January 14, 2009 |publisher=NASA}}</ref>

===Advanced Common Evolved Stage===
{{asof|2009}}, an enhanced version of the RL10 rocket engine was proposed to power the upper-stage versions of the [[Advanced Cryogenic Evolved Stage]] (ACES), a long-duration, low-boiloff extension of existing [[United Launch Alliance|ULA]] [[Centaur (rocket stage)|Centaur]] and [[Delta Cryogenic Second Stage]] (DCSS) technology.<ref name=aiaa20096566>{{cite journal |url=https://info.aiaa.org/tac/SMG/STTC/White%20Papers/DualThrustAxisLander(DTAL)2009.pdf |title=Robust Lunar Exploration Using an Efficient Lunar Lander Derived from Existing Upper Stages |journal=AIAA |first1=Bernard F. |last1=Kutter |first2=Frank |last2=Zegler |first3=Jon |last3=Barr |first4=Tim |last4=Bulk |first5=Brian |last5=Pitchford |date=2009 |ref=AIAA 2009-6566}}</ref> Long-duration ACES technology is explicitly designed to support [[geosynchronous]], [[cislunar]], and [[interplanetary mission|interplanetary]] missions as well as provide in-space [[propellant depot]]s in [[low-Earth orbit|LEO]] or at {{L2}} that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or [[interplanetary mission|interplanetary]] missions. Additional missions could include the provision of the [[delta-v|high-energy]] technical capacity for the cleanup of [[space debris]].<ref name=aiaa20100902>{{cite web |last=Zegler |first=Frank |title=Evolving to a Depot-Based Space Transportation Architecture |url=http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |work=AIAA SPACE 2010 Conference & Exposition |publisher=AIAA |accessdate=January 25, 2011 |author2=Bernard Kutter |date=September 2, 2010 |quote=''ACES design conceptualization has been underway at ULA for many years. It leverages design features of both the Centaur and Delta Cryogenic Second Stage (DCSS) upper stages and intends to supplement and perhaps replace these stages in the future. ...'' |deadurl=yes |archiveurl=https://web.archive.org/web/20111020010301/http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |archivedate=October 20, 2011 |df=mdy-all}}</ref>

===SLS Exploration Upper Stage===
In April 2016 it was reported NASA has chosen to use a design based on four RL10 engines for the [[Exploration Upper Stage]] to be used beginning with the crewed [[Exploration Mission 2|EM-2]] mission of the [[Space Launch System]].<ref>{{cite web |last=Bergin |first=Chris |title=MSFC propose Aerojet Rocketdyne supply EUS engines |url=https://www.nasaspaceflight.com/2016/04/msfc-aerojet-rocketdyne-eus-engines/ |work=[[NASASpaceFlight.com]] |accessdate=April 8, 2016 |date=April 7, 2016}}</ref> In October 2016 NASA confirmed these reports when it announced that the [[Exploration Upper Stage]] would utilize a new variant of the engine identified as the RL10C-3.<ref>{{cite web |title=Proven Engine Packs Big, In-Space Punch for NASA’s SLS Rocket |url=https://www.nasa.gov/exploration/systems/sls/proven-engine-packs-big-in-space-punch-for-nasa-s-sls-rocket.html |publisher=NASA |accessdate=November 22, 2017 |date=October 21, 2016}}</ref>

===OmegA Upper Stage===
In April 2018, Orbital ATK announced it would use two RL10C-5-1 engines for their [[Omega_(rocket)|OmegA]] to power the upper stage.<ref>{{cite web |title=RL-10 Selected for OmegA Rocket |url=http://www.rocket.com/article/rl10-selected-omega%E2%84%A2-rocket |publisher=Aerojet Rocketdyne |accessdate=May 14, 2018 |date=April 16, 2018}}</ref> Blue Origin's BE-3U and Airbus Safran's Vinci had also bee considered before the Aerojet Rocketdyne's engine was selected.

===Vulcan Centaur Upper Stage===
On May 11, 2018 United Launch Alliance (ULA) announced that Aerojet Rocketdyne would be strategic partner with their RL10C-X upper stage engine for ULA’s next-generation Vulcan Centaur rocket following a competitive procurement process.<ref>{{cite web |title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine |url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage |publisher=ULA |accessdate=May 13, 2018 |date=May 11, 2018}}</ref>

==Variants==
{| class="sortable wikitable"
! Version
! Status
! First flight
! Dry mass
! Thrust
! [[Specific impulse|''I''sp (<math>v_\text{e}</math>), vac]]
! Length
! Diameter
! [[Thrust-to-weight ratio|T:W]]
! O:F
! [[Expansion ratio]]
! Chamber pressure
! Burn time
! Associated stage
! Notes
|-
| RL10A-1
| Retired
| 1962
| {{cvt|131|kg}}
| {{cvt|15000|lbf|kN|order=flip}}
| {{cvt|425|isp}}
| {{cvt|1.73|m}}
| {{cvt|1.53|m}}
| 52:1
|
| 40:1
|
| 430 s
| [[Centaur (rocket stage)|Centaur A]]
| Prototype <ref name="EA10A1">{{cite web |url=http://www.astronautix.com/engines/rl10a1.htm |title=RL-10A-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115155200/http://www.astronautix.com/engines/rl10a1.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref><ref name="S2S"/><ref name="GSPAC">{{cite web |url=http://space.skyrocket.de/doc_lau/atlas_centaur.htm |title=Atlas Centaur |publisher=Gunter's Space Page |accessdate=February 29, 2012}}</ref>
|-
| RL10A-3
| Retired
| 1963
| {{cvt|131|kg}}
| {{cvt|65.6|kN}}
| {{cvt|444|isp}}
| {{cvt|2.49|m}}
| {{cvt|1.53|m}}
| 51:1
| 5:1
| 57:1
| {{cvt|32.75|bar}}
| 470 s
| [[Centaur (rocket stage)|Centaur]] B/C/D/E [[S-IV]]
| <ref name="EA10A3">{{cite web |url=http://www.astronautix.com/engines/rl10a3.htm |title=RL-10A-3 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111206225154/http://www.astronautix.com/engines/rl10a3.htm |archivedate=December 6, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4
| Retired
| 1992
| {{cvt|168|kg}}
| {{cvt|92.5|kN}}
| {{cvt|449|isp}}
| {{cvt|2.29|m}}
| {{cvt|1.17|m}}
| 56:1
| 5.5:1
| 84:1
|
| 392 s
| [[Centaur (rocket stage)|Centaur IIA]]
| <ref name="EA10A4">{{cite web |url=http://www.astronautix.com/engines/rl10a4.htm |title=RL-10A-4 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115172045/http://www.astronautix.com/engines/rl10a4.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-1
| Retired
| 2000
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.53|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIA]]
| <ref name="EA10A41">{{cite web |url=http://www.astronautix.com/engines/rl10a41.htm |title=RL-10A-4-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111117134046/http://www.astronautix.com/engines/rl10a41.htm |archivedate=November 17, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-2 {{Clarify|date=May 2016}}
| In production
| 2002
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.17|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIB]] Centaur V1 Centaur V2
| <ref name="EA10A42">{{cite web |url=http://www.astronautix.com/engines/rl10a42.htm |title=RL-10A-4-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120130143126/http://www.astronautix.com/engines/rl10a42.htm |archivedate=January 30, 2012 |df=mdy-all}}</ref><ref name=":0" />
|-
| RL10A-5
| Retired
| 1993
| {{cvt|143|kg}}
| {{cvt|64.7|kN}}
| {{cvt|373|isp}}
| {{cvt|1.07|m}}
| {{cvt|1.02|m}}
| 46:1
| 6:1
| 4:1
|
| 127 s
| [[McDonnell Douglas DC-X|DC-X]]
| <ref name="EA10A5">{{cite web |url=http://www.astronautix.com/engines/rl10a5.htm |title=RL-10A-5 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115141830/http://www.astronautix.com/engines/rl10a5.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10B-2
| In production
| 1998
| {{cvt|277|kg}}
| {{cvt|110|kN}}
| {{cvt|462|isp}}
| {{cvt|4.14|m}}
| {{cvt|2.13|m}}
| 40:1
| 5.88:1
| 280:1
| {{cvt|44.12|bar}}
| 5m: 1,125 s 4m: 700 s
| [[Delta Cryogenic Second Stage]]
| <ref name="EA10B2">{{cite web |url=http://www.astronautix.com/engines/rl10b2.htm |title=RL-10B-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm |archivedate=February 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|title=Delta IV Launch Services User's Guide, June 2013|url=https://www.ulalaunch.com/docs/default-source/rockets/delta-iv-user's-guide.pdf|website=ULA Launch|accessdate=15 March 2018}}</ref>
|-
| RL10B-X
| Cancelled
|
| {{cvt|317|kg}}
| {{cvt|93.4|kN}}
| {{cvt|470|isp}}
|
| {{cvt|1.53|m}}
| 30:1
|
| 250:1
|
| 408 s
| [[Centaur (rocket stage)|Centaur B-X]]
| <ref name="EA10BX">{{cite web |url=http://www.astronautix.com/engines/rl10bx.htm |title=RL-10B-X |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115150728/http://www.astronautix.com/engines/rl10bx.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| CECE
| Demonstrator project
|
| {{cvt|160|kg}}
| {{cvt|15000|lbf|kN|order=flip}}, throttle to 5–10%
| >{{cvt|445|isp}}
| {{cvt|1.53|m}}
|
|
|
|
|
|
|
| <ref name="PWRCECE">{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Commons Extensible Cryogenic Engine |publisher=Pratt & Whitney Rocketdyne |accessdate=February 28, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|url=http://www.rocket.com/common-extensible-cryogenic-engine|title=Common Extensible Cryogenic Engine - Aerojet Rocketdyne|author=|date=|website=www.rocket.com|accessdate=April 8, 2018}}</ref>
|-
| RL10C-1 {{Clarify|date=May 2016}}
| In production
| 2014
| {{cvt|420|lb|order=flip}}
| {{cvt|22890|lbf|kN|order=flip}}
| {{cvt|449.7|isp}}
| {{cvt|2.22|m}}
| {{cvt|1.44|m}}
| 57:1
| 5.5:1
| 130:1
|
| 2000 s
| Centaur SEC
| <ref name="CPS">{{cite web |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015783.pdf |title=Cryogenic Propulsion Stage |publisher=NASA |accessdate=October 11, 2014}}</ref><ref>{{cite web|url=http://forum.nasaspaceflight.com/index.php?topic=34891.0|title=Atlas-V with RL10C powered Centaur|author=|date=|website=forum.nasaspaceflight.com|accessdate=April 8, 2018}}</ref><ref>{{cite web |title=Evolution of Pratt & Whitney's cryogenic rocket engine RL-10 |url=http://b14643.de/Spacerockets/Diverse/P&W_RL10_engine/index.htm |accessdate=February 20, 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20160303141931/http://b14643.de/Spacerockets/Diverse/P%26W_RL10_engine/index.htm |archivedate=March 3, 2016 |df=mdy-all }}</ref><ref name=":0">{{cite web |title=RL10 Engine |url=http://www.rocket.com/rl10-engine |publisher=Aerojet Rocketdyne}}</ref>
|}

==Specifications==

===Original RL10===
[[File:RL-10 rocket engine.jpg|thumb|300px]]
* Thrust (altitude): 15,000 [[Pound-force|lbf]] (66.7 kN)<ref name="S2S">{{cite book |url=https://history.nasa.gov/SP-4206/ch5.htm |title=Stages to Saturn; A Technological History of the Apollo/Saturn Launch Vehicles |chapter=Unconventional Cryogenics: RL-10 and J-2 |publisher=NASA History Office |location=Washington, D.C. |first=Roger E. |last=Bilstein |date=1996 |accessdate=December 2, 2011}}</ref>
* Burn Time: 470 s
* Design: [[Expander cycle]]
* [[Specific impulse]]: {{convert|433|isp}}
* Engine weight—[[dry weight|dry]]: 298 lb (135 kg)
* Height: 68 in (1.73 m)
* Diameter: 39 in (0.99 m)
* Nozzle expansion ratio: 40 to 1
* Propellants: Liquid Oxygen & Liquid Hydrogen
* Propellant flow: 35 lb/s (16 kg/s)
* Contractor: Pratt & Whitney
* Vehicle application: [[Saturn I]] / [[S-IV]] 2nd stage—6-engines
* Vehicle application: [[Centaur (rocket stage)|Centaur]] upper stage—2-engines

===Current design===
[[File:Second stage of a Delta IV Medium rocket.jpg|thumb|Second stage of a Delta IV Medium rocket featuring an RL10B-2 engine]]

; RL10B-2 Specifications
*Thrust (altitude): 24,750 lbf (110.1 kN)<ref name=pwr_rl10b-2.pdf>{{cite web |url=http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |title=RL10B-2 |publisher=[[Pratt & Whitney Rocketdyne]] |date=2009 |accessdate=January 29, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120326211303/http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |archivedate=March 26, 2012 |df=mdy-all }}</ref>
*Design: [[Expander cycle]]<ref name="Sutton1998">{{cite journal |url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA397948 |title=50K expander cycle engine demonstration |journal=AIP Conference Proceedings |first1=A. M. |last1=Sutton |first2=S. D. |last2=Peery |first3=A. B. |last3=Minick |volume=420 |pages=1062–1065 |date=January 1998 |doi=10.1063/1.54719}}</ref>
*[[Specific impulse]]: {{convert|464|isp}}<ref name=pwr_rl10b-2.pdf />
*Engine weight - dry: 610 lb (277 kg)<ref name=pwr_rl10b-2.pdf />
*Height: 163 in (4.14 m)<ref name=pwr_rl10b-2.pdf />
*Diameter: 87 in (2.21 m)<ref name=pwr_rl10b-2.pdf />
*Expansion ratio: 280 to 1
*Mixture ratio: 5.88 to 1 <ref name=pwr_rl10b-2.pdf />
*Propellants: [[Liquid oxygen]] & [[liquid hydrogen]]<ref name=pwr_rl10b-2.pdf />
*Propellant flow: Oxidizer 41.42 lb/s (20.6 kg/s), fuel 7.72 lb/s (3.5 kg/s)<ref name=pwr_rl10b-2.pdf />
*Contractor: Pratt & Whitney
*Vehicle application: [[Delta III]], Delta IV second stage (1 engine)

; RL10A-4-2
The other current model, the RL10A-4-2, is the engine used on [[Centaur (rocket stage)|Centaur]] upper stage for [[Atlas V]].<ref name=pwr_rl10b-2.pdf />

==Possible successor==
In 2012 NASA joined with the US Air Force (USAF) to study next-generation upper stage propulsion, formalizing the agencies joint interests in a new upper stage engine to replace the Aerojet Rocketdyne RL10.
{{quote|"We know the list price on an RL10. If you look at cost over time, a very large portion of the unit cost of the EELVs is attributable to the propulsion systems, and the RL10 is a very old engine, and there's a lot of craftwork associated with its manufacture. ... That's what this study will figure out, is it worthwhile to build an RL10 replacement?"|author=Dale Thomas, Associated Director Technical, Marshall Space Flight Center<ref name=FG2012/>}}

From the study, NASA hopes to find a less expensive RL10-class engine for a third stage of the [[Space Launch System]] (SLS).<ref name=FG2012/><ref name=NASA-2012-04/>

USAF hopes to replace the Rocketdyne RL10 engines used on the upper stage of both the Lockheed Martin Atlas V and the Boeing Delta IV, known as [[Evolved Expendable Launch Vehicle]]s (EELV), that are the primary methods of putting US government satellites into space.<ref name=FG2012>{{cite web |last=Roseberg |first=Zach |title=NASA, US Air Force to study joint rocket engine |url=http://www.flightglobal.com/news/articles/nasa-us-air-force-to-study-joint-rocket-engine-370660/ |publisher=Flight Global |accessdate=June 1, 2012 |date=April 12, 2012}}</ref> This relates to the requirements study of the [[Affordable Upper Stage Engine Program]] (AUSEP) liquid rocket engine for use on upper stages of medium- and heavy-class launch vehicles, including the Evolved Expendable Launch Vehicle (EELV) family of launch vehicles.<ref name=NASA-2012-04>{{cite web |url=https://www.nasa.gov/centers/marshall/news/news/releases/2012/12-040.html |title=NASA Partners With U.S. Air Force to Study Common Rocket Propulsion Challenges |publisher=NASA |first=Kimberly |last=Newton |date=April 12, 2012}}</ref>

==Engines on display==
* An RL10 is on display at the [[New England Air Museum]], [[Windsor Locks, Connecticut]]<ref>{{cite web |url=http://neam.org/index.php?option=com_content&view=article&id=1112 |title=Pratt & Whitney RL10A-1 Rocket Engine |work=New England Air Museum |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], [[Chicago]], [[Illinois]]<ref name="histspace">{{cite web |url=http://historicspacecraft.com/rocket_engines.html |title=Photos of Rocket Engines |work=Historic Spacecraft |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[U.S. Space & Rocket Center]], [[Huntsville, Alabama]]<ref name="histspace"/>
* An RL10 is on display at [[Southern University]], [[Baton Rouge, Louisiana]]<ref>{{cite press release |url=http://www.prnewswire.com/news-releases/pratt--whitney-rocketdyne-donates-model-of-legendary-rl10-rocket-engine-to-southern-university-55982567.html |title=Pratt & Whitney Rocketdyne Donates Model of Legendary Rl10 Rocket Engine to Southern University |agency=PR Newswire |publisher=Pratt & Whitney Rocketdyne |first1=Nancy |last1=Colaguori |first2=Bryan |last2=Kidder |date=November 3, 2006 |accessdate=April 26, 2014}}</ref>
* Two RL10 engines are on display at [[US Space Walk of Fame]], [[Titusville, Florida]]<ref>{{cite web|url=https://www.facebook.com/SpaceWalkOfFame/photos/pcb.10152534325180820/10152534320660820/?type=1&theater|title=American Space Museum & Space Walk of Fame|author=|date=|website=www.facebook.com|accessdate=April 8, 2018}}</ref>
* An RL10 is on display in the Aerospace Engineering Department, Davis Hall at [[Auburn University]].{{cn|date=April 2017}}
* An RL10A-4 is on display at the Science Museum in London, UK.

==See also==
*[[Spacecraft propulsion]]
*[[RL60]]
*[[RD-0146]]
*[[XCOR Aerospace#ULA liquid hydrogen large engine development project|XCOR/ULA aluminum alloy nozzle engine]], under development in 2011

==References==
{{Reflist|30em}}

==Bibliography==
* {{cite book |last=Connors |first=Jack |title=The Engines of Pratt & Whitney: A Technical History |publisher=[[American Institute of Aeronautics and Astronautics]] |location=Reston. Virginia |date=2010 |isbn=978-1-60086-711-8 |url=}}

==External links==
{{Commons category|RL10 (rocket engine)|RL10}}
*[https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm RL10B-2 at Astronautix]
*[http://www.spaceflightnow.com/news/n0708/16rl10valve/ Spaceflight Now article]
*[http://www.spaceflightnow.com/news/n0901/26altair/ Spaceflight Now article]

{{Rocket engines}}
{{Atlas rockets}}
{{Thor and Delta rockets}}

[[Category:Rocket engines using hydrogen propellant]]
[[Category:North American Aviation]]
[[Category:Rocket engines using the expander cycle]]

RL10

2018-05-14T17:39:48Z

Blastr42: /* Applications for the RL10 */

{{Use mdy dates|date=April 2017}}
{{Infobox rocket engine
|name =RL10
|image =RL-10 rocket engine (30432256313).jpg
|image_size =250
|caption =An RL10A-4 engine in London's [[Science Museum, London|Science Museum]]
|country_of_origin=[[United States|United States of America]]
|date =
|first_date =1962 (RL10A-1)
|last_date =
|designer = [[Pratt & Whitney]]/[[Marshall Space Flight Center|MSFC]]
|manufacturer = [[Pratt & Whitney Space Propulsion]] [[Pratt & Whitney Rocketdyne]] [[Aerojet Rocketdyne]]
|purpose =[[Upper stage]] engine
|associated =[[Atlas (rocket family)|Atlas]] [[Titan (rocket family)|Titan]] [[Delta IV]] [[Saturn I]]
|successor =
|status =In production
|type =liquid
|oxidiser =[[Liquid oxygen]]
|fuel =[[Liquid hydrogen]]
|mixture_ratio =5.5 or 5.88:1
|cycle =[[Expander cycle]]
|pumps =
|description =
|combustion_chamber=
|nozzle_ratio =84:1 or 280:1

|thrust =
|thrust_at_altitude=
|thrust(Vac) ={{convert|110|kN|abbr=on}}
|thrust(SL) =
|thrust_to_weight=
|chamber_pressure=
|specific_impulse=
|specific_impulse_vacuum={{convert|450|-|465.5|isp}}
|specific_impulse_sea_level=
|total_impulse =
|burn_time =700 seconds
|capacity =

|dimensions =
|length ={{convert|4.14|m|abbr=on}} w/ nozzle extended
|diameter ={{convert|2.13|m|abbr=on}}
|dry_weight ={{convert|277|kg|abbr=on}}

|used_in =[[Centaur (rocket stage)|Centaur]] [[S-IV]] [[Delta Cryogenic Second Stage|DCSS]]

|references =<ref name="EA10B2"/>
|notes =Performance values and dimensions are for RL10B-2.
}}
The '''RL10''' is a [[liquid-fuel rocket|liquid-fuel]] [[cryogenic rocket engine]] used on the [[Centaur (rocket stage)|Centaur]], [[S-IV]], and [[Delta Cryogenic Second Stage]] [[upper stage]]s. Built in the [[United States]] by [[Aerojet Rocketdyne]] (formerly by [[Pratt & Whitney Rocketdyne]]), the RL10 burns [[Cryogenic fuel|cryogenic]] [[liquid hydrogen]] and [[liquid oxygen]] propellants, with each engine producing {{convert|64.7|to(-)|110|kN|sigfig=5|abbr=on}} of [[thrust]] in vacuum depending on the version in use. The RL10 was the first liquid hydrogen rocket engine to be built in the United States, and development of the engine by [[Marshall Space Flight Center]] and [[Pratt & Whitney]] began in the 1950s, with the first flight occurring in 1961. Several versions of the engine have been flown, with two, the RL10A-4-2 and the RL10B-2, still being produced and flown on the [[Atlas V]] and [[Delta IV]].

The engine produces a [[specific impulse]] (''I''sp) of {{convert|373|to(-)|470|isp|abbr=on}} in a vacuum and has a mass ranging from {{convert|131|to(-)|317|kg|abbr=on}} (depending on version). Six RL10A-3 engines were used in the [[S-IV]] second stage of the [[Saturn I]] rocket, one or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets, and one RL10B-2 is used in the upper stage of [[Delta IV]] rockets.

==History==
The RL10 was first tested on the ground in 1959, at [[Pratt & Whitney]]'s Florida Research and Development Center in [[West Palm Beach, Florida]].<ref>Connors, p 319</ref> It was first flown in 1962 in an unsuccessful suborbital test;<ref name="gunter.centaur">{{cite web |title=Centaur |publisher=Gunter's Space Pages |url=http://space.skyrocket.de/doc_stage/centaur.htm}}</ref> the first successful flight took place on November 27, 1963.<ref>{{cite book |last=Sutton |first=George |title=History of liquid propellant rocket engines |publisher=American Institute of Aeronautics and Astronautics |date=2005 |isbn=1-56347-649-5}}</ref><ref>{{cite web |url=http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |title=Renowned Rocket Engine Celebrates 40 Years of Flight |date=November 24, 2003 |publisher=Pratt & Whitney |deadurl=yes |archiveurl=https://web.archive.org/web/20110614033822/http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |archivedate=June 14, 2011 |df=mdy-all}}</ref> For that launch, two RL10A-3 engines powered the [[Centaur (rocket stage)|Centaur]] upper stage of an [[Atlas (rocket family)|Atlas]] launch vehicle. The launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle.<ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1963-047A |title=Atlas Centaur 2 |publisher=NASA |work=[[National Space Science Data Center]]}}</ref> The RL10 was designed for the USAF from the beginning as a throttleable motor for the [[Lunex Project|Lunex]] lunar lander, finally putting this capability to use twenty years later in the [[McDonnell Douglas DC-X|DC-X]] VTOL vehicle.<ref>{{cite web |url=http://www.astronautix.com/articles/lunex.htm |title=Encyclopedia Astronautica—Lunex Project page |work=Encyclopedia Astronautica |first=Mark |last=Wade |deadurl=yes |archiveurl=https://web.archive.org/web/20060831191541/http://www.astronautix.com/articles/lunex.htm |archivedate=August 31, 2006 |df=mdy-all }}</ref>

===Improvements===
The RL10 has been upgraded over the years. One current model, the RL10B-2, powers the Delta IV second stage. It has been significantly modified from the original RL10 to improve performance. Some of the enhancements include an extendable nozzle and electro-mechanical [[gimbal]]ing for reduced weight and increased reliability. Current [[specific impulse]] is {{convert|464|isp}}.

A flaw in the [[brazing]] of an RL10B-2 combustion chamber was identified as the cause of failure for the May 4, 1999, [[Delta III]] launch carrying the Orion-3 [[communications satellite]].<ref>{{cite web |title=Delta 269 (Delta III) Investigation Report |url=http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |publisher=[[Boeing]] |date=August 16, 2000 |archiveurl=https://web.archive.org/web/20010616012841/http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |archivedate=June 16, 2001 |id=MDC 99H0047A}}</ref>

Aerojet Rocketdyne is working toward incorporating [[additive manufacturing]] into the RL10 construction process. The company conducted full-scale, hot-fire tests on an engine with a printed core main injector in March 2016,<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-successfully-tests-complex-3-d-printed-injector-worlds-most-reliable |title=Aerojet Rocketdyne Successfully Tests Complex 3-D Printed Injector in World's Most Reliable Upper Stage Rocket Engine |publisher=Aerojet Rocketdyne |date=March 7, 2016 |access-date=April 20, 2017}}</ref> and on an engine with a printed [[thrust chamber]] assembly in April 2017.<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-achieves-3-d-printing-milestone-successful-testing-full-scale-rl10-copper |title=Aerojet Rocketdyne Achieves 3-D Printing Milestone with Successful Testing of Full-Scale RL10 Copper Thrust Chamber Assembly |publisher=Aerojet Rocketdyne |date=April 3, 2017 |access-date=April 11, 2017}}</ref>

==Applications for the RL10==
Four modified RL10A-5 engines, all of them with the ability to be throttled, were used in the [[McDonnell Douglas DC-X]].<ref name=astro-dcx>{{cite web |url=http://www.astronautix.com/lvs/dcx.htm |title=DCX |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=January 4, 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20121228125150/http://www.astronautix.com/lvs/dcx.htm |archivedate=December 28, 2012 |df=}}</ref>

The [[DIRECT]] version 3.0 proposal to replace [[Ares I]] and [[Ares V]] with a family of rockets sharing a common core stage, recommends the RL10 for the second stage of their proposed J-246 and J-247 launch vehicles.<ref name = "direct_v3_specs">{{cite web |title=Jupiter Launch Vehicle – Technical Performance Summaries |url=http://www.launchcomplexmodels.com/Direct/media.htm |archiveurl=http://www.launchcomplexmodels.com/Direct/documents/Baseball_Cards/ |archivedate=June 8, 2009 |accessdate=July 18, 2009}}</ref> Up to seven RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the [[Ares V]] [[Earth Departure Stage]].

===Common Extensible Cryogenic Engine===
[[Image:Common Extensible Cryogenic Engine.jpg|thumb|The CECE at partial throttle]]

The Common Extensible Cryogenic Engine (CECE) is a testbed to develop RL10 engines that throttle well. NASA has contracted with [[Pratt & Whitney Rocketdyne]] to develop the CECE demonstrator engine.<ref>{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Common Extensible Cryogenic Engine (CECE) |publisher=United Technologies Corporation |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref> In 2007 its operability (with some "chugging") was demonstrated at 11-to-1 throttle ratios.<ref>{{cite web |url=https://science.nasa.gov/headlines/y2007/16jul_cece.htm |title=Throttling Back to the Moon |date=July 16, 2007 |publisher=NASA |deadurl=yes |archiveurl=https://web.archive.org/web/20100402064331/http://science.nasa.gov/headlines/y2007/16jul_cece.htm |archivedate=April 2, 2010 |df=mdy-all }}</ref> In 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature and flow of propellants.<ref>{{cite web |url=http://www.nasa.gov/home/hqnews/2009/jan/HQ_09-005_Cryo_engine_test.html |title=NASA Tests Engine Technology for Landing Astronauts on the Moon |date=January 14, 2009 |publisher=NASA}}</ref>

===Advanced Common Evolved Stage===
{{asof|2009}}, an enhanced version of the RL10 rocket engine was proposed to power the upper-stage versions of the [[Advanced Cryogenic Evolved Stage]] (ACES), a long-duration, low-boiloff extension of existing [[United Launch Alliance|ULA]] [[Centaur (rocket stage)|Centaur]] and [[Delta Cryogenic Second Stage]] (DCSS) technology.<ref name=aiaa20096566>{{cite journal |url=https://info.aiaa.org/tac/SMG/STTC/White%20Papers/DualThrustAxisLander(DTAL)2009.pdf |title=Robust Lunar Exploration Using an Efficient Lunar Lander Derived from Existing Upper Stages |journal=AIAA |first1=Bernard F. |last1=Kutter |first2=Frank |last2=Zegler |first3=Jon |last3=Barr |first4=Tim |last4=Bulk |first5=Brian |last5=Pitchford |date=2009 |ref=AIAA 2009-6566}}</ref> Long-duration ACES technology is explicitly designed to support [[geosynchronous]], [[cislunar]], and [[interplanetary mission|interplanetary]] missions as well as provide in-space [[propellant depot]]s in [[low-Earth orbit|LEO]] or at {{L2}} that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or [[interplanetary mission|interplanetary]] missions. Additional missions could include the provision of the [[delta-v|high-energy]] technical capacity for the cleanup of [[space debris]].<ref name=aiaa20100902>{{cite web |last=Zegler |first=Frank |title=Evolving to a Depot-Based Space Transportation Architecture |url=http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |work=AIAA SPACE 2010 Conference & Exposition |publisher=AIAA |accessdate=January 25, 2011 |author2=Bernard Kutter |date=September 2, 2010 |quote=''ACES design conceptualization has been underway at ULA for many years. It leverages design features of both the Centaur and Delta Cryogenic Second Stage (DCSS) upper stages and intends to supplement and perhaps replace these stages in the future. ...'' |deadurl=yes |archiveurl=https://web.archive.org/web/20111020010301/http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |archivedate=October 20, 2011 |df=mdy-all}}</ref>

===SLS Exploration Upper Stage===
In April 2016 it was reported NASA has chosen to use a design based on four RL10 engines for the [[Exploration Upper Stage]] to be used beginning with the crewed [[Exploration Mission 2|EM-2]] mission of the [[Space Launch System]].<ref>{{cite web |last=Bergin |first=Chris |title=MSFC propose Aerojet Rocketdyne supply EUS engines |url=https://www.nasaspaceflight.com/2016/04/msfc-aerojet-rocketdyne-eus-engines/ |work=[[NASASpaceFlight.com]] |accessdate=April 8, 2016 |date=April 7, 2016}}</ref> In October 2016 NASA confirmed these reports when it announced that the [[Exploration Upper Stage]] would utilize a new variant of the engine identified as the RL10C-3.<ref>{{cite web |title=Proven Engine Packs Big, In-Space Punch for NASA’s SLS Rocket |url=https://www.nasa.gov/exploration/systems/sls/proven-engine-packs-big-in-space-punch-for-nasa-s-sls-rocket.html |publisher=NASA |accessdate=November 22, 2017 |date=October 21, 2016}}</ref>

===OmegA Upper Stage===
In April 2018, Orbital ATK announced it would use two RL10C-5-1 engines for their [[OmegA|Omega_(rocket)]] to power the upper stage.<ref>{{cite web |title=RL-10 Selected for OmegA Rocket |url=http://www.rocket.com/article/rl10-selected-omega%E2%84%A2-rocket |publisher=Aerojet Rocketdyne |accessdate=May 14, 2018 |date=April 16, 2018}}</ref> Blue Origin's BE-3U and Airbus Safran's Vinci had also bee considered before the Aerojet Rocketdyne's engine was selected.

===Vulcan Centaur Upper Stage===
On May 11, 2018 United Launch Alliance (ULA) announced that Aerojet Rocketdyne would be strategic partner with their RL10C-X upper stage engine for ULA’s next-generation Vulcan Centaur rocket following a competitive procurement process.<ref>{{cite web |title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine |url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage |publisher=ULA |accessdate=May 13, 2018 |date=May 11, 2018}}</ref>

==Variants==
{| class="sortable wikitable"
! Version
! Status
! First flight
! Dry mass
! Thrust
! [[Specific impulse|''I''sp (<math>v_\text{e}</math>), vac]]
! Length
! Diameter
! [[Thrust-to-weight ratio|T:W]]
! O:F
! [[Expansion ratio]]
! Chamber pressure
! Burn time
! Associated stage
! Notes
|-
| RL10A-1
| Retired
| 1962
| {{cvt|131|kg}}
| {{cvt|15000|lbf|kN|order=flip}}
| {{cvt|425|isp}}
| {{cvt|1.73|m}}
| {{cvt|1.53|m}}
| 52:1
|
| 40:1
|
| 430 s
| [[Centaur (rocket stage)|Centaur A]]
| Prototype <ref name="EA10A1">{{cite web |url=http://www.astronautix.com/engines/rl10a1.htm |title=RL-10A-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115155200/http://www.astronautix.com/engines/rl10a1.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref><ref name="S2S"/><ref name="GSPAC">{{cite web |url=http://space.skyrocket.de/doc_lau/atlas_centaur.htm |title=Atlas Centaur |publisher=Gunter's Space Page |accessdate=February 29, 2012}}</ref>
|-
| RL10A-3
| Retired
| 1963
| {{cvt|131|kg}}
| {{cvt|65.6|kN}}
| {{cvt|444|isp}}
| {{cvt|2.49|m}}
| {{cvt|1.53|m}}
| 51:1
| 5:1
| 57:1
| {{cvt|32.75|bar}}
| 470 s
| [[Centaur (rocket stage)|Centaur]] B/C/D/E [[S-IV]]
| <ref name="EA10A3">{{cite web |url=http://www.astronautix.com/engines/rl10a3.htm |title=RL-10A-3 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111206225154/http://www.astronautix.com/engines/rl10a3.htm |archivedate=December 6, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4
| Retired
| 1992
| {{cvt|168|kg}}
| {{cvt|92.5|kN}}
| {{cvt|449|isp}}
| {{cvt|2.29|m}}
| {{cvt|1.17|m}}
| 56:1
| 5.5:1
| 84:1
|
| 392 s
| [[Centaur (rocket stage)|Centaur IIA]]
| <ref name="EA10A4">{{cite web |url=http://www.astronautix.com/engines/rl10a4.htm |title=RL-10A-4 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115172045/http://www.astronautix.com/engines/rl10a4.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-1
| Retired
| 2000
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.53|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIA]]
| <ref name="EA10A41">{{cite web |url=http://www.astronautix.com/engines/rl10a41.htm |title=RL-10A-4-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111117134046/http://www.astronautix.com/engines/rl10a41.htm |archivedate=November 17, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-2 {{Clarify|date=May 2016}}
| In production
| 2002
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.17|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIB]] Centaur V1 Centaur V2
| <ref name="EA10A42">{{cite web |url=http://www.astronautix.com/engines/rl10a42.htm |title=RL-10A-4-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120130143126/http://www.astronautix.com/engines/rl10a42.htm |archivedate=January 30, 2012 |df=mdy-all}}</ref><ref name=":0" />
|-
| RL10A-5
| Retired
| 1993
| {{cvt|143|kg}}
| {{cvt|64.7|kN}}
| {{cvt|373|isp}}
| {{cvt|1.07|m}}
| {{cvt|1.02|m}}
| 46:1
| 6:1
| 4:1
|
| 127 s
| [[McDonnell Douglas DC-X|DC-X]]
| <ref name="EA10A5">{{cite web |url=http://www.astronautix.com/engines/rl10a5.htm |title=RL-10A-5 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115141830/http://www.astronautix.com/engines/rl10a5.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10B-2
| In production
| 1998
| {{cvt|277|kg}}
| {{cvt|110|kN}}
| {{cvt|462|isp}}
| {{cvt|4.14|m}}
| {{cvt|2.13|m}}
| 40:1
| 5.88:1
| 280:1
| {{cvt|44.12|bar}}
| 5m: 1,125 s 4m: 700 s
| [[Delta Cryogenic Second Stage]]
| <ref name="EA10B2">{{cite web |url=http://www.astronautix.com/engines/rl10b2.htm |title=RL-10B-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm |archivedate=February 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|title=Delta IV Launch Services User's Guide, June 2013|url=https://www.ulalaunch.com/docs/default-source/rockets/delta-iv-user's-guide.pdf|website=ULA Launch|accessdate=15 March 2018}}</ref>
|-
| RL10B-X
| Cancelled
|
| {{cvt|317|kg}}
| {{cvt|93.4|kN}}
| {{cvt|470|isp}}
|
| {{cvt|1.53|m}}
| 30:1
|
| 250:1
|
| 408 s
| [[Centaur (rocket stage)|Centaur B-X]]
| <ref name="EA10BX">{{cite web |url=http://www.astronautix.com/engines/rl10bx.htm |title=RL-10B-X |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115150728/http://www.astronautix.com/engines/rl10bx.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| CECE
| Demonstrator project
|
| {{cvt|160|kg}}
| {{cvt|15000|lbf|kN|order=flip}}, throttle to 5–10%
| >{{cvt|445|isp}}
| {{cvt|1.53|m}}
|
|
|
|
|
|
|
| <ref name="PWRCECE">{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Commons Extensible Cryogenic Engine |publisher=Pratt & Whitney Rocketdyne |accessdate=February 28, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|url=http://www.rocket.com/common-extensible-cryogenic-engine|title=Common Extensible Cryogenic Engine - Aerojet Rocketdyne|author=|date=|website=www.rocket.com|accessdate=April 8, 2018}}</ref>
|-
| RL10C-1 {{Clarify|date=May 2016}}
| In production
| 2014
| {{cvt|420|lb|order=flip}}
| {{cvt|22890|lbf|kN|order=flip}}
| {{cvt|449.7|isp}}
| {{cvt|2.22|m}}
| {{cvt|1.44|m}}
| 57:1
| 5.5:1
| 130:1
|
| 2000 s
| Centaur SEC
| <ref name="CPS">{{cite web |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015783.pdf |title=Cryogenic Propulsion Stage |publisher=NASA |accessdate=October 11, 2014}}</ref><ref>{{cite web|url=http://forum.nasaspaceflight.com/index.php?topic=34891.0|title=Atlas-V with RL10C powered Centaur|author=|date=|website=forum.nasaspaceflight.com|accessdate=April 8, 2018}}</ref><ref>{{cite web |title=Evolution of Pratt & Whitney's cryogenic rocket engine RL-10 |url=http://b14643.de/Spacerockets/Diverse/P&W_RL10_engine/index.htm |accessdate=February 20, 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20160303141931/http://b14643.de/Spacerockets/Diverse/P%26W_RL10_engine/index.htm |archivedate=March 3, 2016 |df=mdy-all }}</ref><ref name=":0">{{cite web |title=RL10 Engine |url=http://www.rocket.com/rl10-engine |publisher=Aerojet Rocketdyne}}</ref>
|}

==Specifications==

===Original RL10===
[[File:RL-10 rocket engine.jpg|thumb|300px]]
* Thrust (altitude): 15,000 [[Pound-force|lbf]] (66.7 kN)<ref name="S2S">{{cite book |url=https://history.nasa.gov/SP-4206/ch5.htm |title=Stages to Saturn; A Technological History of the Apollo/Saturn Launch Vehicles |chapter=Unconventional Cryogenics: RL-10 and J-2 |publisher=NASA History Office |location=Washington, D.C. |first=Roger E. |last=Bilstein |date=1996 |accessdate=December 2, 2011}}</ref>
* Burn Time: 470 s
* Design: [[Expander cycle]]
* [[Specific impulse]]: {{convert|433|isp}}
* Engine weight—[[dry weight|dry]]: 298 lb (135 kg)
* Height: 68 in (1.73 m)
* Diameter: 39 in (0.99 m)
* Nozzle expansion ratio: 40 to 1
* Propellants: Liquid Oxygen & Liquid Hydrogen
* Propellant flow: 35 lb/s (16 kg/s)
* Contractor: Pratt & Whitney
* Vehicle application: [[Saturn I]] / [[S-IV]] 2nd stage—6-engines
* Vehicle application: [[Centaur (rocket stage)|Centaur]] upper stage—2-engines

===Current design===
[[File:Second stage of a Delta IV Medium rocket.jpg|thumb|Second stage of a Delta IV Medium rocket featuring an RL10B-2 engine]]

; RL10B-2 Specifications
*Thrust (altitude): 24,750 lbf (110.1 kN)<ref name=pwr_rl10b-2.pdf>{{cite web |url=http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |title=RL10B-2 |publisher=[[Pratt & Whitney Rocketdyne]] |date=2009 |accessdate=January 29, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120326211303/http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |archivedate=March 26, 2012 |df=mdy-all }}</ref>
*Design: [[Expander cycle]]<ref name="Sutton1998">{{cite journal |url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA397948 |title=50K expander cycle engine demonstration |journal=AIP Conference Proceedings |first1=A. M. |last1=Sutton |first2=S. D. |last2=Peery |first3=A. B. |last3=Minick |volume=420 |pages=1062–1065 |date=January 1998 |doi=10.1063/1.54719}}</ref>
*[[Specific impulse]]: {{convert|464|isp}}<ref name=pwr_rl10b-2.pdf />
*Engine weight - dry: 610 lb (277 kg)<ref name=pwr_rl10b-2.pdf />
*Height: 163 in (4.14 m)<ref name=pwr_rl10b-2.pdf />
*Diameter: 87 in (2.21 m)<ref name=pwr_rl10b-2.pdf />
*Expansion ratio: 280 to 1
*Mixture ratio: 5.88 to 1 <ref name=pwr_rl10b-2.pdf />
*Propellants: [[Liquid oxygen]] & [[liquid hydrogen]]<ref name=pwr_rl10b-2.pdf />
*Propellant flow: Oxidizer 41.42 lb/s (20.6 kg/s), fuel 7.72 lb/s (3.5 kg/s)<ref name=pwr_rl10b-2.pdf />
*Contractor: Pratt & Whitney
*Vehicle application: [[Delta III]], Delta IV second stage (1 engine)

; RL10A-4-2
The other current model, the RL10A-4-2, is the engine used on [[Centaur (rocket stage)|Centaur]] upper stage for [[Atlas V]].<ref name=pwr_rl10b-2.pdf />

==Possible successor==
In 2012 NASA joined with the US Air Force (USAF) to study next-generation upper stage propulsion, formalizing the agencies joint interests in a new upper stage engine to replace the Aerojet Rocketdyne RL10.
{{quote|"We know the list price on an RL10. If you look at cost over time, a very large portion of the unit cost of the EELVs is attributable to the propulsion systems, and the RL10 is a very old engine, and there's a lot of craftwork associated with its manufacture. ... That's what this study will figure out, is it worthwhile to build an RL10 replacement?"|author=Dale Thomas, Associated Director Technical, Marshall Space Flight Center<ref name=FG2012/>}}

From the study, NASA hopes to find a less expensive RL10-class engine for a third stage of the [[Space Launch System]] (SLS).<ref name=FG2012/><ref name=NASA-2012-04/>

USAF hopes to replace the Rocketdyne RL10 engines used on the upper stage of both the Lockheed Martin Atlas V and the Boeing Delta IV, known as [[Evolved Expendable Launch Vehicle]]s (EELV), that are the primary methods of putting US government satellites into space.<ref name=FG2012>{{cite web |last=Roseberg |first=Zach |title=NASA, US Air Force to study joint rocket engine |url=http://www.flightglobal.com/news/articles/nasa-us-air-force-to-study-joint-rocket-engine-370660/ |publisher=Flight Global |accessdate=June 1, 2012 |date=April 12, 2012}}</ref> This relates to the requirements study of the [[Affordable Upper Stage Engine Program]] (AUSEP) liquid rocket engine for use on upper stages of medium- and heavy-class launch vehicles, including the Evolved Expendable Launch Vehicle (EELV) family of launch vehicles.<ref name=NASA-2012-04>{{cite web |url=https://www.nasa.gov/centers/marshall/news/news/releases/2012/12-040.html |title=NASA Partners With U.S. Air Force to Study Common Rocket Propulsion Challenges |publisher=NASA |first=Kimberly |last=Newton |date=April 12, 2012}}</ref>

==Engines on display==
* An RL10 is on display at the [[New England Air Museum]], [[Windsor Locks, Connecticut]]<ref>{{cite web |url=http://neam.org/index.php?option=com_content&view=article&id=1112 |title=Pratt & Whitney RL10A-1 Rocket Engine |work=New England Air Museum |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], [[Chicago]], [[Illinois]]<ref name="histspace">{{cite web |url=http://historicspacecraft.com/rocket_engines.html |title=Photos of Rocket Engines |work=Historic Spacecraft |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[U.S. Space & Rocket Center]], [[Huntsville, Alabama]]<ref name="histspace"/>
* An RL10 is on display at [[Southern University]], [[Baton Rouge, Louisiana]]<ref>{{cite press release |url=http://www.prnewswire.com/news-releases/pratt--whitney-rocketdyne-donates-model-of-legendary-rl10-rocket-engine-to-southern-university-55982567.html |title=Pratt & Whitney Rocketdyne Donates Model of Legendary Rl10 Rocket Engine to Southern University |agency=PR Newswire |publisher=Pratt & Whitney Rocketdyne |first1=Nancy |last1=Colaguori |first2=Bryan |last2=Kidder |date=November 3, 2006 |accessdate=April 26, 2014}}</ref>
* Two RL10 engines are on display at [[US Space Walk of Fame]], [[Titusville, Florida]]<ref>{{cite web|url=https://www.facebook.com/SpaceWalkOfFame/photos/pcb.10152534325180820/10152534320660820/?type=1&theater|title=American Space Museum & Space Walk of Fame|author=|date=|website=www.facebook.com|accessdate=April 8, 2018}}</ref>
* An RL10 is on display in the Aerospace Engineering Department, Davis Hall at [[Auburn University]].{{cn|date=April 2017}}
* An RL10A-4 is on display at the Science Museum in London, UK.

==See also==
*[[Spacecraft propulsion]]
*[[RL60]]
*[[RD-0146]]
*[[XCOR Aerospace#ULA liquid hydrogen large engine development project|XCOR/ULA aluminum alloy nozzle engine]], under development in 2011

==References==
{{Reflist|30em}}

==Bibliography==
* {{cite book |last=Connors |first=Jack |title=The Engines of Pratt & Whitney: A Technical History |publisher=[[American Institute of Aeronautics and Astronautics]] |location=Reston. Virginia |date=2010 |isbn=978-1-60086-711-8 |url=}}

==External links==
{{Commons category|RL10 (rocket engine)|RL10}}
*[https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm RL10B-2 at Astronautix]
*[http://www.spaceflightnow.com/news/n0708/16rl10valve/ Spaceflight Now article]
*[http://www.spaceflightnow.com/news/n0901/26altair/ Spaceflight Now article]

{{Rocket engines}}
{{Atlas rockets}}
{{Thor and Delta rockets}}

[[Category:Rocket engines using hydrogen propellant]]
[[Category:North American Aviation]]
[[Category:Rocket engines using the expander cycle]]

RL10

2018-05-14T17:17:35Z

Blastr42: /* Vulcan Centaur Upper Stage */

{{Use mdy dates|date=April 2017}}
{{Infobox rocket engine
|name =RL10
|image =RL-10 rocket engine (30432256313).jpg
|image_size =250
|caption =An RL10A-4 engine in London's [[Science Museum, London|Science Museum]]
|country_of_origin=[[United States|United States of America]]
|date =
|first_date =1962 (RL10A-1)
|last_date =
|designer = [[Pratt & Whitney]]/[[Marshall Space Flight Center|MSFC]]
|manufacturer = [[Pratt & Whitney Space Propulsion]] [[Pratt & Whitney Rocketdyne]] [[Aerojet Rocketdyne]]
|purpose =[[Upper stage]] engine
|associated =[[Atlas (rocket family)|Atlas]] [[Titan (rocket family)|Titan]] [[Delta IV]] [[Saturn I]]
|successor =
|status =In production
|type =liquid
|oxidiser =[[Liquid oxygen]]
|fuel =[[Liquid hydrogen]]
|mixture_ratio =5.5 or 5.88:1
|cycle =[[Expander cycle]]
|pumps =
|description =
|combustion_chamber=
|nozzle_ratio =84:1 or 280:1

|thrust =
|thrust_at_altitude=
|thrust(Vac) ={{convert|110|kN|abbr=on}}
|thrust(SL) =
|thrust_to_weight=
|chamber_pressure=
|specific_impulse=
|specific_impulse_vacuum={{convert|450|-|465.5|isp}}
|specific_impulse_sea_level=
|total_impulse =
|burn_time =700 seconds
|capacity =

|dimensions =
|length ={{convert|4.14|m|abbr=on}} w/ nozzle extended
|diameter ={{convert|2.13|m|abbr=on}}
|dry_weight ={{convert|277|kg|abbr=on}}

|used_in =[[Centaur (rocket stage)|Centaur]] [[S-IV]] [[Delta Cryogenic Second Stage|DCSS]]

|references =<ref name="EA10B2"/>
|notes =Performance values and dimensions are for RL10B-2.
}}
The '''RL10''' is a [[liquid-fuel rocket|liquid-fuel]] [[cryogenic rocket engine]] used on the [[Centaur (rocket stage)|Centaur]], [[S-IV]], and [[Delta Cryogenic Second Stage]] [[upper stage]]s. Built in the [[United States]] by [[Aerojet Rocketdyne]] (formerly by [[Pratt & Whitney Rocketdyne]]), the RL10 burns [[Cryogenic fuel|cryogenic]] [[liquid hydrogen]] and [[liquid oxygen]] propellants, with each engine producing {{convert|64.7|to(-)|110|kN|sigfig=5|abbr=on}} of [[thrust]] in vacuum depending on the version in use. The RL10 was the first liquid hydrogen rocket engine to be built in the United States, and development of the engine by [[Marshall Space Flight Center]] and [[Pratt & Whitney]] began in the 1950s, with the first flight occurring in 1961. Several versions of the engine have been flown, with two, the RL10A-4-2 and the RL10B-2, still being produced and flown on the [[Atlas V]] and [[Delta IV]].

The engine produces a [[specific impulse]] (''I''sp) of {{convert|373|to(-)|470|isp|abbr=on}} in a vacuum and has a mass ranging from {{convert|131|to(-)|317|kg|abbr=on}} (depending on version). Six RL10A-3 engines were used in the [[S-IV]] second stage of the [[Saturn I]] rocket, one or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets, and one RL10B-2 is used in the upper stage of [[Delta IV]] rockets.

==History==
The RL10 was first tested on the ground in 1959, at [[Pratt & Whitney]]'s Florida Research and Development Center in [[West Palm Beach, Florida]].<ref>Connors, p 319</ref> It was first flown in 1962 in an unsuccessful suborbital test;<ref name="gunter.centaur">{{cite web |title=Centaur |publisher=Gunter's Space Pages |url=http://space.skyrocket.de/doc_stage/centaur.htm}}</ref> the first successful flight took place on November 27, 1963.<ref>{{cite book |last=Sutton |first=George |title=History of liquid propellant rocket engines |publisher=American Institute of Aeronautics and Astronautics |date=2005 |isbn=1-56347-649-5}}</ref><ref>{{cite web |url=http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |title=Renowned Rocket Engine Celebrates 40 Years of Flight |date=November 24, 2003 |publisher=Pratt & Whitney |deadurl=yes |archiveurl=https://web.archive.org/web/20110614033822/http://www.pratt-whitney.com/vgn-ext-templating/v/index.jsp?vgnextoid=cabbe002c2f3c010VgnVCM1000000881000aRCRD&vgnextchannel=7dfc34890cb06110VgnVCM1000004601000aRCRD&vgnextfmt=default |archivedate=June 14, 2011 |df=mdy-all}}</ref> For that launch, two RL10A-3 engines powered the [[Centaur (rocket stage)|Centaur]] upper stage of an [[Atlas (rocket family)|Atlas]] launch vehicle. The launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle.<ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1963-047A |title=Atlas Centaur 2 |publisher=NASA |work=[[National Space Science Data Center]]}}</ref> The RL10 was designed for the USAF from the beginning as a throttleable motor for the [[Lunex Project|Lunex]] lunar lander, finally putting this capability to use twenty years later in the [[McDonnell Douglas DC-X|DC-X]] VTOL vehicle.<ref>{{cite web |url=http://www.astronautix.com/articles/lunex.htm |title=Encyclopedia Astronautica—Lunex Project page |work=Encyclopedia Astronautica |first=Mark |last=Wade |deadurl=yes |archiveurl=https://web.archive.org/web/20060831191541/http://www.astronautix.com/articles/lunex.htm |archivedate=August 31, 2006 |df=mdy-all }}</ref>

===Improvements===
The RL10 has been upgraded over the years. One current model, the RL10B-2, powers the Delta IV second stage. It has been significantly modified from the original RL10 to improve performance. Some of the enhancements include an extendable nozzle and electro-mechanical [[gimbal]]ing for reduced weight and increased reliability. Current [[specific impulse]] is {{convert|464|isp}}.

A flaw in the [[brazing]] of an RL10B-2 combustion chamber was identified as the cause of failure for the May 4, 1999, [[Delta III]] launch carrying the Orion-3 [[communications satellite]].<ref>{{cite web |title=Delta 269 (Delta III) Investigation Report |url=http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |publisher=[[Boeing]] |date=August 16, 2000 |archiveurl=https://web.archive.org/web/20010616012841/http://www.boeing.com/defense-space/space/delta/delta3/d3_report.pdf |archivedate=June 16, 2001 |id=MDC 99H0047A}}</ref>

Aerojet Rocketdyne is working toward incorporating [[additive manufacturing]] into the RL10 construction process. The company conducted full-scale, hot-fire tests on an engine with a printed core main injector in March 2016,<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-successfully-tests-complex-3-d-printed-injector-worlds-most-reliable |title=Aerojet Rocketdyne Successfully Tests Complex 3-D Printed Injector in World's Most Reliable Upper Stage Rocket Engine |publisher=Aerojet Rocketdyne |date=March 7, 2016 |access-date=April 20, 2017}}</ref> and on an engine with a printed [[thrust chamber]] assembly in April 2017.<ref>{{Cite press release |url=http://www.rocket.com/article/aerojet-rocketdyne-achieves-3-d-printing-milestone-successful-testing-full-scale-rl10-copper |title=Aerojet Rocketdyne Achieves 3-D Printing Milestone with Successful Testing of Full-Scale RL10 Copper Thrust Chamber Assembly |publisher=Aerojet Rocketdyne |date=April 3, 2017 |access-date=April 11, 2017}}</ref>

==Applications for the RL10==
Four modified RL10A-5 engines, all of them with the ability to be throttled, were used in the [[McDonnell Douglas DC-X]].<ref name=astro-dcx>{{cite web |url=http://www.astronautix.com/lvs/dcx.htm |title=DCX |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=January 4, 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20121228125150/http://www.astronautix.com/lvs/dcx.htm |archivedate=December 28, 2012 |df=}}</ref>

The [[DIRECT]] version 3.0 proposal to replace [[Ares I]] and [[Ares V]] with a family of rockets sharing a common core stage, recommends the RL10 for the second stage of their proposed J-246 and J-247 launch vehicles.<ref name = "direct_v3_specs">{{cite web |title=Jupiter Launch Vehicle – Technical Performance Summaries |url=http://www.launchcomplexmodels.com/Direct/media.htm |archiveurl=http://www.launchcomplexmodels.com/Direct/documents/Baseball_Cards/ |archivedate=June 8, 2009 |accessdate=July 18, 2009}}</ref> Up to seven RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the [[Ares V]] [[Earth Departure Stage]].

===Common Extensible Cryogenic Engine===
[[Image:Common Extensible Cryogenic Engine.jpg|thumb|The CECE at partial throttle]]

The Common Extensible Cryogenic Engine (CECE) is a testbed to develop RL10 engines that throttle well. NASA has contracted with [[Pratt & Whitney Rocketdyne]] to develop the CECE demonstrator engine.<ref>{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Common Extensible Cryogenic Engine (CECE) |publisher=United Technologies Corporation |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref> In 2007 its operability (with some "chugging") was demonstrated at 11-to-1 throttle ratios.<ref>{{cite web |url=https://science.nasa.gov/headlines/y2007/16jul_cece.htm |title=Throttling Back to the Moon |date=July 16, 2007 |publisher=NASA |deadurl=yes |archiveurl=https://web.archive.org/web/20100402064331/http://science.nasa.gov/headlines/y2007/16jul_cece.htm |archivedate=April 2, 2010 |df=mdy-all }}</ref> In 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature and flow of propellants.<ref>{{cite web |url=http://www.nasa.gov/home/hqnews/2009/jan/HQ_09-005_Cryo_engine_test.html |title=NASA Tests Engine Technology for Landing Astronauts on the Moon |date=January 14, 2009 |publisher=NASA}}</ref>

===Advanced Common Evolved Stage===
{{asof|2009}}, an enhanced version of the RL10 rocket engine was proposed to power the upper-stage versions of the [[Advanced Cryogenic Evolved Stage]] (ACES), a long-duration, low-boiloff extension of existing [[United Launch Alliance|ULA]] [[Centaur (rocket stage)|Centaur]] and [[Delta Cryogenic Second Stage]] (DCSS) technology.<ref name=aiaa20096566>{{cite journal |url=https://info.aiaa.org/tac/SMG/STTC/White%20Papers/DualThrustAxisLander(DTAL)2009.pdf |title=Robust Lunar Exploration Using an Efficient Lunar Lander Derived from Existing Upper Stages |journal=AIAA |first1=Bernard F. |last1=Kutter |first2=Frank |last2=Zegler |first3=Jon |last3=Barr |first4=Tim |last4=Bulk |first5=Brian |last5=Pitchford |date=2009 |ref=AIAA 2009-6566}}</ref> Long-duration ACES technology is explicitly designed to support [[geosynchronous]], [[cislunar]], and [[interplanetary mission|interplanetary]] missions as well as provide in-space [[propellant depot]]s in [[low-Earth orbit|LEO]] or at {{L2}} that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or [[interplanetary mission|interplanetary]] missions. Additional missions could include the provision of the [[delta-v|high-energy]] technical capacity for the cleanup of [[space debris]].<ref name=aiaa20100902>{{cite web |last=Zegler |first=Frank |title=Evolving to a Depot-Based Space Transportation Architecture |url=http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |work=AIAA SPACE 2010 Conference & Exposition |publisher=AIAA |accessdate=January 25, 2011 |author2=Bernard Kutter |date=September 2, 2010 |quote=''ACES design conceptualization has been underway at ULA for many years. It leverages design features of both the Centaur and Delta Cryogenic Second Stage (DCSS) upper stages and intends to supplement and perhaps replace these stages in the future. ...'' |deadurl=yes |archiveurl=https://web.archive.org/web/20111020010301/http://www.ulalaunch.com/site/docs/publications/DepotBasedTransportationArchitecture2010.pdf |archivedate=October 20, 2011 |df=mdy-all}}</ref>

===SLS Exploration Upper Stage===
In April 2016 it was reported NASA has chosen to use a design based on four RL10 engines for the [[Exploration Upper Stage]] to be used beginning with the crewed [[Exploration Mission 2|EM-2]] mission of the [[Space Launch System]].<ref>{{cite web |last=Bergin |first=Chris |title=MSFC propose Aerojet Rocketdyne supply EUS engines |url=https://www.nasaspaceflight.com/2016/04/msfc-aerojet-rocketdyne-eus-engines/ |work=[[NASASpaceFlight.com]] |accessdate=April 8, 2016 |date=April 7, 2016}}</ref> In October 2016 NASA confirmed these reports when it announced that the [[Exploration Upper Stage]] would utilize a new variant of the engine identified as the RL10C-3.<ref>{{cite web |title=Proven Engine Packs Big, In-Space Punch for NASA’s SLS Rocket |url=https://www.nasa.gov/exploration/systems/sls/proven-engine-packs-big-in-space-punch-for-nasa-s-sls-rocket.html |publisher=NASA |accessdate=November 22, 2017 |date=October 21, 2016}}</ref>

===Vulcan Centaur Upper Stage===
On May 11, 2018 United Launch Alliance (ULA) announced that Aerojet Rocketdyne would be strategic partner with their RL10C-X upper stage engine for ULA’s next-generation Vulcan Centaur rocket following a competitive procurement process.<ref>{{cite web |title=United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine |url=https://www.ulalaunch.com/about/news/2018/05/11/united-launch-alliance-selects-aerojet-rocketdyne-s-rl10-engine-for-next-generation-vulcan-centaur-upper-stage |publisher=ULA |accessdate=May 13, 2018 |date=May 11, 2018}}</ref>

==Variants==
{| class="sortable wikitable"
! Version
! Status
! First flight
! Dry mass
! Thrust
! [[Specific impulse|''I''sp (<math>v_\text{e}</math>), vac]]
! Length
! Diameter
! [[Thrust-to-weight ratio|T:W]]
! O:F
! [[Expansion ratio]]
! Chamber pressure
! Burn time
! Associated stage
! Notes
|-
| RL10A-1
| Retired
| 1962
| {{cvt|131|kg}}
| {{cvt|15000|lbf|kN|order=flip}}
| {{cvt|425|isp}}
| {{cvt|1.73|m}}
| {{cvt|1.53|m}}
| 52:1
|
| 40:1
|
| 430 s
| [[Centaur (rocket stage)|Centaur A]]
| Prototype <ref name="EA10A1">{{cite web |url=http://www.astronautix.com/engines/rl10a1.htm |title=RL-10A-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115155200/http://www.astronautix.com/engines/rl10a1.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref><ref name="S2S"/><ref name="GSPAC">{{cite web |url=http://space.skyrocket.de/doc_lau/atlas_centaur.htm |title=Atlas Centaur |publisher=Gunter's Space Page |accessdate=February 29, 2012}}</ref>
|-
| RL10A-3
| Retired
| 1963
| {{cvt|131|kg}}
| {{cvt|65.6|kN}}
| {{cvt|444|isp}}
| {{cvt|2.49|m}}
| {{cvt|1.53|m}}
| 51:1
| 5:1
| 57:1
| {{cvt|32.75|bar}}
| 470 s
| [[Centaur (rocket stage)|Centaur]] B/C/D/E [[S-IV]]
| <ref name="EA10A3">{{cite web |url=http://www.astronautix.com/engines/rl10a3.htm |title=RL-10A-3 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111206225154/http://www.astronautix.com/engines/rl10a3.htm |archivedate=December 6, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4
| Retired
| 1992
| {{cvt|168|kg}}
| {{cvt|92.5|kN}}
| {{cvt|449|isp}}
| {{cvt|2.29|m}}
| {{cvt|1.17|m}}
| 56:1
| 5.5:1
| 84:1
|
| 392 s
| [[Centaur (rocket stage)|Centaur IIA]]
| <ref name="EA10A4">{{cite web |url=http://www.astronautix.com/engines/rl10a4.htm |title=RL-10A-4 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115172045/http://www.astronautix.com/engines/rl10a4.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-1
| Retired
| 2000
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.53|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIA]]
| <ref name="EA10A41">{{cite web |url=http://www.astronautix.com/engines/rl10a41.htm |title=RL-10A-4-1 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111117134046/http://www.astronautix.com/engines/rl10a41.htm |archivedate=November 17, 2011 |df=mdy-all}}</ref>
|-
| RL10A-4-2 {{Clarify|date=May 2016}}
| In production
| 2002
| {{cvt|167|kg}}
| {{cvt|99.1|kN}}
| {{cvt|451|isp}}
|
| {{cvt|1.17|m}}
| 61:1
|
| 84:1
|
| 740 s
| [[Centaur (rocket stage)|Centaur IIIB]] Centaur V1 Centaur V2
| <ref name="EA10A42">{{cite web |url=http://www.astronautix.com/engines/rl10a42.htm |title=RL-10A-4-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120130143126/http://www.astronautix.com/engines/rl10a42.htm |archivedate=January 30, 2012 |df=mdy-all}}</ref><ref name=":0" />
|-
| RL10A-5
| Retired
| 1993
| {{cvt|143|kg}}
| {{cvt|64.7|kN}}
| {{cvt|373|isp}}
| {{cvt|1.07|m}}
| {{cvt|1.02|m}}
| 46:1
| 6:1
| 4:1
|
| 127 s
| [[McDonnell Douglas DC-X|DC-X]]
| <ref name="EA10A5">{{cite web |url=http://www.astronautix.com/engines/rl10a5.htm |title=RL-10A-5 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115141830/http://www.astronautix.com/engines/rl10a5.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| RL10B-2
| In production
| 1998
| {{cvt|277|kg}}
| {{cvt|110|kN}}
| {{cvt|462|isp}}
| {{cvt|4.14|m}}
| {{cvt|2.13|m}}
| 40:1
| 5.88:1
| 280:1
| {{cvt|44.12|bar}}
| 5m: 1,125 s 4m: 700 s
| [[Delta Cryogenic Second Stage]]
| <ref name="EA10B2">{{cite web |url=http://www.astronautix.com/engines/rl10b2.htm |title=RL-10B-2 |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm |archivedate=February 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|title=Delta IV Launch Services User's Guide, June 2013|url=https://www.ulalaunch.com/docs/default-source/rockets/delta-iv-user's-guide.pdf|website=ULA Launch|accessdate=15 March 2018}}</ref>
|-
| RL10B-X
| Cancelled
|
| {{cvt|317|kg}}
| {{cvt|93.4|kN}}
| {{cvt|470|isp}}
|
| {{cvt|1.53|m}}
| 30:1
|
| 250:1
|
| 408 s
| [[Centaur (rocket stage)|Centaur B-X]]
| <ref name="EA10BX">{{cite web |url=http://www.astronautix.com/engines/rl10bx.htm |title=RL-10B-X |work=Encyclopedia Astronautica |first=Mark |last=Wade |accessdate=February 27, 2012 |date=November 17, 2011 |deadurl=yes |archiveurl=https://web.archive.org/web/20111115150728/http://www.astronautix.com/engines/rl10bx.htm |archivedate=November 15, 2011 |df=mdy-all}}</ref>
|-
| CECE
| Demonstrator project
|
| {{cvt|160|kg}}
| {{cvt|15000|lbf|kN|order=flip}}, throttle to 5–10%
| >{{cvt|445|isp}}
| {{cvt|1.53|m}}
|
|
|
|
|
|
|
| <ref name="PWRCECE">{{cite web |url=http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |title=Commons Extensible Cryogenic Engine |publisher=Pratt & Whitney Rocketdyne |accessdate=February 28, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120304081145/http://www.pw.utc.com/products/pwr/propulsion_solutions/cece.asp |archivedate=March 4, 2012 |df=mdy-all}}</ref><ref>{{cite web|url=http://www.rocket.com/common-extensible-cryogenic-engine|title=Common Extensible Cryogenic Engine - Aerojet Rocketdyne|author=|date=|website=www.rocket.com|accessdate=April 8, 2018}}</ref>
|-
| RL10C-1 {{Clarify|date=May 2016}}
| In production
| 2014
| {{cvt|420|lb|order=flip}}
| {{cvt|22890|lbf|kN|order=flip}}
| {{cvt|449.7|isp}}
| {{cvt|2.22|m}}
| {{cvt|1.44|m}}
| 57:1
| 5.5:1
| 130:1
|
| 2000 s
| Centaur SEC
| <ref name="CPS">{{cite web |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015783.pdf |title=Cryogenic Propulsion Stage |publisher=NASA |accessdate=October 11, 2014}}</ref><ref>{{cite web|url=http://forum.nasaspaceflight.com/index.php?topic=34891.0|title=Atlas-V with RL10C powered Centaur|author=|date=|website=forum.nasaspaceflight.com|accessdate=April 8, 2018}}</ref><ref>{{cite web |title=Evolution of Pratt & Whitney's cryogenic rocket engine RL-10 |url=http://b14643.de/Spacerockets/Diverse/P&W_RL10_engine/index.htm |accessdate=February 20, 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20160303141931/http://b14643.de/Spacerockets/Diverse/P%26W_RL10_engine/index.htm |archivedate=March 3, 2016 |df=mdy-all }}</ref><ref name=":0">{{cite web |title=RL10 Engine |url=http://www.rocket.com/rl10-engine |publisher=Aerojet Rocketdyne}}</ref>
|}

==Specifications==

===Original RL10===
[[File:RL-10 rocket engine.jpg|thumb|300px]]
* Thrust (altitude): 15,000 [[Pound-force|lbf]] (66.7 kN)<ref name="S2S">{{cite book |url=https://history.nasa.gov/SP-4206/ch5.htm |title=Stages to Saturn; A Technological History of the Apollo/Saturn Launch Vehicles |chapter=Unconventional Cryogenics: RL-10 and J-2 |publisher=NASA History Office |location=Washington, D.C. |first=Roger E. |last=Bilstein |date=1996 |accessdate=December 2, 2011}}</ref>
* Burn Time: 470 s
* Design: [[Expander cycle]]
* [[Specific impulse]]: {{convert|433|isp}}
* Engine weight—[[dry weight|dry]]: 298 lb (135 kg)
* Height: 68 in (1.73 m)
* Diameter: 39 in (0.99 m)
* Nozzle expansion ratio: 40 to 1
* Propellants: Liquid Oxygen & Liquid Hydrogen
* Propellant flow: 35 lb/s (16 kg/s)
* Contractor: Pratt & Whitney
* Vehicle application: [[Saturn I]] / [[S-IV]] 2nd stage—6-engines
* Vehicle application: [[Centaur (rocket stage)|Centaur]] upper stage—2-engines

===Current design===
[[File:Second stage of a Delta IV Medium rocket.jpg|thumb|Second stage of a Delta IV Medium rocket featuring an RL10B-2 engine]]

; RL10B-2 Specifications
*Thrust (altitude): 24,750 lbf (110.1 kN)<ref name=pwr_rl10b-2.pdf>{{cite web |url=http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |title=RL10B-2 |publisher=[[Pratt & Whitney Rocketdyne]] |date=2009 |accessdate=January 29, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120326211303/http://www.pw.utc.com/products/pwr/assets/pwr_rl10b-2.pdf |archivedate=March 26, 2012 |df=mdy-all }}</ref>
*Design: [[Expander cycle]]<ref name="Sutton1998">{{cite journal |url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA397948 |title=50K expander cycle engine demonstration |journal=AIP Conference Proceedings |first1=A. M. |last1=Sutton |first2=S. D. |last2=Peery |first3=A. B. |last3=Minick |volume=420 |pages=1062–1065 |date=January 1998 |doi=10.1063/1.54719}}</ref>
*[[Specific impulse]]: {{convert|464|isp}}<ref name=pwr_rl10b-2.pdf />
*Engine weight - dry: 610 lb (277 kg)<ref name=pwr_rl10b-2.pdf />
*Height: 163 in (4.14 m)<ref name=pwr_rl10b-2.pdf />
*Diameter: 87 in (2.21 m)<ref name=pwr_rl10b-2.pdf />
*Expansion ratio: 280 to 1
*Mixture ratio: 5.88 to 1 <ref name=pwr_rl10b-2.pdf />
*Propellants: [[Liquid oxygen]] & [[liquid hydrogen]]<ref name=pwr_rl10b-2.pdf />
*Propellant flow: Oxidizer 41.42 lb/s (20.6 kg/s), fuel 7.72 lb/s (3.5 kg/s)<ref name=pwr_rl10b-2.pdf />
*Contractor: Pratt & Whitney
*Vehicle application: [[Delta III]], Delta IV second stage (1 engine)

; RL10A-4-2
The other current model, the RL10A-4-2, is the engine used on [[Centaur (rocket stage)|Centaur]] upper stage for [[Atlas V]].<ref name=pwr_rl10b-2.pdf />

==Possible successor==
In 2012 NASA joined with the US Air Force (USAF) to study next-generation upper stage propulsion, formalizing the agencies joint interests in a new upper stage engine to replace the Aerojet Rocketdyne RL10.
{{quote|"We know the list price on an RL10. If you look at cost over time, a very large portion of the unit cost of the EELVs is attributable to the propulsion systems, and the RL10 is a very old engine, and there's a lot of craftwork associated with its manufacture. ... That's what this study will figure out, is it worthwhile to build an RL10 replacement?"|author=Dale Thomas, Associated Director Technical, Marshall Space Flight Center<ref name=FG2012/>}}

From the study, NASA hopes to find a less expensive RL10-class engine for a third stage of the [[Space Launch System]] (SLS).<ref name=FG2012/><ref name=NASA-2012-04/>

USAF hopes to replace the Rocketdyne RL10 engines used on the upper stage of both the Lockheed Martin Atlas V and the Boeing Delta IV, known as [[Evolved Expendable Launch Vehicle]]s (EELV), that are the primary methods of putting US government satellites into space.<ref name=FG2012>{{cite web |last=Roseberg |first=Zach |title=NASA, US Air Force to study joint rocket engine |url=http://www.flightglobal.com/news/articles/nasa-us-air-force-to-study-joint-rocket-engine-370660/ |publisher=Flight Global |accessdate=June 1, 2012 |date=April 12, 2012}}</ref> This relates to the requirements study of the [[Affordable Upper Stage Engine Program]] (AUSEP) liquid rocket engine for use on upper stages of medium- and heavy-class launch vehicles, including the Evolved Expendable Launch Vehicle (EELV) family of launch vehicles.<ref name=NASA-2012-04>{{cite web |url=https://www.nasa.gov/centers/marshall/news/news/releases/2012/12-040.html |title=NASA Partners With U.S. Air Force to Study Common Rocket Propulsion Challenges |publisher=NASA |first=Kimberly |last=Newton |date=April 12, 2012}}</ref>

==Engines on display==
* An RL10 is on display at the [[New England Air Museum]], [[Windsor Locks, Connecticut]]<ref>{{cite web |url=http://neam.org/index.php?option=com_content&view=article&id=1112 |title=Pratt & Whitney RL10A-1 Rocket Engine |work=New England Air Museum |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], [[Chicago]], [[Illinois]]<ref name="histspace">{{cite web |url=http://historicspacecraft.com/rocket_engines.html |title=Photos of Rocket Engines |work=Historic Spacecraft |accessdate=April 26, 2014}}</ref>
* An RL10 is on display at the [[U.S. Space & Rocket Center]], [[Huntsville, Alabama]]<ref name="histspace"/>
* An RL10 is on display at [[Southern University]], [[Baton Rouge, Louisiana]]<ref>{{cite press release |url=http://www.prnewswire.com/news-releases/pratt--whitney-rocketdyne-donates-model-of-legendary-rl10-rocket-engine-to-southern-university-55982567.html |title=Pratt & Whitney Rocketdyne Donates Model of Legendary Rl10 Rocket Engine to Southern University |agency=PR Newswire |publisher=Pratt & Whitney Rocketdyne |first1=Nancy |last1=Colaguori |first2=Bryan |last2=Kidder |date=November 3, 2006 |accessdate=April 26, 2014}}</ref>
* Two RL10 engines are on display at [[US Space Walk of Fame]], [[Titusville, Florida]]<ref>{{cite web|url=https://www.facebook.com/SpaceWalkOfFame/photos/pcb.10152534325180820/10152534320660820/?type=1&theater|title=American Space Museum & Space Walk of Fame|author=|date=|website=www.facebook.com|accessdate=April 8, 2018}}</ref>
* An RL10 is on display in the Aerospace Engineering Department, Davis Hall at [[Auburn University]].{{cn|date=April 2017}}
* An RL10A-4 is on display at the Science Museum in London, UK.

==See also==
*[[Spacecraft propulsion]]
*[[RL60]]
*[[RD-0146]]
*[[XCOR Aerospace#ULA liquid hydrogen large engine development project|XCOR/ULA aluminum alloy nozzle engine]], under development in 2011

==References==
{{Reflist|30em}}

==Bibliography==
* {{cite book |last=Connors |first=Jack |title=The Engines of Pratt & Whitney: A Technical History |publisher=[[American Institute of Aeronautics and Astronautics]] |location=Reston. Virginia |date=2010 |isbn=978-1-60086-711-8 |url=}}

==External links==
{{Commons category|RL10 (rocket engine)|RL10}}
*[https://web.archive.org/web/20120204144940/http://www.astronautix.com/engines/rl10b2.htm RL10B-2 at Astronautix]
*[http://www.spaceflightnow.com/news/n0708/16rl10valve/ Spaceflight Now article]
*[http://www.spaceflightnow.com/news/n0901/26altair/ Spaceflight Now article]

{{Rocket engines}}
{{Atlas rockets}}
{{Thor and Delta rockets}}

[[Category:Rocket engines using hydrogen propellant]]
[[Category:North American Aviation]]
[[Category:Rocket engines using the expander cycle]]

OmegA

2018-04-17T23:58:28Z

Blastr42: /* Multiple configurations */

{{Infobox rocket
|name = Omega
|manufacturer = [[Orbital ATK]]
|country-origin = United States
|height = {{convert|59.84|m|ft}}
|diameter = {{convert|3.71|m|ft}} first stage {{convert|5.25|m|ft}} upper stage
|mass =
|stages = 3
|capacities =
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="oatk20180221>{{cite web|title=Orbital ATK Next Generation Launch System Completes Major Milestones|url=https://www.orbitalatk.com/news-room/insideOA/NGL/default.aspx|website=Orbital ATK|accessdate=17 April 2018|date=21 February 2018}}</ref>
}}
{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="oatk20180221" />
}}
|family = [[Shuttle-Derived Launch Vehicle]]
|derivatives = 
|comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
|status = Under Development
|sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]]
|launches = 0
|success = 0
|fail = 0
|partial = 0
|first= 2021 (projected)
|stagedata =
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name = [[Graphite-Epoxy Motor|GEM-63 or GEM-63XL]]
|number = 0 to 6
|diameter = {{convert|63|in|m|order=flip|abbr=on}}
|solid = yes
|total = 
|SI = {{convert|279.3|isp}}
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = First
|engines = Castor 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Second
|engines = Castor 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Third
|engines = 2 × [[RL-10|RL-10C-5-1]]
|thrust = {{convert|22890|lbf|kN|order=flip}}
|SI = ~450 seconds (vacuum)
|burntime = unknown
|fuel = [[LOX]]/[[LH2]]
}}
}}
'''Omega''', stylized as "'''OmegA'''" is a [[launch vehicle]] in development by [[Orbital ATK]] as an [[Evolved Expendable Launch Vehicle|EELV]] replacement program intended for national security and commercial satellites.<ref>{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have combine a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne Holdings|Aerojet Rocketdyne]]<ref>{{Cite news|url=http://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/|title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket - SpaceNews.com|date=2018-04-16|work=SpaceNews.com|access-date=2018-04-17|language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spaceflightnow.com/2016/05/27/details-of-orbital-atks-proposed-heavy-launcher-revealed/|title=Details of Orbital ATK’s proposed heavy launcher revealed |publisher= Spaceflight Now|first=Stephen|last=Clark|date=27 May 2016}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[Geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development is awaiting a funding decision by the USAF.

==History==
[[File: Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, Orbital ATK was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5-6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher is planned to take place between late 2017 and early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{update after|2017|12}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). NGL would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL-10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor.<ref>{{cite web|title=Orbital ATK Twitter|url=https://twitter.com/OrbitalATK/status/986030002213879808|website=Twitter|accessdate=17 April 2018|date=17 April 2018}}</ref> The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}}.<ref name="oatk20180221" />

==Multiple configurations==
The basic configuration of four-segment [[solid rocket booster]] (SRB) with cryogenic upper stage, expands to baseline configuration of 2-segment first stage solid booster, with a 2-segment second stage solid booster, and third stage cryogenic booster. Also a heavy configuration adds a 4-segment first stage replacing the 2-segment booster of the baseline version. Additional versions are projected to add additional SRBs as side boosters. The SDLV SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs. Additional savings may be realized by replacing SLS' steel-cased SRBs with composite ones from Omega.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }} </ref>

==References==
{{Reflist|2}}

==External links==
*[https://www.orbitalatk.com/flight-systems/space-launch-vehicles/OmegA/default.aspx OmegA official web site]

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

{{S-start}}
{{Succession box
| title = Single-stick SRB-based SDLV
| years = 2016-
| before = [[Liberty (rocket)|Liberty]]
| after = N/A CURRENT
}}
{{S-end}}

{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

OmegA

2018-04-17T23:13:45Z

Blastr42:

{{Infobox rocket
|name = Omega
|manufacturer = [[Orbital ATK]]
|country-origin = United States
|height = {{convert|59.84|m|ft}}
|diameter = {{convert|3.71|m|ft}} first stage {{convert|5.25|m|ft}} upper stage
|mass =
|stages = 3
|capacities =
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = Intermediate: {{convert|4900|kg|lb}} to {{convert|10100|kg|lb}}<ref name="oatk20180221>{{cite web|title=Orbital ATK Next Generation Launch System Completes Major Milestones|url=https://www.orbitalatk.com/news-room/insideOA/NGL/default.aspx|website=Orbital ATK|accessdate=17 April 2018|date=21 February 2018}}</ref>
}}
{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = Heavy: {{convert|5250|kg|lb}} to {{convert|7800|kg|lb}}<ref name="oatk20180221" />
}}
|family = [[Shuttle-Derived Launch Vehicle]]
|derivatives = 
|comparable = {{flatlist|
* [[Falcon Heavy]]
* [[Delta IV Heavy]]
* [[Long March 5]]
* [[New Glenn]]
* [[Saturn C-3]]
* [[Vulcan (rocket)|Vulcan]]}}
Preceded by [[Liberty (rocket)|Liberty]]
|status = Under Development
|sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]]
|launches = 0
|success = 0
|fail = 0
|partial = 0
|first= 2021 (projected)
|stagedata =
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name = [[Graphite-Epoxy Motor|GEM-63 or GEM-63XL]]
|number = 0 to 6
|diameter = {{convert|63|in|m|order=flip|abbr=on}}
|solid = yes
|total = 
|SI = {{convert|279.3|isp}}
|fuel = [[HTPB]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = First
|engines = Castor 600 (Intermediate) or Castor 1200 (Heavy) [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Second
|engines = Castor 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]
}}
{{Infobox rocket/Stage
|type = stage
|stageno = Third
|engines = 2 × [[RL-10|RL-10C-5-1]]
|thrust = {{convert|22890|lbf|kN|order=flip}}
|SI = ~450 seconds (vacuum)
|burntime = unknown
|fuel = [[LOX]]/[[LH2]]
}}
}}
'''Omega''', stylized as "'''OMEGA'''" is a [[launch vehicle]] in development by [[Orbital ATK]] as an [[Evolved Expendable Launch Vehicle|EELV]] replacement program intended for national security and commercial satellites.<ref>{{cite web|title=Orbital ATK|url=https://twitter.com/OrbitalATK/status/986029298195759105|website=Twitter|accessdate=17 April 2018}}</ref>

Omega is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have combine a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Omega consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by [[Aerojet Rocketdyne Holdings|Aerojet Rocketdyne]]<ref>{{Cite news|url=http://spacenews.com/orbital-atk-selects-aerojet-rocketdynes-rl10c-for-newly-christened-omega-rocket/|title=Orbital ATK selects Aerojet Rocketdyne's RL10C for newly christened OmegA rocket - SpaceNews.com|date=2018-04-16|work=SpaceNews.com|access-date=2018-04-17|language=en-US}}</ref> (replacing earlier plans to use an upper stage provided by [[Blue Origin]]).<ref name="YahooFinance-20160524">{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spaceflightnow.com/2016/05/27/details-of-orbital-atks-proposed-heavy-launcher-revealed/|title=Details of Orbital ATK’s proposed heavy launcher revealed |publisher= Spaceflight Now|first=Stephen|last=Clark|date=27 May 2016}}</ref>

Omega is proposed as a vehicle to launch national security satellites for the United States Air Force, and could launch other government and commercial payloads, including to [[Geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

Development is awaiting a funding decision by the USAF.

==History==
[[File: Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, Orbital ATK was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract would fund the development of three technologies in support of the Omega rocket, then called Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5-6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher is planned to take place between late 2017 and early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>{{update after|2017|12}}

In April 2017, Orbital ATK revealed that Omega would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). NGL would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages.<ref name=FloridaToday-2017-04-06/>

In April 2018, Orbital ATK announced that Next Generation Launcher would be named Omega. Additionally, they revealed the selection of the [[RL-10|RL-10C]] engine over Blue Origin's [[BE-3|BE-3U]] competitor.<ref>{{cite web|title=Orbital ATK Twitter|url=https://twitter.com/OrbitalATK/status/986030002213879808|website=Twitter|accessdate=17 April 2018|date=17 April 2018}}</ref> The Intermediate configuration, with a Castor 600 first stage, increased payload to GTO from {{convert|8500|kg|lb}} to {{convert|10100|kg|lb}}. The Castor 1200-powered Heavy configuration increased GEO payload from {{convert|7000|kg|lb}} to {{convert|7800|kg|lb}}.<ref name="oatk20180221" />

==Multiple configurations==
The basic configuration of four-segment [[solid rocket booster]] (SRB) with cryogenic upper stage, expands to baseline configuration of 2-segment first stage solid booster, with a 2-segment second stage solid booster, and third stage cryogenic booster. Also a heavy configuration adds a 4-segment first stage replacing the 2-segment booster of the baseline version. Additional versions are projected to add additional SRBs as side boosters. The SDLV SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs. Additional savings may be realized by homologating the SLS SRBs with NGL, replacing SLS' steel-cased SRBs with composite ones.<ref name=FloridaToday-2017-04-06>{{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }} </ref>

==References==
{{Reflist|2}}

==External links==
*[https://www.orbitalatk.com/flight-systems/space-launch-vehicles/OmegA/default.aspx OmegA official web site]

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a [[Saturn V]]-derived [[J-2X]] based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and [[Ariane 5]]-derived [[Vulcain|Vulcain 2]] based second stage

{{S-start}}
{{Succession box
| title = Single-stick SRB-based SDLV
| years = 2016-
| before = [[Liberty (rocket)|Liberty]]
| after = N/A CURRENT
}}
{{S-end}}

{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

Soyuz-2-1v

2018-03-30T15:59:25Z

Blastr42: /* Operational History */Added reference for Mar 2018 launch

{{distinguish|Soyuz-2.1a|Soyuz-2.1b}}
{{Infobox Rocket
|name = Soyuz-2-1v
|image = Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take1.JPG
|imsize = 180px
|caption = A small-scale model of the Soyuz-2-1v rocket exhibited at the [[Paris Air Show]] in 2011
|function = Light carrier rocket
|manufacturer = [[Progress State Research and Production Rocket Space Center|TsSKB Progress]]
|country-origin = Russia
|height = {{convert|44|m}}
|diameter = {{convert|3|m}}
|mass = {{convert|158000|kg}}
|stages = 2
|capacities =
{{Infobox Rocket/Payload
|location = 200km x 51.8° [[Low Earth orbit|LEO]]
|kilos = {{convert|2850|kg}}
}}
{{Infobox Rocket/Payload
|location = 200km x 62.8° [[Low Earth orbit|LEO]]
|kilos = {{convert|2800|kg}}
}}
|family = [[R-7 (rocket family)|R-7]]/[[Soyuz (rocket family)|Soyuz]]/[[Soyuz-2 (rocket)|2]]
|comparable = [[Long March 2C]] [[PSLV]]
|status = Active
|sites = [[Baikonur Cosmodrome|Baikonur]] Sites [[Gagarin's Start|1/5]] & [[Baikonur Cosmodrome Site 31|31/6]] [[Plesetsk Cosmodrome|Plesetsk]] [[Plesetsk Cosmodrome Site 43|Site 43]] [[Vostochny Cosmodrome|Vostochny]]
|launches = 4
|success = 3
|fail = 
|partial = 1
|first = 28 December 2013
|last = 29 March 2018
}}
The '''Soyuz-2-1v''' ({{lang-ru|'''Союз 2.1в'''}}, ''Union 2.1v''), [[GRAU index]] '''14A15''',<ref>{{cite web |publisher= [[Plesetsk Cosmodrome|Plesetsk]] | accessdate= 30 December 2013 |url=http://www.plesetzk.ru/rn/rus |title=Rus/Souyz-2 launch vehicle | language = Russian}}</ref> known earlier in development as the '''Soyuz-1''' ({{lang-ru|'''Союз 1'''}}, ''Union 1''), is a [[Russian Federation|Russian]] [[expendable launch system|expendable]] [[launch vehicle|carrier rocket]]. It was derived from the [[Soyuz-2 (rocket)|Soyuz-2.1b]], and is a member of the [[R-7 (rocket family)|R-7 family]] of rockets. It is built by [[Progress State Research and Production Rocket Space Center|TsSKB Progress]], at [[Samara, Russia|Samara]] in the [[Russian Federation]]. Launches are conducted from existing facilities at the [[Plesetsk Cosmodrome]] in Northwest Russia, with pads also available at the [[Baikonur Cosmodrome]] in [[Kazakhstan]],<ref name="Samara">{{cite web|url=http://www.samspace.ru/ENG/RN/souz_1.htm|title="Soyuz-1" middle class launch vehicle|publisher=Samara Space Centre|accessdate=11 April 2009}}</ref> and new facilities at the [[Vostochny Cosmodrome]] in Eastern Russia.<ref>{{cite web|url=http://rbth.co.uk/science_and_tech/2013/07/24/vostochny_cosmodrome_clears_the_way_to_deep_space_28345.html | publisher = Russia Beyond The Headlines | accessdate = 30 December 2013 | title = Vostochny Cosmodrome clears the way to deep space | date = 24 July 2013 | first = Alexander | last = Peslyak}}</ref>

==Vehicle==
The Soyuz-2-1v represents a major departure from earlier [[Soyuz (rocket family)|Soyuz]] rockets. Unlike the Soyuz-2-1b upon which it is based, it omits the four boosters used on all other [[R-7 (rocket family)|R-7]] vehicles. The first stage of the Soyuz-2-1v is a heavily modified derivative of the Soyuz-2 first stage, with a single-chamber [[NK-33]] engine replacing the four-chamber [[RD-117]] used on previous rockets along with structural modifications to the stage and lower tanking. Since the NK-33 is fixed, the [[RD-0110R]] engine is used to supply thrust vector control. It also supplies an extra {{convert|230.5|kN|lbf}}<ref name=kbkha-rd0110r /> of thrust and heats the pressurization gases.<ref name=kbkha-rd0110r>{{cite web |url=http://www.kbkha.ru/?p=8&cat=8&prod=74 |title= Steering engine RD0110R (14D24). Carrier rocket "Soyuz-2-1v" |publisher=KBKhA |language=Russian |accessdate=1 June 2015}}</ref>

The [[NK-33]] engine, originally built for the [[N1 (rocket)|N1]] programme, offers increased performance over the RD-117; however, only a limited number of engines are available. Once the supply is exhausted, the NK-33 will be replaced by the [[RD-193]]. In April 2013, it was announced that the RD-193 engine had completed testing. The RD-193 is a lighter and shorter engine based on the [[Angara (rocket family)|Angara]]'s [[RD-191]], which is itself a derivative of the [[Zenit (rocket family)|Zenit]]'s [[RD-170]].<ref>{{cite web|title=New engine for light rocket "Soyuz" prepare for mass production at the end of the year|url=http://www.novosti-kosmonavtiki.ru/news/7229/|publisher=Новости космонавтики|accessdate=8 April 2013|language=Russian}}</ref>

The second stage of the Soyuz-2-1v is the same as the third stage of the Soyuz-2-1b;<ref>{{cite web|url=http://www.russianspaceweb.com/soyuz1_lv_origin.html|title=Development of Soyuz-1|first=Anatoly|last=Zak|work=RussianSpaceWeb|accessdate=30 December 2013}}</ref> powered by an [[RD-0124]] engine. For most missions a [[Volga (rocket stage)|Volga]] upper stage will be used to manoeuvre the payload from an initial parking orbit to its final destination. The Volga is derived from the propulsion system of the [[Yantar (satellite)|Yantar]] reconnaissance satellite, and was developed as a lighter and cheaper alternative to the [[Fregat]].

The Soyuz-2-1v was designed as a light-class carrier rocket, and has a payload capacity of {{convert|2850|kg}} to a {{convert|200|km|sing=on}} circular [[low Earth orbit]] with an [[inclination]] of 56.8° from Baikonur, and {{convert|2800|kg}} to a 200 kilometre orbit at 62.8° from Plesetsk.<ref name="Samara"/>

==Operational History==
In 2009, the maiden flight of the Soyuz-2-1v was announced as being scheduled for 2010, with this later being delayed to 2011 and then 2012 by development delays and payload availability. By June 2011 it was scheduled to occur at the end of 2012. During a test firing of a first stage prototype in August 2012, a test stand software malfunction resulted in damage to the stand and prototype, delaying the static testing programme.<ref>{{cite web|url=http://www.russianspaceweb.com/soyuz1_lv_development.html|title=Development of Soyuz-1|first=Anatoly|last=Zak|work=RussianSpaceWeb|accessdate=28 December 2013}}</ref>

The test was re-attempted in May 2013, and was declared successful despite the burn lasting 52 seconds shorter than had been expected. With this complete, the launch was scheduled for September 2013. It subsequently slipped to November and then December.<ref name="s101">{{cite web|url=http://www.spaceflight101.com/soyuz-2-1v.html|title=Soyuz 2-1v|publisher=Spaceflight 101|accessdate=28 December 2013}}</ref>

The maiden flight – which made use of a [[Volga (rocket stage)|Volga]] upper stage – carried the [[Aist 1]] microsatellite and a pair of [[SKRL-756]] calibration spheres. Ahead of the launch, the rocket was rolled out to [[Plesetsk Cosmodrome Site 43|Site 43/4]] at the [[Plesetsk Cosmodrome]] on 18 December 2013 with the launch scheduled for 23 December.<ref name="s101"/>

The launch was delayed beyond 23 December by problems found during late testing at the pad. An attempt to launch was made on 25 December, but it was scrubbed around ten minutes before the liftoff, which had been scheduled for 14:00 UTC. Despite reports that the launch could not take place before the end of the year, it was rescheduled for 10:30 UTC on 28 December.<ref>{{cite web|url=http://www.russianspaceweb.com/soyuz1_lv_aist.html|title=Soyuz-2-1v lifts off successfully|first=Anatoly|last=Zak|work=RussianSpaceWeb|accessdate=28 December 2013}}</ref> A further last-minute delay pushed the liftoff back to 12:30 UTC (16:30 local time), at which time the launch took place successfully.<ref>{{cite web|url=http://en.ria.ru/russia/20131228/186021089/After-Series-of-Delays-Russia-Launches-New-Soyuz-Rocket.html|title=After Series of Delays, Russia Launches New Soyuz Rocket|publisher=RIA Novosti|date=28 December 2013|accessdate=28 December 2013}}</ref> Spacecraft separation occurred 100 minutes later, at 14:10 UTC.<ref>{{cite web|url=http://www.nasaspaceflight.com/2013/12/russia-debut-soyuz-2-1v-plesetsk/|title= Russia conducts debut launch of Soyuz-2-1v|author=Nathaniel Downes and Chris Bergin|publisher=NASASpaceflight.com|accessdate=28 December 2013}}</ref>

The second launch of the vehicle on December 5, 2015 carried two payloads Kanopus-ST and KYuA-1, while the Kanopus-ST failed to separate from the final stage.<ref name="reuters">{{cite web|url=http://in.reuters.com/article/press-digest-russia-dec-idINL8N13W0U620151207|author=Reuters Editorial|title=PRESS DIGEST - RUSSIA - Dec 7|website=Reuters|accessdate=10 December 2017}}</ref><ref name="spaceflightinsider">{{cite web|url=http://www.spaceflightinsider.com/missions/defense/russia-successfully-launches-kanopus-st-satellite-into-orbit/|title=Russian Soyuz-2.1v launch a partial failure|website=SpaceFlight Insider|accessdate=10 December 2017}}</ref>

An unannounced launch carried a secret military payload on June 23, 2017.<ref>{{cite web |url=https://spaceflightnow.com/2017/06/23/secret-russian-satellite-launched-from-plesetsk-cosmodrome/ |title=Secret Russian satellite launched from Plesetsk Cosmodrome |last=Clark |first=Stephen |date=23 June 2017 |access-date=24 June 2017 }}</ref>

The next flight was on 29 March 2018.<ref>{{cite web |url=http://www.russianspaceweb.com/emka.html |title=Soyuz-2-1v launches a military payload |last=Zak |first=Anatoly |date=29 March 2018 |access-date=29 March 2018 }}</ref>

== Photogallery from Paris Air Show 2011 ==
Russia exhibited a model of the Soyuz-2-1v during the [[2011 Paris Air Show]] at [[Le Bourget]].
<gallery>
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take1.JPG|General view of the rocket
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take3.jpg|Second stage view
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take2.jpg|Detailed view of the payload section
</gallery>

==References==
{{reflist|30em}}

{{Expendable launch systems}}
{{Russian launch vehicles}}
{{R-7 rockets}}

{{Use British English|date=January 2014}}
{{Use dmy dates|date=January 2014}}

[[Category:R-7 (rocket family)]]
[[Category:Space launch vehicles of Russia]]
[[Category:2013 in spaceflight]]
[[Category:Vehicles introduced in 2013]]

[[ru:Союз-1 (ракета-носитель)]]

Soyuz-2-1v

2018-03-30T15:54:29Z

Blastr42: Updated with newest launched info

{{distinguish|Soyuz-2.1a|Soyuz-2.1b}}
{{Infobox Rocket
|name = Soyuz-2-1v
|image = Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take1.JPG
|imsize = 180px
|caption = A small-scale model of the Soyuz-2-1v rocket exhibited at the [[Paris Air Show]] in 2011
|function = Light carrier rocket
|manufacturer = [[Progress State Research and Production Rocket Space Center|TsSKB Progress]]
|country-origin = Russia
|height = {{convert|44|m}}
|diameter = {{convert|3|m}}
|mass = {{convert|158000|kg}}
|stages = 2
|capacities =
{{Infobox Rocket/Payload
|location = 200km x 51.8° [[Low Earth orbit|LEO]]
|kilos = {{convert|2850|kg}}
}}
{{Infobox Rocket/Payload
|location = 200km x 62.8° [[Low Earth orbit|LEO]]
|kilos = {{convert|2800|kg}}
}}
|family = [[R-7 (rocket family)|R-7]]/[[Soyuz (rocket family)|Soyuz]]/[[Soyuz-2 (rocket)|2]]
|comparable = [[Long March 2C]] [[PSLV]]
|status = Active
|sites = [[Baikonur Cosmodrome|Baikonur]] Sites [[Gagarin's Start|1/5]] & [[Baikonur Cosmodrome Site 31|31/6]] [[Plesetsk Cosmodrome|Plesetsk]] [[Plesetsk Cosmodrome Site 43|Site 43]] [[Vostochny Cosmodrome|Vostochny]]
|launches = 4
|success = 3
|fail = 
|partial = 1
|first = 28 December 2013
|last = 29 March 2018
}}
The '''Soyuz-2-1v''' ({{lang-ru|'''Союз 2.1в'''}}, ''Union 2.1v''), [[GRAU index]] '''14A15''',<ref>{{cite web |publisher= [[Plesetsk Cosmodrome|Plesetsk]] | accessdate= 30 December 2013 |url=http://www.plesetzk.ru/rn/rus |title=Rus/Souyz-2 launch vehicle | language = Russian}}</ref> known earlier in development as the '''Soyuz-1''' ({{lang-ru|'''Союз 1'''}}, ''Union 1''), is a [[Russian Federation|Russian]] [[expendable launch system|expendable]] [[launch vehicle|carrier rocket]]. It was derived from the [[Soyuz-2 (rocket)|Soyuz-2.1b]], and is a member of the [[R-7 (rocket family)|R-7 family]] of rockets. It is built by [[Progress State Research and Production Rocket Space Center|TsSKB Progress]], at [[Samara, Russia|Samara]] in the [[Russian Federation]]. Launches are conducted from existing facilities at the [[Plesetsk Cosmodrome]] in Northwest Russia, with pads also available at the [[Baikonur Cosmodrome]] in [[Kazakhstan]],<ref name="Samara">{{cite web|url=http://www.samspace.ru/ENG/RN/souz_1.htm|title="Soyuz-1" middle class launch vehicle|publisher=Samara Space Centre|accessdate=11 April 2009}}</ref> and new facilities at the [[Vostochny Cosmodrome]] in Eastern Russia.<ref>{{cite web|url=http://rbth.co.uk/science_and_tech/2013/07/24/vostochny_cosmodrome_clears_the_way_to_deep_space_28345.html | publisher = Russia Beyond The Headlines | accessdate = 30 December 2013 | title = Vostochny Cosmodrome clears the way to deep space | date = 24 July 2013 | first = Alexander | last = Peslyak}}</ref>

==Vehicle==
The Soyuz-2-1v represents a major departure from earlier [[Soyuz (rocket family)|Soyuz]] rockets. Unlike the Soyuz-2-1b upon which it is based, it omits the four boosters used on all other [[R-7 (rocket family)|R-7]] vehicles. The first stage of the Soyuz-2-1v is a heavily modified derivative of the Soyuz-2 first stage, with a single-chamber [[NK-33]] engine replacing the four-chamber [[RD-117]] used on previous rockets along with structural modifications to the stage and lower tanking. Since the NK-33 is fixed, the [[RD-0110R]] engine is used to supply thrust vector control. It also supplies an extra {{convert|230.5|kN|lbf}}<ref name=kbkha-rd0110r /> of thrust and heats the pressurization gases.<ref name=kbkha-rd0110r>{{cite web |url=http://www.kbkha.ru/?p=8&cat=8&prod=74 |title= Steering engine RD0110R (14D24). Carrier rocket "Soyuz-2-1v" |publisher=KBKhA |language=Russian |accessdate=1 June 2015}}</ref>

The [[NK-33]] engine, originally built for the [[N1 (rocket)|N1]] programme, offers increased performance over the RD-117; however, only a limited number of engines are available. Once the supply is exhausted, the NK-33 will be replaced by the [[RD-193]]. In April 2013, it was announced that the RD-193 engine had completed testing. The RD-193 is a lighter and shorter engine based on the [[Angara (rocket family)|Angara]]'s [[RD-191]], which is itself a derivative of the [[Zenit (rocket family)|Zenit]]'s [[RD-170]].<ref>{{cite web|title=New engine for light rocket "Soyuz" prepare for mass production at the end of the year|url=http://www.novosti-kosmonavtiki.ru/news/7229/|publisher=Новости космонавтики|accessdate=8 April 2013|language=Russian}}</ref>

The second stage of the Soyuz-2-1v is the same as the third stage of the Soyuz-2-1b;<ref>{{cite web|url=http://www.russianspaceweb.com/soyuz1_lv_origin.html|title=Development of Soyuz-1|first=Anatoly|last=Zak|work=RussianSpaceWeb|accessdate=30 December 2013}}</ref> powered by an [[RD-0124]] engine. For most missions a [[Volga (rocket stage)|Volga]] upper stage will be used to manoeuvre the payload from an initial parking orbit to its final destination. The Volga is derived from the propulsion system of the [[Yantar (satellite)|Yantar]] reconnaissance satellite, and was developed as a lighter and cheaper alternative to the [[Fregat]].

The Soyuz-2-1v was designed as a light-class carrier rocket, and has a payload capacity of {{convert|2850|kg}} to a {{convert|200|km|sing=on}} circular [[low Earth orbit]] with an [[inclination]] of 56.8° from Baikonur, and {{convert|2800|kg}} to a 200 kilometre orbit at 62.8° from Plesetsk.<ref name="Samara"/>

==Operational History==
In 2009, the maiden flight of the Soyuz-2-1v was announced as being scheduled for 2010, with this later being delayed to 2011 and then 2012 by development delays and payload availability. By June 2011 it was scheduled to occur at the end of 2012. During a test firing of a first stage prototype in August 2012, a test stand software malfunction resulted in damage to the stand and prototype, delaying the static testing programme.<ref>{{cite web|url=http://www.russianspaceweb.com/soyuz1_lv_development.html|title=Development of Soyuz-1|first=Anatoly|last=Zak|work=RussianSpaceWeb|accessdate=28 December 2013}}</ref>

The test was re-attempted in May 2013, and was declared successful despite the burn lasting 52 seconds shorter than had been expected. With this complete, the launch was scheduled for September 2013. It subsequently slipped to November and then December.<ref name="s101">{{cite web|url=http://www.spaceflight101.com/soyuz-2-1v.html|title=Soyuz 2-1v|publisher=Spaceflight 101|accessdate=28 December 2013}}</ref>

The maiden flight – which made use of a [[Volga (rocket stage)|Volga]] upper stage – carried the [[Aist 1]] microsatellite and a pair of [[SKRL-756]] calibration spheres. Ahead of the launch, the rocket was rolled out to [[Plesetsk Cosmodrome Site 43|Site 43/4]] at the [[Plesetsk Cosmodrome]] on 18 December 2013 with the launch scheduled for 23 December.<ref name="s101"/>

The launch was delayed beyond 23 December by problems found during late testing at the pad. An attempt to launch was made on 25 December, but it was scrubbed around ten minutes before the liftoff, which had been scheduled for 14:00 UTC. Despite reports that the launch could not take place before the end of the year, it was rescheduled for 10:30 UTC on 28 December.<ref>{{cite web|url=http://www.russianspaceweb.com/soyuz1_lv_aist.html|title=Soyuz-2-1v lifts off successfully|first=Anatoly|last=Zak|work=RussianSpaceWeb|accessdate=28 December 2013}}</ref> A further last-minute delay pushed the liftoff back to 12:30 UTC (16:30 local time), at which time the launch took place successfully.<ref>{{cite web|url=http://en.ria.ru/russia/20131228/186021089/After-Series-of-Delays-Russia-Launches-New-Soyuz-Rocket.html|title=After Series of Delays, Russia Launches New Soyuz Rocket|publisher=RIA Novosti|date=28 December 2013|accessdate=28 December 2013}}</ref> Spacecraft separation occurred 100 minutes later, at 14:10 UTC.<ref>{{cite web|url=http://www.nasaspaceflight.com/2013/12/russia-debut-soyuz-2-1v-plesetsk/|title= Russia conducts debut launch of Soyuz-2-1v|author=Nathaniel Downes and Chris Bergin|publisher=NASASpaceflight.com|accessdate=28 December 2013}}</ref>

The second launch of the vehicle on December 5, 2015 carried two payloads Kanopus-ST and KYuA-1, while the Kanopus-ST failed to separate from the final stage.<ref name="reuters">{{cite web|url=http://in.reuters.com/article/press-digest-russia-dec-idINL8N13W0U620151207|author=Reuters Editorial|title=PRESS DIGEST - RUSSIA - Dec 7|website=Reuters|accessdate=10 December 2017}}</ref><ref name="spaceflightinsider">{{cite web|url=http://www.spaceflightinsider.com/missions/defense/russia-successfully-launches-kanopus-st-satellite-into-orbit/|title=Russian Soyuz-2.1v launch a partial failure|website=SpaceFlight Insider|accessdate=10 December 2017}}</ref>

An unannounced launch carried a secret military payload on June 23, 2017.<ref>{{cite web |url=https://spaceflightnow.com/2017/06/23/secret-russian-satellite-launched-from-plesetsk-cosmodrome/ |title=Secret Russian satellite launched from Plesetsk Cosmodrome |last=Clark |first=Stephen |date=23 June 2017 |access-date=24 June 2017 }}</ref>

The next flight was on 29 March 2018.

== Photogallery from Paris Air Show 2011 ==
Russia exhibited a model of the Soyuz-2-1v during the [[2011 Paris Air Show]] at [[Le Bourget]].
<gallery>
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take1.JPG|General view of the rocket
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take3.jpg|Second stage view
Image:Soyuz 2.1 (Союз 2.1в) Paris Air Show 2011 take2.jpg|Detailed view of the payload section
</gallery>

==References==
{{reflist|30em}}

{{Expendable launch systems}}
{{Russian launch vehicles}}
{{R-7 rockets}}

{{Use British English|date=January 2014}}
{{Use dmy dates|date=January 2014}}

[[Category:R-7 (rocket family)]]
[[Category:Space launch vehicles of Russia]]
[[Category:2013 in spaceflight]]
[[Category:Vehicles introduced in 2013]]

[[ru:Союз-1 (ракета-носитель)]]

Tecnam P2012 Traveller

2017-12-26T05:01:50Z

Blastr42:

{{use dmy dates|date=April 2016}}
{|{{Infobox aircraft begin
|name = P2012 Traveller
|image = File:P2012_Traveller.jpg
|caption = 
|alt = 
}}{{Infobox aircraft type
|type = Twin-engined utility aircraft
|national origin= [[Italy]]
|manufacturer = [[Tecnam]]
|first flight = 21 July 2016
|introduced = planned for January 2019<ref name=AvWeek8oct2017/>
|retired = 
|status = 
|primary user = [[Cape Air]]
|more users = 
|produced = 2016-present
|number built =
|program cost = 
|unit cost = €2.2 million ($2.3 million)<ref name=FG170406/>
|developed from = 
|variants with their own articles = 
}}
|}

The '''Tecnam P2012 Traveller''' is a [[utility aircraft]] being developed by [[Costruzioni Aeronautiche Tecnam]], based in [[Capua]], Italy, near Naples.<ref>{{cite press release |title= Tecnam announces the launch of the P2012 Traveller |url= https://archive.is/yU9S |publisher= [[Tecnam]] |date= 13 April 2011 }}</ref>

== Development ==

In November 2015, three prototypes were under construction at Capua while [[Cape Air]], a [[Massachusetts]]-based [[commuter airline]], signed a letter of intent to order 100 aircraft to replace their existing [[Cessna 402]]s.<ref name=Flight4nov2015>{{cite news |work= Flightglobal |date= 4 November 2015 |title= Traveller takes shape as Tecnam sticks to timeline |url= https://www.flightglobal.com/news/articles/traveller-takes-shape-as-tecnam-sticks-to-timeline-418585/}}</ref>
Rollout of the first completed unit occurred on 1 April 2016.<ref>{{cite news |url= http://aviationweek.com/commercial-aviation/tecnam-rolls-out-twin-piston-short-haul-aircraft |title= Tecnam Rolls Out Twin Piston Short-Haul Aircraft |work= [[Aviation Week & Space Technology]] |date= 1 April 2016}}</ref>

It first flew on 21 July 2016.<ref>{{cite web |url= https://www.flightglobal.com/news/articles/tecnam-p2012-traveller-takes-flight-427793/ |title= Tecnam P2012 Traveller takes flight |work= Flight Global |date= 25 July 2016}}</ref>
In April 2017, the first prototype has flown more than 100 hours and the second test aircraft should join the certification campaign in September, with a certification target for December 2018. The company has said that between 25 and 35 P2012s should be delivered in 2019 and more in following years.<ref name=FG170406>{{cite news |url= https://www.flightglobal.com/news/articles/aero-tecnam-p2012-traveller-makes-its-international-435961/ |title= Tecnam P2012 Traveller makes its international debut |date= 6 April 2017 |work= flightglobal}}</ref>

Six customers from Argentina, the South Pacific region and Russia were added at the April 2017 [[AERO Friedrichshafen]], the second prototype was completed in late 2017.
The first 20 delivery schedule to Cape Air was firmed on 21 September 2017: first deliveries are due in January 2019 after EASA and FAA certification.<ref name=AvWeek8oct2017>{{cite news |url= http://aviationweek.com/nbaa-2017/emerging-aircraft-props-and-turboprops |title= Emerging Aircraft: Props And Turboprops |date= Oct 8, 2017 |author= Paul Jackson |work= Aviation Week Network }}</ref>

== Design ==

The Traveller is a high-wing, fixed landing-gear, twin [[piston engine]]d aircraft.<ref name=Flight4nov2015/>
It is designed to be compliant with both FAR part 23 and EASA CS-23 regulations and Cape Air is partnering with Tecnam on the design.<ref name=FG110413>{{cite news |url= https://www.flightglobal.com/news/articles/aero11-tecnam-unveils-three-new-aircraft-355536/ |title=AERO11: Tecnam unveils three new aircraft |publisher= [[Flightglobal]] |date= 13 April 2011}}</ref>
A new factory at Capua was purpose-built to produce the replacement for [[Piper PA-31]]s and [[Cessna 402]] series twins.<ref name=AvWeek8oct2017/>

==Specifications==
{{aircraft specifications
| plane or copter? = plane
| jet or prop? = prop
|ref =Tecnam<ref>{{cite web |title= Specifications |url= http://p2012.tecnam.org/technical-specs/specifications/ |publisher= Tecnam}}, {{cite web |url= http://p2012.tecnam.org/general-description/competitor-table/ |title= Competitor Table |publisher= Tecnam |date= 13 Apr 2017}}</ref>
|crew = 1/2 pilots
|capacity = 9 passengers
|payload main = {{#expr:3480-2350}} kg 
|payload alt = {{#expr:7672-5181}} lb
|length main = 11.8 m
|length alt = 38.6 ft
|span main = 14.0 m
|span alt = 45.93 ft
|height main = 4.4 m
|height alt = 14.4 ft
|area main = {{#expr:3600/142round1}} m² 
|area alt = {{#expr:7937/29round1}} ft²
|empty weight main = 2250 kg
|empty weight alt = 4960 lb
|max takeoff weight main = 3600 kg
|max takeoff weight alt = 7937 lb
|more general = '''Fuel capacity:''' 800 l (212 USgal)

| engine (prop) = [[Lycoming O-540|Lycoming TEO540]]C1A
| type of prop = [[horizontally-opposed]], turbocharged, six-cylinder, direct-drive air-cooled [[piston engine]]s
| number of props = 2
| power main = 375 hp
| propeller or rotor? = propeller
| propellers = [[MT-Propeller]]

|cruise speed main = 190 kts
|cruise speed alt = {{cvt|190|knot|km/h|disp=out|0}}
|cruise speed note = 10.000 ft max cruise
|stall speed main = 60 kts
|stall speed alt = {{cvt|60|knot|km/h|disp=out|0}}
|range main = 907 nm
|range alt = {{cvt|907|nmi|km|disp=out}}
|climb rate main = 1500 ft/min
|climb rate alt = {{cvt|1500|ft/min|m/s|disp=out|1}}
|climb rate more = ''Single engine:'' {{cvt|300|ft/min|m/s|1}}
|loading main = 142 kg/m²
|loading alt = 29 lb/ft²
|power/mass main = {{#expr:3600/(2*375)round1}} kg/hp
|fuel consumption = {{cvt|30|gal/h|l/h|0}} at {{cvt|150|knots|km/h|0}} [{{#expr:150/30round2}} nmi/gal; {{#expr:278/114round1}} km/l] to {{cvt|47.6|gal/h|l/h|0}} at {{cvt|180|knots|km/h|0}} [{{#expr:180/47.6round2}} nmi/gal; {{#expr:333/180round1}} km/l]<ref>{{cite web |url= http://p2012.tecnam.org/range/ |title= range |publisher= Tecnam}}</ref>
|more performance =
* '''Takeoff:''' {{cvt|600|m|ft|0}}
* '''Landing:''' {{cvt|500|m|ft|0}}
}}

==See also==
{{Aircontent|

|related=
* [[Tecnam P2006T]]
|similar aircraft =
* [[Cessna 208 Caravan]]
* [[Britten-Norman Islander]]
* [[Piper PA-31 Navajo]]
* [[Cessna 402]]
* [[Quest Kodiak]]

|lists=
|see also=
}}

==References==
{{Reflist}}

==External links==
{{commons category|Tecnam}}
* [http://p2012.tecnam.org/ Tecnam P2012 homepage]

{{Tecnam aircraft}}

[[Category:Tecnam aircraft]]
[[Category:Twin-engined tractor aircraft]]
[[Category:High-wing aircraft]]
[[Category:Aircraft first flown in 2016]]
[[Category:Italian civil utility aircraft 2010–2019]]

OmegA

2017-12-14T06:59:15Z

Blastr42: /* External links */

{{Infobox rocket
|name = Next Generation Launcher
|manufacturer = [[Orbital ATK]]
|country-origin = United States
|height = 59.84 m (196.33 ft)
|diameter = 3.71 m (12.17 ft) First Stage 5.25 m (17.2 ft) Upper Stage
|mass =
|stages = 3
|capacities =
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = 5,500-8,500 kg (12,125-18,739 lb) (500 Series)
}}
{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = 5,250-7,000 kg (11,574-15,432 lb) (500XL Series)
}}
|family = [[Shuttle-Derived Launch Vehicle]]
Preceded by [[Liberty (rocket)|Liberty]]
|status = Under Development
|sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]]
|launches = 0
|success = 0
|fail = 0
|partial = 0
|first= 2021 (projected)
|stagedata =
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name = [[Graphite-Epoxy Motor|GEM-63 or GEM-63XL]]
|number = 0 to 6
|diameter = {{convert|63|in|m|order=flip|abbr=on}}
|solid = yes
|total = 
|SI = {{convert|279.3|isp}}
|fuel = [[HTPB]]
}}
{{Infobox Rocket/Stage
|type = stage
|stageno = First
|engines = Castor 600 2-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]}}
{{Infobox Rocket/Stage
|type = stage
|stageno = Second
|engines = Castor 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]}}
{{Infobox rocket/Stage
|type = stage
|stageno = Third
|engines = 1 × [[BE-3|BE-3U]]
|thrust = 534 kN (120,000 lbf)
|SI = >400 seconds (vacuum)
|burntime = unknown
|fuel = [[LOX]]/[[LH2]]
}}
}}
'''Next Generation Launcher''' is a [[launch vehicle]] concept proposed by [[Orbital ATK]] as an [[Evolved Expendable Launch Vehicle|EELV]] replacement program intended for national security and commercial satellites.

Next Generation Launcher is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have combine a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Next Generational Launcher consists of Space Shuttle-derived solid stages with a cryogenic upper stage provide by [[Blue Origin]].<ref name=YahooFinance-20160524>{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spaceflightnow.com/2016/05/27/details-of-orbital-atks-proposed-heavy-launcher-revealed/|title=Details of Orbital ATK’s proposed heavy launcher revealed |publisher= Spaceflight Now|first=Stephen|last=Clark|date=27 May 2016}}</ref>

Next Generation Launcher is proposed as a vehicle to launch national security satellites for the United States Air Force, and could potentially launch other government and commercial payloads, including to [[Geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

==History==
[[File: Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, Orbital ATK was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract will fund the development of three technologies in support of the Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5-6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher is planned to take place between late 2017 and early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>

In April 2017, Orbital ATK revealed that NGL would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). NGL would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages. The basic configuration of four-segment [[solid rocket booster]] (SRB) with cryogenic upper stage, expands to baseline configuration of 2-segment first stage solid booster, with a 2-segment second stage solid booster, and third stage cryogenic booster. Also a heavy configuration adds a 4-segment first stage replacing the 2-segment booster of the baseline version. Additional versions are projected to add additional SRBs as side boosters. The SDLV SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs. Additional savings may be realized by homologating the SLS SRBs with NGL, replacing SLS' steel-cased SRBs with composite ones.<ref name=FloridaToday-2017-04-06> {{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }} </ref>

==References==
{{Reflist|2}}

==External links==
*[https://www.orbitalatk.com/flight-systems/space-launch-vehicles/NGL/default.aspx NGL official web site]

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a Saturn V-derived J2-X based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and Ares-derived J2-X based second stage

{{S-start}}
{{Succession box
| title = Single-stick SRB-based SDLV
| years = 2016-
| before = [[Liberty (rocket)|Liberty]]
| after = N/A CURRENT
}}
{{S-end}}

{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

OmegA

2017-12-14T06:58:43Z

Blastr42: /* External links */Added official web site

{{Infobox rocket
|name = Next Generation Launcher
|manufacturer = [[Orbital ATK]]
|country-origin = United States
|height = 59.84 m (196.33 ft)
|diameter = 3.71 m (12.17 ft) First Stage 5.25 m (17.2 ft) Upper Stage
|mass =
|stages = 3
|capacities =
{{Infobox rocket/payload
|location = [[Geostationary transfer orbit|GTO]]
|kilos = 5,500-8,500 kg (12,125-18,739 lb) (500 Series)
}}
{{Infobox rocket/payload
|location = [[Geostationary orbit|GEO]]
|kilos = 5,250-7,000 kg (11,574-15,432 lb) (500XL Series)
}}
|family = [[Shuttle-Derived Launch Vehicle]]
Preceded by [[Liberty (rocket)|Liberty]]
|status = Under Development
|sites = [[Kennedy Space Center|Kennedy]] [[LC-39B]] and [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]]
|launches = 0
|success = 0
|fail = 0
|partial = 0
|first= 2021 (projected)
|stagedata =
{{Infobox rocket/stage
|type = booster
|diff = 
|stageno = 
|name = [[Graphite-Epoxy Motor|GEM-63 or GEM-63XL]]
|number = 0 to 6
|diameter = {{convert|63|in|m|order=flip|abbr=on}}
|solid = yes
|total = 
|SI = {{convert|279.3|isp}}
|fuel = [[HTPB]]
}}
{{Infobox Rocket/Stage
|type = stage
|stageno = First
|engines = Castor 600 2-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]}}
{{Infobox Rocket/Stage
|type = stage
|stageno = Second
|engines = Castor 300 1-segment [[Space Shuttle Solid Rocket Booster|Shuttle-derived Solid Rocket Booster]]
|thrust =
|burntime =
|fuel = [[solid rocket|Solid]]}}
{{Infobox rocket/Stage
|type = stage
|stageno = Third
|engines = 1 × [[BE-3|BE-3U]]
|thrust = 534 kN (120,000 lbf)
|SI = >400 seconds (vacuum)
|burntime = unknown
|fuel = [[LOX]]/[[LH2]]
}}
}}
'''Next Generation Launcher''' is a [[launch vehicle]] concept proposed by [[Orbital ATK]] as an [[Evolved Expendable Launch Vehicle|EELV]] replacement program intended for national security and commercial satellites.

Next Generation Launcher is similar to the defunct [[Ares I]] and [[Liberty (rocket)|Liberty]] projects, both of which consisted of a five segment [[Space Shuttle Solid Rocket Booster]] (SRB) and a cryogenic second stage. Ares I would have combined a five-segment SRB with a [[J-2X]] powered second stage, while Liberty would have combine a five-segment SRB with the core stage of the European [[Ariane 5]] as a [[second stage]]. By comparison, Next Generational Launcher consists of Space Shuttle-derived solid stages with a cryogenic upper stage provide by [[Blue Origin]].<ref name=YahooFinance-20160524>{{cite web|url=https://finance.yahoo.com/news/orbital-planning-rocket-compete-u-210846496.html|title=Orbital planning new rocket to compete for U.S. military launches|publisher=Yahoo Finance|author=Irene Klotz|work=Reuters|date=24 May 2016}}</ref> It is intended to be launched from [[Kennedy Space Center]] [[LC-39B]] or [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 2|SLC-2]].<ref name="SpaceflightNow-20160527">{{cite web|url=https://spaceflightnow.com/2016/05/27/details-of-orbital-atks-proposed-heavy-launcher-revealed/|title=Details of Orbital ATK’s proposed heavy launcher revealed |publisher= Spaceflight Now|first=Stephen|last=Clark|date=27 May 2016}}</ref>

Next Generation Launcher is proposed as a vehicle to launch national security satellites for the United States Air Force, and could potentially launch other government and commercial payloads, including to [[Geostationary transfer orbit]]. Crewed spacecraft could also be launched, just as the predecessor Ares I and Liberty rockets, which were designed to launch the [[Orion (spacecraft)|Orion]] space capsule.<ref name=TheSpaceShow-20161031>{{cite episode|url=http://thespaceshow.com/show/31-oct-2016/broadcast-2804-jim-armor|id=Broadcast 2804 Jim Armor|title=General James B. Armor|number=2804|airdate=31 October 2016|series=The Space Show}}</ref>

==History==
[[File: Orbital ATK logo.svg|thumbnail|The Orbital ATK's Logo]]
In January 2016, Orbital ATK was one of two companies awarded funds by the United States Air Force to develop technologies to eliminate dependency on the Russian-made [[RD-180]] rocket engine.<ref name=SpaceNews-20160113>{{cite web|url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/|title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |publisher= SpaceNews.com |date=13 January 2016|author=Mike Gruss}}</ref> The award was worth an initial $46.9 million, with an option for up to $180.2 million total. This is to be matched by $31.1 million initially, and up to $124.8 million in company funds if all options of the contract are exercised. The contract will fund the development of three technologies in support of the Next Generation Launcher: the [[Graphite-Epoxy Motor|GEM-63XL]] strap-on booster, the Shuttle-derived [[Modular rocket|Common Booster Core]] and an extendable nozzle for the [[BE-3]]U upper stage engine. A previous effort, funded by NASA, demonstrated the technology for a composite motor case for Shuttle-derived boosters to replace the metal motor cases used during the Space Shuttle program.<ref name=SpaceFlightInsider-20131207>{{cite web|url=http://www.spaceflightinsider.com/organizations/nasa/one-on-one-with-atks-charlie-precourt-about-composite-materials-and-nasas-space-launch-system/|title=One-on-One with ATK's Charlie Precourt about composite materials and NASA's Space Launch System |publisher= SpaceFlight Insider|author=Jason Rhian|date=7 December 2013}}</ref>

In May 2016, Orbital ATK revealed their plans for the Next Generation Launcher, including the configuration and the intended business case.<ref name="SpaceflightNow-20160527"/> In addition to relying on Shuttle-derived boosters, the Next Generation Launcher intends to make use of existing launch infrastructure at [[Kennedy Space Center]] (KSC), including the [[Vehicle Assembly Building]] used by the Space Shuttle, with the possibility of polar orbit launches occurring from [[Vandenberg Air Force Base]]. NASA began looking for commercial users to operate unused space within the Vehicle Assembly Building in June 2015, and by April 2016, it was announced that Orbital ATK was in negotiations to lease High Bay 2.<ref name=SpaceFlightNow-20160421>{{cite web|url=https://spaceflightnow.com/2016/04/21/orbital-atk-eyes-kennedy-space-center-as-home-of-potential-new-launcher/|title=Orbital ATK eyes Kennedy Space Center as home of potential new launcher|publisher=Spaceflight Now|date=21 April 2016 |author=Stephen Clark}}</ref> Orbital ATK claimed that a minimum of 5-6 launches per year would be required to make the rocket profitable. Full development and introduction will be dependent on both demand and funding from the US Air Force. A final "go/no-go decision" to proceed with full development and introduction of the Next Generation Launcher is planned to take place between late 2017 and early 2018.<ref name=SpaceNews-20170310>{{cite web|url=http://spacenews.com/orbital-atk-expects-decision-on-new-rocket-by-early-2018/|title=Orbital ATK expects decision on new rocket by early 2018|publisher=SpaceNews|author=Jeff Foust |date= 10 March 2017}}</ref>

In April 2017, Orbital ATK revealed that NGL would be launched from pad 39B at KSC, sharing launch facilities and mobile transporter with the NASA [[Space Launch System]] (SLS). NGL would compete for USAF national security launches and NASA missions. There would be multiple configurations of the launch system, with multiple stages. The basic configuration of four-segment [[solid rocket booster]] (SRB) with cryogenic upper stage, expands to baseline configuration of 2-segment first stage solid booster, with a 2-segment second stage solid booster, and third stage cryogenic booster. Also a heavy configuration adds a 4-segment first stage replacing the 2-segment booster of the baseline version. Additional versions are projected to add additional SRBs as side boosters. The SDLV SRBs are to share avionics suites with other Orbital ATK rockets to reduce costs. Additional savings may be realized by homologating the SLS SRBs with NGL, replacing SLS' steel-cased SRBs with composite ones.<ref name=FloridaToday-2017-04-06> {{cite news |url= http://www.floridatoday.com/story/tech/science/space/2017/04/06/orbital-atk-optimistic-proposed-ksc-rocket/100091308/ |title= Orbital ATK optimistic about proposed KSC rocket |author= James Dean |publisher= Florida Today |date= 6 April 2017 }} </ref>

==References==
{{Reflist|2}}

==External links==
*[http://www.libertyspace.us/ Liberty official web site]

*[https://www.orbitalatk.com/flight-systems/space-launch-vehicles/NGL/default.aspx NGL official web site]

==See also==
*[[Ares I]], a proposed Constellation program rocket based on an SDLV SRB-derived first stage and a Saturn V-derived J2-X based second stage
*[[Liberty (rocket)]], a proposed rocket based on an SDLV SRB-derived first stage and Ares-derived J2-X based second stage

{{S-start}}
{{Succession box
| title = Single-stick SRB-based SDLV
| years = 2016-
| before = [[Liberty (rocket)|Liberty]]
| after = N/A CURRENT
}}
{{S-end}}

{{Orbital launch systems}}

[[Category:Partially reusable space launch vehicles]]
[[Category:Ares (rocket family)]]
[[Category:Shuttle-derived space launch vehicles]]

Minotaur V

2017-12-10T08:04:37Z

Blastr42: Typo on Diameter.

{{infobox rocket
|name = Minotaur V
|image_size = 250
|image = Minotaur V carrying LADEE at MARS Pad 0B 2013-09-04.jpg
|caption = The first Minotaur V at MARS before the launch of [[LADEE]].
|function = Expendable launch system
|manufacturer = [[Orbital ATK]]
|country-origin = United States
|height = 24.56 m<ref name=LADEEpresskit>{{cite web |title=Lunar Atmosphere and Dust Environment Explorer (LADEE) Launch |url=https://www.nasa.gov/sites/default/files/files/LADEE-Press-Kit-08292013.pdf |publisher=[[NASA]] |accessdate=8 September 2013}}</ref>
|diameter = 2.34 m<ref name=LADEEpresskit/>
|mass = 89,373 kg<ref name=LADEEpresskit/>
|stages = Five
|status = Active
|sites = [[Vandenberg AFB Space Launch Complex 8|SLC-8]], [[Vandenberg AFB]] [[Mid-Atlantic Regional Spaceport|LP-0B]], [[Mid-Atlantic Regional Spaceport|MARS]] [[Kodiak Launch Complex Pad 1|LP-1]], [[Kodiak Launch Complex|Kodiak]]
|first = 7 September 2013
|launches = 1
|success = 1
|capacities =
{{Infobox Rocket/Payload
|location = [[Geosynchronous transfer orbit|GTO]]
|kilos = 532 kg
}}
{{Infobox Rocket/Payload
|location = [[Trans Lunar Injection|TLI]]
|kilos = 342 kg
}}
|family = [[Minotaur (rocket)|Minotaur]]
|stagedata =
{{Infobox Rocket/Stage
|type = stage
|stageno = First
|name = [[LGM-118 Peacekeeper|SR-118]]
|engines = 1 [[solid rocket|Solid]]
|thrust = {{convert|1607|kN}}
|burntime = 83 seconds
|fuel = [[Solid rocket|Solid]]
}}
{{Infobox Rocket/Stage
|type = stage
|stageno = Second
|name = [[LGM-118 Peacekeeper|SR-119]]
|engines = 1 [[solid rocket|Solid]]
|thrust = {{convert|1365|kN}}
|burntime = 54 seconds
|fuel = [[Solid rocket|Solid]]
}}
{{Infobox Rocket/Stage
|type = stage
|stageno = Third
|name = [[LGM-118 Peacekeeper|SR-120]]
|engines = 1 [[solid rocket|Solid]]
|thrust = {{convert|329|kN}}
|burntime = 62 seconds
|fuel = [[Solid rocket|Solid]]
}}
{{Infobox Rocket/Stage
|type = stage
|stageno = Fourth
|name = [[Star-48]]BV
|engines = 1 [[solid rocket|Solid]]
|thrust = {{convert|64|kN}}
|burntime = 84 seconds
|fuel = [[Solid rocket|Solid]]
}}
{{Infobox Rocket/Stage
|type = stage
|stageno = Fifth
|diff = Baseline
|name = [[Star-37]]FM
|engines = 1 [[solid rocket|Solid]]
|thrust = {{convert|47.26|kN}}
|burntime = 63 seconds
|fuel = [[Solid rocket|Solid]]
}}
{{Infobox Rocket/Stage
|type = stage
|stageno = Fifth
|diff = Optional
|name = [[Star-37]]FMV
|engines = 1 [[solid rocket|Solid]]
|thrust =
|burntime =
|fuel = [[Solid rocket|Solid]]
}}
}}

The '''Minotaur V''' is an American [[expendable launch system]] derived from the [[Minotaur IV]], itself a derivative of the [[LGM-118 Peacekeeper]] [[Intercontinental ballistic missile|ICBM]]. It was developed by [[Orbital Sciences Corporation]], and made its maiden flight on 7 September 2013 carrying the [[Lunar Atmosphere and Dust Environment Explorer]] spacecraft for [[NASA]].<ref>{{cite web |url=http://www.nasa.gov/mission_pages/LADEE/main/ |title=Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission website |publisher=[[NASA]]}}</ref>

==Design==
The Minotaur V is a five-stage vehicle, and is designed to place up to {{convert|630|kg}} of payload into a [[geosynchronous transfer orbit]], or {{convert|342|kg}} on a [[trans-lunar injection|trans-lunar]] trajectory.<ref name=MTVFactsheet>{{cite web |url=http://www.orbital.com/NewsInfo/Publications/Minotaur_V_Fact.pdf |title=Fact Sheet |work=Minotaur V |publisher=[[Orbital Sciences Corporation]] |accessdate=22 January 2013}}</ref> It consists of a Minotaur IV+, with a [[Star-37]] as a fifth stage. Two variants are available, one with a [[spin stabilization|spin-stabilized]] Star-37FM upper stage, and the other with a Star-37FMV capable of [[3-axis stabilized spacecraft|three-axis stabilization]].<ref name=MTVFactsheet/> The Star-37FMV upper stage is heavier, reducing payload capacity, but is more maneuverable.

==Launch pads==
[[Vandenberg AFB Space Launch Complex 8|Space Launch Complex 8]] at the [[Vandenberg Air Force Base]], [[Mid-Atlantic Regional Spaceport Launch Pad 0|Pad 0B]] at the [[Mid-Atlantic Regional Spaceport]] (MARS), and [[Kodiak Launch Complex Pad 1|Pad 1]] of the [[Kodiak Launch Complex]] are all capable of accommodating the Minotaur V. {{as of|2013}}, all scheduled launches are from MARS.<ref>{{cite web |url=http://space.skyrocket.de/doc_lau/minotaur-4.htm |title=Minotaur-3/-4/-5 (OSP-2 Peacekeeper SLV) |first=Gunter |last=Krebs |publisher=Gunter's Space Page |accessdate=22 January 2013}}</ref>

==Launch history==
The initial launch of a Minotaur V occurred on 7 September 2013 at 03:27 UTC from [[Mid-Atlantic Regional Spaceport Launch Pad 0|Launch Pad 0B]] at the [[Mid-Atlantic Regional Spaceport]] in Virginia. The payload for the maiden flight was the [[LADEE]] [[Moon|lunar]] exoatmosphere science spacecraft.<ref name=sfn-20130907>{{cite news |url=http://www.spaceflightnow.com/minotaur/ladee/130907launch/#.Uisgjn_b0_s |title=Moon mission hits snag after flawless late-night launch |author=Stephen Clark |publisher=Spaceflight Now |date=7 September 2013 |accessdate=7 September 2013}}</ref>
While now separated from the LADEE spacecraft, both the fourth and fifth stages of the Minotaur V reached orbit, and are now [[:Category:Derelict satellites orbiting Earth|derelict satellites]] in [[Earth orbit]].<ref name=nsf20130906>
{{cite web |last=Graham |first=William |title=Orbital’s Minotaur V launches LADEE mission to the Moon |url=http://www.nasaspaceflight.com/2013/09/orbitals-minotaur-v-launch-ladee-mission-moon/ |accessdate=8 September 2013 |publisher=[[NASAspaceflight.com]] |date=6 September 2013}}</ref>

==References==
{{Reflist|colwidth=25em}}

{{Expendable launch systems}}
{{US launch systems}}

[[Category:Minotaur (rocket family)]]

Talk:Soyuz-2-1v

2017-12-10T01:33:16Z

Blastr42: /* Combine articles? */ new section

{{WikiProjectBannerShell|1=
{{WikiProject Spaceflight|class=start|importance=}}
{{WikiProject Rocketry|class=start}}
{{WikiProject Russia|class=start}}
}}

== Name: Soyuz-2.1v? ==

Shouldn't the article be named "Soyuz-2.1v" instead of "Soyuz-2-1v"? That's the spelling I'm seeing on all the Russian references. --[[User:IanOsgood|IanOsgood]] ([[User talk:IanOsgood|talk]]) 14:44, 28 December 2013 (UTC)
:The two designations are used interchangeably for the other Soyuz-2 configurations. [http://www.samspace.ru/products/launch_vehicles/rn_soyuz_2_1v/ The manufacturer] uses a hyphen so I'd tend to go with that. --'''''[[User:WDGraham|W.]] [[User talk:WDGraham|D.]] [[Special:Contributions/WDGraham|Graham]]''''' 15:49, 28 December 2013 (UTC)

== 2nd Flight ==

Will there be a second flight? — Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/93.229.245.179|93.229.245.179]] ([[User talk:93.229.245.179|talk]]) 08:17, 2 December 2015 (UTC) 

== Combine articles? ==

Should this article be combined with the rest of the Soyuz 2.1a/b/ST article? It’s still in that family, sharing launch facilities, tooling and design features. Is there a compelling reason to keep it separate? [[User:Blastr42|Blastr42]] ([[User talk:Blastr42|talk]]) 01:33, 10 December 2017 (UTC)

Vega (rocket)

2017-11-28T20:37:21Z

Blastr42: /* Future developments */

{{Use dmy dates|date=January 2015}}
{{Infobox rocket
|image = File:Sentinel-2_and_vega.jpg
|image_size = 250px
|caption = Vega VV09 liftoff with [[Sentinel-2B]]
|name = Vega
|function = [[Small-lift launch vehicle]]
|manufacturer = [[Avio]]
|country-origin = [[Italy]], [[European Union]]
|cpl = {{US$|37 million[http://www.gao.gov/products/GAO-17-609]}}
|height = {{convert|30|m|ft|abbr=on}}
|diameter = {{convert|3|m|ft|abbr=on}}
|mass = {{convert|137000|kg|lb|abbr=on}}
|stages = 4
|capacities =
{{Infobox rocket/payload
|location = [[Polar orbit]] (700km / [[Orbital inclination|inclination]] 90°)
|kilos = {{convert|1430|kg|lb|abbr=on}}
}}
{{Infobox rocket/payload
|location = [[Elliptic orbit]] (1500x200km / [[Orbital inclination|inclination]] 5.4°)
|kilos = {{convert|1963|kg|lb|abbr=on}}
}}
{{Infobox rocket/payload
|location = [[Sun-synchronous orbit|SSO]] (400km)
|kilos = {{convert|1450|kg|lb|abbr=on}}
}}
|comparable = {{flatlist |
* [[Delta II]] 7420
* [[Minotaur IV]]
* [[Minotaur-C]]
* [[Rokot]]
* [[Soyuz-2-1v]]
}}
|status = Active
|sites = [[Guiana Space Centre]] [[ELA-1|SLV]]
|launches = 11
|success = 11
|fail =
|partial =
|other_outcome =
|first = {{Start date|2012|02|13|df=y}}<ref>{{cite web |url=http://www.esa.int/Our_Activities/Launchers/Launch_vehicles/Vega3/Vega_liftoff |title=Vega liftoff |publisher=ESA}}</ref>
|last = {{Start date|2017|11|7|df=y}}
|payloads =

|stagedata =
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = First
|name = [[P80 (rocket stage)|P80]]<ref name="AvioVegaLeaflet">{{cite web|url=http://www.avio.com/files/catalog/pdf/motore_p80_75.pdf|title=Vega Satellite Launcher|author=[[Avio]]|format=PDF|accessdate=24 July 2014|deadurl=yes|archiveurl=https://web.archive.org/web/20150923180829/http://www.avio.com/files/catalog/pdf/motore_p80_75.pdf|archivedate=23 September 2015|df=dmy-all}}</ref><ref name="AvioSite">{{cite web|url=http://www.avio.com/en/catalog/space/propulsione_spaziale/products|title=Avio Space|author=[[Avio]]|format=PDF|accessdate=24 July 2014|deadurl=yes|archiveurl=https://web.archive.org/web/20140726232946/http://www.avio.com/en/catalog/space/propulsione_spaziale/products|archivedate=26 July 2014|df=dmy-all}}</ref><ref name="ESAVegaSpecial" />
|length = {{convert|11.7|m|ft|abbr=on}}
|diameter = {{convert|3|m|ft|abbr=on}}
|width =
|empty = {{convert|7330|kg|lb|abbr=on}}
|gross = {{convert|95695|kg|lb|abbr=on}}
|engines = off
|thrust = {{convert|2261|kN|abbr=on|sigfig=4|lk=on}}
|total =
|SI = {{convert|280|isp|abbr=on}}
|burntime = 110 s
|fuel = [[Hydroxyl-terminated polybutadiene|HTPB]] ([[solid rocket|Solid]])
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Second
|name = [[Zefiro 23]]
|length = {{convert|8.39|m|ft|abbr=on}}
|diameter = {{convert|1.9|m|ft|abbr=on}}
|width =
|empty = {{convert|2850|kg|lb|abbr=on}}
|gross = {{convert|28850|kg|lb|abbr=on}}
|engines = off
|thrust = {{convert|871|kN|abbr=on|sigfig=4|lk=on}}
|total =
|SI = {{convert|287.5|isp|abbr=on}}
|burntime = 77 s
|fuel = [[Hydroxyl-terminated polybutadiene|HTPB]] ([[solid rocket|Solid]]) <ref>http://www.astronautix.com/engines/zefiro23.htm</ref>
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Third
|name = [[Zefiro 9]]
|length = {{convert|4.12|m|ft|abbr=on}}
|diameter = {{convert|1.9|m|ft|abbr=on}}
|width =
|empty = {{convert|1315|kg|lb|abbr=on}}
|gross = {{convert|11815|kg|lb|abbr=on}}
|engines = off
|thrust = {{convert|260|kN|abbr=on|sigfig=4|lk=on}}
|total =
|SI = {{convert|296|isp|abbr=on}}
|burntime = 120 s
|fuel = [[Hydroxyl-terminated polybutadiene|HTPB]] ([[solid rocket|Solid]]) <ref>http://www.astronautix.com/engines/zefiro9.htm</ref>
}}
{{Infobox rocket/stage
|type = stage
|diff =
|stageno = Upper
|name = AVUM
|length = {{convert|1.7|m|ft|abbr=on}}
|diameter = {{convert|1.9|m|ft|abbr=on}}
|width =
|empty = {{convert|147|kg|lb|abbr=on}}
|gross = {{convert|697|kg|lb|abbr=on}}
|engines = 1 [[RD-843]]
|thrust = {{convert|2.42|kN|abbr=on|sigfig=4|lk=on}}
|total =
|SI = {{convert|315.5|isp|abbr=on}}
|burntime = 667 s
|fuel = [[UDMH]]/[[N2O4]]
}}
}}

'''Vega''' ({{lang-it|Vettore Europeo di Generazione Avanzata}},<ref>ESA: Antonio Fabrizi: from "nuts and bolts" to Europe’s launchers of today and tomorrow [http://www.esa.int/SPECIALS/Space_Year_2007/SEMFRSQ08ZE_0.html]</ref> ''Advanced Generation European Carrier [[Rocket]]''),<ref>ESA: Antonio Fabrizi: from "nuts and bolts" to Europe’s launchers of today and tomorrow [http://www.esa.int/SPECIALS/Space_Year_2007/SEMFRSQ08ZE_0.html]</ref> is an [[expendable launch system]] in use by [[Arianespace]] jointly developed by the [[Italian Space Agency]] and the [[European Space Agency]]. Development began in 1998 and the first launch took place from the [[Guiana Space Centre]] on February 13, 2012.<ref name="ESAVegaSpecial">{{cite web|url=http://www.esa.int/SPECIALS/Vega/index.html |title=ESA – Vega |publisher=Esa.int |date=3 February 2012 |accessdate=14 February 2012}}</ref> Arianespace has ordered launchers covering the period till at least the end of 2018.<ref name="AS20131120"/>

It is designed to launch small payloads — 300 to 2,500 kg [[satellite]]s for scientific and [[Earth observation satellite|Earth observation]] missions to [[polar orbit|polar]] and [[Low Earth orbit|low Earth]] orbits.<ref>{{cite news | url=http://www.bbc.co.uk/news/science-environment-16956324 | title=Vega launcher makes first flight | first=Jonathan | last=Amos | date=13 February 2012 | accessdate=13 February 2012 | publisher=BBC News}}</ref> The reference Vega mission is a polar orbit bringing a spacecraft of 1,500 kilograms to an altitude of 700 kilometers.

The rocket, named after [[Vega]], the brightest star in the constellation [[Lyra]],<ref>{{cite web
| url = http://www.space.com/14548-europe-launches-vega-rocket-maiden-voyage.html
| title = Europe Launches New Vega Rocket on Maiden Voyage
| author = Tariq Malik
| publisher = [[Space.com]]
| quote = The Italian-built Vega rocket is named after the second-brightest star in the northern hemisphere
| date = 13 February 2012
| accessdate = 29 May 2014}}</ref> is a single-body launcher (no strap-on boosters) with three [[solid rocket]] stages: the [[P80 (rocket stage)|P80]] first stage, the Zefiro 23 second stage, and the Zefiro 9 third stage. The upper module is a [[liquid rocket]] called AVUM. The improved version of the P80 stage, the P120C, will be used as side booster of the [[Ariane 6]]. Italy is the leading contributor to the Vega program (65%), followed by France (13%).<ref>{{cite news|url=http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/awst/2012/02/06/AW_02_06_2012_p50-420459.xml&headline=Vega%20Launcher%20Targets%20Government%20Market |title=Vega Launcher Targets Government Market |publisher=Aviation Week |date=6 February 2012 |accessdate=14 February 2012}}</ref> Other participants include Spain, Belgium, the Netherlands, Switzerland and Sweden.<ref name="spaceflightnow">{{cite web | url=http://www.spaceflightnow.com/news/n1202/14germanyvega/ | title=Vega launcher program courts German participation | publisher=Spaceflight Now | date=14 February 2012 | accessdate=14 February 2012 | author=CLARK, S. | pages=1}}</ref>

==Development==
===Background===
During the mid-1990s, French firms [[Aérospatiale]] and SEP, along with Italian firm [[Bombrini-Parodi-Delfino]] (BPD), commenced discussions on the development of a proposed Ariane Complementary Launcher (ACL). Around the same time, Italy began to champion the concept of a new solid-propellant satellite launcher.<ref name = "flight 1996"/> This proposed launcher, dubbed ''Vega'', was promoted as functioning to expand the range of European launch capabilities; Vega would be capable of launching a 1,000kg payload capability into a 700km polar orbit. From the onset, the first of three stages would be based on the solid booster of the existing [[Ariane 5]] expendable launch system while the second and third stages would be make use of the in-development Zefiro rocket motor.<ref>Moxon, Julian. [https://www.flightglobal.com/news/articles/esa-plan-emphasises-launchers-35235/ "ESA plan emphasises launchers."] ''Flight International'', 8 April 1998.</ref><ref name = "late 1998"/>

However, it was recognised to be a costly project and thus difficult for Italy alone to finance; accordingly, international partners were sought early on in order to proceed with development.<ref name = "flight 1996">[https://www.flightglobal.com/news/articles/launcher-proposals-10282/ "Launcher proposals."] ''Flight International'', 18 December 1996.</ref> In April 1998, it was publicly stated that the Vega programme was dependent upon the securing of roughly ECU70 million ($77 million) of industrial investment, as well as the availability of around ECU350 million of funding that had been requested from interested member states of the [[European Space Agency]] (ESA), led by France and Italy.<ref>[https://www.flightglobal.com/news/articles/italy-leads-esa-interest-in-vega-k-development-36542/ "Italy leads ESA interest in Vega K development."] ''Flight International'', 29 April 1998.</ref> During June 1998, it was announced that ministers from the ESA member states had agreed to proceed with the first phase of the development programme for Vega; the participating members were France, Belgium, the Netherlands, Spain and Italy - the latter had assumed 55 per cent of the burden for financing the programme.<ref>[https://www.flightglobal.com/news/articles/esa-to-develop-small-satellite-launcher-38879/ "ESA to develop small satellite launcher."] ''Flight International'', 1 July 1998.</ref><ref name = "late 1998">Furniss, Tim. [https://www.flightglobal.com/news/articles/a-late-entry-39350/ "A late entry."] ''Flight International'', 15 July 1998.</ref>

By September 1998, it was projected that, if fully funded, Vega would perform its first launch during 2002.<ref>Furniss, Tim. [https://www.flightglobal.com/news/articles/new-european-launcher-awaits-full-funding-41980/ "New European launcher awaits full funding."] ''Flight International'', 8 September 1998.</ref> However, by early 1998, France was publicly showing displeasure in the programme, leading to disputes in its funding.<ref>[https://www.flightglobal.com/news/articles/second-test-for-vegas-zefiro-53678/ "Second test for Vega's Zefiro."] ''Flight International'', 7 July 1999.</ref><ref>Furniss, Tim. [https://www.flightglobal.com/news/articles/finding-a-role-54316/ "Finding a Role."] ''Flight International'', 28 July 1999.</ref> A new, higher- performance version of the Vega was proposed, but this failed to sufficiently satisfy France. In September 1999, France decided to withdraw from the Vega programme entirely, leading to fears for the future of the launcher.<ref>[https://www.flightglobal.com/news/articles/esa-ponders-vegas-future-after-france-withdraws-56125/ "ESA ponders Vega's future after France withdraws."] ''Flight International'', 15 September 1999.</ref> In November 1999, the ESA formally dropped Vega as an endorsed programme, a decision which was largely attributed to France's withdrawal; Italy declared that it would proceed regardless, and threatened to re-direct its allocated contributions for the further development of the Ariane 5 to meet the shortfall.<ref>Moxon, Julian and Andy Nativi. [https://www.flightglobal.com/news/articles/french-withdrawal-prompts-esa-to-drop-vega-project-57876/ "French withdrawal prompts ESA to drop Vega project."] ''Flight International'', 3 November 1999.</ref><ref>[https://www.flightglobal.com/news/articles/esa-budgets-for-ariane-5-updates-61417/ "ESA budgets for Ariane 5 updates."] ''Flight International'', 1 February 2000.</ref>

Around 2000, an alternative use for the Vega was explored as a medium-class booster rocket to be used in conjunction with an improved, up-rated model of the Ariane 5 heavy launcher.<ref>Furniss, Tim. [https://www.flightglobal.com/news/articles/arianespace-adds-eurokot-to-satellite-launcher-range-66445/ "Arianespace adds Eurokot to satellite launcher range."] ''Flight International'', 6 June 2000.</ref> In October 2000, it was announced that France and Italy had settled their year-long dispute over the Vega programme; France and Italy agreed to provide 35 per cent and 52 per cent, respectively, of the financing towards the all-composite P80 booster for the Ariane 5 — work which would be included in the Vega programme.<ref>Moxon, Julian and Giorgio di Barnado. [https://www.flightglobal.com/news/articles/vega-agreement-paves-way-for-p80-booster-for-ariane-122070/ "Vega agreement paves way for P80 booster for Ariane 5."] ''Flight International'', 31 October 2000.</ref> In March 2001, [[FiatAvio]] and the Italian Space Agency formed a new company, European Launch Vehicle (ELV), to assume responsibility for the majority of development work on the Vega programme.<ref>Nativi, Andy. [https://www.flightglobal.com/news/articles/italians-form-launcher-company-126988/ "Italians form launcher company."] ''Flight International'', 6 March 2001.</ref> By 2003, there was concerns that the ESA's recent adoption of the Russian [[Soyuz at the Guiana Space Centre|Soyuz]] launcher would directly compete with the in-development Vega; demands for such launchers had declined with a downturn in the mobile telecommunications satellite market and doubts over the European [[Galileo (satellite navigation)|Galileo]] [[satellite navigation]] system.<ref>Furniss, Tim. [https://www.flightglobal.com/news/articles/face-the-facts-with-jean-yves-le-gall-166890/ "Face the facts with... Jean-Yves Le Gall."] ''Flight International'', 15 June 2003.</ref>

===Programme launch===
In March 2003, contracts for development of the Vega launcher were signed by the ESA and [[CNES|Centre national d'études spatiales]] (CNES), the French space agency; Italy provided 65 per cent of funding while six additional nations contributed the remainder.<ref>Furniss, Tim. [https://www.flightglobal.com/news/articles/europe-starts-vega-development-162369/ "Europe starts Vega development."] ''Flight International'', 4 March 2003.</ref> In May 2004, it was reported that a contract was signed between commercial operator [[Arianespace]] and prime contractor ELV to perform vehicle integration at [[Kourou]], [[French Guiana]].<ref>[https://www.flightglobal.com/news/articles/vega-nears-maiden-flight-182063/ "Vega nears maiden flight."] ''Flight International'', 25 May 2004.</ref> In November 2004, construction commenced upon a new dedicated launch pad for the Vega launcher at Kourou, this included a [[bunker]] and a self-propelled structure to assist assembly of the stages; this site was built over the original launch pad for the retired [[Ariane 1]] launcher.<ref>[https://www.flightglobal.com/news/articles/vega-launch-pad-taking-shape-190559/ "Vega launch pad taking shape."] ''Flight International'', 23 November 2004.</ref><ref>Coppinger, Rob. [https://www.flightglobal.com/news/articles/bigger-stage-202663/ "Bigger Stage."] ''Flight International'', 8 November 2005.</ref> In September 2005, the successful completion of key tests on the Vega's solid rocket motor igniters, a key milestone, was reported.<ref>Bentley, Ross. [https://www.flightglobal.com/news/articles/key-tests-for-vega-igniters-201673/ "Key tests for Vega igniters."] ''Flight International'', 21 September 2005.</ref>

In November 2005, the ESA declared its desire for the development and deployment of an [[Electrically powered spacecraft propulsion|electric propulsion-powered]] module to work in conjunction with the Vega launcher; this envisioned module would transfer payloads between [[low Earth orbit]] (LEO) and a [[geostationary orbit]].<ref>[https://www.flightglobal.com/news/articles/esa-wants-electronic-module-for-vega-vehicle-203099/ "ESA wants electronic module for Vega vehicle."] ''Flight International'', 22 November 2005.</ref> During November 2005, it was reported that both [[Israel]] and [[India]] had shown formal interest in the Vega programme.<ref>[https://www.flightglobal.com/news/articles/israel-and-india-show-interest-in-esas-vega-203314/ "Israel and India show interest in ESA’s Vega."] ''Flight International'', 29 November 2005.</ref> In December 2005, the Vega launcher, along with the Ariane and Soyuz launchers, were endorsed as the recognised "first choice" platforms for ESA payloads.<ref>Coppinger, Rob. [https://www.flightglobal.com/news/articles/esa-boosts-science-delays-kliper-203603/ "ESA boosts science, delays Kliper."] ''Flight International'', 13 December 2005.</ref> On 19 December 2005, the first test firing of the Vega's third stage was completed successfully at [[Salto di Quirra]], [[Sardinia]].<ref>[https://www.flightglobal.com/news/articles/vega-fires-up-on-third-stage-test-203886/ "Vega fires up on third-stage test."] ''Flight International'', 3 January, 2006.</ref> For several years, further tests would be conducted at the Sardinia site.<ref>[https://www.flightglobal.com/news/articles/vega-launcher-rocket-engine-tests-progress-with-sard-207624/ "Vega launcher rocket engine tests progress with Sardinian trial firing."] ''Flight International'', 4 July 2006.</ref><ref>Coppinger, Rob. [https://www.flightglobal.com/news/articles/rocket-propulsion-sees-triple-success-222623/ "Rocket propulsion sees triple success."] ''Flight International'', 3 April, 2008.</ref> Progress on Vega was delayed by the failure of one such test of the third stage on 28 March 2007.<ref>[https://www.flightglobal.com/news/articles/vega-third-stage-engine-fails-212964/ "Vega third stage engine fails."] ''Flight International'', 30 March 2007.</ref><ref>Coppinger, Rob. [https://www.flightglobal.com/news/articles/italian-space-agency-plans-its-relaunch-318226/ "Italian Space Agency plans its relaunch."] ''Flight International'', 31 October 2008.</ref>

During January 2007, the ESA announced that the agency was studying the use of [[Global Positioning System]] (GPS) navigation in order to support launches of the Vega and Ariane.<ref>[https://www.flightglobal.com/news/articles/gps-navigation-may-guide-europes-vega-211833/ "GPS navigation may guide Europe's Vega."] ''Flight International'', 30 January 2007.</ref> At the 2009 [[Paris Airshow]], it was revealed that the adoption of more cost-effective engine to replace the upper stages of the Vega have been postponed due to a failure to reduce the overall costs of the launcher, making it much less worthwhile to pursue.<ref>Coppinger, Rob. [https://www.flightglobal.com/news/articles/paris-air-show-commercial-soyuz-vega-launchers-fac-327883/ "PARIS AIR SHOW: Commercial Soyuz, Vega launchers face up to cost pressures."] ''Flight International'', 14 June 2009.</ref> Despite this finding, efforts to improve the efficiency of the third stage continued.<ref>Peruzzi, Luca. [https://www.flightglobal.com/news/articles/italy-has-sights-and-budget-set-firmly-on-the-co-345402/ "Italy has sights - and budget - set firmly on the cosmos."] ''Flight International'', 28 July 2010.</ref> At this point, the certification of all four stages of the Vega launch was anticipated to be achieved prior to the end of 2009, while the maiden launch itself was scheduled to take place during 2010.<ref>Peruzzi, Luca. [https://www.flightglobal.com/news/articles/paris-air-show-face-the-facts-with-avio-chief-execu-328132/ "PARIS AIR SHOW: Face the facts with Avio chief executive Orazio Ragni."] ''Flight International'', 16 June 2009.</ref> The first flight was intended to be flown with a scientific payload, rather than a 'dummy' placeholder;<ref>Coppinger, Rob. [https://www.flightglobal.com/news/articles/maiden-vega-to-fly-science-payload-to-conduct-tests-214417/ "Maiden Vega to fly science payload to conduct tests with lasers."] ''Flight International'', 5 June 2007.</ref><ref name = "jan 2012 slip"/> but had intentionally avoided a costly commercial satellite.<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/space-time-and-vegas-heavy-burden-367361/ "Space, time and Vega's heavy burden."] ''Flight International'', 26 January 2012.</ref> By late 2010, the maiden flight had been delayed into 2011.<ref>Peruzzi, Luca. [https://www.flightglobal.com/news/articles/italy-special-towards-the-stars-349620/ "Italy special: Towards the stars."] ''Flight International'', 16 November 2010.</ref>

===Into flight===
During October 2011, all major components of the first Vega rocket departed Avio's [[Colleferro]] facility, near [[Rome]], by sea for Kourou. At this point, the first launch was anticipated to occur during December 2011 or January 2012.<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/esa-counting-down-to-historic-launches-362772/ "ESA counting down to historic launches."] ''Flight International'', 17 October 2011.</ref><ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/vega-on-track-for-january-maiden-flight-from-esas-f-365888/ "Vega on track for January maiden flight from ESA's French Guiana launch site."] ''Flight International'', 13 December 2011.</ref> During early January 2012, it was reported that the launch date would slip into the following month.<ref name = "jan 2012 slip">Thisdell, Dan. [https://www.flightglobal.com/news/articles/vega-maiden-launch-could-slip-into-february-366618/ "Vega maiden launch could slip into February."] ''Flight International'', 6 January 2012.</ref><ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/fingers-crossed-and-re-crossed-as-vega-moves-toward-367369/ "Fingers crossed and re-crossed as Vega moves toward maiden flight."] ''Flight International'', 26 January 2012.</ref> On 13 February 2012, the maiden launch of the Vega rocket occurred for Kourou; it was reported as being an "apparently perfect flight".<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/vega-maiden-launch-goes-to-plan-368170/ "Vega maiden launch goes to plan."] ''Flight International'', 13 February 2012.</ref><ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/success-of-vega-rocket-flight-boosts-avio-profile-368564/ "Success of Vega rocket flight boosts Avio profile."] ''Flight International'', 22 February 2012.</ref>

During mid-2011, it was postulated that an evolved 'Europeanised' upgrade of the Vega rocket could be developed in the medium-to-long term future.<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/paris-esa-to-fire-up-next-gen-launcher-358697/ "PARIS: ESA to fire up next-gen launcher."] ''Flight International'', 24 June 2011.</ref> Following the successful maiden launch, various improvements for the Vega were postulated. The [[German Aerospace Center]] (DLR) was reportedly enthusiastic on the prospects of developing a European alternative to the Vega's final, fourth stage; however, it was widely believed that there should be no change to Vega hardware for roughly 10 years in order to consolidate operations and avoid unnecessary costs early on.<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/spaceflight-partners-look-to-enhance-vega-368664/ "SPACEFLIGHT: Partners look to enhance Vega."] ''Flight International'', 23 February 2012.</ref> The ESA was also keen to take advantage of potential commonalities between the Vega and the proposed [[Ariane 6]] heavy launcher.<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/in-focus-europes-next-rocket-has-high-hurdles-to-c-379500/ "IN FOCUS: Europe's next rocket has high hurdles to clear."] ''Flight International'', 27 November 2012.</ref>

Following on from the maiden launch, a further four flights were used to conducted under the vestiges of the VERTA programme (Vega Research and Technology Accompaniment), during which observation or scientific payloads were orbited while validating and readying the Vega rocket for more lucrative commercial operations.<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/in-focus-europe-forges-ahead-in-space-373311/ "IN FOCUS: Europe forges ahead in space."] ''Flight International'', 3 July 2012.</ref> The second launch, performed on 6 May 2012, which followed a considerably more demanding flight profile and carried the type's first commercial payload, was also successful.<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/for-flexible-vega-second-launch-a-step-up-in-comp-384870/ "For ‘flexible’ Vega, second launch a step up in complexity."] ''Flight International'', 18 April 2013.</ref> In the aftermath of this second launch, the ESA declared the Vega rocket to be "fully functional".<ref>Thisdell, Dan. [https://www.flightglobal.com/news/articles/vegas-second-success-confirms-functionality-385689/ "Vega’s second success ‘confirms functionality’."] ''Flight International'', 9 May 2013.</ref>

Since entering commercial service, Arianespace markets Vega as a launch system tailored for missions to [[Polar orbit|polar]] and [[sun-synchronous orbit|sun-synchronous]] orbits.<ref>{{cite web |url=http://www.arianespace.com/launch-services-vega/performance.asp |title=Vega — Performance |publisher=Arianespace}}</ref> During its qualification flight, Vega placed its main payload of 386.8 kg, the [[LARES (satellite)|LARES]] satellite, into a circular orbit at the altitude of 1450 km with an inclination of 69.5 degrees.<ref>I. Ciufolini et al. ''The Design of LARES: A Satellite for Testing General Relativity''. IAC-07-B4.2.07, proceedings of the 58th International Astronautical Congress, India, Hyderabad, 2007.</ref>

==Specifications==
=== Stages ===
{| class="wikitable sortable" style="margin: 1em auto 1em auto; width:50%; font-size:95%;"
|+Vega (Stages)
|- style="text-align:center; background:#BBB;"
|Parameters<ref name="avioPdf">{{cite web |url=http://www.avio.com/files/catalog/pdf/avum_78.pdf |title=Vega Satellite Launcher |publisher=[[Avio]] |accessdate=23 April 2014 |deadurl=yes |archiveurl=https://web.archive.org/web/20141101022341/http://www.avio.com/files/catalog/pdf/avum_78.pdf |archivedate=1 November 2014 |df=dmy-all }}</ref><ref name="elvP80">{{cite web |url=http://www.elv.it/en/launcher-vega/composizione-lanciatore/ |title=Vega – Launcher composition (interactive) |publisher=ELV |accessdate=23 April 2014 |deadurl=yes |archiveurl=https://web.archive.org/web/20140323093515/http://www.elv.it/en/launcher-vega/composizione-lanciatore |archivedate=23 March 2014 |df=dmy-all }}</ref>
|[[P80 (rocket stage)|P80]]
|Zefiro 23
|Zefiro 9
|AVUM
|-
| Height
| {{convert|11.7|m|ft|abbr=on}}
| {{convert|7.5|m|ft|abbr=on}}
| {{convert|3.5|m|ft|abbr=on}}
| {{convert|1.7|m|ft|abbr=on}}
|-
| Diameter
| {{convert|3|m|ft|abbr=on}}
| {{convert|1.9|m|ft|abbr=on}}
| {{convert|1.9|m|ft|abbr=on}}
| {{convert|1.9|m|ft|abbr=on}}
|-
| Propellant mass
| 88 t
| 24 t
| 10.5 t
| 0.55 t
|-
| Motor dry mass
| {{convert|7330|kg|lb|abbr=on}}
| {{convert|1950|kg|lb|abbr=on}}
| {{convert|915|kg|lb|abbr=on}}
| {{convert|131|kg|lb|abbr=on}}
|-
| Motor case mass
| {{convert|3260|kg|lb|abbr=on}}
| {{convert|900|kg|lb|abbr=on}}
| {{convert|400|kg|lb|abbr=on}}
| {{convert|16|kg|lb|abbr=on}}
|-
| Average thrust
| {{convert|2200|kN|lbf|abbr=on}}
| {{convert|871|kN|lbf|abbr=on}}
| {{convert|260|kN|lbf|abbr=on}}
| {{convert|2.42|kN|lbf|abbr=on}}
|-
| Burn time
| 110 s
| 77 s
| 120 s
| 667 s
|-
| Specific impulse
| 280 s
| 287.5 s
| 296 s
| 315.5 s
|}

===Payload===
[[Arianespace]] had indicated that the Vega launcher is able to carry {{convert|1500|kg}} to a circular [[polar orbit]] at an altitude of {{convert|700|km}}.<ref>{{cite web |url=http://www.arianespace.com/vehicle/vega/ |title=Vega — Overview |publisher=Arianespace}}</ref>

The payload fairing of the Vega was designed and is manufactured by [[RUAG Space]] of Switzerland.<ref>Coppering, Rob. [https://www.flightglobal.com/news/articles/a-significant-role-with-esa-187728/ "A significant role with ESA."] ''Flight International'', 21 September 2004.</ref> It has a diameter of 2.6 meters, a height of 7.8 meters and a mass of 400 kg.

===Three solid motor stages===
The first three stages are solid propellant engines produced by [[Avio]], that is Prime Contractor for the Vega launcher through its company ELV.<ref>{{cite web | url=http://www.aviogroup.com/en/catalog/space/propulsione_spaziale | title=Space Propulsion | publisher=Aviogroup.com | accessdate=16 February 2012}}</ref>

Each of the three engine types intended for the three stages of the Vega had to be commissioned with two test-firings – one for design evaluation and one in the final flight configuration.<ref>{{cite web | url=http://www.avio.com/files/catalog/pdf/zefiro_9_77.pdf | title=VEGA Satellite Launcher | publisher=Aviogroup.com | deadurl=yes | archiveurl=https://web.archive.org/web/20131211154448/http://www.avio.com/files/catalog/pdf/zefiro_9_77.pdf | archivedate=11 December 2013 | df=dmy-all }}</ref><ref>{{cite conference | last = Neri | first= Agostino | title = Vega Launch System Final Preparation for Qualification Flight| booktitle = Proceedings of 47th AIAA Joint Propulsion Conference| publisher =[[AIAA]] | date= 4 August 2011 | location=San Diego, California (USA) | url=https://info.aiaa.org/tac/SMG/STTC/Minutes/STTC%20Meeting%20Materials%20080411/Vega%20Program%20Status%20JPC%2011%20for%20STTC.pdf }}</ref>

====Zefiro 9====
The first engine completed was Zefiro 9, the third stage engine. The first test firing was carried out on 20 December 2005, at the [[Salto di Quirra]] Inter-force Test Range, on the [[Mediterranean Sea|Mediterranean]] coast in southeast [[Sardinia]]. The test was a complete success.<ref>[http://www.esa.int/esaCP/SEMNL68A9HE_index_0.html ESA: Successful first test for Vega's Zefiro 9 engine]</ref>

After a critical design review based on the completed first test firings,<ref>[http://www.esa.int/SPECIALS/Launchers_Home/SEMGM4SVYVE_0.html ESA: Vega Critical Design Review begins]</ref> the second test-firing of the Zefiro 9 took place at Salto di Quirra on 28 March 2007. After 35 seconds, there was a sudden drop in the motor's internal pressure, leading to an increased combustion time.<ref>[http://www.esa.int/esaCP/SEMCVFT4LZE_index_0.html ESA: Anomalous behaviour affects firing test of Vega’s Zefiro 9 motor]</ref> No public information is available for this sudden drop of internal pressure, and whether any flaws were present in the motor's design.

On 23 October 2008, an enhanced version of the Zefiro 9 with a modified nozzle design, the Zefiro 9-A, was successfully tested.<ref>{{cite web |url=http://www.esa.int/esaCP/SEM0KERTKMF_index_1.html |title=Successful first test for Vega’s Zefiro 9-A solid-fuel rocket motor |date=24 October 2008 |publisher=ESA}}</ref>

On 28 April 2009, the final qualification test firing of Zefiro 9-A took place at the Salto di Quirra Interforce Test Range in Sardinia, Italy.<ref>{{cite web |url=http://www.esa.int/esaCP/SEM688BNJTF_index_0.html |title=Successful second test for Vega’s Zefiro 9-A solid-fuel rocket motor |date=30 April 2009 |publisher=ESA}}</ref>

====Zefiro 23====
The development of the Zefiro motor was initiated by [[Avio]], partially funded by the company and partially funded by a contract from the Italian Space Agency. A Zefiro 23 forms the second stage of Vega. Its [[Carbon fiber reinforced polymer|carbon-epoxy]] case is [[Filament winding|filament-wound]] and its carbon phenolic nozzle includes a [[Reinforced carbon-carbon|carbon-carbon]] throat insert. The propellant loading is 23 tons.<ref name=caporicci104>{{cite web |url=http://www.esa.int/esapub/bulletin/bullet104/caporicci104.pdf |title=The Future of European Launchers: The ESA Perspective |author=M. Caporicci |publisher=ESA |date=November 2000}}</ref>

The Zefiro 23 second stage engine was first fired on 26 June 2006 at Salto di Quirra. This test was successful.<ref>[http://www.esa.int/esaCP/SEMH4REFWOE_Expanding_0.html ESA: Vega's second stage motor roars to life]</ref>

The second test firing of the Zefiro 23 second stage engine took place on 27 March 2008 also at Salto di Quirra. This successful test qualified the rocket engine.<ref>[http://www.esa.int/esaCP/SEMSEBR03EF_index_0.html Successful qualification firing test for Zefiro 23]</ref>

====P80====
{{Main|P80 (rocket stage)}}
The P80 is the first stage of VEGA, its name is derived from the design phase propellant weight of 80 tons that was later increased to 88 tons. The P80 includes a [[Thrust vectoring|thrust vector control (TVC)]] system (developed and made in Belgium by SABCA) consisting of two electromechanical actuators that operate a movable nozzle with flexible joint using lithium ion batteries.<ref name=caporicci104 /> The 3 m diameter case is composed of [[Carbon-fiber-reinforced polymer|graphite epoxy]] [[Filament winding|filament wound]] case and low density rubber is used for the internal insulation. The [[Rocket engine nozzle|nozzle]] is made of light low-cost carbon phenolic material; a consumable casing is used for the igniter. The [[Solid propellant#Solid propellant|solid propellant]] loaded has low binder content and high [[aluminium]] percentage ([[HTPB|HTPB 1912]]).<ref>{{cite web |url=http://www.astronautix.com/engines/p80.htm |title=Solid propellant rocket stage |website=astronautix.com |publisher=Encyclopedia Astronautica |accessdate=4 July 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20130621050752/http://www.astronautix.com/engines/p80.htm |archivedate=21 June 2013 |df=dmy-all }}</ref>

The first test firing of the P80 engine took place on 30 November 2006 in [[Kourou]], and the test was concluded successfully.<ref>[http://www.esa.int/SPECIALS/Launchers_Home/SEMTHGD4VUE_0.html ESA: Successful firing of Vega’s first-stage motor in Kourou]</ref>

The second test firing of the P80 first stage engine took place on 4 December 2007 in Kourou. Delivering a mean thrust of 190 tonnes over 111 seconds, the engine's behaviour was in line with predictions.<ref>[http://www.esa.int/SPECIALS/Launchers_Home/SEMXE029R9F_0.html ESA: Vega main engine test in Kourou]</ref>

The future version of the stage P120C, also with its name derived from the design phase propellant weight of 120 tons, will increase the propellant mass to 141-143 tons.<ref name="avioP120C">{{cite web | url=http://www.avio.com/en/vega/vega-c/vega-c-1-stadio-p120c-motor/ |title=VEGA C: 1° Stage – P120C Motor |publisher=Avio | accessdate=5 May 2017 }}</ref>

===AVUM===
The AVUM (Attitude Vernier Upper Module) [[upper stage]], developed by [[Avio]], has been designed to place the payload in the required orbit and to perform roll and attitude control functions. The AVUM consists of two modules: APM (AVUM Propulsion Module) and AAM (AVUM Avionics Module).<ref name="avioAvum">{{cite web |url=http://www.avio.com/it/catalog/space/propulsione_spaziale/avum/ |title=AVUM |publisher=[[Avio]] |accessdate=23 April 2014 |language=Italian |deadurl=yes |archiveurl=https://web.archive.org/web/20131202005015/http://www.avio.com/it/catalog/space/propulsione_spaziale/avum |archivedate=2 December 2013 |df=dmy-all }}</ref> The propulsion module uses a [[RD-843]] rocket engine [[liquid-fuel rocket]] burning pressure-fed [[Unsymmetrical dimethylhydrazine|UDMH]] and [[Dinitrogen tetroxide|nitrogen tetroxide]] as propellants. The AVUM avionics module contains the main components of the avionics sub-system of the vehicle.<ref>{{cite web | url=http://www.esa.int/SPECIALS/Vega/SEMNLCWWVUG_0.html | title=Vega Launcher | publisher=ESA | date=6 February 2012 | accessdate=16 February 2012}}</ref>

==Flights==
===Lead-up to first launch===
Enrico Saggese, at that time head of the [[Italian Space Agency]], suggested in October 2008 that the first flight of VEGA might be delayed, stating "We have to decide if we want to wait until we have another programme", and referring to plans to have German participation to develop new third and fourth stages.<ref>{{cite web |url=http://www.flightglobal.com/articles/2008/10/31/318226/italian-space-agency-plans-its-relaunch.html |title=Italian Space Agency Plans its Relaunch |work=Flight International |date=31 October 2008}}</ref>

In 2009 the first launch of the system was anticipated to take place in November 2010;<ref>{{cite web|url=http://www.flightglobal.com/blogs/hyperbola/2009/04/new-european-vega-rockets-soli.html|title=Avio: Vega's motors qualify but maiden launch slips to 2010|work=Flight International|date=29 April 2009|deadurl=yes|archiveurl=https://www.webcitation.org/68oCeAwMn?url=http://www.flightglobal.com/blogs/hyperbola/2009/04/new-european-vega-rockets-soli.html|archivedate=30 June 2012|df=dmy-all}}</ref><ref>{{cite news |url=https://www.google.com/hostednews/afp/article/ALeqM5jlKAnEb0VTqJUW7tVWXxmIrryWIQ|title=Delays seen for Soyuz, VEGA launches at Europe's Space Base |agency=AFP |date=15 June 2009}}</ref> later press suggested that the launch would slip to early 2012, until ESA publicized the launch for "end of January 2012".<ref>{{cite web |url=http://www.esa.int/SPECIALS/Launchers_Home/SEMS0T7XZVG_0.html |title= Vega moves closer to its first liftoff |publisher= ESA |date=15 December 2011 }}</ref>

===Vega launches===
The maiden flight occurred on 13 February 2012.<ref>{{cite web
|url=http://www.esa.int/Our_Activities/Launchers/Launch_vehicles/Vega3/ESA_s_new_Vega_launcher_scores_success_on_maiden_flight
|title=ESA’s new Vega launcher scores success on maiden flight
|accessdate=22 July 2014
}}</ref>
All missions are launched from [[Ensemble de Lancement Vega]] (ELV)

{| class="wikitable sortable" style="margin: 1em auto 1em auto; width:95%; font-size:95%;"
|+Vega (Launch history)
|- style="text-align:center; background:#BBB;"
! Flight №
! Date and time ([[UTC]])
! Type
! Payload
! Payload type
! Orbit
! Outcome
! Notes
! References

|-
| VV01
|2012-02-13 10:00:00
|style="text-align:center;"|Vega
|nowrap|[[LARES (satellite)|LARES]] / ALMASat 1 / [[e-st@r]] / [[Goliat]] / [[MaSat-1]] / [[PW-Sat]] / [[ROBUSTA]] / [[UniCubeSat-GG]] / [[Xatcobeo|XaTcobeo]]
|[[Satellite geodesy|Geodetic]] and [[Nanosatellite]]
|style="text-align:center;"|[[Low Earth Orbit|LEO]]
|{{Success}}
|Maiden Vega launch
|
|-
| VV02
|2013-05-07 02:06:31
|style="text-align:center;"|VERTA
|[[Proba-V]] / [[VNREDSat 1A]] / [[ESTCube-1]]

|[[Earth observation|Earth observation satellite]]
|style="text-align:center;"|[[Sun-synchronous orbit|SSO]]
|{{Success}}
|First commercial launch
|<ref name="VERTA">VERTA is an acronym for ''Vega Research and Technology Accompaniment'' and designates Vega's missions aiming ''"to demonstrate the flexibility of the Vega launch system"''. VERTA framework includes four ESA missions (Proba-V, Aeolus, LISA Pathfinder and IXV), but also some missions of National Agencies (like ASI). Sources: ESA (20 November 2013). ''[http://www.esa.int/Our_Activities/Launchers/Launch_vehicles/Vega3/VERTA_programme VERTA Programme]''; ASI (2015).''[http://www.asi.it/en/activity/earth_observation/prisma_ PRISMA Precursore IperSpettrale (Hyperspectral Precursor) of the application mission]''.</ref><ref name="vv02updates">{{cite web |url=http://www.spaceflight101.com/vega-vv02-launch-updates.html |title=Vega delivers three Satellites to Orbit to achieve second Success |date=7 May 2013 |publisher=spaceflight101 |accessdate=14 January 2014 |deadurl=yes |archiveurl=https://web.archive.org/web/20140115144957/http://www.spaceflight101.com/vega-vv02-launch-updates.html |archivedate=15 January 2014 |df=dmy-all }}</ref>

|-
| VV03
|2014-04-30 01:35:15
|style="text-align:center;"|Vega
|[[KazEOSat-1]]
|Earth observation satellite
|style="text-align:center;"|SSO
|{{Success}}
|
|<ref name="dzz-hr">{{cite web |url=http://www.kazakhstanlive.com/2.aspx?sr=100&CatID=9f9f8034-6dd6-4f7e-adcf-0f6a7c0406d9&ProdID=888e9540-30fd-479f-a0ce-3f10d4a39b48 |title=Kazakhstan to launch sastellite on new Arianespace Vega vehicle |date=22 June 2012 |author=Greg Delaney |publisher=kazakhstanlive.com |accessdate=7 May 2013}}</ref>

|-
| VV04
|2015-02-11 13:40:00
|style="text-align:center;"|VERTA
|[[Intermediate eXperimental Vehicle|IXV]]
|nowrap|[[Atmospheric entry|Reentry]] [[technology demonstration]]
|style="text-align:center;"|[[Suborbital]]
|{{Success}}
|IXV deployed on suborbital trajectory, AVUM briefly entered orbit before performing targeted de-orbit
|<ref name="IXV debut">{{cite news |last1=Bergin |first1=Chris |title=ESA’s experimental space plane gearing up for November debut |url=http://www.nasaspaceflight.com/2014/07/esas-experimental-space-plane-gearing-november/ |accessdate=3 July 2014 |publisher=NASA spaceflight |date=3 July 2014 |ref=http://www.nasaspaceflight.com/2014/07/esas-experimental-space-plane-gearing-november/}}</ref><ref>{{cite news |url=http://www.arianespace.com/news-feature-story/2014/10-17-2014-combined_missions.asp |title=The Spaceport keeps pace with Arianespace's busy mission cadence |publisher=Arianespace |date=17 October 2014 |accessdate=20 October 2014}}</ref><ref>{{cite news |url=http://www.esa.int/Our_Activities/Launchers/Launch_schedule |title=ESA launch schedule |accessdate=28 November 2014}}</ref> <ref name="ixvVega">{{cite web |url=http://www.esa.int/Our_Activities/Launchers/Vega_to_fly_ESA_experimental_reentry_vehicle |title=Vega to fly ESA experimental reentry vehicle |date=29 March 2013 |publisher=[[ESA]] |accessdate=7 May 2013}}</ref><ref>{{cite web|title=IXV – Intermediate Experimental Vehicle|url=http://www.spaceflight101.com/ixv.html|website=Spaceflight101|accessdate=2015-02-27}}</ref>

|-
| VV05
|2015-06-23 01:51:58
|style="text-align:center;"|Vega
|[[Sentinel-2A]]
|Earth observation satellite
|style="text-align:center;"|SSO
|{{Success}}
|
|<ref>[https://earth.esa.int/web/guest/missions/esa-future-missions/sentinel-2 "Sentinel-2".] ESA. Retrieved 30 April 2014.</ref><ref name=Soyuzorbits>{{cite web|title=Soyuz orbits Sentinel-1A on 7th successful launch from French Guiana|url=http://www.cnes.fr/web/CNES-en/11229-gp-soyuz-orbits-sentinel-1a-on-7th-successful-launch-from-french-guiana.php|publisher=CNES|accessdate=30 April 2014}}</ref> <ref name="arianspaceMilestones">{{cite web |url=http://www.arianespace.com/launch-services-vega/milestones.asp |title=Vega milestones |publisher=[[Arianespace]] |accessdate=7 May 2013}}</ref><ref name=ESAbooks>{{cite web|title=ESA books Eurockot Launch for Sentinel-5p Satellite|url=http://www.eurockot.com/2014/01/esa-books-eurockot-launch-for-sentinel-5p-satellite/|publisher=Eurockot Launch Services|accessdate=30 April 2014}}</ref>

|-
| VV06
|2015-12-03 04:04:00
|style="text-align:center;"|VERTA
|[[LISA Pathfinder]]
|[[Technology demonstration|Technology demonstrator]]
|style="text-align:center;"|[[Halo orbit]] [[Lagrangian point|Earth-Sun L1]]
|{{Success}}
|
|<ref name="ixvVega1">{{cite web |url=http://www.esa.int/Our_Activities/Space_Science/LISA_Pathfinder_overview |title=LISA Pathfinder overview |date=10 January 2013 |publisher=[[ESA]] |accessdate=7 May 2013}}</ref><ref>{{cite web|url=http://www.esa.int/Our_Activities/Space_Science/LISA_Pathfinder_en_route_to_gravitational_wave_demonstration|title=LISA Pathfinder enroute to gravitational wave demonstration|publisher=[[European Space Agency]]|accessdate=3 December 2015}}</ref>

|-
| VV07
|2016-09-16 01:43:35
|style="text-align:center;"|Vega
|nowrap|PeruSat-1 / 4 [[Terra Bella]] satellites

|nowrap|[[Reconnaissance satellite]] / Earth observation satellite
|style="text-align:center;"|SSO
|{{Success}}
|
|<ref name=Peruvian>{{cite news|last1=de Selding|first1=Peter B.|title=Vega To Launch Peruvian Imaging Satellite Along with Skybox Craft|url=http://spacenews.com/vega-to-launch-peruvian-imaging-satellite-along-with-skybox-craft/|accessdate=3 October 2015|publisher=Spacenews|date=25 March 2015}}</ref><ref name="optSatVenus">{{cite web |url=http://spacenews.com/vega-to-launch-skybox-satellites/ |title=Vega To Launch Skybox Satellites |date=17 March 2015 |publisher=[[SpaceNews (publication)|SpaceNews]] |accessdate=18 March 2015}}</ref>

|-
| VV08
|2016-12-05 13:51:44
|style="text-align:center;"|Vega
|[[Göktürk-1|Göktürk-1A]]
|Earth observation satellite
|style="text-align:center;"|SSO
|{{Success}}
|
|<ref name=Arianespace>{{cite web|title=Arianespace’s Vega scores its eighth success in orbiting GÖKTÜRK-1 for Turkey|url=http://www.arianespace.com/mission-update/arianespaces-vega-scores-its-eighth-success-in-orbiting-gokturk-1-for-turkey/|publisher=Arinespace|accessdate=5 December 2016}}</ref>

|-
| VV09
|2017-03-07 01:49:24
|style="text-align:center;"|Vega
|[[Sentinel 2|Sentinel 2B]]
|Earth observation satellite
|style="text-align:center;"|SSO
|{{Success}}
|
|<ref name="Project main steps">{{cite web |title=Project main steps |url=http://missions-scientifiques.cnes.fr/VENUS/ |website=cnes.fr |publisher=CNES |accessdate=3 October 2015}}</ref><ref name="optSatVenus1">{{cite web |url=http://www.arianespace.com/news-press-release/2014/2-19-2014-Contract-Optsat3000-Venus.asp |title=Arianespace to launch OPTSAT 3000 and VENµS satellites |date=19 February 2014 |publisher=[[Arianespace]] |accessdate=24 February 2014}}</ref>

|-
| VV10
|2017-08-02 01:58:33
|style="text-align:center;"|Vega
|OPSAT 3000 / [[VENµS]]
|[[IMINT]] / Earth observation satellite
|style="text-align:center;"|SSO
|{{Success}}
|
|<ref>https://spaceflightnow.com/2017/08/02/vega-launcher-achieves-on-target-deployment-of-earth-imaging-satellites/</ref>

|-
| VV11
|2017-11-08 01:42:31
|style="text-align:center;"|Vega
|Pleiades (Morocco)
|Earth observation satellite
|style="text-align:center;"|SSO
|{{Success}}
|
|<ref name=SFN>{{cite web |url=https://spaceflightnow.com/launch-schedule/ |title=Launch Schedule |last=Clark |first=Stephen |date=1 August 2017 |website=Spaceflightnow }}</ref>

|-
| VV12
| 2018-01-20
| style="text-align:center;"|VERTA
| [[ADM-Aeolus]]
| [[Weather satellite]]
| style="text-align:center;"|SSO
| {{Scheduled}}
|
| <ref name=SFN /><ref>[http://www.esa.int/Our_Activities/Observing_the_Earth/The_Living_Planet_Programme/Earth_Explorers/ADM-Aeolus/Wind_laser_survives_extremes "Wind laser survives extremes".] ESA. Retrieved 29 April 2014.</ref><ref name="2 Lidar">{{cite news|last1=de Selding|first1=Peter B.|title=Cost, Schedule Woes on 2 Lidar Missions Push ESA To Change Contract Procedures|url=http://spacenews.com/cost-schedule-woes-on-2-lidar-missions-push-esa-to-change-contract-procedures/|accessdate=3 October 2015|publisher=Spacenews|date=22 May 2015}}</ref>

|-
| VV13
| 2018
| style="text-align:center;" | Vega
| [[PRISMA (spacecraft)|PRISMA]] {{ill|TARANIS|fr}}
| Earth observation satellites
| style="text-align:center;" | SSO
| {{Planned}}
|
| <ref name=thelaunchers:vega>{{cite web|last=Depasquale|first=Francesco|title=The Launchers: Vega a winning project Capability, Opportunities and Future Prospective|url=http://www.cesmaweb.org/pdf/italinspace/Vega_De_Pasquale.pdf|accessdate=1 May 2014}}</ref><ref name=winningproject>{{cite web|last=Depasquale|first=Francesco|title=The Launchers: Vega a winning project Capability, Opportunities and Future Prospective|url=http://www.aofs.org/wp-content/uploads/2013/07/06.-Lanciatori-Ing.-Francesco-De-Pasquale-ELV.pdf|accessdate=10 December 2015}}</ref><ref name=ASIreport>{{cite web|title=ASI report to SpaceOps CaL |url=http://www.spaceops.org/images/spaceops/ASI_briefing_0513.pdf |accessdate=30 April 2014 |deadurl=yes |archiveurl=https://web.archive.org/web/20140502033026/http://www.spaceops.org/images/spaceops/ASI_briefing_0513.pdf |archivedate=2 May 2014 }}</ref><ref>[http://www.asi.it/en/activity/earth_observation/prisma_ "PRISMA".] ASI. Retrieved 29 April 2014.</ref>

|-
|
| 2018
| style="text-align:center;"|Vega
| [[Falcon Eye 1]]
| [[IMINT]]
| style="text-align:center;"|SSO (?)
| {{Planned}}
|
| <ref name=falconeye>{{cite web |url=http://space.skyrocket.de/doc_sdat/falcon-eye-1.htm |title=Falcon Eye 1, 2 |work=Gunter's Space Page |first=Gunter |last=Krebs |access-date=3 August 2017}}</ref>

|-
|
| 2018
| style="text-align:center;"|Vega
| [[Sentinel-3]]B
| Earth observation satellite
| style="text-align:center;"|SSO
| {{Planned}}
|
| <ref name=sentinel3>{{cite web|url=https://earth.esa.int/web/guest/missions/esa-eo-missions/sentinel-3|title=Sentinel-3|publisher=ESA|accessdate=11 September 2017}}</ref>

|-
|
| H2 2018
| style="text-align:center;"| Vega
| [[UniSat-7]]
| [[Technology demonstration]]
| style="text-align:center;"| SSO
| {{Planned}}
| Demonstration flight of the new Small Satellites Mission Service dispenser
| <ref>{{cite|url=http://www.esa.int/Our_Activities/Launchers/Vega_flight_opportunity_for_multiple_small_satellites |title=Vega flight opportunity for multiple small satellites|publisher=[[ESA]] |date=22 February 2017|access-date=22 February 2017}}</ref><ref name=unisat7>{{cite web |url=http://space.skyrocket.de/doc_sdat/unisat-7.htm |title=UniSat 7 |work=Gunter's Space Page |first=Gunter |last=Krebs |access-date=3 August 2017}}</ref>

|-
|
|2019
|style="text-align:center;"|Vega-C1
|TBD
|
|style="text-align:center;"|
|{{Planned}}
|Maiden flight of Vega-C
|<ref name=vega-c>{{cite web |url=http://space.skyrocket.de/doc_lau_det/vega-c.htm |title=Vega-C |work=Gunter's Space Page |first=Gunter |last=Krebs |access-date=3 August 2017}}</ref>

|-
|
|2019
|style="text-align:center;"|Vega
|[[Falcon Eye 2]]
|[[IMINT]]
|style="text-align:center;"|SSO (?)
|{{Planned}}
|
|<ref name=falconeye>{{cite web |url=http://space.skyrocket.de/doc_sdat/falcon-eye-1.htm |title=Falcon Eye 1, 2 |work=Gunter's Space Page |first=Gunter |last=Krebs |access-date=3 August 2017}}</ref>

|-
|
| 2020
| style="text-align:center;"| Vega-C1
| [[CSG (satellite)|CSG-2]]
| Earth observation satellite
| style="text-align:center;"| LEO
| {{Planned}}
|
|<ref name=csg>{{cite web |url=http://space.skyrocket.de/doc_sdat/cosmo-skymed-csg.htm |title=CSG 1, 2 (COSMO-SkyMed 2nd Gen.) |work=Gunter's Space Page |first=Gunter |last=Krebs |access-date=3 August 2017}}</ref>

|-
|
| 2020
| style="text-align:center;"| Vega-C1
| [[CERES (satellite)|CERES]] other satellite
| [[SIGINT]]
| style="text-align:center;"| SSO (?)
| {{Planned}}
|
| <ref name=arianespace-pr-2017>{{cite pr |url=http://www.arianespace.com/press-release/building-on-its-2016-successes-arianespace-looks-to-the-future-with-confidence-at-the-service-of-its-customers/ |title=Building on its 2016 successes, Arianespace looks to the future with confidence at the service of its customers |publisher=[[Arianespace]] |date=4 January 2017 |access-date=8 January 2017}}</ref>

|-
|
| 2020
| style="text-align:center;"| Vega-C1
| 2 satellites
| [[SIGINT]]
| style="text-align:center;"| SSO
| {{Planned}}
|
|

|-
|
| Q4, 2020
| style="text-align:center;"| Vega
| [[Proba-3]]
| [[Technology demonstration]] [[Sun|Solar research]]
| style="text-align:center;"| Elliptical
| {{Planned}}
|
|<ref name=proba3>{{cite web |url=http://space.skyrocket.de/doc_sdat/proba-3.htm |title=PROBA 3 |work=Gunter's Space Page |first=Gunter |last=Krebs |access-date=24 August 2017}}</ref><ref name=sfn-20170820>{{cite web |url=https://spaceflightnow.com/2017/08/20/pioneering-esa-mission-aims-to-create-artificial-solar-eclipses/ |title=Pioneering ESA mission aims to create artificial solar eclipses |last=Clark |first=Stephen |date=20 August 2017 |website=Spacefligt Now }}</ref>

|}

===Planned future launches===

The [[Italian Aerospace Research Centre]] plans to launch its "FTB-X" test vehicle<ref name="cira">{{cite web |url=http://usv.cira.it/index.php?option=com_content&task=view&id=3&Itemid=18&lang=english |title=Flying Test Beds, FTB-X}}</ref> on a Vega launcher in the future although there are no updates in the project since 2012.<ref name="malik">{{cite web |url=http://www.space.com/businesstechnology/070312_usv_droptest.html |title=Italian Firm Hails Test of Unmanned Spacecraft Prototype |author=Tariq Malik |date=12 March 2007}}</ref>

In November 2013, Arianespace ordered from ELV 10 Vega launchers, with the first to be ready for launch starting at the end of 2015. These are intended to cover more than three years of operations.<ref name="AS20131120">[http://www.arianespace.com/news-press-release/2013/11-20-2013-ELV-contract.asp Arianespace orders ten new Vega launchers from ELV] {{webarchive|url=https://web.archive.org/web/20131202224813/http://www.arianespace.com/news-press-release/2013/11-20-2013-ELV-contract.asp |date=2 December 2013 }}, [[Arianespace]] media release, 20 November 2013, accessed 22 November 2013</ref>

==Costs==
Developments costs for the Vega rocket were €710 million, with ESA spending an additional €400 million to sponsor five development flights between 2012 and 2014.<ref name="SpaceNews20120213">{{cite web|url=http://www.spacenews.com/launch/120213-vega-succeeds-debut.html|title=Europe’s Italian-led Vega Rocket Succeeds in Debut|publisher=SPACE NEWS|date=13 February 2012|first=Peter B.|last=de Selding}}{{dead link|date=November 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
Commercial launch cost have been estimated at €32 million including Arianespace's marketing and service costs or €25 million for a rocket alone, assuming launch rate of 2 per year. By increasing flight rate up to 4 per year price of an each individual launch vehicle will drop to €22 million.<ref name="SpaceWeb20120123">{{cite web |url=http://www.spacenews.com/article/vega-expected-be-price-competitive-russian-rockets|title=Vega Expected to be Price-competitive With Russian Rockets|publisher=Space News|date=23 January 2012|first=Peter B.|last=de Selding}}</ref>
{{quote|text=Our belief is that we can charge up to 20 percent more per launch than our biggest competitors and still win business because of the value we provide at the space center here and with Arianespace.|sign=Francesco De Pasquale, managing director of ELV SpA|source=''[[SpaceNews]]''<ref name="SpaceWeb20120123" />}}

==Future developments==
[[Image:Maquette Vega C DSC 0020.JPG|Mock version of Vega C at Paris Air Show 2015|thumb|75px|right]]

* Vega Consolidated ('''VEGA C''')<ref>{{cite web | url=http://www.avio.com/en/vega/vega-c/ | title=VEGA C | publisher=AVIO | accessdate=8 November 2017}}</ref>
** evolution of standard Vega;
** P120C as first stage replacing P80;
** Zefiro 40 as second stage replacing Z23;
** first launch expected in 2019.
* VEGA Evolution ('''VEGA E''')<ref>{{cite web | url=http://www.avio.com/en/vega-2/vega-e/ | title=VEGA E | publisher=AVIO | accessdate=8 November 2017}}</ref>
** evolution of Vega C;
** MIRA cryogenic [[Liquid oxygen|LOX]]/[[Liquid methane]] upperstage replacing both Zefiro 9 and AVUM;
** first launch expected in 2024.

There was a concept study for a new medium-size launcher based on Vega and [[Ariane 5]] elements. This launcher would use an Ariane 5 P230 first stage, a Vega P80 second stage and an Ariane 5 third stage using either storable or cryogenic fuel.<ref name=caporicci104 /> The addition of [[Soyuz at the Guiana Space Centre|Soyuz]] to the Arianespace launch vehicle lineup removed momentum from this initiative.{{citation needed|date=February 2012}}

The future upgraded Vega (''LYRA program'') has exceeded the feasibility study and is planned to replace the current third and fourth stages with a single low cost LOX/Liquid methane stage with a new [[guidance system]]. The purpose of the program is to upgrade the performance by about 30% without significant price increase.<ref>{{cite web | url=http://www.asi.it/en/activity/transportation/lyra | title=LIRA | VEGA evolution | publisher=Agenzia Spaziale Italiana | accessdate=17 February 2012 | deadurl=yes | archiveurl=https://web.archive.org/web/20120125045654/http://www.asi.it/en/activity/transportation/lyra | archivedate=25 January 2012 | df=dmy-all }}</ref>

On 14 February 2012, one day after the successful first launch of Vega, the German space agency moved to be included in the program. Johann-Dietrich Woerner, at that time head of the German Aerospace Agency [[German Aerospace Center|DLR]], said Germany wanted to join the project. Germany would provide a replacement for the RD-843 engine on the AVUM fourth stage, currently made in Ukraine. The Vega Launcher Manager stated that it will not fly in the near future because it takes some time to develop, but he confirmed it will be on agenda in the next meeting of ministers in late 2012. That way, all components of the rocket would be built inside the EU, excluding the Swiss made ones.<ref name="spaceflightnow"/>

The Vega first stage P120 is under consideration as booster for the first stage of the next generation [[Ariane 6]] rocket.<ref name="sfn-20121121">{{cite news |url=http://spaceflightnow.com/news/n1211/21ariane/ |title=European ministers decide to stick with Ariane 5, for now |author=Stephen Clark |publisher=Spaceflight Now |date=21 November 2012 |accessdate=22 November 2012}}</ref>

The revised Vega-C first stage, renamed ''P120C'' (Common), has been selected as [[Booster (rocketry)|booster]] for the first stage of the next generation [[Ariane 6]] rocket at the ESA Council meeting at Ministerial level in December 2014.<ref name="asiNews32582">{{cite web |url=http://www.asi.it/it/node/32582 |title=ESA Ministerial Council: a historic leap forwards for space activities |publisher=Agenzia Spaziale Italiana |date=2 December 2014 |accessdate=5 May 2017 }}</ref>

Avio is also considering a "Vega Light" that would delete the first stage of either the Vega-C or Vega-E and would be targeted at replenishing satellite constellations. The vehicle would be capable of launching between 250-300kg or 400-500kg depending on whether it was derived from a Vega-C or Vega-E respectively. <ref name="">{{cite web |url=http://aviationweek.com/awinspace/avio-considers-vega-light-mini-launcher |title=Avio Considers 'Vega Light' Mini-Launcher |publisher=Aviation Week |date=22 November 2017 |accessdate=28 November 2017 }}</ref>

==Comparable rockets==
* [[Delta II]] 7420
* [[Minotaur IV]]
* [[Minotaur-C]]
* [[Rokot]]
* [[Soyuz-2-1v]]

==See also==
{{Portal |Spaceflight}}
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]

{{Clear}}

==References==
{{reflist|3}}

==External links==
{{Commons category|Vega (rocket)}}
* [http://www.esa.int/SPECIALS/Launchers_Access_to_Space/SEMH3E67ESD_0.html Vega launcher], European Space Agency.
* [http://www.elv.it/en/ ELV – European Launch Vehicle s.p.a.]
* [http://www.avio.com/en/vega/vega/vega-launcher/ Vega Launcher, Avio]
* [http://www.esa.int/esaCP/SEM4AU0A90E_index_0.html First stone for Vega at Europe's Spaceport]
* [http://esamultimedia.esa.int/docs/VEGAbrochure.pdf Vega brochure]
* [http://www.aviogroup.com/files/catalog/pdf/motore_p80_75.pdf Vega Leaflet]
* [http://www.esa.int/esapub/bulletin/bulletin128/bul128_inbrief.pdf Vega Nozzle]
* [http://www.sourceforge.net/projects/vegasimulator Telemetry Simulator of VEGA]
* {{cite video
| date = 1 February 2012
| title = A star rocket is born
| url = https://www.youtube.com/watch?v=UNspeRxpnjs
| medium = Television production
| publisher = [[Euronews]]
| accessdate =3 February 2012
}}
* {{cite video
| date = 31 January 2012
| title = Vega's First Launch Campaign
| url = https://www.youtube.com/watch?v=YaUMSLU0aig
| publisher = [[European Space Agency|ESA]]
| accessdate =3 February 2012
}}

{{Expendable launch systems}}
{{European launch systems}}

{{DEFAULTSORT:Vega (Rocket)}}
[[Category:Space launch vehicles of Europe]]
[[Category:Solid-fuel rockets]]
[[Category:Italian Space Agency]]
[[Category:Vehicles introduced in 2012]]

Antares (rocket)

2017-11-12T18:54:33Z

Blastr42: Updated launch date

{{Use mdy dates|date=April 2017}}
{{Infobox rocket

|image = Antares A-ONE launch.2.jpg
|image_size = 250
|caption = The launch of an Antares 110 rocket

|name = Antares
|function = Medium [[expendable launch system]]
|manufacturer = [[Orbital ATK]] (main) [[Yuzhnoye Design Bureau]] (sub)
|country-origin = United States

|pcost = {{US$|472 million}} until 2012<ref name="fglobal20120430" />
|cpl = {{US$|80-85 million}}<ref>{{cite paper |url=http://www.gao.gov/assets/690/686613.pdf |title=Surplus Missile Motors: Sale Price Drives Potential Effects on DOD and Commercial Launch Providers |publisher=U.S. Government Accountability Office |page=30 |date=August 2017 |id=GAO-17-609}}</ref>
|cpl-year = 
|alt-cpl = 

|height = {{unbulleted list
| '''110/120''': {{convert|40.5|m|abbr=on}}<ref name="slr20110514"/><ref name="sf101-antares100"/>
| '''130''': {{convert|41.9|m|abbr=on}}
| '''230''': {{convert|42.5|m|abbr=on}}<ref name="sf101-antares200"/>
}}
|diameter = {{convert|3.9|m|abbr=on}}<ref name="os201112b"/><ref name="sf101-antares200"/>
|mass = {{unbulleted list
| '''100 series''': {{convert|282000|-|296000|kg|abbr=on}}<ref name="sf101-antares100"/>
| '''230''': {{convert|298000|kg|abbr=on}}<ref name="sf101-antares200"/>
}}
|stages = 2 to 3<ref name="os201112b"/>

|capacities = 
{{Infobox rocket/payload
|location = [[Low Earth orbit|LEO]]
|kilos = {{convert|6500|kg|abbr=on}}<ref name=os20140806/>
}}

|family =
|derivatives =
|comparable = [[Delta II]]

|status = {{unbulleted list
| '''100-series''': retired
| '''200-series''': operational
| '''300-series''': planned/development
}}
|sites = [[Mid-Atlantic Regional Spaceport|MARS]] [[Mid-Atlantic Regional Spaceport Launch Pad 0|LP-0A]]
|launches = 7 ('''110''': 2, '''120''': 2, '''130''': 1, '''230''': 2)
|success = 6 ('''110''': 2, '''120''': 2, '''130''': 0, '''230''': 2)
|fail = 1 ('''130''': 1)
|partial =
|other_outcome =
|first = {{unbulleted list
| '''110''': April 21, 2013<ref name="nasapr20130421" />
| '''120''': January 9, 2014<ref name="Antareshome" />
| '''130''': October 28, 2014
| '''230''': October 17, 2016
}}
|last = {{unbulleted list
| '''110''': September 18, 2013
| '''120''': July 13, 2014
| '''130''': October 28, 2014
| '''230''': November 12, 2017
}}
|payloads = [[Cygnus (spacecraft)|Cygnus]]

|stagedata = 
{{Infobox rocket/stage
|type = stage
|diff = Antares 100-series
|stageno = First
|empty = {{convert|18700|kg|abbr=on}}<ref name="sf101-antares100"/>
|gross = {{convert|260700|kg|abbr=on}}<ref name="sf101-antares100"/>
|engines = 2 × [[NK-33#Antares|AJ26-62]]<ref name="os201112a" />
|thrust = {{convert|3265|kN|lb-f|abbr=on}}<ref name="os201112a" />
|SI = '''Sea level''': 297 s '''Vacuum:''' 331 s<ref name="sf101-antares100"/>
|burntime = 235 seconds<ref name="sf101-antares100"/>
|fuel = [[RP-1]]/[[LOX]]<ref name="os201112a" />
}}
{{Infobox rocket/stage
|type = stage
|diff = Antares 200-series
|stageno = First
|empty = {{convert|20600|kg|abbr=on}}<ref name="sf101-antares200"/>
|gross = {{convert|262600|kg|abbr=on}}<ref name="sf101-antares200"/>
|engines = 2 × [[RD-191|RD-181]]
|thrust = {{convert|3844|kN|lb-f|abbr=on}}<ref name="sf101-antares200"/>
|SI = '''Sea level''': 311.9 s '''Vacuum:''' 339.2 s<ref name="sf101-antares200"/>
|burntime = 215 seconds<ref name="sf101-antares200"/>
|fuel = [[RP-1]]/[[LOX]]
}}
{{Infobox rocket/stage
|type = stage
|stageno = Second
|name = [[Castor (rocket stage)|Castor 30]]A/B/XL
|propmass = {{unbulleted list
| '''30A''': {{convert|12815|kg|abbr=on}}
| '''30B''': {{convert|12887|kg|abbr=on}}<ref name="sf101-antares100"/>
| '''30XL''': {{convert|24200|kg|abbr=on}}<ref name="sf101-antares200"/>
}}
|gross = {{unbulleted list
| '''30A''': {{convert|14035|kg|abbr=on}}
| '''30B''': {{convert|13970|kg|abbr=on}}
| '''30XL''': {{convert|26300|kg|abbr=on}}<ref name="sf101-antares100"/>
}}
|engines =
|solid = yes
|thrust = {{unbulleted list
| '''30A''': {{convert|259|kN|-2|abbr=on}}
| '''30B''': {{convert|293.4|kN|-1|abbr=on}}<ref name="os201112a" /><ref name="sf101-antares100"/>
| '''30XL''':
}}
|burntime = {{unbulleted list
| '''30A''': 136 seconds
| '''30B''': 127 seconds
| '''30XL''': 156 seconds<ref name="sf101-antares100"/><ref name="sf101-antares200"/>
}}
|fuel = [[HTPB|TP-H8299]]/aluminium<ref name="NSF-launch" />
}}
}}
'''Antares''' ({{IPAc-en|æ|n|ˈ|t|ɑː|r|iː|z}}), known during early development as '''Taurus II''', is an [[expendable launch system]] developed by [[Orbital Sciences Corporation]] (now [[Orbital ATK]]) to launch the [[Cygnus (spacecraft)|Cygnus]] spacecraft to the [[International Space Station]] as part of NASA's COTS and [[Commercial Resupply Services|CRS]] programs. Able to launch payloads heavier than {{convert|5000|kg|abbr=on}} into [[low-Earth orbit]], Antares is the largest rocket operated by Orbital ATK. Antares launches from the [[Mid-Atlantic Regional Spaceport]] and made its inaugural flight on April 21, 2013.<ref name="nasapr20130421" />

[[NASA]] awarded Orbital a [[Commercial Orbital Transportation Services]] (COTS) Space Act Agreement (SAA) in 2008 to demonstrate delivery of cargo to the [[International Space Station]]. For these COTS missions Orbital intends to use Antares to launch its [[Cygnus spacecraft]]. In addition, Antares will compete for small-to-medium missions.<ref name="avweek20080225" /> Originally designated the Taurus II, Orbital Sciences renamed the vehicle Antares, after the [[Antares|star of the same name]],<ref name="orbital20111212" /> on December 12, 2011.

The first four Antares launch attempts were successful. During the [[Cygnus CRS Orb-3|fifth launch]] on October 28, 2014, the rocket failed catastrophically, and the vehicle and payload were destroyed.<ref name="latimes20141028">{{cite news |url=http://www.latimes.com/nation/nationnow/la-nn-antares-explodes-20141028-story.html |title=Rocket bound for space station blows up just after liftoff |work=[[Los Angeles Times]] |first1=James |last1=Queally |first2=W. J. |last2=Hennigan |first3=Lauren |last3=Raab |date=October 28, 2014 |accessdate=November 8, 2014}}</ref> The failure was traced to a fault in the first stage engines. After completion of a redesign program, the rocket had a successful return to flight on October 17, 2016, delivering cargo to the ISS.

==Development==
The NASA COTS award was for [[US dollar|US$]]171 million and Orbital Sciences expected to invest an additional $150 million, split between $130 million for the booster and $20 million for the spacecraft.<ref name="Bergen" /> A [[Commercial Resupply Service]] contract of $1.9 billion for 8 flights was awarded in 2008.<ref>{{cite web | url=http://www.nasaspaceflight.com/2008/12/spacex-and-orbital-win-huge-crs-contract-from-nasa/ | title=SpaceX and Orbital win huge CRS contract from NASA | publisher=nasaspaceflight.com | date=December 23, 2008 | accessdate=February 22, 2015 | author=Chris Bergin}}</ref> As of April 2012, development costs were estimated at $472 million.<ref name="fglobal20120430" />

On June 10, 2008 it was announced that the [[Mid-Atlantic Regional Spaceport]], formerly part of the [[Wallops Flight Facility]], in [[Virginia]], would be the primary launch site for the rocket.<ref name="yesver20080609" /> [[Mid-Atlantic Regional Spaceport Launch Pad 0|Launch pad 0A]] (LP-0A), previously used for the failed [[Conestoga (rocket)|Conestoga]] rocket, would be modified to handle Antares.<ref name="spaceports20080613" /> Wallops allows launches which reach the International Space Station's orbit as effectively as those from [[Cape Canaveral]], Florida, while being less crowded.<ref name="Bergen" /><ref name="hampton20080220" /> The first Antares flight launched a Cygnus mass simulator.<ref name="Hotsuccess" />

On December 10, 2009 [[Alliant Techsystems Inc.]] (ATK) test fired their Castor 30 motor for use as the second stage of the Antares rocket.<ref name="orbital20091210" /> In March 2010 Orbital Sciences and [[Aerojet]] completed test firings of the [[NK-33]] engines.<ref name="spaceflight-now-20100315" /> On February 22, 2013 a hot fire test was successfully performed, the entire first stage being erected on the pad and held down while the engines fired for 29 seconds.<ref name="Hotsuccess" />

==Design==
[[File:Antares 110 rocket for A-ONE mission.jpg|thumb|left|An assembled Antares rocket in the Horizontal Integration Facility]]

===First stage===
The [[Multistage rocket|first stage]] of Antares burns [[RP-1]] (kerosene) and [[liquid oxygen]] (LOX). As Orbital had little experience with large liquid stages and LOX propellant, the first stage core was designed and is manufactured in Ukraine by [[Yuzhnoye Design Bureau|Yuzhnoye SDO]]<ref name="Bergen" /> and includes propellant tanks, pressurization tanks, valves, sensors, feed lines, tubing, wiring and other associated hardware.<ref name="ug12" /> Like the [[Zenit rocket|Zenit]]—also manufactured by Yuzhnoye—the Antares vehicle has a diameter of {{convert|3.9|m|in|abbr=on}} with a matching 3.9 m [[payload fairing]].<ref name="os201112b" />

====Antares 100====
The Antares 100-series first stage was powered by two [[Aerojet]] [[NK-33#Antares|AJ26]] engines. These began as [[Kuznetsov Design Bureau|Kuznetsov]] [[NK-33]] engines built in the [[Soviet Union]] in the late 1960s and early 1970s, 43 of which were purchased by Aerojet in the 1990s. 20 of these were refurbished into AJ26 engines for Antares.<ref>{{cite web|title=Antares First-stage Engines Available Long Term, Aerojet Rocketdyne Chief Says|url=http://spacenews.com/35819antares-first-stage-engines-available-long-term-aerojet-rocketdyne-chief/|website=SpaceNews.com}}</ref> Modifications included equipping the engines for [[gimbal#Rocket engines|gimballing]], adding US electronics, and qualifying the engines to fire for twice as long as designed and to operate at 108% of their original thrust.<ref name="slr20110514" /><ref name="spaceflight-now-20100315" /> Together they produced {{convert|3265|kN|-2}} of thrust at sea level and {{convert|3630|kN|-2|abbr=on}} in vacuum.<ref name="os201112a" />

Following the catastrophic failure of an AJ26 during testing at [[Stennis Space Center]] in May 2014 and the [[Cygnus CRS Orb-3|Orb-3]] launch failure in October 2014, likely caused by an engine turbopump,<ref>{{cite web|title=SpaceflightNow|url=http://spaceflightnow.com/2014/11/05/engine-turbopump-eyed-in-antares-launch-failure/|website=Engine turbopump eyed in Antares launch failure|accessdate=June 12, 2017}}</ref> the Antares 100-series was retired.

====Antares 200====
Due to concerns over corrosion, aging, and the limited supply of AJ26 engines, Orbital had selected new first stage engines. The new engines were planned to debut in 2017 and allow Orbital to bid on a [[Commercial Resupply Services 2|second major long-term contract]] for cargo resupply of the [[ISS]]. Less than one month after the loss of the Antares rocket in October 2014, Orbital announced that it would no longer fly Antares with AJ26 engines,<ref name=sfi-20141124 /> and the first flight of Antares with new first stage engines would be moved up to 2016.<ref name="spaceflight-now-20100315"/> In December 2014 Orbital Sciences announced that the Russian RD-181—a modified version of the [[RD-191]]—would replace the AJ26 on the Antares 200-series.<ref name=tass-20141031 /><ref name=sfn-20150122 /> The first flight of the re-engined Antares 230 configuration was October 17, 2016 carrying the [[Cygnus CRS OA-5]] cargo to the [[ISS]].

The Antares 200 and 300 first stages are powered by two RD-181 engines, which provide {{convert|100000|lbf|kN|order=flip}} more thrust than the dual AJ26 engines used on the Antares 100. Orbital adapted the existing core stage to accommodate the increased performance in the 200 Series, allowing Antares to deliver up to {{convert|7000|kg|abbr=on}} to low Earth orbit.<ref name="osc2014">{{cite web |title=Antares Medium-class Space Launch Vehicle factsheet |url=http://www.orbital.com/LaunchSystems/Publications/Antares_factsheet.pdf |website=orbital.com |publisher=Orbital Sciences |accessdate=December 28, 2014 |ref=FS007_06_381 |date=2014 |archiveurl=https://web.archive.org/web/20150114185402/https://www.orbital.com/LaunchSystems/Publications/Antares_factsheet.pdf |archivedate=January 14, 2015}}</ref> The surplus performance of the Antares 200-series will allow Orbital to fulfill its ISS resupply contract in only four additional flights, rather than the five that would have been required with the Antares 100-series.<ref name=aw-20141216 /><ref name=nsf-20150812/><ref name=orbatkpr-20150812a />

====Antares 300====
While the 200 series uses the RD-181 by adapting the originally ordered 100 Series stages (KB Yuzhnoye/Yuzhmash, Zenit derived),<ref name=osc2014/> it requires under-throttling the RD-181 engines, which reduces performance. Thus, the 300 series will use a new first stage core designed for the full thrust and performance of the RD-181 engine.<ref name=nsf-20150812/>

===Second stage===
The second stage is an Orbital ATK [[Castor (rocket stage)|Castor 30]]-series [[solid-fuel rocket]], developed as a derivative of the Castor 120 solid motor used as [[Minotaur-C]]'s first stage.<ref>{{cite web |url=http://www.atk.com/products-services/castor-30-a-multi-use-motor |title=CASTOR 30-A Multi-use Motor |work=ATK.com |accessdate=July 10, 2014}}</ref> The first two flights of Antares used a Castor 30A, which was replaced by the enhanced Castor 30B for subsequent flights. The Castor 30B produces {{convert|293.4|kN|-1|abbr=on|adj=on}} average and {{convert|395.7|kN|-1|abbr=on|adj=on}} maximum thrust, and uses [[electromechanical]] [[Thrust vectoring|thrust vector]] control.<ref name="os201112a" /> For increased performance, the larger Castor 30XL is available<ref name="osc2014"/> and will be used on ISS resupply flights to allow Antares to carry the Enhanced Cygnus.<ref name="os201112a" /><ref name="Chris" /><ref name="nsf20130305" />

===Third stage===
Antares offers two optional third stages, the Bi-Propellant Third Stage (BTS) and a [[Star 48]]-based third stage. BTS is derived from Orbital Sciences' GEOStar [[spacecraft bus]] and uses [[nitrogen tetroxide]] and [[hydrazine]] for propellant; it is intended to precisely place payloads into their final orbits.<ref name="os201112b" /> The Star 48-based stage uses a [[Star 48|Star 48BV]] solid rocket motor and would be used for higher energy orbits.<ref name="os201112b" />

===Fairing===
The {{convert|3.9|m|sp=us|adj=on}} diameter, {{convert|9.9|m|sp=us|adj=on}} high [[Payload fairing|fairing]] is manufactured by [[Applied Aerospace Structures Corporation]] of [[Stockton, California]], which also builds other composite structures for the vehicle, including the fairing adaptor, stage 2 motor adaptor, stage 2 interstage, payload adaptor, and avionics cylinder.<ref name="aasc" />

===NASA Commercial Resupply Services 2 : Enhancements===
On January 14, 2016 NASA awarded three cargo contracts (CRS2) to ensure the critical science, research and technology demonstrations that are informing the agency’s journey to Mars are delivered to the International Space Station (ISS) from 2019 through 2024. Orbital ATK's Cygnus was one of these contracts.<ref name="nasa20160114">{{cite web |url=https://www.nasa.gov/press-release/nasa-awards-international-space-station-cargo-transport-contracts |title=NASA Awards International Space Station Cargo Transport Contracts |work=NASA |first1=Cheryl |last1=Warner |first2=Stephanie |last2=Schierholz |date=14 January 2016 |accessdate=6 July 2017}}</ref>

According to Mark Pieczynski, Orbital ATK Vice President, Flight Systems Group, “A further improved version [of Antares for CRS2 contract] is in development which will include: Stage 1 core updates including structural reinforcements and optimization to accommodate increased loads.

“(Also) certain refinements to the RD-181 engines and CASTOR 30XL motor; and Payload accommodations improvements including a ‘pop-top’ feature incorporated in the fairing to allow late Cygnus cargo load and optimized fairing adapter structure.”

Previously, it was understood that these planned upgrades from the Antares 230 series would create a vehicle known as the Antares 300 series.

However, when asked specifically about Antares 300 series development, Mr. Pieczynski stated that Orbital ATK has “not determined to call the upgrades, we are working on, a 300 series. This is still TBD.”<ref name="spaceflight20170203">{{cite web |url=https://www.nasaspaceflight.com/2017/02/orbital-atk-2017-cygnus-antares-enhancements-2019/ |title=Orbital ATK preps Cygnus flights; Antares enhancements on track for 2019 |work=NASA SpaceFlight |first=Chris |last=Gebhardt |date=3 February 2017 |accessdate=6 July 2017}}</ref>

==Configurations and numbering==
[[File:Castor 30 test fire.jpg|right|thumbnail|Test firing of the Castor 30 second stage]]
The first two test flights used a [[Castor (rocket stage)|Castor 30A]] second stage. All subsequent flights will use either a [[Castor (rocket stage)|Castor 30B]] or [[Castor (rocket stage)|Castor 30XL]]. The rocket's configuration is indicated by a three-digit number, the first number representing the first stage, the second the type of second stage, and the third the type of third stage.<ref name="Chris" />

{| class="wikitable" style="margin: 1em auto 1em auto;"
|-
!rowspan=2|Number
!First digit
!Second digit
!Third digit
|-
!(First stage)
!(Second stage)
!(Third stage)
|-
!0
|{{n/a}}
|{{n/a}}
|No third stage
|-
!1
|Block 1 first stage (2 × [[NK-33#Antares|AJ26-62]])
|[[Castor (rocket stage)|Castor 30A]] N/A after Block 1<ref name=osc2014/>
|[[Bipropellant Third Stage|BTS]] (3 × [[IHI Corporation|IHI]] [[BT-4 (rocket engine)|BT-4]])
|-
!2
|Block 1 first stage (Adapted to RD-181) (2 × [[RD-181]])<ref name=osc2014/>
|[[Castor (rocket stage)|Castor 30B]]
|[[Star 48|Star 48BV]]
|-
!3
|Block 2 first stage (2 × RD-181)<ref name=nsf-20150812 />
|[[Castor (rocket stage)|Castor 30XL]]
|{{n/a}}
|}

==Launch history==

===Inaugural flight===
{{main|Antares A-ONE}}
Originally scheduled for 2012, the first Antares launch, designated ''A-ONE''<ref name="NSF-AONE" /> was conducted on April 21, 2013,<ref name="sfnow20130421" /> carrying the [[Antares A-ONE#Payloads|Cygnus Mass Simulator]] (a [[boilerplate (spaceflight)|boilerplate]] [[Cygnus (spacecraft)|Cygnus spacecraft]]) and four [[CubeSat]]s contracted by [[Spaceflight Incorporated]]: [[Dove 1]] for [[Planet Labs|Cosmogia Incorporated]] (now Planet Labs) and three [[PhoneSat]] satellites – [[Alexander (satellite)|Alexander]],<ref name="krebs-phonev2" /> [[Graham (satellite)|Graham]] and [[Bell (satellite)|Bell]] for NASA.<ref name="krebs-phonev1" />

Prior to the launch, a 27-second test firing of the rocket's AJ26 engines was conducted successfully on February 22, 2013, following an attempt on February 13 which was abandoned before ignition.<ref name="Hotsuccess" />

''A-ONE'' used the Antares 110 configuration, with a [[Castor 30A]] second stage and no third stage. The launch took place from [[Mid-Atlantic Regional Spaceport Launch Pad 0|Pad 0A]] of the [[Mid-Atlantic Regional Spaceport]] on [[Wallops Island]], [[Virginia]]. LP-0A was a former [[Conestoga (rocket)|Conestoga]] launch complex which had only been used once before, in 1995, for the Conestoga's only orbital launch attempt.<ref name="NSF-launch" /> Antares became the largest — and first — liquid-fuelled rocket to fly from Wallops Island, as well as the largest rocket launched by Orbital Sciences.<ref name="NSF-AONE" />

The first attempt to launch the rocket, on April 17, 2013, was [[wikt:scrub#Verb|scrubbed]] after an umbilical detached from the rocket's second stage, and a second attempt on April 20 was scrubbed due to high altitude winds.<ref name="wapo20130421" /> At the third attempt on April 21, the rocket lifted off at the beginning of its launch window. The launch window for all three attempts was three hours beginning at 21:00 [[Coordinated Universal Time|UTC]] (17:00 [[Eastern Time Zone|EDT]]), shortening to two hours at the start of the terminal count, and ten minutes later{{clarify|date=September 2013}} in the count.<ref name="NSF-launch" /><ref name="bbc20130421" />

[[File:Antares Fails to Reach Orbit with Cygnus CRS-3 after Rocket Explodes.webm|thumb|left|Video of failed Cygnus CRS Orb-3 mission]]
[[File:Aftermath of Antares Orb-3 explosion at Pad 0A (20141029a).jpg|thumb|150px|right|Pad 0A after the incident]]

===October 2014 incident===
On October 28, 2014, the attempted launch of an Antares carrying a [[Cygnus (spacecraft)|Cygnus]] cargo spacecraft on the [[Cygnus CRS Orb-3|Orb-3]] resupply mission failed catastrophically six seconds after liftoff from [[Mid-Atlantic Regional Spaceport]] at [[Wallops Flight Facility]], [[Virginia]].<ref name="sfnantares10-26-2014" /> An explosion occurred in the thrust section just as the vehicle cleared the tower, and it fell back down onto the pad. The Range Safety officer sent the destruct command just before impact.<ref name="latimes20141028"/><ref name="orb3_termination" /> There were no injuries.<ref name=cargolost /> Orbital Sciences reported that [[Mid-Atlantic Regional Spaceport Launch Pad 0|Launch Pad 0A]] "escaped significant damage,"<ref>{{cite press release |title=ISS Commercial Resupply Services Mission (Orb-3) |url=https://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/default.aspx |date=October 30, 2014 |publisher=Orbital Sciences Corporation |quote="no evidence of significant damage" |archiveurl=https://www.webcitation.org/6Tj4mG4Wp?url=https://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/default.aspx |archivedate=October 31, 2014 |deadurl=yes |df=mdy}}</ref> though initial estimates for repairs were in the $20 million range.<ref>{{cite news |url=http://spacenews.com/42620virginia-may-seek-federal-funds-for-wallops-spaceport-repairs/ |title=Virginia May Seek Federal Funds for Wallops Spaceport Repairs |work=[[SpaceNews]] |first=Jeff |last=Foust |date=November 21, 2014 |accessdate=November 5, 2017}}</ref> Orbital Sciences formed an anomaly investigation board to investigate the cause of the incident. They traced it to a failure of the first stage LOX turbopump, but could not find a specific cause. However, the refurbished NK-33 engines, originally manufactured over 40 years earlier and stored for decades, were suspected as having leaks, corrosion, or manufacturing defects that had not been detected.<ref>{{cite web |url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |title=ISS Commercial Resupply Services Mission (Orb-3) |publisher=Orbital Sciences Corporation |archivedate=October 29, 2014 |archiveurl=https://www.webcitation.org/6Tg48UMjO?url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |deadurl=no |accessdate=October 28, 2014 |df=mdy}}</ref> On October 6, 2015, almost one year after the accident, Pad 0A was restored to use. Total repair costs were about $15 million.<ref>{{cite news |url=https://spaceflightnow.com/2015/10/06/workers-complete-15-million-in-repairs-to-antares-launch-pad/ |title=Workers complete $15 million in repairs to Antares launch pad |work=Spaceflight Now |first=Stephen |last=Clark |date=October 6, 2015 |accessdate=November 5, 2017}}</ref>

Following the failure, Orbital sought to purchase launch services for its Cygnus spacecraft in order to satisfy its cargo contract with NASA,<ref name=sfi-20141124 /> and on December 9, 2014, Orbital announced that at least one, and possibly two, Cygnus flights would be launched on [[Atlas V]] rockets from [[Cape Canaveral Air Force Station]].<ref name="Atlas_V">{{cite news |url=https://www.space.com/27962-cygnus-cargo-spacecraft-new-rocket.html |title=Private Cargo Spacecraft Gets New Rocket Ride After Accident |work=Space.com |first=Miriam |last=Kramer |date=December 9, 2014 |accessdate=November 5, 2017}}</ref> As it happened, [[Cygnus CRS OA-4|Cygnus OA-4]] and [[Cygnus CRS OA-6|OA-6]] were launched with an Atlas V and the Antares 230 performed its maiden flight with [[Cygnus CRS OA-5|Cygnus OA-5]] in October 2016. One further mission was launched aboard an Atlas in April 2017 ([[Cygnus CRS OA-7|OA-7]]), fulfilling Orbital's contractual obligations towards NASA. It will be followed by the Antares 230 in regular service with [[Cygnus CRS OA-8E|OA-8E]] in November 2017 and further missions from their extended contract.

==List of missions==
''List includes only currently manifested missions. All missions are launched from [[Mid-Atlantic Regional Spaceport]] [[Mid-Atlantic Regional Spaceport Launch Pad 0|Launch Pad 0A]].''

{| class="wikitable" style="margin: 1em auto 1em auto; font-size:95%;" width="98%"
|+Antares launch history
! #
! Launch date, time ([[UTC]])
! Mission
! Payload
! Cygnus version
! Rocket version
! Ref.
! Outcome

|-
| rowspan=2 style="text-align:center;" | 1
| style="text-align:left;" nowrap="nowrap" | April 21, 2013. 21:00
| nowrap="nowrap" | [[Antares A-ONE]]
| nowrap="nowrap" | {{Unbulleted list| [[Cygnus Mass Simulator]] | [[Dove (satellite)|Dove 1]] [[Alexander (satellite)|Alexander]] [[Graham (satellite)|Graham]] [[Bell (satellite)|Bell]] }}
| Standard (mass simulator)
| nowrap="nowrap" | Antares 110
| <ref name="nasapr20130421" /><ref name="orbital201212" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | Antares test flight, using a Castor 30A second stage and no third stage.

|-
| rowspan=2 style="text-align:center;" | 2
| style="text-align:left;" nowrap="nowrap" | September 18, 2013. 14:58
| nowrap="nowrap" | [[Cygnus Orb-D1|Orb-D1]]
| nowrap="nowrap" | ''[[G. David Low]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 110
| <ref name="sfnow20130506" /><ref name="colspace20131209" /><ref name="spaceflightnow" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | Orbital Sciences COTS demonstration flight. First Cygnus mission, first mission to rendezvous with ISS, first mission to berth with ISS, second launch of Antares. The rendezvous between the new Cygnus cargo freighter and the International Space Station was delayed due to a computer data link problem,<ref name="wapo20130922" /> but the issue was resolved and berthing followed shortly thereafter.<ref name="nasasf20130928" />

|-
| rowspan=2 style="text-align:center;" | 3
| style="text-align:left;" nowrap="nowrap" | January 9, 2014. 18:07
| nowrap="nowrap" | [[Cygnus CRS Orb-1|CRS Orb-1]]
| nowrap="nowrap" | ''[[C. Gordon Fullerton]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 120
| <ref name="Antareshome" /><ref name="Chris" /><ref name="colspace20131209" /><ref name="spaceflightnow" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | First Commercial Resupply Service (CRS) mission for Cygnus, and first Antares launch using the Castor 30B upper stage.

|-
| rowspan=2 style="text-align:center;" | 4
| style="text-align:left;" nowrap="nowrap" | July 13, 2014. 16:52
| [[Cygnus CRS Orb-2|CRS Orb-2]]
| ''[[Janice Voss]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 120
| <ref name="Chris" /><ref name="spaceflightnow" /><ref name="orb2_orbital" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | Spacecraft carried {{convert|1664|kg|lb|abbr=on}} of supplies for the ISS, including research equipment, crew provisions, hardware, and science experiments.

|-
| rowspan=2 style="text-align:center;" | 5
| style="text-align:left;" nowrap="nowrap" | October 28, 2014. 22:22
| [[Cygnus CRS Orb-3|CRS Orb-3]]
| ''[[Deke Slayton]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 130
| <ref name="Chris" /><ref name="nasa20141019">{{cite web |url=http://www.nasa.gov/mission_pages/station/structure/launch/orbital.html |title=Orbital Sciences Commercial Resupply Launch |publisher=NASA |accessdate=October 19, 2014 |archiveurl=https://web.archive.org/web/20141019220903/http://www.nasa.gov/mission_pages/station/structure/launch/orbital.html |archivedate=October 19, 2014 |deadurl=no}}</ref>
| rowspan=2 {{Failure}}
|-
| colspan=6 style="background-color:#e4dfdf;" |LOX turbopump failure T+6 seconds. Rocket fell back onto the pad and exploded.<ref>https://www.nasa.gov/sites/default/files/atoms/files/orb3_irt_execsumm_0.pdf</ref><ref name="sfnantares10-26-2014">{{cite web|url=http://spaceflightnow.com/2014/10/26/live-coverage-antares-rocket-set-for-launch-monday-from-virginia/|title=Antares explodes moments after launch|work=Spaceflight Now|date=October 28, 2014|accessdate=October 28, 2014}}</ref><ref name=cargolost>{{cite news|last1=Wall|first1=Mike|title=Private Orbital Sciences Rocket Explodes During Launch, NASA Cargo Lost|url=http://www.space.com/27576-private-orbital-sciences-rocket-explosion.html|website=Space.com|publisher=Purch|accessdate=October 28, 2014|date=October 28, 2014}}</ref> First Antares launch to use Castor 30XL upper stage. In addition to supplies for the International Space Station, payload included a [[Planetary Resources]] [[Arkyd-3]] satellite and a NASA JPL/UT-Austin CubeSat mission named RACE.<ref name=psbj20141016>{{cite news |url=http://www.bizjournals.com/seattle/news/2014/10/16/first-step-toward-asteroid-mining-planetary.html?page=all |title=First step toward asteroid mining: Planetary Resources set to launch test satellite |work=Puget Sound Business Journal |first=Steve |last=Wilhelm |date=October 16, 2014 |accessdate=October 19, 2014}}</ref><ref name="RACE20141">{{cite web |url=http://cubesat.jpl.nasa.gov/projects/race/mission.html |title=RACE Mission |publisher=NASA |accessdate=October 28, 2014 |archiveurl=https://web.archive.org/web/20141019220903/http://cubesat.jpl.nasa.gov/projects/race/mission.html |archivedate=October 19, 2014 |deadurl=no}}</ref><ref name="RACE20142">{{cite web |url=http://www.ae.utexas.edu/news/features/race-space-week |title=RACE Satellite Launching to ISS |publisher=University of Texas at Austin |accessdate=October 28, 2014 |archiveurl=https://web.archive.org/web/20141019220903/http://www.ae.utexas.edu/news/features/race-space-week |archivedate=October 19, 2014 |deadurl=no}}</ref>
|-
| rowspan=2 style="text-align:center;" | 6
| style="text-align:left;" nowrap="nowrap" | October 17, 2016. 23:45
| [[Cygnus CRS OA-5|CRS OA-5]]
| ''[[Alan G. Poindexter]]'' Cygnus
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=orbatkpr-20150812a /><ref name="Chris" /><ref name="Orbital_manifest" /><ref name=rtf>{{cite web|url=http://www.orbital.com/NewsInfo/release.asp?prid=1921|title=Orbital Announces Go-Forward Plan for NASA's Commercial Resupply Services Program and the Company's Antares Launch Vehicle|website=orbital.com|publisher=Orbital Sciences Corporation|date=November 5, 2014|accessdate=November 5, 2014}}</ref><ref name=sfn_ls>{{cite web |url=http://spaceflightnow.com/launch-schedule/ |title=Spaceflight Now — Launch schedule |work=Spaceflight Now |last=Clark |first=Stephen |date=April 25, 2017 |accessdate=April 26, 2017}}</ref><ref name=sfn_ls2>{{cite web |url=https://spaceflightnow.com/2016/10/17/oa-5-mission-status-center/ |title=Spaceflight Now — Live coverage: Antares rocket returns to flight Monday |work=Spaceflight Now |last=Clark |first=Stephen |date=October 17, 2016 |accessdate=October 17, 2016}}</ref>
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | First launch of Enhanced Cygnus on Orbital's new Antares 230.

|-
| rowspan=2 style="text-align:center;" | 7
| style="text-align:left;" nowrap="nowrap" |November 12, 2017. 12:19:51
| [[Cygnus CRS OA-8E|CRS OA-8E]]
| ''[[Gene Cernan]]'' Cygnus
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=sfn_ls /><ref name=iss-calendar />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|-
| rowspan=2 style="text-align:center;" | 8
| style="text-align:left;" nowrap="nowrap" | March 2018 
| [[Cygnus CRS OA-9E|CRS OA-9E]]
|
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=iss-calendar />
| rowspan=2 {{Planned}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|-
| rowspan=2 style="text-align:center;" | 9
| style="text-align:left;" nowrap="nowrap" | October 2018 
| [[Cygnus CRS OA-10E|CRS OA-10E]]
|
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=iss-calendar />
| rowspan=2 {{Planned}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|-
| rowspan=2 style="text-align:center;" | 10
| style="text-align:left;" nowrap="nowrap" | February 2019 
| [[Cygnus CRS OA-11E|CRS OA-11E]]
|
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=iss-calendar>{{cite web |url=http://spaceflight101.com/iss/iss-calendar/ |title=International Space Station Calendar |work=Spaceflight 101 |date=April 17, 2017 |access-date=April 26, 2017}}</ref>
| rowspan=2 {{Planned}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|}

Note: [[Cygnus CRS OA-4]], the first Enhanced Cygnus mission, and [[Cygnus CRS OA-6|OA-6]] were propelled by [[Atlas V]] 401 launch vehicles while the new Antares 230 was in its final stages of development. [[Cygnus CRS OA-7]] was also switched to an [[Atlas V]] and launched on April 18, 2017.

==Launch sequence==
The following table shows a typical launch sequence of Antares-100 series rockets, such as for launching a [[Cygnus (spacecraft)|Cygnus]] spacecraft on a [[Commercial Orbital Transportation Services|cargo resupply mission]] to the International Space Station.<ref name=presskit>{{cite web |url=http://www.nasa.gov/sites/default/files/files/Orb2_PRESS_KIT.pdf |title=Orbital-2 Mission to the International Space Station Media Press Kit |publisher=NASA |date=July 2014 |accessdate=July 13, 2014}}</ref>

{| class="wikitable"
|-
! Mission time !! Event !! Altitude
|-
| T− 03:50:00 || Launch management call to stations ||
|-
| T− 03:05:00 || Poll to initiate liquid oxygen loading system chilldown ||
|-
| T− 01:30:00 || Poll for readiness to initiate propellant loading ||
|-
| T− 00:15:00 || [[Cygnus (spacecraft)|Cygnus]]/payload switched to internal power ||
|-
| T− 00:12:00 || Poll for final countdown and {{abbr|MES|Main Engine System}} medium flow chilldown ||
|-
| T− 00:11:00 || Transporter-Erector-Launcher (TEL) armed for rapid retract ||
|-
| T− 00:05:00 || Antares avionics switched to internal power ||
|-
| T− 00:03:00 || Auto-sequence start (terminal count) ||
|-
| T− 00:02:00 || Pressurize propellant tanks ||
|-
| T− 00:00:00 || Main engine ignition ||
|-
| T+ 00:00:02.1 || Liftoff || 0
|-
| T+ 00:03:55 || Main engine cut-off (MECO) || {{convert|102|km|0|abbr=on}}
|-
| T+ 00:04:01 || Stage one separation || {{convert|108|km|0|abbr=on}}
|-
| T+ 00:05:31 || Fairing separation || {{convert|168|km|0|abbr=on}}
|-
| T+ 00:05:36 || Interstage separation || {{convert|170|km|0|abbr=on}}
|-
| T+ 00:05:40 || Stage two ignition || {{convert|171|km|0|abbr=on}}
|-
| T+ 00:07:57 || Stage two burnout || {{convert|202|km|0|abbr=on}}
|-
| T+ 00:09:57 || Payload separation || {{convert|201|km|0|abbr=on}}
|}

==See also==
{{Portal|Spaceflight}}
* [[Comparison of orbital launchers families]]
* [[Minotaur-C]]
* [[Falcon 9]]

==References==
{{Reflist |30em |refs=
<ref name=slr20110514>{{cite web |url=http://www.spacelaunchreport.com/taurus2.html |title=Taurus 2 |work=Space Launch Report |first=Ed |last=Kyle |date=May 14, 2011}}</ref>

<ref name=os201112b>{{cite web |url=http://www.orbital.com/NewsInfo/Publications/Antares_fact.pdf |title=Antares Medium-class Launch Vehicle: Fact Sheet |format=PDF |publisher=Orbital Sciences Corporation |year=2013 |accessdate=April 25, 2013 |archiveurl=https://web.archive.org/web/20130603115601/http://www.orbital.com/NewsInfo/Publications/Antares_fact.pdf |archivedate=June 3, 2013}}</ref>

<ref name="os20140806">{{cite press release |url=http://www.orbital.com/LaunchSystems/SpaceLaunchVehicles/Antares |title=Antares |publisher=Orbital Sciences Corporation|accessdate=August 5, 2014}}</ref>

<ref name="sf101-antares100">{{cite web|title=Antares (100 Series)|url=http://spaceflight101.com/spacerockets/antares-100-series/|website=SpaceFlight101|accessdate=May 5, 2016}}</ref>

<ref name="sf101-antares200">{{Cite web|url=http://spaceflight101.com/spacerockets/antares-200-series/|title=Antares 200 Series – Rockets|website=spaceflight101.com|access-date=November 7, 2016}}</ref>

<ref name="nasapr20130421">{{cite press release |url=http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-114_Antares_launches.html |title=NASA Partner Orbital Sciences Test Launches Antares Rocket |publisher=NASA |first=Trent J. |last=Perrotto |date=April 21, 2013 |accessdate=April 25, 2013}}</ref>

<ref name="Antareshome">{{Cite web |url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-1/ |title=ISS Commercial Resupply Services Mission (Orb-1) |publisher=Orbital Sciences Corporation |accessdate=January 8, 2014}}</ref>

<ref name="os201112a">{{cite web |url=http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdf |title=Antares Medium-Class Launch Vehicle: Brochure |format=PDF |publisher=Orbital Sciences Corporation |year=2013 |accessdate=April 25, 2012|archiveurl=https://web.archive.org/web/20140209070336/http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdf|archivedate=February 9, 2014 }}</ref>

<ref name="NSF-launch">{{cite news |url=http://www.nasaspaceflight.com/2013/04/orbital-antares-debut-launch-attempt/ |title=Antares conducts a flawless maiden launch |work=NASA Spaceflight |first=William |last=Graham |date=April 21, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="avweek20080225">{{cite journal |title=none|journal=Aviation Week and Space Technology |page=22 |date=February 25, 2008}}</ref>

<ref name="orbital20111212">{{cite press release |url=http://www.orbital.com/NewsInfo/release.asp?prid=798 |title=Orbital Selects "Antares" as Permanent Name for New Rocket Created by the Taurus II R&D Program |publisher=Orbital Sciences Corporation |first=Barron |last=Beneski |date=December 12, 2011}}</ref>

<ref name="Bergen">{{cite news |title=none|work=Space News |first=Chris |last=Bergin |page=12 |date=February 25, 2008}}</ref>

<ref name="fglobal20120430">{{cite news |url=http://www.flightglobal.com/news/articles/orbital-sciences-development-costs-increase-371291/ |title=Orbital Sciences development costs increase |work=Flight International ''via'' Flightglobal.com |first=Zach |last=Rosenberg |date=April 30, 2012}}</ref>

<ref name="yesver20080609">{{cite press release |url=http://www.yesvirginia.org/about_us/NewsArticle.aspx?newsid=945 |title=Governor Kaine announces 125 new jobs for Virginia |publisher=Commonwealth of Virginia ''via'' YesVirginia.org |first=Gordon |last=Hickey |date=June 9, 2008}}</ref>

<ref name="spaceports20080613">{{cite web|url=http://spaceports.blogspot.com/2008/06/taurus-2-launch-pad-to-be-ready-in-18.html |title=Taurus-2 Launch Pad to be Ready in 18-Months at Wallops Island Spaceport |work=Spaceports |publisher=Blogspot.com |first=Jack |last=Kennedy |date=June 13, 2008}}</ref>

<ref name="hampton20080220">{{cite news |url=http://hamptonroads.com/2008/02/wallops-big-role-firms-nasa-contract |title=Wallops up for big role with firm's NASA contract |work=The Virginian-Pilot ''via'' HamptonRoads.com |first=Jon W. |last=Glass |date=February 20, 2008}}</ref>

<ref name="Hotsuccess">{{cite news |url=http://www.nasaspaceflight.com/2013/02/hot-fire-success-orbitals-antares/ |title=Hot fire success for Orbital's Antares |work=NASA Spaceflight |first=Chris |last=Bergin |date=February 22, 2013 |accessdate=February 23, 2013}}</ref>

<ref name="orbital20091210">{{cite press release |url=http://www.orbital.com/NewsInfo/release.asp?prid=712 |title=Second Stage Rocket Motor Of Orbital's Taurus II Launcher Successfully Ground Tested |publisher=Orbital Sciences Corporation |first=Barron |last=Beneski |date=December 10, 2009}}</ref>

<ref name=spaceflight-now-20100315>{{cite news |url=http://spaceflightnow.com/news/n1003/15nk33/ |title=Aerojet confirms Russian engine is ready for duty |work=Spaceflight Now |first=Stephen |last=Clark |date=March 15, 2010 |accessdate=March 18, 2010 |archiveurl=https://web.archive.org/web/20100322200821/http://www.spaceflightnow.com/news/n1003/15nk33/ |archivedate=March 22, 2010 |deadurl=no}}</ref>

<ref name=ug12>{{cite web |url=http://www.orbital.com/NewsInfo/Publications/Antares_Guide.pdf |title=Antares User's Guide, Rev. 1.2 |format=PDF |publisher=Orbital Sciences Corporation |date=December 2009}}</ref>

<ref name="aasc">{{cite web |url=https://www.aascworld.com/Antares/service--1211796061/program.html |title=Antares Launch Vehicle |publisher=Applied Aerospace Structures Corporation |accessdate=April 26, 2014}}</ref>

<ref name="Chris">{{cite news |url=http://www.nasaspaceflight.com/2012/02/orbital-upbeat-ahead-of-antares-debut/ |title=Space industry giants Orbital upbeat ahead of Antares debut |work=NASA Spaceflight |first=Chris |last=Bergin |date=February 22, 2012 |accessdate=March 29, 2012}}</ref>

<ref name="nsf20130305">{{cite news |url=http://www.nasaspaceflight.com/2013/03/castor-30xl-prepares-static-fire-antares-boost/ |title=CASTOR 30XL prepares for static fire ahead of providing Antares boost |work=NASA Spaceflight |first=Chris |last=Bergin |accessdate=March 7, 2013 |date=March 5, 2013}}</ref>

<ref name="NSF-AONE">{{cite news |url=http://www.nasaspaceflight.com/2013/03/orbitals-antares-debut-a-one-mission-april/ |title=Stars align for Orbital's Antares – A-One debut set for mid-April |work=NASA Spaceflight |first=Chris |last=Bergin |date=March 17, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="sfnow20130421">{{cite news |url=http://www.spaceflightnow.com/antares/demo/130421launch/ |title=Antares test launch paves new highway to space station |work=Spaceflight Now |first=Stephen |last=Clark |date=April 21, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="krebs-phonev2">{{cite web |url=http://space.skyrocket.de/doc_sdat/phonesat-v2.htm |title=PhoneSat v2 |work=Gunter's Space Page |first=Gunter |last=Krebs |accessdate=April 22, 2013}}</ref>

<ref name="krebs-phonev1">{{cite web |url=http://space.skyrocket.de/doc_sdat/phonesat-v1.htm |title=PhoneSat v1 |work=Gunter's Space Page |first=Gunter |last=Krebs |accessdate=April 22, 2013}}</ref>

<ref name="wapo20130421">{{cite news |url=https://www.washingtonpost.com/local/wind-postpones-rocket-launch-at-wallops-flight-facility/2013/04/20/8d2c9f6c-aa15-11e2-a8e2-5b98cb59187f_story.html |title=Wind postpones rocket launch at Wallops Flight Facility |newspaper=[[The Washington Post]] |last=Weil |first=Martin |date=April 21, 2013}}</ref>

<ref name="bbc20130421">{{Cite news |url=http://www.bbc.co.uk/news/science-environment-22193330 |title=Orbital's Antares rocket makes test flight |work=BBC News |first=Jonathan |last=Amos |date=April 21, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="orbital201212">{{cite web |url=http://www.orbital.com/Antares-Cygnus/ |title=Antares Cold Flow Testing Begins and Antares A-ONE Gets All Dressed Up |publisher=Orbital Sciences Corporation |date=December 2012 |accessdate=March 5, 2013|archiveurl=https://web.archive.org/web/20130306151415/http://www.orbital.com/Antares-Cygnus/ |archivedate=March 6, 2013}}</ref>

<ref name="wapo20130922">{{cite news |url=https://www.washingtonpost.com/national/health-science/computer-mishap-delays-space-station-supply-ship-cygnus/2013/09/22/69145610-23a0-11e3-b75d-5b7f66349852_story.html |title=Computer mishap delays space station supply ship Cygnus |work=[[The Washington Post]] |first=Marcia |last=Dunn |date=September 22, 2013 |accessdate=September 22, 2013}}</ref>

<ref name="nasasf20130928">{{cite news |url=http://www.nasaspaceflight.com/2013/09/cygnus-second-attempt-berth-iss/ |title=Orbital’s Cygnus successfully berthed on the ISS |work=NASA Spaceflight |first=Chris |last=Bergin |date=September 28, 2013 |accessdate=October 8, 2013}}</ref>

<ref name="sfnow20130506">{{cite news |url=http://spaceflightnow.com/antares/cots1/130506schedule/ |title=First flight of Cygnus cargo craft delayed to September |work=Spaceflight Now |first=Stephen |last=Clark |date=May 6, 2013 |accessdate=August 7, 2013}}</ref>

<ref name="colspace20131209">{{cite news |url=http://www.collectspace.com/news/news-120913a.html |title=Orbital names next space station freighter for late pilot-astronaut |work=CollectSpace.com |first=Robert Z. |last=Pearlman |date=December 9, 2013 |accessdate=December 9, 2013}}</ref>

<ref name="spaceflightnow">{{cite web |url=http://spaceflightnow.com/tracking/index.html |title=Worldwide launch schedule |work=Spaceflight Now |accessdate=August 9, 2013 |archiveurl=https://web.archive.org/web/20130811033415/http://www.spaceflightnow.com/tracking/index.html |archivedate=August 11, 2013 |deadurl=yes}}</ref>

<ref name="Orbital_manifest">{{cite web |url=http://www.orbital.com/Antares-Cygnus/Missions/ |title=Launch Manifest |publisher=Orbital Sciences Corporation |accessdate=December 8, 2013 |archiveurl=https://web.archive.org/web/20131211023414/http://www.orbital.com/Antares-Cygnus/Missions/ |archivedate=December 11, 2013 |deadurl=yes}}</ref>

<ref name=orb2_orbital>{{cite web |url=https://www.orbital.com/NewsInfo/MissionUpdates/Orb-2/ |title=ISS Commercial Resupply Services Mission (Orb-2) |publisher=Orbital Sciences Corporation |year=2014 |accessdate=July 13, 2014 |archiveurl=https://web.archive.org/web/20140407074542/http://www.orbital.com/NewsInfo/MissionUpdates/Orb-2/ |archivedate=April 7, 2014}}</ref>

<ref name=orb3_termination>{{cite web |url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |title=ISS Commercial Resupply Services Mission (Orb-3) |publisher=Orbital Sciences Corporation |year=2014 |accessdate=October 31, 2014 |archiveurl=https://web.archive.org/web/20141031051957/http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |archivedate=October 31, 2014}}</ref>

<ref name=nsf-20150812>{{cite news |url=http://www.nasaspaceflight.com/2015/08/orb-4-cygnus-set-atlas-v-ride-ahead-antares-return/ |title=Cygnus set for December Atlas V ride ahead of Antares return |website=NASA Spaceflight |first=Chris |last=Bergin |quote=“LSP Vehicle Systems Engineering, Propulsion Engineering, Stress, Avionics and SMA (Safety and Mission Assurance) participated in the Antares Stage 1 CDR for the modifications necessary to integrate the RD-181 engine at both the 230 and 330 thrust levels.” |date=August 7, 2015 |accessdate=August 12, 2015}}</ref>

<ref name=orbatkpr-20150812a>{{cite web |url=http://www.orbitalatk.com/news-room/feature-stories/CRSUpdate/default.aspx |title=Orbital ATK Team on Track for Fall 2015 Cygnus Mission and Antares Return to Flight in 2016 |publisher=[[Orbital ATK]] |date=August 12, 2015 |accessdate=August 12, 2015}}</ref>

<ref name=sfi-20141124>{{cite news |title=Orbital’s Cygnus – on a SpaceX Falcon 9? |url=http://www.spaceflightinsider.com/missions/commercial/orbitals-cygnus-spacex-falcon-9/ |accessdate=November 28, 2014 |work=spaceflightinsider.com |date=November 24, 2014 |quote=''Orbital has announced that it is planning to use another engine on Antares and that it will likely not use any more of the 40-year-old AJ-26 engines on the rocket’s next flight – which Orbital hopes to conduct in 2016.'' }}</ref>

<ref name=tass-20141031>{{cite news |url=http://en.itar-tass.com/non-political/757591 |title=Orbital Sciences likely to choose Russian engine for new Antares rocket |work=TASS |date=October 31, 2014 |accessdate=October 31, 2014}}</ref>

<ref name=sfn-20150122>{{Cite web |url = http://spaceflightnow.com/2015/01/22/orbital-sciences-signs-contract-for-new-antares-engines/ |title = Orbital Sciences signs contract for new Antares engines |date=January 22, 2015 |accessdate=June 27, 2017 |website = Spaceflight Now}}</ref>

<ref name=aw-20141216>{{cite news |last1=Morring |first1=Frank, Jr. |title=Antares Upgrade Will Use RD-181s In Direct Buy From Energomash |url=http://aviationweek.com/space/antares-upgrade-will-use-rd-181s-direct-buy-energomash |accessdate=December 28, 2014 |work=Aviation Week |date=December 16, 2014 }}</ref>

}}

==External links==
{{Commons category|Antares (rocket)}}
* {{Official website|http://www.orbitalatk.com/products-services/antares}}

{{Cygnus spaceflights}}
{{Expendable launch systems}}
{{US launch systems}}

{{Use American English|date=January 2014}}

[[Category:Antares (rocket family)| ]]
[[Category:Articles containing video clips]]
[[Category:Vehicles introduced in 2013]]

Antares (rocket)

2017-11-12T18:52:58Z

Blastr42: Updated launch history numbers.

{{Use mdy dates|date=April 2017}}
{{Infobox rocket

|image = Antares A-ONE launch.2.jpg
|image_size = 250
|caption = The launch of an Antares 110 rocket

|name = Antares
|function = Medium [[expendable launch system]]
|manufacturer = [[Orbital ATK]] (main) [[Yuzhnoye Design Bureau]] (sub)
|country-origin = United States

|pcost = {{US$|472 million}} until 2012<ref name="fglobal20120430" />
|cpl = {{US$|80-85 million}}<ref>{{cite paper |url=http://www.gao.gov/assets/690/686613.pdf |title=Surplus Missile Motors: Sale Price Drives Potential Effects on DOD and Commercial Launch Providers |publisher=U.S. Government Accountability Office |page=30 |date=August 2017 |id=GAO-17-609}}</ref>
|cpl-year = 
|alt-cpl = 

|height = {{unbulleted list
| '''110/120''': {{convert|40.5|m|abbr=on}}<ref name="slr20110514"/><ref name="sf101-antares100"/>
| '''130''': {{convert|41.9|m|abbr=on}}
| '''230''': {{convert|42.5|m|abbr=on}}<ref name="sf101-antares200"/>
}}
|diameter = {{convert|3.9|m|abbr=on}}<ref name="os201112b"/><ref name="sf101-antares200"/>
|mass = {{unbulleted list
| '''100 series''': {{convert|282000|-|296000|kg|abbr=on}}<ref name="sf101-antares100"/>
| '''230''': {{convert|298000|kg|abbr=on}}<ref name="sf101-antares200"/>
}}
|stages = 2 to 3<ref name="os201112b"/>

|capacities = 
{{Infobox rocket/payload
|location = [[Low Earth orbit|LEO]]
|kilos = {{convert|6500|kg|abbr=on}}<ref name=os20140806/>
}}

|family =
|derivatives =
|comparable = [[Delta II]]

|status = {{unbulleted list
| '''100-series''': retired
| '''200-series''': operational
| '''300-series''': planned/development
}}
|sites = [[Mid-Atlantic Regional Spaceport|MARS]] [[Mid-Atlantic Regional Spaceport Launch Pad 0|LP-0A]]
|launches = 7 ('''110''': 2, '''120''': 2, '''130''': 1, '''230''': 2)
|success = 6 ('''110''': 2, '''120''': 2, '''130''': 0, '''230''': 2)
|fail = 1 ('''130''': 1)
|partial =
|other_outcome =
|first = {{unbulleted list
| '''110''': April 21, 2013<ref name="nasapr20130421" />
| '''120''': January 9, 2014<ref name="Antareshome" />
| '''130''': October 28, 2014
| '''230''': October 17, 2016
}}
|last = {{unbulleted list
| '''110''': September 18, 2013
| '''120''': July 13, 2014
| '''130''': October 28, 2014
| '''230''': October 17, 2016
}}
|payloads = [[Cygnus (spacecraft)|Cygnus]]

|stagedata = 
{{Infobox rocket/stage
|type = stage
|diff = Antares 100-series
|stageno = First
|empty = {{convert|18700|kg|abbr=on}}<ref name="sf101-antares100"/>
|gross = {{convert|260700|kg|abbr=on}}<ref name="sf101-antares100"/>
|engines = 2 × [[NK-33#Antares|AJ26-62]]<ref name="os201112a" />
|thrust = {{convert|3265|kN|lb-f|abbr=on}}<ref name="os201112a" />
|SI = '''Sea level''': 297 s '''Vacuum:''' 331 s<ref name="sf101-antares100"/>
|burntime = 235 seconds<ref name="sf101-antares100"/>
|fuel = [[RP-1]]/[[LOX]]<ref name="os201112a" />
}}
{{Infobox rocket/stage
|type = stage
|diff = Antares 200-series
|stageno = First
|empty = {{convert|20600|kg|abbr=on}}<ref name="sf101-antares200"/>
|gross = {{convert|262600|kg|abbr=on}}<ref name="sf101-antares200"/>
|engines = 2 × [[RD-191|RD-181]]
|thrust = {{convert|3844|kN|lb-f|abbr=on}}<ref name="sf101-antares200"/>
|SI = '''Sea level''': 311.9 s '''Vacuum:''' 339.2 s<ref name="sf101-antares200"/>
|burntime = 215 seconds<ref name="sf101-antares200"/>
|fuel = [[RP-1]]/[[LOX]]
}}
{{Infobox rocket/stage
|type = stage
|stageno = Second
|name = [[Castor (rocket stage)|Castor 30]]A/B/XL
|propmass = {{unbulleted list
| '''30A''': {{convert|12815|kg|abbr=on}}
| '''30B''': {{convert|12887|kg|abbr=on}}<ref name="sf101-antares100"/>
| '''30XL''': {{convert|24200|kg|abbr=on}}<ref name="sf101-antares200"/>
}}
|gross = {{unbulleted list
| '''30A''': {{convert|14035|kg|abbr=on}}
| '''30B''': {{convert|13970|kg|abbr=on}}
| '''30XL''': {{convert|26300|kg|abbr=on}}<ref name="sf101-antares100"/>
}}
|engines =
|solid = yes
|thrust = {{unbulleted list
| '''30A''': {{convert|259|kN|-2|abbr=on}}
| '''30B''': {{convert|293.4|kN|-1|abbr=on}}<ref name="os201112a" /><ref name="sf101-antares100"/>
| '''30XL''':
}}
|burntime = {{unbulleted list
| '''30A''': 136 seconds
| '''30B''': 127 seconds
| '''30XL''': 156 seconds<ref name="sf101-antares100"/><ref name="sf101-antares200"/>
}}
|fuel = [[HTPB|TP-H8299]]/aluminium<ref name="NSF-launch" />
}}
}}
'''Antares''' ({{IPAc-en|æ|n|ˈ|t|ɑː|r|iː|z}}), known during early development as '''Taurus II''', is an [[expendable launch system]] developed by [[Orbital Sciences Corporation]] (now [[Orbital ATK]]) to launch the [[Cygnus (spacecraft)|Cygnus]] spacecraft to the [[International Space Station]] as part of NASA's COTS and [[Commercial Resupply Services|CRS]] programs. Able to launch payloads heavier than {{convert|5000|kg|abbr=on}} into [[low-Earth orbit]], Antares is the largest rocket operated by Orbital ATK. Antares launches from the [[Mid-Atlantic Regional Spaceport]] and made its inaugural flight on April 21, 2013.<ref name="nasapr20130421" />

[[NASA]] awarded Orbital a [[Commercial Orbital Transportation Services]] (COTS) Space Act Agreement (SAA) in 2008 to demonstrate delivery of cargo to the [[International Space Station]]. For these COTS missions Orbital intends to use Antares to launch its [[Cygnus spacecraft]]. In addition, Antares will compete for small-to-medium missions.<ref name="avweek20080225" /> Originally designated the Taurus II, Orbital Sciences renamed the vehicle Antares, after the [[Antares|star of the same name]],<ref name="orbital20111212" /> on December 12, 2011.

The first four Antares launch attempts were successful. During the [[Cygnus CRS Orb-3|fifth launch]] on October 28, 2014, the rocket failed catastrophically, and the vehicle and payload were destroyed.<ref name="latimes20141028">{{cite news |url=http://www.latimes.com/nation/nationnow/la-nn-antares-explodes-20141028-story.html |title=Rocket bound for space station blows up just after liftoff |work=[[Los Angeles Times]] |first1=James |last1=Queally |first2=W. J. |last2=Hennigan |first3=Lauren |last3=Raab |date=October 28, 2014 |accessdate=November 8, 2014}}</ref> The failure was traced to a fault in the first stage engines. After completion of a redesign program, the rocket had a successful return to flight on October 17, 2016, delivering cargo to the ISS.

==Development==
The NASA COTS award was for [[US dollar|US$]]171 million and Orbital Sciences expected to invest an additional $150 million, split between $130 million for the booster and $20 million for the spacecraft.<ref name="Bergen" /> A [[Commercial Resupply Service]] contract of $1.9 billion for 8 flights was awarded in 2008.<ref>{{cite web | url=http://www.nasaspaceflight.com/2008/12/spacex-and-orbital-win-huge-crs-contract-from-nasa/ | title=SpaceX and Orbital win huge CRS contract from NASA | publisher=nasaspaceflight.com | date=December 23, 2008 | accessdate=February 22, 2015 | author=Chris Bergin}}</ref> As of April 2012, development costs were estimated at $472 million.<ref name="fglobal20120430" />

On June 10, 2008 it was announced that the [[Mid-Atlantic Regional Spaceport]], formerly part of the [[Wallops Flight Facility]], in [[Virginia]], would be the primary launch site for the rocket.<ref name="yesver20080609" /> [[Mid-Atlantic Regional Spaceport Launch Pad 0|Launch pad 0A]] (LP-0A), previously used for the failed [[Conestoga (rocket)|Conestoga]] rocket, would be modified to handle Antares.<ref name="spaceports20080613" /> Wallops allows launches which reach the International Space Station's orbit as effectively as those from [[Cape Canaveral]], Florida, while being less crowded.<ref name="Bergen" /><ref name="hampton20080220" /> The first Antares flight launched a Cygnus mass simulator.<ref name="Hotsuccess" />

On December 10, 2009 [[Alliant Techsystems Inc.]] (ATK) test fired their Castor 30 motor for use as the second stage of the Antares rocket.<ref name="orbital20091210" /> In March 2010 Orbital Sciences and [[Aerojet]] completed test firings of the [[NK-33]] engines.<ref name="spaceflight-now-20100315" /> On February 22, 2013 a hot fire test was successfully performed, the entire first stage being erected on the pad and held down while the engines fired for 29 seconds.<ref name="Hotsuccess" />

==Design==
[[File:Antares 110 rocket for A-ONE mission.jpg|thumb|left|An assembled Antares rocket in the Horizontal Integration Facility]]

===First stage===
The [[Multistage rocket|first stage]] of Antares burns [[RP-1]] (kerosene) and [[liquid oxygen]] (LOX). As Orbital had little experience with large liquid stages and LOX propellant, the first stage core was designed and is manufactured in Ukraine by [[Yuzhnoye Design Bureau|Yuzhnoye SDO]]<ref name="Bergen" /> and includes propellant tanks, pressurization tanks, valves, sensors, feed lines, tubing, wiring and other associated hardware.<ref name="ug12" /> Like the [[Zenit rocket|Zenit]]—also manufactured by Yuzhnoye—the Antares vehicle has a diameter of {{convert|3.9|m|in|abbr=on}} with a matching 3.9 m [[payload fairing]].<ref name="os201112b" />

====Antares 100====
The Antares 100-series first stage was powered by two [[Aerojet]] [[NK-33#Antares|AJ26]] engines. These began as [[Kuznetsov Design Bureau|Kuznetsov]] [[NK-33]] engines built in the [[Soviet Union]] in the late 1960s and early 1970s, 43 of which were purchased by Aerojet in the 1990s. 20 of these were refurbished into AJ26 engines for Antares.<ref>{{cite web|title=Antares First-stage Engines Available Long Term, Aerojet Rocketdyne Chief Says|url=http://spacenews.com/35819antares-first-stage-engines-available-long-term-aerojet-rocketdyne-chief/|website=SpaceNews.com}}</ref> Modifications included equipping the engines for [[gimbal#Rocket engines|gimballing]], adding US electronics, and qualifying the engines to fire for twice as long as designed and to operate at 108% of their original thrust.<ref name="slr20110514" /><ref name="spaceflight-now-20100315" /> Together they produced {{convert|3265|kN|-2}} of thrust at sea level and {{convert|3630|kN|-2|abbr=on}} in vacuum.<ref name="os201112a" />

Following the catastrophic failure of an AJ26 during testing at [[Stennis Space Center]] in May 2014 and the [[Cygnus CRS Orb-3|Orb-3]] launch failure in October 2014, likely caused by an engine turbopump,<ref>{{cite web|title=SpaceflightNow|url=http://spaceflightnow.com/2014/11/05/engine-turbopump-eyed-in-antares-launch-failure/|website=Engine turbopump eyed in Antares launch failure|accessdate=June 12, 2017}}</ref> the Antares 100-series was retired.

====Antares 200====
Due to concerns over corrosion, aging, and the limited supply of AJ26 engines, Orbital had selected new first stage engines. The new engines were planned to debut in 2017 and allow Orbital to bid on a [[Commercial Resupply Services 2|second major long-term contract]] for cargo resupply of the [[ISS]]. Less than one month after the loss of the Antares rocket in October 2014, Orbital announced that it would no longer fly Antares with AJ26 engines,<ref name=sfi-20141124 /> and the first flight of Antares with new first stage engines would be moved up to 2016.<ref name="spaceflight-now-20100315"/> In December 2014 Orbital Sciences announced that the Russian RD-181—a modified version of the [[RD-191]]—would replace the AJ26 on the Antares 200-series.<ref name=tass-20141031 /><ref name=sfn-20150122 /> The first flight of the re-engined Antares 230 configuration was October 17, 2016 carrying the [[Cygnus CRS OA-5]] cargo to the [[ISS]].

The Antares 200 and 300 first stages are powered by two RD-181 engines, which provide {{convert|100000|lbf|kN|order=flip}} more thrust than the dual AJ26 engines used on the Antares 100. Orbital adapted the existing core stage to accommodate the increased performance in the 200 Series, allowing Antares to deliver up to {{convert|7000|kg|abbr=on}} to low Earth orbit.<ref name="osc2014">{{cite web |title=Antares Medium-class Space Launch Vehicle factsheet |url=http://www.orbital.com/LaunchSystems/Publications/Antares_factsheet.pdf |website=orbital.com |publisher=Orbital Sciences |accessdate=December 28, 2014 |ref=FS007_06_381 |date=2014 |archiveurl=https://web.archive.org/web/20150114185402/https://www.orbital.com/LaunchSystems/Publications/Antares_factsheet.pdf |archivedate=January 14, 2015}}</ref> The surplus performance of the Antares 200-series will allow Orbital to fulfill its ISS resupply contract in only four additional flights, rather than the five that would have been required with the Antares 100-series.<ref name=aw-20141216 /><ref name=nsf-20150812/><ref name=orbatkpr-20150812a />

====Antares 300====
While the 200 series uses the RD-181 by adapting the originally ordered 100 Series stages (KB Yuzhnoye/Yuzhmash, Zenit derived),<ref name=osc2014/> it requires under-throttling the RD-181 engines, which reduces performance. Thus, the 300 series will use a new first stage core designed for the full thrust and performance of the RD-181 engine.<ref name=nsf-20150812/>

===Second stage===
The second stage is an Orbital ATK [[Castor (rocket stage)|Castor 30]]-series [[solid-fuel rocket]], developed as a derivative of the Castor 120 solid motor used as [[Minotaur-C]]'s first stage.<ref>{{cite web |url=http://www.atk.com/products-services/castor-30-a-multi-use-motor |title=CASTOR 30-A Multi-use Motor |work=ATK.com |accessdate=July 10, 2014}}</ref> The first two flights of Antares used a Castor 30A, which was replaced by the enhanced Castor 30B for subsequent flights. The Castor 30B produces {{convert|293.4|kN|-1|abbr=on|adj=on}} average and {{convert|395.7|kN|-1|abbr=on|adj=on}} maximum thrust, and uses [[electromechanical]] [[Thrust vectoring|thrust vector]] control.<ref name="os201112a" /> For increased performance, the larger Castor 30XL is available<ref name="osc2014"/> and will be used on ISS resupply flights to allow Antares to carry the Enhanced Cygnus.<ref name="os201112a" /><ref name="Chris" /><ref name="nsf20130305" />

===Third stage===
Antares offers two optional third stages, the Bi-Propellant Third Stage (BTS) and a [[Star 48]]-based third stage. BTS is derived from Orbital Sciences' GEOStar [[spacecraft bus]] and uses [[nitrogen tetroxide]] and [[hydrazine]] for propellant; it is intended to precisely place payloads into their final orbits.<ref name="os201112b" /> The Star 48-based stage uses a [[Star 48|Star 48BV]] solid rocket motor and would be used for higher energy orbits.<ref name="os201112b" />

===Fairing===
The {{convert|3.9|m|sp=us|adj=on}} diameter, {{convert|9.9|m|sp=us|adj=on}} high [[Payload fairing|fairing]] is manufactured by [[Applied Aerospace Structures Corporation]] of [[Stockton, California]], which also builds other composite structures for the vehicle, including the fairing adaptor, stage 2 motor adaptor, stage 2 interstage, payload adaptor, and avionics cylinder.<ref name="aasc" />

===NASA Commercial Resupply Services 2 : Enhancements===
On January 14, 2016 NASA awarded three cargo contracts (CRS2) to ensure the critical science, research and technology demonstrations that are informing the agency’s journey to Mars are delivered to the International Space Station (ISS) from 2019 through 2024. Orbital ATK's Cygnus was one of these contracts.<ref name="nasa20160114">{{cite web |url=https://www.nasa.gov/press-release/nasa-awards-international-space-station-cargo-transport-contracts |title=NASA Awards International Space Station Cargo Transport Contracts |work=NASA |first1=Cheryl |last1=Warner |first2=Stephanie |last2=Schierholz |date=14 January 2016 |accessdate=6 July 2017}}</ref>

According to Mark Pieczynski, Orbital ATK Vice President, Flight Systems Group, “A further improved version [of Antares for CRS2 contract] is in development which will include: Stage 1 core updates including structural reinforcements and optimization to accommodate increased loads.

“(Also) certain refinements to the RD-181 engines and CASTOR 30XL motor; and Payload accommodations improvements including a ‘pop-top’ feature incorporated in the fairing to allow late Cygnus cargo load and optimized fairing adapter structure.”

Previously, it was understood that these planned upgrades from the Antares 230 series would create a vehicle known as the Antares 300 series.

However, when asked specifically about Antares 300 series development, Mr. Pieczynski stated that Orbital ATK has “not determined to call the upgrades, we are working on, a 300 series. This is still TBD.”<ref name="spaceflight20170203">{{cite web |url=https://www.nasaspaceflight.com/2017/02/orbital-atk-2017-cygnus-antares-enhancements-2019/ |title=Orbital ATK preps Cygnus flights; Antares enhancements on track for 2019 |work=NASA SpaceFlight |first=Chris |last=Gebhardt |date=3 February 2017 |accessdate=6 July 2017}}</ref>

==Configurations and numbering==
[[File:Castor 30 test fire.jpg|right|thumbnail|Test firing of the Castor 30 second stage]]
The first two test flights used a [[Castor (rocket stage)|Castor 30A]] second stage. All subsequent flights will use either a [[Castor (rocket stage)|Castor 30B]] or [[Castor (rocket stage)|Castor 30XL]]. The rocket's configuration is indicated by a three-digit number, the first number representing the first stage, the second the type of second stage, and the third the type of third stage.<ref name="Chris" />

{| class="wikitable" style="margin: 1em auto 1em auto;"
|-
!rowspan=2|Number
!First digit
!Second digit
!Third digit
|-
!(First stage)
!(Second stage)
!(Third stage)
|-
!0
|{{n/a}}
|{{n/a}}
|No third stage
|-
!1
|Block 1 first stage (2 × [[NK-33#Antares|AJ26-62]])
|[[Castor (rocket stage)|Castor 30A]] N/A after Block 1<ref name=osc2014/>
|[[Bipropellant Third Stage|BTS]] (3 × [[IHI Corporation|IHI]] [[BT-4 (rocket engine)|BT-4]])
|-
!2
|Block 1 first stage (Adapted to RD-181) (2 × [[RD-181]])<ref name=osc2014/>
|[[Castor (rocket stage)|Castor 30B]]
|[[Star 48|Star 48BV]]
|-
!3
|Block 2 first stage (2 × RD-181)<ref name=nsf-20150812 />
|[[Castor (rocket stage)|Castor 30XL]]
|{{n/a}}
|}

==Launch history==

===Inaugural flight===
{{main|Antares A-ONE}}
Originally scheduled for 2012, the first Antares launch, designated ''A-ONE''<ref name="NSF-AONE" /> was conducted on April 21, 2013,<ref name="sfnow20130421" /> carrying the [[Antares A-ONE#Payloads|Cygnus Mass Simulator]] (a [[boilerplate (spaceflight)|boilerplate]] [[Cygnus (spacecraft)|Cygnus spacecraft]]) and four [[CubeSat]]s contracted by [[Spaceflight Incorporated]]: [[Dove 1]] for [[Planet Labs|Cosmogia Incorporated]] (now Planet Labs) and three [[PhoneSat]] satellites – [[Alexander (satellite)|Alexander]],<ref name="krebs-phonev2" /> [[Graham (satellite)|Graham]] and [[Bell (satellite)|Bell]] for NASA.<ref name="krebs-phonev1" />

Prior to the launch, a 27-second test firing of the rocket's AJ26 engines was conducted successfully on February 22, 2013, following an attempt on February 13 which was abandoned before ignition.<ref name="Hotsuccess" />

''A-ONE'' used the Antares 110 configuration, with a [[Castor 30A]] second stage and no third stage. The launch took place from [[Mid-Atlantic Regional Spaceport Launch Pad 0|Pad 0A]] of the [[Mid-Atlantic Regional Spaceport]] on [[Wallops Island]], [[Virginia]]. LP-0A was a former [[Conestoga (rocket)|Conestoga]] launch complex which had only been used once before, in 1995, for the Conestoga's only orbital launch attempt.<ref name="NSF-launch" /> Antares became the largest — and first — liquid-fuelled rocket to fly from Wallops Island, as well as the largest rocket launched by Orbital Sciences.<ref name="NSF-AONE" />

The first attempt to launch the rocket, on April 17, 2013, was [[wikt:scrub#Verb|scrubbed]] after an umbilical detached from the rocket's second stage, and a second attempt on April 20 was scrubbed due to high altitude winds.<ref name="wapo20130421" /> At the third attempt on April 21, the rocket lifted off at the beginning of its launch window. The launch window for all three attempts was three hours beginning at 21:00 [[Coordinated Universal Time|UTC]] (17:00 [[Eastern Time Zone|EDT]]), shortening to two hours at the start of the terminal count, and ten minutes later{{clarify|date=September 2013}} in the count.<ref name="NSF-launch" /><ref name="bbc20130421" />

[[File:Antares Fails to Reach Orbit with Cygnus CRS-3 after Rocket Explodes.webm|thumb|left|Video of failed Cygnus CRS Orb-3 mission]]
[[File:Aftermath of Antares Orb-3 explosion at Pad 0A (20141029a).jpg|thumb|150px|right|Pad 0A after the incident]]

===October 2014 incident===
On October 28, 2014, the attempted launch of an Antares carrying a [[Cygnus (spacecraft)|Cygnus]] cargo spacecraft on the [[Cygnus CRS Orb-3|Orb-3]] resupply mission failed catastrophically six seconds after liftoff from [[Mid-Atlantic Regional Spaceport]] at [[Wallops Flight Facility]], [[Virginia]].<ref name="sfnantares10-26-2014" /> An explosion occurred in the thrust section just as the vehicle cleared the tower, and it fell back down onto the pad. The Range Safety officer sent the destruct command just before impact.<ref name="latimes20141028"/><ref name="orb3_termination" /> There were no injuries.<ref name=cargolost /> Orbital Sciences reported that [[Mid-Atlantic Regional Spaceport Launch Pad 0|Launch Pad 0A]] "escaped significant damage,"<ref>{{cite press release |title=ISS Commercial Resupply Services Mission (Orb-3) |url=https://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/default.aspx |date=October 30, 2014 |publisher=Orbital Sciences Corporation |quote="no evidence of significant damage" |archiveurl=https://www.webcitation.org/6Tj4mG4Wp?url=https://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/default.aspx |archivedate=October 31, 2014 |deadurl=yes |df=mdy}}</ref> though initial estimates for repairs were in the $20 million range.<ref>{{cite news |url=http://spacenews.com/42620virginia-may-seek-federal-funds-for-wallops-spaceport-repairs/ |title=Virginia May Seek Federal Funds for Wallops Spaceport Repairs |work=[[SpaceNews]] |first=Jeff |last=Foust |date=November 21, 2014 |accessdate=November 5, 2017}}</ref> Orbital Sciences formed an anomaly investigation board to investigate the cause of the incident. They traced it to a failure of the first stage LOX turbopump, but could not find a specific cause. However, the refurbished NK-33 engines, originally manufactured over 40 years earlier and stored for decades, were suspected as having leaks, corrosion, or manufacturing defects that had not been detected.<ref>{{cite web |url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |title=ISS Commercial Resupply Services Mission (Orb-3) |publisher=Orbital Sciences Corporation |archivedate=October 29, 2014 |archiveurl=https://www.webcitation.org/6Tg48UMjO?url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |deadurl=no |accessdate=October 28, 2014 |df=mdy}}</ref> On October 6, 2015, almost one year after the accident, Pad 0A was restored to use. Total repair costs were about $15 million.<ref>{{cite news |url=https://spaceflightnow.com/2015/10/06/workers-complete-15-million-in-repairs-to-antares-launch-pad/ |title=Workers complete $15 million in repairs to Antares launch pad |work=Spaceflight Now |first=Stephen |last=Clark |date=October 6, 2015 |accessdate=November 5, 2017}}</ref>

Following the failure, Orbital sought to purchase launch services for its Cygnus spacecraft in order to satisfy its cargo contract with NASA,<ref name=sfi-20141124 /> and on December 9, 2014, Orbital announced that at least one, and possibly two, Cygnus flights would be launched on [[Atlas V]] rockets from [[Cape Canaveral Air Force Station]].<ref name="Atlas_V">{{cite news |url=https://www.space.com/27962-cygnus-cargo-spacecraft-new-rocket.html |title=Private Cargo Spacecraft Gets New Rocket Ride After Accident |work=Space.com |first=Miriam |last=Kramer |date=December 9, 2014 |accessdate=November 5, 2017}}</ref> As it happened, [[Cygnus CRS OA-4|Cygnus OA-4]] and [[Cygnus CRS OA-6|OA-6]] were launched with an Atlas V and the Antares 230 performed its maiden flight with [[Cygnus CRS OA-5|Cygnus OA-5]] in October 2016. One further mission was launched aboard an Atlas in April 2017 ([[Cygnus CRS OA-7|OA-7]]), fulfilling Orbital's contractual obligations towards NASA. It will be followed by the Antares 230 in regular service with [[Cygnus CRS OA-8E|OA-8E]] in November 2017 and further missions from their extended contract.

==List of missions==
''List includes only currently manifested missions. All missions are launched from [[Mid-Atlantic Regional Spaceport]] [[Mid-Atlantic Regional Spaceport Launch Pad 0|Launch Pad 0A]].''

{| class="wikitable" style="margin: 1em auto 1em auto; font-size:95%;" width="98%"
|+Antares launch history
! #
! Launch date, time ([[UTC]])
! Mission
! Payload
! Cygnus version
! Rocket version
! Ref.
! Outcome

|-
| rowspan=2 style="text-align:center;" | 1
| style="text-align:left;" nowrap="nowrap" | April 21, 2013. 21:00
| nowrap="nowrap" | [[Antares A-ONE]]
| nowrap="nowrap" | {{Unbulleted list| [[Cygnus Mass Simulator]] | [[Dove (satellite)|Dove 1]] [[Alexander (satellite)|Alexander]] [[Graham (satellite)|Graham]] [[Bell (satellite)|Bell]] }}
| Standard (mass simulator)
| nowrap="nowrap" | Antares 110
| <ref name="nasapr20130421" /><ref name="orbital201212" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | Antares test flight, using a Castor 30A second stage and no third stage.

|-
| rowspan=2 style="text-align:center;" | 2
| style="text-align:left;" nowrap="nowrap" | September 18, 2013. 14:58
| nowrap="nowrap" | [[Cygnus Orb-D1|Orb-D1]]
| nowrap="nowrap" | ''[[G. David Low]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 110
| <ref name="sfnow20130506" /><ref name="colspace20131209" /><ref name="spaceflightnow" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | Orbital Sciences COTS demonstration flight. First Cygnus mission, first mission to rendezvous with ISS, first mission to berth with ISS, second launch of Antares. The rendezvous between the new Cygnus cargo freighter and the International Space Station was delayed due to a computer data link problem,<ref name="wapo20130922" /> but the issue was resolved and berthing followed shortly thereafter.<ref name="nasasf20130928" />

|-
| rowspan=2 style="text-align:center;" | 3
| style="text-align:left;" nowrap="nowrap" | January 9, 2014. 18:07
| nowrap="nowrap" | [[Cygnus CRS Orb-1|CRS Orb-1]]
| nowrap="nowrap" | ''[[C. Gordon Fullerton]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 120
| <ref name="Antareshome" /><ref name="Chris" /><ref name="colspace20131209" /><ref name="spaceflightnow" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | First Commercial Resupply Service (CRS) mission for Cygnus, and first Antares launch using the Castor 30B upper stage.

|-
| rowspan=2 style="text-align:center;" | 4
| style="text-align:left;" nowrap="nowrap" | July 13, 2014. 16:52
| [[Cygnus CRS Orb-2|CRS Orb-2]]
| ''[[Janice Voss]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 120
| <ref name="Chris" /><ref name="spaceflightnow" /><ref name="orb2_orbital" />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | Spacecraft carried {{convert|1664|kg|lb|abbr=on}} of supplies for the ISS, including research equipment, crew provisions, hardware, and science experiments.

|-
| rowspan=2 style="text-align:center;" | 5
| style="text-align:left;" nowrap="nowrap" | October 28, 2014. 22:22
| [[Cygnus CRS Orb-3|CRS Orb-3]]
| ''[[Deke Slayton]]'' Cygnus
| Standard
| nowrap="nowrap" | Antares 130
| <ref name="Chris" /><ref name="nasa20141019">{{cite web |url=http://www.nasa.gov/mission_pages/station/structure/launch/orbital.html |title=Orbital Sciences Commercial Resupply Launch |publisher=NASA |accessdate=October 19, 2014 |archiveurl=https://web.archive.org/web/20141019220903/http://www.nasa.gov/mission_pages/station/structure/launch/orbital.html |archivedate=October 19, 2014 |deadurl=no}}</ref>
| rowspan=2 {{Failure}}
|-
| colspan=6 style="background-color:#e4dfdf;" |LOX turbopump failure T+6 seconds. Rocket fell back onto the pad and exploded.<ref>https://www.nasa.gov/sites/default/files/atoms/files/orb3_irt_execsumm_0.pdf</ref><ref name="sfnantares10-26-2014">{{cite web|url=http://spaceflightnow.com/2014/10/26/live-coverage-antares-rocket-set-for-launch-monday-from-virginia/|title=Antares explodes moments after launch|work=Spaceflight Now|date=October 28, 2014|accessdate=October 28, 2014}}</ref><ref name=cargolost>{{cite news|last1=Wall|first1=Mike|title=Private Orbital Sciences Rocket Explodes During Launch, NASA Cargo Lost|url=http://www.space.com/27576-private-orbital-sciences-rocket-explosion.html|website=Space.com|publisher=Purch|accessdate=October 28, 2014|date=October 28, 2014}}</ref> First Antares launch to use Castor 30XL upper stage. In addition to supplies for the International Space Station, payload included a [[Planetary Resources]] [[Arkyd-3]] satellite and a NASA JPL/UT-Austin CubeSat mission named RACE.<ref name=psbj20141016>{{cite news |url=http://www.bizjournals.com/seattle/news/2014/10/16/first-step-toward-asteroid-mining-planetary.html?page=all |title=First step toward asteroid mining: Planetary Resources set to launch test satellite |work=Puget Sound Business Journal |first=Steve |last=Wilhelm |date=October 16, 2014 |accessdate=October 19, 2014}}</ref><ref name="RACE20141">{{cite web |url=http://cubesat.jpl.nasa.gov/projects/race/mission.html |title=RACE Mission |publisher=NASA |accessdate=October 28, 2014 |archiveurl=https://web.archive.org/web/20141019220903/http://cubesat.jpl.nasa.gov/projects/race/mission.html |archivedate=October 19, 2014 |deadurl=no}}</ref><ref name="RACE20142">{{cite web |url=http://www.ae.utexas.edu/news/features/race-space-week |title=RACE Satellite Launching to ISS |publisher=University of Texas at Austin |accessdate=October 28, 2014 |archiveurl=https://web.archive.org/web/20141019220903/http://www.ae.utexas.edu/news/features/race-space-week |archivedate=October 19, 2014 |deadurl=no}}</ref>
|-
| rowspan=2 style="text-align:center;" | 6
| style="text-align:left;" nowrap="nowrap" | October 17, 2016. 23:45
| [[Cygnus CRS OA-5|CRS OA-5]]
| ''[[Alan G. Poindexter]]'' Cygnus
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=orbatkpr-20150812a /><ref name="Chris" /><ref name="Orbital_manifest" /><ref name=rtf>{{cite web|url=http://www.orbital.com/NewsInfo/release.asp?prid=1921|title=Orbital Announces Go-Forward Plan for NASA's Commercial Resupply Services Program and the Company's Antares Launch Vehicle|website=orbital.com|publisher=Orbital Sciences Corporation|date=November 5, 2014|accessdate=November 5, 2014}}</ref><ref name=sfn_ls>{{cite web |url=http://spaceflightnow.com/launch-schedule/ |title=Spaceflight Now — Launch schedule |work=Spaceflight Now |last=Clark |first=Stephen |date=April 25, 2017 |accessdate=April 26, 2017}}</ref><ref name=sfn_ls2>{{cite web |url=https://spaceflightnow.com/2016/10/17/oa-5-mission-status-center/ |title=Spaceflight Now — Live coverage: Antares rocket returns to flight Monday |work=Spaceflight Now |last=Clark |first=Stephen |date=October 17, 2016 |accessdate=October 17, 2016}}</ref>
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" | First launch of Enhanced Cygnus on Orbital's new Antares 230.

|-
| rowspan=2 style="text-align:center;" | 7
| style="text-align:left;" nowrap="nowrap" |November 12, 2017. 12:19:51
| [[Cygnus CRS OA-8E|CRS OA-8E]]
| ''[[Gene Cernan]]'' Cygnus
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=sfn_ls /><ref name=iss-calendar />
| rowspan=2 {{Success}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|-
| rowspan=2 style="text-align:center;" | 8
| style="text-align:left;" nowrap="nowrap" | March 2018 
| [[Cygnus CRS OA-9E|CRS OA-9E]]
|
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=iss-calendar />
| rowspan=2 {{Planned}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|-
| rowspan=2 style="text-align:center;" | 9
| style="text-align:left;" nowrap="nowrap" | October 2018 
| [[Cygnus CRS OA-10E|CRS OA-10E]]
|
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=iss-calendar />
| rowspan=2 {{Planned}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|-
| rowspan=2 style="text-align:center;" | 10
| style="text-align:left;" nowrap="nowrap" | February 2019 
| [[Cygnus CRS OA-11E|CRS OA-11E]]
|
| Enhanced
| nowrap="nowrap" | Antares 230
| <ref name=iss-calendar>{{cite web |url=http://spaceflight101.com/iss/iss-calendar/ |title=International Space Station Calendar |work=Spaceflight 101 |date=April 17, 2017 |access-date=April 26, 2017}}</ref>
| rowspan=2 {{Planned}}
|-
| colspan=6 style="background-color:#e4dfdf;" |

|}

Note: [[Cygnus CRS OA-4]], the first Enhanced Cygnus mission, and [[Cygnus CRS OA-6|OA-6]] were propelled by [[Atlas V]] 401 launch vehicles while the new Antares 230 was in its final stages of development. [[Cygnus CRS OA-7]] was also switched to an [[Atlas V]] and launched on April 18, 2017.

==Launch sequence==
The following table shows a typical launch sequence of Antares-100 series rockets, such as for launching a [[Cygnus (spacecraft)|Cygnus]] spacecraft on a [[Commercial Orbital Transportation Services|cargo resupply mission]] to the International Space Station.<ref name=presskit>{{cite web |url=http://www.nasa.gov/sites/default/files/files/Orb2_PRESS_KIT.pdf |title=Orbital-2 Mission to the International Space Station Media Press Kit |publisher=NASA |date=July 2014 |accessdate=July 13, 2014}}</ref>

{| class="wikitable"
|-
! Mission time !! Event !! Altitude
|-
| T− 03:50:00 || Launch management call to stations ||
|-
| T− 03:05:00 || Poll to initiate liquid oxygen loading system chilldown ||
|-
| T− 01:30:00 || Poll for readiness to initiate propellant loading ||
|-
| T− 00:15:00 || [[Cygnus (spacecraft)|Cygnus]]/payload switched to internal power ||
|-
| T− 00:12:00 || Poll for final countdown and {{abbr|MES|Main Engine System}} medium flow chilldown ||
|-
| T− 00:11:00 || Transporter-Erector-Launcher (TEL) armed for rapid retract ||
|-
| T− 00:05:00 || Antares avionics switched to internal power ||
|-
| T− 00:03:00 || Auto-sequence start (terminal count) ||
|-
| T− 00:02:00 || Pressurize propellant tanks ||
|-
| T− 00:00:00 || Main engine ignition ||
|-
| T+ 00:00:02.1 || Liftoff || 0
|-
| T+ 00:03:55 || Main engine cut-off (MECO) || {{convert|102|km|0|abbr=on}}
|-
| T+ 00:04:01 || Stage one separation || {{convert|108|km|0|abbr=on}}
|-
| T+ 00:05:31 || Fairing separation || {{convert|168|km|0|abbr=on}}
|-
| T+ 00:05:36 || Interstage separation || {{convert|170|km|0|abbr=on}}
|-
| T+ 00:05:40 || Stage two ignition || {{convert|171|km|0|abbr=on}}
|-
| T+ 00:07:57 || Stage two burnout || {{convert|202|km|0|abbr=on}}
|-
| T+ 00:09:57 || Payload separation || {{convert|201|km|0|abbr=on}}
|}

==See also==
{{Portal|Spaceflight}}
* [[Comparison of orbital launchers families]]
* [[Minotaur-C]]
* [[Falcon 9]]

==References==
{{Reflist |30em |refs=
<ref name=slr20110514>{{cite web |url=http://www.spacelaunchreport.com/taurus2.html |title=Taurus 2 |work=Space Launch Report |first=Ed |last=Kyle |date=May 14, 2011}}</ref>

<ref name=os201112b>{{cite web |url=http://www.orbital.com/NewsInfo/Publications/Antares_fact.pdf |title=Antares Medium-class Launch Vehicle: Fact Sheet |format=PDF |publisher=Orbital Sciences Corporation |year=2013 |accessdate=April 25, 2013 |archiveurl=https://web.archive.org/web/20130603115601/http://www.orbital.com/NewsInfo/Publications/Antares_fact.pdf |archivedate=June 3, 2013}}</ref>

<ref name="os20140806">{{cite press release |url=http://www.orbital.com/LaunchSystems/SpaceLaunchVehicles/Antares |title=Antares |publisher=Orbital Sciences Corporation|accessdate=August 5, 2014}}</ref>

<ref name="sf101-antares100">{{cite web|title=Antares (100 Series)|url=http://spaceflight101.com/spacerockets/antares-100-series/|website=SpaceFlight101|accessdate=May 5, 2016}}</ref>

<ref name="sf101-antares200">{{Cite web|url=http://spaceflight101.com/spacerockets/antares-200-series/|title=Antares 200 Series – Rockets|website=spaceflight101.com|access-date=November 7, 2016}}</ref>

<ref name="nasapr20130421">{{cite press release |url=http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-114_Antares_launches.html |title=NASA Partner Orbital Sciences Test Launches Antares Rocket |publisher=NASA |first=Trent J. |last=Perrotto |date=April 21, 2013 |accessdate=April 25, 2013}}</ref>

<ref name="Antareshome">{{Cite web |url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-1/ |title=ISS Commercial Resupply Services Mission (Orb-1) |publisher=Orbital Sciences Corporation |accessdate=January 8, 2014}}</ref>

<ref name="os201112a">{{cite web |url=http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdf |title=Antares Medium-Class Launch Vehicle: Brochure |format=PDF |publisher=Orbital Sciences Corporation |year=2013 |accessdate=April 25, 2012|archiveurl=https://web.archive.org/web/20140209070336/http://www.orbital.com/NewsInfo/Publications/Antares_Brochure.pdf|archivedate=February 9, 2014 }}</ref>

<ref name="NSF-launch">{{cite news |url=http://www.nasaspaceflight.com/2013/04/orbital-antares-debut-launch-attempt/ |title=Antares conducts a flawless maiden launch |work=NASA Spaceflight |first=William |last=Graham |date=April 21, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="avweek20080225">{{cite journal |title=none|journal=Aviation Week and Space Technology |page=22 |date=February 25, 2008}}</ref>

<ref name="orbital20111212">{{cite press release |url=http://www.orbital.com/NewsInfo/release.asp?prid=798 |title=Orbital Selects "Antares" as Permanent Name for New Rocket Created by the Taurus II R&D Program |publisher=Orbital Sciences Corporation |first=Barron |last=Beneski |date=December 12, 2011}}</ref>

<ref name="Bergen">{{cite news |title=none|work=Space News |first=Chris |last=Bergin |page=12 |date=February 25, 2008}}</ref>

<ref name="fglobal20120430">{{cite news |url=http://www.flightglobal.com/news/articles/orbital-sciences-development-costs-increase-371291/ |title=Orbital Sciences development costs increase |work=Flight International ''via'' Flightglobal.com |first=Zach |last=Rosenberg |date=April 30, 2012}}</ref>

<ref name="yesver20080609">{{cite press release |url=http://www.yesvirginia.org/about_us/NewsArticle.aspx?newsid=945 |title=Governor Kaine announces 125 new jobs for Virginia |publisher=Commonwealth of Virginia ''via'' YesVirginia.org |first=Gordon |last=Hickey |date=June 9, 2008}}</ref>

<ref name="spaceports20080613">{{cite web|url=http://spaceports.blogspot.com/2008/06/taurus-2-launch-pad-to-be-ready-in-18.html |title=Taurus-2 Launch Pad to be Ready in 18-Months at Wallops Island Spaceport |work=Spaceports |publisher=Blogspot.com |first=Jack |last=Kennedy |date=June 13, 2008}}</ref>

<ref name="hampton20080220">{{cite news |url=http://hamptonroads.com/2008/02/wallops-big-role-firms-nasa-contract |title=Wallops up for big role with firm's NASA contract |work=The Virginian-Pilot ''via'' HamptonRoads.com |first=Jon W. |last=Glass |date=February 20, 2008}}</ref>

<ref name="Hotsuccess">{{cite news |url=http://www.nasaspaceflight.com/2013/02/hot-fire-success-orbitals-antares/ |title=Hot fire success for Orbital's Antares |work=NASA Spaceflight |first=Chris |last=Bergin |date=February 22, 2013 |accessdate=February 23, 2013}}</ref>

<ref name="orbital20091210">{{cite press release |url=http://www.orbital.com/NewsInfo/release.asp?prid=712 |title=Second Stage Rocket Motor Of Orbital's Taurus II Launcher Successfully Ground Tested |publisher=Orbital Sciences Corporation |first=Barron |last=Beneski |date=December 10, 2009}}</ref>

<ref name=spaceflight-now-20100315>{{cite news |url=http://spaceflightnow.com/news/n1003/15nk33/ |title=Aerojet confirms Russian engine is ready for duty |work=Spaceflight Now |first=Stephen |last=Clark |date=March 15, 2010 |accessdate=March 18, 2010 |archiveurl=https://web.archive.org/web/20100322200821/http://www.spaceflightnow.com/news/n1003/15nk33/ |archivedate=March 22, 2010 |deadurl=no}}</ref>

<ref name=ug12>{{cite web |url=http://www.orbital.com/NewsInfo/Publications/Antares_Guide.pdf |title=Antares User's Guide, Rev. 1.2 |format=PDF |publisher=Orbital Sciences Corporation |date=December 2009}}</ref>

<ref name="aasc">{{cite web |url=https://www.aascworld.com/Antares/service--1211796061/program.html |title=Antares Launch Vehicle |publisher=Applied Aerospace Structures Corporation |accessdate=April 26, 2014}}</ref>

<ref name="Chris">{{cite news |url=http://www.nasaspaceflight.com/2012/02/orbital-upbeat-ahead-of-antares-debut/ |title=Space industry giants Orbital upbeat ahead of Antares debut |work=NASA Spaceflight |first=Chris |last=Bergin |date=February 22, 2012 |accessdate=March 29, 2012}}</ref>

<ref name="nsf20130305">{{cite news |url=http://www.nasaspaceflight.com/2013/03/castor-30xl-prepares-static-fire-antares-boost/ |title=CASTOR 30XL prepares for static fire ahead of providing Antares boost |work=NASA Spaceflight |first=Chris |last=Bergin |accessdate=March 7, 2013 |date=March 5, 2013}}</ref>

<ref name="NSF-AONE">{{cite news |url=http://www.nasaspaceflight.com/2013/03/orbitals-antares-debut-a-one-mission-april/ |title=Stars align for Orbital's Antares – A-One debut set for mid-April |work=NASA Spaceflight |first=Chris |last=Bergin |date=March 17, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="sfnow20130421">{{cite news |url=http://www.spaceflightnow.com/antares/demo/130421launch/ |title=Antares test launch paves new highway to space station |work=Spaceflight Now |first=Stephen |last=Clark |date=April 21, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="krebs-phonev2">{{cite web |url=http://space.skyrocket.de/doc_sdat/phonesat-v2.htm |title=PhoneSat v2 |work=Gunter's Space Page |first=Gunter |last=Krebs |accessdate=April 22, 2013}}</ref>

<ref name="krebs-phonev1">{{cite web |url=http://space.skyrocket.de/doc_sdat/phonesat-v1.htm |title=PhoneSat v1 |work=Gunter's Space Page |first=Gunter |last=Krebs |accessdate=April 22, 2013}}</ref>

<ref name="wapo20130421">{{cite news |url=https://www.washingtonpost.com/local/wind-postpones-rocket-launch-at-wallops-flight-facility/2013/04/20/8d2c9f6c-aa15-11e2-a8e2-5b98cb59187f_story.html |title=Wind postpones rocket launch at Wallops Flight Facility |newspaper=[[The Washington Post]] |last=Weil |first=Martin |date=April 21, 2013}}</ref>

<ref name="bbc20130421">{{Cite news |url=http://www.bbc.co.uk/news/science-environment-22193330 |title=Orbital's Antares rocket makes test flight |work=BBC News |first=Jonathan |last=Amos |date=April 21, 2013 |accessdate=April 22, 2013}}</ref>

<ref name="orbital201212">{{cite web |url=http://www.orbital.com/Antares-Cygnus/ |title=Antares Cold Flow Testing Begins and Antares A-ONE Gets All Dressed Up |publisher=Orbital Sciences Corporation |date=December 2012 |accessdate=March 5, 2013|archiveurl=https://web.archive.org/web/20130306151415/http://www.orbital.com/Antares-Cygnus/ |archivedate=March 6, 2013}}</ref>

<ref name="wapo20130922">{{cite news |url=https://www.washingtonpost.com/national/health-science/computer-mishap-delays-space-station-supply-ship-cygnus/2013/09/22/69145610-23a0-11e3-b75d-5b7f66349852_story.html |title=Computer mishap delays space station supply ship Cygnus |work=[[The Washington Post]] |first=Marcia |last=Dunn |date=September 22, 2013 |accessdate=September 22, 2013}}</ref>

<ref name="nasasf20130928">{{cite news |url=http://www.nasaspaceflight.com/2013/09/cygnus-second-attempt-berth-iss/ |title=Orbital’s Cygnus successfully berthed on the ISS |work=NASA Spaceflight |first=Chris |last=Bergin |date=September 28, 2013 |accessdate=October 8, 2013}}</ref>

<ref name="sfnow20130506">{{cite news |url=http://spaceflightnow.com/antares/cots1/130506schedule/ |title=First flight of Cygnus cargo craft delayed to September |work=Spaceflight Now |first=Stephen |last=Clark |date=May 6, 2013 |accessdate=August 7, 2013}}</ref>

<ref name="colspace20131209">{{cite news |url=http://www.collectspace.com/news/news-120913a.html |title=Orbital names next space station freighter for late pilot-astronaut |work=CollectSpace.com |first=Robert Z. |last=Pearlman |date=December 9, 2013 |accessdate=December 9, 2013}}</ref>

<ref name="spaceflightnow">{{cite web |url=http://spaceflightnow.com/tracking/index.html |title=Worldwide launch schedule |work=Spaceflight Now |accessdate=August 9, 2013 |archiveurl=https://web.archive.org/web/20130811033415/http://www.spaceflightnow.com/tracking/index.html |archivedate=August 11, 2013 |deadurl=yes}}</ref>

<ref name="Orbital_manifest">{{cite web |url=http://www.orbital.com/Antares-Cygnus/Missions/ |title=Launch Manifest |publisher=Orbital Sciences Corporation |accessdate=December 8, 2013 |archiveurl=https://web.archive.org/web/20131211023414/http://www.orbital.com/Antares-Cygnus/Missions/ |archivedate=December 11, 2013 |deadurl=yes}}</ref>

<ref name=orb2_orbital>{{cite web |url=https://www.orbital.com/NewsInfo/MissionUpdates/Orb-2/ |title=ISS Commercial Resupply Services Mission (Orb-2) |publisher=Orbital Sciences Corporation |year=2014 |accessdate=July 13, 2014 |archiveurl=https://web.archive.org/web/20140407074542/http://www.orbital.com/NewsInfo/MissionUpdates/Orb-2/ |archivedate=April 7, 2014}}</ref>

<ref name=orb3_termination>{{cite web |url=http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |title=ISS Commercial Resupply Services Mission (Orb-3) |publisher=Orbital Sciences Corporation |year=2014 |accessdate=October 31, 2014 |archiveurl=https://web.archive.org/web/20141031051957/http://www.orbital.com/NewsInfo/MissionUpdates/Orb-3/ |archivedate=October 31, 2014}}</ref>

<ref name=nsf-20150812>{{cite news |url=http://www.nasaspaceflight.com/2015/08/orb-4-cygnus-set-atlas-v-ride-ahead-antares-return/ |title=Cygnus set for December Atlas V ride ahead of Antares return |website=NASA Spaceflight |first=Chris |last=Bergin |quote=“LSP Vehicle Systems Engineering, Propulsion Engineering, Stress, Avionics and SMA (Safety and Mission Assurance) participated in the Antares Stage 1 CDR for the modifications necessary to integrate the RD-181 engine at both the 230 and 330 thrust levels.” |date=August 7, 2015 |accessdate=August 12, 2015}}</ref>

<ref name=orbatkpr-20150812a>{{cite web |url=http://www.orbitalatk.com/news-room/feature-stories/CRSUpdate/default.aspx |title=Orbital ATK Team on Track for Fall 2015 Cygnus Mission and Antares Return to Flight in 2016 |publisher=[[Orbital ATK]] |date=August 12, 2015 |accessdate=August 12, 2015}}</ref>

<ref name=sfi-20141124>{{cite news |title=Orbital’s Cygnus – on a SpaceX Falcon 9? |url=http://www.spaceflightinsider.com/missions/commercial/orbitals-cygnus-spacex-falcon-9/ |accessdate=November 28, 2014 |work=spaceflightinsider.com |date=November 24, 2014 |quote=''Orbital has announced that it is planning to use another engine on Antares and that it will likely not use any more of the 40-year-old AJ-26 engines on the rocket’s next flight – which Orbital hopes to conduct in 2016.'' }}</ref>

<ref name=tass-20141031>{{cite news |url=http://en.itar-tass.com/non-political/757591 |title=Orbital Sciences likely to choose Russian engine for new Antares rocket |work=TASS |date=October 31, 2014 |accessdate=October 31, 2014}}</ref>

<ref name=sfn-20150122>{{Cite web |url = http://spaceflightnow.com/2015/01/22/orbital-sciences-signs-contract-for-new-antares-engines/ |title = Orbital Sciences signs contract for new Antares engines |date=January 22, 2015 |accessdate=June 27, 2017 |website = Spaceflight Now}}</ref>

<ref name=aw-20141216>{{cite news |last1=Morring |first1=Frank, Jr. |title=Antares Upgrade Will Use RD-181s In Direct Buy From Energomash |url=http://aviationweek.com/space/antares-upgrade-will-use-rd-181s-direct-buy-energomash |accessdate=December 28, 2014 |work=Aviation Week |date=December 16, 2014 }}</ref>

}}

==External links==
{{Commons category|Antares (rocket)}}
* {{Official website|http://www.orbitalatk.com/products-services/antares}}

{{Cygnus spaceflights}}
{{Expendable launch systems}}
{{US launch systems}}

{{Use American English|date=January 2014}}

[[Category:Antares (rocket family)| ]]
[[Category:Articles containing video clips]]
[[Category:Vehicles introduced in 2013]]

WAC Corporal

2017-10-21T22:10:53Z

Blastr42: /* Name */

__NOTOC__
[[File:Frank_Malina_with_WAC_Corporal_rocket_at_White_Sands.jpg|right|thumb|250px|[[Jet Propulsion Laboratory|JPL]] director [[Frank Malina]] with a WAC Corporal rocket (minus the solid-fuel boosters).]]

The '''WAC''' or '''WAC Corporal''' was the first [[sounding rocket]] developed in the [[United States]].<ref>
{{cite web | url = https://history.nasa.gov/SP-4401/ch2.htm | title = NASA Sounding Rockets, 1958-1968: A Historical Summary, Ch. 2 | publisher = NASA | year = 1971}}</ref> Begun as a spinoff of the [[MGM-5 Corporal|Corporal]] program, the WAC was a "little sister" to the larger Corporal. It was designed and built jointly by the [[Douglas Aircraft Company]] and the [[Guggenheim Aeronautical Laboratory]].<ref name="Boeing">
{{cite web | url = http://www.boeing.com/history/mdc/wac.html | title = WAC Corporal Missile | publisher = Boeing}}</ref>

The WAC Corporal was a [[hypergolic]] liquid-fuel rocket. Fuming [[nitric acid]] was the [[oxidizing agent|oxidizer]] and a mixture of [[aniline]] and [[furfuryl alcohol]] (with the later addition of [[hydrazine]]) was the [[rocket fuel|fuel]]. It was launched by a solid fuel [[Tiny Tim (rocket)|Tiny Tim]] booster.

The first WAC Corporal dummy round was launched on September 16, 1945 from [[White Sands Missile Range]] near [[Las Cruces, New Mexico]]. After a White Sands V-2 rocket had reached {{convert|69|mi|order=flip}} on May 10, a White Sands WAC Corporal reached {{convert|80|km}} on May 22, 1946 — the first U.S.-designed rocket to reach the edge of space (under the U.S. definition of space at the time). On February 24, 1949, a [[Bumper (rocket)|Bumper]] (a German [[V-2 rocket]] acting as first stage) bearing a WAC Corporal at White Sands accelerated to {{convert|5150|mph|order=flip}} to become the first flight of more than five times the speed of sound.<ref name=Winter>{{Citation
| last1 = Canan| first1 = James W
| title = A brief history of hypersonics
| magazine = Aerospace America | page=30
| date = November 2007 }}</ref>

Scientists were later surprised when almost a year after the launch, tail fragments of the WAC Corporal rocket that reached {{convert|5150|mph|order=flip}} and an altitude of over {{convert|250|mi|order=flip}}, were found and identified in the New Mexico desert near the launch site.<ref>[https://news.google.com/newspapers?id=KZIzAAAAIBAJ&sjid=H8QDAAAAIBAJ&dq=white%20sands&pg=2549%2C2699124 "Fragment of Rocket Sets New Mystery"], ''Melbourne, Australia - The Age newspaper'', Jan 31, 1950</ref>

A few WAC Corporals survive in museums, including one at the [[National Air and Space Museum]] and another in the White Sands Missile Range Museum.

== Name ==
The early U.S. rocket programs were named for [[enlisted rank]]s in the [[United States Army]]: Recruit, [[Private (missile)|Private]], [[MGM-5 Corporal|Corporal]], and [[MGM-29 Sergeant|Sergeant]]. When, in the words of former [[Jet Propulsion Laboratory|JPL]] director [[William Hayward Pickering]], researchers "came along with this sounding rocket which really didn't fit the pattern" of "getting bigger as you went along", the rocket "was named after the [[Women's Army Corps|Women’s Army Corps]] (WAC)".<ref>{{cite web | url = http://www.ksc.nasa.gov/kscoralhistory/documents/bumpergroup.pdf | title = Bumper 8: 50th Anniversary of the First Launch on Cape Canaveral, Group Oral History, Kennedy Space Center, Held on July 24, 2000 | author = NASA | date = 2001 | page = 13}}</ref>{{#tag:ref|The expansion "without attitude control" sometimes given for ''WAC'' may, in light of Pickering‘s explanation, be dismissed as a [[backronym]], its best available attribution being to "some sources".<ref name="Boeing" />|group="nb"}}

== Specifications ==

=== Overall dimensions ===

* '''Diameter:''' {{convert|1|ft|cm|order=flip}}
* '''Total length:''' {{convert|24|ft|cm|order=flip}}

=== Tiny Tim booster ===

* '''Loaded weight:''' {{convert|759.2|lb|order=flip}}
* '''Propellant weight:''' {{convert|148.7|lb|order=flip}}
* '''Thrust:''' {{convert|50000|lbf|kN|order=flip|abbr=on}}
* '''Duration:''' 0.6 s
* '''Impulse:''' 133,000 N·s (30,000 lbf·s)

=== WAC Corporal sustainer ===

* '''Empty weight:''' {{convert|296.7|lb|order=flip}}
* '''Loaded weight:''' {{convert|690.7|lb|order=flip}}
* '''Thrust:''' {{convert|1500|lbf|kN|order=flip|abbr=on}}
* '''Duration:''' 47 s
* '''Impulse:''' 298,000 N·s (67,000 lbf·s)

== Notes ==
<references group="nb"/>

== References ==
{{Reflist}}
* Alway, Peter, ''Rockets of the World, Third Edition.'' Saturn Press: Ann Arbor, 1999.

== External links ==
* [http://www.astronautix.com/lvs/wac.htm Astronautix.com article]
* [http://www.designation-systems.net/dusrm/app1/rtv-g-1.html Article from Directory of U.S. Military Rockets and Missiles]
* [http://www.nasm.si.edu/exhibitions/gal114/SpaceRace/sec200/sec220.htm Article from National Air and Space Museum]
* [https://books.google.com/books?id=kiEDAAAAMBAJ&pg=PA66&dq=popular+science+1943+skin&hl=en&ei=lHbOTLzcJYH_nAeX97zUDw&sa=X&oi=book_result&ct=result&resnum=5&ved=0CDgQ6AEwBDgK#v=onepage&q&f=true '' "50 Miles Up This Summer" '', May 1946, Popular Science]

{{Rank rockets}}
{{USA missiles}}

[[Category:Sounding rockets of the United States]]
[[Category:Rocketry]]
[[Category:Douglas Aircraft Company]]