A team of engineers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif, successfully tested a new ion propulsion engine design, one of several candidate propulsion technologies under study by NASA’s Project Prometheus. The event marked the first performance test of the Nuclear Electric Xenon Ion System (NEXIS) engine at the high- efficiency, high-power, and high-thrust operating conditions needed for use in large-scale nuclear electric propulsion applications.