Plasma Thruster Harnesses Thin Upper‑Atmosphere to Keep Satellites in Ultra‑Low Orbit

A new type of plasma thruster that draws its fuel directly from the sparse gases of the upper atmosphere promises to keep satellites operating in very low Earth orbit without the need for onboard propellant stores.

Operating between roughly 100 and 450 kilometres above the planet, very low Earth orbit (VLEO) offers distinct performance advantages: imaging systems can capture finer detail, and communication or radar payloads require less power to reach the ground. The trade‑off has always been the heightened atmospheric drag that quickly depletes orbital energy, forcing operators to carry extra fuel for periodic re‑boosts.

The breakthrough design sidesteps that penalty by ionising the trace amounts of oxygen and nitrogen that persist at those altitudes. An electric field accelerates the resulting plasma, producing thrust that counteracts drag. Because the engine harvests the ambient gas rather than relying on a finite tank, a satellite can theoretically maintain its altitude for the duration of its mission.

Researchers describing the concept note that the system’s power demand aligns with the modest electrical budgets of small satellites, and that the lack of consumables could lower launch mass and cost. By eliminating the need for separate propellant tanks and associated plumbing, designers can free up volume for additional payload or smaller form‑factors, a benefit especially attractive to large constellations seeking to maximise coverage.

While laboratory tests have demonstrated the engine’s ability to generate measurable thrust in simulated VLEO conditions, the next milestone will be an in‑orbit demonstration. Successful validation could reshape how operators plan missions in the lowest orbital tier, extending satellite lifespans, reducing debris risk, and opening new possibilities for high‑resolution Earth observation and low‑latency communications.