A Low Atmospheric Density Multiple Aero-Assisted Orbit Transfers Method for Orbit Vehicle

Fuel consumption and arrival orbit inclination are the most significant challenges for onorbit vehicles engaged in low Earth orbit (LEO) activities, and aero-assisted orbit transfer (AOT) has been proposed as a fuel-saving orbit transfer strategy. However, the low initial velocity in LEO poses challenges for the vehicles’ AOT process, as the transfer must satisfy thermal constraints and achieve the required orbit inclination changes. In this paper, a twolevel optimization strategy for AOT is proposed for vehicles transferring from a higher to a lower orbit in LEO, aiming to increase the orbit inclination change while maintaining fuel efficiency. At the basic level, the vehicle’s glide trajectory in the atmosphere is optimized to address the single-AOT target and path constraints. In this step, a suboptimal reference guidance command is derived for trajectory tracking. At the higher level, the limitation of insufficient orbit inclination change achieved by a single LEO AOT is overcome by implementing multiple AOTs based on the “pseudo-target orbit” strategy. Finally, simulation results demonstrate that the proposed strategy achieves greater fuel savings than both the Hohmann orbit transfer and single-AOT under the same orbit inclination change requirements.