Propulsion system sizing for servicing spacecrafts

The initial sizing of the propulsion system takes an important role in the preliminary design stage for space missions. The aim of this paper is to present an initial sizing method to evaluate the amount of propellant required for the on-orbit servicing spacecraft that can upgrade on-orbit satellites. Specially, one servicing spacecraft (SSc) is considered to be initially in the same direction as the target satellite in an adjacent orbit. The SSc then rendezvous with the target satellite and services it. An initial sizing method is presented with an approximate guidance method that the solution process composes analytic solutions for two thrust arcs and one Keplerian free-flight phase, and a homogeneous central field is utilized to approximate the Newtonian field in the boost-phase. It is shown that the approximate guidance method is simple and the precision of the solutions is admitted for the initial sizing.