Date of Award
Doctor of Philosophy (PhD)
Department of Aeronautics and Astronautics
Richard G. Cobb, PhD
The US Air Force's ability to protect space assets is enhanced by a proficiency in satellite proximity operations and Space Situational Awareness (SSA). In pursuit of that proficiency, this research develops a key capability of interest to mission planners; the ability of a deputy satellite to "hover" within a defened volume fixed in the vicinity of a chief satellite for an extended period of time. This research finds optimal trajectories, produced with discrete-thrusts, that minimize fuel spent per unit time and stay within the user-defened volume, thus providing a practical hover capability in the vicinity of the chief. The work assumes the Clohessy-Wiltshire closeness assumption between the deputy and chief is valid, however, elliptical chief orbits are allowed. Using the new methodology developed in this work, feasible closed and non-closed relative orbits are found and evaluated based on a fuel criterion and compared to an easily calculated continuous-thrust baseline. It is shown that in certain scenarios the discrete-thrust solution provides the lowest overall fuel cost. These scenarios are generally constrained to a smaller total time-of-flight. A simple check is proposed that enables the mission planner to make the correct strategy choice.
DTIC Accession Number
Irvin, David J. Jr., "Optimal Control Strategies for Constrained Relative Orbits" (2007). Theses and Dissertations. 2903.