Gemini 5 - Flight

Flight

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 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.

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 (5,900 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.

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 wastewater (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.

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 43 seconds into the mission over Hawaii. They 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.