It's hard to say with certainty, but at least some of the org will disappear when the game releases. There are quite a few that are counted among the 15,000+ that are here because it's the coolest place to hang out while the game is in development. Inevitably, people are going to want their own path and to make a name for themselves as an individual or smaller org.
So when it comes time, I don't know if we will have 15,000 org mates with which to populate even a smaller moon. These moons are shockingly huge. Maybe we will be looking at a larger asteroid. Maybe we will be looking at a collection of smaller asteroids and space stations that we will use to establish a universal presence instead of settling for just one sector.
To be honest though, I seriously hope that you will be able to purchase an entire moon or planet. If they allow this, I will definitely be buying my own planet. I'll name it Bob... Planet Bob.