Dynamics of Gyroscopic Stabilized Tether Satellite System in LEO

This paper studies the dynamics of a tether satellites system composed of two satellites and controlled by a gyroscopic stabilization. This configuration is particularly convenient for remote sensing applications, guarantying a continuous oscillation in the cross-track direction that could be beneficial for synthetic aperture radar missions. The stabilization is obtained by spinning the system about a vector tracing a circumference on the radial along-track plane during the orbit. The rotational motion of the system causes a centrifugal force on the satellites, that provides the tension in tether needed to keep the formation in shape. The behavior of this tethered system in low Earth orbit is analyzed introducing the dynamic equations of relative motion centered in an orbiting reference frame. The equations model the three-dimensional multibody dynamics of the system in this environment, considering all the most important external perturbations. This architecture is analyzed by extensive numerical simulations, which provided insight into the gyroscopic effects on the systems and the effectiveness of this stabilization. Through these simulations, the effectiveness of the stabilization is demonstrated. Moreover, in the long term, precession and nutation motions can be appreciated, which can be directly attributed to the stabilizing effects of the gravitational gradient. These effects are analyzed as angular velocity and tether length vary, inferring the stabilizing effects of angular velocity and the invariance of system dynamics as length varies.