Recent developments in satellite technology can be characterized by two notable trends: miniaturization and clustering. The emergence of microsatellite constellations is making a significant impact on both commercial and national defense sectors. The satellite internet market has experienced rapid growth, surpassing $9 billion, and the application of real-time ground observation has proven crucial in recent armed conflicts. As efforts intensify to operate satellites in very-low-Earth-orbit (VLEO) below 450km, lower altitudes offer advantages such as improved satellite communication latency and optical resolution. While very low-Earth orbit (VLEO) offers numerous technical advantages, it is accompanied by a significant obstacle in the form of aerodynamic drag force generated by the sparsely populated upper atmosphere. Employing space propulsion systems can be a paramount solution for drag compensation. However, the requirement for large amounts of onboard propellant presents another challenge, related to the launch cost and structural capability.

The concept of atmosphere-breathing electric propulsion (ABEP) system emerged in the early 2000s as an innovative solution to counter atmospheric drag force without relying on onboard propellant. ABEP is designed to intake the upper atmosphere as a propellant, which is then ionized and accelerated via an electromagnetic field to generate thrust. Despite being in the developmental phase, ABEP has garnered significant attention and undergone active research in recent years. The Non-equilibrium Gas and Plasma Dynamics Laboratory (KNGPDL) at KAIST, led by Professor Eunji Jun, has conducted a conceptual system analysis on ABEP. This analysis employs a numerical approach to examine three key aspects: the performance characterization of the intake process, estimation of the flight envelope, and evaluation of the environmental interactions resulting from the exhaust plasma plume. The calculations are carried out using the computational resources provided by the National Supercomputing Center, ensuring scalability and accuracy.

The numerical simulation of the intake flow is performed using the direct simulation Monte Carlo (DSMC) method, which accurately captures the stochastic nature of the rarefied gas flow. The freestream conditions are obtained via the NRLMSISE-00 global atmospheric model. A parametric characterization of the intake design-performance correlation is conducted, considering the effects of geometry, surface temperature, aspect ratio, and grid duct configuration. The results of this parametric analysis, along with the proposed comprehensive design (depicted in Figure 1), are presented. Furthermore, the composition of the captured propellant is kinetically analyzed, revealing a 10% decrease in the atomic oxygen fraction and highlighting the significance of non-equilibrium kinetics. These findings provide crucial insights for the design of the ionization process.