“Detour” trajectories for spacecraft flight between Earth and geostationary orbit using Moon's gravity

The Paper gives some results in analysis of “detour” trajectories for impulsive spaceflights between the geostationary orbit (GSO) and the Earth: flight from low-Earth orbit to the GSO as well as “tangential” and “normal” flights from the GSO to the Earth. The gravity field of the Moon is essentially used for these trajectories. The schemes of the flight include coming to the Moon's sphere of gravity influence and close fly-by of the Moon, i.e. they use the lunar gravity assist. From the energy point of view, this “detour” scheme of the flight can be better considerably than the “direct” one. Analysis of the trajectory sensitivity to some perturbations is performed for these trajectories. The coordinates of the initial position, the components of the initial velocity and the initial time as well as some other parameters are varied. The main analysis is performed for the four-body problem (a spacecraft, the Earth with its oblateness, the Moon and the Sun). It is shown that returning the spacecraft from the GSO without a correction is possible using the “detour” trajectory with “normal” re-entry to the Earth atmosphere.