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Evaluation of Space Power Materials Flown on the Passive Optical Sample AssemblyEvaluating the performance of materials on the exterior of spacecraft is of continuing interest, particularly in anticipation of those applications that will require a long duration in low Earth orbit. The Passive Optical Sample Assembly (POSA) experiment flown on the exterior of Mir as a risk mitigation experiment for the International Space Station was designed to better understand the interaction of materials with the low Earth orbit environment and to better understand the potential contamination threats that may be present in the vicinity of spacecraft. Deterioration in the optical performance of candidate space power materials due to the low Earth orbit environment, the contamination environment, or both, must be evaluated in order to propose measures to mitigate such deterioration. The thirty two samples of space power materials studied here include solar array blanket materials such as polyimide Kapton H and SiO(x) coated polyimide Kapton H, front surface aluminized sapphire, solar dynamic concentrator materials such as silver on spin coated polyimide and aluminum on spin coated polyimide, CV 1144 silicone, and the thermal control paint Z-93-P. The physical and optical properties that were evaluated prior to and after the POSA flight include mass, total, diffuse, and specular reflectance, solar absorptance, and infrared emittance. Additional post flight evaluation included scanning electron microscopy to observe surface features caused by the low Earth orbit environment and the contamination environment, and variable angle spectroscopic ellipsometry to identify contaminant type and thickness. This paper summarizes the results of pre- and post-flight measurements, identifies the mechanisms responsible for optical properties deterioration, and suggests improvements for the durability of materials in future missions.
Document ID
19990047710
Document Type
Technical Memorandum (TM)
Authors
Jaworske, Donald A. (NASA Glenn Research Center Cleveland, OH United States)
deGroh, Kim K. (NASA Glenn Research Center Cleveland, OH United States)
Skowronski, Timothy J. (Cleveland State Univ. Cleveland, OH United States)
McCollum, Tim (Cleveland State Univ. Cleveland, OH United States)
Pippin, Gary (Boeing Co. Kent, WA United States)
Bungay, Corey (Woollam (John A.) Co. Lincoln, NE United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1999
Subject Category
Chemistry and Materials (General)
Report/Patent Number
NAS 1.15:209061
E-11598
NASA/TM-1999-209061
Funding Number(s)
PROJECT: RTOP 632-1A-1F
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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