The Elements of Innovation Discovered
Metal Tech News – April 28, 2026
NASA’s February test pushed the lithium-fed MPD thruster to 120 kilowatts, more than 25 times Psyche’s electric thrusters.
JPL’s CoMeT vacuum facility can safely test metal-vapor electric thrusters at power levels that could eventually reach megawatt range.
Bringing electric propulsion closer to the power levels needed for human travel to Mars, NASA April 28 announced that its Jet Propulsion Laboratory fired a prototype lithium-fed electromagnetic thruster at up to 120 kilowatts inside a specialized test chamber in Southern California.
Tested Feb. 24 at power levels beyond any previous U.S. firing of its kind, the lithium-fed magnetoplasmadynamic (MPD) thruster reached more than 25 times the power of the electric thrusters now flying on NASA’s Psyche spacecraft, which currently operates the highest-power electric thrusters of any NASA mission.
Built around lithium metal vapor rather than the chemical propellants used in conventional rockets, the JPL prototype is aimed at one of the central challenges of deep-space travel: moving large spacecraft efficiently enough to make future crewed Mars missions more practical.
Though electric propulsion is not new to NASA, the technology works much differently than chemical rockets, using power to accelerate propellant and produce a gentle but steady push that, over time, can build extraordinary speed without burning through fuel in a short, powerful burst.
On Psyche, that low continuous thrust is capable of accelerating the spacecraft to 124,000 mph (200,000 km\/h) in the vacuum of space.
Compared with traditional high-thrust chemical rockets, electric propulsion can use up to 90% less propellant. For missions that must travel millions of miles, carry heavy payloads, and leave room for life-support systems, crew systems, and return-trip requirements, that difference becomes more than an engineering preference.
The problem is power.
Current spacecraft electric thrusters operate at relatively low power levels, making them useful for robotic missions but far below what would be needed to move the mass required for human expeditions to Mars.
To close that gap, NASA has been developing nuclear electric propulsion, a system in which a nuclear power source would generate electricity for high-power electric thrusters capable of pushing large spacecraft through deep space.
For this to work at that scale, however, the propulsion system would still need thrusters capable of handling far more electricity than current flight systems and converting it into sustained thrust.
That is the role NASA is trying to give lithium-fed MPD thrusters.
Researched since the 1960s but never flown operationally, lithium-fed MPD thrusters move beyond the lower-power electric propulsion systems now flying on solar-powered spacecraft by sending high electrical currents through lithium vapor, turning it into plasma that is accelerated by the interaction between the current and a magnetic field.
“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.”
JPL’s CoMeT vacuum facility can safely test metal-vapor electric thrusters at power levels that could eventually reach megawatt range.
During five ignitions, the tungsten electrode at the center of the thruster glowed bright white, reaching more than 5,000 degrees Fahrenheit (2,800 degrees Celsius), while the nozzle-shaped outer electrode became incandescent and emitted a red plume inside the 26-foot-long (8-meter-long) water-cooled vacuum chamber.
That chamber, located inside JPL’s Electric Propulsion Lab, is part of the condensable metal propellant vacuum facility, a national asset designed to safely test electric thrusters using metal vapor propellants at power levels that could eventually reach the megawatt class.
Because lithium-fed MPD thrusters operate at temperatures and power levels far beyond current flight systems, the first test was less about proving a finished Mars engine than establishing that the hardware works and that JPL has a testbed capable of pushing the technology forward.
“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.”
Having researched lithium-fed MPD thrusters for decades, Polk also worked on NASA’s Dawn mission and Deep Space 1, the first demonstration of electric propulsion beyond Earth orbit.
At the scale NASA is now pursuing, the team aims to move from the 120-kilowatt firing to between 500 kilowatts and 1 megawatt per thruster, while a human mission to Mars could require 2 to 4 megawatts of power across multiple MPD thrusters operating for more than 23,000 hours.
With components running at extreme temperatures and Mars-class propulsion requiring years of cumulative operating time, the team must show that the thruster can withstand not just brief firings, but extended operation over the kind of timescale a crewed mission would demand.
Fully developed and paired with a nuclear power source, lithium-fed MPD thrusters could help reduce launch mass while supporting the larger payloads required for human Mars missions.
While Mars remains the central target, the same class of high-power propulsion could eventually support robotic spacecraft traveling throughout the solar system.
For now, the first firing gives NASA something it has not had before in the U.S. \u2013 a working electric propulsion system operating at the kind of power level needed to begin bridging the gap between today’s robotic electric thrusters and tomorrow’s nuclear-powered Mars spacecraft.<\/p>\n