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Atomic oxygen undercutting of LDEF aluminized-Kapton multilayer insulationAtomic oxygen undercutting is a potential threat to vulnerable spacecraft materials which have atomic oxygen protective coatings. Such undercutting is due to atomic oxygen attack of oxidizable materials at microscopic defects in the protective coatings. These defects occur during fabrication and handling, or from micrometeoroid and debris bombardment in space. An aluminized-polyimide Kapton multilayer insulation sample that was located on the leading edge of the Long Duration Exposure Facility (LDEF) was used to study low Earth orbit directed ram atomic oxygen undercutting. Cracks in the aluminized coatings located around vent holes provided excellent defect sites for evaluation of atomic oxygen undercutting. The experimentally observed undercutting profiles were compared to predictions from Monte Carlo models for normal incident ram atomic oxygen attack. The shape of the undercut profile was found to vary with crack width, which is proportional to the number of oxygen atoms entering the crack. The resulting profiles of atomic oxygen which occurred on LDEF indicated wide undercut cavities in spite of the fixed ram orientation. Potential causes of the observed undercutting are presented. Implications of the undercutting profiles relevant to the Space Station Freedom are also discussed.
Document ID
19920015575
Document Type
Conference Paper
Authors
Degroh, Kim K. (NASA Lewis Research Center Cleveland, OH, United States)
Banks, Bruce A. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1992
Publication Information
Publication: NASA. Langley Research Center, LDEF: 69 Months in Space. First Post-Retrieval Symposium, Part 2
Subject Category
ATOMIC AND MOLECULAR PHYSICS
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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