NASA Tests Lithium-Fed Electric Thruster for Future Mars Missions

NASA’s Jet Propulsion Laboratory has successfully tested a lithium-fed magnetoplasmadynamic (MPD) electric thruster at power levels reaching 120 kilowatts. The February 2026 test is part of NASA’s effort to develop high-power electric propulsion that could eventually support robotic spacecraft and human missions to Mars, with future versions targeted at 500 kilowatts to 1 megawatt per thruster.

Reaching Mars faster is not simply a matter of building a larger rocket.

Once a spacecraft leaves Earth, conventional chemical propulsion becomes increasingly inefficient for long-duration deep-space travel. Carrying enough propellant for every major maneuver can add substantial launch mass, while traditional propulsion systems are not designed to continuously accelerate a spacecraft for months.

NASA is therefore investigating another approach: high-power electric propulsion capable of providing relatively low but sustained thrust over long periods.

One of the agency’s latest tests involves an unusual propellant — lithium metal vapor.

In February 2026, NASA’s Jet Propulsion Laboratory fired a prototype lithium-fed magnetoplasmadynamic (MPD) thruster inside its Electric Propulsion Laboratory. The system reached up to 120 kilowatts, more than 25 times the power of the electric thrusters currently operating on NASA’s Psyche spacecraft.

The test does not mean a lithium-powered Mars engine is ready for flight. Instead, it marks an important ground demonstration of a technology NASA hopes could eventually become part of a much larger nuclear-electric propulsion system.

How a Lithium-Fed MPD Thruster Works

Electric propulsion works differently from the chemical engines used during launch.

Instead of producing thrust primarily by burning fuel and ejecting hot combustion gases, an electric propulsion system uses electrical energy to accelerate charged particles to very high velocities.

NASA’s lithium-fed system belongs to a class known as magnetoplasmadynamic thrusters.

Inside an MPD thruster, electrical current interacts with a magnetic field to accelerate plasma. In this case, the propellant is lithium that is converted into metal vapor and then ionized.

The resulting lithium plasma can be accelerated electromagnetically through the thruster, generating thrust.

The concept has been studied for decades, but NASA notes that MPD thrusters have not yet flown operationally. The challenge has been developing systems capable of operating at the extremely high power and thermal conditions required for practical missions.

NASA Reaches 120 Kilowatts

The February test provided NASA with its first opportunity in years to operate this type of electromagnetic thruster at such high power in the United States.

The prototype reached 120 kW during five ignitions.

That is more than 25 times the power of the electric propulsion system currently used by NASA’s Psyche spacecraft, which carries the agency’s highest-power electric thrusters currently operating in space.

The test also exposed the hardware to extreme temperatures.

A tungsten electrode at the center of the thruster reached more than 2,800 degrees Celsius during the firings.

Managing that heat is one of the central engineering challenges for future versions.

A propulsion system intended to operate continuously for thousands of hours cannot simply survive a short demonstration. Its electrodes, power systems, magnetic components and other hardware must maintain performance for long-duration operation.

Why Lithium?

Lithium offers several characteristics that make it interesting as a high-power electric-propulsion propellant.

NASA’s technical work identifies lithium-fed MPD systems as candidates for high-power nuclear-electric propulsion because they can potentially process large amounts of electrical power while maintaining relatively high propulsive performance.

The lithium is also condensable, which makes it possible to design specialized ground-testing systems for the metal-vapor propellant.

NASA’s propulsion research has explored lithium-fed MPD systems as a way of increasing thrust density compared with many conventional electric-propulsion approaches.

That matters because deep-space spacecraft cannot simply carry unlimited propulsion hardware.

A practical Mars system would need a combination of high power, manageable mass, sufficient thrust and long operating life.

Electric Propulsion Uses Less Propellant

The main advantage of electric propulsion is efficiency.

NASA states that electric propulsion can use up to 90% less propellant than traditional high-thrust chemical propulsion, although the trade-off is that electric thrusters generally produce much lower thrust.

That difference changes how a spacecraft travels.

A chemical rocket can generate enormous thrust for a relatively short period. An electric propulsion system can instead apply a smaller force continuously for much longer.

Over time, that persistent acceleration can produce very high spacecraft velocities.

NASA’s Psyche mission demonstrates the principle. Its electric thrusters provide low, continuous thrust that gradually accelerates the spacecraft through interplanetary space.

For future deep-space missions, the goal is to increase the available electric power enough to generate substantially more thrust while retaining the efficiency advantages of electric propulsion.

The Nuclear Connection

The lithium-fed thruster is being developed as part of NASA’s Space Nuclear Propulsion effort.

That connection is important because a high-power electric thruster needs a high-power electrical source.

Solar panels can provide substantial power near the Sun, but their effectiveness decreases as spacecraft travel farther away. For ambitious human missions to Mars and beyond, NASA is studying nuclear-electric propulsion as one possible solution.

In such a system, a nuclear power source would generate electricity, which would then operate high-power electric thrusters.

The propulsion system would not use the reactor to directly produce thrust. Instead, the reactor would provide the electrical power needed to accelerate the propellant.

That architecture could allow a spacecraft to carry a relatively efficient propulsion system while supplying it with continuous high-power energy.

NASA Wants to Scale the Thruster

The 120-kilowatt demonstration is only the starting point.

NASA and its partners are targeting 500 kilowatts to 1 megawatt per thruster in future development.

That is a substantial increase over the current prototype.

The agency estimates that a human Mars mission could potentially require 2 to 4 megawatts of propulsion power. Such a system could therefore require multiple MPD thrusters operating together.

But increasing power creates another problem: endurance.

NASA estimates that a Mars mission architecture using these thrusters could require operating times exceeding 23,000 hours.

That is more than 2.6 years of cumulative operation.

Demonstrating that the hardware can withstand those conditions is therefore one of the biggest remaining steps between a successful laboratory test and a viable flight system.

What It Could Mean for Robotic Missions

Human Mars missions are the most ambitious application being discussed, but robotic spacecraft could potentially benefit earlier.

High-power electric propulsion could be useful for missions requiring substantial changes in velocity while carrying significant scientific payloads.

Potential applications include faster transportation of robotic spacecraft to Mars, outer-planet missions, sample-return architectures and other deep-space exploration concepts.

NASA’s Jet Propulsion Laboratory describes advanced electric propulsion as an important technology for increasing the speed and range of future robotic exploration throughout the solar system.

For robotic missions, even a reduction in travel time could have significant scientific value.

A shorter cruise can reduce the time before a spacecraft reaches its target, potentially allowing missions to collect data sooner and reducing some operational constraints associated with very long journeys.

The Mars Advantage Comes With Trade-Offs

Electric propulsion should not be viewed as a direct replacement for chemical rockets.

Chemical propulsion remains essential for launching spacecraft from Earth and for missions requiring very high thrust over short periods.

Electric propulsion is most useful once a spacecraft is already in space and can spend extended periods accelerating.

The lithium-fed MPD concept is therefore better understood as part of a multi-stage transportation architecture.

A conventional launch vehicle could place a spacecraft into space.

A nuclear-electric system could then provide sustained propulsion for the long journey.

Additional propulsion systems could handle specialized maneuvers, landing operations or other situations where high thrust is required.

The Engineering Challenges Are Still Significant

The most important question now is not whether the lithium-fed thruster can fire.

NASA has demonstrated that.

The next questions involve efficiency, durability, thermal management, power conversion, magnetic-field control and long-duration operation.

The thruster must also be integrated with a complete propulsion system.

That means pairing it with power generation, energy conversion, thermal control, propellant storage and spacecraft structures.

A megawatt-class propulsion system would generate substantial waste heat, making thermal management particularly important.

The spacecraft would need to reject that heat continuously while operating far from Earth.

A Step Toward Faster Deep-Space Transportation

NASA’s February test represents a shift in scale for electric propulsion research.

Existing electric thrusters have already demonstrated that spacecraft can travel efficiently through deep space. The challenge is increasing their power and thrust without losing the efficiency that makes electric propulsion attractive.

The lithium-fed MPD approach is one possible route.

NASA’s prototype has already reached 120 kilowatts, and the agency is now looking toward systems operating in the hundreds of kilowatts and eventually the megawatt range.

There is still a long development path before such a propulsion system could fly on a human Mars mission.

But the objective is clear: develop propulsion capable of moving larger spacecraft and payloads through deep space while using propellant far more efficiently than conventional chemical systems.

For future Mars exploration, that could change how spacecraft are designed — not by replacing the rocket that leaves Earth, but by creating a powerful new way to travel after reaching space.

5 Most Searched FAQs

1. What is a lithium-fed thruster?

A lithium-fed thruster is an electric propulsion system that uses lithium metal vapor as its propellant. NASA is testing a magnetoplasmadynamic design that accelerates lithium plasma electromagnetically.

2. How powerful is NASA’s lithium-fed thruster?

NASA’s prototype reached 120 kilowatts during its February 2026 ground test. The agency is targeting future systems capable of approximately 500 kilowatts to 1 megawatt per thruster.

3. Could the lithium-fed thruster take humans to Mars?

It is being developed as a potential component of propulsion systems for future human Mars missions, but it is not currently a flight-ready Mars engine. NASA says substantial development and long-duration testing remain necessary.

4. Why is electric propulsion useful for deep-space missions?

Electric propulsion can use substantially less propellant than conventional chemical propulsion. Its limitation is low thrust, so it works best by applying thrust continuously over long periods rather than providing a short, powerful acceleration.

5. Why would NASA pair the thruster with nuclear power?

A megawatt-class electric propulsion system requires a large and continuous electrical power supply. Nuclear-electric propulsion could potentially provide that power farther from the Sun, where solar energy becomes less suitable for very high-power systems. NASA’s lithium-fed MPD work is part of its Space Nuclear Propulsion effort.