Deployable Composite Boom

Just like a kid's slap bracelet, the Bi-CTM design includes a secondary stable low-energy state aside from the rigid deployed state. The result is that the Bi-CTM is not under high-spring stress when coiled up which simplifies the stowage process as well as enabling a more controllable extension of the boom. The simplified stowage process enables reduced size, mass and complexity of the storage and deployment mechanism system. Compared to the majority of deployable thin-shell booms, which have at best a semi-open cross section, this true closed-cross-section boom is stronger, while keeping the compact nature of rollable booms, and is able to overcome both bend and twist buckling related limitations. Using omega-shaped cross sections with optionally circular, parabolic or ellipsoidal segments, where each half of these thin-shell composite booms can use equal (symmetric boom) or different (asymmetric boom) cross section geometry and/or composite laminates, offers a great deal of boom customization in terms of stable coiled diameter and structural properties. Bi-CTM boom design optimization provides for maximized area moments of inertia and torsional constant, which related to the boom stiffness and the loading capacity, while remaining a bistable design.