Abstract: The sputter erosion of accelerator grid impinged by CEX ions is one of main failure mechanisms for ion thrusters.To evaluate the effect of this mechanism to the life of ion thruster, based on the sputter erosion mechanism of downstream surface of accelerator grid by CEX ions,a probabilistic life model for ion thruster accelerator grid was developed. In addition, the reliability of expected life is evaluated. Life distribution and expected life reliability of the 20cm Xe ion thruster accelerator grid that operated at ground is evaluated by this model. The results indicate that the accelerator lifetime obeyed Gauss distribution and the reliability of accelerator grid lifetime reached to 3kh was 0.9352 when the thruster operated at 6.7×10-3Pa.

Key words: Ion thruster; Accelerator grid; Lifetime; Gauss distribution; Reliability

摘要： 交换电荷离子对加速栅极的溅射腐蚀是离子推力器的关键失效模式之一,基于交换电荷离子对加速栅溅射腐蚀的物理机理,对离子推力器加速栅工作寿命进行了概率性建模。利用该模型对20cm Xe离子推力器加速栅寿命和其达到预期寿命的可靠度进行了评估。结果显示加速栅的寿命近似服从高斯分布,当推力器工作环境压力近似6.7×10-3Pa时,加速栅工作寿命达到3kh的可靠度为0.9352。

关键词: 离子推力器;加速栅极;寿命; 高斯分布,可靠性