Orbital shipyard

Spacecraft construction yard orbiting a planet. Doing this overcomes problems associated with gravity, craft size and locating a yard on the planet. Basic materials are normally freely available from asteroid belts and many more materials or spacecraft components are possible to make (they may not be possible in a gravity field). Using tech such as space busses or trans matter tunnels, yard crew live planetside and only work in space. That reduces material and support costs associated with them.