Systems-Level Feasibility Analysis of a Microsatellite Rendezvous with Non-Cooperative

The United States is very dependant upon the use of space. Any threat to our ability to use it as desired deserves significant study. One such asymmetric threat is through the use of a microsatellite. The feasibility of using a microsatellite to accomplish an orbital rendezvous with a non-cooperative target is being evaluated. This study focused on identifying and further exploring the technical challenges involved in achieving a non-cooperative rendezvous. A systems engineering analysis and review of past research quickly led to a concentration on the guidance, navigation, and control (GNC) elements of the microsatellite operation. While both the control laws and orbit determination have been previously evaluated as feasible, the integration of the two remained in question. This research first validated past efforts prior to exploring the integration. Impulsive and continuous thrust control methods, and linear and nonlinear estimator filters were all candidate components to a potential system solution. A simple yet robust solution could not be found to meet reasonable rendezvous criteria, using essentially off-the-shelf technology and algorithms. Results reveal a simple linear filter is a misapplication and will not at all work. A nonlinear filter coupled with either a continuous or impulsive thrust controller was found to get somewhat close, but never close enough to attach to the target satellite. Successful GNC subsystem integration could only be achieved for a very simple case ignoring orbit perturbations such as the earth's oblateness. A top-level system architecture for a non-cooperative rendezvous microsatellite has been developed. The technical complexity, however, requires more complex algorithms to solve the rendezvous problem.