In truth I've been waiting for this one for a long time. Developer Diary #58 has finally introduced the concept of space habitats. That is to say, now instead of space stations serving as defensive platforms and areas to build your armies and fleets, now we're going to see the AI-species around you building their own miniature Ring Worlds. Which is the basic idea behind the space habitat, and it allows a way of peaceful expansion later on, presenting an alternative to the previous way of doing things, which was exclusively to expand via brandishing the pointy end of your sword.
According to the Diary these habitats will cost a small amount of influence and a whole lot of minerals and can be built around any planet or asteroid that is in your borders and automatically take on the attributes of a Gaia world. Anyone can live there, even if they're not from your species because it's a closed environment as opposed to a naturally-occurring planet in the game. You do not have to colonize the planet they're orbiting, meaning you can go straight to the orbital platform and leave the planets below alone if you want but this is a late game technology so the chances of you doing that will be slim.
In order to build a space habitat,you need to have researched the maximum amount of technology that can be put towards your space ports, like all the different modules that give you the fleet, food, and energy bonuses. But you also need to have picked the 'Voidborn' Ascension perk (for more information on those, please look at one of the the previous Dev Diary installations, I promise you wont regret it.)
All in all, Banks 1.5 and the as of yet unnamed accompanying update promise to be some of the biggest, and best, improvements to the main game of Stellaris that we've seen yet and I eagerly await its arrival.