The inflatable structure is made of multilayer fabric and looks like an ungainly white robot with legs. The main unit is 12 feet in diameter and 18 feet tall. It has a volume of about 1,600 cubic feet and is connected to an airlock, also inflatable. The two spaces are essentially pressurized cylinders, connected by an airtight door. The concept design has been delivered to NASA Langley by ILC Dover for testing.