The Apollo program sent nine expeditions to the Moon. Six landed 12 astronauts on the lunar surface, starting July 20, 1969. North American developed the conical command module, where the crew rode; a cylindrical service module; and the service propulsion system. The last Apollo Moon mission was Dec. 7 to 19, 1972. Three Apollo command and service modules were used on the Skylab program, and the last Apollo mission was in July 1975, for the Apollo-Soyuz test project.