The Apollo Lunar Module (LM), previously known as the Lunar Excursion Module (LEM), was the lander portion of the Apollo spacecrafl built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back. Six such craft successfully landed on the Moon between 1969 to 1972. The LM, consisting of an ascent stage and descent stage, was ferried to lunar orbit by its companion Command/Service Module (CSM), a separate spacecraft of approximately fwice its mass, which also took the astronauta home to Earth.