Project Gemini

Project Gemini was the second human spaceflight program in which the United States of America sent humans into space, between Projects Mercury and Apollo, during the years 1963-1966. Its objective was to develop techniques for advanced space travel, notably those necessary for Apollo, whose objective was to land men on the Moon. Gemini missions involved extravehicular activity and orbital maneuvers including rendezvous and docking.

Related Topics:
Human spaceflight - United States of America - Mercury - Apollo - 1963 - 1966 - Moon - Extravehicular activity - Rendezvous - Docking

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Gemini was originally seen as a simple extrapolation of the Mercury program, and thus early on was called Mercury Mark II. The final program had little in common with Mercury and was in fact superior to even Apollo in some ways. (See Big Gemini.) This was mainly a result of its late start date, which allowed it to benefit from much that had been learned by that time on the Apollo project (which, despite its later launch dates, was actually begun before Gemini).

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Its primary difference from Mercury was that the earlier spacecraft had all systems other than the reentry rockets sited within the capsule, nearly all of which had to be accessed through the astronaut's hatchway, while Gemini had many power, propulsion, and life-support systems in a detachable module like a huge bowl; many components in the capsule itself were reachable each through its own small access door. The original intention was for Gemini to use a paraglider instead of a parachute, and the crew to be seated upright controlling the forward motion of the craft before its landing. To facilitate this, the parachute cord does not just attach to the nose of the craft; there is an additional attachment point for balance near the heat shield. This cord is covered by a strip of metal between the doors. Early, short-duration missions had their electrical power supplied by batteries; later endurance missions had the first fuel cells in manned spacecraft.

Related Topics:
Paraglider - Fuel cell

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The "Gemini" designation comes from the fact that each spacecraft held two men, as "gemini" in Latin means "twins". Gemini is also the name of the third constellation of the Zodiac and its twin stars, Castor and Pollux.

Related Topics:
Gemini - Zodiac - Castor - Pollux

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Unlike Mercury, which could only change its orientation in space, the Gemini capsule could alter its own orbit. It could also dock with other spacecraft--one of which, the Agena Target Vehicle, had its own large rocket engine which was used to perform large orbital changes. Gemini was the first American manned spacecraft to include an onboard computer, the Gemini Guidance Computer, to facilitate management and control of mission maneuvers.

Related Topics:
Agena Target Vehicle - Gemini Guidance Computer

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The main contractor was McDonnell who had lost out on main contracts for the Apollo Project. McDonnell sought to extend the programme by proposing a Gemini craft could be used to fly a cislunar mission and even achieve a manned lunar landing earlier and at less cost than Apollo but these were rejected.

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The Gemini program cost $5.4 billion in 1994 dollars. See NASA Budget.

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