Is the conquest of space going to be done floating in tin cans or can we find ways to build bigger spaces in space? It is difficult to avoid the fact that size is important. The volume of habitable space aboard a space station governs directly the number of crew and consumables, such as oxygen and food, that can be accommodated and the amount of equipment installed. The size of the solar arrays governs the power available to the station and the size of the radiators determines the amount of waste heat that can be radiated: there is no conduction or convection in space to help the process. The problem the space industry faces is that there is no known way to launch large, ready built structures from the Earth. The answers lie with techniques being developed for construction in orbit. The first step towards these larger structures would be to augment the `kit of parts' construction philosophy with methods that rely on building big things from relatively small elements, analogous to building a skyscraper out of steel beams bolted together. Another approach is to pack the module into a small space and unfurl or expand it in space. The approach lay behind the TransHab module, a Kevlar-based, multilayer inflatable structure.