Hd Realistic Mars
Rig
You can control Mars, the Camera and the Sun using the armature.
The circle controls Mars, with indicators to know where is facing.
The little cone controls the Camera.
The rays controls the Sun (you only need to rotate it, the position don't have any effect since the light source is located on an infinite distance).
Shader
Blue Atmosphere controls the visibility of the (very thin) martian atmosphere (example).
Storm adds a planetary storm weather to Mars (example).
Storm IOR controls the shape of the storm.