Abstract: Elements formed from magnetic materials and their methods of manufacture are presented. Magnetic materials include a magnetic alloy material, such as, for example, an Fe-Co alloy material (e.g., the Fe-Co-V alloy Hiperco-50(R)). The magnetic alloy materials may comprise a powdered material suitable for use in additive manufacturing techniques, such as, for example direct energy deposition or laser powder bed fusion. Manufacturing techniques include the use of variable deposition time and energy to control the magnetic and structural properties of the materials by altering the microstructure and residual stresses within the material. Manufacturing techniques also include post deposition processing, such as, for example, machining and heat treating. Heat treating may include a multi-step process during which the material is heated, held and then cooled in a series of controlled steps such that a specific history of stored internal energy is created within the material.

Abstract: Systems and methods for providing a heaterless hollow cathode for use in electric propulsion devices is presented. According to one aspect the cathode includes a thermionic emitter having a constricted upstream inlet compared to a downstream outlet of the emitter. The emitter is arranged downstream a hollow cathode tube. Constriction of the upstream inlet is provided by an inner cylindrical hollow space at an upstream region of the emitter having a diameter that is smaller compared to a diameter of an inner cylindrical hollow space at a downstream region of the emitter. A hollow transition region having a varying diameter connects the upstream region to the downstream region. According to another aspect, a ratio of the diameters of the two cylindrical hollow spaces reduces penetration of electric field, and therefore of electric discharge, into the upstream region of the emitter during operation.

Abstract: A flying capacitor multilevel (FCML) converter including a gate driver circuit comprising a DC-DC flyback converter having a plurality of isolated outputs. In various examples, the FCML circuit further includes a first control circuit connected to the FCML circuit determining the load current associated with a desired power output from the load; and determining a desired output voltage associated with the load current; a second control circuit that drives an inductor current (IL) through the inductor so that the output applies an output voltage comprising the desired output voltage; and a third control circuit obtaining a comparison of an average of the inductor current (IL) through the inductor with a predetermined reference current (ILREF) and setting the duty cycle so that the average does not exceed the predetermined reference current. Also described is the converter driving a load comprising a plasma and a propulsion system comprising the converter.

Abstract: Elements formed from magnetic materials and their methods of manufacture are presented. Magnetic materials include a magnetic alloy material, such as, for example, an Fe-Co alloy material (e.g., the Fe-Co-V alloy Hiperco-50(R)). The magnetic alloy materials may comprise a powdered material suitable for use in additive manufacturing techniques, such as, for example direct energy deposition or laser powder bed fusion. Manufacturing techniques include the use of variable deposition time and energy to control the magnetic and structural properties of the materials by altering the microstructure and residual stresses within the material. Manufacturing techniques also include post deposition processing, such as, for example, machining and heat treating. Heat treating may include a multi-step process during which the material is heated, held and then cooled in a series of controlled steps such that a specific history of stored internal energy is created within the material.

Abstract: Elements formed from magnetic materials and their methods of manufacture are presented. Magnetic materials include a magnetic alloy material, such as, for example, an Fe—Co alloy material (e.g., the Fe—Co—V alloy Hiperco-50®). The magnetic alloy materials may comprise a powdered material suitable for use in additive manufacturing techniques, such as, for example direct energy deposition or laser powder bed fusion. Manufacturing techniques include the use of variable deposition time and energy to control the magnetic and structural properties of the materials by altering the microstructure and residual stresses within the material. Manufacturing techniques also include post deposition processing, such as, for example, machining and heat treating. Heat treating may include a multi-step process during which the material is heated, held and then cooled in a series of controlled steps such that a specific history of stored internal energy is created within the material.

Abstract: Systems and methods for providing a heaterless hollow cathode for use in electric propulsion devices is presented. According to one aspect the cathode includes a thermionic emitter having a constricted upstream inlet compared to a downstream outlet of the emitter. The emitter is arranged downstream a hollow cathode tube. Constriction of the upstream inlet is provided by an inner cylindrical hollow space at an upstream region of the emitter having a diameter that is smaller compared to a diameter of an inner cylindrical hollow space at a downstream region of the emitter. A hollow transition region having a varying diameter connects the upstream region to the downstream region. According to another aspect, a ratio of the diameters of the two cylindrical hollow spaces reduces penetration of electric field, and therefore of electric discharge, into the upstream region of the emitter during operation.

Abstract: A flying capacitor multilevel (FCML) converter including a gate driver circuit comprising a DC-DC flyback converter having a plurality of isolated outputs. In various examples, the FCML circuit further includes a first control circuit connected to the FCML circuit determining the load current associated with a desired power output from the load; and determining a desired output voltage associated with the load current; a second control circuit that drives an inductor current (IL) through the inductor so that the output applies an output voltage comprising the desired output voltage; and a third control circuit obtaining a comparison of an average of the inductor current (IL) through the inductor with a predetermined reference current (ILREF) and setting the duty cycle so that the average does not exceed the predetermined reference current. Also described is the converter driving a load comprising a plasma and a propulsion system comprising the converter.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Elements formed from magnetic materials and their methods of manufacture are presented. Magnetic materials include a magnetic alloy material, such as, for example, an Fe—Co alloy material (e.g., the Fe—Co—V alloy Hiperco-50®). The magnetic alloy materials may comprise a powdered material suitable for use in additive manufacturing techniques, such as, for example direct energy deposition or laser powder bed fusion. Manufacturing techniques include the use of variable deposition time and energy to control the magnetic and structural properties of the materials by altering the microstructure and residual stresses within the material. Manufacturing techniques also include post deposition processing, such as, for example, machining and heat treating. Heat treating may include a multi-step process during which the material is heated, held and then cooled in a series of controlled steps such that a specific history of stored internal energy is created within the material.

Abstract: 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.

Abstract: Magnetically shielded miniature Hall thrusters are disclosed that use a unique magnetic field topology that prevents the magnetic field lines from intersecting the discharge channel walls in the acceleration region of the thruster. Instead, the lines of force originating from both the inner and outer pole pieces curve around the downstream edges of the discharge channel and follow the channel walls towards the anode. This unique field topology results in low electron temperature at the discharge channel walls while eliminating strong electric field components that would otherwise lead to high erosion rates and power deposition from ion acceleration into the channel walls.