Rigidisation of deployable space polymer membranes by heat-activated self-folding

Current gossamer space structures such as solar sails usually rely on bracing structures, inflation gas, or centrifugal force to deploy and maintain a structural shape, which leads to a system that is sometimes complicated, while a concise system can be achieved if the gossamer structure could self-rigidise and support load. The present study proposes a self-folding polymer membrane based on space-qualified materials and is potentially mass-producible by industrial roll-to-roll processes. It can permanently transform a flat gossamer membrane into a load-bearing 3D configuration when heated by sunlight in space, while the folding-induced shape bifurcation and buckling are prevented using a kirigami hinge design. The shape transformation is demonstrated in lab by a tubular and an origami structure that are formed from a flat membrane when heated to 82 °\C in oven. Thermal radiation analyses have also verified the feasibility of sunlight-activated folding in space when vapour-deposited metallic coatings are applied onto the hinges. The proposed material offers a new generation of gossamer space membrane that can automatically morph from a stowed configuration to a load-bearing structure, and potentially provide built-in functionalities.