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 was co-sponsored by NASA. After he returned from Seattle on June 4, he applied to become an astronaut. His application arrived about a week past the June 1, 1962, deadline, but Dick Day, a flight simulator expert with whom Armstrong had worked closely at Edwards, saw the late arrival of the application and slipped it into the pile before anyone noticed. At Brooks Air Force Base at the end of June, Armstrong underwent a medical exam that many of the applicants described as painful and at times seemingly pointless. NASA's Director of Flight Crew Operations, Deke Slayton, called Armstrong on