[ExI] von Neuman machines

[Keith Henson]

I have recently had two people talk to me about replicators on the
moon and a robotic self replicating asteroid mining capability.  I
fear I rained on their parade.  After some reconsideration that might
not have been entirely justified because I have not thought seriously
about bulk state replicators for a long time.

The Wikipedia take on the subject is here

https://en.wikipedia.org/wiki/Self-replicating_machine

I read the article through and don't find substantial advances in
recent decades.  The article mentions the usual suspects, Eric
Drexler, Freeman Dyson, Nick Szabo, Robert Freitas and Ralph Merkle.

Question I have is:  Do any of you know of projects beyond what the
Wikipedia article mentions?

Alternately, do any of you have insight into solving the problems?  I
am particularly interested in proposals to take an asteroid, say a
carbonaceous chondrite and make it into useful materials to feed to
the replicator.

Best wishes,

Keith