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DIRECT was a late-2000s proposed alternative heavy lift launch vehicle architecture supporting NASA's Vision for Space Exploration, which would replace the space agency's planned Ares I and Ares V rockets with a family of Shuttle-Derived Launch Vehicles named "Jupiter". DIRECT was advocated by a group of space enthusiasts who asserted that they represented a broader team of dozens of NASA and space industry engineers who actively worked on the proposal on an anonymous, voluntary basis in their spare time. , the DIRECT Team was said to consist of 69 members,〔 〕 62 of whom were NASA engineers, NASA-contractor engineers, and managers from the Constellation Program. A small number of non-NASA members of the team publicly represented the group. The project name "DIRECT" referred to a philosophy of maximizing the re-use of hardware and facilities already in place for the Space Shuttle program (STS), hence a "direct" transition. The DIRECT Team asserted that using this approach to develop and operate a family of high-commonality rockets would reduce costs and the gap between retirement of the Space Shuttle and the first launch of Orion, shorten schedules, and simplify technical requirements for future US human space efforts. Three major versions of the DIRECT proposal were released with the last, Version 3.0, unveiled in May 2009. On 17 June 2009, the group presented its proposal at a public hearing of the Review of U.S. Human Space Flight Plans Committee, a panel reviewing US space efforts, in Washington D.C. With the October 11th signing of the NASA Authorization Act of 2010 (S. 3729) by President Obama mandating work on the Space Launch System Heavy Lift Launch Vehicle, the DIRECT Team declared their effort a success and disbanded. Some members subsequently announced the formation of a new space technology company: C-Star Aerospace, LLC.〔(NASA Has New Authorization but Future Remains Uncertain | SpaceNews.com )〕〔http://www.launchcomplexmodels.org/Direct/documents/Direct-Team-Declares-Success-PR-101310.pdf〕 == Jupiter launch vehicle family == (詳細はSpace Shuttle External Tank with a pair of standard four-segment Solid Rocket Boosters (SRBs) mounted at the sides as on the Space Shuttle. Up to four Space Shuttle Main Engines (SSMEs) from the Space Shuttle Orbiter would be attached to the bottom of the External Tank. The engines would be deorbited along with the expended tank to burn up in the Earth's atmosphere. For flights lifting payloads massing 70 Tonnes or less, the Jupiter would fly with no upper stage and utilize only three SSMEs. This configuration was designated the Jupiter-130, indicating one cryogenic stage to reach orbital insertion, three SSMEs powering this common core stage and no engines on the upper stage (because there is no upper stage). For heavier payloads a proposed Jupiter Upper Stage (JUS) would be added atop the tank structure and a fourth SSME would be mounted on the base of the common core stage. This configuration was designated the Jupiter-246, indicating two cryogenic stages to reach orbital insertion, four SSMEs powering the Common core stage and six RL-10 cryogenic engines powering the JUS. For extra-planetary expeditions, the JUS would serve in a role similar to the Earth Departure Stage planned for Ares V. DIRECT specified existing components for their launch vehicles, but contended that they could incorporate improvements such as the more powerful five-segment SRB and J-2X upper stage engine currently under development for the Constellation Program should they become available. Crews would be carried atop the launch vehicle in NASA's planned Orion Crew Exploration Vehicle, itself topped by the planned Launch Abort System. Cargo, whether carried behind the Orion spacecraft or alone on a cargo-only launch would be enclosed by a payload fairing. Many configurations of Jupiter were seen as possible, but the DIRECT version 3.0 proposal, released in May 2009, recommended two: the Jupiter-130 and Jupiter-246, with claimed lift capacities exceeding 70 and 110 tonnes, respectively, to low Earth orbit.〔 〕 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「DIRECT」の詳細全文を読む スポンサード リンク
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