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Hall, Scott

Publications and source records attributed to Hall, Scott.

Overview of NASA's Solar Electric Propulsion Project

NASA is continuing to develop and qualify a state of the art 13 kW-class Advanced Electric Propulsion System (AEPS) for NASA exploration missions through a contract with Aerojet Rocketdyne. An objective of the AEPS project is to empower the US space industry to accelerate the adoption of high power electric propulsion technologies by reducing the risk and uncertainty of integrating Solar Electric Propulsion (SEP) technologies into space flight systems. NASA and AEPS contract has recently initiated engineering hardware testing of the Hall Current Thruster (HCT), Power Processing Unit (PPU), and Xenon Flow Controller (XFC) at both the component and system levels. The successful completion of these tests will provide the required information to advance the AEPS system towards Critical Design Review. In support of the AEPS contract, NASA and JPL have been performing risk reduction activities to address specific concerns of the state of the art higher power Hall thruster propulsion system. These risk reduction activities have included long duration wear testing of the Technology Demonstration Unit (TDU) Hall thruster and cathode hardware, thermal cycling testing of TDU cathode heaters and coils, plasma plume measurements, and investigating PPU design. In addition to NASA propulsion development, the SEP project is developing the Plasma Diagnostic Package (PDP) and the SEP Testbed. The PDP is designed for use in conjunction with a high powered EP system to characterize in-space operation. The SEP Testbed system is developed for demonstration of Abstract: NASA is continuing to develop and qualify a state of the art 13 kW-class Advanced Electric Propulsion System (AEPS) for NASA exploration missions through a contract with Aerojet Rocketdyne. An objective of the AEPS project is to empower the US space industry to accelerate the adoption of high power electric propulsion technologies by reducing the risk and uncertainty of integrating Solar Electric Propulsion (SEP) technologies into space flight systems. NASA and AEPS contract has recently initiated engineering hardware testing of the Hall Current Thruster (HCT), Power Processing Unit (PPU), and Xenon Flow Controller (XFC) at both the component and system levels. The successful completion of these tests will provide the required information to advance the AEPS system towards Critical Design Review. In support of the AEPS contract, NASA and JPL have been performing risk reduction activities to address specific concerns of the state of the art higher power Hall thruster propulsion system. These risk reduction activities have included long duration wear testing of the Technology Demonstration Unit (TDU) Hall thruster and cathode hardware, thermal cycling testing of TDU cathode heaters and coils, plasma plume measurements, and investigating PPU design. In addition to NASA propulsion development, the SEP project is developing the Plasma Diagnostic Package (PDP) and the SEP Testbed. The PDP is designed for use in conjunction with a high powered EP system to characterize in-space operation. The SEP Testbed system is developed for demonstration of an integrated SEP end-to-end system performance. The paper will present an overview of the NASA and the AEPS contract activities and a summary of the associated NASA in-house activities.

Plasma Diagnostics Package

High Current Lanthanum Hexaboride Hollow Cathode for 20-200 kW Hall Thrusters

The demand for higher power Hall and ion thrusters continues for providing high thrust and long life for deep space mission. The X3 nested Hall thruster is capable of power levels in the 20 to 200-kW range, and is being developed by the University of Michigan and Aerojet for future cargo and manned-missions. The cathode for this thruster is required to produce discharge currents of 50 to 350 A with lifetimes in excess of 10 khrs. A high-current lanthanum hexaboride (LaB6) hollow cathode was previously developed at JPL for these applications, and was successfully operated at over 250 A of discharge current. An updated version of this cathode has been designed, built and tested at JPL, and then used to run the X3 nested Hall thruster at currents of up to 250 A. The new version is designed to reduced orifice plate overheating at high currents, and is capable of injecting auxiliary gas directly into the near-cathode plume from two locations to minimize energetic ion generation at high current. The cathode is predicted to be capable of producing over 350 A of discharge current, and has been tested to date at JPL at steady-state discharge currents from 25 A to 300 A.

Goebel, Dan M.

100 kW Nested Hall Thruster System Development

Large scale cargo transportation to support human missions to the Moon and Mars will require very high power Solar Electric Propulsion (SEP) systems operating between 200 and 400 kW. Aerojet Rocketdyne's NextSTEP program is developing and demonstrating a 100 kW EP system, the XR-100, using a Nested Hall Thruster (NHT) designed for powers up to 200 kW, a modular power processor and a modular flow controller. The three year program objective is to operate the integrated EP system continuously at 100 kW for 100 h, advancing this very high power Electric Propulsion (EP) system to Technology Readiness Level (TRL) 5. With our University of Michigan, Jet Propulsion Laboratory and NASA Glenn Research Center teammates, Aerojet Rocketdyne has completed the initial phase of the program, including operating the thruster at up to 30 kW to validate the thermal models and developing and operating multiple power processor modules in the required seriesparallel configuration. The current phase includes completing a TRL 4 integrated system test at reduced power to validate all system operating phases. Design upgrades to demonstrate the TRL 5 capabilities are underway. This paper will present the high power XR-100 capabilities, overall program and design approach and the latest test results for the 100 kW EP system demonstration program.

Jackson, Jerry