How to shadow a large rotating space station?

I need to create a scene with a spinning space station. This movable actor is 30km (18 miles) wide and the player can see it all from a distant, or enter inside seamlessly.

The scene is illuminated by a single directionnal light. I’m looking for a solution to get both sharp shadows at close range and rough shadows in a 50km range radius without performance issues, if it is possible.

I’ve read the lighting documentation but I’m not a UE4 shadowing guru… Could you help me on this or point me existing exemples?

Downscale the whole scene to something reasonable and use conventional cascaded shadow maps coupled with far shadow cascade.