The NASA Evolutionary Xenon Thruster (NEXT): The NEXT Step for U.S. Deep Space Propulsion
- Paper number
IAC-08.C4.4.2
- Author
Dr. George Schmidt, NASA Glenn Research Center, United States
- Year
2008
- Abstract
NASA’s Evolutionary Xenon Thruster (NEXT) project is developing next generation ion propulsion technologies to provide future NASA science missions with enhanced mission performance at a low total development cost. The objective is to advance ion propulsion technology by producing engineering model and prototype model system components, validating these through qualification-level and integrated system testing, and ensuring preparedness for transitioning to flight system development. The project will culminate in mid-2008 with an integrated system demonstration in a simulated space environment. This will effectively demonstrate a technological readiness level (TRL) of 6 (i.e., demonstrated operation of a prototypical system in a representative environment), and will provide formal evidence that NEXT is ready for flight. NASA’s Science Mission Directorate funds the NEXT project under its In-Space Propulsion Technology Program (ISPT). The project team is led by NASA Glenn Research Center (GRC). Other team members include the Jet Propulsion Laboratory (JPL), Aerojet, L3 Communications, and ATK (formerly Swales). NEXT was implemented through a competitively-selected NASA Research Announcement (NRA) awarded in 2002 with the first phase completed in August 2003. Technology validation and mission analysis results from this phase confirmed the merits and benefits of continued NEXT technology development. The second phase of the project was initiated in October 2003 and is now approaching the final phase of activities. The NEXT system elements include 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) consisting of a single High Pressure Assembly (HPA) and one Low Pressure Assembly (LPA) per thruster; 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 at a low total development cost. The NEXT thruster and other component technologies represent a significant advancement over state-of-the-art (SOA), which for the U.S. is represented by the NASA Solar Electric Propulsion Technology Application Readiness (NSTAR) thruster. 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 throughput capability 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. The NEXT project has also placed particular emphasis on configuration and design rigor to facilitate the transition of NEXT elements to flight. The project adopted this approach in order to avoid the difficulties encountered in implementing the NSTAR system on the recently launched Dawn mission, and to reduce future cost uncertainties. In general, NEXT technology is applicable to a wide range of NASA science mission programs, including small Discovery-class, medium New Frontiers-class and large Flagship-class missions. NEXT also offers advantages for many earth-space commercial and other missions of national interest. In summary, the NEXT project - at the completion of 2007 – should be in a high state of technical readiness to support Announcement of Opportunities (AO) for new Discovery- and New Frontier-class missions in 2008 and beyond. Functional and qualification-level environmental testing of key system elements are scheduled to be completed; the thruster life test should exceed the throughput demonstrated on the NSTAR thruster; and system integration testing with the most mature hardware products will be drawing to a close.
- Abstract document
- Manuscript document
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