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A Spaceflight Experiment to Determine the Effect of Chamfered Sample Holders on Atomic Oxygen ErosionThe exteriors of low Earth orbit (LEO) spacecraft are subjected to many environmental threats that can cause the surface materials to degrade. One of these threats is atomic oxygen (AO), which is formed by photo dissociation of molecular oxygen by energetic UV radiation. Atomic oxygen exposure can result in oxidative erosion of polymers leading to structural or thermal failure of spacecraft components. The amount of AO erosion expected during a mission can be calculated by knowing the AO erosion yield (Ey, volume loss per incident atom) of the material and the AO fluence expected for the mission. The Ey can be determined through dehydrated mass loss measurements of test samples if one knows the AO fluence, density, and exposure area. Such measurements have been made as part of flight experiments, including the Materials International Space Station Experiment 2 (MISSE 2) Polymers Experiment. The MISSE 2 Polymers Experiment sample holders had chamfered circular apertures that controlled the exposure area, but also allowed some additional AO to scatter from the chamfered edges onto the samples thus causing some samples to erode thru and peel at their perimeter due to this scattering effect. By modeling the scattered AO flux one can predict the actual total AO fluence, and hence more accurate sample Ey. Sample holders with different chamfered-perimeter to exposed-area ratios have been designed for future spaceflight experiments that allow a more accurate determination of the Ey for large area polymers, representative of their use on spacecraft surfaces.
Document ID
20170011269
Document Type
Presentation
Authors
Girish, Kshama (Hathaway Brown School Shaker Heights, OH, United States)
Banks, Bruce A. (Science Applications International Corp. Brook Park, OH, United States)
De Groh, Kim K. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
November 27, 2017
Publication Date
July 18, 2017
Subject Category
Spacecraft Design, Testing and Performance
Space Sciences (General)
Report/Patent Number
GRC-E-DAA-TN43768
Meeting Information
2017 International Space Station Research and Development (ISS R&D) Conference(Washington, DC)
Funding Number(s)
CONTRACT_GRANT: SAA3-1414
CONTRACT_GRANT: NNC12BA01B
WBS: WBS 934844.01.12.04.02
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Earth Orbital Environments
Oxygen Atoms
Erosion
Flight Experiment

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