NASA's Gemini programme started in 1962 shortly after president Kennedy announced the United States' plan to land astronauts on the Moon. The missions were an important step in achieving this goal.
Gemini engineers and scientists studied the effects of longer spaceflights on astronauts and their equipment and practiced docking spacecraft in orbit and landing. The Gemini spacecraft carried two astronauts - an improvement on the single-seat Mercury capsules used to take the first Americans into space.
Manned Gemini flights started in 1965 and there were 10 in total.
Photo: Ed White makes the first US spacewalk during Gemini 4 (NASA/James McDivitt)
Astronauts and engineers prepare for manned Moon landings.
Apollo 13's Jim Lovell and his fellow astronauts tell James Burke how it was done.
Jim Lovell and his fellow astronauts tell the BBC's James Burke what happened when nature called during the Apollo and Gemini missions.
Aldrin exited the Gemini 12 capsule in 1966.
Buzz Aldrin describes what it was like to leave the Gemini 12 capsule while orbiting above the Earth in 1966, three years before he set foot on the Moon.
Astronaut Jim Lovell describes returning to the Earth.
Before the 1969 Apollo 11 Moon landing, astronaut Jim Lovell describes what it was like to return to the Earth in a space capsule. Lovell flew into space aboard Gemini 7 and 12 and Apollo 8 and 13.
Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966.
Its objective was to develop space travel techniques in support of Apollo, which had the goal of landing men on the Moon. Gemini achieved missions long enough for a trip to the Moon and back, perfected extra-vehicular activity (working outside a spacecraft), and orbital maneuvers necessary to achieve rendezvous and docking. All manned Gemini flights were launched from Cape Canaveral, Florida using the Titan II Gemini launch vehicle ("GLV").