alt Hacker NewsI studied material science in school specifically to try and address his concerns. Unfortunately they are all quite valid - the hard part isn't manufacturing, extruding, printing. Those are actually all quite reasonable (albeit not super space or weight efficient). The hard part is refining and ore enrichment, and most techniques that could possibly work in microgravity are almost impossible to test on earth. You would certainly need vitamins for electronics components for a time. Even much older computer chip architectures (1990s level) still require the clean room and 20-30 stages of prep. I believe an orbital chip fab is not only possible but, kind of ideal? Keeping it clean would be within reach - and it's mostly if not entirely an autonomous process from silicon monocrystal to assembled part today.
We're along way from self replicating probes. But I would argue were quite capable of autonomous mining, manufacturing and material transport - assuming we can figure out how to refine effectively. If someone wants a cool PhD project and ship an experiment to the ISS, I would argue an ionic or plasma based refining technique designed for micro gravity could be very interesting and very useful
> Every terrestrial concentration process relies on things an asteroid lacks: gravity-driven sedimentation, water-based flotation, density separation in fluids, atmospheric combustion.
That's a good point. Most bulk industrial processes won't work in zero G. This limits asteroid mining. Breaking off pieces of rock and accelerating them to somewhere, maybe. Building a big wheel and spinning it up to get some gravity, maybe. Materials processing in open space, not so much.
The "seed" to start up an industrial economy might be the size of the industrial base of, say, Israel or North Korea, both of which try to be self-sufficient. We get to find out when someone tries to do something self-sustaining on Luna or Mars.