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Low earth orbit durability of protected silicone for refractive photovoltaic concentrator arraysPhotovoltaic power systems with novel refractive silicone solar concentrators are being developed for use in low Earth orbit (LEO). Because of the vulnerability of silicones to atomic oxygen and ultraviolet radiation, these lenses are coated with a multilayer metal oxide protective coating. The objective of this work was to evaluate the effects of atomic oxygen and thermal exposures on multilayer coated silicone. Samples were exposed to high-fluence ground-laboratory and low-fluence in-space atomic oxygen. Ground testing resulted in decreases in both total and specular transmittance, while in-space exposure resulted in only small decreases in specular transmittance. A contamination film, attributed to exposed silicone at coating crack sites, was found to cause transmittance decreases during ground testing. Propagation of coating cracks was found to be the result of sample heating during exposure. The potential for silicone exposure, with the resulting degradation of optical properties from silicone contamination, indicates that this multilayer coated silicone is not durable for LEO space applications where thermal exposures will cause coating crack development and propagation.
Document ID
19960027889
Document Type
Reprint (Version printed in journal)
Authors
McCollum, Timothy A. (Cleveland State Univ. OH United States)
deGroh, Kim K. (NASA Cleveland, OH United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1995
Subject Category
Energy Production and Conversion
Report/Patent Number
NASA-TM-110121
NAS 1.15:110121
Meeting Information
Aerospace Sciences Meeting(Reno, NV)
Distribution Limits
Public
Copyright
Public Use Permitted.

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NameType 19960027889.pdf STI