Development and application of a sizing framework for refuelling-capable ABEP spacecraft

Orbital congestion and the limited reusability of current spacecraft pose major challenges for the sustainability of space operations. Air-Breathing Electric Propulsion (ABEP) spacecraft are a promising alternative that can unlock new orbit regimes and extend operational lifetimes. The objective of this paper is to present the Atmospheric Refuelling Interactive System Solver (ARISS), an open-source multidisciplinary sizing tool that combines ABEP, active in-orbit refuelling, and system-level spacecraft sizing within one reusable framework. ARISS integrates aerodynamic simulations, physical laws, and heuristic methods to generate and verify preliminary spacecraft configurations throughout the detailed design phase. To demonstrate the ABEP design capabilities of ARISS, Thermodiver is presented as a case study of a VLEO spacecraft capable of in-situ refuelling. The resulting vehicle is a 754 kg spacecraft operating at a 195 km, equipped with a semi-specular parabolic intake with 0.636 collection efficiency and a 5000 W ion thruster producing 0.1005 N of thrust. In its reference mission, Thermodiver de-orbits PROBA-V, refuels over 108.4 days, and returns to its original orbit. This study provides a contribution to the validation and rapid, tool-assisted development of ABEP spacecraft, supporting the advancement of cost-effective sustainable platforms for future in-space activities.