Patent ID: 6964396
Filing Date: 2005-11-15
Classification: B64G,F03H

Abstract:
1. A voltage tracking system for an ion thruster comprising: a discharge chamber containing plasma, said plasma having an associated plasma potential; a screen grid adjacent to said discharge chamber, said screen grid having at least one screen grid aperture and an associated screen grid voltage, said screen grid voltage biased relative to said plasma voltage, whereby a plasma sheath is formed that repels electrons and attracts ions in said plasma, such that said ions pass through said screen grid aperture; an accelerator grid adjacent to said screen grid, said accelerator grid having at least one accelerator grid aperture corresponding to said screen grid aperture, said accelerator grid having a corresponding accelerator grid voltage, whereby said ions are accelerated through said accelerator grid aperture; and an accelerator grid voltage controller coupled to said accelerator grid and supplying said accelerator grid voltage, said accelerator grid voltage controller including control logic operative to adjust said accelerator grid voltage, whereby said magnitude of accelerator grid voltage is minimized while preventing backstreaming into said ion thruster.