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Nuclear Thermal Rocket/Vehicle Characteristics And Sensitivity Trades For NASA's Mars Design Reference Architecture (DRA) 5.0 StudyThis paper summarizes Phase I and II analysis results from NASA's recent Mars DRA 5.0 study which re-examined mission, payload and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal rocket (NTR) propulsion was again identified as the preferred in-space transportation system over chemical/aerobrake because of its higher specific impulse (I(sub sp)) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit (IMLEO) which is important for reducing the number of Ares-V heavy lift launches and overall mission cost. DRA 5.0 features a long surface stay (approximately 500 days) split mission using separate cargo and crewed Mars transfer vehicles (MTVs). All vehicles utilize a common core propulsion stage with three 25 klbf composite fuel NERVA-derived NTR engines (T(sub ex) approximately 2650 - 2700 K, p(sub ch) approximately 1000 psia, epsilon approximately 300:1, I(sub sp) approximately 900 - 910 s, engine thrust-toweight ratio approximately 3.43) to perform all primary mission maneuvers. Two cargo flights, utilizing 1-way minimum energy trajectories, pre-deploy a cargo lander to the surface and a habitat lander into a 24-hour elliptical Mars parking orbit where it remains until the arrival of the crewed MTV during the next mission opportunity (approximately 26 months later). The cargo payload elements aerocapture (AC) into Mars orbit and are enclosed within a large triconicshaped aeroshell which functions as payload shroud during launch, then as an aerobrake and thermal protection system during Mars orbit capture and subsequent entry, descent and landing (EDL) on Mars. The all propulsive crewed MTV is a 0-gE vehicle design that utilizes a fast conjunction trajectory that allows approximately 6-7 month 1-way transit times to and from Mars. Four 12.5 kW(sub e) per 125 square meter rectangular photovoltaic arrays provide the crewed MTV with approximately 50 kW(sub e) of electrical power in Mars orbit for crew life support and spacecraft subsystem needs. Vehicle assembly involves autonomous Earth orbit rendezvous and docking between the propulsion stages, in-line propellant tanks and payload elements. Nine Ares-V launches -- five for the two cargo MTVs and four for the crewed MTV -- deliver the key components for the three MTVs. Details on mission, payload, engine and vehicle characteristics and requirements are presented and the results of key trade studies are discussed.
Document ID
20120012928
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Borowski, Stanley K.
(NASA Glenn Research Center Cleveland, OH, United States)
McCurdy, David R.
(ASRC Aerospace Corp. Cleveland, OH, United States)
Packard, Thomas W.
(Analex Corp. Cleveland, OH, United States)
Date Acquired
August 26, 2013
Publication Date
June 14, 2009
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
Paper 203599
E-18236
Meeting Information
Meeting: Nuclear and Emerging Technologies for Space 2009
Location: Atlanta, GA
Country: United States
Start Date: June 14, 2009
End Date: June 19, 2009
Distribution Limits
Public
Copyright
Public Use Permitted.
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