Apollo 10 Mission Patch
Apollo 10 was the fourth manned mission in the United States Apollo space program. It was an F type mission—its purpose was to be a dress rehearsal 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 nautical miles (15.6 km) of the lunar surface during practice maneuvers.
Apollo 10 was the first of only two Apollo missions with an entirely flight-experienced crew. Thomas P. Stafford had flown on Gemini 6 and Gemini 9; John W. Young had flown on Gemini 3 and Gemini 10, and Eugene A. Cernan had flown with Stafford on Gemini 9. In addition, Apollo 10 marked the only Saturn V flight from Launch Complex 39B, as preparations for Apollo 11 at LC-39A had begun in March almost immediately after Apollo 9's launch.