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}} The DC-X, short for Delta Clipper or Delta Clipper Experimental, was an unmanned prototype of a reusable single-stage-to-orbit launch vehicle built by McDonnell Douglas in conjunction with the United States Department of Defense's Strategic Defense Initiative Organization (SDIO) from 1991 to 1993. Starting 1994 until 1995, testing continued through funding of the US civil space agency NASA.〔(【引用サイトリンク】url=http://www.hq.nasa.gov/pao/History/x-33/dcxtests.html#flight4 )〕 In 1996, the DC-X technology was completely transferred to NASA, which upgraded the design for improved performance to create the DC-XA. ==Background== According to writer Jerry Pournelle: "DC-X was conceived in my living room and sold to National Space Council Chairman Dan Quayle by General Graham, Max Hunter and me." According to Max Hunter, however, he had tried hard to convince Lockheed-Martin of the concept's value for several years before he retired.〔Statement by Max Hunter, White Sands, May 16, 1995 in conversation with Dave Klingler〕 Hunter had written a paper in 1985 entitled "The Opportunity", detailing the concept of a Single-Stage-To-Orbit spacecraft built with low-cost "off-the-shelf" commercial parts and currently-available technology,〔The Rise and Fall of the SDIO's SSTO Program, From the X-Rocket to the Delta Clipper", Andrew J. Butrica, NASA〕 but Lockheed-Martin was not interested enough to fund such a program themselves. On February 15, 1989, Pournelle, Graham and Hunter were able to procure a meeting with Vice-President Dan Quayle. They "sold" the idea to SDIO by noting that any space-based weapons system would need to be serviced by a spacecraft that was far more reliable than the Space Shuttle, and offer lower launch costs and have much better turnaround times. Given the uncertainties of the design, the basic plan was to produce a deliberately simple test vehicle and to "fly a little, break a little" in order to gain experience with fully reusable quick-turnaround spacecraft. As experience was gained with the vehicle, a larger prototype would be built for sub-orbital and orbital tests. Finally a commercially acceptable vehicle would be developed from these prototypes. In keeping with general aircraft terminology, they proposed the small prototype should be called the DC-X, X for "experimental". This would be followed by the "DC-Y", Y referring to pre-run prototypes of otherwise service-ready aircraft. Finally the production version would be known as the "DC-1". The name "Delta Clipper" was chosen deliberately to result in the "DC" acronym, an homage to the famous Douglas DC-3 aircraft, which many credit for making passenger air travel affordable. 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「McDonnell Douglas DC-X」の詳細全文を読む スポンサード リンク
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