Space debris Removal isn’t just messy—it’s a threat. As more satellites go up, more defunct hardware, fragments, and debris accumulate in low Earth orbit (LEO). When stuff is moving at orbital speeds, even a tiny bolt can damage a satellite or worse. So when scientists propose a new way to remove debris without physically grabbing it, it’s big news. A recent development in plasma thruster technology promises to push large objects out of orbit safely, efficiently, and without risky contact.
Why This Innovation Matters
The growing risk of orbital collisions and cascading debris (known as Kessler syndrome) makes effective, reliable debris removal crucial.
There are thousands of pieces of debris in LEO, many large enough to be tracked and potentially collide with satellites and the International Space Station. Sources say large debris (meter‐scale, ton‐scale) is especially dangerous. If a large satellite or rocket body breaks apart (due to collision or failure), it can create many fragments, which themselves can cause further collisions. Over time, debris can multiply, making parts of low Earth orbit hazardous or unusable. Removing large debris before it fragments is one of the best defenses.
The new bidirectional plasma thruster is designed to tackle exactly that: applying a decelerating force to big debris, without needing to attach or grapple with them, thereby reducing risk and possibly preventing Kessler-like runaway scenarios.
What’s New: The Bidirectional Plasma Thruster with Magnetic Cusp
The key technical leap is combining bidirectional plasma ejection with a magnetic “cusp” field, enabling higher deceleration force toward debris while maintaining zero net reaction force on the removal satellite itself.
A recent paper (published August 20, 2025 in Scientific Reports) demonstrates a “cusp‐type bi‐directional radiofrequency (rf) plasma thruster” that can eject plasma in both directions. One plasma beam is directed at the debris (slowing it), while another is ejected in the opposite direction to balance the system so the spacecraft doesn’t drift. The cusp magnetic field configuration improves performance, allowing more plasma to avoid being lost to walls, increasing thrust. With this setup, the lab experiments reached about 25 milli‐Newtons (mN) of deceleration force. In simpler bidirectional setups without the cusp, plasma tends to interact with the structure (walls, etc.), dissipating energy and reducing how much of the plasma momentum is delivered to debris. The cusp field acts like a guiding shape for magnetic field lines that helps keep plasma away from walls, so more of it pushes debris rather than being wasted. The opposite exhaust balances the recoil, so the removal satellite stays roughly in position.
Achieving ~25 mN gets the system close to the needed performance for deorbiting large debris in reasonable times. This shows the concept isn’t just theoretical—it’s becoming practical.
How It Works: The Science Behind It
The thruster uses radiofrequency plasma, magnetic nozzles, and a specially shaped magnetic cusp field to generate controllable bi‐directional plasma ejection. The setup involves an RF antenna to ionize a propellant gas (argon, in this case), producing plasma inside a source tube. Magnetic coils (solenoids) near the exits create a magnetic field shaped so that two “open‐source exits” eject plasma on opposite sides. Experiments vary currents and gas flow to tune how much plasma goes each way. The cusp field concentrates and shapes the magnetic field to reduce plasma losses to walls, improving efficiency. Ionization gives charged particles (ions+electrons). Magnetic nozzles guide these charged particles, letting them expand and accelerate, converting thermal/electromagnetic energy into directed momentum. The dual exits allow one stream to aim at debris (slowing it) and the other to counterbalance thrust. The cusp region is where magnetic field lines converge or shape well, so that plasma stays in optimal paths and doesn’t prematurely hit thruster structural walls (which would waste energy and heat the structure). Using argon helps because it’s abundant and cheaper than more typical propellants like xenon.
This combination of technologies—rf ionization, magnetic nozzle + cusp, bi‐directional exhaust, argon propellant—makes this proposed system special. It bridges gaps between earlier concepts and what might be feasible in orbit.
How Strong Does the Force Need to Be & How Close Are We?
To deorbit large debris in a practical timeframe (100 days), you need around 30 mN of sustained decelerating force. The recent experiments reach ~25 mN, putting the system close but not quite at that benchmark yet.
The new paper states that ~30 mN is the target for such debris removal missions. The August 2025 lab results using the cusp configuration achieved ~25 mN, about three times higher than prior straight‐field experiments. The difference between 25 mN and 30 mN may seem small, but in practice it can mean several extra days or weeks of operation, or more power/fuel usage. Still, getting into the mid‐20s is close enough to show strong viability; further optimization could push it over the threshold.
This level of performance suggests that in the near future, such thrusters could be part of real debris removal missions, especially if power sources and satellite integration challenges are addressed.
What Makes This So Special Compared to Other Ideas
This approach combines a number of strengths—non‐contact operation, balanced forces (so the removal spacecraft stays stable), use of cheaper propellant, and increased efficiency via magnetic shaping—that many other methods don’t offer all together.
Other proposed methods include nets, tractors, tethers, robotic arms, laser ablation, or ion beam shepherds. Many involve mechanical contact (which is risky with tumbling debris), or high cost, or lower efficiency. The bidirectional plasma beam method being developed avoids contact, and this recent work finally achieves near‐practical thrust levels. Also, the use of argon reduces propellant cost.
Methods like nets or robotic arms have to physically reach and grab the debris—hard if it’s spinning, tumbling, or otherwise moving unpredictably. Laser ablation requires high precision and strong lasers, and may have side‐effects (reflective surfaces, partial ablation). Ion beam shepherding requires complex setups and also has issues with recoil / station‐keeping. This new thruster setup packages many helpful features: you can push debris without touching it; control your own spacecraft’s position; use more affordable materials; shape the magnetic field to improve efficiency.
That’s why many are calling this development a milestone. It doesn’t solve every problem (not yet), but it brings several advantages in one system.
Remaining Challenges & What Must Be Solved
While promising, there are still several engineering, operational, and scaling challenges before this technology can clean up large debris in orbit.
Key issues include high power requirements (kilowatt‐levels), scaling from lab vacuum chamber distances to real orbital distances (meters to tens of meters), handling debris motion and relative motion (target might be tumbling or drifting), durability of components under plasma exposure, heat and energy losses, and ensuring safety. The reports note that the lab was a vacuum chamber setup and closer distances than would be expected in orbit. In the lab, you can place the target “debris” plate just tens of centimeters away. In orbit, the debris will be moving, possibly tumbling, and you’ll need to maintain some safe distance. Plasma beams diverge; magnetic shaping helps but cannot eliminate divergence. Also, generating and managing enough power, cooling, handling wear and erosion over long periods — these are classic challenges in propulsion engineering. Finally, mission design, satellite control, and regulatory issues (which object to target, how to fund, coordinate internationally) need addressing.
Addressing these challenges will be necessary before the system becomes deployed, but the progress so far suggests that these problems aren’t impossible—they are engineering tasks rather than fundamental blockers.
What This Means for Our Space Future
If perfected and deployed, this thruster could become a key tool in making space safer, extending the usable lifetime of Earth orbits, protecting satellites, and preventing cascading debris disasters. By enabling non‐contact removal of large debris, the system directly attacks high‐risk fragments before they break up. Preventing Kessler syndrome (where debris collisions generate more debris endlessly) preserves possible orbits for future missions. Additionally, cheaper propellant (argon) and more efficient designs could make removal missions more economical. Satellite operators spend time and fuel maneuvering to avoid debris; collisions can damage expensive hardware or interrupt services. Clean orbits reduce those risks. Beyond that, as more countries and companies launch satellites (e.g. constellations), orbital space is getting crowded. If debris continues to accumulate unchecked, some orbits might become too risky to use. A reliable debris removal capability gives humanity more breathing space.
So this isn’t a fringe academic idea. It’s central to the question: Can we keep using space safely and sustainably? This thruster development shows that we’re moving from “we need solutions” to “solutions are becoming usable.”
What Can Be Learned & What To Look Out For
Beyond the science, there are lessons in design, collaboration, and what to monitor next.
The research builds on past experiments (2018 and onward), refining designs (adding cusp fields), optimizing efficiency, using more abundant propellants. Also, lab experiments are gradually increasing thrust and power. Good engineering often means iteration: test, measure, learn, improve. Here we see that pattern. Also, choices like using argon instead of xenon show that cost and supply are part of innovation, not just pure physics. Another lesson is that non-contact ideas, though harder in some ways, may be safer and more scalable in the long run.
As this line of work continues, we should watch for: successful small‐scale space tests (in orbit), improvements in thrust vs power, handling of real debris motion, and how such systems fit into regulatory/international cooperation frameworks.
Conclusion
We’re at a moment where cleaning up space might shift from theory to practice. The cusp‐type bidirectional plasma thruster is not perfect yet, but it ticks many of the right boxes. It brings non-contact, stable, relatively efficient, and relatively affordable means of pushing space junk out of orbit. The recent experimental result of ~25 mN deceleration force is tantalizingly close to what is needed for large debris. If the engineering challenges can be solved—power supply, thermal and erosion issues, maintaining distance, cost—it could become a foundational technology in preserving low Earth orbit.
Space, after all, is not just above us—it’s essential to modern life. From GPS and weather forecasting to communications and Earth observation. The cleaner we keep our orbits, the safer and more productive our space activities will be. This latest development doesn’t just point toward possibility—it shows progress. And that deserves excitement. Explore the Cosmos with Us — Join NSN Today
