GEOMETRY PROPERTIES ANALYSIS ABOUT RESONANT ORBITS IN EARTH-MOON SYSTEM

The initial geometry properties about resonant orbits in the Earth-Moon system are investigated. It is found that some initial geometry properties, such as eccentricity and initial phase, provided by two-body theory cannot result in resonant orbits in circular restricted three-body problem (i.e. CRTBP) due to the gravitational capture of the Moon. When closest point of a resonant orbit is in the Moon's sphere of influence (66200km) or the Kepler energy to the Moon is non positive, possible flyby or weakly capture can happen. The position of the closest points to Moon and the Kepler energy distribution with variations of the eccentricity and initial phase are obtained, and the range of eccentricity and initial phase that cannot result in resonant orbits in CRTBP are also given. Examples of the resonant orbits in 1:2, 1:3 and 1:4 exterior resonances and 2:1 interior resonance are provided to verify the analysis, it's found that the method which judging the closest distance between spacecraft and Moon is more accurate.