Stabilisation of the hyperbolic equilibrium of high area-to-mass spacecraft

In this paper we propose the exploitation of anti-heliotropic orbits, corresponding to the hyperbolic solution of the J2 and solar radiation pressure dynamical system, as gateway orbits between the low-eccentricity orbits where atmospheric drag does not affect the motion and the high eccentricity orbits which enter in drag regime. The eccentricity can be maintained in the neighborhood of the unstable point by means of a controller preserving the Hamiltonian structure of the system. In this way, any initial eccentricity close to the equilibrium conditions will lead to a bound trajectory around the controlled elliptic equilibrium. By selecting the time the controller is turned off, one of the two unstable manifolds leaving the equilibrium point can be followed, leading the orbit to become circular of to increase its eccentricity until natural decay occurs.