The first version of the Death Star was only 160km in diameter, which makes it more like a large asteroid than a moon, and too small to have any significant natural gravity. If the Death Star rotated once every nine minutes, this would be enough to generate 1g of centrifugal force at the surface, but this would point outwards. Instead, the Death Star has artificial gravity that points towards the core for the decks nearest the surface. In the central section, all the decks use a separate gravity that points down towards its south pole.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.