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TITLE AND SUBTITLE:
The Effect of Simulated Lunar Dust on the Absorptivity, Emissivity, and Operating Temperature on AZ-93 and Ag/FEP Thermal Control Surfaces
AUTHOR(S):
Gaier, James, R.; Siamidis, John; Panko, Scott, R.; Rogers, Kerry, J.; Larkin, Elizabeth, M., G.
REPORT DATE:
2008-12-01
FUNDING NUMBERS:
WBS 936374.04.08.03
PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration John H. Glenn Research Center at Lewis Field Cleveland, Ohio 44135-3191
PERFORMING ORGANIZATION REPORT NUMBER:
E-16723
SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration Washington, DC 20546-0001
REPORT TYPE AND DATES COVERED:
Technical Memorandum
SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA/TM-2008-215492
SUPPLEMENTARY NOTES:
ABSTRACT:
JSC-1AF lunar simulant has been applied to AZ-93 and AgFEP thermal control surfaces on aluminum or composite substrates in a simulated lunar environment. The temperature of these surfaces was monitored as they were heated with a solar simulator and cooled in a 30 K coldbox. Thermal modeling was used to determine the absorptivity (α) and emissivity (ε) of the thermal control surfaces in both their clean and dusted states. Then, a known amount of power was applied to the samples while in the coldbox and the steady state temperatures measured. It was found that even a submonolayer of simulated lunar dust can significantly degrade the performance of both white paint and second-surface mirror type thermal control surfaces under these conditions. Contrary to earlier studies, dust was found to affect ε as well as α. Dust lowered the emissivity by as much as 16 percent in the case of AZ-93, and raised it by as much as 11 percent in the case of AgFEP. The degradation of thermal control surface by dust as measured by α/ε rose linearly regardless of the thermal control coating or substrate, and extrapolated to degradation by a factor 3 at full coverage by dust. Submonolayer coatings of dust were found to not significantly change the steady state temperature at which a shadowed thermal control surface will radiate.
SUBJECT TERMS:
Lunar soil; Lunar dust
NUMBER OF PAGES:
21
PDF AVAILABLE FROM URL:
2008/TM-2008-215492.pdf ( 4083 KB )
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