EFFECTS OF AERODYNAMIC LIFT ON THE STABILITY OF TETHERED SATELLITE SYSTEMS

Dynamics and stability of a two-body tethered system are investigated considering the aerodynamic lift on the subsatellite in addition to th e aerodynamic drag. The free molecular flow model is used to calculate the aerodynamic forces on the subsatellite. Equilibrium configuration s of the system are obtained numerically. Equations of motion are line arized analytically about the equilibrium configuration through a symb olic manipulation language, Maple V, and stability behavior of small o scillations about the equilibrium configuration is analyzed. An extens ive parametric study is done to understand the effect of aerodynamic f orces (lift and drag) on the stability of the uncontrolled system. It is shown that the stability behavior changes significantly if the subs atellite is changed from a body with no lift to a body with lift. Henc e, an unstable system with a spherical subsatellite can be stabilized if appropriate aerodynamic surfaces are added. It is concluded that co nsideration of the aerodynamic lift in addition to the aerodynamic dra g on the subsatellite is indispensable for proper design of a tethered subsatellite system deployed in a low altitude orbit.