Trajectories for spacecraft return from geostationary orbit to the Earth using Moon's gravity

Main results of investigations are given for a problem of the spacecraft (SC) return from geostationary orbit (GSO) to the Earth. In addition to “direct” return trajectories with initial decreasing velocity of SC, there are studied “detour” ones with initial increasing velocity, flight from GSO to the Moon for a lunar gravity assist and following flight to the Earth. Main characteristics of trajectories as well as comparison of both return schemes are given. From the energy point of view the “detour” scheme is shown to be better considerably than the “direct” one. The Paper is prepared according to the author’s Presentation at the XXX academic readings for Cosmonautics, January 2006, Moscow.