Aerodynamic Simulation Study of a Space Vehicle with Atmosphere-Breathing Electric Propulsion in a Free Molecular Gas Flow

The presence of atmospheric gas in very low orbits H = 100–200 km, where a spacecraft (SC) with an air-breathing electric propulsion engine (ABEPE) should operate, makes it necessary to perform gas-dynamic calculations in order to more accurately mode the dynamics of its motion in orbit. In accordance with the studied processes, such calculations could be divided into two types: the external flow of a rarefied gas acting on the SC body and the flow in the internal duct of an ABEPE. In the first case, the moments and forces acting on the SC during orbital motion are estimated, ways to reduce aerodynamic drag are studied, and variants for controlling the SC’s motion by deflecting the control surfaces are considered. In the second case, the gas flow inside the inlet device and the accumulator is studied, the main parameters are calculated, such as the pressure, velocity, and concentration of particles along the longitudinal internal channel, and their influence on the operation of the engine is analyzed. Both types of calculations make it possible to evaluate the possibility of the functioning of an SC with an ABEPE in low orbits, and their results are the output data for a theoretical analysis of the dynamics of the SC’s motion in orbit. In this article, we consider the parametrically determined geometry of an SC with an ABEPE in the form of a flow duct (consisting of confuser and cylindrical parts with a honeycomb channels at the inlet) with solar panels attached to it. The main result of the study is the assessment of the characteristics of the chosen aerodynamic layout of the SC, part of which is the passive air intake of the propulsion system. The aerodynamic contribution of particular parts of the SC is estimated. The calculations are performed using the Monte Carlo direct numerical simulation (MCDNS) method and the numerical model is verified using analytical relations for simple shapes.