Appendix C: Environment, Electron Transport, and Spacecraft Charging Computer Codes

Abstract

Codes are listed below in alphabetical order. Note that some codes do both environments and transport but are listed in one place only. C.1.1 AE8/AP8The NASA AE8 (electrons) and AP8 (protons) radiation models are the traditional electron and proton models of Earth's radiation environment. The AE8 predictions for GEO are probably the most used estimates of the average environment. In these codes, the fluxes are long-term averages (~5 years or more). There are two versions of each model-AE8 solar minimum and AE8 solar maximum and AP8 solar minimum and AP8 solar maximum. They do not predict the peak electron fluxes that are necessary for the internal charging calculations recommended in this book. Reference [1] reviews the output and problems with the AE8/AP8 models. (Note: as of publication of this book, the new AE9/AP9 radiation models had just gone out for beta testing-they were expected to be formally released in late 2011.) C.1.2 CRRESCRRES monitored Earth's radiation belts in an eccentric orbit for 14 months starting in July 1990. The data from the spacecraft are in the form of electron and proton flux and dose-depth curves as functions of time and altitude. Environment codes from CRRES include CRRESRAD (dose versus depth); CRRESPRO (proton flux energy spectrum); and CRRESELE (electron flux energy spectrum). They are available from the Air Force Research Laboratory