If I was setting out to do it, I'd think about a three part system. First would be the gun on the surface, the second would be a launch vehicle, and the third w

If I was setting out to do it, I'd think about a three part system. First would be the gun on the surface, the second would be a launch vehicle, and the third would be a satellite in orbit to act as a target. The gun fires the launch vehicle at the target. The satellite (I picture it as a donut, with the projectile aimed at the center) uses an electromagnet to "fix" the launch vehicle's orbit. Aside from whatever physics I am ignorant of, I think the big question mark here is power as I would expect the draw of the magnet to be beyond what you could plausibly provide with solar panels. It's also questionable how well this would scale. It doesn't seem like something you would ever think of using to launch crewed vehicles or things like the Hubble, but if the marginal cost of your launches is low, it seems like individual cargo capacity is less important. You could launch raw materials, small parts and assemblies, and maybe even things like human consumables.