Abstract
In recent years extremely small satellites have been developed in response to trends in the space industry to achieve more for less cost. Extremely lightweight and efficiently packaged deployable structures are essential for achieving large-scale applications including communication antennas, solar arrays, and in recent years, deorbiting drag-sails. This thesis is motivated for developing novel deployable helical antennas for space-based maritime surveillance. The helical antenna technology provides packaging efficiency and radio frequency characteristics superior to the latest efforts of international research groups. To achieve this, the research presented focuses on developing the proven bistable composite slit tube (BCST) deployable technology. These are open-section tubular structures which can be deployed and rolled up into a compact coil, analogous to a tape measure, but do not require constraint to remain stowed. This behaviour is referred to as bistability and enables lightweight and relatively simple deployable structures for spacecraft applications. New forms of BCST are modelled through the introduction of additional curvatures, manufactured and described in this work with two new subcategorisations established: toroidal and helical. Toroidal BCSTs are doubly curved with both principal curvatures initially non-zero in the deployed stress-free state. Helical BCSTs are doubly curved and twisted out-of-plane. Investigations into the effects of geometrical parameters and laminated composite material properties on the bistable coils of both types are presented. The results provide an understanding of bistable behaviour in new forms of BCST previously neglected in the literature, which is almost exclusively focused on straight forms. As a consequence of this research, new deployable structure technologies are envisaged in the areas of compact terrestrial shelters and small satellite communications.