Was just thinking more about ballistically sending materials into Earth orbit today and wondered if maybe it would be easier to send them in smaller payloads but just send more of them and assemble in space. That is, you don't need to send a whole spacecraft in a single shot, but could send relatively smaller payloads which would reduce the size and cost of the railgun.
I wonder what the smallest ion engine is, because it seems those would be the ideal method of propulsion for assembling the various packages together into a specific orbit. I believe each of the hundreds of StarLink satellites have an ion engine.
Interesting, looks like they are called hall effect thrusters in the industry. They are capable of accelerating the propellant to 100,000 MPH.
https://en.wikipedia.org/wiki/Hall-effect_thruster