Re:seems disconcerting (Score 1)

I would agree, however, it seems a lot of people are forgetting the simple fact of how bloody cold (and hot) it is up there. The tiles are going to contract along with the gap filler. Upon entry into the exosphere and then thermosphere the tiles, in theory would expand. The gap filler is probably more of a lower heat protection measure between space and exosphere. By the time the belly of the shuttle is fully heated those tiles are going to be squished together and riding on a wave of plasma.