For more detail this asset from the Unity Asset Store: Click Here
This is a paid asset, but now you can download Planet Expansion Pack 01 (SPACE for Unity) for FREE, Please keep in mind this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Planet Expansion Pack 01 (SPACE for Unity) v1.0
“If possible, please buy the package to support the developer”
NOTE If this download link require a Decryption key, please enter this key: KMX-SQTN1oqSvEub27ewHfDxmpSgaSUe5oX2YojjEpc
This is an expansion pack to SPACE for Unity – Space Scene Construction Kit
Contains:
> 28 planet textures
> 4096×4096 Diffuse + Normal maps
> City illumination maps for earth-like planets
> Lava illumination maps for molten planets
Watch YouTube HD Preview Video
(The space backgrounds and atmospheres in the screenshots and video are part of the SPACE for Unity package that this expansion pack is intended for)
