The Command/Service Module was one of the two spacecraft that were utilized for the Apollo program, along with the Lunar Module, to land astronauts on the Moon. Together they were called the Apollo spacecraft.
The Command Module (reentry capsule, CM-107 callsign Columbia) housed the crew and the equipment needed for re-entry and splashdown.
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The Service Module (SM-107) provided propulsion, electrical power and storage for various consumables required during a mission. It would be cast off and allowed to burn up in the atmosphere before the command module re-entered and brought the crew home.
The Apollo Lunar Module Eagle was the lander portion of the Apollo spacecraft built to achieve the transit from cislunar orbit to the surface and back.
The S-IVB served as the third stage on the Saturn V and second stage on the Saturn IB. It had one J-2 engine. For lunar missions it was fired twice: first for the orbit insertion after second stage cutoff, and then for translunar injection.
Two liquid-fueled Auxiliary Propulsion System units mounted at the aft end of the stage were used for attitude control during the parking orbit and the trans-lunar phases of the mission.
