Attitude Stability Analysis and Configuration Design of Pyramid Drag Sail for Deorbit Missions

Deorbit disposal of constellation satellites at the end of their operational lifetime is considered a necessary task to maintain the safety and sustainability of low Earth orbit (LEO). In LEO region, especially below 800 km, the drag sail device emerges as one of the most promising techniques to accelerate the deorbit process by the advantages of atmospheric drag. In this paper, an attitude-orbit coupled dynamics model is established for satellites equipped with pyramid drag sail devices. The number and length of support booms, the flare angle, and the initial orbital height are not limited, so that the obtained model could describe a number of drag sail systems. Then, by simplifying the attitude dynamics model in the orbital plane and considering circular orbit motions, a key parameter is proposed to evaluate the stability of the drag sail system. With this parameter, the influence of geometries on the attitude stability is analyzed for pyramid drag sails, and further conclusions about the optimal configurations are obtained from the analysis results. Finally, numerical simulations with the attitude-orbit coupled dynamics model are conducted to verify the conclusions drawn from the key parameter, and optimal configurations under three different conditions are obtained as well as simulated with deorbit missions to show the optimality. The results from this work would offer theoretical guidance to the configuration design of drag sail systems in application.