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An Overview of Recent Developments in Electric Propulsion for NASA Science Missions

The primary source of electric propulsion development throughout NASA is managed by the in-space propulsion technology project at the NASA Glenn Research Center for the Science Mission Directorate. The objective of the electric propulsion project area is to develop near-term electric propulsion technology to enhance or enable science mission while minimizing risk and cost to the end user. Major hardware tasks include developing NASA's evolutionary xenon thruster (NEXT), developing a long-life high voltage hall accelerator (HIVHAC), developing an advanced feed system, and developing cross-platform components. The objective of the NEXT task is to advance next generation ion propulsion technology readiness. The NEXT system consists of a high-performance, 7-kW ion thruster; a high-efficiency, 7-kW power processor unit (PPU); a highly flexible advanced xenon propellant management system (PMS); a lightweight engine gimbal; and key elements of a digital control interface unit (DCIU) including software algorithms. This design approach was selected to provide future NASA science missions with the greatest value in mission performance benefit at a low total development cost. The objective of the HIVHAC task is to advance the Hall thruster technology readiness for science mission applications. The task seeks to increase specific impulse, throttle-ability and lifetime to make Hall propulsion systems applicable to deep space science missions. The primary application focus for the resulting Hall propulsion system would be cost-capped missions, such as competitively- selected, Discovery-class missions. The objective of the advanced xenon feed system task is to demonstrate novel manufacturing techniques that will significantly reduce mass, volume, and footprint size of xenon feed systems over conventional feed systems. The task has focused on the development of a flow control module, which consists of a three-channel flow system based on a piezo-electrically actuated valve concept. Component standardization and simplification are being investigated through the standard architecture task to reduce first user costs for implementing electric propulsion systems. Progress on current hardware development, recent test activities and future plans are discussed.