Okay, I've just written a general description of the system, asteroid, and facility on the asteroid along with the mentioning of our current planet. I'll try to get it typed up soon but here's the general idea I went with: the system is a living being with a mind of its and the asteroid facility is a combination mining facility, travel hub, tourist district, and city (I haven't described the facility much other than arrival area, I'm not good at creating cities ).
For the arrival area, we've got a landing pad and a checkpoint. The landing pad is flanked by two buildings: one is a teleportation hub and the other is a series of doors with a gateway in the dead center. The doors each lead to a different spatial dimension while the gateway is the centerpiece of the room and provides a way for anyone who travels via other means to arrive. It doesn't redirect people when they enter a portal, just gives them an option allowing for them to go straight to a different place in the system if they wish.
The system lies in an area in which the space-time continuum is unstable, allowing it to exist anywhere and everywhere. It is a young system with only one planet and various satellites but desires more.
Let's add some more stuff in the hub for people. It helps to have a place for all the characters to interact in before they think up a good adventure.
We can also think up a handful of characters who work there to flesh it out. The way we handled that in the Inn was to make up a staff that anyone could play. So...a Customs officer, for example. Maybe a scientist who maintains the Hub. The owner of a hostel where people can sleep. Things like that.
*thinks some more*