We used to drop quarters from 2 feet onto the tiles and study the damage. They are very fragile. One goes, and the rest downstrean start peeling off. Stuck on with fabric like material to let them move around a little without cracking off. If they are THIS fragile, I'm aghast. All they have to do is hit one teeny tiny little piece of space junk and they're history.
One piece of space junk at 18,000 mph takes out the Shuttle or the ISS wherever it hits.