Here's a dumb idea:

Could you drill a tunnel that's basically a chord (line between two points on a circle) that runs through the Earth between two surface locations, put a fully evacuated Hyperloop type system into it, and fire objects into space with maglev acceleration? It would be a full vacuum until the object neared the exit end at which point it would open. Air would rush in of course, but the object would need a heat shield anyway and would have to be traveling many times faster than escape velocity.

I guess it's a variation on gun launch.