Alan Bean was selected by NASA as part of Astronaut Group 3 in 1963 (after not being selected for Astronaut Group 2 the previous year). He was selected to be the backup Command Pilot for Gemini 10 but was unsuccessful in securing an early Apollo flight assignment. He was placed in the Apollo Applications Program in the interim. In that capacity, he is the first astronaut to dive in the Neutral Buoyancy Simulator and a champion of the process for astronaut training. When fellow astronaut Clifton Williams was killed in an air crash, a space was opened for Bean on the back-up crew for Apollo 9. Apollo 12 Commander Conrad, who had instructed Bean at the Naval Flight Test School years before, personally requested Bean to replace Williams.
Alan Bean was the lunar module pilot on Apollo 12, the second lunar landing. In November 1969, Al Bean and Pete Conrad landed in the Moon's Ocean of Storms—after a flight of 250,000 miles and a launch that included a harrowing lightning strike. Bean was the astronaut who executed John Aaron's famous "Flight, try SCE to 'Aux'" instruction to restore telemetry after the spacecraft was struck by lightning 36 seconds after launch, thus salvaging the mission. They explored the lunar surface, deployed several lunar surface experiments, and installed the first nuclear power generator station on the Moon to provide the power source. Dick Gordon remained in lunar orbit photographing landing sites for future missions.