Abstract
We have studied electrostatic charging and discharging characteristics of dielectric materials for spacecraft, irradiating electron beam. Surface materials such as Teflon and Kapton negatively charge up and reach high surface potentials. Under the simulated irradiation condition of the geomagnetic substorm, discharges occur on the surface and/or through the bulk of the materials. The surface charging phenomenon is also observed by a potential monitor installed on Engineering Test Satellite V of Japan in space environment. These experimental results suggest us the necessity to suppress surface charging. We have studied two suppression methods. One method is to coat a conductive layer on the insulating film. The other is to cancel out the surface charging by ejecting Xe plasma from the neutralizer of an ion engine. We confirmed that these two methods are effective for eliminating the surface charging on the spacecraft which is considered to be encountered in space.
