Aerodynamic simulation study of a space vehicle with atmosphere-breathing electric propulsion in free molecular gas flow

The presence of atmospheric gas in very low orbits $H = 100$–$200$ km, where a spacecraft with an air-breathing electric propulsion (ABEP) should operate, makes it necessary to perform gas-dynamic calculations for more accurate modeling of the dynamics of its movement in orbit. In accordance with the processes under study, such calculations could be divided into 2 types: the external flow of rarefied gas acting on the spacecraft body and the flow in the internal duct of ABEP. In the first case, the moments and forces acting on the spacecraft during orbital motion were estimated, ways to reduce aerodynamic drag are studied, and options for controlling the spacecraft's movement by deflecting control surfaces are considered. In the second case, the gas flow inside the inlet device and the accumulator is studied, the main parameters were calculated, such as 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 functioning of a spacecraft with ABEP in low orbits, and their results are the output data for a theoretical analysis of the dynamics of the spacecraft's motion in orbit. In this article, we consider the parametrically determined geometry of a spacecraft with ABEP 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 spacecraft, part of which is the passive air intake of the propulsion system. The aerodynamic contribution of particular parts of the spacecraft is estimated. The calculations were performed using the Monte Carlo Direct Numerical Simulation (DSMC) method, the numerical model was verified using analytical relations for simple shapes.