gregg easterbrook

Gregg Easterbrook (who has one of the truly odd job descriptions in journalism: liberal policy-wonk writer by day, cheerleader-happy football columnist by night) predicted the Columbia’s demise back in 1980. (At least if you’re a supporter of the tiles-did-it theory.)
Columbia must be fitted out with 33,000 of these tiles, each to be applied individually, each unique in shape. The inch-thick tiles, made of pyrolized carbon, are amazing in two respects. They can be several hundred degrees hot on one side while remaining cool to the touch on the other. They do not boil away like the ablative heat shieldings of capsules and modules; they can be used indefinitely. But they’re also a bit of a letdown in another respect — they’re so fragile you can hardly touch them without shattering them.
The tiles are the most important system NASA has ever designed as “safe life.” That means there is no back-up for them. If they fail, the shuttle burns on reentry. If enough fall off, the shuttle may become unstable during landing, and thus un-pilotable. The worry runs deep enough that NASA investigated installing a crane assembly in Columbia so the crew could inspect and repair damaged tiles in space. (Verdict: Can’t be done. You can hardly do it on the ground.)