"vincent p. norris" wrote:

this is the first I've heard of
a VN machine. Did he first suggest it?

The idea had been kicked around occasionally in earlier futurism and
SF. Alan Turing's "universal computer" (one that could in principle
emulate any computer) got Von Neumann thinking about a "universal
constructor" that could do all that *and* copy itself (and a bag of
chips).

In the posthumous _Theory of Self-Reproducing Automata_ he put a
clear focus on exponential growth and speculated about potential uses
in space, where there would be a premium in getting the most bang per
kg. from what we could afford to send out. Freeman Dyson has taken it
farther, suggesting that microelectronics and genetic engineering
could combine to yield space-going cyborgs that might (among other
things) gather and process asteroid resources so that later human
explorers would find water, O2 etc. waiting for them.

And, of course, there's a direct line from von Neumann to Drexler and
the nanocult. Even if one admits any limitation to what one nanobot
could do, it can be handwaved away with enough doublings.