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Deployable composite booms are particularly attractive in space constrained applications. Their high packaging volume efficiency enables relatively large spacecraft systems required for power generation, communications, or propulsion to be housed within small volumes. COROTUB is a monolithic closed-section tubular thin-shelled structure thats been shown to scale efficiently up to 50m yet maintain its strength. COROTUBs two corrugated thin shells form a closed section, which yields high bending and torsional stiffness, allowing for high dimensional stability. Computational analysis and early tests show that the corrugation provides increased strength against buckling, enabling longer booms and targeting more demanding structural applications than non-corrugated designs. The corrugation geometry that dictates the boom cross-section shape was informed by parametric studies to optimize the parameters that most influence the cross-sections area moment of inertia and torsional constant. The corrugated designs were found to improve the boom bending and axial strength and to shorten the length of the boom transition from flat/rolled to deployed.

The new SMC substrate has four components: a shape memory polymer separately developed at NASA Langley; a stack of thin-ply carbon fiber sheets; a custom heater and heat spreader between the SMC layers; and integrated sensors (temperature and strain). The shape memory polymer allows the as-fabricated substrate to be programmed into a temporary shape through applied force and internal heating. In the programmed shape, the deformed structure is in a frozen state remaining dormant without external constraints. Upon heating once more, the substrate will return slowly (several to tens of seconds) to the original shape (shown below). The thin carbon fiber laminate and in situ heating solve three major pitfalls of shape memory polymers: low actuation forces, low stiffness and strength limiting use as structural components, and relatively poor heat transfer. The key benefit of the technology is enabling efficient actuation and control of the structure while being a structural component in the load path. Once the SMC substrate is heated and releases its frozen strain energy to return to its original shape, it cools down and rigidizes into a standard polymer composite part. Entire structures can be fabricated from the SMC or it can be a component in the system used for moving between stowed and deployed states (example on the right). These capabilities enable many uses for the technology in-space and terrestrially.