US Patent 7581380 Air-breathing electrostatic ion thruster

An improved air-breathing electrostatic ion thruster specially configured for use in low-Earth atmosphere comprises a housing having an electrically conductive inner surface defining an ionization chamber. Ambient atmospheric gas passes through a forward screen electrode at the chamber inlet to be ionized by an inner electrode disposed in the chamber. The ions are directed rearward through the aligned apertures of a rearward screen electrode and an accelerator electrode at the chamber outlet to generate thrust. A source of electrical power, which can be solar cells, a battery and/or a generator, provides current of a first polarity to the inner surface, forward screen electrode and rearward screen electrode and current of a second polarity to the inner electrode and accelerator electrode. A controller controls the amount and/or polarity of the current. Magnets disposed about the chamber improve ionization. A neutralizing mechanism near the chamber outlet keeps the ion thruster electrically neutral.