Apollo Lunar Module

Apollo Lunar Module

Apollo 14 Lunar Module Antares on the Moon's surface, February 1971
Manufacturer	Grumman
Designer	Thomas J. Kelly
Country of origin	United States
Operator	NASA
Applications	Crewed lunar landing
Specifications
Spacecraft type	Lunar lander
Launch mass	33,500 lb (15,200 kg) standard 36,200 lb (16,400 kg) extended
Dry mass	9,430 lb (4,280 kg) standard 10,850 lb (4,920 kg) extended
Crew capacity	2
Volume	235 cu ft (6.7 m3)
Power	28 V DC, 115 V 400 Hz AC
Batteries	Six or seven 28–32-volt, 296 ampere hour silver-zinc
Regime	Lunar orbit Lunar landing
Design life	75 hours (extended)
Dimensions
Length	23 ft 1 in (7.04 m)
Diameter	13 ft 10 in (4.22 m) without landing gear
Width	31 ft (9.4 m), landing gear deployed
Production
Status	Retired
Built	15
Launched	10
Operational	10
Retired	1972
Failed	0
Lost	0
Maiden launch	January 22, 1968
Last launch	December 7, 1972
Last retirement	December 14, 1972
Related spacecraft
Flown with	Apollo Command and Service Module
Configuration

The Apollo Lunar Module (LM /ˈlɛm/), originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed spacecraft to operate exclusively in the airless vacuum of space, and remains the only crewed vehicle to land anywhere beyond Earth.

Structurally and aerodynamically incapable of flight through Earth's atmosphere, the two-stage Lunar Module was ferried to lunar orbit attached to the Apollo command and service module (CSM), about twice its mass. Its crew of two flew the Lunar Module from lunar orbit to the Moon's surface. During takeoff, the spent descent stage was used as a launch pad for the ascent stage which then flew back to the command module, after which it was also discarded.

Overseen by Grumman, the LM's development was plagued with problems that delayed its first uncrewed flight by about ten months and its first crewed flight by about three months. Regardless, the LM became the most reliable component of the Apollo–Saturn space vehicle.^[1] The total cost of the LM for development and the units produced was $21.65 billion in 2016 dollars, adjusting from a nominal total of $2.29 billion^[2] using the NASA New Start Inflation Indices.^[3]

Ten lunar modules were launched into space. Of these, six were landed by humans on the Moon from 1969 to 1972. The first two flown were tests in low Earth orbit: Apollo 5, without a crew; and Apollo 9 with a crew. A third test flight in low lunar orbit was Apollo 10, a dress rehearsal for the first landing, conducted on Apollo 11. The Apollo 13 lunar module functioned as a lifeboat to provide life support and propulsion to keep the crew alive for the trip home, when their CSM was disabled by an oxygen tank explosion en route to the Moon.

The six landed descent stages remain at their landing sites; their corresponding ascent stages crashed into the Moon following use. One ascent stage (Apollo 10's Snoopy) was discarded in a heliocentric orbit after its descent stage was discarded in lunar orbit.^[4] The other three LMs were destroyed during controlled re-entry in the Earth's atmosphere: the four stages of Apollo 5 and Apollo 9 each re-entered separately, while Apollo 13's Aquarius re-entered as a unit.