Lunar excursion module

Apollo 16 - LEM "Orion" nach dem Abkoppeln zur Mondlandung
Apollo 16 - LEM “Orion” after uncoupling for moon-landing

the lunar excursion module (- LM for lunar modules, or also - LEM for lunar Excursion of modules) is starting from 1963 a spacecraft developed by the company Grumman for NASA in the context of the Apollo project for landingon the moon. The Vorplanungen of NASA decrease/go back however already in the year 1960 . Altogether 16 pieces were manufactured.


Table of contents

work on] general

around

humans on the moon to bring, there were 7 the most diverse scenarios, which were durchdacht in the early phase of the Apollo project. Relatively fast NASA of one came completely on the moonlanding spacecraft, to a divided system, with which an astronaut in the “return cap” circles around the moon and is a separate “landing vehicle ” with two astronauts to the Mondexkursion to be used.

development

Entwicklung der Landefähre zwischen 1962 und 1969
development of the landing ferry between 1962 and 1969
Lunar Modul - Mondlandefähre
lunar module - lunar excursion module
Übungslandefähre 1964 auf der Edwards Air Force Base
Exercise landing ferry 1964 on the Edwards' air Force cousin

in the year 1963 was issued then the order for the building of the landing ferry to the company Grumman in Bethpage, New York. Thomas's J. Kelly, which already accompanied the early studies for the development of the LM, becomes generallythe father of the landing ferry calls. As he however said, the LM was a Gemeinschaftsproduktion of many. For example also the future Apollo astronauts were involved in the development and construction, since they had to finally fly and land the LM. This Scott Carpenter was main, Charles Conrad, and Donn Eisele.

The LM was the largest manned spacecraft, which was ever developed and built to therefore. For two astronauts place had to be enough available, around the LM evt inside the landing ferry. to fly and land also manually(this should happen in standing). The passengers had to be able themselves to take on and also to space suit off again. Besides also still area for the bring along soil samples (moon rock) had to be present. The moreover one sleep possibilities had to be given for the astronauts.

There the LM alone toMoon descended, must have it also its own life support system and an independently working electrical connection. The companies, which received the addition for the development of these components, were others, than those, which were responsible for the Apollo command and service unit. With the Apollo 13 mission placed itself thatas fatal errors out, since both systems were partly incompatible. Nevertheless also the astronauts could return from Apollo 13 to the earth, in which they were after the explosion in the service unit a longer time in the still functional LM. The LM served here as it were asLife raft.

The landing legs represented a special problem. They should be like that grazil and easily as possible, in addition, as stably as necessary, for a landing on the moon. In addition they had to be hinged, there the transport of the LM in a rocket stage already relatively earlyone specified. At the beginning of planning the developers planned five landing legs. From space reasons however only four were then realized, which did however no abort to condition stability. For reaching the lunar surface a landing leg got a mounted ladder.

But the probably largest problem, itself, was the impossibility resulted in the flight characteristics of the LM in the terrestrial atmosphere to be tested. It should be tried to copy the moon gravitation as by means of additional engines a lift should be given to the countries. Since lift and Steuerdüsen affected each other however mutually, the countries fell usually laterally.Also tests also at helicopters hung up countries did not bring usable results. Thus to purposes of practice flight tests with landing racks, the LLTVs were accomplished. A special construction was the LLRF for practicing the last landing sequence up to putting on.

During the start, two and a half ground orbits and the capital invested inthe Mondbahn stayed the landing ferry in the third stage of the Saturn V and after separation of the Apollo of spaceship and its to 180° turn out of it was then taken. The total combination flew then to the moon.

a total weight

of 14.696 had technical data the landing ferrykg, a height of 6,40m and a diameter of 4.30m (9,50m with driven out landing legs). It consisted of over one million parts, had redundantly laid out radio and radar device, several engines and a computer. The lunar excursion module was developed on the basis of purely functional criteria. Aerodynamics did not playRole. The system consisted of 2 stages: the descent stage (the cent of steam turbine and gas turbine systems - DS) and the ascent stage (Ascent of steam turbine and gas turbine systems - AS), of which everyone was equipped with a master engine.

descent stage (DS)

the descent stage was the lower part and contained beside the engine thoseTank for fuel, oxygen, water and helium. Far ones the 4 landing legs and equipment for the external missions. The landing legs gave the vehicle a spider-like appearance, which registered with the astronauts also the pointed name “Spider” to it. The stage was including the landing legs 3.24 mhighly. At the leg, which was under the hatch, was attached a ladder. After conclusion the descent stage served the mission as starting basis for the ascent stage. A blowing up mechanism separated the two stages, whereby the descent stage finally stayed on the moon. If necessary the separation could also during the phase of descent to be accomplished, around the abort for a landing possible with safe return to the Apollo spaceship (CSM) too make.

the four tanks

, two each needed engine of the descent stage most place in the descent stage for the fuel and the oxidizer as well asthe descent engine. This was tiltable and supplied a thrust performance of 10.000 lbs. The achievement of the engine could be throttled by the computer or manually on 1050 lbs. All engines on board used a mixture from 50% hydrazine ( math N_2H_4< /math>)< and> 50% asymmetrical Dimethylhydrazin as fuel, called Aerozin 50. In connection with the oxidizer nitrogen tetroxide (<math> N_2O_4< /math>) is highly explosive the mixture and hypergol, ignites thus with contact independently with one another, without which an ignition system was used. A further tank contained helium of which than propulsion gas the oxidizer and the fuel inthe combustion chamber pressed.

ascent stage (AS)

engine of the ascent stage

the ascent stage contained the cab for two astronauts, a middle section with all controls and the ascending rubbing work. In order to save weight, the two astronauts had to stand with the landing. They became from beltsin their position held. In the front floor area, between the astronauts, was a hatch of approximately 1 m diameter, which was used after the landing to the door. In the central section were a large part the steering and communication as well as of the pressure systems. Here also those becameRock samples for the Rücktranport accommodated. A further hatch of approximately 84 cm diameters was attached in the upper range of the middle section. This hatch was the connection between the landing ferry and the command module.

engine of the ascent stage

the engine for the kind of moving of the moonproduced only a thrust of 3.500 Pound and could only twice be started. That was to be carried sufficiently around the 4.5 tons heavy ascent stage back into the moon orbit. The control during the descent and reclimb phase was accomplished by a computer. A manual control was howeverlikewise possible. The situation of the lunar excursion module in the area was controlled by 16 Steuerdüsen, which were arranged in four groups.

moon car

Apollo 15 was in the context of the Apollo project first of the 3 J-missions so mentioned, the one longer stay on thatMoon planned. A battery-operated moon car (close. Lunar Roving Vehicle), which was attached to transport folded up at the exterior of the lunar excursion module, permitted it, to move more freely over the lunar surface and to investigate a larger area.

climatic system

the climatic system of the lunar excursion module was alsodenRaumanzügen der Astronauten so weit kompatibel, dass sie an der Fähre bis zu sechsmal wieder aufgeladen werden konnten.


history of the 16 lunar excursion modules


No. Name Apollo The whereabouts of the LEM
01 - 5 in terrestrial atmosphere glows
02 - - Smithsonian national air andSpace museum
03 Spider 9 in terrestrial atmosphere glows
04 Snoopy 10 in sun orbit (ascent stage)
05 Eagle 11 Moon (descent stage)
06 Intrepid 12 Moon (descent stage)
07 Aquarius 13 in terrestrial atmosphere glows
08 Antares 14 Moon (descent stage)
09 - - John F. Kennedy space center
10 Falcon 15 Moon (descent stage)
11 Orion 16 Moon (descent stage)
12 Challenger 17 Moon (descent stage)
13 - - The Cradle OF aviation museum
14 - - Franklin of institutes, Philadelphia
15 - - destroys
16 - - Museum OF Science and Industry

LM-2 was for an unmanned testin the earth orbit intended. Due to the success of LM-1 without this test one did. LM-9 was intended for a moon flight, which had been supposed to take place between Apollo 14 and Apollo 15, which were painted however from cost reasons. For Apollo 15 LM-10 was used, a longer duration of stopovermade possible, and a moon car to carry could. When further Apollo flights were called off, LM-13 to LM-16 already was in the building. LM-15 was scrapped by Grumman.

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