Apollo Lunar Module propulsion systems. Cutaway illustration of the propulsion systems of the Apollo Lunar Module, the spacecraft used to land astronauts on the surface of the Moon. The Lunar Module consisted of two sections. The descent stage (bottom) allowed a powered landing on the lunar surface, and served as a launch pad for the ascent stage. The ascent stage (top) contained propulsion systems for returning the astronauts to lunar orbit and rendezvous with the orbiting Apollo Command/Service Module. Both stages used rocket engines with Aerozine 50 fuel and dinitrogen tetroxide oxidizer.