NASCAP Modeling Computations On Large Optics Spacecraft In Geosynchronous Substorm Environments

N.John Stevens; Carolyn K. Purvis

doi:10.1117/12.958454

5 August 1980 NASCAP Modeling Computations On Large Optics Spacecraft In Geosynchronous Substorm Environments

N.John Stevens, Carolyn K. Purvis

Proceedings Volume 0216, Optics in Adverse Environments II; (1980) https://doi.org/10.1117/12.958454
Event: 1980 Los Angeles Technical Symposium, 1980, Los Angeles, United States

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.

Citation Download Citation

N.John Stevens and Carolyn K. Purvis "NASCAP Modeling Computations On Large Optics Spacecraft In Geosynchronous Substorm Environments", Proc. SPIE 0216, Optics in Adverse Environments II, (5 August 1980); https://doi.org/10.1117/12.958454

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