Station-keeping of a solar weather detector by a tethered-sailcraft within elliptic Sun-Earth restricted three-body system

To detect and forecast solar weather in advance is of great importance for humankind to protect power infrastructure on ground and communication satellites in orbit from damaging. In this regard, a large space platform consisting of a solar weather detector, long space tether and a sailcraft with actively adjustable lightness number is constructed. Within the elliptic Sun-Earth restricted three-body system (ESERTBS), merely the motion of the platform along the Sun-Earth line is focused on, full nonlinear dimensional and dimensionless dynamics of the system is established with a massless, taut and rigid/flexible tether. A sliding mode controller is developed to make the closed-loop dynamics asymptotically stable and the prescribed constant dimensional distance between the Sun and detector is maintained thereby. The time histories of some critical variables of the closed-loop system are presented to verify the performance of the developed controller, to check the lightness number of the sailcraft required, to show the internal tension/strain within the tether etc. Moreover, the steady-state responses of the closed-loop dynamic system are also presented to give more information. The lightness number of a single sailcraft used for performing the mission is compared to the lightness number of the sailcraft of the proposed platform. Some discussions and suggestions for selecting the tether’s length and elasticity are presented from the aspect of the lightness number required, the internal tension and strain based on numerical simulations.