Apollo Lunar Module

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Apollo Lunar Module
Apollo 16 LM Orion on the lunar surface
Manufacturer Grumman Aircraft
Designer Thomas J. Kelly
Country of originUnited States
Operator NASA
ApplicationsCrewed lunar landing
Design life75 hours (Extended)
Launch mass
  • 33,500 pounds (15,200 kg) std
  • 36,200 pounds (16,400 kg) Extended
Dry mass
  • 9,430 pounds (4,280 kg) std
  • 10,850 pounds (4,920 kg) Extended
Crew capacity2
Volume235 cubic feet (6.7 m3)
Power28 V DC, 115 V 400 Hz AC
Batteriestwo 28–32-volt, 296 ampere-hour silver-zinc
Regime Lunar
Length23 feet 1 inch (7.04 m)
Diameter13 feet 10 inches (4.22 m) without landing gear
Width31 feet (9.4 m), landing gear deployed
Maiden launchJanuary 22, 1968
Last launchDecember 14, 1972
Last retirementDecember 15, 1972
Apollo program.svg
Apollo LM diagram

The Apollo Lunar Module, or simply lunar module (LM, pronounced "lem"), originally designated the Lunar Excursion Module (LEM), was the lander spacecraft that was flown from lunar orbit to the Moon's surface during the U.S. 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 complete 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 Aircraft, 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. Still, the LM became the most reliable component of the Apollo/Saturn space vehicle, the only component never to suffer a failure that could not be corrected in time to prevent abort of a landing mission. [1] The total cost of the LM for development and the units produced was $21.3 billion in 2016 dollars, adjusting from a nominal total of $2.2 billion [2] using the NASA New Start Inflation Indices. [3]

Ten lunar modules were launched into space. Of these, six landed humans on the Moon from 1969 to 1972. The first two launched were test flights in low Earth orbit—the first without a crew, the second with one. Another was used by Apollo 10 for a dress rehearsal flight in low lunar orbit, without landing. One lunar module functioned as a lifeboat for the crew of Apollo 13, providing life support and propulsion when their CSM was disabled by an oxygen tank explosion en route to the Moon, forcing the crew to abandon plans for landing.

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. The other three LMs were burned up 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 complete, following emergency maneuvers.

Operational profile

At launch, the lunar module sat directly beneath the command and service module (CSM) with legs folded, inside the Spacecraft-to-LM adapter (SLA) attached to the S-IVB third stage of the Saturn V rocket. There it remained through Earth parking orbit and the trans-lunar injection (TLI) rocket burn to send the craft toward the Moon.

Soon after TLI, the SLA opened; the CSM separated, turned around, came back to dock with the lunar module, and extracted it from the S-IVB. During the flight to the Moon, the docking hatches were opened and the lunar module pilot entered the LM to temporarily power up and test all systems except propulsion. The lunar module pilot performed the role of an engineering officer, monitoring the systems of both spacecraft.

After achieving a lunar parking orbit, the commander and LM pilot entered and powered up the LM, replaced the hatches and docking equipment, unfolded and locked its landing legs, and separated from the CSM, flying independently. The commander operated the flight controls and engine throttle, while the lunar module pilot operated other spacecraft systems and kept the commander informed about systems status and navigational information. After the command module pilot visually inspected the landing gear, the LM was withdrawn to a safe distance, then rotated until the descent engine was pointed forward into the direction of travel. A 30-second descent orbit insertion burn was performed to reduce speed and drop the LM's perilune to within about 50,000 feet (15 km) of the surface, [4] about 260 nautical miles (480 km) uprange of the landing site.

Eagle, the lunar module ascent stage of Apollo 11, in orbit above the Moon. Earth is visible in the distance. Photograph by Michael Collins. Earth, Moon and Lunar Module, AS11-44-6643.jpg
Eagle, the lunar module ascent stage of Apollo 11, in orbit above the Moon. Earth is visible in the distance. Photograph by Michael Collins.

As the craft approached perilune, the engine was started again to begin powered descent. During this time, the crew flew on their backs, depending on the computer to slow the craft's forward and vertical velocity to near zero. Control was exercised with a combination of engine throttling and attitude thrusters, guided by the computer with the aid of landing radar. During braking, the LM descended to about 10,000 feet (3.0 km), then, in the final approach phase, down to about 700 feet (210 m). During final approach, the vehicle pitched over to a near-vertical position, allowing the crew to look forward and down to see the lunar surface for the first time. [5]

Astronauts flew Apollo spacecraft manually only during the lunar approach. [6] The final landing phase began about 2,000 feet (0.61 km) uprange of the targeted landing site. At this point, manual control was enabled for the commander, who had enough propellant to hover for up to two minutes to survey where the computer was taking the craft and make any necessary corrections. If necessary, landing could have been aborted at almost any time by jettisoning the descent stage and firing the ascent engine to climb back into orbit for an emergency return to the CSM. Finally, one or more of three 67.2-inch (1.71 m) probes extending from footpads on the legs of the lander touched the surface, activating the contact indicator light which signaled the commander to manually shut off the descent engine, allowing the LM to settle onto the surface. On touchdown, the probes would be bent as much as 180 degrees, or even break off. The original design used the probes on all four legs, but starting with the first landing (LM-5 on Apollo 11), the one at the ladder was removed out of concern that the bent probe after landing might puncture an astronaut's suit as he descended or stepped off the ladder.

The original extravehicular activity (EVA) plan, up through at least 1966, was for only one astronaut to leave the LM while the other remained inside "to maintain communications". [7] Communications were eventually deemed to be reliable enough to allow both crew members to walk on the surface, leaving the spacecraft to be only remotely attended by Mission Control.

Beginning with Apollo 14, extra LM propellant was made available for the powered descent and landing, by using the CSM engine to achieve the 50,000-foot (15 km) perilune. After the spacecraft undocked, the CSM raised and circularized its orbit for the remainder of the mission.

When ready to leave the Moon, the LM's ascent engine fired, leaving the descent stage on the Moon's surface. After a few course correction burns, the LM rendezvoused with the CSM and docked to transfer the crew and rock samples. Having completed its job, the ascent stage was separated. The Apollo 10 ascent stage engine was fired until its fuel was used up, sending it past the Moon into a heliocentric orbit. [8] [9] The Apollo 11 ascent stage was left in lunar orbit to eventually crash; all subsequent ascent stages (except for Apollo 13) were intentionally steered into the Moon to obtain readings from seismometers placed on the surface.


A 1962 model of the first LEM design, docked to the command and service module. The model is held by Joseph Shea, the key engineer behind the adoption of lunar orbit rendezvous mission logistics. Joseph Francis Shea.jpg
A 1962 model of the first LEM design, docked to the command and service module. The model is held by Joseph Shea, the key engineer behind the adoption of lunar orbit rendezvous mission logistics.

The lunar module (originally designated the lunar excursion module, known by the acronym LEM) was designed after NASA chose to reach the Moon via Lunar Orbit Rendezvous (LOR) instead of the direct ascent or Earth Orbit Rendezvous (EOR) methods. Both direct ascent and EOR would have involved landing a much heavier, complete Apollo spacecraft on the Moon. Once the decision had been made to proceed using LOR, it became necessary to produce a separate craft capable of reaching the lunar surface and ascending back to lunar orbit.

Contract letting

In July 1962, eleven firms were invited to submit proposals for the LEM. Nine companies responded in September, answering 20 questions posed by the NASA RFP in a 60-page limited technical proposal. Grumman Aircraft was awarded the contract two months later. Grumman had begun lunar orbit rendezvous studies in the late 1950s and again in 1961. The contract cost was expected to be around $350 million. There were initially four major subcontractors: Bell Aerosystems (ascent engine), Hamilton Standard (environmental control systems), Marquardt (reaction control system) and TRW's Space Technology Laboratories (descent engine). [10]

The Primary Guidance, Navigation and Control System (PGNCS) was developed by the MIT Instrumentation Laboratory; the Apollo Guidance Computer was manufactured by Raytheon (a similar guidance system was used in the command module). A backup navigation tool, the Abort Guidance System (AGS), was developed by TRW.

Design phase

This 1963 model depicts the second LEM design, which gave rise to informal references as "the bug". Lunar Lander Model.jpg
This 1963 model depicts the second LEM design, which gave rise to informal references as "the bug".

The Apollo Lunar Module was chiefly designed by Grumman aerospace engineer Thomas J. Kelly. [11] The first LEM design looked like a smaller version of the Apollo command and service module (a cone-shaped cabin atop a cylindrical propulsion section) with folding legs. The second design invoked the idea of a helicopter cockpit with large curved windows and seats, to improve the astronauts' visibility for hover and landing. This also included a second, forward docking port, allowing the LEM crew to take an active role in docking with the CSM.

As the program continued, there were numerous redesigns to save weight, improve safety, and fix problems. First to go were the heavy cockpit windows and the seats; the astronauts would stand while flying the LEM, supported by a cable and pulley system, with smaller triangular windows giving them sufficient visibility of the landing site. Later, the redundant forward docking port was removed, which meant the Command Pilot gave up active control of the docking to the Command Module Pilot; he could still see the approaching CSM through a small overhead window. Egress while wearing bulky Extra-Vehicular Activity (EVA) spacesuits was eased by a simpler forward hatch (32 x 32 inches).

The configuration was frozen in April 1963, when the ascent and descent engine designs were decided. In addition to Rocketdyne, a parallel program for the descent engine was ordered from Space Technology Laboratories (TRW) in July 1963, and by January 1965 the Rocketdyne contract was canceled.

Power was initially to be produced by fuel cells built by Pratt and Whitney similar to the CSM, but in March 1965 these were discarded in favor of an all-battery design. [12]

The initial design had three landing legs, the lightest possible configuration. But as any particular leg would have to carry the weight of the vehicle if it landed at a significant angle, this was also the least stable configuration if one of the legs were damaged during landing. The next landing gear design iteration had five legs and was the most stable configuration for landing on an unknown terrain. That configuration, however, was too heavy and the designers compromised on four landing legs. [13]

In June 1966, the name was changed to lunar module (LM), eliminating the word "excursion". [14] [15] According to George Low, Manager of the Apollo Spacecraft Program Office, this was because NASA was afraid that the word "excursion" might lend a frivolous note to Apollo. [16] After the name change from "LEM" to "LM", the pronunciation of the abbreviation did not change, as the habit became ingrained among engineers, the astronauts, and the media to universally pronounce "LM" as "lem" which is easier than saying the letters individually.

Astronaut training

Lunar Landing Research Vehicle (LLRV) during a test flight Lunar Landing Research Vehicle in Flight - GPN-2000-000215.jpg
Lunar Landing Research Vehicle (LLRV) during a test flight

To allow astronauts to learn lunar landing techniques, NASA contracted Bell Aerosystems in 1964 to build the Lunar Landing Research Vehicle (LLRV), which used a gimbal-mounted vertical jet engine to counter five-sixths of its weight to simulate the Moon's gravity, in addition to its own hydrogen peroxide thrusters to simulate the LM's descent engine and attitude control. Successful testing of two LLRV prototypes at the Dryden Flight Research Center led in 1966 to three production Lunar Landing Training Vehicles (LLTV) which along with the LLRV's were used to train the astronauts at the Houston Manned Spacecraft Center. This aircraft proved fairly dangerous to fly, as three of the five were destroyed in crashes. It was equipped with a rocket-powered ejection seat, so in each case the pilot survived, including the first man to walk on the Moon, Neil Armstrong. [17]

Development flights

The Apollo 6 Lunar Module Test Article (LTA-2R) shortly before being mated with the SLA 67-H-1230 Lunar module LTA-2 R.jpg
The Apollo 6 Lunar Module Test Article (LTA-2R) shortly before being mated with the SLA

LM-1 was built to make the first uncrewed flight for propulsion systems testing, launched into low Earth orbit atop a Saturn IB. This was originally planned for April 1967, to be followed by the first crewed flight later that year. But the LM's development problems had been underestimated, and LM-1's flight was delayed until January 22, 1968, as Apollo 5. At that time, LM-2 was held in reserve in case the LM-1 flight failed, which did not happen.

LM-3 now became the first crewed LM, again to be flown in low Earth orbit to test all the systems, and practice the separation, rendezvous, and docking planned for Apollo 8 in December 1968. But again, last-minute problems delayed its flight until Apollo 9 on March 3, 1969. A second, higher Earth orbit crewed practice flight had been planned to follow LM-3, but this was canceled to keep the program timeline on track.

Apollo 10 launched on May 18, 1969, using LM-4 for a "dress rehearsal" for the lunar landing, practicing all phases of the mission except powered descent initiation through takeoff. The LM descended to 47,400 feet (9.0 mi; 14.4 km) above the lunar surface, then jettisoned the descent stage and used its ascent engine to return to the CSM. [18]

Production flights

The first crewed lunar landing occurred on July 20, 1969, in the Apollo 11 LM Eagle. Four days later, the Apollo 11 crew in the Command Module Columbia splashed down in the Pacific Ocean, completing President John F. Kennedy's goal: "...before this decade is out, of landing a man on the Moon and returning him safely to the Earth".

This was followed by landings by Apollo 12 (Intrepid) and Apollo 14 (Antares).

The Apollo 11 lunar module Eagle in lunar orbit Apollo 11 Lunar Module Eagle in landing configuration in lunar orbit from the Command and Service Module Columbia.jpg
The Apollo 11 lunar module Eagle in lunar orbit

In April 1970, the Apollo 13 lunar module Aquarius played an unexpected role in saving the lives of the three astronauts after an oxygen tank in the service module ruptured, disabling the CSM. Aquarius served as a "lifeboat" for the astronauts during their return to Earth. Its descent stage engine was used to replace the crippled CSM Service Propulsion System engine, and its batteries supplied power for the trip home and recharged the Command Module's batteries critical for reentry. The astronauts splashed down safely on April 17, 1970. The LM's systems, designed to support two astronauts for 45 hours (including twice depressurization and repressurization causing loss of oxygen supply), actually stretched to support three astronauts for 90 hours (without depressurization and repressurization and loss of oxygen supply).

Hover times were maximized on the last four landing missions by using the Service Module engine to perform the initial descent orbit insertion burn 22 hours before the LM separated from the CSM, a practice begun on Apollo 14. This meant that the complete spacecraft, including the CSM, orbited the Moon with a 9.1-nautical-mile (16.9 km) perilune, enabling the LM to begin its powered descent from that altitude with a full load of descent stage propellant, leaving more reserve propellant for the final approach. The CSM would then raise its perilune back to the normal 60 nautical miles (110 km). [19]

Extended J-class missions

Decreased clearance led to buckling of the extended descent engine nozzle on the landing of Apollo 15 Apollo 15 Engine Bell.jpg
Decreased clearance led to buckling of the extended descent engine nozzle on the landing of Apollo 15

The extended lunar module (ELM) used on the final three "J-class missions"Apollo 15, 16, and 17 — was upgraded to land larger payloads and stay longer on the lunar surface. The descent engine thrust was increased by the addition of a 10-inch (250 mm) extension to the engine bell, and the descent propellant tanks were enlarged. A waste storage tank was added to the descent stage, with plumbing from the ascent stage. These upgrades allowed stays of up to 75 hours on the Moon.

The Lunar Roving Vehicle was folded up and carried in Quadrant 1 of the descent stage. It was deployed by the astronauts after landing, allowing them to explore large areas and return a greater variety of lunar samples.


Lunar module diagram Lunar Module diagram.jpg
Lunar module diagram
Lunar module crew cabin Apollo Lunar Module Inside View.jpg
Lunar module crew cabin
Astronaut rest (sleeping) accommodation Apollo LM crew rest positions.jpg
Astronaut rest (sleeping) accommodation
Lunar module cutaway illustration LM illustration 02.jpg
Lunar module cutaway illustration

Weights given here are an average for the original pre-ELM spec vehicles. For specific weights for each mission, see the individual mission articles.

Ascent stage

The ascent stage contained the crew cabin with instrument panels and flight controls. It contained its own Ascent Propulsion System (APS) engine and two hypergolic propellant tanks for return to lunar orbit and rendezvous with the Apollo command and service module. It also contained a Reaction Control System (RCS) for attitude and translation control, which consisted of sixteen hypergolic thrusters similar to those used on the Service Module, mounted in four quads, with their own propellant supply. A forward EVA hatch provided access to and from the lunar surface, while an overhead hatch and docking port provided access to and from the Command Module.

Internal equipment included an environmental control (life support) system; a VHF communications system with two antennas for communication with the Command Module; a unified S-band system and steerable parabolic dish antenna for communication with Earth; an EVA antenna resembling a miniature parasol which relayed communications from antennas on the astronauts' Portable Life Support Systems through the LM; primary (PGNCS) and backup (AGS) guidance and navigation systems; an Alignment Optical Telescope for visually determining the spacecraft orientation; rendezvous radar with its own steerable dish antenna; and an ice sublimation system for active thermal control. Electrical storage batteries, cooling water, and breathing oxygen were stored in amounts sufficient for a lunar surface stay of 48 hours initially, extended to 75 hours for the later missions.

During rest periods while parked on the Moon, the crew would sleep on hammocks slung crosswise in the cabin.

The return payload included the lunar rock and soil samples collected by the crew (as much as 238 pounds (108 kg) on Apollo 17), plus their exposed photographic film.

Descent stage

Scale model of the Apollo Lunar Module at the Euro Space Center in Belgium Scale model of the Apollo Lunar Module.jpg
Scale model of the Apollo Lunar Module at the Euro Space Center in Belgium
The Lunar Module Eagle is portrayed on the 2019 United States Apollo 11 50th Anniversary commemorative coins Apollo 11 gold reverse.jpeg
The Lunar Module Eagle is portrayed on the 2019 United States Apollo 11 50th Anniversary commemorative coins

The descent stage's primary job was to support a powered landing and surface extravehicular activity. When the excursion was over, it served as the launch pad for the ascent stage. Its octagonal shape was supported by four folding landing gear legs, and contained a throttleable Descent Propulsion System (DPS) engine with four hypergolic propellant tanks. A continuous-wave Doppler radar antenna was mounted by the engine heat shield on the bottom surface, to send altitude and rate of descent data to the guidance system and pilot display during the landing. Almost all external surfaces, except for the top, platform, ladder, descent engine and heat shield, were covered in amber, dark (reddish) amber, black, silver, and yellow aluminized Kapton foil blankets for thermal insulation. The number 1 (front) landing leg had an attached platform (informally known as the "porch") in front of the ascent stage's EVA hatch and a ladder, which the astronauts used to ascend and descend between the cabin to the surface. The footpad of each landing leg incorporated a 67-inch-long (1.7 m) surface contact sensor probe, which signaled the commander to switch off the descent engine. (The probe was omitted from the number 1 leg of every landing mission, to avoid a suit-puncture hazard to the astronauts, as the probes tended to break off and protrude upwards from the surface.)

Equipment for the lunar exploration was carried in the Modular Equipment Stowage Assembly (MESA), a drawer mounted on a hinged panel dropping out of the lefthand forward compartment. Besides the astronaut's surface excavation tools and sample collection boxes, the MESA contained a television camera with a tripod; as the commander opened the MESA by pulling on a lanyard while descending the ladder, the camera was automatically activated to send the first pictures of the astronauts on the surface back to Earth. A United States flag for the astronauts to erect on the surface was carried in a container mounted on the ladder of each landing mission.

The Early Apollo Surface Experiments Package (EASEP) (later the Apollo Lunar Surface Experiments Package (ALSEP)), was carried in the opposite compartment behind the LM. An external compartment on the right front panel carried a deployable S-band antenna which, when opened looked like an inverted umbrella on a tripod. This was not used on the first landing due to time constraints, and the fact that acceptable communications were being received using the LM's S-band antenna, but was used on Apollo 12 and 14. A hand-pulled Modular Equipment Transporter (MET), similar in appearance to a golf cart, was carried on Apollo 13 and 14 to facilitate carrying the tools and samples on extended moonwalks. On the extended missions (Apollo 15 and later), the antenna and TV camera were mounted on the Lunar Roving Vehicle, which was carried folded up and mounted on an external panel. Compartments also contained replacement Portable Life Support System (PLSS) batteries and extra lithium hydroxide canisters on the extended missions.

Lunar modules produced

Serial numberNameUseLaunch dateLocationImage
LTA-1Unflown Cradle of Aviation Museum [21]
LTA-2R Apollo 6 April 4, 1968Reentered Earth's atmosphere 67-H-1230 Lunar module LTA-2 R.jpg
LTA-3AUnflown Kansas Cosmosphere and Space Center [21]
LTA-3DRUnflown descent stage Franklin Institute [21] Apollo lander, Franklin Institute - DSC06612.JPG
LTA-5DUnflownNASA White Sands Test Facility [21]
LTA-8A [21] Lunar Module Test Article no.8 Thermal-vacuum tests Ground tests in 1968 Space Center Houston [21]


LTA-10R Apollo 4 November 9, 1967Reentered Earth's atmosphere [21]
MSC-16Non-flight ascent stage Museum of Science & Industry [21]
TM-5Non-flight Museum of Life and Science [21]
PA-1Unflown White Sands Test Facility [21]
LM-1 Apollo 5 January 22, 1968Reentered Earth's atmosphere Lm1 ground.jpg
LM-2Intended for second uncrewed flight, used instead for ground testing. Landing gear added for drop testing. Lacks optical alignment telescope and flight computer [22]
On display at the National Air and Space Museum, Washington, DC LunarLander.JPG
LM-3Spider Apollo 9 March 3, 1969Descent and ascent stages reentered Earth's atmosphere separately Spider Over The Ocean - GPN-2000-001109.jpg
LM-4Snoopy Apollo 10 May 18, 1969Descent stage may have hit the Moon, ascent stage in heliocentric orbit. Snoopy is the only surviving flown LM ascent stage. AS10-34-5087.jpg
LM-5Eagle Apollo 11 July 16, 1969Descent stage on lunar surface in Sea of Tranquility, ascent stage left in lunar orbit (orbit decayed: impact location on Moon unknown) Apollo 11 Lunar Lander - 5927 NASA.jpg
LM-6Intrepid Apollo 12 November 14, 1969Descent stage on lunar surface at Ocean of Storms, ascent stage deliberately crashed into Moon Bean Descends Intrepid - GPN-2000-001317.jpg
LM-7Aquarius Apollo 13 April 11, 1970Reentered Earth's atmosphere Apollo 13 Lunar Module.jpg
LM-8Antares Apollo 14 January 31, 1971Descent stage on lunar surface at Fra Mauro, ascent stage deliberately crashed into Moon Antares on the Frau Mauro Highlands - GPN-2000-001144.jpg
LM-9Not flown, intended as Apollo 15, last H-class mission
On display at the Kennedy Space Center (Apollo/Saturn V Center)
LM-10Falcon Apollo 15, first ELMJuly 26, 1971Descent stage on lunar surface at Hadley–Apennine, ascent stage deliberately crashed into Moon Apollo 15 flag, rover, LM, Irwin.jpg
LM-11Orion Apollo 16 April 16, 1972Descent stage on lunar surface at Descartes Highlands, ascent stage left in lunar orbit, crashed on Moon Apollo 16 LM Orion.jpg
LM-12Challenger Apollo 17 December 7, 1972Descent stage on lunar surface at Taurus-Littrow, ascent stage deliberately crashed into Moon Apollo 17 LM Ascent Stage.jpg
Not flown, intended as Apollo 18 [23]
Partially completed by Grumman, restored and on display at Cradle of Aviation Museum, Long Island, New York. Also used during 1998 miniseries From the Earth to the Moon .
Not flown, intended as Apollo 19
Not flown
* For the location of LMs left on the Lunar surface, see list of man-made objects on the Moon.
World map showing locations of Apollo Lunar Modules (along with other hardware). Apollo Spacecraft Locations World Map.png
World map showing locations of Apollo Lunar Modules (along with other hardware).

Proposed derivatives

Apollo Telescope Mount

Original proposed "wet workshop" Skylab with the Apollo Telescope Mount Wet Workshop.svg
Original proposed "wet workshop" Skylab with the Apollo Telescope Mount

One proposed Apollo application was an orbital solar telescope constructed from a surplus LM with its descent engine replaced with a telescope controlled from the ascent stage cabin, the landing legs removed and four "windmill" solar panels extending from the descent stage quadrants. This would have been launched on an uncrewed Saturn 1B, and docked with a crewed command and service module, named the Apollo Telescope Mission (ATM).

This idea was later transferred to the original wet workshop design for the Skylab orbital workshop and renamed the Apollo Telescope Mount to be docked on a side port of the workshop's multiple docking adapter (MDA). When Skylab changed to a "dry workshop" design pre-fabricated on the ground and launched on a Saturn V, the telescope was mounted on a hinged arm and controlled from inside the MDA. Only the octagonal shape of the telescope container, solar panels and the Apollo Telescope Mount name were kept, though there was no longer any association with the LM.

LM Truck

The Apollo LM Truck (also known as Lunar Payload Module) was a stand-alone LM descent stage intended to deliver up to 11,000 pounds (5.0 t) of payload to the Moon for an uncrewed landing. This technique was intended to deliver equipment and supplies to a permanent crewed lunar base. As originally proposed, it would be launched on a Saturn V with a full Apollo crew to accompany it to lunar orbit and guide it to a landing next to the base; then the base crew would unload the "truck" while the orbiting crew returned to Earth. [24] In later AAP plans, the LPM would have been delivered by an uncrewed lunar ferry vehicle.

Depiction in film and television

The 1995 Ron Howard film Apollo 13 , a dramatization of that mission starring Tom Hanks, Kevin Bacon, and Bill Paxton, was filmed using realistic spacecraft interior reconstructions of the Aquarius and the Command Module Odyssey.

The development and construction of the lunar module is dramatized in the 1998 miniseries From the Earth to the Moon episode entitled "Spider". This is in reference to LM-3, used on Apollo 9, which the crew named Spider after its spidery appearance. The unused LM-13 stood in during the teleplay to depict LM-3 and LM-5, Eagle, used by Apollo 11.


See also

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The Constellation Program is a cancelled crewed spaceflight program developed by NASA, the space agency of the United States, from 2005 to 2009. The major goals of the program were "completion of the International Space Station" and a "return to the Moon no later than 2020" with a crewed flight to the planet Mars as the ultimate goal. The program's logo reflected the three stages of the program: the Earth (ISS), the Moon, and finally Mars—while the Mars goal also found expression in the name given to the program's booster rockets: Ares. The technological aims of the program included the regaining of significant astronaut experience beyond low Earth orbit and the development of technologies necessary to enable sustained human presence on other planetary bodies.

Apollo (spacecraft) American spacecraft

The Apollo spacecraft was composed of three parts designed to accomplish the American Apollo program's goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth. The expendable (single-use) spacecraft consisted of a combined command and service module (CSM) and an Apollo Lunar Module (LM). Two additional components complemented the spacecraft stack for space vehicle assembly: a spacecraft–LM adapter (SLA) designed to shield the LM from the aerodynamic stress of launch and to connect the CSM to the Saturn launch vehicle and a launch escape system (LES) to carry the crew in the command module safely away from the launch vehicle in the event of a launch emergency.

Apollo command and service module component of the United States Apollo spacecraft

The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother ship, which carried a crew of three astronauts and the second Apollo spacecraft, the Apollo Lunar Module, to lunar orbit, and brought the astronauts back to Earth. It consisted of two parts: the conical command module, a cabin that housed the crew and carried equipment needed for atmospheric reentry and splashdown; and the cylindrical service module which provided propulsion, electrical power and storage for various consumables required during a mission. An umbilical connection transferred power and consumables between the two modules. Just before reentry of the command module on the return home, the umbilical connection was severed and the service module was cast off and allowed to burn up in the atmosphere.

The Apollo Applications Program (AAP) was created as early as 1966 by NASA headquarters to develop science-based human spaceflight missions using hardware developed for the Apollo program. AAP was the ultimate development of a number of official and unofficial Apollo follow-on projects studied at various NASA labs.. However, the AAP's ambitious initial plans became an early casualty when the Johnson Administration declined to support it adequately, partly in order to implement its Great Society set of domestic programs while remaining within a $100 billion budget. Thus, Fiscal Year 1967 ultimately allocated $80 million to the AAP, compared to NASA's preliminary estimates of $450 million necessary to fund a full-scale AAP program for that year, with over $1 billion being required for FY 1968. The AAP eventually led to Skylab, which absorbed much of what had been developed under Apollo Applications.

Lunar orbit rendezvous Spaceflight maneuver

Lunar orbit rendezvous (LOR) is a key concept for efficiently landing humans on the Moon and returning them to Earth. It was utilized for the Apollo program missions in the 1960s and 1970s. In a LOR mission, a main spacecraft and a smaller lunar lander travel to lunar orbit. The lunar lander then independently descends to the surface of the Moon, while the main spacecraft remains in lunar orbit. After completion of the mission there, the lander returns to lunar orbit to rendezvous and re-dock with the main spacecraft, then is discarded after transfer of crew and payload. Only the main spacecraft returns to Earth.

Journey of Apollo 15 to the Moon

Launched at 9:34:00 am EST on July 26, 1971, Apollo 15 took four days to reach the Moon. After spending two hours in orbit around the Earth, the S-IVB third stage of the Saturn V was reignited to send them to the Moon.

Several planned missions of the Apollo crewed Moon landing program of the 1960s and 1970s were canceled for a variety of reasons, including changes in technical direction, the Apollo 1 fire, hardware delays, and budget limitations. After the landing by Apollo 12, Apollo 20, which would have been the final crewed mission to the Moon, was canceled to allow Skylab to launch as a "dry workshop". The next two missions, Apollos 18 and 19, were later canceled after the Apollo 13 incident and further budget cuts. Two Skylab missions also ended up being canceled. Two complete Saturn Vs ended up going unused and are currently on display in the United States.

Altair (spacecraft) Planned lander spacecraft component of NASAs cancelled Project Constellation

The Altair spacecraft, previously known as the Lunar Surface Access Module or LSAM, was the planned lander spacecraft component of NASA's cancelled Constellation program. Astronauts would have used the spacecraft for landings on the Moon, which was intended to begin around 2019. The Altair spacecraft was planned to be used both for lunar sortie and lunar outpost missions. On February 1, 2010, U.S. President Barack Obama announced a proposal to cancel the Constellation program, to be replaced with a re-scoped program, effective with the U.S. 2011 fiscal year budget.

Manned Venus flyby

Manned Venus Flyby” was a 1967–1968 NASA proposal to send three astronauts on a flyby mission to Venus in an Apollo-derived spacecraft in 1973–1974, using a gravity assist to shorten the return journey to Earth.

Lunar escape systems series of proposed emergency spacecraft for the Apollo Program

Lunar escape systems (LESS) were a series of emergency vehicles designed for never-flown long-duration Apollo missions. Because these missions were even more hypothetical than the planned cancelled Apollo missions, the designs were never constructed. This concept was an outgrowth of the Lunar Flying Vehicle designed by Bell Aerospace.

LK (spacecraft) Soviet lunar lander intended to be used in the Soviet lunar landing attempts.

The LK was a piloted lunar lander developed in the 1960s as a part of the Soviet attempts at human exploration of the Moon. Its role was analogous to the American Apollo Lunar Module (LM). Several LK modules were flown without crew in Earth orbit, but no LK ever reached the Moon. The development of the N1 launch vehicle required for the Moon flight suffered setbacks, and the first Moon landings were achieved by US astronauts. As a result, both the N1 and the LK programs were cancelled without any further development.

Transposition, docking, and extraction

Transposition, docking, and extraction was a maneuver performed during Apollo lunar landing missions from 1969 to 1972, to withdraw the Apollo Lunar Module (LM) from its adapter housing which secured it to the Saturn V launch vehicle upper stage and protected it from the aerodynamic stresses of launch. The maneuver involved the command module pilot separating the Apollo Command and Service Module (CSM) from the adapter, turning the CSM around, and docking its nose to the Lunar Module, then pulling the combined spacecraft away from the upper stage. It was performed shortly after the trans-lunar injection maneuver that placed the Apollo spacecraft on a three-day trajectory to the Moon. The docking created a continuous, pressurized tunnel which permitted the astronauts to transfer internally between the CSM and the LM.

Advanced Gemini is a number of proposals that would have extended the Gemini program by the addition of various missions, including manned low Earth orbit, circumlunar and lunar landing missions. Gemini was the second manned spaceflight program operated by NASA, and consisted of a two-seat spacecraft capable of maneuvering in orbit, docking with unmanned spacecraft such as Agena Target Vehicles, and allowing the crew to perform tethered extra-vehicular activities.


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Further reading