Nitpick, but your space station isn't going to have walls that are several inches of steel and several inches more of Kevlar composite, so for an equivalent siz

Nitpick, but your space station isn't going to have walls that are several inches of steel and several inches more of Kevlar composite, so for an equivalent size, it would be much much lighter. Agreed with your main point that we need to start manufacturing in space to get to very large scale habitats, though.