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Proceedings Paper

Thermal vacuum chamber repressurization with instrument purging
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Paper Abstract

At the conclusion of cryogenic vacuum testing of the James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (JWST-OTIS) in NASA Johnson Space Center’s (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are postulating that chamber particulate material stirred up by the repressurization process may be kept from falling into the Integrated Science Instrument Module (ISIM) interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This manuscript describes development of a series of models designed to describe this process. The models are strung together in tandem with a fictitious set of conditions to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

Paper Details

Date Published: 27 September 2016
PDF: 10 pages
Proc. SPIE 9952, Systems Contamination: Prediction, Control, and Performance 2016, 99520B (27 September 2016); doi: 10.1117/12.2238756
Show Author Affiliations
Michael S. Woronowicz, Stinger Ghaffarian Technologies, Inc. (United States)

Published in SPIE Proceedings Vol. 9952:
Systems Contamination: Prediction, Control, and Performance 2016
Joanne Egges; Carlos E. Soares; Eve M. Wooldridge, Editor(s)

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