Methods and apparatuses for emitting electrons from a hollow cathode are provided. The cathode includes a plasma holding region configured to hold a plasma, a gas supply source configured to supply gas to the plasma holding region, and an orifice plate disposed on a periphery of the plasma holding region. The orifice plate comprises a plurality of openings constructed to receive electrons from the plasma. The plurality of openings decouple gas conductance and electrical conductance across the orifice plate. The diameters of the plurality of openings are within a range of 20%-60%, inclusive, of a diameter of a circular opening with an area equal to a sum of the areas of the plurality of openings.

Disclosed is a miniaturized plasma propulsion device with minimized surface area of the thruster walls exposed to the plasma and, as a result, reduced plasma-surface interactions including a set of segmented electrodes to facilitate the following improvements compared to relevant existing technologies: 1) control of the plasma flow including focusing of the plasma plume 2) increase of the thrust 2) reduction of inefficiencies associated with the electron cross field current, and 3) mitigation of low frequency oscillations. The electrodes affect all these actions when a DC or modulated voltage is applied to one or all of them with the same or different amplitudes, with the same or different frequencies or phases which are all optimized to realize the best performance through changes in the acceleration and/or ionization regions. In addition, the applied voltage to the main electrodes may also be modulated.

Systems and methods for embedding a thermal management system in an electric propulsion (EP) system is presented. According to one aspect, one or more oscillating heat pipes (OHPs) are provided within functional elements of the EP system. Each OHP includes channel segments that include a sealed working fluid. The channel segments are joined to form a continuous serpentine channel with a channel path that alternates between hot and cold regions of the EP system. According to another aspect, the functional elements of the EP system are reduced to a single monolithic structure with an embedded OHP. The single monolithic structure may be a single material or a multi material. According to yet another aspect, the functional elements are elements of a magnetic circuit of the EP system, including one or more of a backplate, an outer pole, an inner pole, or a center pole.

High propellant throughput Hall-effect thrusters (HETs) and components thereof are disclosed. A compact and high propellant throughput HET has an improved magnetic circuit that mostly shields the discharge chamber walls from high-energy ionized propellant, low-profile sacrificial pole covers to delay magnetic pole erosion, a unique discharge chamber subassembly, a mechanically crimped cathode emitter retainer to increase efficiency, a center-mounted hollow cathode, or a combination thereof. Such feature(s) may balance propellant throughput and thruster performance, minimize the volume of the thruster envelope, and/or simplify the thruster assembly.

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 Hall thruster includes an annular discharge region and an annular cathode concentric to the annular discharge region.

A heater for a hollow cathode and a method for manufacturing the heater for the hollow cathode are provided. An example heater includes a tube and a thickening located at an edge of the tube. The tube has a side wall of a predetermined thickness and a cut in the side wall. The thickening is configured for attaching two electrical current leads. The tube and the thickening are made of a carbon fiber composite.

A Hall-effect thruster assembly includes a plurality of magnetic sources for creating a magnetic circuit. The plurality of magnetic sources are positioned between a first end and a second, opposite end of the Hall-effect thruster. The plurality of magnetic sources define a longitudinal axis extending through the first end and the second end. The first end is configured as a discharge end. A mount assembly is coupled to the second end. The mount assembly is configured to secure the plurality of magnetic sources to a spacecraft. A magnetic element is supported by the mount assembly. The magnetic element is positioned relative to the plurality of magnetic sources by the mount assembly.

The invention relates to a field coil (18, 20), in particular for a satellite hall-effect plasma thruster, said field coil (18, 20) comprising a core (22) on which a conductor (24) is wound, characterized in that the conductor comprises an inorganic insulation cable (26) impregnated with a high-temperature-resistant silicone coating (32).

A propulsion system for a spacecraft includes a thrust generator for producing thrust to move the spacecraft. A propellant storage unit is in fluid communication with the thrust generator. A control assembly is in communication with the spacecraft. The control assembly includes a propellant management assembly configured to adjust a supply of propellant from the storage unit to the thrust generator. A controller is configured to control the propellant management assembly. The control assembly is configured to selectively operate the thrust generator in a first mode in which the thrust generator uses propellant to electrostatically generate thrust, and a second mode in which the thrust generator uses propellant to gas-dynamically generate thrust.