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Gemini 5

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Gemini 5
Mission Insignia
Gemini 5 Insignia
Mission Statistics
Mission Name: Gemini 5
Call Sign: Gemini 5
Number of
Crew:		 2
Launch: August 21, 1965
13:59:59.518 UTC
Cape Canaveral
LC 19
Landing: August 29, 1965
12:55:13 UTC
29°47′N 69°45.4′W / 29.783°N 69.7567°W / 29.783; -69.7567
Duration: 7 days, 22 hours
55 minutes
14 seconds
Distance Traveled: ~5,242,682 km
Orbits: 120
Apogee:
(1st orbit)		 350.1 km
Perigee:
(1st orbit)		 162 km
Period:
(1st orbit)		 89.59 m
Inclination: 32.61 deg
Mass: 3,605 kg
Crew Picture
Gemini 5 crew portrait (L-R: Conrad, Cooper)
Gemini 5 crew portrait
(L-R: Conrad, Cooper)
Gemini 5 Crew

Gemini 5 (officially Gemini V) was a 1965 manned spaceflight in NASA's Gemini program. It was the 3rd manned Gemini flight, the 11th manned American flight and the 19th spaceflight of all time (includes X-15 flights over 100 km).

Crew

Backup Crew

Mission Parameters

  • REP (Radar Evaluation Pod) sub-satellite:

On August 21, 1965 at 16:07:15 UTC, the REP was released into orbit from the Gemini 5 spacecraft.


See also

Objectives

Gemini V doubled the space-flight record to eight days, thanks to new fuel cells that generated enough electricity to power longer missions. Cooper and Conrad were to have made a practice rendezvous with a "pod" deployed from the spacecraft, but problems with the electricity supply forced a switch to a simpler "phantom rendezvous," whereby the Gemini maneuvered to a predetermined position in space. Mercury veteran Gordon Cooper was the first person to travel on orbital missions twice. He and Conrad took high-resolution photographs for the Defense Department, but problems with the fuel cells and maneuvering system forced the cancellation of several other experiments. The astronauts found themselves marking time in orbit, and Conrad later lamented that he had not brought along a book. On-board medical tests, however, continued to show the feasibility of longer flights.

Gemini 5 doubled the length of the Gemini 4 mission. It was solely a long duration flight, aiming for eight days, the length of time that it would take to fly a mission to the moon. There would also be an attempt to rendezvous with a pod released from the spacecraft. This was also the first mission to carry fuel cells that would be pivotal in any Apollo flight.

Gemini 5 REP
REP Radar Evaluation Pod
NSSDC ID: 1965-068C
Mass 34.5 kg
Launch Date August 21, 1965
Release Time 16:07:15 UTC
Perigee 162 km
Apogee 350.1 km
Period 89.59 m
Inclination 32.61°
Reentered August 27, 1965


Flight

The launch was perfect except for a few seconds of pogo. This was when the rocket had lateral movement. This was measured at +0.38 g (3.7 m/s²) during stage 1 flight, exceeding the permitted +0.25 g (2.5 m/s²) for a total of about 13 seconds. The cause was traced to a pre-launch procedure and pogo never affected another Gemini flight. The initial orbit was 163 by 349 kilometres.

Gemini 5 Radar Evaluation Pod (REP)(NASA)

The first major event on the mission was the ejection of the rendezvous pod at 2 hours and 13 minutes into the flight. The radar showed that the pod was moving a relative speed of two meters per second. While out of radio contact with the ground they found that the pressure in the fuel cell had dropped to from 850 to 65 lbf/in² (5,860 to 450 kPa) 4 hours and 22 minutes into the flight. This was still above the 22.2 lbf/in² (153 kPa) minimum but Cooper decided to shut it down. Without power they would be unable to rendezvous with the pod and it could mean a premature end to the mission.

Tests on the ground found that it was possible for the fuel cell to work, even with low oxygen pressure. However with the fuel cell off, they would only be able to stay in orbit for a day and still have enough battery power for reentry.

It was decided to turn the fuel cells back on and test them by using equipment that required more and more power. These showed that the fuel cells were stable and the crew could continue the mission.

In the meantime, Buzz Aldrin had been working out an alternative rendezvous test. He had a PhD in orbital mechanics and worked out a scheme where the crew could rendezvous with a "point in space".

The crew became cold as they drifted. Even with the coolant pipes in the suits turned off and the airflow on low they still shivered. There was also the annoying fact that stars slowly drifting by the window were disorientating, so the crew put covers on the windows.

Gemini 5 Fuel Cell Assembly (NASA)

As with Gemini 4 they had trouble sleeping with the alternate sleep periods. They still had little rest when they decided to take their sleep periods together.

The phantom rendezvous came on the third day. It went perfectly even though it was the first precision maneuver on a spaceflight. They tried four maneuvers—apogee adjust, phase adjust, plane change, and coelliptical maneuver—using the orbit attitude and maneuvering system (OAMS).

The ground realised that there was a small problem during the next day. The fuel cell produced water, though this was not suitable for drinking as it was too acidic. It was therefore stored on a tank on board. The problem was that this was the same tank as the drinking water, with the two separated by a bladder wall. The problem was that the fuel cell was producing 20% more discharge than expected. However it was soon discovered that there would still be room left over at the end of the mission.

On the fifth day a relatively major problem occurred. One of thrusters in the OAMS stopped working. This meant the cancellation of all the experiments requiring fuel and none of the solutions worked to getting the thrusters to start working again.

Seventeen experiments were planned with one cancelled, as it involved photography of the pod. D-1 involved the crew photographing celestial objects, and D-6 was a ground photography experiment. D-4/D-7 involved making brightness measurements of celestial and terrestrial backgrounds and on rocket plumes. S-8/D-13 was an experiment to investigate whether the crews eyesight changed during the mission.

View of Cape Kennedy, Florida from Gemini 5 (NASA)

All the medical experiments from Gemini 4 were performed as well as M-1 into the performance of the heart. This involved Conrad wearing inflatable leg cuffs. There was also M-9 which investigated whether their ability to measure horizontally changed.

S-1 involved Cooper taking the first photographs of the zodiacal light and the gegenschein from orbit. There were also syntopic photography of Earth. One photograph of the Zagros Mountains showed more detail than the official Geologic Map of Iran. S-7, Cloud-Top Spectrometer found that you could tell the height of cloud from orbit.

Retrofire came 190 hours 27 minutes 43 seconds into the mission over Hawaii. They controlled the reentry, creating drag and lift by rotating the capsule. They still landed 130 kilometers short of the planned landing point. But the computer had worked perfectly, the problem was in the programming. Someone had entered the rate of the Earth's rotation as 360° per 24 hours instead of 360.98° See Sidereal day.

The Gemini 5 mission was supported by the following U.S. Department of Defense resources; 10,265 personnel, 114 aircraft and 19 ships.

Insignia

This was the first mission to have an actual patch. Cooper realised that he had never been in a military organisation that didn't have its own patch. They decided on a covered wagon due to the pioneering nature of the flight. It was also intended to have '8 Days or Bust' across the wagon, but this plan was scuttled by the NASA manangers who feared that if the mission didn't last the full duration, it would be seen as a failure even if it wasn't. It also placed too much emphasis on the mission length and not the experiments. In the end they were 104 minutes short of eight days.

Capsule Location

The capsule is on display at the Lyndon B. Johnson Space Center, Houston, Texas.

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