Gemini 2

• Also called Gemini-Titan 2

• Launched January 19, 1965 at 14:03:59 UTC; landed January 19, 1965 at 14:22:15 UTC

• No crew.

• Orbital mass: 3133.9 kg

This was the second uncrewed Gemini test mission, consisting of a sub-orbital ballistic flight and reentry with the primary objectives being to demonstrate the adequacy of the spacecraft reentry module's heat protection during a maximum heating rate return, the structural integrity of the spacecraft, and the performance of spacecraft systems. Secondary objectives included obtaining test results on communications, cryogenics, fuel cell and reactant supply system, and further qualification of the launch vehicle.

The flight was launched successfully from complex 19 to a maximum altitude of 171.2 km. The spacecraft was run by an onboard automatic sequencer. At 6 minutes 54 seconds after launch, retrorockets were fired and the spacecraft cartwheeled into a reentry attitude. The spacecraft reentered the atmosphere and landed by parachute in the Atlantic Ocean 3419 km southeast of the launch site 18 minutes 16 seconds after launch. The landing was 26 km short of the planned impact point. The spacecraft was successfully recovered by the aircraft carrier U.S.S. Lake Champlain, which was 84 km from the splashdown point, at 15:52 UT. All goals were achieved except test results on the fuel cells because the system had failed before liftoff and was turned off. The capsule was in excellent condition and the heat shield and retrorockets functioned as planned. The temperature in the cooling system of the spacecraft was found to be too high.

Gemini 5

• Launched August 21, 1965 at 13:59:59 UTC; landed August 29, 1965 at 12:55:13 UTC

• Crew: Gordon Cooper and Charles "Pete" Conrad

• Orbital mass: 3605 kg

Gemini 5 was the third crewed Earth-orbiting spacecraft of the Gemini series. The flight was designed to last eight days and test rendezvous procedures. The major objectives of this mission were to demonstrate a long-duration crewed flight, evaluate the effects of long periods of weightlessness on the crew, and test rendezvous capabilities and maneuvers using a rendezvous evaluation pod. Secondary objectives included demonstration of all phases of guidance and control systems to support rendezvous and controlled reentry guidance, to evaluate the fuel cell power system and rendezvous radar, to test the capability of either pilot to maneuver the spacecraft in orbit to close proximity with another object, and to conduct 17 experiments.

Gemini 5 was launched from Complex 19 and inserted into a 162.0x350.1 km Earth orbit at 14:05:55. The rendezvous evaluation pod (REP), a 34.5 kg optical and electronic duplicate of the Agena planned for use in later Gemini rendezvous missions was deployed two hours into the flight on the second revolution. About 36 minutes into the evaluation of the rendezvous system, the crew noticed the pressure in the oxygen supply tank of the fuel cell system was dropping. At some point earlier in the flight the oxygen supply heater element had failed, and the pressure dropped from nominal pressure of 850 psia to a low of 65 psia 4 hours and 22 minutes into the flight. This was still above the 22.2 psia minimum but it was decided to cancel the REP exercise and power the spacecraft down. An analysis was carried out on the ground and a powering up procedure was started on the seventh revolution. Over the rest of the mission the pressure slowly rose in the fuel cells and sufficient power was available at all times.

Four rendezvous radar tests were conducted during the mission, starting on revolution 14 on the second day. On the third day, a simulated rendezvous with a phantom Agena was conducted. On day five, thruster number 7 became inoperative and maneuvering system operation became sluggish. Thruster number 8 failed the next day and the system became increasingly erratic. Limited experimental and operational activities continued throughout the remainder of the mission. Retrofire was made on revolution 120 (one revolution early due to a threatening tropical storm near the landing area) at 12:27:42 UTC on August 29. Splashdown occurred in the western Atlantic at 29.73° N, 69.75° W after a total mission time of 190:55:14. Splashdown was 169 km short of the target due to a ground-based computer program error. The crew arrived onboard the aircraft carrier U.S.S. Lake Champlain at 9:26 and the spacecraft was recovered at 16:50.

All objectives were achieved except rendezvous with the REP and pilot tests associated with the rendezvous and the demonstration of controlled reentry to a predetermined landing point. Scientific studies included zodiacal light, synoptic terrain, synoptic weather photography, and a cloud top spectrometer experiment. In addition, five medical and seven technological experiments were performed during the mission. One photography experiment was cancelled because of cancellation of the rendezvous maneuver. The mission demonstrated human ability to adapt to weightlessness over an extended period and then readapt to normal gravity and was considered successful.