People keep asking whether 233 means something technical. It does not. It is the code you dial to reach Ghana, and that is the entire point.
Most science fiction set in space quietly assumes the future is furnished by somewhere else. You can usually tell within a minute of the opening shot whose future it is. I wanted a world where you can tell within a minute too—and the answer is here.
Naming it after the calling code was the clearest way to say that. No mythology required. Just a number people already dial when they want to reach home.