NASA tests 120kW lithium thruster

Electric propulsion is the class of space engine that trades brute-force shove for efficiency. You get much less thrust than a chemical rocket, but you can keep pushing for a long time and use far less propellant. That trade starts to look very attractive once you stop thinking about launch and start thinking about hauling cargo around deep space. That is why NASA’s latest test matters: on February 24, 2026, JPL fired a lithium-fed magnetoplasmadynamic thruster to 120 kilowatts, then published the result on April 28. ### What exactly did NASA test? NASA tested a prototype MPD thruster — short for magnetoplasmadynamic thruster — inside JPL’s condensable metal propellant vacuum facility in Southern California. This is not a flight engine. It is a ground prototype built to see whether a high-power electromagnetic thruster using lithium vapor can run cleanly at a much higher power level than the electric thrusters flying today. (nasa.gov) ### Why is “120 kilowatts” a big deal? Because electric propulsion power is the whole game. NASA said this was the first time in the U.S. that an electric propulsion system had operated at power levels this high, reaching up to 120 kW. For a rough sense of scale, NASA also said that is beyond the power level of the highest-power electric thrusters on any current agency spacecraft. (nasa.gov) ### How is this different from a normal ion engine? A normal ion or Hall thruster uses electric fields to accelerate a propellant like xenon. An MPD thruster leans harder on current and magnetism — basically, it drives a very high electrical current through plasma and uses the resulting magnetic interaction to fling that plasma out the back. Same family of idea, different regime. The point is to handle much higher power and, eventually, much bigger transport jobs. (nasa.gov) ### Why use lithium? Lithium is light, and that helps when the goal is very high exhaust velocity — the thing space engineers call specific impulse. JPL and NASA have been looking at lithium MPD concepts for decades, and older NASA mission studies explicitly modeled Mars cargo vehicles using lithium-propellant MPD thrusters. So this is not a random propellant choice. It fits a long-running architecture idea. (nasa.gov) ### Why does the test chamber matter so much? Because lithium vapor is messy in a way xenon is not. It condenses onto surfaces, contaminates hardware, and makes diagnostics harder. JPL’s CoMeT facility exists specifically to handle metal-vapor propellants safely and to support testing at power levels that could eventually reach the megawatt class. In other words, the chamber is part of the breakthrough. Without the chamber, you do not really get to test this kind of engine properly. (ntrs.nasa.gov) ### Did NASA just build a Mars engine? No — and this is the catch. A successful 120 kW firing is a component milestone, not a mission-ready propulsion system. NASA’s own Mars cargo studies looked at nuclear electric propulsion systems around 1.5 megawatts, which is more than an order of magnitude above this test. The gap from “worked in a chamber” to “reliable for years in space” is huge. (nasa.gov) ### So why does this still matter? Because high-power electric propulsion has been one of those technologies that always sounds plausible on paper but struggles to show real hardware progress. This test does not close the case, but it moves the conversation from old modeling and legacy concepts to fresh data from a real device. That is a meaningful shift. (ntrs.nasa.gov) ### What is the bottom line? NASA did not unveil a finished Mars drive. It proved that a lithium-fed MPD thruster can run at a record 120 kW in a U.S. test setup built for the ugly realities of metal-vapor propulsion. Basically, this is an early but real step toward the kind of electric propulsion heavy deep-space logistics would actually need. (nasa.gov)