Astronaut Edward White performs the first American spacewalk during Gemini 4's third orbit. He remained outside the vehicle for
21 minutes.
Gemini VI Astronauts Schirra and Stafford rendezvous with the Gemini VII spacecraft.
Gemini VI Astronauts Schirra and Stafford rendezvous with the Gemini VII spacecraft.
Astronauts Frank Borman and James Lovell await recovery after completing the 14-day Gemini VII mission.
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The Gemini Program was conceived after it became evident to NASA officials that an intermediate step was required between Project Mercury and the Apollo Program. The major objectives assigned to Gemini were to:
- subject two men and supporting equipment to long-duration flights — a requirement for the moon landing
- effect rendezvous and docking with other orbiting vehicles, and maneuver the docked vehicles in space, using the propulsion system of the target vehicle for such maneuvers
- perfect methods of reentry and landing the spacecraft at a pre-selected ground-landing point
- gain additional information concerning the effects of weightlessness on crew members and record the physiological reactions of crew members during long-duration flights.
There were a total of ten manned flights in the program. All major program objectives were met as well as additional ones assigned to each mission, with the exception of a land landing, which was canceled in 1964. However, the precision control necessary for such a task was demonstrated.
The Gemini spacecraft was an enlargement of the previous Mercury capsule. It accommodated a two-person crew, measuring 19 ft long and 10 ft in diameter. The Titan II rocket, more powerful than the Redstone, was chosen for the program.
Gemini III, which was the first manned Gemini mission launched March 23, 1965, was commanded by Grissom, a veteran from Project Mercury, and piloted by John Young. The mission was to demonstrate the two-man design, tracking network, Orbital Attitude and Maneuvering System (OAMS) capability in orbital maneuvers and in retrofire backup, and controlled reentry and landing. All of these objectives were achieved except that of controlled reentry; the angle of attack was lower than expected.
The next mission in the program was to evaluate the effects of prolonged space flight, spacecraft performance, and systems. The flight, which was commanded by James McDivitt and piloted by Edward White, achieved all but one of the primary objectives. The computer-controlled reentry in the demonstration and evaluation of spacecraft systems objective was not conducted because of inadvertent alteration of computer memory. Secondary objectives included demonstrating and evaluating EVA and control by use of a hand-held maneuvering unit (HHMU) and tether; stationkeeping and rendezvous with second stage of the Gemini Launch Vehicle (GLV); evaluating space systems; performing in-and-out plane maneuvers; and further testing of OAMS retro backup capability. All of these were performed successfully except for separation and rendezvous, which could not be attempted due to unexpectedly high fuel consumption. However, the first EVA, which lasted 36 minutes, was carried out successfully by White, demonstrating that an astronaut, with the aid of a space suit, could survive outside the capsule.
Gemini V, commanded by veteran astronaut Gordon Cooper and piloted by Charles Conrad, was to demonstrate and evaluate the use of the rendezvous guidance and navigation system, fuel cell technology, and controlled reentry guidance. During the mission, fuel cell problems precluded rendezvous with the radar evaluation pod. Controlled reentry guidance was also not achieved due to incorrect navigation coordinates transmitted to the spacecraft computer from the ground, causing an 89-mi overshoot of the landing zone.
The next critical objective of the program was rendezvous and docking. When the Gemini VI Agena target vehicle used for rendezvous and docking failed, Gemini VII, commanded by Frank Borman and piloted by James Lovell, was used for rendezvous instead. Gemini VI-A, commanded by Walter Schirra and piloted by Thomas Stafford, performed a closed-loop rendezvous in fourth orbit with Gemini VII. Station-keeping with Gemini 7 lasted for over five hours at distances ranging from 1 to 295 ft. This was the first rendezvous between two U.S. spacecraft, demonstrating another task necessary for landing on the moon.
Gemini VIII involved not only rendezvous with another spacecraft, but docking as well. This mission, commanded by Neil Armstrong and piloted by David Scott, resulted in the docking of the Gemini VIII spacecraft with the Agena target vehicle 6 h and 34 min. after liftoff. A malfunction caused uncontrollable spinning of the two spacecraft while docked. The combination of the two had begun to encounter increasing yaw and roll rates, forcing the crew to undock after approximately 30 minutes. Control of the spacecraft was regained by using the reentry control system, which prompted an early landing in a secondary landing area in the Pacific.
Another docking mission followed in which the original Agena target vehicle failed to orbit. Instead the Gemini IX spacecraft, commanded by Thomas Stafford and piloted by Eugene Cernan, was to rendezvous and dock with the augmented target docking adapter (ATDA). However, the ATDA shroud failed to jettison, preventing the docking from occurring. Gemini IX was able to perform a number of rendezvous maneuvers, including a simulation of lunar module rendezvous.
Gemini X, flown by John Young and Michael Collins, rendezvoused and docked with the Gemini Agena target vehicle. The Agena's propulsion system was used for the first time during the docking maneuver. The same maneuver was performed by Charles Conrad and Richard Gordon to achieve high-apogee excursion during the Gemini XI mission. A record altitude of 739.2 mi was accomplished.
The last mission of the program, Gemini XII, involved another docking with a target vehicle. More importantly, the mission was used to learn more about enhancing EVA skills and capabilities. This would provide NASA with more information on how to adequately train its astronauts for the longer and more frequent EVAs that would be conducted on the moon. This was important because it increased the astronauts' productivity in a zero-g environment, allowing for more experiments and data to be collected during their limited time in space and on the moon. Astronaut Buzz Aldrin set an EVA record of 5 h and 30 min. for one space walk and two stand-up exercises.
The Gemini missions allowed NASA to validate concepts and technologies under development for the Apollo program. By better understanding these concepts and technologies through demonstration, engineers would be able to improve their designs, ensuring a higher probability of success. The missions also provided astronauts with the opportunity to learn and enhance their EVA, rendezvous, and docking skills.
