Design, characterization, control, and optimization of a 'super string' deployable truss structure

Compartment size is often a limiting factor when transporting objects into space leading to multivariable design limits striving for both minimum volume and minimum weight systems and structures. As such, components of systems are often folded or packaged so their stowed volume is significantly reduced. These components are later assembled or deployed once orbit is reached. A novel 'Super String' structural concept comprised of carbon fiber longerons and battens connected by hinges that are first free to rotate and subsequently locked to form a rigid structure is presented. Once deployed this structure has a high stiffness-to-mass ratio, because of its sparse box-type construction. A detailed study of a scale technology demonstrator, including design, manufacture of truss deployment machine, motion control with LabVIEWTM and testing will be presented. Performance of the Su- per String truss compared to currently used deployable truss systems shows that it has potential applications in kilometer-sized solar sails. Optimization of the Super String is achieved through exploration of material enhancements to improve structural efficiency. Improvement of fiber-reinforced composite properties is explored in the form of functionalizing fiber surface with Carbon Nanotubes (CNTs). Processing methods, however, are a current limiting factor and have been shown to degrade fiber surfaces and properties. A Shape Memory Polymer (SMP) is considered as a potential means of improving bending stiffness of the structure.