Life Tests and Measurements of Ion Thruster Accelerator Grid Erosion

In this paper, life tests and measurements of ion thruster accelerator grid erosion were investigated. The high altitude experimental vacuum system was presented, and the life tests of a 20cm xenon ion thruster have been carried on. Because the measurement of the grid surface erosion is pretty difficult due to the small dimension of the grid hole diameter, so the Depth-From-Focus (DFF) method is used to measure the grid erosion. After 800 hour longduration test, the erosion depth of the accelerator grid was measured. It can be seen that the result in this paper gives a good agreement with the reported “pits and grooves” erosion pattern in earlier literatures. From the results it is shown that after long-duration tests, the ion thruster optics has been eroded and the maximal erosion depth of the accelerator grid reaches 300μm. At this erosion speed, the accelerator grid will be burned through after 1333 hours of working. The design aspects and test results of the ion thruster can provide valuable data for the design of long-life, high specific impulse xenon ion engine further.