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An Accelerated Development, Reduced Cost Approach to Lunar/Mars Exploration Using a Modular NTR-Based Space Transportation SystemThe results of integrated systems and mission studies are presented which quantify the benefits and rationale for developing a common, modular lunar/Mars space transportation system (STS) based on nuclear thermal rocket (NTR) technology. At present NASA's Exploration Program Office (ExPO) is considering chemical propulsion for an 'early return to the Moon' and NTR propulsion for the more demanding Mars missions to follow. The time and cost to develop these multiple systems are expected to be significant. The Nuclear Propulsion Office (NPO) has examined a variety of lunar and Mars missions and heavy lift launch vehicle (HLLV) options in an effort to determine a 'standardized' set of engine and stage components capable of satisfying a wide range of Space Exploration Initiative (SEI) missions. By using these components in a 'building block' fashion, a variety of single and multi-engine lunar and Mars vehicles can be configured. For NASA's 'First Lunar Outpost' (FLO) mission, an expendable NTR stage powered by two 50 klbf engines can deliver approximately 96 metric tons (t) to translunar injection (TLI) conditions for an initial mass in low earth orbit (IMLEO) of approximately 198 t compared to 250 t for a cryogenic chemical TLI stage. The NTR stage liquid hydrogen (LH2) tank has a 10 m diameter, 14.5 m length, and 66 t LH2 capacity. The NTR utilizes a UC-ZrC-graphite 'composite' fuel with a specific impulse (Isp) capability of approximately 900 s and an engine thrust-to-weight ratio of approximately 4.3. By extending the size and LH2 capacity of the lunar NTR stage to approximately 20 m and 96 t, respectively, a single launch Mars cargo vehicle capable of delivering approximately 50 t of surface payload is possible. Three 50 klbf NTR engines and the two standardized LH2 tank sizes developed for lunar and Mars cargo vehicle applications would be used to configure the Mars piloted vehicle for a mission as early as 2010. The paper describes the features of the 'common' NTR-based moon/Mars STS, examines performance sensitivities resulting from different 'mission mode' assumptions, and quantifies potential schedule and cost benefits resulting from this modular moon/Mars NTR vehicle approach.
Document ID
19960007720
Document Type
Conference Paper
Authors
Borowski, S. (NASA Lewis Research Center Cleveland, OH, United States)
Clark, J. (NASA Lewis Research Center Cleveland, OH, United States)
Sefcik, R. (NASA Lewis Research Center Cleveland, OH, United States)
Corban, R. (NASA Lewis Research Center Cleveland, OH, United States)
Alexander, S. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
September 1, 1995
Subject Category
AERONAUTICS (GENERAL)
Report/Patent Number
NASA-TM-107050
E-9895
NAS 1.15:107050
Meeting Information
Congress of the Internation al Astronautical Foundation(Washington, DC)
Funding Number(s)
PROJECT: RTOP 242-10-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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