Project Gemini was NASA's second major series of manned spacecraft, the intermediate stage between the groundbreaking Project Mercury, which placed the first American astronauts into space, and the Apollo project, which sent astronauts to the Moon for the first - and, so far, only - time. Gemini missions included the first spacewalks by American astronauts, the first orbital docking maneuvers, and the longest times in space yet by astronauts. Overall, ten manned and two unmanned Gemini spaceflights occurred between 1964 and 1966.
- The Gemini Program -
Gemini had its origins in President John F. Kennedy's decision to send men to the Moon, in 1961. To reach the Moon, NASA realized, it would have to extend its skill set in space considerably farther than that demonstrated in the comparatively primitive Gemini program. Future astronauts would need to live for days or weeks in space, dock with other spacecraft (the command module and the lunar module), and spacewalk. Mercury had attempted none of these.
- Prominent Missions -
The Gemini program was placed under the control of George Mueller at NASA, and a Canadian aerodynamicist which NASA hired after the collapse of the Arrow jet fighter program at Canadian aviation firm Avro, along with a number of other leading engineers from the same company. Although several astronauts from the original Astronaut Group 1 were retained (including Gus Grissom, who tragically lost his life on Apollo 1), NASA also recruited a new group of nine men as part of Astronaut Group 3, including future Apollo leading lights John Young, James Lovell, Neil Armstrong, and Frank Borman, and then a third group (Astronaut Group 3), including Buzz Aldrin, Eugene Cernan, and Michael Collins.
After two test flights in 194 and early 1965, Gemini 3, the first manned Gemini flight, blasted off or March 23, 1965, sending Gus Grissom and John Young into orbit for a brief three-orbit flight. The next flight, Gemini 4, featured the first American spacewalk, a 22-minute excursion by Edward White.
Gemini 7, which for a variety of reasons actually launched the week before Gemini 6, then succeeded in making the first orbital rendezvous (but not actual docking), with the now-ascended Gemini 6. The same craft, flown by Frank Borman and James Lovell, also stayed in orbit for an unprecedented two weeks, confirming that NASA could sustain men in space long enough to make the lengthy trip to the Moon. Originally, NASA had hoped to make its first orbital rendezvous using an unmanned target craft known as Agena, but because of difficulties with Agena, it chose to leap straight to docking two manned craft together. Actual spacecraft docking eventually occurred with Gemini 8, flown by Neil Armstrong.
The final flight, Gemini 12, put these components together in November 1966, with a test docking and spacewalk performed over a nearly four-day flight. At an overall cost of $5.4 billion, the Gemini program achieved ten manned spaceflights without loss, making it a highly successful intermediate step between Mercury and Apollo.
- Spacecraft -
The standard capsule used in the Gemini flights departed from the earlier Mercury spacecraft, introducing the separation of the crew compartment and the rocket and other equipment into separate modules. The total spacecraft also had to be significantly larger, at about 8500 pounds, to support the second onboard crewman. NASA originally considered and then scrapped plans for making Gemini capable of ground landings rather than only splashdowns.
Like the Mercury spacecraft, for Gemini NASA relied upon customized versions of U.S. Air Force nuclear missiles rather than purpose-built launch vehicles. However, it switched from the Atlas missiles used in the later missions of the Mercury program (which originally used Redstone missiles) to the more advanced Titan II missile. Some of the military Titans, after their retirement, were similarly converted for use as launch vehicles for government satellites, between the 1980s and 2003.