Optimal Scheme of Pyramid Deorbit Sail in the Atmosphere and Solar Environment

For the mitigation of space debris, postmission disposal is deemed an essential measure in low Earth orbit (LEO). One possible way of doing this is to enlarge the effective area by using the membrane sail device, so as to enlarge the atmospheric drag (AD) and solar radiation pressure (SRP), and then accelerate the deorbit process. The effective membrane sail area is mainly affected by spacecraft attitude which exhibits different stable solutions in different altitudes. When descending, the space can be divided into the SRP-dominated region, the mix region, and the AD-dominated region in which the mixed region is where the SRP and AD forces are comparable. Thus, for a deorbit mission in LEO, it is necessary to propose an optimal scheme to achieve a rapid and stable deorbit process. In this article, a precise dynamics model of the pyramid deorbit sail is established with the consideration of multisource disturbances, orbit-attitude coupling, and shielding effects. And then, an optimal deorbit scheme is proposed in the above-mentioned three regions to increase the deorbit efficiency. Specifically, in the AD- and SRP-dominated regions, analytical expressions are derived to evaluate the attitude stabilities and offer optimal configuration design solutions. In the mixed region, an optimal control system is designed with the objects of minimum maneuver as well as maximum deorbit efficiency. By using these configuration design and the attitude control methods, a fast and stable deorbit process can be achieved for LEO satellites.