A team from NASA’s Jet Propulsion Laboratory (JPL), in collaboration with researchers from Princeton University and NASA’s Glenn Research Center in Cleveland, has announced the successful test of a prototype advanced electric thruster propulsion system 25 times more powerful than the electric thruster powering NASA’s Psyche mission.
According to a JPL statement announcing the achievement, “for the first time in years and at power levels exceeding any previous test in the United States,” the team successfully engaged a magnetoplasmadynamic (MPD) thruster that uses lithium metal vapor as a propellant. The JPL team said that the prototype electric thruster, which could one day carry humans to Mars, achieved power levels “beyond the highest-power electric thrusters on any of the agency’s current spacecraft,” while also providing researchers with valuable data on the sci-fi-sounding technology.
“This marks the first time in the United States that an electric propulsion system has operated at power levels this high,” said NASA Administrator Jared Isaacman of the successful test, which is part of the agency’s Space Nuclear Propulsion (SNP) program. “We will continue to make strategic investments that will propel that next giant leap.”
NASA JPL’s Prototype Electric Thruster Propulsion System 25X More Powerful Than Psyche
During a series of five ignitions at JPL’s Electric Propulsion Lab, which houses the condensable metal propellant vacuum facility where electric thrusters that use metal propellants can be tested safely, the MPD thruster’s tungsten electrode reached over 5,000 degrees Fahrenheit (2,800 degrees Celsius).
Thanks to the facility’s high-energy capacity, the team achieved power levels of “up to 120 kilowatts.” As noted, that exceeds the highest power output of any electric thrusters of any NASA spacecraft, including the advanced propulsion system currently powering Psyche past 124,000 mph via a small yet steady force.
“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.”
Magnetoplasmadynamic Thruster Accelerates Liquid Metal Lithium Plasma
The current crop of electric propulsion thrusters uses energy collected from the Sun to accelerate small amounts of propellant. This small but steady expulsion of ionized gas produces a low, continuous thrust that can reach speeds well beyond those of conventional chemical rockets, given enough time.
The MPD technology featured in the latest tests has been researched since the 1960s. According to the JPL team’s statement, the MPD thrusters differ from existing thrusters by using high currents to interact with a magnetic field and electromagnetically accelerate lithium plasma, resulting in a minute yet significant thrust. Still, according to the JPL statement, the lithium-fed thruster has “never flown operationally.”
NASA is exploring electric propulsion, including MPD technology, due to its significant cost savings over conventional rockets. The JPL team said that these devices can use “up to 90% less propellant” than traditional, high-thrust chemical rockets used to escape Earth’s gravitational pull. As part of the agency’s original Dawn and Deep Space-1 missions. Polk has translated that experience in electric propulsion into the development of lithium-fed MOD thrusters.
“Lithium-fed MPD thrusters have the potential to operate at high power levels, use propellant efficiently, and provide significantly greater thrust than currently flying electric thrusters,” the team explained. “Fully developed and paired with a nuclear power source, they could reduce launch mass and support payloads required for human Mars missions.”
“We Haven’t Lost Sight of Mars”
Moving forward, the JPL-led team said the high temperatures emitted by MPD thrusters during their tests will make providing ruggedized components capable of withstanding them “a key challenge.” They will also use the coming years to pursue power levels “between 500 kilowatts and 1 megawatt per thruster.”
Because engineers have projected that a Mars mission could require anywhere from two to four megawatts of power to reach the planet in a proper time, a final spacecraft design may incorporate multiple MPD thrusters capable of operating “for more than 23,000 hours” straight.
When discussing the successful electric propulsion thruster test, Isaacman said it demonstrates “real progress” toward the agency’s long-term goal of sending an American astronaut to the Red Planet.
“At NASA, we work on many things at once, and we haven’t lost sight of Mars,” The NASA administrator said.
To learn about NASA’s current nuclear efforts, visit: https://www.nasa.gov/ignition/
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.