Evaluation of Electron-emitting Film for Spacecraft Charging Mitigation (ELFs Charm)

抄録

To protect a satellite from accidents due to spacecraft charging, Kyushu Institute of Technology (Kyutech) is developing a device called ELFs-Charm, which stands for ELectron-emitting Film for Spacecraft CHARging Mitigation. Electron emission from ELFs-Charm was already confirmed in Polar Earth Orbit in 2012 via flight experiment onboard HORYU-II. As a next step, we are considering the practical operation for spacecraft charging mitigation. The present emission level is not enough to increase the satellite potential. We focus our efforts on improving two properties, charging property and the emission threshold. The charging property is measured by how well the differential voltage between the ELFs-charm insulator surface and the satellite chassis increases. The emission threshold is measured by the differential voltage when the electron emission starts. This paper reports the laboratory experimental results to measure the two properties of various samples. The sample made of fluorin resin coating had a good combination of the charging property and the emission threshold that makes it possible to emit electron under realistic ambient electron current density in orbit.