行星际粒子统计特征及其在深空探测用器件失效概率预估中的应用

Statistical characteristics of interplanetary particles and their application in estimating failure probability of devices for deep space missions

文章针对深空探测任务高能粒子辐射及所致器件失效定量评估问题,利用IMP-8在1973年-2001年的电子探测数据,统计了太阳电子事件通量的特征,证明事件通量符合对数正态分布。假设事件发生概率符合泊松分布,构建了行星际电子通量模型,再结合太阳质子通量模型、探测器轨道、行星际粒子在日球层的传播规律,得到不同置信度下空间粒子通量及其剂量。进一步结合器件累计失效剂量的试验数据,可定量评估器件失效概率。以一种典型的商用数据采集功能模块器件TL084和火星环绕探测任务为例,7个月转移轨道和3年火星轨道的任务期内,1 mm铝屏蔽下TL084的失效概率仅为1.01%。

The energetic protons and electrons pervading the interplanetary space constitute the main source of radiation in the deep space missions, especially in the transfer orbits. Using the historical data of the IMP-8’s electron detection during 1973 through 2001, the statistical characteristics of the flux of the solar electron events are analyzed. It is shown that they follow a lognormal distribution. Assuming that the electron event occurs in a Poisson distribution, we establish an interplanetary electron flux model. By integrating the solar proton flux model, the orbit of the deep space mission, and the propagation law of the electron event in the heliosphere, the particle fluxes and the doses at different confidence levels are obtained. Then the failure probability of a certain device can be evaluated quantitatively based on its cumulative failure dose record. Taking the TL084 data acquisition module in the Mars mission with 8 month transfer orbit and 3 year Mars orbit as an example, the calculated failure probability is 1.01%.