Schweickart joined NASA as one of 14 astronauts named in 1963, the third group selected. He served as a lunar module pilot of Apollo 9 which was the first manned flight of the lunar module. On the mission with him were James McDivitt (commander) and David R. Scott (command module pilot). He also served as backup commander for the first Skylab mission in 1973. After the Skylab program he transferred to NASA Headquarters in Washington, D.C..