High Quality Content by WIKIPEDIA articles! Apollo 10 was the fourth manned mission in the American Apollo space program. It was an F type mission—its purpose was to be a "dry run" for the Apollo 11 mission, testing all of the procedures and components of a Moon landing without actually landing on the Moon itself. The mission included the second crew to orbit the Moon and an all-up test of the lunar module (LM) in lunar orbit. The LM came to within 8.4 mi (13.5 km) of the lunar surface during practice maneuvers.