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Potential of a New Lunar Surface Radiator Concept for Hot Lunar Thermal EnvironmentsThe optimum radiator configuration in hot lunar thermal environments is one in which the radiator is parallel to the ground and has no view to the hot lunar surface. However, typical spacecraft configurations have limited real estate available for top-mounted radiators, resulting in a desire to use the spacecraft s vertically oriented sides. Vertically oriented, flat panel radiators will have a large view factor to the lunar surface, and thus will be subjected to significant incident lunar infrared heat. Consequently, radiator fluid temperatures will need to exceed approx.325 K (assuming standard spacecraft radiator optical properties) in order to provide positive heat rejection at lunar noon. Such temperatures are too high for crewed spacecraft applications in which a heat pump is to be avoided. A recent study of vertically oriented radiator configurations subjected to lunar noon thermal environments led to the discovery of a novel radiator concept that yielded positive heat rejection at lower fluid temperatures. This radiator configuration, called the Upright Lunar Terrain Radiator Assembly (ULTRA), has exhibited superior performance to all previously analyzed concepts in terms of heat rejection in the lunar noon thermal environment. A key benefit of the ULTRA is the absence of louvers or other moving parts and its simple geometry. Analysis of the ULTRA for a lunar extravehicular activity (EVA) portable life support system (PLSS) is shown to provide moderate heat rejection, on average, at all solar incident angles assuming an average radiator temperature of 294 K, whereas prior concepts exhibited insignificant heat rejection or heat absorption at higher incident angles. The performance of the ULTRA for a lunar lander is also discussed and compared to the performance of a vertically oriented, flat panel radiator at various lunar latitudes.
Document ID
20080013384
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Ochoa, Dustin A.
(Jacobs Engineering Group, Inc. Houston, TX, United States)
Vogel, Matthew R.
(Jacobs Engineering Group, Inc. Houston, TX, United States)
Trevino, Luis A.
(NASA Johnson Space Center Houston, TX, United States)
Stephan, Ryan A.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2008
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
08ICES-0315
Meeting Information
Meeting: 38th International Conference on Environmental Systems
Location: San Francisco, CA
Country: United States
Start Date: June 29, 2008
End Date: July 3, 2008
Sponsors: Society of Automotive Engineers, Inc.
Funding Number(s)
WBS: WBS 831288.03.04
Distribution Limits
Public
Copyright
Other

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