The crew assignments for Gemini 8 were announced on September 20 , 1965 . Under the normal rotation system , the backup crew for one mission became the prime crew for the third mission after , but Slayton designated David Scott as the pilot of Gemini 8 . Scott was the first member of the third group of astronauts , whose selection was announced on October 18 , 1963 , to receive a prime crew assignment . See was designated to command Gemini 9 . Henceforth , each Gemini mission was commanded by a member of Armstrong 's group , with a member of Scott 's group as the pilot . Conrad would be Armstrong 's backup this time , and Richard F. Gordon Jr. his pilot . Armstrong became the first American civilian in space . ( Valentina Tereshkova of the Soviet Union had become the first civilian — and first woman — nearly three years earlier aboard Vostok 6 when it launched on June 16 , 1963 . ) Armstrong would also be the last of his group to fly in space , as See died in a T-38 crash on February 28 , 1966 , that also took the life of crewmate Charles Bassett . They were replaced by the backup crew of Tom Stafford and Gene Cernan , while Jim Lovell and Buzz Aldrin moved up from the backup crew of Gemini 10 to become the backup for Gemini 9 , and would eventually fly Gemini 12
T-38 crash
1966 NASA T-38 crash
Neil Armstrong