In this study three techniques for effectively optimizing orbit transfers of advanced space systems employing low-thrust propulsion are investigated. The first two methods, known as collocation and parallel shooting, are useful for solving boundary-value-problems that results from applying the calculus-of-variations to optimal control problems. The third technique, which is an application of genetic algorithms, will allow for the optimal selection of discrete parameter values such as thruster on/off cycles. The orbit transfer dynamics will be modeled using variational equations based upon modified equinoctial elements. This model will include third-body, solar radiation pressure and shadowing effects as appropriate. The three techniques will be examined for use in optimizing low-thrust planetary orbit insertion and escape trajectories, low-thrust transfers from a planetary orbit to natural satellite orbit, and low-thrust transfers to libration point orbits.
Potential Commercial Applications:The results of this study will be a feasible concept of an orbit transfer analysis tool useful for optimizing the trajectories of advanced space systems. This concept will form the basis of a computer program that can be used to analyze a variety of new space system concepts.
