Multiphysics Finite Element Modeling of Current Generation of Bare Flexible Electrodynamic Tether

Abstract

The paper develops a coupled multiphysics finite element method to analyze satellite deorbit by a bare flexible electrodynamic tether. Unlike the existing approaches, the current method assumes that the tether is flexible and deflectable, and its efficiency of electron collection varies along the tether length depending on tether deflection. The orbital motion limited theory, which dictates the electron collection by a bare tether, is discretized and solved with the same finite element mesh as the tether dynamics to couple the electron collection with the tether flexural deflection. The advantages of the new method are demonstrated by numerical simulations. Compared with a reference method based on straight tether assumption, the coupling effect between the electron collection and tether deflection is significant, leading to the dynamic variation of electrodynamic force acting on the tether. Although the deorbit rates predicted by these two methods are almost the same, the new method predicts a shorter stable deorbit period than the reference method. It demonstrates that the new method is more accurate, and it should be used for detailed engineering design.