New Satellite Engine Concept Uses Atmospheric Gases for Indefinite VLEO Orbit

Atmosphere-Breathing Electric Propulsion Concept

Francesco Romano's PhD research at the University of Stuttgart explores a satellite engine concept that utilizes atmospheric molecules as fuel for a plasma engine. This technology, known as atmosphere-breathing electric propulsion (ABEP), collects thin air in front of a spacecraft, converts it into plasma, and expels it to generate thrust. The concept aims to allow satellites to operate indefinitely in Very Low Earth Orbit (VLEO) without carrying traditional propellant.

VLEO Advantages and Challenges

Very Low Earth Orbit (VLEO), ranging from 100 to 450 km, offers benefits such as sharper remote sensing images, reduced power needs for communications, and natural removal of inactive satellites by atmospheric drag. However, atmospheric drag also continuously slows spacecraft, necessitating constant thrust to maintain orbit. Conventional propulsion systems rely on costly onboard fuel like xenon.

Engineering Hurdles: Atomic Oxygen

Developing a practical ABEP system involves significant engineering challenges. One primary issue is atomic oxygen (AO), which is prevalent in the upper atmosphere. AO is highly oxidative and corrodes metal electrodes, acceleration grids, and cathodes used in standard ion engines. This corrosion can compromise critical components, including the electron gun that neutralizes the spacecraft, which is essential for effective ion propulsion.

Engineering Hurdles: Atmospheric Variability

Another challenge for VLEO engine design is the variability of the atmosphere itself. Atmospheric conditions change based on the day/night cycle, latitude, and solar activity. Ensuring consistent engine performance across these fluctuating conditions is a complex design requirement.