Title of Presentation: New Low Energy Motions in the Earth-Moon System, Chaos, and the Weak Stability Boundary

Primary (Corresponding) Author: Edward Belbruno

Organization of Primary Author: Innovative Orbital Design, Inc., and Princeton University

Abstract: New results are presented for this research effort, year one, of this three year program. A main result that has been recently obtained is a detailed understanding of a region about the Moon called a weak stability boundary(WSB) and new significant applications. This region has been known to exist since 1986, and has important applications for its use in obtaining a new type of transfer to the Moon, using ballistic lunar capture(no DeltaV). One of these transfers was demonstrated by this researcher in 1991 with the rescue of the Japanese lunar spacecraft Hiten. Another was used in 2004 for ESA’s SMART-1 spacecraft as well. However, a deep understanding of this region has been elusive. Now, through this research effort, the nature of the WSB has been finally uncovered. It is shown to support only resonance motions about the Earth, in resonance with the Moon, which chaotically transition from one type to another. This is a surprising discovery and an important one. It has been uncovered through the use of special visualizations on so called surfaces of section which have an exquisite geometric structure. The WSB itself has been shown to be an interesting dynamic region existing within a chaotic sea about the Moon in the phase space.  These results have already led to an understanding of a new type of transfer type: ballistic escape from the Earth-Moon system. First observed in 1990, they were not understood. Now, their dynamics are clearly seen within the dynamics due to the WSB. These transfers have potentially many important applications, especially for future Mars missions. New types of low energy orbits are also described about the Moon which enable inclination changes for a factor 12 less DeltaV than traditional orbits, enabling new lunar architectures in support of a lunar base.