Back in 1980 Gregg Easterbrook predicted the problems we were going to experience with the space shuttle program. Now that 7 more lives are in danger, it might be good to think another time:
To truly grasp the challenge of building a space shuttle, think about its flight. The ship includes a 60-by-15-foot open space, narrow wings, and a large cabin where men must be provided that delicately slender range of temperatures and pressures they can endure. During ascent, the shuttle must withstand 3 Gs of stress--inertial drag equivalent to three times its own weight. While all five engines are screaming, there will be acoustic vibrations reaching 167 decibels, enough to kill an unprotected person. In orbit, the shuttle will drift through -250°F. vacuum, what engineers call the "cold soak." It's cold enough to embrittle and shatter most materials. During reentry, the ship's skin goes from cold soak to 2,700°F., hot enough to transform many metals into Silly Putty. Then the shuttle must glide along, under control, at speeds up to Mach 25, three times faster than any other piloted aircraft has ever flown. After reentry, it cascades through the air without power; finally thunking down onto the runway at 220 m.p.h. The like-sized DC-9 lands, with power, at 130 m.p.h. Rockets are throwaway contraptions in part so that no one piece ever has to endure such a wild variety of conditions. The shuttle's design goal is to take this nightmare ride 100 times.
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. Most of the technicians swarming over Columbia are trying to glue down tiles. The tiles break so often, and must be remolded so painstakingly, the installation rate is currently one tile per technician per week.
Well, the Columbia blew up in 1986, the Challenger in 2003. Easterbrook at that time wrote in Time Magazine The Space Shuttle Must be Stopped :
... the space shuttle was designed under the highly unrealistic assumption that the fleet would fly to space once a week and that each shuttle would need to be big enough to carry 50,000 lbs. of payload. In actual use, the shuttle fleet has averaged five flights a year; this year flights were to be cut back to four. The maximum payload is almost never carried. Yet to accommodate the highly unrealistic initial goals, engineers made the shuttle huge and expensive....
Capitalism, of course, is supposed to weed out such inefficiencies. But in the American system, the shuttle's expense made the program politically attractive. Originally projected to cost $5 million per flight in today's dollars, each shuttle launch instead runs to around $500 million. Aerospace contractors love the fact that the shuttle launches cost so much... Any new space system that reduced costs would be, to the contractors, killing the goose that lays the golden egg.
Just a few weeks ago, NASA canceled a program called the Space Launch Initiative, whose goal was to design a much cheaper and more reliable replacement for the shuttle. Along with the cancellation, NASA announced that the shuttle fleet would remain in operation until 2020, meaning that Columbia was supposed to continue flying into outer space even when its airframe was more than 40 years old!
True, B-52s have flown as long. But they don't endure three times the force of gravity on takeoff and 2000° on re-entry.