AAS 97-667
THE EVOLUTION OF HIGHLY-ECCENTRIC ORBITS
J. D. Fischer , P. J. Cefola , and R. J. Proulx- The Charles Stark Draper Laboratory
Abstract
Highly eccentric orbits pose a unique challenge to orbit determination processes. Effected by a broad spectrum of perturbations, they are difficult to model over long arcs. This work models the evolution of these orbits from the mission or operational phase, through the decay phase, to the final degradation of the orbit using both semianalytical and numerical propagation techniques to create a smooth transition between regimes. This work also identifies the perturbation model improvements in the Draper R&D version of the Goddard Trajectory Determination System (GTDS) necessary to improve accuracy for these orbits, such as J2-squared and higher order atmospheric drag effects. One of the improvements, the inclusion of the more comprehensive MSIS-90 atmospheric model, is demonstrated.