Scientists Built a Plasma Thruster That Could Vaporize Floating Orbital Junkyard

[Buster's Uncle]

Scientists Built a Plasma Thruster That Could Vaporize Our Floating Junkyard
Darren Orf
Popular Mechanics
Mon, September 22, 2025 at 1:30 PM EDT·3 min read



Scientists Built a Way to Clean Our Space Junkyard VICTOR HABBICK VISIONS/SCIENCE PHOTO LIBRARY - Getty Images


Here’s what you’ll learn when you read this story:

*Thousands of pieces of space junk are littering low-Earth orbit (LEO), potentially imperiling the future of human spaceflight.

*A new study highlights a novel idea to clean up this orbital mess using bidirectional plasma thrusters improved by technologies from fusion reactors.

*This innovative design is now approaching power levels capable of decelerating a one-tonne satellite in just 100 days.


It’s strange to think of space as “littered.” After all, the universe is so vast that it’s nearly impossible for the human mind to fully grasp its immensity. However, detritus is piling up in Earth’s orbital neighborhood, and if one of many hypothesized worst-case scenarios plays out (a.k.a. Kessler syndrome), this maze of space debris could effectively cut off our access to the Solar System entirely.

Scientists have dreamed up two ways of tackling this conundrum—contact and non-contact. Relatively self-explanatory, these two camps each contain various methods intended to slow down space junk so it can safely de-orbit, whether by physically latching onto the debris or manipulating it without direct contact (usually via lasers or ion beams).

Because many of these pieces of debris are tumbling uncontrollably, the non-contact method has gained some traction, and now a new study—published in the journal Scientific Reports from scientists at Tohoku University in Japan—may have stumbled upon the best method yet.

“Most current space debris removal methods are direct-contact approaches and carry the risk of becoming entangled in the uncontrolled motion of debris,” Kazunori Takahashi, the author of the study, said in a press statement. “More recent work has focused on using a plasma thruster to decelerate the debris, forcing it out of orbit.”

Takahashi’s idea dates back to another study from 2018 (also published in Scientific Reports) where he first describes his “bi-directional thruster”—essentially a design with two plasma beams that counteract each other and overcome Newton’s whole Third Law of Motion thing. Although the method worked for smaller pieces of space debris, the plasma thruster didn’t have enough oomph to deorbit larger satellites. To address this problem, Takahashi took some inspiration from fusion reactors, specifically the “cusp magnetic field.”

These special fields are used to ensure that plasma doesn’t interact with the walls of the reactors and is instead the point where opposing magnetic fields meet. This meeting, according to IEEE Spectrum, briefly creates a change of force direction. Hopefully for Takahashi, the applications of a cusp-type magnetic field could increase the power of his plasma engine by essentially containing both the plasma and the direction of the thrust.

When tested in vacuum tubes used to simulate the zero-gravity conditions of LEO, Takahashi discovered that the spacecraft’s deceleration force increased, and when stressed under high-power levels, it delivered up to three times more deceleration force than its 2018 version. At this high level (at about 5 kilowatts), the bidirectional plasma thruster created 25 millinewton (mN) push force, which is only 5 mN short of the threshold for decelerating a one-tonne piece of debris in 100 days.

“This achievement represents a significant technological advancement toward developing a propulsion system capable of efficiently and safely removing space debris,” Takahashi said in a press statement.

This doesn’t quite mean this “cusp-type bi-directional radiofrequency plasma thruster” is ready to be packed up and shipped out to LEO. Understanding the complexities of maintaining a safe distance from dangerous space debris while decelerating over a period of months is more than just tricky. Of course, there’s also a reason why bidirectional rockets aren’t particularly popular—twice the rocket, twice the fuel. Luckily, plasma thrusters are much more fuel efficient than chemical rockets, but the heavier the spacecraft, the pricier the launch.

And there’s a lot of clean up to do.

https://news.yahoo.com/news/tech/science/articles/scientists-built-plasma-thruster-could-173000580.html