The current end-game story line says that the colonists are in thermosleep somewhere in deep space, and you have to construct a space ship to fly there and get 'em.
But the devs have received some bad critizism for this and are thinking of rewriting it, but quote, "I will never give up the spaceship building "
Now you don't have to! Low- Orbit and upper-orbit factory designs are just an idea away!
- Send rockets to space to build platforms for extraterrestrial manufacturing goodness.
- Build cleanup drones to collect space debris for resources and to clear the path for future incoming colony ships!
- Build spaceport/spacefountain/space elevator for space refueling and space resupply!
- Build solar satellites which can send power planetside with power relais. (Power relais might also be able to send power starside and back so you no longer need to build all those large electric poles. Just one sender relais, a receiver and a relais satellite.)
- But what is this? The colony ship is off course? Build homing beacon to get the lost sheep home.
- Send yourself to the next moon or planet? Why not? Just be sure to research deep space exploration, terraforming and artificial life support first. Which you can only do in space laboratories. IN SPACE!
- Really, really large biter colonies won't stop nibbling on your turrets? Orbital weapon platforms are your friend! Laserbeam, ion cannon, kinetic bombardment or nuclear weapons launcher? Don't pretend like you dislike the thought of letting the sky fall on your enemies.
It would be debatable in how far you need specialized equipment for the spce base (do conveyor belts really work in 0G? Furnaces without air? Do you need to build a space platform for all your equipment, or could some of it be able to just float about?), or if you need a special runway to bring ressources back planetside.
Did I forget something? What about ressources that can only be found in space?