Nano-Satellite Deorbit by Bare Electrodynamic Tether

Abstract

This paper studies the dynamics of nano-satellite deorbit by bare electrodynamic tether (EDT). The IGRF2000 model of Earth’s magnetic field up to 11th order term is considered as well as the detailed gravity and aerodynamic models. The results find that the higher order terms of the Earth’s magnetic field model play a significant role in determining the dynamic characteristics of satellite with EDT, especially in the polar orbit or orbits with high inclination angles where the orbit of satellite will become elliptical due to these high order terms of Earth’s magnetic field. This is beneficial for the deorbit of satellite in the near polar orbits where the electrodynamic force is not as effective as the equatorial orbit, because the denser atmosphere at a lower perigee will provide larger atmosphere drag to dissipate the orbital kinetic energy of the satellite faster. Moreover, the analysis shows the kinetic energy dissipated by the current induced electrodynamic force is always negative, which implies the force is always against the motion of satellite even the induced voltage/current across the EDT revers their polarity in near polar orbits. Compared the decay rate by atmosphere drag only, the orbit decay rate of a satellite with EDT will be increased by several orders of magnitudes in both equatorial and polar orbits. Finally, the results indicate that the effect of Earth’s oblateness is negligible in deorbiting satellites.