Flickering realtime shadows and Lightmap bake crash.

I have big problems with a single directional light (sun) and realtime shadows.

I know it's a well known issue: unstable shadows (flickering)

But I can not use a near plane greater than 1 and not a far plane less than 450000 (i'm in the space). I would like to know if it was resolved in newer versions of Engine. I use Unity 5.1.1 version.

I avoid using the real-time shadows and trust to lightmap ... but unfortunately even here I have big problems with freeze and crashs that does not allow me to do a bake....

It 'a very important issue, I worki with my team from a year to our Space Sim.

There is a solution?

(sorry for bad english)