Not quite Mars, I’d have used NASA textures for that, but this planet is fully procedural (neither image textures nor color ramps!), and colors can be easily modified.
Sure!
The planet’s shader is a simple Principled BSDF with roughness set to max and specular to near its minimum
I then plug in some textures into the color and normals
The textures are the fun part
They are essentially musgrave textures set to multifractal or ridged multifractal distorted by a multifractal musgrave, some Power nodes and math to blend them, some voronois distorted by voronois for the craters, and a bit of white noise for the bump map strength
The crater node group is pretty simple:
The atmospheric shader is just some vector math with the position plugged into scatter and absorb volume nodes, plus more of the distorted musgraves for some subtle clouds
