A participant in the U.S. Air Force's Man InSpace Soonest and X-20 Dyna-Soar human spaceflight programs, Armstrong joined the NASA Astronaut Corps in 1962. His first spaceflight was the NASA Gemini 8 mission in1966, for which he was the command pilot, becoming one of the first U.S. civilians in space. On this mission, he performed the first manned docking of two spacecraft withpilot David Scott.
Armstrong's second and last spaceflight was as mission commander of the Apollo 11 moon landing in July 1969. On this mission, Armstrong and Buzz Aldrindescended to the lunar surface and spent 2½ hours exploring, while Michael Collins remained in orbit in the Command Module. Armstrong was awarded the Presidential Medalof Freedom by President Richard Nixon along with Collins and Aldrin, the Congressional Space Medal of Honor by President Jimmy Carter in 1978, and the CongressionalGold Medal with his former crewmates in 2009.
Armstrong died in Cincinnati, Ohio, on August 25, 2012, at the age of 82 due to complications from blocked coronary arteries.