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Shuttle Surface More Vulnerable Than Suspected
Ant writes "The space shuttle's skin is turning out to be even more fragile than NASA engineers thought, its scientists and engineers say. Impact tests and analysis performed as part of the return-to-flight effort show that pieces of insulating foam that weigh less than half an ounce can cause small cracks and damage to the surface coating on the heat-resistant panels on the leading edge of the wing, agency officials said in interviews this week."
I don't think aging has much to do with it. As I recall, most of the surface components are replaced after each mission and everything is thoroughly inspected for defects/weaknesses.
It sounds more like a design flaw. The foam issue is something NASA had known about for a while before the Columbia disaster, they just hadn't taken it seriously enough. Kind of the same thing as what happened with Challenger where they knew about the o-ring issue but didn't take it seriously enough either.
Let me say again, this is NOTHING like dropping the pink-panther stuff out of your second story window and breaking a ceramic dinner plate that you left on the ground.
Upstairs Dog, Downstairs People.
Political pressure was put upon NASA to lauch a vehicle during this launch window. I forget the details behindwhat it was. If I remember right, there wasn't another window for several weeks if they missed this one.
Second, the O-Ring was blantantly known. There's a reason the demonstration the NASA Engineer put on, where he pulled the O-Ring out of water and pulled on it was so blantantly bad. It's my understanding from reading Richard Feynmann's comments that he insisted be added as an appendix to the report, that essentially the right people in NASA knew it was going to blow up. However, they justified it, with "Well the O-Ring is three times as thick as it needs to be, so the problem it is showing where it has a 1/3rd erosion is not a problem". You can read up on it here
Feynman essesstially accuses them of using previous success as a evidence that all future launches will be a success. That's not good science or good Engineering. I think Columbia was screwed from the moment they made orbit (they might have been able to abort pre-orbit, post foam collision. I'm not sure on that). However, Challenger, they KNEW, they had an important piece behaving oddly in a way they didn't understand, while launching under extreme conditions. That's not being particularly safe.
While I agree with you on Columbia, I strongly disagree with your characterization of Challenger.
Also, I'm absolutely positive those parts haven't been sitting in a warehouse since 1965. We were fairly busy with the Mecury and Gemini missions in that time frame. My guess is they got invented no earlier then 1975, and made no early then 1980 or so. I'd have to go look into the history, but I'm reasonable sure the drawing hadn't even been brought out before 1972 or 1973, screw making parts to a specification.
Kirby
Yes, they are new. One can't stock spare tiles since each is tile different. Not only are the tiles not interchangable, the orbiters don't have compatible tile layouts. So they are custom built as needed. Until recently they were manufactured by the original facility in Palmdale, California. This made sense since the shuttles were built there. A couple of decades after they stopped building shuttles, Nasa realised that it would make sense to move the tile manufacturing facility to Florida, right next to the orbiter processing facililties. As soon as they completed this new facility, hurricane Frances swept through Florida and ripped the roof off. So Nasa is currently considering whether to reopen the old Palmdale facility.
Note that "tiles" != "RCC panels". The former are cheap, the latter cost nearly $1m each. Nasa has spares of these (at least they are interchangable between shuttles), but new ones can still be built by Lockeed Martin. Though the staff are starting to look a little old...