For me , and to add realisim to orbiter
1 Collision detection
2 Surface mesh
( eaven if it is only localy established around bases at first )
I have tried to build a mesh for my Mars Base in Solar nations
but can not seem to get it to follow the planet curve ?
I have seen this done with Shadow Base but this only covers a small area while
Federation Base is huge ( many KM ) There is a shipyard Bay 6 km long
may be some one has a way to do this