Nice shot from the dark side. The whole day/night cycle is a themed color system running through some advanced custom shaders.
This shot shows the day lighting. The sun follows the character around (it is always day during gameplay).
There is a lot of difficult angles that is to be considered. The darkness to the right shows space and stars while the dawn to the left is starting to get color and dim the stars. It was important to get the toony light/color feel as smooth and natural as possible. The shader decisions is based on camera angle, position and zoom.
The spaceview has its own color theme. The surface atmosphere turns off when the player is pinching out towards space.