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Proceedings Paper

NASCAP Modeling Computations On Large Optics Spacecraft In Geosynchronous Substorm Environments
Author(s): N.John Stevens; Carolyn K. Purvis
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Paper Abstract

Satellites in geosynchronous orbits have been found to be charged to significant negative voltages during encounters with geomagnetic substorms. When satellite surfaces are charged, there is a probability of enhanced contamination from charged particles attracted back to the satellite by electrostatic forces. This could be particularily disturbing to large satellites using sensitive optical systems. In this study the NASA Charging Analyzer Program (NASCAP) is used to evaluate qualitatively the possibility of such enhanced contamination on a conceptual version of a large satellite. The evaluation is made by computing surface voltages on the satellite due to encounters with substorm environments and then com-puting charged-particle trajectories in the electric fields around the satellite. Particular attention is paid to the possibility of contaminants reaching a mirror surface inside a dielectric tube because this mirror represents a shielded optical surface in the satellite model used. Deposition of low energy charged particles from other parts of the spacecraft onto the mirror was found to be possible in the assumed moderate substorm environment condition. In the assumed severe substorm environment condition, however, voltage build up on the inside and edges of the dielectric tube in which the mirror is located prevents contaminants from reaching the mirror surface.

Paper Details

Date Published: 5 August 1980
PDF: 15 pages
Proc. SPIE 0216, Optics in Adverse Environments II, (5 August 1980); doi: 10.1117/12.958454
Show Author Affiliations
N.John Stevens, National Aeronautics and Space Administration (United States)
Carolyn K. Purvis, National Aeronautics and Space Administration (United States)

Published in SPIE Proceedings Vol. 0216:
Optics in Adverse Environments II
Mark A. Kahan, Editor(s)

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