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 since the propellant is collected directly from the atmosphere. The effectiveness of this technology depends on crucial aspects such as the collection and compression performance characterization, as well as the drag estimation and compensation. In the first part of this study, the lower Mars and Earth atmospheric characterization is derived based on current models and mission data. This characterization is a reliable dataset for the boundary conditions for the simulations carried out in the second part of this study. The proposed computational framework based on the Direct Simulation Monte Carlo method aims to investigate the collection and compression performances and to estimate the drag. The numerical comparison with a literature case validates the numerical setup presented in this study. The effect of different gas-surface interaction models is investigated by comparing the results yielded by the Maxwellian model (fully specular and partially diffuse reflection) and the Cercignani-Lampis-Lord model. Since the intermolecular 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, the simulation results of the two cases for the low Mars orbit (150 and 140 km) are compared to the Earth case (180 km).