Numerical Framework for the Development of Atmosphere-Breathing Electric Propulsion for Earth and Mars Atmosphere

Abstract Atmosphere-breathing electric propulsion systems provide a competitive advantage for the lower orbit altitudes sincethe propellant is collected directly from the atmosphere. The effectiveness of thistechnology depends on crucial aspects such as the collection and compression performance characterization, as well as thedrag estimation and compensation. In the first part of this study, the lower Mars and Earth atmospheric characterizationis derived based on current models and mission data. This characterization is a reliable dataset for the boundaryconditions for the simulations carried out in the second part of this study. The proposed computational framework basedon the Direct Simulation Monte Carlo method aims to investigate the collection and compression performances and toestimate the drag. The numerical comparison with a literature case validates the numerical setup presented in thisstudy. The effect of different gas-surface interaction models is investigated by comparing the results yielded by theMaxwellian model (fully specular and partially diffuse reflection) and the Cercignani-Lampis-Lord model. Since theintermolecular collisions can become more relevant at the inlet of the ionization stage, both the variable hard and variable soft sphere models are briefly examined, as well as the inclusion of gas-phase reactions. Finally, thesimulation results of the two cases for the low Mars orbit (150 and 140 km) are compared to the Earth case (180 km).