Research On Electromagnetic Detumbling Method Of Space Debris Based On Two-satellite Formation

With the increasing frequency of global space launch activities,the number of space objects has increased dramatically,resulting in an increasing risk of collisions,which seriously threatens the sustainable development of space resources and human space exploration activities.Active debris removal(ADR)has been internationally recognized as a necessary measure to curb the growth of space objects and maintain the long-term stable development of the space environment.Many ADR concepts involving the capture and removal of targets by service spacecraft can realize the controllable de-orbit of space debris,and avoid harm to other spacecraft and the ground environment.However,space debris typically has a complex rotational motion that increases the risk of destructive collisions.Therefore,it is necessary to eliminate the rotational motion of the debris before capturing it to reduce the risk of collision during capture.High-speed rotating space debris has high energy and great risk of disintegration,which is a potential source of space debris and should be removed as a priority.Aiming at the requirements of onorbit capture of space debris such as defunct satellites and rocket bodies,a new noncontact de-tumbling method using a two-satellite electromagnetic formation is proposed,in which two small electromagnetic satellites,each having a high-temperature superconducting coil,generate control torques to reduce the rotation rate of debris prior to making any physical contact.The two-satellite formation generates a magnetic field around the target.When the target rotates relative to the external magnetic field,eddy currents will be induced in its conductor structures.The interaction between the eddy currents and the external magnetic field generates an electromagnetic torque that hinders the relative motion,reducing the angular velocity of the target.For a variety of electromagnetic detumbling scenarios,the electromagnetic force modeling and analysis of space debris electromagnetic detumbling systems are carried out.The analytical expressions of far-field electromagnetic force/torque of a homogeneous sphere target rotating in the magnetic field of a single coil or double coils are derived.The induced electromagnetic force / torque of homogeneous cube and cylinder are analyzed by numerical method,and an equivalent sphere theory for calculating the electromagnetic force / torque of a non-spherical target is proposed.Aiming at the common non-homogeneous aluminum honeycomb sandwich panel structure in the spacecraft structure,a homogeneous equivalent conductivity model is deduced,and the applicability of the equivalent conductivity in the calculation of induced electromagnetic force is verified by numerical simulation,which provides a theoretical basis for the homogeneous equivalent of aluminum honeycomb sandwich panel structure.For distributed multicoil detumbling scenarios,the coil configurations that achieve the maximum detumbling electromagnetic torque are obtained by numerical optimization,and the electromagnetic force/torque modeling and analysis are carried out.Dynamics and analysis of the electromagnetic detumbling system of the electromagnetic detumbling system using a two-satellite formation are carried out.The geomagnetic field and the onboard coil are characterized as magnetic dipoles,and the disturbance force/torque of the Earth’s magnetic field on the tumbling target and serving satellites are modeled and analyzed.Considering the influence of the relative motion of the serving satellites to the external magnetic field,the expressions of the electromagnetic force/torque of the two-satellite electromagnetic detumbling system in the orbital coordinate system are derived.Based on the classical Newton-Eulerian method,the translational dynamics model of the serving satellite relative to the target,and the attitude dynamics model of the target and serving satellite are established.A research on the two-satellite electromagnetic detumbling strategy is carried out.The motion state of the service satellites in each cycle of the two-satellite electromagnetic detumbling is divided into four stages: acceleration approaching the target,decelerating approaching the target,accelerating away from the target,and decelerating away from the target.The magnetic moments of the onboard coils undergo the process of in-direction,out-direction and in-direction again.Considering the geomagnetic accumulation effect,a detumbling strategy is proposed to suppress the accumulated angular momentum of the geomagnetic moment by periodically flipping the direction of the magnetic dipoles of the coils.Numerical simulations are carried out for the targets in LEO and GEO to analyze the influence of the initial positions of the onboard coils,the commutation positions of the magnetic moments of the coils,the angular velocity and the orbital height of the target on the detumbling effect and the detumbling trajectory,and to verify the detumbling ability of two-satellite electromagnetic detumbling to the multi-axis rotational motion of the target.The cumulative effect of geomagnetic moment is analyzed by numerical simulation,and it is proved that the proposed detumbling strategy can restrain the increase of the cumulative angular momentum of the geomagnetic moment and reduce the risk of saturation of the angular momentum of attitude control mechanism.To verify the effectiveness of the electromagnetic force/torque model and the twosatellite electromagnetic detumbling method proposed in this paper,experimental environments are set up and experimental researches are carried out.An experimental platform is built to verify the established electromagnetic force and torque models and some important conclusions.A rotor-type 3-DOF satellite simulator and a rotating target simulator based on air-floating are developed,and a two-satellite electromagnetic detumbling ground experimental platform based on a marble air-floating platform is built.Based on the ground experimental platform built,the experimental study on the electromagnetic detumbling using a two-satellate formation is carried out,and the feasibility of the proposed electromagnetic tumbling method is verified.