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The Apollo Lunar Module (LM), originally designated the Lunar Excursion Module (LEM), was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman Aircraft to carry a crew of two from lunar orbit to the surface and back. Designed for lunar orbit rendezvous, it consisted of an ascent stage and descent stage, and was ferried to lunar orbit by its companion Command and Service Module (CSM), a separate spacecraft of approximately twice its mass, which also took the astronauts home to Earth. After completing its mission, the LM was discarded. It was capable of operation only in outer space; structurally and aerodynamically it was incapable of flight through the Earth's atmosphere. The Lunar Module was the first, and to date only, manned spacecraft to operate exclusively in the airless vacuum of space. Six such craft successfully landed on the Moon between 1969 and 1972. A seventh provided propulsion and life support for the crew of Apollo 13 when their CSM was disabled by an oxygen tank explosion en route to the Moon. The LM's development was plagued with problems which delayed its first unmanned flight by about ten months, and its first manned flight by about three months. Despite this, the LM eventually became the most reliable component of the Apollo/Saturn space vehicle, the only component never to suffer a failure that significantly impacted a mission.〔''Moon Race: The History of Apollo'' DVD, Columbia River Entertainment (Portland, Oregon, 2007)〕 It holds the distinction of being the first, and to date only, manned vehicle to either land on or take off from a natural object in the solar system other than the Earth. ==Operational profile== At launch, the Lunar Module sat directly beneath the Command/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 and 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 LM Pilot entered the LM to temporarily power up and test its systems (except for propulsion). Throughout the flight, he performed the role of an engineering officer, responsible for 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 on systems status and navigational information. After visual inspection of the landing gear by the Command Module Pilot, the LM was withdrawn to a safe distance, then the descent engine was pointed forward into the direction of travel to perform the 30 second Descent Orbit Insertion burn to reduce speed and drop the LM's perilune to within approximately of the surface,〔(Apollo 11 Lunar Orbit Phase )〕 about uprange of the landing site. At this point, the engine was started again for Powered Descent Initiation. 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 the braking phase altitude decreased to approximately , then the final approach phase went to approximately . 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.〔 〕 Finally the landing phase began, approximately uprange of the targeted landing site. At this point manual control was enabled for the Commander, and enough fuel reserve was allocated to allow approximately two minutes of hover time 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, 66 inch (1676 mm) long probes extending from three footpads of the lander touched the surface, activating the contact indicator light which signaled time for descent engine cutoff, allowing the LM to settle on the surface. When ready to leave the Moon, the LM would separate the descent stage and fire the ascent engine to climb back into orbit, using the descent stage as a launch platform. After a few course correction burns, the LM would rendezvous with the CSM and dock for transfer of the crew and rock samples. Having completed its job, the LM was separated and sent into solar orbit or to crash into the Moon. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Apollo Lunar Module」の詳細全文を読む スポンサード リンク
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