Abstract: This article developed an ion thruster optic system
sputter erosion depth numerical 3D model by IFE-PIC (Immersed
Finite Element-Particle-in-Cell) and Mont Carlo method, and
calculated the downstream surface sputter erosion rate of accelerator
grid; compared with LIPS-200 life test data. The results of the
numerical model are in reasonable agreement with the measured data.
Finally, we predicted the lifetime of the 20cm diameter ion thruster via
the erosion data obtained with the model. The ultimate result
demonstrated that under normal operating condition, the erosion rate
of the grooves wears on the downstream surface of the accelerator grid
is 34.6μm⁄1000h, which means the conservative lifetime until
structural failure occurring on the accelerator grid is 11500 hours.