: Someone's been reading Ringworld :)
A long long time ago, yeah. But how else are you going to get a ship in or out of a hollow sphere containing an atmosphere? Any holes in the "ground" and all the air would go whooshing out (like the Eye Storm, for another Ringworld reference). There are smaller airlocks on the outside, and transporters and the like, but those are only useful for small things.
Then again, I suppose that this thing WAS built by the Jjaro... they could fold whole planets around, why not beam a ship inside? But I don't want to shoot holes in my own story, so... These are more ancient Jjaro, they couldn't do that yet.
