The main cause of delay is currently the shuttle's refractory tiles, which disperse the heat of reentry from the ship's nose and fuselage. 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 long pole holding up the tent," says Mike Malkin, NASA's shuttle project director. Fixing them to the Columbia without breaking them is like trying to eat a bar of Bonomo Turkish Taffy without cracking it.
Read the rest of the April 1980 Washington Monthly cover story here. Via Raketenwerfer.