Painting the Space Shuttle external fuel tank and Columbia.

I guess the first question is whether insulation came off the tank before they stopped painting it, and what that actual paint was; and what other changes were made.

I was kind of thinking the same thing about the paint being more cohesive than the foam.

the smaller factors I can see would include acceleration and flexion stresses from launch.

we have that issue with wooden ladders - they are not allowed to be painted other than a distinctive marking to show ownership.

the other side of it, you install the foam, then you inspect the foam, and then you paint it. you now have reason to believe any paint damage will include foam damage. kinda like on your car. if someone bashes a divot in the paint, you can assume that divot extends to the sheet metal underneath.

keep in mind that "old" was not a thing on the shuttle external fuel tank. they rolled it out of the factory, hung a shuttle on it, shot it all into space, and didn't get it back.

The two side Solid Rocket Boosters were reusable, the central main external tank was not.

For what it's worth, Columbia was struck by foam at about 80 to 82 seconds after liftoff. That puts it at roughly 700 meters per second, or darn near 1,600 miles per hour and accelerating greatly.

Here's the break down of a typical Shuttle liftoff (some variance based upon actual liftoff weight, of course):

www.nasa.gov/pdf/466711main_AP_ST_ShuttleAscent.pdf

Jet exhaust blown toward the test subject materials instead of using a wind tunnel?

Ones that are likely top, top secret so right, that's no good. Didn't think Columbia was that far down range when the foam broke free when I first considered this one. What about a lubwieg tube then?

shepherd.caltech.edu/T5/facilities/Ludwieg/Ludwieg.html

Maybe if foam breaks free if exposed to a supersonic blast from one of these but doesn't break free when it had been painted that seals the deal?

BUT - would need to thin down the atmosphere a bit to replicate the correct altitude... Thinner air has less punch against the foam... Air pressure about half sea level? Although, even if ambient room air pressures were corrected down to half sea level, when the blast of air hits (coming out of the tube) it would completely change to nature of the ambient air as high pressure air floods in, increasing everything. So, maybe the only way to know for sure is to fly rockets with foam and another with foam that has been painted, and fly them to 1,600 mph at about 18,000 feet AGL. What a drag!!!

Then again, if the math is done correctly, figuring for about half sea level air pressure at 1,600 mph may mean one gets the same power by a much slower air speed at seal level air pressures, putting us maybe closer to transonic speeds instead???