Novel Partial Space Elevator via an Electrodynamic Tether for Cargo Transportation

A novel partial space elevator for cargo transportation is proposed with a conceptual design of an electrodynamic tether to provide clean and propellant-free driving force for climbing motions and to control the coupled attitude motions of tethers. The nonlinear dynamics and control of the upward and downward cargo transportation problems are addressed for the novel elevator. Based on an assumption of a 2-piece dumbbell model, a 3-dimensional dynamic model of the system is established by involving the coupling motions between the electrodynamic forces, tether tension, and tether attitude motions. Accounting for the complicated dynamics and system constraints, a nonlinear model predictive controller is proposed to achieve the stable cargo transportations by adjusting the tether current and tension. Finally, 2 numerical simulations are given to validate the novel design and to verify the effectiveness of the controller. The simulation results manifest that the appealing clean technology is feasible to long space cargo transportations without the requirements of chemical propellant and additional thrusters.