Thermally Stress-Free Grid Mounting with Hinges for Ion Thrusters

This paper describes a new grid mounting system using hinges for ion thrusters. Hinged grid spacers apply no stress to a grid concerning i ts thermal expansion and yield sufficient stiffness cooperatively with the grid against accel erations in any directions. The grids’ displacements are thermo-elastically analyzed by fi nite element method and the hinged mounting is compared with a conventional flexible o ne. Three-dimensional solid elements, which were found to provide more accurate axial displacements than plate and shell elements, are adopted in the analysis. The axial di splacements of the grids with the hinged mounting are generally larger than those with the f lexible one; however, the differential displacements between screen and accel grids can be smaller with the hinged one. An ion extraction system was assembled with hinges and tested.