Mitigating Deep Dielectric Charging Effects in Space

Deep dielectric charging/discharging is a serious space environmental effect. Charging electric fields are the fundamental cause of dielectric discharging. In order to quantitatively mitigate deep dielectric charging effects, the GEANT4 toolkit and radiation-induced conductivity model were used to calculate the maximum possible internal charging potential and electric field with different shielding layer thicknesses, dielectric thicknesses, and ground types. The study selected electron spectra from geostationary earth orbit (GEO) and jupiter orbits as the input environment. With these calculations, a criterion for shielding, dielectric thickness, and ground types is provided such that spacecraft engineers may choose the appropriate method to decrease the deep dielectric charging effects. The charging time constants of flame retardant 4 and polytetrafluoroethylene are ~20 and 500 h, respectively, with a little dependence on input electron spectra, ground type, shield thickness, or dielectric thickness. The dielectric characteristics, ground types, and thicknesses, which can significantly change the value of the electric field, are critical for preventing deep dielectric charging. The maximum saturation charging potential and electric field at jupiter orbit are much larger than those at GEO.