Application of spinning electrodynamic tether system in changing system orbital parameters

Abstract

Spinning electrodynamic tether system is known to be promising in many applications, including space debris removal, transportation missions, changing orbital parameters of spacecrafts and so on. Feasibility of spinning electrodynamic tether system for changing system orbital parameters is analysed in this paper. The main advantage of spinning electrodynamic tether system is the stability of its movement under the action of perturbations. However, when the conductive tether spins in a magnetic field, the Lorentz force constantly changes its direction, which leads to the need to develop special control methods that ensure desired change in system orbital parameters. In this paper, control laws are proposed for changing the semi-major axis and the eccentricity of the orbit, which take the change of tether spatial position into account. To change the semi-major axis, the current is regulated by the cosine law. To change the eccentricity of the orbit, the onboard power system provides a given amount of current when the system is near the apogee and perigee of the orbit. The combination of executing both manoeuvres at the same time is also studied. The numerical results show that the proposed laws enable spinning electrodynamic tether system to change the parameters of the orbit to the desired values.

Dynamic Analysis and Libration Control of Electrodynamic Tether for Reboost Applications

“…is an elongation of tether (which obeys Hooke's Law), while E is the Young modulus. The motion of the EDT system relative to the CM is described by equations (1)(2)(3)(4)(5)(6)(7)(8)(9) in the consideration of the tether deformation. It can be seen that if 0, 0 ei == and 21 mm , the equations (1-3) are consistent with the result of Ref.…”

“…Suppose the orbit parameters are slow variables, and then the true anomaly has a very minimal impact on the motions of the EDT system, which is true in the case of the circular orbit (that is 0 e  ). Then the quasi-equilibrium positions of the EDT system are obtained from the equations ( 1)- (3). Take an equatorial plane (namely i=0) for example, setting 3) and denoting = , r T Q r L = (T is tether tension) when the tether is fully deployed.…”

“…The current flowing with in the tether will interact with the Earth's magnetic field suc h that the orbit and altitude of the system can be altered utili zing the resulted electrodynamic force (ED force) without t he expenditure of propellant. The EDT system can widely b e employed in space exploration and exploitation [2], [3]. T wo key applications of the EDT system are those of reboost and deorbiting [4] - [6].…”

Mathematical modeling and partial feedback linearization control of a constrained and underactuated space tether

“…In recent years, green technologies are raising interest with electrodynamic tethers generating control forces by interacting with the ionosphere (Bechasnov, 2021; Sarego et al, 2021). An electrodynamic tether can be manipulated indefinitely but only for very low Earth orbits and under many other limitations (Lu et al, 2019; Xie et al, 2021; Yao and Sands, 2021).…”