On the dynamics of a subsatellite system supported by two tethers

The dynamics of a subsatellite system connected to a main orbiter by two extensible but massless tethers is studied. The points of attachment of these two tethers are offset from the centre of mass of the orbiter. Both constant length and retrieval cases are considered. Lagrangian formulation for constrained systems is used to derive the nonlinear equations of motion. These along with the constraint equations are solved numerically. It is noted that the rotational motion in the plane of the attachment points can be damped quite effectively using a simple control scheme. Comparisons are made with the single tether case. A two tether system has superior rotational behaviour, but seems to have disadvantages as far as longitudinal oscillations are concerned.