All rendered in realtime inside of inside Unreal Engine 4. Details below.
A total of 96 individual mesh pieces with a series of 4K textures on each make up a 65,536 pixel resolution around the circumference, with equal texture density and no seams. The textures themselves are re-projected from actual NASA images.
So far it features accurate cloud shadowing, atmospheric scattering, night/day textures, procedural thunderstorms and eventually proper normal mapping (there are some visual artefacts with the current normals).
This is being built as part of a cinematic mission control experience for a Satellite Control Station.