Since there would have been a large gap between the end of Project Mercury and the Apollo flights, NASA opted to develop Project Gemini, which would give the US much needed experience in space. The beginnings of Gemini go back to February of 1961. On 7 December 1961, it was introduced as Mercury Mark II, and renamed Project Gemini on 3 January 1962. In Latin, "gemini" means "twins" or "side by side". As with Mercury, the craft was developed and built by McDonnell. The Titan II ICBM (Martin Marietta) was selected as the launch vehicle.
Project Gemini Objectives:
- To subject men and equipment to long duration space flight (to the moon).
- To gain information on the physical and psychological effects of long duration weightlessness.
- To develop rendezvous and docking procedures.
- To perfect methods of reentry and landing.
Project Gemini cost about USD 1.28 billion in 1966 (over USD 7 billion in 2010).
Gemini 1 - 8-12 April 1964. This was a 4 day/64 orbit test. The "mission" was terminated after 3 orbits, although the spacecraft continued in orbit for another 3.5 days before disintegrating. There was no planned re-entry or recovery. The purpose of the flight was to test structural integrity.
Gemini 2 - 19 January 1965. This was an 18 minute suborbital test of the re-entry and recovery systems. The capsule was refurbished and the heat shield modified with a hatch as a Gemini B mockup test for the USAF MOL program. It was launched by a Titan IIIC for a 33 minute suborbital flight on 3 November 1966. Gemini 2 can be found at the Air Force Space and Missile Museum, Cape Canaveral Air Force Station, FL.
The Gemini capsule was redesigned for use with the Manned Orbiting Laboratory. This craft was designed to be shut down for orbital storage, had the seats relocated to allow access to a hatch cut into the heat shield (to allow entry into the MOL), and had a larger heat shield to handle high energy re-entry from polar orbit. Changes were also made in instrumentation, number and location of thrusters, and the atmosphere (Helium/Oxygen mix). Gemini B was intended for use with the MOL and thus was not capable of independent operation for longer than 14 hours.
There were early proposals to use the Gemini capsule for lunar missions. Lunar missions would have been much more cost efficient using Gemini. It is estimated that a lunar orbit could have been achieved 3 years earlier using a Gemini craft, and that a manned landing could have occurred a year earlier than Apollo 11. The trip would have been quite uncomfortable using the Gemini due to the cramped quarters. Another factor dooming a lunar flight for Gemini was that Project Apollo was well underway and NASA had its mind set on a three man mission, not two.