[The Westerner]

"In fact, he said they can't even inspect them while they're up there, which is why NASA had no information about whether any tiles had been damaged by the debris which hit the wing on take-off."

This doesn't make sense. When the astronauts go outside for spacewalks, couldn't they inspect the tiles?

[GovernmentShrinker]

No, Dittemore explained in detail why they couldn't. They aren't able to go very far on their "walks" -- only to the immediate vicinity of the payload bay.