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Low Earth orbital atomic oxygen environmental simulation facility for space materials evaluationSimulation of low Earth orbit atomic oxygen for accelerated exposure in ground-based facilities is necessary for the durability evaluation of space power system component materials for Space Station Freedom (SSF) and future missions. A facility developed at the National Aeronautics and Space Administrations's (NASA) Lewis Research Center provides accelerated rates of exposure to a directed or scattered oxygen beam, vacuum ultraviolet (VUV) radiation, and offers in-situ optical characterization. The facility utilizes an electron-cyclotron resonance (ECR) plasma source to generate a low energy oxygen beam. Total hemispherical spectral reflectance of samples can be measured in situ over the wavelength range of 250 to 2500 nm. Deuterium lamps provide VUV radiation intensity levels in the 115 to 200 nm range of three to five equivalent suns. Retarding potential analyses show distributed ion energies below 30 electron volts (eV) for the operating conditions most suited for high flux, low energy testing. Peak ion energies are below the sputter threshold energy (approximately 30 eV) of the protective coatings on polymers that are evaluated in the facility, thus allowing long duration exposure without sputter erosion. Neutral species are expected to be at thermal energies of approximately .04 eV to .1 eV. The maximum effective flux level based on polyimide Kapton mass loss is 4.4 x 10 exp 6 atoms/((sq. cm)*s), thus providing a highly accelerated testing capability.
Document ID
19930018077
Document Type
Conference Paper
Authors
Stidham, Curtis R. (Sverdrup Technology, Inc. Brook Park, OH., United States)
Banks, Bruce A. (NASA Lewis Research Center Cleveland, OH, United States)
Stueber, Thomas J. (Sverdrup Technology, Inc. Brook Park, OH., United States)
Dever, Joyce A. (NASA Lewis Research Center Cleveland, OH, United States)
Rutledge, Sharon K. (NASA Lewis Research Center Cleveland, OH, United States)
Bruckner, Eric J. (Cleveland State Univ. OH., United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1993
Subject Category
CHEMISTRY AND MATERIALS (GENERAL)
Report/Patent Number
NAS 1.15:106128
E-7797
NASA-TM-106128
Meeting Information
International SAMPE Symposium and Exhibition(Anaheim, CA)
Funding Number(s)
PROJECT: RTOP 474-46-10
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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