Quote Originally Posted by rvg View Post
Asteroids contain a whole bunch of common metals, especially iron. That's the point of processing them in space, since Earth already has enough of iron.
Except the metallurgy is a bit more complex than just being slabs of iron. I think the main material is aluminum but I am not 100% sure about that, but I do know that trying to achieve such metallurgy in space is a great exercise in expensive distasters waiting to happen. Space only gives you one shot at survival. Our space age shuttles have blown up before they even entered space simply because they launched on a very cold day. The tolerances needed are difficult enough to engineer and test on earth, let alone a zero gravity environment.