The Apollo Lunar Module (LM) was a two-stage vehicle designed to ferry two astronauts from lunar orbit to the lunar surface and back. The upper ascent stage consisted of a pressurized crew compartment, equipment areas, and an ascent rocket engine. The lower descent stage had the landing gear and contained the descent rocket engine and lunar surface experiments.

LM 9 was to have flown on Apollo 15 with astronauts David Scott and James Irwin. However, when NASA decided that Apollo 15 and subsequent flights would be outfitted with lunar roving vehicles, LM 9 was replaced with LM 10, a version modified to carry the Lunar Rover. NASA transferred ownership of LM 9 to the Smithsonian in March 1973.