Grid Gap Variation of Ion Thruster During Startup in Orbit

The grids play a central role in ion thrusters and considerably affect both the performance and lifetime. In this article, the primary goal is to study the variation of the grid gap during the startup process of an ion thruster in orbit. Therefore, we established a detailed model of ion thrusters using ANSYS. We have carried out several experiments to valid both thermal and mechanical performances of the model. The results reveal that the temperature of the ion thruster in orbit periodically varies. The grid gap between the screen grid and the accelerator grid decreases at first and then increases during the startup process, in which the minimum depends on the initial temperature and the thermal control. Higher temperature and more thermal control will raise the minimum gap. To launch a 30-cm-diameter ion thruster from the lowest temperature point and ensure a safe gap, 50 °C thermal control would do a great help.