The Lunar Module (LM) was the craft that carried two of the three astronauts from the Command Module (CM) in orbit around the Moon to the lunar surface and back. It was comprised of two stages: an ascent stage and a descent stage. The ascent stage contained the LM controls and living quarters for the astronauts. During launch, the LM sat inside the Lunar Module Adapter (SLA), nestled between the third stage of the Saturn V launch vehicle and the Service Module. After attaining orbit around the Moon, the LM detached from the CM and the descent stage booster guided the LM’s landing on the Moon’s surface. When lunar surface activities were completed, the ascent stage used the descent stage as a launch platform to rendezvous with the CM in lunar orbit. After the lunar-landing party returned to the Command Module, the LM was jettisoned. Fifteen LMs were built by Grumman Aircraft, but only 10 were used in flight, with six of those landing astronauts on the Moon.