Abstract: Scalable power processing units (PPUs) for Hall-effect thrusters (HETs) and terrestrial systems are disclosed. A technique for current estimation may be employed on each output of parallel isolated discharge supply modules (DSMs) to force proper current/load sharing between the DSMs. A flyback power supply may be used that performs the dual functions of a cathode keeper plasma ignitor and sustainer. The flyback power supply may be tuned for a high no-load direct current (DC) output voltage to achieve cathode keeper ignition rather than requiring a separate ignitor supply, which reduces circuit complexity. To address requirements for higher voltage DC ignition than are achievable with a flyback power supply alone, a supplemental DC ignitor may be placed in parallel with the flyback power supply of some embodiments. Such simplified PPU architectures may provide a high efficiency, low part count, scalable architecture suitable for more compact and lower cost system designs.

Abstract: 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.

Abstract: It is disclosed herein an innovative concept for in-space propulsion for future Air Force, NASA and commercial systems having mass and power scalability over a wide range and using easily-handled advanced propellants. The invention combines the fields of microdischarge physics and nonequilibrium plasmadynamics to reduce dramatically the size of electric thrusters by 1-2 orders of magnitude, which when coupled with micronozzles that are electrically conducting or electrically insulating result in high thrust and high thruster efficiency, and will enable scalable, low-cost, long-life distributable propulsion for control of femtosats, picosats, nanosats, microsats, and space structures. The concept is scalable from power levels of 1 W to several kilowatts with thrust efficiency approaching 60%.

Abstract: A pulsed plasma thruster provides for an advanced lightweight design with solid propellant and predominately electromagnetic thrust in a coaxial geometry. Electromagnetic forces are generated in a plasma by current flowing from a small central electrode to an electrically conducting diverging nozzle electrode. The thruster employs a series of electric current pulses of limited duration and varying frequency between the pair of electrodes creating a series of electric arcs. The electric arcs pass over a propellant surface located between the electrodes, forming a plasma, which is then exhausted from the device to produce thrust. The thruster maintains a low plasma resistance and cavity pressure, which in turn yields strong electromagnetic body forces, resulting in a high efficiency and consistent pulse-to-pulse performance.

Abstract: A pulsed plasma thruster provides for an advanced lightweight design with solid propellant and predominately electromagnetic thrust in a coaxial geometry. Electromagnetic forces are generated in a plasma by current flowing from a small central electrode to an electrically conducting diverging nozzle electrode. The thruster employs a series of electric current pulses of limited duration and varying frequency between the pair of electrodes creating a series of electric arcs. The electric arcs pass over a propellant surface located between the electrodes, forming a plasma, which is then exhausted from the device to produce thrust. The thruster maintains a low plasma resistance and cavity pressure, which in turn yields strong electromagnetic body forces, resulting in a high efficiency and consistent pulse-to-pulse performance.