Well, it takes a little explaining really.

Nova was originally GMed by only one person (first Proffer, then Dervish) but the current iteration does not use that method.
Rather than having a single GM guided story, we instead have the collection of characters, and players may submit mission ideas. The time in between the missions is spent with no GM and onboard the Tyrus, but each mission has a GM in the form of the player who's idea it is.
For administration type things, it is often put to the OOC and we work out a consensus between those present, and whoever owns the OP is responsible for editing it to stay up to date. Because Nova was a closed RP between friends, there were no disputes to resolve and no GM was needed for that role.