A solar array that deploys itself

Deployable systems usually pair a passive folded payload with a network of motors that unpacks it. This work embeds the actuation in the material instead: a functional metamaterial of wedge-shaped unit cells, each one arm of an elastic "flasher" origami joined to a pair of scissor mechanisms, with shape-memory polymer distributed through both. Below its transition temperature the printed array is stiff in either state; warmed past it, the stored prestrain relaxes and the array deploys on its own - a tenfold area expansion in under 40 seconds, in close agreement with simulation. Studying the folding dynamics revealed a bifurcation between collapsing into a disk or a cone, and the kinematics were optimized to carry the largest number of flexible solar panels.