In order to estimate the overall life of the existing three gate module of 30 cm diameter ion thruster, the grid gap under thermal equilibrium state and the erosion velocity of different regions of the grids were simulated and calculated by FEM (finite element method) and PIC-MCC (particle-in-cell-Monte Carlo collision) method respectively. The results show that when the thruster reaches the thermal equilibrium, the overall deformation of the decelerator grid presents central area depression characteristics, and the overall deformation of the accelerator grid presents a uniform protruding. In the center area of the grids with the diameter of 0~70 mm, the mean gap between the two grids decreases by 0.057 mm. Meanwhile, in the annular region with the diameter of 70~140 mm, the mean gap between the two grids increases by 0.129 mm. The erosion velocity of the apertures at the edge of the decelerator grid reaches 6.25×10^-14 kg/s within 1500 h, and which of the aperture at 5700 h decreases 15.4% compared with 1500 h. The erosion velocity of the apertures at the center and edge of the accelerator grid, and the apertures at the center of the decelerator grid decreases 8.0%, 4.1% and 3.6%, respectively. The results of 5700 h life test show that the erosion of the apertures at the center of the decelerator grid, and the apertures at the center and edge of the accelerator grid are basically linear, and the comparison error between the simulation and test is within 10%.

A thermal simulation model of 5 A emission current hollow cathode was established by using finite element method, and the model verification and temperature analysis under typical working condition were investigated. The results show that the model can better reflect the energy transmission process inside the hollow cathode. The comparison error between the simulation results and the test results is less than 5%. The temperature difference of hollow cathode is mainly caused by heating current. The ambient temperature mainly affect the external components of hollow cathode, and the high ambient temperature under the influence of solar irradiation is more conducive to the start-up of the thruster. When the hollow cathode is heated and in self-sustaining discharge state, the temperature of the emitter reaches 2122 ℃ and 2126 ℃ at the ambient temperatures of 0 ℃ and 94 ℃, respectively, which is close to the temperature resistance limit of the emitter. Therefore, the hollow cathode must avoid the extreme condition.