My son was watching Star Wars and asked me if a large 'Death Star' object could actually be built in space. I thought of the many difficulties in standard construction techniques and thought of a possible solution .... Critiques welcomed of course.
Lets say a very very large inflatable 'balloon' mylar or indum / aluminized sphere is inflated with a compatable 'sputtering gas'. A port extending from the external space outside, to the internal center carrys a feeding conduit that presents a sputtering target material and a rotating cathode that is fed at a controlled rate.
The material sputtered to the walls of the sphere will slowly build up to a good strong mechanical wall thickness so after several years the shell could be filled to a near atmospheric pressure for occupancy and work.
Power can be from solar cell or a nuclear pile source.