Lunar and Planetary Institute

Apollo 10 Mission

Overview | Activities | Photography

Mission Activities

Lunar Module Activation

The checkout proceeded smoothly and was completed in about two hours. The lunar module appeared to be in the same condition as observed during closeout activity before launch. Transfer of stowage items and required housekeeping chores were performed. The transfer from command module to lunar module power was performed without incident. A landmark tracking training exercise was also performed during the checkout period.

Lunar Module Operations
The lunar module testing phase of the mission lasted for more than six hours and involved a number of operations:  the undocking and separation of the lunar module; a series of communications and radar checks; the firing of the descent engine and moving to within 8 miles of the lunar surface; checking the landing radar over one of the selected landings sites; and modifying the orbit in preparation for the return to the command module, staging the lunar module to simulate an ascent from the lunar surface, and performing the rendezvous with the command service module.

Landmark Tracking
This was one of the activities planned for the final day in lunar orbit. Landmark tracking was performed on four landmarks each revolution for four consecutive revolutions. This activity required close coordination between the commander, command module pilot, and the network.

All detailed test objectives were satisfied with the exception of the lunar module steerable antenna and relay modes for voice and telemetry communications. Problems with the steerable antenna test objective were due to the track mode not being switched properly. The communication relay modes test objectives were not demonstrated due to a lack of time rather than any problems.


This mission was the “dress rehearsal” for the first lunar landing. Apollo 10 entered orbit around the Moon and the lunar module was separated from the spacecraft to descend to within 9 miles of the lunar surface with two astronauts on board. The astronauts tested the lunar module’s radar and ascent engine and surveyed the landing site for Apollo 11. The lunar module was then returned to orbit where the crew successfully performed all required rendezvous maneuvers. The mission also served as a test of the extensive new Apollo tracking and control network on Earth. Spacecraft systems performance was satisfactory and all mission objectives were accomplished.