JPL Tests Record-Breaking 120kW Lithium Electromagnetic Thruster

NASA’s **Jet Propulsion Laboratory (JPL)** has achieved a significant breakthrough in deep-space propulsion technology. Today, engineers successfully completed a full-duration test of a **120kW lithium-fed Magnetoplasmadynamic (MPD) thruster**. This engine is 25 times more powerful than the Hall-effect thrusters used on current deep-space probes and is a foundational technology for future crewed missions to Mars and the outer planets.

The Lithium Advantage

Most modern electric propulsion systems use xenon or krypton as propellant. While effective, these noble gases are expensive and difficult to store in large quantities for multi-year missions. The JPL team pivoted to **liquid lithium**. Lithium is abundant, can be stored as a solid at room temperature, and when vaporized, provides a significantly higher exhaust velocity than xenon. By using a lithium-fed architecture, the thruster achieves a specific impulse (efficiency) that could reduce the transit time to Mars by up to 30%, while requiring half the propellant mass of a xenon-based system.

The 120kW Power Threshold

Operating an MPD thruster at 120kW introduces extreme thermal and electromagnetic stress. Traditional electrodes would melt within minutes. The JPL breakthrough involves a **self-healing liquid lithium cathode**, where the lithium propellant itself acts as the electrode surface. As the lithium is ionized and accelerated by the magnetic field, it continuously refreshes the cathode, preventing erosion and allowing for thousands of hours of continuous operation. This "propellant-as-hardware" model is a radical departure from traditional ion engine design and is the key to achieving the power levels needed for massive cargo transports.

Pairing with Nuclear Fission

A 120kW thruster requires more power than current solar arrays can reliably provide at Mars's distance from the Sun. JPL is designing this engine to be paired with upcoming **Nuclear Fission Reactors** (like those being developed by NANO Nuclear or the DARPA DRACO program). A cluster of four 120kW lithium thrusters would provide the megawatt-scale propulsion needed to push a crewed habitat through interplanetary space at speeds previously only possible in science fiction. The first space-based test of a sub-scale lithium thruster is planned for 2028.

As we enter the era of **Interstellar Infrastructure**, the JPL milestone proves that the bottleneck to reaching Mars is no longer physics—it is simply a matter of power and propellant scaling. The lithium-fed MPD thruster is the "warp drive" of the 21st century, hidden in plain sight.