The Gemini astronauts were sixteen pilots who flew in Project Gemini, NASA's second human spaceflight program, between projects Mercury and Apollo. Carrying two astronauts at a time, a senior command pilot and a junior pilot, the Gemini spacecraft was used for ten crewed missions. Four of the sixteen astronauts flew twice.[1][2]
Gemini was the second phase in the United States space program's larger goal of "landing a man on the Moon and returning him safely to the Earth" before the end of the 1960s, as proposed by president John F. Kennedy. As an intermediary step, Gemini afforded its astronauts the opportunity to gain critical spaceflight experience, performing tasks required in the later Apollo program which fulfilled this objective. Such tasks included rendezvous or station-keeping with other craft, docking, habitation in space over the course of several days, and flying spacecraft with more than one crew member. Importantly, most individuals who flew as Gemini astronauts returned to space as key personnel in the Apollo program, bringing with them their first-hand experience of the operations carried out during Gemini. Among the Gemini astronauts, six later walked on the Moon, another five flew to the Moon without landing, and two participated in Low Earth orbit Apollo missions. Gus Grissom and Ed White were killed in the Apollo 1 disaster, and former Mercury astronaut Gordon Cooper did not perform any further spaceflights.
Later flew to the Moon as an Apollo astronaut, without landing
Later flew a low-Earth orbit mission as an Apollo astronaut
Performed no later spaceflights
Later killed in the Apollo 1 disaster
Notes
^Sixteen astronauts filled twenty crew positions, over ten two-man missions. Young, Conrad, Lovell and Stafford each made their first spaceflights as junior Pilots before being promoted to Command Pilots on the program's last four missions.
^Armstrong had served in the US Navy and United States Navy Reserve from 1949 to 1960, but was retired from active duty when he became a NASA astronaut.[4]