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The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U.S. National Aeronautics and Space Administration (NASA). Its official program name was ''Space Transportation System'', taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development.〔(【引用サイトリンク】title=Report of the Space Task Group, 1969 )〕 Operational missions launched numerous satellites (including the Hubble Space Telescope), conducted science experiments in orbit, and participated in construction and servicing of the International Space Station. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. From 1981 to 2011 a total of 135 missions were flown, launched from Kennedy Space Center (KSC) in Florida. During that time the fleet totaled 1,322 days, 19 hours, 21 minutes and 23 seconds of flight time. The longest orbital flight of the shuttle was STS-80 at 17 days 15 hours, while the shortest flight was STS-51-L at 1 minute 13 seconds, cut short when the space shuttle ''Challenger'' broke apart during launch. The shuttles docked with Russian space station ''Mir'' nine times and visited the ISS 37 times. The highest altitude achieved by the shuttle was 350 miles when servicing the Hubble Space Telescope. The program flew a total of 355 people representing 16 countries. The Kennedy Space Center served as the landing site for 78 missions while 54 missions landed at Edwards Air Force Base, California and one at White Sands, New Mexico. The first orbiter, ''Enterprise'', was built purely for atmospheric flight tests and had no orbital capability. Four full operational orbiters were initially built: ''Columbia'', ''Challenger'', ''Discovery'', and ''Atlantis''. ''Challenger'' and ''Columbia'' were destroyed in mission accidents in 1986 and 2003 respectively, killing a total of fourteen astronauts. A fifth operational orbiter, ''Endeavour'', was built in 1991 to replace ''Challenger''. The Space Shuttle was retired from service upon the conclusion of STS-135 by ''Atlantis'' on 21 July 2011.〔Jenkins, p. 524〕 ==Flight numbering== The U.S. space shuttle program was officially referred to as the Space Transportation System (STS). Specific shuttle missions were therefore designated with the prefix "STS".〔 Initially, the launches were given sequential numbers indicating order of launch, such as STS-9. This scheme continued for 25 launches and eight cancellations up to STS-33.〔 Subsequent to the Apollo 13 mishap, due to NASA Administrator James M. Beggs' triskaidekaphobia and consequent unwillingness to number a forthcoming flight as STS-13,〔"(Robert L. Crippen )", NASA Johnson Space Center Oral History Project, 26 May 2006.〕〔"(Terry J. Hart )", NASA Johnson Space Center Oral History Project, 10 April 2003.〕〔"(Paul J. Weitz )", NASA Johnson Space Center Oral History Project, 26 March 2000.〕〔"(James D. A. van Hoften )", NASA Johnson Space Center Oral History Project, 5 December 2007.〕 beginning in 1984, each mission was also assigned a code, such as STS-41-B, with the first digit indicating the federal fiscal year offset into the program (so 41-B was scheduled for FY 1984, 51-L originally for FY 1985 and the third flight in FY 1995 would have been named 151-C), the second digit indicating the launch site (1 was Kennedy Space Center and 2 was Space Launch Complex (SLC) 6 at Vandenberg Air Force Base, although Vandenberg was never used), and the letter indicating scheduling sequence. These codes were assigned when the launches were initially scheduled and were not changed as missions were delayed or rescheduled.〔 Although the codes were adopted from STS-41-B through STS-51-L, the sequential numbers were used internally at NASA on all processing paperwork. Flights were assigned with sequential numbers from STS-9 through STS-33. After the ''Challenger'' disaster, NASA restarted with STS-26R, the "reflight" suffix to disambiguate from prior missions. This continued through STS-33R.〔 After the ''Challenger'' disaster, a sequential numbering system only was used, with the number according to counting from the beginning, although, unlike the initial system, the assignment of numbers was based on the initial schedule and may not reflect launch order. The letter indicated that the intermediate numbering system applied, and e.g. flight STS-51 (a mission carried out by ''Discovery'' in 1993) was many years after STS-51-A (''Discovery's'' second flight in 1984).〔 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「List of Space Shuttle missions」の詳細全文を読む スポンサード リンク
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