Fifty years ago this month, the Apollo Lunar Module (LM) was flown by an astronaut crew in space for the first time during the Apollo 9 earth-orbital mission. This technological achievement was critical to the success of the first lunar landing mission which occurred a little over 4 months later.
The Apollo Lunar Module (LM) was the world’s first true spacecraft in that it was designed to operate in vacuum conditions only. It was the third and final element of the Apollo spacecraft; the first two elements being the Command Module (CM) and the Service Module (LM).
The LM had its own propulsion, life-support and GNC systems. The vehicle weighed about 33,000 lbs on Earth and was used to transport a pair of astronauts from lunar orbit to the lunar surface and back into lunar orbit.
The spacecraft was really a two-stage vehicle; a descent stage and an ascent stage weighing 23,000 lbs and 10,000 lbs on Earth, respectively. The thrust of descent stage rocket motor could be throttled and produced a maximum thrust of 10,000 lbs while the ascent stage rocket motor was rated at 3,500 lbs of thrust.
On Monday, 03 March 1969, Apollo 9 was rocketed into earth-orbit by the mighty Saturn V launch vehicle. The primary purpose of this mission was to put the first LM through its paces by astronauts preparatory to the first lunar landing attempt.
During the 10-day mission, the crew of Commander James A. McDivitt, CM Pilot David R. Scott and LM Pilot Russell L. “Rusty” Schweickart fully verified all moon landing-specific operational aspects (short of an actual landing) of the LM. Key orbital activities included multiple-firings of both LM rocket motors and several rendezvous and docking exercises in which the LM flew as far away as 113 miles from the CM-SM pair.
By the time the crew splashed-down in the Atlantic Ocean on Thursday, 13 March 1969, America had a new operational spacecraft and a fighting chance to land men on the moon and safely return them to the Earth before the end of the decade.