Talk:Space Launch System

Radiation hazard needs to be quantified

The following addition to the picture attached was deleted as "irrelevant" by the previous editor. However I can't fathom why someone would think a ~1 Sievert to and fro radiation exposure to crew would be deemed "irrelevant". The length of the chemical propelled MSL mission was approximately 8 months, 240 days, the graphics 180 day estimate is based on readings from this mission. It is relevant to the choice of the upper stage engines of the crewed Mars transfer vehicle if they are propelled by slow chemical engines or something comparatively exotic that could do it in 180 days or less.

[[File:PIA17601-Comparisons-RadiationExposure-MarsTrip-20131209.png|thumb|right|Comparison of Radiation Doses from cosmic rays and the solar wind in milliSieverts detected on the trip from Earth to Mars by the RAD on the MSL (2011-2013). The above 180 day transit estimate is based on readings made during the approximately 8 month/240 day MSL transit, a trip propelled by a chemical rocket, the Centaur, an RL-10 engined upper stage of the Atlas V.<ref name="SCI-20130531a">{{cite journal |last=Kerr |first=Richard |title=Radiation Will Make Astronauts' Trip to Mars Even Riskier |url=http://www.sciencemag.org/content/340/6136/1031.summary |date=31 May 2013 |journal=[[Science (journal)|Science]] |volume=340 |page=1031 |doi=10.1126/science.340.6136.1031 |accessdate=31 May 2013 |issue=6136}}</ref><ref name="SCI-20130531b">{{cite journal |title=Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory |url=http://www.sciencemag.org/content/340/6136/1080.abstract |journal=[[Science (journal)|Science]] |date=31 May 2013 |volume=340 |pages=1080–1084 |doi=10.1126/science.1235989 |accessdate=31 May 2013 |author=Zeitlin, C. et al. |issue=6136 |last2=Hassler |first2=D. M. |last3=Cucinotta |first3=F. A. |last4=Ehresmann |first4=B. |last5=Wimmer-Schweingruber |first5=R. F. |last6=Brinza |first6=D. E. |last7=Kang |first7=S. |last8=Weigle |first8=G. |last9=Bottcher |first9=S. |first10=E. |first11=S. |first12=J. |first13=J. |first14=C. |first15=A. |first16=S. |first17=G.}}</ref><ref name="NYT-20130530">{{cite news |last=Chang |first=Kenneth |title=Data Point to Radiation Risk for Travelers to Mars |url=http://www.nytimes.com/2013/05/31/science/space/data-show-higher-cancer-risk-for-mars-astronauts.html |date=30 May 2013 |publisher=[[New York Times]] |accessdate=31 May 2013 }}</ref>]]

I didn't remove it, but I'm guessing that they said it was irrelevant because that's not what this article is about. It's not about a Mars mission, it's about a rocket. That image would be a great addition to the various crewed Mars mission articles (and there are many of them). The Mars One article would be a good place to start, and move out from there. — Gopher65_talk 01:30, 22 February 2014 (UTC)

• Right, there nothing in the caption that really ties it to SLS and the figure would better fit in another article, imo. -Fnlayson (talk) 03:21, 22 February 2014 (UTC)

I put it in the criticism section of this article, on an in-development rocket/launch vehicle, because as a Mars mission is likely to be on the cards for the Block II of the SLS, the choice of engines on the vehicle for mars transfer is important. If they go with chemical engines without an ability to do high delta V changes in velocity, then the crew will be exposed to a fairly high, some might regard, unacceptable risk. Are you guys saying that if I pull in a reference that deals with the radiation hazard as a factor on the choice of engines for the SLS upper stage, mars transfer vehicle then I can flesh it out in the article?

Like this, round trip with NTR nuclear thermal rocket engine estimated to be as low as 200 days, therefore 1 way transit about 100 days.

Total interplanetary trip time is dependent on how long the astronauts stay on the surface of Mars, most design studies with the shortest trip time have them staying no more than 20 days.

https://web.archive.org/web/20090302093708/http://www.inspi.ufl.edu/news/UF%20RESEARCHERS%20NUCLEAR%20POWER%20WILL%20MAKE%20MARS%20TRIP%20SHORTER,%20SAFER.htm

and this https://web.archive.org/web/20081011124255/http://www.fas.org/nuke/space/c07sei_4.htm

http://ares.jsc.nasa.gov/HumanExplore/Exploration/EXLibrary/DOCS/EIC031.HTML

Alternatively a chem propulsion CPS would result in a total of 365 days incl return. http://www.astronautix.com/craft/marion88.htm

83.71.31.172 (talk) 23:49, 24 February 2014 (UTC)

An off-topic arguments on content in Criticism section

My least favorite part of the criticism section is the propellant depot idea. First of all, any propellant depot in low Earth orbit would experience orbital decay and eventually fall back to Earth. Second, with the announcement of EmDrive it appears that spacecraft propulsion may not need any propellant at all once the spacecraft arrives at low Earth orbit assuming it has sufficient solar power. Brian Everlasting (talk) 02:18, 6 August 2014 (UTC)

*sighs*. Ok, so once again, EmDrive isn't real.

• 1) The NASA team had a better test setup than the Chinese team, and saw 1000 times less thrust for the same power input. When better experimental setups eliminate most of the effect in question, that's usually an early sign of a death keel. It indicates that the initial tests were shoddy, and that they weren't properly controlling for all the variables. This means that you can take the Chinese results and huck them in the garbage, because they did a terrible job of testing their unit.

• 2) The "researchers" (if you want to call lazy bums like that researchers) that NASA had testing the EmDrive didn't bother to test it in a vacuum. Why? Sheer and utter laziness. They mentioned in their paper that they should have, they just couldn't be bothered to do it. Why? They'd have had to replace a few capacitors before the test. So what did they do? Why, they tested it in a vacuum chamber, but didn't turn the chamber on of course. That's what any of us would have done, right? FFS. (I would have fired them all for this. And blacklisted them for their shoddy work.)

• 3) About the one thing the NASA "researchers" did correctly (were they first year undergrads there on an internship? Cause that would explain it) was to build two test articles. One of them was designed to work, while the other one was a dummy unit. When they put power into them both units saw thrust. That shouldn't have happened if the microwaves were what was causing the anomalous thrust that was seen. This likely indicates that unaccounted for atmospheric effects were the dominant cause of the thrust that was seen.

They saw a very, very tiny effect. One that could easily be explained by the fact that they were too damned lazy to turn on the vacuum chamber. This is because the container holding the microwaves is asymmetrically heated by the microwaves. The hotter side of the container experiences some abnormal air currents, which then push the container away, generating "thrust". It's essentially a simple version of a Crookes radiometer.

So until they've until they've tested it in a vacuum chamber, EmDrive isn't a thing. Preferable tested it with a team of different people that isn't comprised of Beavis and Butt-head. If, after that is done, they still see an unexplained thrust, *then* we can all start to get excited. But not yet:P.

If you can't tell, I'm extremely disappointed in the poor quality of research done by this bottom of the barrel NASA team. And I'm not the only one. — Gopher65_talk 03:29, 6 August 2014 (UTC)

Propellant depots - Propellant depots are a well-examined idea, and one advantage is that containers can be standardized and RFPs put out for delivery prices to a certain location. Orbital decay is not an issue; you launch propellant to where you need it and you can use cryogenic venting for long-term station-keeping. They're just gas stations, which have worked well for the world. They are absolutely a viable and extremely cost-effective alternative to a heavy lift vehicle.

EMDrive - Currently has no place in this article, but frankly the Eagleworks article withstood a long period of peer review before being published. Impulse response was immediate and coincided precisely with application of the on/off switch, and hence is unlikely to have been thermally-related. You're mistaken about the nature of the Cannae control unit; it wasn't a dummy, it just didn't have the radial slits. The data and the researchers have already withstood more-informed criticism, although as the researchers point out, it remains to be seen whether the drive will be determined to be real or revolutionary. Your sighs are duly noted. Voronwae (talk) 03:47, 26 November 2014 (UTC)

Block IB lift capability to LEO

We have some pretty wild claims being made about the payload lift capability of the Block IB with the Exploration Upper stage. I believe the discrepancy between 93.1 & 118 tons to LEO is due to the sources that cite the first reference referring to actual payload and the latter to sources including payload+the fuel and engine weight of the Exploration Upper stage. Naturally seen as 93.1 is the payload to LEO capability this is the more accurate figure.

In any case, we need to clear up exactly what payload capacity to LEO the Block IB SLS will have - [which is presently a vehicle architecture with the Exploration Upper stage 2nd stage combined with the core stage's four RS-25 engines and dual 5(or 5.5) grain segment shuttle derived SRB's] - will really be capable of.

Thoughts? 178.167.254.30 (talk) 14:14, 21 August 2014 (UTC)

My understanding is that they're currently leaning strongly in favour of building the block 1 (70-some tonnes to LEO), waiting 20 years, and then maybe building block 2. Maybe. But probably not, since it's believed several more advanced, more capable, cheaper commercial alternatives will have long been in use by the time funding for the block 2 materializes. The block 1B had been deprecated (last I'd heard), and they have no plans of building it due to lack of funding. — Gopher65_talk 14:43, 21 August 2014 (UTC)

Block IB is scheduled to fly as the second SLS mission, as reported extensively just a few months ago. The reason we don't have performance figures that agree is that the 93 ton capacity is from a study comparing several possible upper stages, none of which is exactly the EUS, which we don't know the actual performance of yet. The number will be clarified as the EUS design progresses (or is cancelled, who knows) A(Ch) 17:28, 26 August 2014 (UTC)

"The SLS will launch the Orion Crew and Service Module and may support trips to the International Space Station if necessary. " Really? I haven't read any mention of plans to lift modules to ISS, although I suppose it's possible. Certainly it's many times too large for crew. Can someone cite justification for the second half of this sentence? Voronwae (talk) 03:16, 26 November 2014 (UTC)

Service Module is part of Orion stack and has nothing to do with ISS. Doyna Yar (talk) 04:28, 26 November 2014 (UTC)

Criticism section

It's not our job to deconstruct published criticism, just to record it if relevant. The critisicm section looks to be pretty well cited and referenced, and as a government program, published criticisms from industry figures ARE relevent and noteworthy. Recording that there has been critisicm of the program does not affect the article's NPOV, therefore I have removed the rewrite tag. Jmackaerospace (talk) 15:11, 24 August 2014 (UTC)

That's not the point of the tag. The coverage in the section is unbalanced. See the previous posts above and on the archive page. -Fnlayson (talk) 15:42, 24 August 2014 (UTC)

the above is OR it has nothing to do with the content of the article. If you think the critisizm section is unbalanced, pleasee tag it to be re-written for greater balance - the current tag asked for it to be integrated wih the main articlee, which would mess up the NPOV of the whole article. Sorry for spelling, using phone, buggy. Jmackaerospace (talk) 08:52, 25 August 2014 (UTC)

Right, I have added a section POV template which is more in line with what you seem to think is the problem. Suggest you read Wikipedia:Criticism_sections#Approaches_to_presenting_criticism because as previously stated, I can see no problem with this section as written.Jmackaerospace (talk) 09:36, 25 August 2014 (UTC)

That's fair, and I've read that times before, but not recently. In practice Criticism sections can become magnets for negative coverage without balance. This section discussed in the 'Neutrality' in the archives ~2 yrs ago and edits/changes were made. But there's still no counter arguments and primary sources are heavily used. -Fnlayson (talk) 15:33, 25 August 2014 (UTC)

SpaceX HLV

While SpaceX respectfully is making great strides in the industry their HLV is very much on the vaporous drawing boards and far from even a prototype. In time it may be relevant, but I don't think it belongs here at this time. Doyna Yar (talk) 02:57, 31 August 2014 (UTC)

The SLS is vaporware itself. Even odds that the next president cancels it, or that the Tea Party (which hates it), gains enough sway in the House to slash its funding. The SpaceX BFR is a good decade away though, so it's vaporware as well. But we write articles about vaporware, as long as it's notable in the media. And I'm certain the SLS qualifies, and the BFR probably does too, even though it's at an earlier stage of development. — Gopher65_talk 03:09, 31 August 2014 (UTC)

I guess my 'vapor' usage hit a nerve. My point simply is SLS is under fabrication and quite tangible regardless of political speculation at this time. The SpaceX HLV isn't beyond the conceptual. Because someone journalistic draws some kind of speculative competitive relation to fluff up an article does not make it relative especially when SpaceX confirms no intentional competition with SLS. You may as well include the Long March 9 130K LEO rocket as well which is just as conceptual unless I'm right and that too is not relevant at this time. Of course under the right political environment it could be postulated Americans could go to Mars on a Chinese HLV. Pardon if I don't hold my breath. You can't have it both ways. For now this is an article about the SLS program. I view the comparison as of today as tabloid. Aside all that I don't see a class comparison between 53,000 to LEO and a base of 70,000 LEO that is planned to expand to 130K and remotely 150K. That sounds like different rocket classes to me. If and when SpaceX begins real world development of their HLV and when NASA or Congress would consider it an alternative to SLS it becomes relevant to the article. I would accept their HLV may become complimentary to the NASA roadmap, but no substitution for SLS. Move it to See also. For what it's worth that's my opinion. Doyna Yar (talk) 03:26, 3 September 2014 (UTC)

There are no plans to expand the SLS to 130 tonnes. Block II has been put on indefinite hold. (To give you an idea of what "indefinite hold" means at NASA, both VentureStar and JIMO are on indefinite hold. And they always will be.) Not only is it not under development, it isn't even planned to be under development. So this isn't a 130 (or 150) tonne to LEO rocket. It is a 70 tonne to LEO rocket that has one planned launch (which might, *might* occur in 2018... maybe), and might have one additional launch in a 90+ tonne to LEO configuration. Maybe. Few "in development" rockets have ever been as vapourware as the SLS. — Gopher65_talk 02:48, 4 September 2014 (UTC)

If you are sure you are correct please feel free to blank any sections of the SLS article that doesn't fit your narrative. I promise 'I' will not revert any of your edits. Have fun with that. Please don't bother replying- I just stated my opinion, it's not a conversation... do what ever you want. Doyna Yar (talk) 03:45, 4 September 2014 (UTC)

I don't think that "hitting a nerve" with comments on the Talk page is very relevant. A media source has noted that there may be some competition for American HLV vehicles, and possibly two of them, in the 2020s. The brief mention of that currently in this article does not seem unduly weighted, is verifiably sourced, and seems to state only that basic fact. After all, neither vehicle is flying today, both are only in early stages of development with flight years away. So given that Wikipedia is not censored, I would think it quite appropriate to leave the mention of the competitive vehicle in the article. Cheers. N2e (talk) 04:15, 6 September 2014 (UTC)

It does strike me as undue weight that a single paragraph with a single source should have a first level heading devoted to it, though. Especially since SpaceX goes out of their way to disavow any competition with SLS. Maybe when we get more solid details about BFR, but a heading on "competition" seems very premature. A(Ch) 05:12, 6 September 2014 (UTC)

That makes sense. Where do you propose it goes? Since it does not seem to fit under any of the other headings, and is not appropriate for the lede, is there some other section heading under which this (and possibly other material too?) could fit under? N2e (talk) 13:39, 6 September 2014 (UTC)

Honestly I think it's too early to be included at all. We don't have solid information on BFR yet. Even the NSF article doesn't include any specific way in which SLS and BFR would compete - it's a history of SLS followed by what we know/speculate about BFR. Of course as a spaceflight enthusiast I'm rooting for SpaceX to make Mars happen, but we can't compare the merits of the vehicles because we don't know enough about BFR. We can't say they're competing because what're they competing for? We can't say one is cheaper than the other because who knows? An NSF article making vague remarks about competition doesn't tell us anything about SLS. Let things play out, then we can say what, if any, effect BFR has on SLS and vice versa. Until then it seems to me that anything other than a one sentence mention somewhere that SpaceX is planning on building a rocket with similar lift capabilities to SLS is giving undue weight to the issue. Of course I hope that changes if SpaceX really does what most of us hope it will, but right now there's really not much to say in an article about SLS, and certainly no competition to speak of. A(Ch) 16:44, 6 September 2014 (UTC)

Yikes I ramble when sleep deprived. TLDR I concur with SkywalkerPL. A(Ch) 20:55, 6 September 2014 (UTC)

It even needs to be there? Space Launch System#Criticism got already covered a topic of SpaceX and a fact that Falcon Heavy is the competitor. I say: Remove whole section. It's completely redundant. SkywalkerPL (talk) 16:10, 6 September 2014 (UTC)

Well it clearly doesn't need its own top-level section, but I don't believe removal is the right thing to do. It's clearly verifiable, and Wikipedia is not limited by disk space, nor censored. The idea of political competition between the two in the American politico-sphere is clearly noteworthy. So I'm thinking it might fit somewhere in criticism or in political consderations. Cheers. N2e (talk) 19:38, 8 September 2014 (UTC)

That sounds about right. I wouldn't give it undo consideration though. Maybe one sentence. It is, after all, not a real rocket yet. — Gopher65_talk 23:37, 8 September 2014 (UTC)

Look at the comment from Anythingcouldhappen up above my. One that starts with "honestly I think it's too early to be included at all". Other than all of the arguments mentioned there - the article in source for this section is mostly original research of it's auther with rather poor factual background supporting said conclusions instead opting for using self-references and building content on a base of some posts from the NASAspaceflight forum. I'm very concerned that this section doesn't fulfil the criteria of Verifiability. As I said earlier - it's redundant to the #Criticism section in it's verifiable and objectively true points. SkywalkerPL (talk) 10:04, 9 September 2014 (UTC)

Funny, no mention, debate, or issue in the Falcon Heavy page. Hell not even a mention of SLS..? Hint and a half if the SpaceX junkies aren't playin' it up you're not getting enough oxygen citizen. Just add Falcon Heavy's page to See also and lets just wait and see. Yeesh! Doyna Yar (talk) 03:20, 9 September 2014 (UTC)

If you have any sources that can counter the arguments in Space Launch System#Criticism section then feel free to provide them - this article is in a desperate need for them. SkywalkerPL (talk) 10:04, 9 September 2014 (UTC)

I don't believe any sort of full consensus was reached in the above discussion on what to do with the "Competition for an American heavy-lift launch vehicle" section of the article, although there were some elements of agreement. Moreover, much of the discussion above was not even about that section, which started this discussion, but about other topics, including "Criticism" of the SLS and how the much-smaller Falcon Heavy may or may not compete with the SLS. While these may be relevant topics for the Talk page, they should be discussed in some separate section, not in the section discussion "competition" that may emerge in the 2020s from the MCT and SLS.

Just today, I observed that someone made a rather major edit based on a "suggestion" made in the above section, but which did not have widespread consensus. I have added that deleted material back into the article, and have started a discussion below, per WP:BRD. Please join that discussion if the topic of "competition" or the "MCT and SLS as both being >100 mt launch vehicles potentially available from American producers in the 2020s" interests you. Cheers. N2e (talk) 05:35, 23 September 2014 (UTC)

It did not have a consensus? As far as I see - it did. No new arguments were presented against removing the content, and these concerns that appeared - were already addressed and no new opposition against it was posted. As far as I see - changes made by User:Fnlayson were fully justified. Restoring. SkywalkerPL (talk) 10:59, 23 September 2014 (UTC)

Ok, I just noticed you, N2e, posted stuff in a new section. Please, keep everything in one place. I moved it below as a subheader. Discussion on topic should stay here, otherwise it's way too easy to miss. SkywalkerPL (talk) 11:05, 23 September 2014 (UTC)

BRD discussion on recent deletion

I have added back a section that was deleted in an edit on 14 September 2014 by User:Fnlayson. I assume good faith. Suggest we discuss it further here, per WP:BRD, and see if perhaps smaller changes can't be proposed and consensus obtained.

• I do not believe that a consensus existed on this Talk page for such a radical change. See discussion above in Talk:Space_Launch_System#SpaceX_HLV, from 31 Aug thrugh 9 Sep 2014.
• I do not think that the emergence of another Super Heavy Lift Launch Vehicle on the American scene is in any way a criticism of the Space Launch System, so in any event, the material here would not fit in the "Criticism" section.
• I do believe that some changes could be made to improve that section, and perhaps keep it from being in a "==Section heading=="-level section. But unfortunately a subsection of the existing "Criticism" section is not going to work, since in no way is the material in that section related to any criticism of SLS, by any identifiable person or persons or company. The article even says SpaceX has gone out of their way to avoid placing the MCT in direct comparison with SLS. It seems to be media analysis that have begun to do so here.
• I don't believe the existing section overstates the case. The prose is merely noting that "... media sources have noted that the US launch market may have two competitive launch vehicles available in the 2020s to launch payloads of 100 metric tons (220,000 lb) or more to low-Earth orbit. The privately-funded SpaceX MCT launch vehicle powered by nine Raptor engines, has also been proposed for lofting very large payloads from Earth. While SpaceX plays down the competitive aspect with SLS, if SpaceX makes progress on its super-heavy launch vehicle in "the coming years, it is almost unavoidable that America’s two HLVs will attract comparisons and a healthy debate, potentially at the political level". This seems, to me, a rather measured and limited statement about an indubitably verifiable item.

So to start with, how might we incorporate this material on this competitive aspect into the article, as some subsection that doesn't imply it has anything to do with criticism?

Cheers. N2e (talk) 05:27, 23 September 2014 (UTC)

As per my previous post:

• Consensus was reached - remove the content.

On the contrary, there was no consensus in the section above this BRD subsection to remove the content. For example, when the topic was, as it started out, the MCT launch vehicle potentially providing competition in the 2020s for the >100 mt version of the SLS, you can clearly see the lack of consensus right in the first four comments. Later on, the discussion became less tight when it was widened in comments by a couple of editors who added a different topic (Falcon Heavy, and competition in the considerably-under 100 mt sector of the launch vehicle classes), and a different section of the article than had been discussed in the previous half-dozen posts (the one entitled Competition, not the one that at the time was entitled Competition for an American heavy-lift launch vehicle). However, a wider discussion, with unhappiness about emphasis of Falcon Heavy etc. in some entirely different article section, albeit expressed by a couple of editors, does not make a consensus to remove the content on competition of a different launch vehicle in the >100 mt segment in the 2020s. N2e (talk) 11:36, 25 September 2014 (UTC)

• It's not a matter of criticism or not, it's a matter of verifiable content, and as both: me and A(Ch) tried to point out - this section doesn't fulfil the criteria of Verifiability and it's too early to include a section like that even if we'd assume that this section is suppose to be included at all.
• One opinion doesn't make a "media analysis". And as A(Ch) rightfully pointed out - it's whole lot more complicated than you try to make it in your reply.
• Read previous discussion, it was already addressed. It's a whole section, not a `mere note` as you suggest, and.... read below (Falcon Heavy is already mentioned in the article).

I don't know what sort of bad blood may have been going on in this article, or this Talk page, for some time; but I know I haven't been involved with it, and am not even aware of it. As I noted above, the discussion of this section, and the couple of sentences added to the article about the potential competition in the >100 mt sector, in the 2020s, from the MCT launch vehicle, has nothing whatsoever to do with the Falcon Heavy. I don't really understand how that got conflated in the discussion. But it does seem to me that some sort of ongoing argument(s) of editors that had been going on for some time got added to the much smaller scope changes and discussion about 2020s competition in the >100 mt space. N2e (talk) 11:36, 25 September 2014 (UTC)

"So to start with, how might we incorporate this material on this competitive aspect into the article" - I don't see any point of incorporating it.

Let's tear it apart for a moment:

• First sentence - fact that Falcon Heavy is related to SLS is already addressed by the article, so it's nothing more than a duplicated content. Other than that maybe I'm missing something but the source doesn't mention anything about other "media sources" that would "note" anything about the "100 metric tons" launch vehicles - it's completely unsourced statement.
• Second sentence is just an advertisement of SpaceX, irrelevant to the topic.
• Third sentence is a private opinion of a few NASASpaceFlight forum members (which is directly pointed out in the source itself + the fact that an author is one of most notable members of that forum). Unless it can be verified by independent sources (other than the forums) to actually show that is has anything to deal with "media analysis" (as opposite to personal opinion of one forum member) - it should be removed. Also: refer to my comment from 9 September 2014. If you can find sources confirming statement in this sentence - it can be incorporated into the criticism section (which already mentions debates) with proper sourcing.

Your bullet list here illustrates my point. The discussion of the Falcon Heavy and the under-60 mt competition provided by that with the lower-end/initial 70 mt SLS in the 2010s somehow got conflated into an entirely different discussion. Apparently, there is some sort of a deep history around these parts with arguments about Falcon Heavy. I have not been, and am not now, involved in any of that. The original change being discussed in this section was about a few sentences added to the article about an entirely different LV in the >100 mt sector of the space a decade from now. N2e (talk) 11:36, 25 September 2014 (UTC)

I don't see how it fulfills Wikipedia quality standards to the point where you'd want to keep it in the article. I understand it mentions private aerospace company so it's related to your interests, however you shouldn't allow your personal point of view to interfere with objective verification of the content. SkywalkerPL (talk) 11:49, 23 September 2014 (UTC)

Careful here. I think you are treading on thin ice. I suspect you know that we should be discussing content, not editors as we endeavor to improve the encyclopedia. I think I can say with certainty that this is what I have been doing. Casting aspersions on another editor's motive may be viewed as a personal attack, and in any case only detracts from the substantive discussion. If on the other hand, you believe any editor is violating Wikipedia behavioral guidelines, then the place to take that up is at WP:ANI. N2e (talk) 11:36, 25 September 2014 (UTC)

I read your reply (all parts of it) and all I see is discussing editors, not content. You added nothing constructive on a topic. If you'd like to address any points - please do, because in this latest reply of yours I don't see you addressing anything other than people taking part in the discussion and quoting Wikipedia rules we'll all aware of. SkywalkerPL (talk) 11:43, 25 September 2014 (UTC)

The MCT text was only shortened to a sentence that the source covered and put with the other SpaceX text as suggested above (after proposed Falcon XX heavy launch vehicle, which seems related). The Criticism section probably does need a more general name, like "Criticism and alternatives" to match the content there. -Fnlayson (talk) 13:47, 23 September 2014 (UTC)

@Fnlayson:—regarding your specific suggestion about broadening the name of the existing Criticism section to reflect the full scope of what is discussed there, that is a good idea, and I would certainly support it. Moreover, it would narrow the breadth of the substantive discussion on which editors may disagree here. So if that clarification is not controversial to others, then once it is made, it certainly will make the other conversation smaller by one issue.

Fnlayson—I see you have made a change to the second-level section heading, to Competition and alternatives. I support that change! And with that change, assuming in sticks, then any discussion of the MCT LV offering some sort of competition for the >100 mt super-heavy launch vehicle segment in the 2020s would clearly now fit somewhere within that section. Thanks. N2e (talk) 11:36, 25 September 2014 (UTC)

I will make a substantive response on the broader set of topics under discussion by SkywalkerPL when I have some time to address the several issues he mentions. N2e (talk) 16:56, 23 September 2014 (UTC)

I finally got back here and made those comments today, and inserted them inline, as this entire section seems to have become muddled, and is discussing a number of topics that have nothing to do with the original small amount of prose in the article about the potential competition in the >100 mt segment of the LV space in the 2020s. N2e (talk) 11:36, 25 September 2014 (UTC)

Is there a precedence for something like that? Usually alternatives are put simply in a bulleted list of "comparable rockets". What you are suggesting is a very clever compromise between "let's devote a section to SpaceX" and "let's not" but I don't see a reason why SLS article should put so much pressure on the fact that SpaceX might or might not have an alternatives - it's an article focusing on SLS after all, isn't it?

If anything - I would suggest adding Comparable rockets section similar to Delta II#Comparable rockets made of rockets from #See also plus additional Falcon XX (proposed) on the list along with whatever else is missing. References can be added where applicable.

I see absolutely no reason why so much pressure should be put on SpaceX ideas in this article as opposite to any other rocket. Perhaps I'm seeing bias that doesn't exist on a wikipedia, but somehow none of the articles about SpaceX rockets got anything remotely similar to what's being discussed here nor even the section about Falcon XX mentions anything about how it's threatened by a competition from SLS, or actually - it doesn't mention SLS anywhere at all. I'm honestly surprised one one-sided this whole thing is. SkywalkerPL (talk) 18:24, 23 September 2014 (UTC)

I see where you're coming from, but other articles don't mention the SLS as a competitive threat because, well, it isn't one.

• Estimated SLS costs, including first 4 flights: 41 billion dollars, not including the Ares V development costs that weren't transferred to the SLS, even though Ares V tech is being used on SLS (it's literally, literally one of the proposed Ares V lite variants, just renamed). That does however include Orion, and some launch pad upgrades (estimated 2 billion). These are NASA's own internal predictions, so they're probably fairly accurate, if a little on the optimistic side. They usually undershoot the actual costs by a bit.

• Estimated BFR costs, including first 4 flights, based on (likely very optimistic) SpaceX past statements: 2.5 billion + 500million*4 = 4.5 billion.

The costs are not in the same league. Both 41 billion and 4.5 billion are likely underestimates, but it's pretty clear even from those estimates that the BFR (if developed) wouldn't have to worry about any competition from the SLS. That's why no one ever writes articles saying "SLS is going to kill off BFR", but an article comes out every month saying "BFR is going to kill off SLS".

Personally I don't think that BFR deserves much mention in the media, because it hasn't even been announced yet. But it has been mentioned, and often. Remember, we aren't here to judge what people are thinking, we're here to report it in any unbiased way. And the unbiased report on this subject is this: everyone in the community is wondering whether SLS will even launch (NASA engineers are reported to be rooting against it, because they think it's a waste of money and their time... they want to be working on something cool like Nautilus-X). And if it does launch, the general bet is that it will only launch once, maybe, MAYBE twice before it's killed off. At an estimated 1.5 billion per launch (~20 billion per launch including dev costs), it's not going to get many launches. That's what everyone is thinking, and that's what the media is reporting, so that's what we write here. — Gopher65_talk 23:05, 23 September 2014 (UTC)

Is anyone else getting a headache? "other articles don't mention the SLS as a competitive threat because, well, it isn't one." *Homer* 'doh!' Apples and oranges. Captain Obvious, wasn't that my whole point all along? I can't believe I'm adding anything to this argument again. One article with a whole lotta supposition by the author and absolutely no support from anyone in the industry public or private does not cut it. I have no problem with the article saying vaguely something along the lines that there may be 'some' future private competitor when SLS comes online. But until that is tangible or at least more broadly speculated by the media it's a joke. I still say just have a 'See also' link to the spacex rocket proposal and wait. That's my uneducated 2 cents and you are all welcome to take it any way you choose. I'll have nothing to do with the editing on this issue. Doyna Yar (talk) 04:04, 24 September 2014 (UTC)

We already have arguments you mention in the article. But everything has two sides of a coin and as I said - somehow the other one isn't presented. You think that SLS isn't a threat to SpaceX ideas of replacing it with Falcon derivatives? I found a source to prove contrary in 30 seconds: http://www.americaspace.com/?p=34964 . And as I said - somehow none of the arguments for SLS are mentioned anywhere - neither in this nor on any of the SpaceX articles. Besides, let's face it: we're comparing a rocket that's in final stages of it's development against what's either still in a design work (Falcon Heavy) or just an idea that didn't even go through preliminary studies (Falcon XX). SLS will launch - it's already pretty much closed case. As for the future beyond that - it's pretty much all just a pure speculation with little to none data supporting it, regardless if you think that SLS will have successful career or it'll be launched just once. And never say "That's what everyone is thinking" unless you have an actual sources to support it. Pulling statements like that out of nowhere stands against multiple polices on Wikipedia including Wikipedia:Verifiability, Wikipedia:No original research and Wikipedia:Neutral point of view. SkywalkerPL (talk) 07:54, 24 September 2014 (UTC)

A few points:

1) Again, this isn't about what we think, but rather specifically industry (spaceflight industry) opinion on the subject. In other words, expert opinion. That's not any of us here, and even if it were, we can't do OR (at least not on pedia:)). Since Wikipedia favours secondary (media) sources over primary (press releases, or statements from company officials/NASA), that ends up meaning this: "hmmm. There are 99 main stream media articles favouring this opinion, and 1 article on this one. Therefore we'll weight 99% of this section of the article toward the opinion favoured by 99% of the articles".

2) Falcon X and Falcon XX aren't real, and never were. They were nothing more than an offhand comment years ago, by one SpaceX official. They never even made it to the paper rocket stage of development. They also aren't what people are discussing when they talk about a SpaceX BFR.

3) The BRF is under active development. Its engine components are already being tested, in fact. So there is actual hardware. About the same amount of actual hardware as exists with SLS currently, in fact (very little for both rockets. That's why I refer to both of them as paper rockets). BFR (a rocket whose name hasn't been released, so the community (and SpaceX, actually) call it "Big F***ing Rocket") is a 200 tonne to LEO rocket. Publicly released details are scant, but point to a rocket powered by a giant staged combustion methane/LOX Raptor engine, with a 14 meter core (huuuuuuuuuuuuuuuuuge. Way bigger than it needs to be IMO). Not much else is known.

4) The Falcon Heavy will launch in about 6 months. Final hardware is already either done, or nearly done.

5) And finally, I disagree with the weight given to the BFR in the media. It is not a real rocket, and should receive only the most minor of discussion in the media until it is at the very least publicly announced by SpaceX. But I'm not the one writing all those articles:P. The fact is that BFR has been mentioned, and far, far too often. I wouldn't have written an article about BFR at all yet, but it's been mentioned too many times in the media to ignore. — Gopher65_talk 13:00, 24 September 2014 (UTC)

There's actually one other strong reason that I forgot to mention why SLS can't complete with any commercial rocket, not just SpaceX's unnamed paper BFR. By law, if a cheaper American commercial alternative exists that can launch NASA payloads, NASA is *required* to give preference to it over their own rockets. Anyone, ULA included (the most expensive commercial launch provider in the world), can develop an SLS alternative that will launch for less than 1.5 billion a flight. If *anyone* flies a rocket that can carry NASA payloads cheaper than SLS, NASA will have no choice but to use it.

In the real world, I suspect politicians could weasel their way around that law if they had to. — Gopher65_talk 00:08, 25 September 2014 (UTC)

Yes, it's about what the industry thinks, that's why all of the points of view need to be represented, not just one. And it's nowhere near to 99 vs 1 opinions split as you suggest. Wikipedia:Verifiability and Wikipedia:Neutral point of view are polices not an optional features that you include in the articles or not based on whatever you think that either "everyone" or "99 main stream media" share your point of view. I have absolutely no interest discussing what you think about SLS, what are your thoughts about BFR, Falcon Heavy, Falcon XX or SpaceX as a whole.SkywalkerPL (talk) 10:08, 25 September 2014 (UTC)

Oh, and just to be clear, cause it seems that we have a misunderstanding here - I'm not disputing criticism against SLS, especially if it's well sourced, I'm disputing the fact that it's extremely one-sided with no counterarguments even though they clearly do exist. And just to remind you Gopher, cause you clearly go way over the board: SkywalkerPL (talk) 10:20, 25 September 2014 (UTC)

I will just note that the above Talk page section has become such a mess, with a discussion of a VERY wide variety of topics well beyond the quite narrow topic of the BRD on a few lines of article prose, and with (apparently) a lot of history and previous unsettled arguments brought into the mix, that for me, it's not really possible to continue having a rational discussion on the much more narrow topic that was originally under discussion in this section. YMMV, but if I have more to say, I'll likely say it somewhere where the topic breadth can be clearly limited to a single item at a time, and hopefully avoid the discussion being joined by a lot of history of previous (unfinished?) discussions that are unrelated. Cheers to all of you, N2e (talk) 11:36, 25 September 2014 (UTC)

So far the first person I seen making a posts that don't address anything at all on topic of the discussion is You, N2e, so I find your post very ironic overall, however I do agree that both topics of the discoussion: Competition for an American heavy-lift launch vehicle section and lack of counterarguments in Criticism section went the point where nothing more can be agreed through continued discussion. I'm out from here too. SkywalkerPL (talk) 11:57, 25 September 2014 (UTC)

Initial Launch date window pushed back

Just so everybody's aware, it looks like NASA's pushed back the initial launch date of the Block 1 SLS to November 2018, and that has the potential to push back all the subsequent mission dates as well. I haven't changed anything in the article, as the source below doesn't give a definite date that it's pushing to. You can read the article below: http://news.yahoo.com/nasa-says-heavy-lift-rocket-debut-not-likely-230603632.html — Preceding unsigned comment added by The.famous.adventurer (talk • contribs) 09:51, 31 August 2014 (UTC)

That date is already listed in the mission table. The delay just means that the end of the window for the launch was extended to 2018. Late 2017 is still the working date according to a Aviation Week article on this. -Fnlayson (talk) 12:14, 31 August 2014 (UTC)

Shuttle-derived?

SLS

To me it looks more like it was derived from the Saturn instead of the Shuttle. It looks a lot like a Saturn with two boosters strapped on. Bubba73 ^{You talkin' to me?} 04:27, 14 September 2014 (UTC)

Click on the Shuttle-derived link in the first sentence of this article and read that page. -Fnlayson (talk) 22:34, 14 September 2014 (UTC)

Unless the F-1 advanced liquid boosters get chosen there is probably no Saturn linage short of Michoud Assembly Facility and NASA logo. Doyna Yar (talk) 03:35, 15 September 2014 (UTC)

Take the side boosters off and it sure looks like something in the Saturn family. Bubba73 ^{You talkin' to me?} 01:32, 16 September 2014 (UTC)

Well reluctantly I'll give you that SLS form factor is very much constrained by the VAB from the Saturn program. I'm not sure where your line of logic is going with this in relation to the article? Doyna Yar (talk) 03:30, 16 September 2014 (UTC)

Not much really, except that Saturn V#Proposed successors lists it as a proposed successor to the Saturn V, and it does resemble it quite a bit. Bubba73 ^{You talkin' to me?} 04:34, 16 September 2014 (UTC)

Whether or not the SLS is Shuttle-derived, is it accurate to say (in the first paragraph) that it's a replacement for the Shuttle? Wasn't the Shuttle limited to NEO? Misterjag (talk) 05:15, 17 December 2014 (UTC)

SkywalkerPL (talk) 09:01, 16 September 2014 (UTC)

Block IB again

The 93 tonne figure for Block IB comes from an analysis conducted before the selection of the EUS, and does not reflect the stage's design or capabilities. For example, the study assumed 105 tonnes propellant - the current design allows for up to ~130 tonnes of propellant. Right now we really have no idea what the capacity of Block IB will be and should not be listing estimated payload, except to point out that an analysis of an upper stage (not the EUS) with four RL10 engines indicated a payload capacity of around 93 tonnes. There are no reliable sources for the actual estimated capacity of Block IB yet. A(Ch) 05:52, 8 November 2014 (UTC)

Agreed, but the 118 ton payload to LEO(low earth orbit) figure you've been misleadingly inserting into the Block IB section in this article and in the (EUS)Exploration Upper Stage article, was not at all supported. I'm glad you now acknowledge that was not at all supported. Therefore I, the Irish IP user, had to go and remove the wild & unsubstantiated claim of "118 ton" to LEO, which you were pushing.

Lastly, you know you can simply calculate to find out, and get the ballpark payload figure to LEO for the Block IB of at least 97 tonnes when afforded by the EUS's 130,000 kg of propellant. As we know that the preliminary-DUUS(dual use upper stage, which although is technically "not the EUS", it is identical to it, apart from simply having less propellant) was determined by Boeing to be able to lift 93 tons to the same orbit with 105,000 kg of propellant.

86.45.185.173 (talk) 08:22, 17 December 2014 (UTC)

Add 'expendable' in the opening paragraph?

As reference [24] indicates that nothing from the proposed vehicle is recovered during the launch, perhaps it is appropriate to add the term 'expendable' in the opening paragraph, and remove any reference about reusability in the article. 217.239.14.72 (talk) 00:21, 28 November 2014 (UTC)

Took me a while reading the article to figure out that there's nothing reusable in the design. For all the hype, isn't this much the same as good old Saturn V and that article uses "expendable" in the lead.

Mishmash of units: 'metric ton' and 't', lbs and kg, etc

Really confusing having 'metric ton' and 't' used in the same article - would be better if one form were used consistently. As this is a US project, unfortunately it would seem that the SI 'tonne' may not be an acceptable form to use, however clear it might be. I would suggest that perhaps the first instance is written as xx metric tons (tonnes, t) so that more readers will grasp the units used, then subsequently use 't' for brevity. My feeling is that 't' is perhaps not a commonly known/used unit in Europe - I had to look it up (in Wikipedia of course). I wonder what NASA uses in its documents.

Also, have "...produce 1,800,000 lbf (8.0 MN) of thrust..." - imperial then metric. And "...propellant load of up to 285,000 lb (129,000 kg)..." - again imperial them metric. I'm sure it's best to be consistently and primarily metric throughout, and use imperial in parentheses for clarity for US readers. Taliska (talk) 02:43, 9 December 2014 (UTC)

US units are listed first for most measures since they are the primary unit and strong US ties. And yes, tonne is not the proper US term. t is the official symbol on Wikipedia per WP:UNITS. Using '(tonne, t)' as you suggest should be fine. Metric ton is the more common unit for payloads. So that's listed first. -Fnlayson (talk) 03:05, 9 December 2014 (UTC)

EUS engines

Block IB's second stage, scheduled to debut on Exploration Mission 2 (EM-2), will use the 8.4 meter Exploration Upper Stage (EUS), previously named the Dual Use Upper Stage (DUUS), powered by four RL10 engines.

The conceptual design does use the RL10C-1 as a baseline, but the contracts for the EUS engines haven't been awarded yet, and NASA is still evaluating options. So, while it's certain they will have to be similar to the RL10, no engines have been selected as far as I know. -Daydreamers (talk) 15:49, 29 December 2014 (UTC)