空间站快速充电事件的机理研究

Mechanism of rapid-charging events for international space station

空间站等大型航天器由于采用高压太阳电池阵而引发的带电问题成为近年来航天器带电研究领域的热点问题.近年来观测到国际空间站(ISS)在出地影瞬间产生的"快速带电"事件(也称"异常带电"),再度引起了对低轨道航天器充电效应的深入研究."快速带电"事件的特征为,集中出现在出地影的瞬间,在几秒内快速上升到较高电位(30—70V),然后在几十秒时间内缓慢衰降,相对高压电池阵本身引起的结构体带电(称为"正常带电",一般在30V以下)严重得多.目前国际上对"快速带电"的研究尚不充分.本文在Furguson等人机理研究工作的基础上,首次建立了描述"快速带电"事件的物理模型,定量揭示了其充电过程的主要机理.根据该模型对国际空间站的"快速带电"进行计算,结果与观测到的典型充电脉冲符合,模型预测的快速带电事件的统计规律也与观测结果基本一致.

The high negative amplitude rapid-charging events （RCEs）, which were observed by the floating potential measurement unit （FPMU） on the International Space Station （ISS） and occurred at the eclipse exit, have attracted a lot of attention recently and are not yet understood. The RCEs are most serious of all types of ISS charging phenomena. Compared with the normal-charging events （NCEs） which occurred on morning sector, the RCEs are characteristic of rapid rise time （＆lt; 10 seconds） and higher amplitude （30—70 V）. In particular, their occurrence at the morning terminator indicates that they are related to the solar panel excitation process at the moment of receiving solar illumination. In this paper, an electric circuit model for the charging of the ISS structure and solar panel is established, based on which a differential equation is developed, with the different charging mechanisms included and also the way of solar panel excitation considered. The calculation results for the RCEs agree well with the typical waveforms.