The MPD thruster improvements described here apply to coaxial gas-fed quasisteady self-field devices without auxiliary magnetic fields.

Disclosed is a closed drift, narrow channel Hall thruster configured to operate at powers <30 W. The thruster includes a thruster body and a neutralizing cathode. The thruster body includes a magnetic circuit including a magnetic source and two magnetic poles, a metallic, annular thruster channel formed by the magnetic poles with a downstream channel width smaller than about 3 mm and an upstream channel width greater than the downstream channel width, an anode positioned at the channel's entry, and a gas distributor configured to release a propellant gas into the thruster channel. The magnetic circuit is configured to generate a magnetic field in the thruster channel for trapping electrons therein. The channel walls (the magnetic poles) are under bias potential. The anode and the cathode are configured to generate a substantially axial electric field in the thruster channel. In operation, propellant gas atoms ionized by trapped electrons in the thruster channel, accelerate axially, exiting via the channel's exit.

According to certain aspects, an electric-propulsion thruster is used as part of a base or platform which also includes a power converter, having a plurality of inductors and other electrical components, and a printed circuit board (PCB). The PCB includes a layer at which the other electrical components and printed circuit inductor traces, for the plurality of inductors, are secured. The electric-propulsion thruster includes a housing (e.g., as part of the base or platform) providing a cavity and having at least one structurally-rigid side wall along the cavity, where the PCB is integrated with the electric-propulsion thruster for a compact arrangement which can be used to propel the apparatus. Such a compact design might be used as an important part of thruster spacecraft architecture such as micro-satellites (e.g., CubeSats).

A thruster has a first stage and a second stage. The first stage is a plasma source that outputs a plasma. The second stage is an accelerator. In one embodiment, the second stage is a plasma accelerator that accelerates the plasma. In another embodiment, the second stage is an ion accelerator that accelerates the ions from the plasma.

A plasma reactor is provided together with a method for generating kinetic energy to propel a craft. The reactor includes an inlet for plasma; a reactor core having an interior chamber and an exterior chamber, the interior chamber being configured to rotate within the exterior chamber; a pair of opposing polar field generators, a first polar field generator connected proximal to an inlet of the interior chamber, and a second polar field generator connected proximal to an outlet of the interior chamber, the pair of polar field generators configured to induce a current in the plasma to generate a toroidal flow therein, wherein the toroidal flow compresses the plasma into a z-pinch flow in a central column between the first polar field generator and the second polar field generator; turbine blades located between the interior chamber and the exterior chamber for generating thrust to convert the z-pinch flow to kinetic energy; and an outlet.

A field emission propulsion system for a spacecraft includes a control unit, a propulsion assembly, and a plurality of extractor electrode voltage sources. The propulsion assembly comprises a plurality of field emission propulsion units having an ion source with a plurality of ion emitters and extractor electrodes associated with the ion emitters and disposed in a field arrangement. The plurality of extractor electrode voltage sources, each associated with the extractor electrodes to control the same, are controlled by the control unit using an individual extractor electrode voltage.

A method for providing optimized power balanced low thrust transfer orbits utilizing split thruster execution to minimize an electric orbit raising duration of an apparatus includes monitoring an electric power balance on the apparatus. The method also includes firing a first thruster in response to the apparatus exiting an eclipse and based on the electric power balance. The method additionally includes firing a second thruster at a predetermined time delay after firing the first thruster based on the electric power balance. The method additionally includes ending firing one of the first thruster or the second thruster after a predetermined time duration based on the electric power balance. The method further includes ending firing another of the first thruster or the second thruster in response to the apparatus entering a next eclipse.

A satellite having a longitudinally elongated body and being capable of operating in the thermosphere. The satellite can be powered by an electric rocket engine, and includes a remote sensing system configured to obtain images of Earth. An elongated axis about which the elongated body extends can be generally aligned with a forward direction of the satellite, with a viewing angle from the satellite oriented transverse to the elongated axis. A center of mass of the satellite can be forward of a center of drag to produce positive natural stability. The remote sensing system, which can be part of a payload, can include a movable mirror and one or more movable optical elements. A first mirror can be pivoted, and/or other optical elements, including the payload, can be rotated about the axis of the elongated body. Counter-acting masses can be used to null motion of the movable components.

Disclosed is a radio-frequency plasma generating system including a radio-frequency generator and a plasma source, the radio-frequency generator being inductively or capacitively coupled to the plasma source through a resonant electric circuit, the radio-frequency generator being adapted to receive direct current power from a direct current power supply and for generating radio-frequency power at a frequency f, the radio-frequency power including a reactive radio-frequency power oscillating in the resonant electric circuit and an active radio-frequency power absorbed by the plasma. The radio-frequency plasma generating system includes a unit for measuring an efficiency of conversion E of direct-current power to active radio-frequency power absorbed by the plasma and a unit for adjusting the frequency f as a function of the measured efficiency of conversion E to maintain the efficiency of conversion E in a predetermined range within a RF plasma operational range.

The present technology is directed to plasma systems and associated methods, including propulsion systems for flight vehicles. A representative system includes a plurality of coils. The coils include a first coil positioned along a force axis, a second coil positioned along the force axis and spaced apart from the first coil, and a third coil that is magnetically shielded. A controller is operatively coupled to the coils and is configured to (a) increase energy to the first coil to generate a magnetic field in a portion of the plasma adjacent to the first coil, (b) decrease energy to the first coil and increase energy to the second coil to translate the resulting superposed magnetic field through the plasma to a position adjacent the second coil, and (c) transfer energy from the second coil to the third coil and decrease energy to the second coil to reduce the magnetic field in the plasma.