SITAEL's high-power Hall thrusters and air-breathing electric propulsion

Abstract

Electric Propulsion (EP) technologies proved capable of significant performance improvements over traditional chemical systems and, consequently, made great technological and commercial progress over the past decades, with applications to geostationary satellites, exploration missions, and low Earth orbit satellite constellations [1]. Air-breathing electric propulsion may represent a disruptive approach to open new mission scenarios. From very-low Earth orbits to the deep space, the use of an electric power source to accelerate a propellant and generate thrust poses several scientific and technological challenges [2]. On-ground testing is one of the most complex tasks in developing plasma thrusters, requiring a representative environment and ad-hoc diagnostics. Recreating a representative environment is even more complex in the case of air-breathing electric propulsion, in which we need to generate a flow of atmospheric particles moving toward the spacecraft at almost 8 km/s. Modelling and simulations are then fundamental to investigate processes, as the particle collection or the plasma acceleration, that can be significantly affected by the limits of ground testing. Understanding the physics behind the operation of plasma thrusters can help improving their performance and reducing the complexities of space qualification. Open areas of research concern the characterization of anomalous transport and of discharge oscillations [3], which hinder the implementation of self-consistent and predictive models. At the same time, specific experimental activities and diagnostics shall be designed to validate the models and the numerical codes. In this talk, I will present the activities performed at SITAEL on plasma thrusters and air-breathing EP, focusing on the development and testing challenges, as well as on modelling and simulations.