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.

A low-power Hall thruster gains significantly improved efficiency by a combination of features, including a single piece, h-shaped magnetic screen which enables a more efficient internal volume utilization as well as optimal magnetic shielding; an internally mounted cathode with varying diameter further decreases the footprint of the thruster; an anode with multiple baffles connected by axially oriented holes generates a highly azimuthally uniform propellant flow.

A heaterless hollow cathode with high current discharge capability for use in electric propulsion devices is presented. The heaterless hollow cathode includes a thermionic emitter insert having a tubular shape and arranged inside a hollow cathode tube. The heaterless hollow cathode further includes a propellant feed tube that longitudinally extends from an upstream region of the hollow cathode tube into an inner volume of the insert. According to one aspect, an extension of the propellant feed tube into the inner volume of the insert is in a range from one quarter to three quarters of a total longitudinal length of the insert. The propellant feed tube is made of a refractory metal that is capable of withstanding temperatures above 2200 degrees C. with negligible evaporation. According to another aspect, the refractory metal is tantalum or tungsten.

A narrow channel Hall thruster comprising a thruster body with a magnetic circuit, an annular thruster channel having a channel width of less than 3 mm formed within the magnetic circuit, an annular anode, a cathode positioned externally to the thruster, and configured for electron emission, a power supply applying a positive potential to the anode, such that a plasma discharge can be generated in the annular thruster channel, and another power supply applying a negative potential to the cathode, relative to the thruster body and the anode. The second power supply reduces its negative voltage output to the cathode when the current supplied by the anode power supply exceeds a predetermined level, indicating that the discharge has reached a stable initiated condition. The reduction of the voltage output of the second power supply can be achieved either by self-regulation, or by use of a current limit circuit.

A low-power Hall thruster gains significantly improved efficiency by a combination of features, including a single piece, h-shaped magnetic screen which enables a more efficient internal volume utilization as well as optimal magnetic shielding; an internally mounted cathode with varying diameter further decreases the footprint of the thruster; an anode with multiple baffles connected by axially oriented holes generates a highly azimuthally uniform propellant flow.

An electric power supply system for a Hall effect electric thruster. The Hall effect electric thruster includes an anode, a cathode, a heater for the cathode and an igniter. The electric power supply system includes a first power supply source to power the anode, a second power supply source to power the heater and a power supply unit to electrically supply the igniter. The power supply unit includes a third power supply source and a passive electric circuit. The third power supply source powers the passive electric circuit and is configured to generate a voltage in the form of at least one pulse.

A Hall-effect thruster (10), configured to be arranged inside or outside a spacecraft. The thruster has a concentrator (36) for collecting particles (P). The shape of the concentrator is defined by a continuous contour (C1) wrapped around the thrust axis and is such that on a major portion of the contour, each section of the concentrator perpendicular to the contour has a parabolic shape and has a focus (F1) belonging to the contour (C1). In addition, the magnetic circuit (50) is arranged so as to generate the magnetic field (B) in the vicinity of the contour (C1).

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.

A method for controlling the temperature of an electric propulsion system. The electric propulsion system includes a discharge channel, an anode, a cathode, an injection system and a magnetic circuit. The injection system injects propellant gas into the discharge channel and the magnetic circuit has at least one magnetic winding to generate a magnetic field in the discharge channel. The temperature at a reference thermal point of the electric propulsion system is determined. The electric propulsion system is heated by the Joule effect by applying a current to the magnetic circuit when the determined temperature is below a minimum temperature predetermined during a stop phase of the electric propulsion system.

System (300, 400) and methods (500) for testing a reaction thruster (100) in a vacuum environment. The methods comprise: disposing the reaction thruster in a vacuum chamber which is at least partially connected to earth ground; removing at least one gas from the vacuum chamber to provide the vacuum environment; operating the reaction thruster so as to create a beam of electrons; and/or electrically isolating the electrons of the beam from at least one electrically conductive surface of the vacuum chamber. The electrical isolation can be achieved by applying an electrical bias voltage to the beam via an electrode. The electrode may comprise a conductive object disposed in the vacuum chamber and/or at least a portion of a vacuum chamber wall. In all cases, the electrode is electrically isolated from a portion of the vacuum chamber that is connected to ground.