The planet in the background of the space biome does not appear for the first half of the cycle, then appears at the top left of the screen halfway through the cycle, and follows a very strange looking arc towards the middle of the screen until it disappears 3/4ths of the way through the cycle. Exact timing and path the planet followed changed when I tested in a new save file, but results are approximately the same. Similar issues happen in both the base game and Spaced Out.
Image 1: Planet has just popped in
Image 2: Planet about to disappear
Image 3: Planet gone
1: Open any game where space is visible
2: Watch the sky for a cycle