A new type of electromagnetic thruster has successfully completed an early test at NASA’s Jet Propulsion Laboratory (JPL), offering a glimpse of how astronauts could one day travel to Mars. If further developed, this technology could also power robotic missions across the solar system.
On Feb. 24, engineers at JPL in Southern California carried out a major test of the experimental engine, firing it at power levels higher than any similar test previously conducted in the United States. The thruster runs on lithium metal vapor and represents a significant step forward in electric propulsion.
This first test pushed the prototype beyond the capabilities of any electric thruster currently used on NASA spacecraft. The results are expected to guide a series of upcoming 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. The successful performance of our thruster in this test demonstrates real progress toward sending an American astronaut to set foot on the Red Planet,” said NASA Administrator Jared Isaacman. “This marks the first time in the United States that an electric propulsion system has operated at power levels this high, reaching up to 120 kilowatts. We will continue to make strategic investments that will propel that next giant leap.”
Extreme Heat and High Power Inside JPL’s Test Chamber
During five ignition cycles, the thruster’s central tungsten electrode heated up dramatically, glowing bright white at temperatures exceeding 5,000 degrees Fahrenheit (2,800 degrees Celsius). The test took place inside JPL’s Electric Propulsion Lab, which houses a specialized vacuum chamber designed to safely evaluate engines that use metal vapor propellants at extremely high power levels.
How Electric Propulsion Works
Electric propulsion systems are far more efficient than traditional chemical rockets, using up to 90% less propellant. Instead of producing a powerful burst of thrust, they generate a steady push over long periods, gradually accelerating spacecraft to very high speeds.
NASA’s current missions already rely on this approach. For example, the Psyche spacecraft uses solar-powered electric thrusters that provide continuous thrust, eventually reaching speeds of 124,000 mph.
The new engine being tested is a lithium-fed magnetoplasmadynamic (MPD) thruster. While the concept has existed since the 1960s, it has never been used operationally. Unlike existing systems, this design uses strong electrical currents and magnetic fields to accelerate plasma made from lithium, producing greater thrust at higher power levels.
Record Power Levels and Early Success
In this initial test, the thruster reached up to 120 kilowatts, more than 25 times the power of the engines currently flying on Psyche. That makes 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, senior research scientist at JPL. “It’s a huge moment for us because 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.”
Inside the Test: A Glowing Plasma Plume
Polk observed the test through a viewing port in a 26-foot-long (8-meter-long) water-cooled vacuum chamber. When activated, the thruster produced a bright, glowing plume as its outer electrode heated up and emitted a vivid red stream of plasma.
Polk has spent decades studying this type of propulsion, contributing to earlier missions such as Dawn and Deep Space 1, which demonstrated electric propulsion beyond Earth orbit for the first time.
Scaling Up for Human Missions to Mars
The next challenge is increasing the engine’s power even further. Researchers are aiming for levels between 500 kilowatts and 1 megawatt per thruster in the coming years. Because the system operates under extreme heat, engineers must prove it can run reliably for long periods.
A crewed mission to Mars could require between 2 and 4 megawatts of total power. That would likely involve multiple thrusters working together for more than 23,000 hours.
Why Lithium Plasma Thrusters Matter
Lithium-fed MPD thrusters offer several advantages. They can operate at very high power, use propellant efficiently, and produce more thrust than current electric propulsion systems. When paired with a nuclear power source, they could reduce the total mass needed for launch while enabling heavier payloads for human missions.
This combination could make long-duration missions to Mars more practical and cost-effective.
Collaboration and Future Development
Development of this thruster has been underway for the past 2½ years. The effort is led by JPL, working alongside Princeton University in New Jersey and NASA’s Glenn Research Center in Cleveland.
Funding comes from NASA’s Space Nuclear Propulsion project, which began in 2020 to advance key technologies needed for megawatt-class nuclear electric propulsion systems. The program is based at Marshall Space Flight Center in Huntsville, Alabama, and is part of NASA’s Space Technology Mission Directorate.