Francesco Romano at the University of Stuttgart has developed a satellite engine concept that uses atmospheric gases as fuel, potentially allowing spacecraft to remain in orbit indefinitely. The technology, known as atmosphere-breathing electric propulsion (ABEP), collects extremely thin air in front of a spacecraft and converts it into plasma to generate thrust. This approach could eliminate the need for conventional propellant, addressing the major challenge of atmospheric drag in Very Low Earth Orbit (VLEO).

The system faces significant engineering hurdles, particularly atomic oxygen (AO), which corrodes metal electrodes and cathodes. Romano designed a contactless, neutralizer-less radio-frequency (RF) helicon plasma thruster to mitigate these issues. He tested three intake designs: an enhanced funnel, a diffuse hexagonal intake, and a specular parabolic mirror. The specular intake proved most effective, collecting 94.3% of particles in wind tunnel tests. While laboratory results are promising, performance in an actual mission remains unproven.