| 摘要 |
An electric propulsion system including a plasma chamber having a first output aperture having first acceleration and screen grids, and a second output aperture having second acceleration and screen grids. The screen grids are maintained at a constant positive potential. In use, ions are expelled from the two apertures in anti-parallel directions. By independently controlling the potentials of the acceleration grids to adjust the rates of ion extraction from the output apertures, small resultant thrusts at the muN level may be obtained and the resultant thrust maybe continuously reduced to zero. By closing off apertures of one of the screen grids, thrust at the mN may be obtained with sub-muN accuracy. The system therefore provides functionality previously achievable only with plural types of electric propulsion system, providing weight and complexity savings for satellites or space-probes comprising such systems.
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