select a layout that has two panels side by side and have ur sphere in one and the make the other the uv editor. Now if u right click on the sphere and click UV's.

Now select the back uv's of the sphere and then in the uv editor just move them so they don't overlap with the front face uvs. just like pushing and pulling vertices.

Theres some great texturing tutorials on here that go into uv mapping for more complex objects, but that shud be a quick fix

hop it helps