Graphene's tightly bonded impermeable single atomic layer of carbon offers unrivalled potential for lightweight flexible gas barrier applications. Graphene has been shown to be conductive, durable, flexible, and impermeable, ideal for wall material of inflatable space structures. SMI proposes to demonstrate the material as the principal material in impermeable gas/vacuum barrier fabrics for expandable space habitats and structures, and develop a low cost roll-to-roll production process. In Phase I, SMI produce 10x10cm graphene films and characterize them and refine the process for web production. SMI will also design a flexible, lightweight graphene-based multilayer barrier structure for space applications. In Phase II, the graphene roll-to-roll production will be developed and graphene-based flexible multi-layer impermeable barriers will be demonstrated.