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Proceedings Paper

Application of ASTM E-1559 apparatus to study H2O desorption
Author(s): M. Woronowicz; G. Meadows
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Paper Abstract

In the harsh vacuum environment of deep space, surfaces shielded from the Sun may easily develop temperatures low enough to condense water vapor for extended periods of time. The condensed vapor will subsequently desorb at rates consistent with its temperature-sensitive equilibrium vapor pressure, and under certain circumstances it is important to predict this release rate. A review of available scientific literature to confirm model predictions indicated no such measurements had been reported below 131 K. Contamination control personnel at NASA Goddard Space Flight Center recognized the possibility they readily possessed the means to collect such measurements at lower temperatures with an existing apparatus commonly used for making outgassing observations. This paper will describe how the ASTM E-1559 “MOLEKIT” apparatus was used without modification to measure water vapor sublimation down to 120 K and compare this data to existing equilibrium vapor pressure models. In addition, an in-depth analysis of theoretical formulations for vapor pressure gives insight into the physical basis underlying characteristics associated with high-fidelity models.

Paper Details

Date Published: 15 October 2012
PDF: 10 pages
Proc. SPIE 8492, Optical System Contamination: Effects, Measurements, and Control 2012, 849209 (15 October 2012); doi: 10.1117/12.946556
Show Author Affiliations
M. Woronowicz, SGT, Inc. (United States)
G. Meadows, SGT, Inc. (United States)

Published in SPIE Proceedings Vol. 8492:
Optical System Contamination: Effects, Measurements, and Control 2012
Sharon A. Straka; Nancy Carosso; Joanne Egges, Editor(s)

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