Development of a diagnostics setup used for characterizing a VLEO particle flow generator

Earth’s residual atmosphere in the very low Earth orbit (VLEO) can be used as a fuel source for air-breathing electric propulsion (ABEP) systems, supplying satellites with a virtually unlimited amount of propellant so that mission lifetime becomes independent from fuel storage. Operating future satellites at such altitudes offers advantages, including low-latency communication, high-resolution Earth observation, the potential to reduce launch costs, and a rapidly self-cleaning orbit, thereby reducing the risk of long-term space debris. To characterize performance and reduce development time and costs for ABEP systems, the capability to conduct terrestrial tests of complete ABEP systems in vacuum facilities is crucial. Since 2021, a VLEO particle source has been under development at Institute of Aerospace Engineering (ILR) at TU Dresden for various applications, including material testing and ABEP system testing. This paper presents a concept for a suite of four combined diagnostics to determine the flux density and average velocity of the particle beam, which shall primarily consist of neutral atomic oxygen and molecular nitrogen, to precisely replicate the VLEO residual atmosphere. The selected diagnostics will be described, along with an explanation of how they work together to detect as many beam parameters as possible. The basic principles of the ABEP test facility are discussed, with binary conditions focusing on altitudes between 180 km to 250 km.