When you finish building Bright Hope, you may put a Ground card from your hand face down under it. If Bright Hope is discarded from the Space arena, put that Ground card face down in your build zone with 5 build counters on it.
You must reveal the card underneath Bright Hope at the end of the game to prove that it was a Ground unit (assuming it was not built during play).
If you have Bright Hope with a Ground card under it, then play Refit on Yavin on the Bright Hope, the card stays removed and has no effect afterward.