Research Of Deep Dielectric Charging And Discharging In Spacecraft

Deep dielectric charging and discharging effect is one of the key factors threatening satellites safety in space environment. The statistic result from recent 25 years of satellites anomaly diagnosis shows that, satellite ESD caused 54.2% of all satellite accidents, in which deep charging and discharging effect attributed 45.7%.This paper studies the deep dielectric charging and discharging phenomenon with ground experiment facility. It simulates space radiation environment with an electron gun and Sr90 radiation source in vacuum. The facility radiates dielectrics at constant temperature, and monitors dielectrics surface potential, discharging current and electric field pulse. The paper also develops a radiation induced conductivity model, explaining the exponential relationship between radiation induced conductivity and dose rate. By introducing a new deep charging model, this paper compares the simulation results with experiment results and summarizes the characteristics of deep dielectric charging and discharging.The result shows that, deep dielectric charging effect becomes more serious with increasing the electron beam intensities, dielectric thickness and dielectric resistance. The deep charging equilibrium voltage grows exponentially with electron beam intensities and dielectric resistance. However, the time to reach charging equilibrium is determined by dielectric resistance. Deep dielectric discharging current can reach the amplitude of tens of ampere, and the electric field pulse amplitude could also be tens of voltage per meter. But the discharging pulse only lasts for tens of nanosecond to several microseconds. The experiment result shows that deep dielectric discharging can disturb testing circuit seriously. The experiment results and new model could be used for deep charging analysis and avoiding in spacecraft.