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The Command/Service Module (CSM) was one of two spacecraft, along with the Lunar Module, used for the United States Apollo program which landed astronauts on the Moon. It was built for NASA by North American Aviation. It was launched by itself on three suborbital and low Earth orbit Apollo test missions using the Saturn IB launch vehicle. It was also launched twelve times on the larger Saturn V launch vehicle, both by itself and with the Lunar Module. It made a total of nine manned flights to the Moon aboard the Saturn V. After the Apollo lunar program, the CSM saw manned service as a crew shuttle for the Skylab program, and the Apollo-Soyuz Test Project in which an American crew rendezvoused and docked with a Soviet Soyuz spacecraft in Earth orbit. The CSM consisted of two segments: the Command Module, a cabin that housed a crew of three and equipment needed for re-entry and splashdown; and a Service Module that provided propulsion, electrical power and storage for various consumables required during a mission. The Service Module was cast off and allowed to burn up in the atmosphere before the Command Module re-entered and brought the crew home. The CSM was initially designed to return all three astronauts from the lunar surface on a direct-descent mission which would not use a separate Lunar Module, and thus had no provisions for docking with another spacecraft. This, plus other required design changes led to the decision to design two versions of the CSM: Block I was to be used for unmanned missions and a single manned Earth orbit flight (''Apollo 1''), while the more advanced Block II was designed for use with the Lunar Module. The Apollo 1 flight was cancelled after a cabin fire killed the entire crew and destroyed the Command Module during a launch rehearsal test. Corrections of the problems which caused the fire were applied to the Block II spacecraft, which was used for all manned missions. ==Development history== When NASA awarded the initial Apollo contract to North American Aviation on November 28, 1961, it was still assumed the lunar landing would be achieved by direct descent rather than by lunar orbit rendezvous. Therefore, design proceeded without a means of docking the Command Module to a Lunar Excursion Module (LEM). But the change to lunar orbit rendezvous, plus several technical obstacles encountered in some subsystems (such as environmental control), soon made it clear that substantial redesign would be required. In 1963, NASA decided the most efficient way to keep the program on track was to proceed with the development in two versions: * Block I would continue the preliminary design, to be used for early low Earth orbit test flights only. * Block II would be the lunar-capable version, including a docking hatch and incorporating weight reduction and lessons learned in Block I. Detailed design of the docking capability depended on design of the LEM, which was contracted to Grumman Aircraft Engineering. By January 1964, North American started presenting Block II design details to NASA.〔 〕 Block I spacecraft were used for all unmanned Saturn 1B and Saturn V test flights. Initially two manned flights were planned, but this was reduced to one in late 1966. This mission, designated AS-204 but named Apollo 1 by its flight crew, was planned for launch on February 21, 1967. But during a dress rehearsal for the launch on January 27, all three astronauts (Virgil I. "Gus" Grissom, Edward H. White, II and Roger Chaffee), were killed in a cabin fire which revealed serious design, construction and maintenance shortcomings in Block I, many of which would have been carried over into Block II. After a thorough investigation by the Apollo 204 Review Board, it was decided to terminate the manned Block I phase and redefine Block II to incorporate the review board's recommendations. Block II incorporated a revised CM heat shield design, which was tested on the unmanned Apollo 4 and Apollo 6 flights, so the first all-up Block II spacecraft flew on the first manned mission, Apollo 7. The two blocks were essentially similar in overall dimensions, but several design improvements resulted in weight reduction in Block II. The Apollo 1 spacecraft weighed 45,000 lb (20,412 kg), while Apollo 7 weighed only 36,993 lb. (16,520 kg.) Also, the Block I Service Module propellant tanks were slightly larger than in Block II. In the specifications given below, unless otherwise noted, all weights given are for the Block II spacecraft. ==Command Module (CM)== The Command Module was a truncated cone (frustum) tall with a diameter of across the base. The forward compartment contained two reaction control engines, the docking tunnel, and the components of the Earth Landing System. The inner pressure vessel housed the crew accommodations, equipment bays, controls and displays, and many spacecraft systems. The last section, the aft compartment, contained 10 reaction control engines and their related propellant tanks, fresh water tanks, and the CSM umbilical cables. 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 Command/Service Module」の詳細全文を読む スポンサード リンク
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