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Space Suit Radiator Performance in Lunar and Mars EnvironmentsDuring an ExtraVehicular Activity (EVA), both the heat generated by the astronaut's metabolism and that produced by the Portable Life Support System (PLSS) must be rejected to space. The heat sources include the heat of adsorption of metabolic CO2, the heat of condensation of water, the heat removed from the body by the liquid cooling garment and the load from the electrical components. Although the sublimator hardware to reject this load weighs only 3.48 lbs, an additional eight pounds of water are loaded into the unit of which about six to eight are sublimated and lost; this is the single largest expendable during an eight-hour EVA. Using a radiator to reject heat from the Astronaut during an EVA, we can significantly reduce the amount of expendable water consumed by the sublimator. Last year we reported on the design and initial operational assessment tests of our novel radiator designated the Radiator And Freeze Tolerant heat eXchanger (RAFT-X). Herein, we report on tests conducted in the NASA Johnson Space Center Chamber E Thermal Vacuum Test Facility. Up to 800 Btu/h of heat were rejected in lunar and Mars environments with temperatures as cold as -150 F. Tilting the radiator did not cause an observable loss in performance. The RAFT-X endured freeze / thaw cycles and in fact, the heat exchanger was completely frozen three times without any apparent damage to the unit. We were also able to operate the heat exchanger in a partially frozen configuration to throttle the heat rejection rate from 530 Btu/h at low water flow rate down to 300 Btu/h. Finally, the deliberate loss of a single loop heat pipe only degraded the heat rejection performance by about 2 to 5%.
Document ID
20070001010
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Nabity, James
(TDA Research, Inc. Wheat Ridge, CO, United States)
Mason, Georgia
(TDA Research, Inc. Wheat Ridge, CO, United States)
Copeland, Robert
(TDA Research, Inc. Wheat Ridge, CO, United States)
Libberton, Kerry
(TDA Research, Inc. Wheat Ridge, CO, United States)
Trevino, Luis
(NASA Johnson Space Center Houston, TX, United States)
Stephan, Ryan
(NASA Johnson Space Center Houston, TX, United States)
Paul, Heather
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2007
Subject Category
Man/System Technology And Life Support
Meeting Information
Meeting: 37th International Conference on Environmental Systems
Location: Chicago, IL
Country: United States
Start Date: July 9, 2007
End Date: July 12, 2007
Sponsors: Society of Automotive Engineers, Inc.
Funding Number(s)
WBS: WBS 384.06.04.01.05.10
Distribution Limits
Public
Copyright
Other

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