Share Email Print
cover

Proceedings Paper

Observations on one-dimensional counterflow diffusion problem
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

The proposed paper will describe development of a time-dependent, one-dimensional counterflow diffusion model meant to help study the issue of helium exposure of the IRU (Inertial Reference Unit) used in the Earth Observing-1 (EO-1) spacecraft. The IRU features sensitive quartz crystal hemispherical resonating gyros (HRG's). Although the IRU enclosure was purged with high-purity liquid boil-off nitrogen, the HRG's were still quite susceptible to contamination generated by exposure of the enclosure to levels of helium above atmospheric background levels. This helium would be preferentially collected by the HRG's, changing their mass, and hence the driving voltage required for operations. The paper will discuss a comparison of theoretical results with test data for an IRU enclosure, and how contaminant gases can enter vent holes despite the presence of a purge. These observations are then used to describe a possible improvement for purge effectiveness.

Paper Details

Date Published: 11 September 2002
PDF: 6 pages
Proc. SPIE 4774, Optical System Contamination: Effects, Measurements, and Control VII, (11 September 2002); doi: 10.1117/12.481646
Show Author Affiliations
Michael S. Woronowicz, Swales Aerospace (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)

© SPIE. Terms of Use
Back to Top