Title of Presentation: NEXT Ion Propulsion System Development Status and Capabilities

Primary (Corresponding) Author: Michael J. Patterson

Organization of Primary Author: NASA Glenn Research Center

Co-Authors: Scott Benson

Abstract:  The NASA Glenn Research Center is responsible for the development of NASA’s Evolutionary Xenon Thruster (NEXT) ion propulsion system.  The objective of the NEXT project is to advance next generation ion propulsion technology to NASA Technology Readiness Level (TRL) 5, with significant progress towards TRL 6.  The NEXT system consists of a high performance, 7-kW, ion thruster; a modular, 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. Technology validation and mission analysis results in Phase 1 indicated that the NEXT technologies have the capabilities that provide the expected benefits, and further development was warranted.

The NEXT thruster and other component technologies represent a significant advancement in technology beyond state-of-the-art NSTAR thruster systems.  NEXT performance exceeds single or multiple NSTAR thrusters over most of the thruster input power range.  Higher efficiency and specific impulse, and lower specific mass reduce the wet propulsion system mass and parts count.  The NEXT thruster xenon propellant throughout is more than twice NSTAR’s, so fewer thrusters are needed.  The NEXT power processor and propellant feed system technologies provide mass and performance benefits versus NSTAR.

As NASA’s Evolutionary Xenon Thruster technology program draws to its conclusion, it is advantageous to review the existing technology capabilities of the system under development.  This includes the thruster performance and throttling capabilities, the thruster lifetime, and the subsystem and system masses and power budgets.  This paper describes the NEXT ion propulsion system development status, characteristics and performance.  A review of mission analyses results conducted to date using the NEXT system is also provided.