Gemini was the US manned space project designed to bridge the gap between the simple techniques and technologies of Mercury and the high-tech hardware and software required for Apollo. Whereas the Mercury capsule was designed for a single astronaut, the Gemini (meaning 'Twins') was designed for two. It also had an opening hatch to permit spacewalking, a Gemini objective. Other major objectives were to practise in-orbit manoeuvring, rendezvousing and docking with other spacecraft, and investigate the effects of weightlessness on astronauts on lengthy missions. All of these objectives would need to be met if Apollo was to be a success. The ten manned Gemini flights began with Gemini 3 in March 1965 and ended with Gemini 12 in November 1966. All the spacecraft were launched by Titan rockets. Making his space debut on Gemini 3 was John Young, beginning an outstanding career that spanned the Gemini, Apollo and shuttle eras of space flight. On Gemini 4 (June 1965) Edward White pioneered spacewalking for the US. First Gemini 5 (August 1965), then Gemini 7 smashed space-duration records, the latter remaining in orbit for two weeks. Gemini 8 (March 1966) saw the first space docking, and the first flight by Neil Armstrong, destined three years later to be the first to set foot on the Moon. Further successful dockings and spacewalks followed on subsequent flights. Highlight of the final mission, Gemini 12 (November 1966), was a 51-hour spacewalk by Edwin Aldrin, later to be Armstrong's partner on the first Moon landing. With all Gemini mission objectives well and truly achieved, the scene was set for Apollo and the final sprint for the Moon.
