Running a space-based campaign is difficult, because there is no central point, no home town. You can have a Shadowdale or Waterdeep as a home in the Realms, a place where you know everyone (if not trust everyone). Where you can stock up and recover and repair and maybe get a house to put all your stuff in. In space, the role of your house is taken up by your ship, but then where do you interact with others? Pick up stories? Go out for a few drinks?
Hence, a (semi) portable city, suitable for placement in your campaign setting. A place where other spelljammers can dock, where adventures can begin, and where adventurers to retire to. The shape of the map gives it a general Waterdeep vibe (longer than it is wide), but the nature of space and what has been termed "Grubbian Physics" created a different world indeed.
|Get a Piece of the Rock|
The idea was to create a city which could be plugged into any campaign that takes up spelljamming. In the Realms it is the Tears of Selune at the moon's trailing Lagrange point. In Greyspace (aren't you glad we didn't call it Oerthspace?) these are in the asteroid field called the Grinder. It had a utility that went beyond most city settings, because it benefitted from not having to have ties to the surrounding area. Space has that advantage.
The city is also a bit darker than a lot of terrestrial fantasy campaign cities. The current Prince is in power after his elder brother mysteriously died (and was found floating out in space), and those who were punished for the crime may not have been the true perpetrators. Major crimes are often winked at by the authorities unless they see their own advantage is prosecuting them. And, unlike a lot of cities, there are racial districting, where the halflings and gif may be found (the gnomes, oddly, seem to be everywhere). It is a grayer world, hopefully evoking Tortuga and Port Royal more than a fantasy London.
The end result is a novel little chunk of land floating in space, with a portability that can make it a guest star in other campaigns. Its a pretty cool concept, worth checking out.