Actually happened to me once or twice (places where you can time-warp near the surface).If battery is not an issue, its most likely you are on a time-warp but can still move your craft even though its technically impossible(possible bug/glitch?). It's really nothing to be worried about and you'll mostly likely never encounter it again, but just to be on the safe side, you should always quick save whenever you're doing something "drastic" because there are other bugs other than the one mentioned.