What techniques should I use to improve texture detail close up?

Unity Engine
1

I have a 2048*2048 texture of a section of the moon mapped to a plane. As the camera starts off a fair way above the plane the plane and texture look really good, but as i descend to now actually be stood on the plane, the texture looks horrible up close, no detail, blurry and well just plain not very good.

My question is what techniques could i employ to make the ground look good when the camera is near the floor plane?

2

You could add a detail map, give it some graininess.