re: And Resources are what motivates space exploration?
It seems to me raw materials are less of an issue than they used to be, as long as they are processed in such a way you'd need less of them.
Cars don't weight as much as they used to. Neither do planes.
We use less material but we use it more intelligently.
One of the main problems sending anything to space is weight: therefore, any engineering idea to do the same or more with less mass, is better.
And there's nanotechnology...