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Solar Effects on Tensile and Optical Properties of Hubble Space Telescope Silver-Teflon(Registered Trademark) InsulationA section of the retrieved Hubble Space Telescope (HST) solar array drive arm (SADA) multilayer insulation (MLI), which experienced 8.25 years of space exposure, was analyzed for environmental durability of the top layer of silver-Teflon (DuPont) fluorinated ethylene propylene (Ag-FEP). Because the SADA MLI had solar and anti-solar facing surfaces and was exposed to the space environment for a long duration, it provided a unique opportunity to study solar effects on the environmental degradation of Ag-FEP, a commonly used spacecraft thermal control material. Data obtained included tensile properties, solar absorptance, surface morphology and chemistry. The solar facing surface was found to be extremely embrittled and contained numerous through-thickness cracks. Tensile testing indicated that the solar facing surface lost 60% of its mechanical strength and 90% of its elasticity while the anti-solar facing surface had ductility similar to pristine FEP. The solar absorptance of both the solar facing surface (0.155 plus or minus 0.032) and the anti-solar facing surface (0.208 plus or minus 0.012) were found to be greater than pristine Ag-FEP (0.074). Solar facing and anti-solar facing surfaces were microscopically textured, and locations of isolated contamination were present on the anti-solar surface resulting in increased localized texturing. Yet, the overall texture was significantly more pronounced on the solar facing surface indicating a synergistic effect of combined solar exposure and increased heating with atomic oxygen erosion. The results indicate a very strong dependence of degradation, particularly embrittlement, upon solar exposure with orbital thermal cycling having a significant effect.
Document ID
20060056192
Document Type
Technical Memorandum (TM)
Authors
deGroh, Kim, K. (NASA Glenn Research Center Cleveland, OH, United States)
Dever, Joyce A. (NASA Glenn Research Center Cleveland, OH, United States)
Snyder, Aaron (NASA Glenn Research Center Cleveland, OH, United States)
Kaminski, Sharon (Hathaway Brown School Shaker Heights, OH, United States)
McCarthy, Catherine E. (Hathaway Brown School Shaker Heights, OH, United States)
Rapoport, Alison L. (Hathaway Brown School Shaker Heights, OH, United States)
Rucker, Rochelle N. (Hathaway Brown School Shaker Heights, OH, United States)
Date Acquired
August 23, 2013
Publication Date
October 1, 2006
Subject Category
Solar Physics
Report/Patent Number
E-15572
NASA/TM-2006-212336
Meeting Information
Materials Research Society (MRS) Spring Meeting (Symposium II: Materials in Extreme Environments)(San Francisco, CA)
Funding Number(s)
WBS: WBS 251.30.00
Distribution Limits
Public
Copyright
Public Use Permitted.

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