It's my understanding that the ship has subjective gravity, in that it has gravity where and when we as writers want it to. Specifically I just assume there's going to be gravity anywhere people need to go. I also imagine more than just the flight crew and pilots go into the hanger and that it has gravity most of the time, and its turned off for large scale launches and operations, like the one we're embarking on with the potential need of a full complement escort.