An ignitor subsystem for use in an electric propulsion system is disclosed. The igniter subsystem includes an igniter, which includes a first electrically conducting electrode, a second electrically conducting electrode, and an electrically insulating layer sandwiched between the first and the second electrically conducting electrodes, and a voltage pulse generator electrically coupled to the first and the second electrically conducting electrodes and is adapted to generate a plurality of pulses each with sufficient voltage to cause a breakdown of the electrically insulating layer, thus causing an avalanche of electrons from one of the first and the second electrically conducting electrodes to the other, the voltage pulse generator is further adapted to limit energy transferred to the igniter in each of the plurality of pulses so as to minimize damage to the igniter.

A discharge chamber of an ion drive, an ion drive having a discharge chamber, and a diaphragm for being affixed in a discharge chamber of an ion drive. The discharge chamber comprises a diaphragm, wherein the diaphragm of the discharge chamber comprises a magnet and is disposed and/or affixed in the discharge chamber.

A Hall effect thruster arranged inside a wall and including a magnetic circuit and an electric circuit including an anode, a first cathode, and a voltage source. The magnetic circuit and the electric circuit are arranged in such a manner as to generate magnetic and electric fields around the wall. In every meridian section, the magnetic circuit presents an upstream magnetic pole and a downstream magnetic pole arranged at the surface of the wall and spaced apart from each other; and the anode and the first cathode are situated on either side of the upstream magnetic pole.

Electrically conductive aerogel and methods of making the same are disclosed. A solution is provided. The solution is cured to form a polymer. The polymer is carbonized to form the conductive aerogel.

A control device includes an acquiring unit and a processing unit. The acquiring unit acquires a voltage course and a current course of a determinable number of periods of a frequency generator and transmits these to the processing unit. The processing unit determines a temporal offset ?t.sub.1 between a rising edge of the current course and a rising edge of the voltage course for each period of the determinable number of periods, and further determines if this temporal offset ?t.sub.1 is positive or negative. The processing unit determines a difference between the number of periods with positive temporal offset and the number of periods with negative temporal offset within the determinable number of periods, and generates and adapts a switching signal for a switch-on time of the voltage course if the number of periods with positive temporal offset differs from the number of periods with negative temporal offset.

Hall thrusters with conductive coatings are disclosed. A Hall thruster comprises magnetic shielding in order to avoid collisions with the inner walls of its discharge chamber. By removing the source of erosion, the walls of the chamber can be removed reducing mass, cost and complexity of the thruster. A conductive coating, such as an aluminum coating, is deposited on inner screens between the discharge chamber and the magnetic poles of the thruster. The magnetic field within the chamber shields the conductive coating deposited on the inner and outer screens of the chamber.

Disclosed herein is a propulsion system comprising: a solid conductive or semiconductive cathode (130); an anode (110) having a potential difference relative to said cathode (130), said potential difference creating an electric field between said anode (110) and said cathode (130); and an insulated trigger (150) adapted to trigger an arc discharge from a point on a upper surface of said cathode (130) in pulses, when said trigger (150) and cathode (130) are substantially in a vacuum, said trigger being bounded within the cathode so that the point at which the arc is triggered is located on the upper surface of said cathode.

Embodiments relate to a hallow cathode with integral layers of radiation shielding. The hollow cathode includes an inner cathode tube that forms a gas feed to direct gas toward a downstream end, where the directed gas forms plasma. A heater element is positioned at the downstream end of the inner cathode tube, the heater element to heat the plasma. The hollow cathode further includes an outer cathode tube with a keeper electrode to sustain a bias voltage across a gap at a downstream end of the outer cathode tube for igniting the plasma. The integral layers of radiation shielding are connected by offset radial supports and are incorporated as a single element with either the inner or outer cathode tube, where the integral layers are nested with torturous conductive paths to reduce radiation and conduction losses from the downstream end of the inner cathode tube.

An exemplary air-breathing plasma engine and methods of operation are disclosed employing an arc plasma chamber that generates plasma, e.g., electrode-coupled, direct current plasma, via electrodes continuously fed by an electrode-feeding assembly. The plasma chamber can be implemented in any one of the stages following the compression stage and having high-pressure and high-velocity air flow, e.g., for a jet engine, turbojet engine, or rocket engine.

A Hall effect thruster arranged inside a wall and including a magnetic circuit and an electric circuit including an anode, a first cathode, and a voltage source. The magnetic circuit and the electric circuit are arranged in such a manner as to generate magnetic and electric fields around the wall. In every meridian section, the magnetic circuit presents an upstream magnetic pole and a downstream magnetic pole arranged at the surface of the wall and spaced apart from each other; and the anode and the first cathode are situated on either side of the upstream magnetic pole.