A Von Neumann machine could in fact build a Walmart. I am more
interested in getting a microwave system into space and solving the
world's energy problems.

Are Walmart going to sell me a digitally controlled machine tool so
that I can make all the parts that are no longer in stock? They clearly
have the technology!

To go to Mars economically you need facilities there, this is only
achievable by something like a VN machine. Anything else will cost
upwards of $80 billion.

http://groups.google.co.uk/group/rec.aviation.military/browse_frm/thread/1d7c010855caf1dd/074a60610c4da1bb?hl=en#074a60610c4da1bb