NASA LogoNTRSNTRS - NASA Technical Reports ServerSearchmore_vertCollectionsAboutNewsHelpLogin Back to ResultsAffordable Development and Demonstration of a Small Nuclear Thermal Rocket (NTR) Engine and Stage: How Small Is Big Enough?The Nuclear Thermal Rocket (NTR) derives its energy from fission of uranium-235 atoms contained within fuel elements that comprise the engine's reactor core. It generates high thrust and has a specific impulse potential of approximately 900 specific impulse - a 100 percent increase over today's best chemical rockets. The Nuclear Thermal Propulsion (NTP) project, funded by NASA's Advanced Exploration Systems (AES) program, includes five key task activities: (1) Recapture, demonstration, and validation of heritage graphite composite (GC) fuel (selected as the Lead Fuel option); (2) Engine Conceptual Design; (3) Operating Requirements Definition; (4) Identification of Affordable Options for Ground Testing; and (5) Formulation of an Affordable Development Strategy. During fiscal year (FY) 2014, a preliminary Design Development Test and Evaluation (DDT&E) plan and schedule for NTP development was outlined by the NASA Glenn Research Center (GRC), Department of Energy (DOE) and industry that involved significant system-level demonstration projects that included Ground Technology Demonstration (GTD) tests at the Nevada National Security Site (NNSS), followed by a Flight Technology Demonstration (FTD) mission. To reduce cost for the GTD tests and FTD mission, small NTR engines, in either the 7.5 or 16.5 kilopound-force thrust class, were considered. Both engine options used GC fuel and a common fuel element (FE) design. The small approximately 7.5 kilopound-force criticality-limited engine produces approximately157 thermal megawatts and its core is configured with parallel rows of hexagonal-shaped FEs and tie tubes (TTs) with a FE to TT ratio of approximately 1:1. The larger approximately 16.5 kilopound-force Small Nuclear Rocket Engine (SNRE), developed by Los Alamos National Laboratory (LANL) at the end of the Rover program, produces approximately 367 thermal megawatts and has a FE to TT ratio of approximately 2:1. Although both engines use a common 35-inch (approximately 89-centimeters) -long FE, the SNRE's larger diameter core contains approximately 300 more FEs needed to produce an additional 210 thermal megawatts of power. To reduce the cost of the FTD mission, a simple one-burn lunar flyby mission was considered to reduce the liquid hydrogen (LH2) propellant loading, the stage size and complexity. Use of existing and flight proven liquid rocket and stage hardware (e.g., from the RL10B-2 engine and Delta Cryogenic Second Stage) was also maximized to further aid affordability. This paper examines the pros and cons of using these two small engine options, including their potential to support future human exploration missions to the Moon, near Earth asteroids (NEA), and Mars, and recommends a preferred size. It also provides a preliminary assessment of the key activities, development options, and schedule required to affordably build, ground test and fly a small NTR engine and stage within a 10-year timeframe.Document ID20160014802Acquisition SourceGlenn Research CenterDocument TypeTechnical Memorandum (TM)AuthorsBorowski, Stanley K.*(NASA Glenn Research Center Cleveland, OH United States)*Sefcik, Robert J.*(NASA Glenn Research Center Cleveland, OH United States)*Fittje, James E.*(Vantage Partners, LLC Brook Park, OH, United States)*McCurdy, David R.*(Vantage Partners, LLC Brook Park, OH, United States)*Qualls, Arthur L.*(Oak Ridge National Lab. TN, United States)*Schnitzler, Bruce G.*(Oak Ridge National Lab. TN, United States)*Werner, James E.*(Idaho National Lab. Idaho Falls, ID, United States)*Weitzberg, Abraham*(Dept. of Energy Consultant Woodland Hills, CA)*Joyner, Claude R.*(Aerojet Rocketdyne, Inc. West Palm Beach, FL, United States)*Date AcquiredDecember 22, 2016Publication DateDecember 1, 2016Subject CategorySpacecraft Propulsion And PowerReport/Patent NumberE-19303AIAA Paper 2015-4524NASA/TM-2016-219402GRC-E-DAA-TN36221Meeting InformationMeeting: AIAA Space 2015Location: Pasadena, CACountry: United StatesStart Date: August 31, 2015End Date: September 2, 2015Sponsors:American Inst. of Aeronautics and AstronauticsFunding Number(s)WBS: WBS 869021.03.03.01.21CONTRACT_GRANT: NNC12BA01BDistribution LimitsPublicCopyrightPublic Use Permitted.KeywordsSpacecraft designLunar flyby missionNuclear rocket enginesAvailable DownloadsNameType20160014802.pdfSTIcloud_downloadcontent_copyvisibilityRelated RecordsIDRelationTitle20190004970See AlsoAffordable Development and Demonstration of a Small NTR Engine and Stage: A Preliminary NASA, DOE, and Industry Assessment20150021872See AlsoAffordable Development and Demonstration of a Small NTR Engine and Stage: A Preliminary NASA, DOE, and Industry Assessment20150011068See AlsoAffordable Development and Demonstration of a Small NTR engine and Stage: A Preliminary NASA, DOE, and Industry Assessmentvisibility_offNo Preview Available
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