Death Star or ?
Believe it or not, this is Mimas. One of Saturn's smallest moons. It was discovered in 1789, but only seen as a small blip until 1980 when NASA's Voyager mission flew by and took close up images. So...Star Wars came out in 1977 and there's no way anyone knew, but perhaps the force was strong with the Star Wars production team.
May the Fourth be with you!