Influence of Shape on Intake Characteristics of Martian Atmospheric-breathing Electric Propulsion Thrusters

We have researched the possibility of using Direct Atmospheric-Breathing Electric Propulsion (DABEP) thrusters for satellites in low Mars orbits (LMO). Conventional satellites are limited by their propellant capacity, making it difficult to maintain low orbit flights. In recent years, research on DABEP in low Earth orbits (LEO) has advanced aiming to improve the observation accuracy. A utilization of DABEP in LMO eliminates the limitations of propellant capacity, allowing for lower orbit flights and potentially improving the spatial resolution. In DABEPs, the intake performance has a significantly impact on the thrust performance. The atmospheric composition and orbital velocity differ between the situations of LMO and LEO. Therefore, intake characteristics in LMO are different from LEO. Additionally, previous studies focusing on LEO indicate that the intake shape significantly impacts on intake characteristics. Therefore, we conducted numerical simulations using Direct Simulation Monte Carlo to clarify the influence of the intake shape of a DABEP on the intake characteristics, such as compression ratio and capture efficiency, in LMO. The simulation results suggest that the compression ratio in LMO is smaller than that in LEO because of lower orbital velocities of the DABEP in LMO. It is also shown that there is an optimum taper angle at which the compression ratio peaks. Furthermore, the capture efficiency in LMO is almost identical with that in LEO, and it depends on the taper angle of the intake walls.