“The RepRap community is developing a printer using an electron beam in vacuum to melt powder to shape layer by layer. This machine will also be able to print solar panels. What is needed if we want to go deep space is a transistor printer (circuit board printer is more or less done), so we can have logic gates, CPU’s, memory etc without having to ship it from earth.”

“A factory in space complete with “assemble bots” that puts together the parts coming out of the printer, that should work indefinitely (since it can build itself multiple times before nearing the end of its lifespan) given a steady flow of processed raw materials. The idea here is to send up a complete system already loaded with raw materials to an ideal spot in/near the asteroid belt. You also send along an already built processing station for raw materials and some “mining bots”. When the system deploys, the mining bots will start collecting metals, water (to convert to oxygen and hydrogen for propulsion) and other materials needed. The processing station enriches/converts everything into appropriate format requested by the factory.”

“When you have sent a couple of system to different seeding places in the solar system, this will give an absolute material abundance, not only on earth but everywhere in space. We will also have a complete map of the solar system, down to the smallest asteroids and we will be able to catch incoming extrasolar objects instantly. And as Moore’s law states, in the next ten to thirty years (when this system maybe could be deployed) we will have computers hundreds to thousands of times faster than today, which will enable us to simulate the orbit of each and every little asteroid, enabling us to predict with great accuracy how objects will behave, and enabling us to really see the butterfly effect of a large object entering the asteroid belt, etc.”

http://reprap.org/wiki/MetalicaRap
https://en.wikipedia.org/wiki/Self-replicating_spacecraft