Libration suppression of moon-based partial space elevator in cargo transportation

Abstract

This paper studies the libration suppression of a moon-based partial space elevator in the Earth-Moon three-body system. The elevator is connected to the Moon surface by a tether and a space station is connected to the free end of tether as the end body. One or multiple climber(s) can move along the tether to transfer cargos between the Moon and the end body. A high-fidelity dynamic model is derived to describe the motion of the climber(s), the end body and the flexible tether by the combination of rigid body dynamics and nodal position finite element method. The validity of the proposed model and the effect of element discretization along the tether on the dynamic behaviour of the elevator are investigated through numerical simulations. To ensure the stability and satisfy the mission constraints in the cargo transfer period, an optimal control based on the high-fidelity model is employed to regulate the control input with limited magnitude. Case studies show that by adjusting the thrusts on the end body reasonably, the libration of the Moon-based partial space elevator can be suppressed with limited control input effectively.