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Proceedings Paper

Contamination environment resulting from IUS stage II motor post-burn outgassing
Author(s): David J. Kirshman
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Paper Abstract

A parametric study is presented in which the contamination environment established to aft facing spacecraft surfaces subsequent to burnout of the Inertial Upper Stage (IUS) second stage motor is characterized. Subsequent to motor burnout, the internal motor case, insulation, and materials in the flexible nozzle seal assembly of the IUS will continue to outgas and expel large hydrocarbon molecules. By means of molecular scattering, these outgassing products may be transported to payload (spacecraft) surfaces creating a potentially severe contamination environment on sensitive components. Transport of the outgassing products is characterized using the Direct Simulation Monte Carlo (DSMC) method. Since many of the physical attributes of the outgassed products are unknown, a parametric study is performed in which the outgassing temperature, reference viscosity, and molecular weight of the products are varied. In addition, inclusion or exclusion of an extendible nozzle exit cone provides the effect of nozzle length on the contamination environment. Contour plots of the resulting flowfield number density are provided in addition to incident mass flux to aft facing surfaces of a representative spacecraft.

Paper Details

Date Published: 11 September 2002
PDF: 12 pages
Proc. SPIE 4774, Optical System Contamination: Effects, Measurements, and Control VII, (11 September 2002); doi: 10.1117/12.481649
Show Author Affiliations
David J. Kirshman, Boeing Space and Communications Group (United States)

Published in SPIE Proceedings Vol. 4774:
Optical System Contamination: Effects, Measurements, and Control VII
Philip T. C. Chen; O. Manuel Uy, Editor(s)

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