OMG.
I just had an idea thanks to you and remembering something from Chrono Trigger.
The bases will be on solid ground... they can even see each other, but can't directly access -- midfield will be orbiting over the planet/moon, via teleporters. OMG.
I just wish Q3A's engine could rotate skyboxes like Q2 and Unreal Tournament. One of the few things I liked about UT is it's weird skyboxes... that one orbiting space station map in the demo I played was out of this world.