Gemini 5

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Gemini V
View of Cape Canaveral, Florida from Gemini V
Operator NASA
COSPAR ID 1965-068A[1]
SATCAT № 1516[2]
Mission duration 7 days, 22 hours, 55 minutes, 14 seconds
Distance travelled 5,242,682 kilometers (3,257,652 miles)
Orbits completed 120
Spacecraft properties
Spacecraft Gemini SC5
Manufacturer McDonnell
Launch mass 3,605 kilograms (7,948 lb)
Crew size 2
Members L. Gordon Cooper, Jr.
Charles "Pete" Conrad, Jr.
Start of mission
Launch date August 21, 1965, 13:59:59 (1965-08-21UTC13:59:59Z) UTC
Rocket Titan II GLV, s/n 62-12560
Launch site Cape Canaveral LC-19
End of mission
Landing date August 29, 1965, 12:55:13 (1965-08-29UTC12:55:14Z) UTC
Landing site 29°47′N 69°45.4′W / 29.783°N 69.7567°W / 29.783; -69.7567 (Gemini 5 splashdown)
Orbital parameters
Reference system Geocentric
Regime Low Earth orbit
Perigee 170 kilometers (92 nautical miles)
Apogee 330 kilometers (180 nautical miles)
Inclination 32.5 degrees
Period 89.5 minutes
Epoch August 23, 1965[2]

Gemini5insignia.png S65-46990.jpg
(L-R) Conrad, Cooper

Project Gemini
← Gemini 4 Gemini 7

Gemini 5 (officially Gemini V)[3] was a 1965 manned spaceflight in NASA's Gemini program. It was the third manned Gemini flight, the 11th manned American flight and the 19th spaceflight of all time (includes X-15 flights over 100 kilometers (54 nmi)). It was also the first time an American manned space mission held the world record for duration, set on August 26, 1965, by breaking the Soviet Union's previous record set by Vostok 5 in 1963.[4]


Position Astronaut
Command Pilot L. Gordon Cooper, Jr.
Second and last spaceflight
Pilot Charles "Pete" Conrad, Jr.
First spaceflight

Backup crew[edit]

Position Astronaut
Command Pilot Neil A. Armstrong
Pilot Elliot M. See, Jr.

Support crew[edit]

Mission parameters[edit]

  • 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.


Gemini 5 doubled the U.S space-flight record of the Gemini 4 mission to eight days, the length of time it would take to fly to the Moon, land and return. This was possible due to new fuel cells that generated enough electricity to power longer missions, a pivotal innovation for future Apollo flights. Cooper and Conrad were to have made a practice space rendezvous with a "pod" deployed from the spacecraft, but problems with the electrical supply forced a switch to a simpler "phantom rendezvous," whereby the Gemini craft maneuvered to a predetermined position in space. Command Pilot and Mercury veteran Gordon Cooper was the first person to fly two Earth orbital missions. He and Conrad took high-resolution photographs for the United States Department of Defense, 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 REP
REP Radar Evaluation Pod
NSSDC ID: 1965-068C
Mass 34.5 kilograms (76 lb)
Launch date August 21, 1965
Release time 16:07:15 UTC
Perigee 162 kilometers (87 nmi)
Apogee 350.1 kilometers (189.0 nmi)
Period 89.59 min
Inclination 32.61°
Reentered August 27, 1965

Conrad, who had a reputation for frequently having a punchline on hand, called the mission "Eight days in a garbage can." (the garbage can referring to the small size of the Gemini cabin, which was about the size of the front seat of a Volkswagen Beetle.)


The erector at Pad 19 is lowered in preparation for the launch of Gemini 5

The launch was perfect except for a few seconds of pogo (axial oscillation of the rocket). This was measured at +0.38 g (3.7 m/s²) during first stage 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 kilometers.

Gemini 5 Radar Evaluation Pod (REP)

The first major event on the mission was the ejection of the Radar Evaluation Pod (REP) 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, the crew found that the pressure in the fuel cell had dropped from 850 to 65 pounds per square inch (5,860 to 450 kPa) 4 hours and 22 minutes into the flight. This was still above the 22.2 psi (153 kPa) minimum but Cooper decided to shut it down. Without power they would be unable to rendezvous with the REP, and it could also 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. Stars slowly drifting by the windows also proved disorienting, so the crew put covers on the windows.

Gemini 5 fuel cell assembly

As with Gemini 4, the crew had trouble sleeping in 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 crew discovered a small problem the next day. The fuel cell produced waste water (not suitable for drinking, as it was too acidic) that was stored in a tank on board. This was the same tank used for drinking water, with the potable and non-potable water separated by a bladder wall. The problem was that the fuel cell was producing 20% more discharge than expected. However, it was soon determined that there would still be room left over at the end of the mission.

On the fifth day, a relatively major problem occurred when one of thrusters in the OAMS stopped working. This meant the cancellation of all the experiments requiring fuel. None of the attempts to resolve the thruster problem was successful.

Gordon Cooper being hoisted into the recovery helicopter

Seventeen experiments were planned, with one cancelled, as it involved photography of the REP. Experiment D-1 involved the crew photographing celestial objects, and D-6 was a ground photography experiment. Experiments D-4/D-7 involved making brightness measurements of celestial and terrestrial backgrounds and of rocket plumes. Experiments S-8/D-13 investigated whether the crew's eyesight changed during the mission.

All the medical experiments from Gemini 4 were performed, as well as experiment M-1 into the performance of the heart. This involved Conrad wearing inflatable leg cuffs. Experiment M-9 also investigated whether the astronauts' ability to measure horizontally changed.

S-1 involved Cooper taking the first photographs of the zodiacal light and the gegenschein from orbit. There was also syntopic photography of Earth. One photograph of the Zagros Mountains revealed greater detail than the official geologic map of Iran. Experiment S-7, the Cloud-Top Spectrometer revealed that the height of clouds could be determined from orbit.

Retrofire came 190 hours, 27 minutes, and 43 seconds into the mission over Hawaii. The astronauts controlled the reentry, creating drag and lift by rotating the capsule. Due to a computing error, the crew landed 130 kilometers short of the planned landing point in the Atlantic Ocean. Though the computer had worked perfectly, a programmer 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. Recovery was by USS Lake Champlain.


Gemini 5 Flown Silver Fliteline Medallion

This was the first mission to have an insignia patch. After Gemini 3, NASA barred astronauts from naming their spacecraft. Cooper, having realized he had never been in a military organization without one, suggested a mission patch to symbolize the flight. NASA agreed, and the patches got the generic name of "Cooper patch."[5] Cooper chose the image of a covered wagon due to the pioneering nature of the flight. The slogan "8 Days or Bust" was emblazoned across the wagon, but NASA managers objected to this, feeling it placed too much emphasis on the mission length and not the experiments, and fearing the public might see the mission as a failure if it did not last the full duration. A piece of nylon cloth was sewn over the slogan.[6]

Spacecraft location[edit]

As of 2006, the spacecraft is on display at Space Center Houston, Houston, Texas.

See also[edit]

The first stage of the Titan II rocket used to launch Gemini 5 is recovered by USS DuPont


 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

  1. ^ "NSSDC Master Catalog: Gemini 5". NASA. Retrieved September 4, 2013. 
  2. ^ a b "Satellite Catalog". Retrieved September 4, 2013. 
  3. ^ Hacker, Barton C.; Grimwood, James M. (September 1974). "Chapter 11 Pillars of Confidence". On the Shoulders of Titans: A History of Project Gemini. NASA History Series. SP-4203. NASA. p. 239.  With Gemini IV, NASA changed to Roman numerals for Gemini mission designations.
  4. ^ Sehlstedt, Albert "Gemini Nears Soviet Space Flight Mark" (August 26, 1965) The Baltimore Sun, p. 1
  5. ^ Cooper, Gordon; Bruce Henderson (2002). Leap of Faith: An Astronaut's Journey into the Unknown. HarperTorch. p. 320. ISBN 978-0-06-109877-2. 
  6. ^ French, Francis; Colin Burgess (2007). In the Shadow of the Moon. University of Nebraska Press. p. 44. ISBN 978-0-8032-1128-5. 

External links[edit]