There's no zones or loading or anything. Just a ship moving through tens of thousands of kilometres of 64 bit positional space.
You talk about the map size in Star Citizen as though they've managed to do something no one else has ever achieved before. This plainly isn't true, Elite Dangerous (although I haven't played it) manages to pull off huge star systems, SpaceEngine (free download) allows you to visit planets in other Galaxies, and upcoming titles such as Duel Universe are just as ambitious.
Regarding 64 bit positioning. Again this is nothing new, nor is it especially hard to do - just change all the float values to double. Space Engineers have managed to pull it off
http://blog.marekrosa.org/2014/12/space-engineers-super-large-worlds_17.html (note - that was 2014). Although, using 64 bit positioning may explain why the performance is so poor and the physics is a so jittery in Star Citizen (same problems in Space Engineers).
As far as I can tell, Star Citizen isn't doing anything technically different to many other games. There is no new technology, it's just standard industry stuff but they refer to it using different terms to make it sound like something they've invented. eg Subsumption technology for the AI - which as far as I can tell is just a fancy term for a Behaviour Tree - which they still can't seem to make work - by all means correct me if I'm wrong on this.
The only thing Star Citizen does differently to other games is their constant drive for FIDELITY - creating a fluid physics simulation for drinks, creating a whole system to deal with picking up objects, rendering every little bolt and fixture in high detail. The reason why no other game does this is because it's a performance hog and detracts from the actual gameplay. In that regard, Star Citizen seems to be a giant art project rather than a game, but that's just my opinion!