Characterization of the relative motion of rendezvous between vehicles in proximate, highly elliptic orbits.

摘要

This dissertation deals with the subject of rendezvous between two vehicles in highly elliptic orbits. The specific range of orbital eccentricities addressed is 0.6 to 0.9. This research focuses on what is commonly referred to as final rendezvous, the process by which an active (chaser) vehicle is brought from some position in a neighboring orbit to a prescribed stationary position relative to a passive (target) vehicle. Due to the varying orbital speeds of the two vehicles as they travel in their respective orbits, their motion relative to each other is highly initial condition-dependent and varies significantly from the relative motion seen in common, circular orbits. This research sheds light on this non-intuitive motion, exposing the challenges and promise of such rendezvous techniques.; Motivation for the study of highly elliptic rendezvous is given and a summary of relevant, previous rendezvous research is presented. The paper details the development of relative motion targeting and propagation routines, valid for high eccentricities, which output relative coordinates in a suitable curvilinear coordinate system. Parametric studies that utilize the routines developed are presented as an initial characterization of the solution space. This solution space is constrained for this and all subsequent investigations by the definition of two types of co-apsidial target/chaser vehicle relationships.; The software used in the early studies is subsequently married with a genetic algorithm optimization routine and a large number of runs are made to globally characterize and evaluate candidate final rendezvous scenarios. Results of genetic algorithm runs, with and without operational constraints, are presented and summarized and a fuel-optimal family of solutions is identified. A further parametric study is done within the optimal space to explore the rich diversity of final rendezvous geometries still present after the optimization process. Dispersions in magnitude and angle of the rendezvous initiation burn are applied to 36 separate cases found to have both excellent fuel-efficiency and path characteristics that insure target vehicle safety.; Finally, all foregoing results are summarized and three illustrative mission design cases are presented and solved by applying the findings of this research. Recommendations for follow-on investigations are given.