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The RS-18 is a reconfigured version of the Rocketdyne Lunar Module Ascent Engine (LMAE), modified to burn liquid oxygen (LOX) and liquid methane (CH4) for NASA's Exploration Systems Architecture Study (ESAS) engine testing in 2008.〔(【引用サイトリンク】title=New RS-18 builds upon LM Ascent Engine heritage )〕 ==Development== The 2005 NASA Exploration Systems Architecture Study (ESAS) recommended that the crew exploration vehicle (CEV) lunar surface access module (LSAM) ascent stage propulsion and service module propulsion systems employ a pressure-fed LOX/liquid methane (CH4) engine. "Green" propellants, such as LOX and liquid methane, offer savings in both performance and safety over equivalently sized hypergolic propulsion systems in spacecraft applications such as ascent engines or service module engines. The mass savings over monomethyl hydrazine (MMH) and nitrogen tetroxide (N2O4) were around 1,000 - 2,000 lbm (450 – 910 kg) for the LSAM ascent module, which was larger than the current design. The thrust levels identified in ESAS were 5,000 - 10,000 lbf (22 - 44 kN) for the ascent engine. To remove key technology risks in the decision for hypergolic or LOX/Methane, the Propulsion and Cryogenics Advanced Development (PCAD) project is being conducted within NASA, led by the Glenn Research Center, for 5,500 lbf (24,500 N) ascent engine technology. 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「RS-18」の詳細全文を読む スポンサード リンク
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