NASA fires lithium-vapor thruster at record U.S. power in step toward Mars missions

NASA’s Jet Propulsion Laboratory has fired an experimental electromagnetic thruster at record power levels for a U.S. test, a milestone researchers say could shape future deep-space travel and, eventually, crewed missions to Mars. On Feb. 24 in Southern California, engineers at JPL ran the lithium-fed prototype at up to 120 kilowatts, surpassing the capabilities of any electric thruster currently flying on NASA spacecraft.

The engine, a magnetoplasmadynamic (MPD) thruster, runs on lithium metal vapor. During five ignition cycles inside JPL’s Electric Propulsion Lab, its central tungsten electrode glowed bright white as temperatures exceeded 5,000 degrees Fahrenheit (2,800 degrees Celsius).

The test was conducted in a 26-foot-long (8-meter-long), water‑cooled vacuum chamber designed to safely evaluate high-power systems that use metal vapor propellants. Results from the firing are expected to guide a series of experiments aimed at refining and scaling the technology.

“At NASA, we work on many things at once, and we haven’t lost sight of Mars,” NASA Administrator Jared Isaacman said, calling the run the first time in the United States that an electric propulsion system has operated at power levels this high, reaching up to 120 kilowatts.

He said the agency will continue to make strategic investments to enable the next leap in exploration. Electric propulsion trades brute-force thrust for efficiency, using up to 90% less propellant than chemical rockets while delivering a steady push over long periods.

NASA already employs the approach: the Psyche spacecraft’s solar-powered electric thrusters provide continuous acceleration, with the mission expected to reach speeds of about 124,000 mph. The MPD concept, studied since the 1960s but not used operationally, uses strong electrical currents and magnetic fields to accelerate lithium plasma, enabling higher thrust at higher power levels.

In this initial run, the JPL thruster’s 120-kilowatt operation was more than 25 times the power of the engines currently flying on Psyche, making it the highest-power electric propulsion system tested in the United States to date. “Designing and building these thrusters over the last couple of years has been a long lead-up to this first test,” said James Polk, a senior research scientist at JPL.

“We not only showed the thruster works, but we also hit the power levels we were targeting. And we know we have a good testbed to begin addressing the challenges to scaling up.” Polk watched the firing through a viewing port as the thruster produced a bright plume.

The outer electrode heated up and emitted a vivid red stream of plasma—visual confirmation of the system’s extreme operating conditions. Polk has spent decades advancing electric propulsion, including on missions such as Deep Space 1 and Dawn, which proved the technology beyond Earth orbit.

The next phase focuses on pushing the power even higher—toward 500 kilowatts to 1 megawatt per thruster in the coming years—while proving the engine can run reliably for long durations under intense heat. JPL’s team plans additional tests to tackle those challenges, with the goal of maturing a system that could one day propel heavy robotic spacecraft and, potentially, support crewed voyages to Mars.