Space Tether Deployment Control for Nanosatellites

This thesis investigates the deployment control of space tethers for nanosatellites. More specifically, the problem space is reduced to the deployment of a tether that is housed and autonomously operated on a nanosatellite, connected to a relatively massive satellite. Novel control schemes for this objective has been derived and analyzed in detail, along with the development of linear and nonlinear observers to reduce the resources required to support the deployment process. Furthermore, pulse width pulse frequency modulation technique is leveraged to simplify the actuator required for this mechanism. Finally, advanced simulations that include a multitude of disturbances in the low Earth space environment is introduced to analyze the performance of deployment controllers. The main contributions of this work are the development of controllers under state constraints, the application of a unique nonlinear observer to the TSS state measurement problem and, the application of advanced simulations to validate the performance of TSS deployment controllers under a variety of disturbances. Experimental validation, model uncertainties as well as attitude dynamics has been omitted from the scope of this thesis and is left for future work