[hchutch]

NASA had a system they tried out (caulking gun), but there was a reduction in the safety margins of the tiles. Still, it might have mitigated the major problems. Colombia would have gotten down, but they'd still have had to scrap the orbiter.

[Mo1]

NASA had a system they tried out (caulking gun), but there was a reduction in the safety margins of the tiles,

I haven't heard of this .. but there is still the problem of going out into space to fix the problem

It is my understanding this was not possible on the Columnia