The nature of bulk charging and its mitigation in spacecraft design

Bulk charging, in which energetic electrons embed within bulk dielectrics or isolated conductors such as spot shields, building up to potentials in excess of the breakdown potential of the local region, is known to be a causative factor in anomalous operation of high attitude satellites. The mechanism and methods of ameliorating its effects are discussed. A table of maximum expected electron flux spectra as a function of L is presented. Consideration of these maximum fluxes end the fact that the energy associated with a bulk dielectric breakdown is small indicates that bulk charging can be eliminated as a spacecraft problem through shielding (700 mg/cm²) of all cables and circuit boards otherwise exposed to the environment, through providing conductive paths (<10⁹ ohms) for otherwise isolated metallic elements, and through desensitizing digital logic inputs which are serviced by cables