Results of a 35-cm Xenon Ion Thruster Endurance Test *†

* Presented as Paper IEPC-01-083 at the 27 International Electric Propulsion Conference, Pasadena, CA, 15-19 October 2001. † Copyright © 2001 by Shoji Kitamura. Published by the Electric Rocket Propulsion Society with permission. An endurance test of a 35-cm xenon ion thruster aiming at 5,000-hour operation was conducted to evaluate the thruster grid life and to find out weak points in the thruster endurance. In April 2001, the total operation time reached 4,994 hours. The ion production cost was almost constant at about 120 W/A in the first half of the test, but increased to about 130 W/A in the second half. The highest temperature of the discharge chamber magnets was raised along with this increase. Thruster disassembly and inspection after the test revealed several eroded parts in the thruster. Grid mass measurements indicated that the screen grid mass was almost unchanged, but that the accelerator and decelerator grids suffered mass loss. Back-sputtering from the ion beam target lowered the accuracy in the measurement. However, rough estimation from the mass loss rate showed that the accelerator grid would endure longer than 20,000 hours.