Air-Breathing Plasma Engine Could Keep Satellites Aloft in Thin Air

University of Stuttgart researchers propose an Atmosphere-Breathing Electric Propulsion (ABEP) system that uses ambient air as fuel for a RF helicon plasma thruster to sustain Very Low Earth Orbit satellites without frequent refueling. The team tested three air-intake designs, with a specular intake achieving ~94% particle capture, and an MRI-inspired birdcage antenna delivering power efficiently. In vacuum tests at 50–60W RF power, the thruster showed reliability; models suggest operation between 190–250 km with under 1.6 kW, and potential Mars-atmosphere use. Challenges include atomic oxygen corrosion and atmospheric variability, and the concept is not yet mission-ready.