Low-Energy Planetary Flyby in the Sun-Planet Restricted Three-Body Problem

Compared to the traditional planetary flyby with a high speed or energy, the low-energy planetary flyby orbit could be temporarily captured by the planet and earn at least one more close encounter chance for the planet exploration. This paper proposes a concept of effective planetary flyby (EPF) to investigate the dynamical mechanism of low-energy or low-speed flyby orbits in the Sun-planet planar circular restricted three-body problem. A simple and efficient decomposition method for the EPF motion is presented to elaborate details of the flyby process, such as the revolution and trend of the flyby orbit, and then six subsets for EPF motion in the phase space are obtained. A qualitative analysis uncovers that the energy variation of the low-energy flyby is strongly related to its orbital trend. This result finds that two kinds of EPF motions cannot only achieve significant energy variation but also orbit the planet-satellite system with at least one full revolution. Finally, the above results are applied to design interplanetary transfers from the Earth orbit to the Saturn orbit through a low-energy Jupiter flyby.