Thrust vectoring of ion engines.

Abstract

The causes of thrust vector misalignments in ion engines were studied both analytically and experimentally. It was found that the major cause of such misalignments is translation, or displacement of one of the electrodes in a direction perpendicular to the exhaust beam axis. Maintaining thrust vector alignment within 1° was found to require electrode translational alignment within ±0.002 in. The translation sensitivity was measured using a mechanical deflection system to generate controlled translational displacements while beam profiles were obtained. A system using thermal expansion forces for accelerator displacement was designed. Thrust vectoring through an angle of 5° was demonstrated. The system was tested using a collector designed to provide real-time data on the three Cartesian coordinate components of the thrust vector. Linearity plots for an electrostatic ally deflected ion engine system and the multiaperture deflection system are presented.