Project Mercury also excluded civilian NASA X-15 pilot Neil Armstrong, though he had been selected by the US Air Force in 1958 for its Man In Space Soonest program, which was replaced by Mercury. Although Armstrong had been a combat-experienced NAP during the Korean War, he left active duty in 1952. Armstrong became NASA's first civilian astronaut in 1962 when he was selected for NASA's second group, and became the first man on the Moon in 1969. It was further stipulated that candidates should be between 25 and 40 years old, no taller than , and hold a college degree in a
Neil Armstrong the first manned Moon landing, and spent two and a half hours outside the spacecraft while Michael Collins remained in lunar orbit in the command and service module. When Armstrong stepped onto the lunar surface, he famously said: "That's one small step for [a] man, one giant leap for mankind." Along with Collins and Aldrin, Armstrong was awarded the Presidential Medal of Freedom by President Richard Nixon. President Jimmy Carter presented Armstrong with the Congressional Space Medal of Honor in 1978, and Armstrong and his former crewmates received a Congressional Gold Medal in 2009. After he resigned from NASA in