INVARIANT RELATIVE SATELLITE MOTION

Formation flying is a key technology enabling a number of missions which a single satellite cannot accomplish: from remote sensing to astronomy and fundamental physics. The design of relative navigation and control systems of the spacecraft is certainly one of the most challenging topic. In order to ease the tasks of these subsystems, a proper reference trajectory must be conceived, and a relative motion, which shows no drift even in presence of a large disturbance as the J2 effect, could be a very attractive solution. This paper describes the research activities for finding invariant relative orbits under J2 effect. Numerical tools as genetic algorithms enabled the discovery of two special inclinations which represent the necessary conditions for periodicity of the motion. These results generated interest, and analytical explanations for the numerical evidence have been proposed: on-going studies face this problem from different points of view, and basic results are reported