Multi-Purpose Satellites Constellations Propagator Toolkit

Since ancient times explaining the motion of celestial bodies has been a must and a challenge for scientists. Many people in history, from Ptolomaeus to Copernicus, from Brahe to Kepler, from Galileo to Newton up to Lagrange and Einstein, have investigated the motion of planets, giving birth to celestial mechanics.[1][2] Orbital mechanics is based on the same laws applied to artificial satellites and is pervasively employed in space missions to design orbits according to specific requirements and to predict the movement of satellites over long periods. This has a significant importance in satellite constellations design where the presence of many satellites results in a growing complexity in terms of deployment, dynamics, reconfigurability and control, up to the disposal at the end of life. Today the theory on orbit dynamics is developed, but the problem is to predict the movement of many satellites, choosing the suitable propagator, considering all the perturbations, taking into account the station keeping manoeuvres, tracking and observability. In this paper, an overview of a new kind of orbit propagator is presented, together with an analysis of perturbation corrections using both impulsive and low-thrust manoeuvres (electric engine); some application examples will be presented as well. The paper will deal with the following issues: satellites constellation propagator (from 2 to n satellites), orbital perturbations, Sun visibility, Earth coverage, inter satellites links, station keeping (impulsive and continuous firing).