Development of a Prototype Model Ion Thruster for the NEXT System

Abstract

The NASA Evolutionary Xenon Thruster (NEXT) program, led by the NASA Glenn Research Center, is developing the next generation of ion thruster systems for solar system exploration. The team is led by NASA Glenn Research Center and includes Aerojet, the Jet Propulsion Lab, and Boeing. Aerojet is responsible for the development of the Prototype Model Electric Propulsion Thruster, the Engineering Model Propellant Management System, and the Digital Control Interface Unit simulator. The thruster has a 40cm beam diameter, providing twice the effective area of the NASA Solar electric propulsion Technology Application Readiness (NSTAR) thruster. All efforts have been made to preserve critical design heritage from NSTAR while also incorporating new technologies and processes to extend power, throttle range and throughput, reduce specific mass, and minimize cost. In Phase 1, NASA Glenn developed the Engineering Model thruster design, produced three thrusters, and conducted performance, wear, vibration and integration testing. This paper describes Aerojet's Phase 2 program to design, build and deliver two Prototype Model thrusters to support performance, environmental and system integration testing. The paper reviews the lessons learned and design heritage maintained from the NSTAR flight and extended life test units, and the Engineering Model NEXT thrusters. The principal design features of the Prototype Model NEXT thruster, discharge cathode and neutralizer cathode are outlined. Finally, the results of structural and thermal analysis are presented.