Recent research in satellite propulsion is exploring an innovative concept in modern space engineering: utilizing the residual atmosphere in very low Earth orbit (VLEO) as propellant. This approach, known as air-breathing electric propulsion (ABEP), enables satellites to collect sparse atmospheric particles, ionize them, and accelerate them to generate thrust, reducing reliance on stored propellants like xenon. A significant milestone was achieved on 26 March 2026, when TransMIT’s IQM division announced the successful completion of a Thruster Design Review with ESA for a cathodeless electric propulsion thruster designed for ABEP systems.
Significance of VLEO Satellite Operations
VLEO satellites operate at altitudes much closer to Earth than conventional spacecraft. According to ESA, VLEO ranges from approximately 100 to 450 km, with typical operations between 250 and 350 km. These lower orbits offer advantages such as higher-resolution imaging, reduced communication resource requirements, smaller payloads, and a lower collision risk with long-lived debris due to faster re-entry. However, the residual atmosphere at these altitudes creates continuous drag, which shortens spacecraft lifespans unless actively countered.
The Role of Air-Breathing Electric Propulsion
ABEP addresses this challenge by using the atmospheric particles causing drag as a propellant source. Instead of carrying all propellant onboard, ABEP-equipped satellites collect and utilize these particles. ESA demonstrated the feasibility of this concept in March 2018, achieving the first firing of an air-breathing electric thruster. This test showed that atmospheric molecules could be collected, compressed, ionized, and used to produce thrust in a simulated environment representative of 200 km altitude. ESA’s GOCE mission also highlighted the potential of electric propulsion, operating as low as 250 km for over four years, though its lifetime was limited by the 40 kg of xenon it carried.
Technical Advancements in ABEP Systems
The 2026 development by TransMIT introduces a notable technical improvement. The company’s design employs a radio-frequency ion engine with cathodeless functionality, eliminating the need for a cathode sub-assembly, a challenging component in ABEP systems. This project aims to create a configuration suitable for small-satellite platforms while maintaining drag-compensation capabilities. This indicates a shift from theoretical exploration to refining ABEP architecture into a lighter, more robust, and operationally viable system for future spacecraft.
Industry Implications and Challenges
ABEP technology holds significant potential for the satellite industry. It could enable spacecraft to operate below 250 km for extended periods by reducing or eliminating the reliance on stored propellant, thereby addressing a key lifetime constraint. This advancement could support constellations with enhanced Earth observation capabilities, lower latency communication links, and simpler end-of-life disposal due to VLEO’s self-cleaning nature. However, substantial engineering challenges remain, including air intake performance, drag compensation, realistic testing, erosion, and sustained system integration. While satellites cannot yet operate indefinitely on atmospheric particles alone, ABEP is progressing from concept validation to credible mission-enabling hardware.
Future Prospects for ABEP Technology
From a market and technology perspective, the development of ABEP, VLEO satellite technology, and air-breathing electric thrusters is gaining importance as operators seek cost-effective and high-performance orbital architectures. If developers can transition from design reviews and laboratory demonstrations to reliable flight systems, ABEP could become a critical enabling technology for the next generation of VLEO missions. While this future remains under development, the progress achieved so far indicates meaningful advancements in this field.