Claim: Neil Armstrong was an astronaut on Gemini 8.

Gemini 8 -LRB- officially Gemini VIII -RRB- was the sixth manned spaceflight in NASA 's Gemini program . The mission conducted the first docking of two spacecraft in orbit , but suffered the first critical in-space system failure of a U.S. spacecraft which threatened the lives of the astronauts and required immediate abort of the mission . The crew was returned to Earth safely . The only other time this happened was on the flight of Apollo 13 .   It was the twelfth manned American flight and the twenty-second manned spaceflight of all time -LRB- including X-15 flights over 100 km -RRB- . Command pilot Neil Armstrong 's flight marked the second time a U.S. civilian flew into space -LRB- Joseph Albert Walker became the first U.S. civilian on X-15 Flight 90 -RRB- . Armstrong had resigned his commission in the United States Naval Reserve in 1960 . The Soviet Union had launched the first civilian , Valentina Tereshkova -LRB- also the first woman -RRB- , aboard Vostok 6 on June 16 , 1963 .