Dynamic modeling and simulation of electrodynamic tether system in stationkeeping phase

Dynamics is one of the fundamentally important aspects of all space tether research. This paper derives the dynamic equations of electrodynamic tether system (EDT) in stationkeeping phase using Newton's laws. This paper further analyzes the tether system motion rules under electrodynamic drag, gravity induced force, and tether tension. Numerical simulation of electrodynamic tether system in station-keeping phase is calculated using an approach that combines the central difference method, fourth-order Runge-Kutta method, and predictor-corrector method, among others. The simulation results show that the motion of electrodynamic tether in stationkeeping phase not only contains librations caused by the motion of endmass, but also contains vertical and longitudinal vibrations of tether. If the motion of endmass is ignored, it is much similar to the vibration of cable with two immovable pinned-supports, in which the mid-span has the largest amplitude of vibration. Based on this, the main satellite and the endmass at both ends of tether can be treated as immovable pinned-supports when the tether vibration and tension of electrodynamic tether system in impermanency are investigated.