| In recent years, much thought has been given to the use of small satellite clusters with distributed sensors to provide large virtual apertures, which have significant weight and packaging efficiencies. One proposed method to maintain the formation shape is with the use of tethers. This dissertation assesses the utility of tethered satellite formations for the space-based remote sensing mission. The research objectives are to determine the effects of energy dissipation on the foundational rigid body dynamics, find equilibrium conditions, apply controls, and assess the relative utility of tethers for formation control on continuously earth-facing aperture clusters.; Energy dissipation is found to have a long-term destabilizing effect on prolate bodies that start in certain (Likins-Pringle) equilibria, while oblate bodies in the same equilibria suffer only short-term destabilization from energy dissipation before settling into a near-limit cycle. Consequently, oblate ring formations are exclusively chosen for the multi-body system.; It is shown that a continuously earth-facing equilibrium condition for a fixed-length tethered system does not exist since the spin rate required for the proper precession would not be high enough to maintain tether tension. The range of required spin rates for steady-spin motion is numerically defined here, but none of these conditions can meet the continuously earth-facing criteria. Of particular note is the discovery that applying certain rigid body conditions to a free-flying formation creates the desired equilibrium condition.; Control methods applied to the tethered system fail to maintain formation orientation or are cost prohibitive. The overall assessment is that tethers have great value for general formations, however, by themselves tethers cannot conduct formation control for continuously earth-facing aperture clusters. Even with additional controls, the utility of tethers for this mission is limited. |
