Guide to Mitigating Spacecraft Charging Effects

Appendix I

Expanded Worst-Case Geosynchronous Earth Environments Descriptions

The worst-case geosynchronous environment descriptions in Table I.1 are actually several measured environments that caused large spacecraft charging events. They come from documented measured data as referenced and are presented in a form that can be used in a double Maxwellian fit in a charging code such as Nascap-2k. Note: In Table I-1, Tav, Trms, and the ATS-6 two-Maxwellian parameters are averaged over all angles. The SCATHA two-Maxwellian parameters are for fluxes parallel and perpendicular to the magnetic field.

Table I.1 Worst-Case Geosynchronous Environments

There are three environments (one from the Applied Technology Satellite 6 [ATS-6] and two from the Spacecraft Charging at High Altitudes Satellite [SCATHA]), each of which caused large potentials on the respective satellites. Thus, persons wishing to evaluate a satellite design more carefully could make three runs using all three environmental descriptions. In this manner, the design of a satellite could be checked more thoroughly for charging effects in various worst-case environments.

Other attempts at worst-case Earth geosynchronous environments are presented in Table 2-1 (Section 2.2.2, using a single Maxwellian representation of the environment) and in Tables 2.1 and 2.2 (Section B.2.1). Section B.2.1 suggests a third approach: Start with ...