Down at Cape Kennedy, Columbia lies in an assembly hangar, imprisoned in scaffolding. Arc lights gleam off its impossibly smooth surface. They shine round-the-clock, as 500 technicians work double ten-hour shifts, six days a week, trying to make the shuttle spaceworthy. Columbia was supposed to be finished last March, when it was transferred from the factory of the prime contractor, Rockwell International. Instead, it arrived at the Cape only 75 percent complete, according to NASA. No one is certain when--or even if--the remaining work will be finished.
The drydocked Columbia represents at once all the shuttle program's problems. They are: delays; cost overruns; performance underruns; and lack of work for the horse to do. Delays, the least important problem, are the easiest to understand. "People don't appreciate that the shuttle, as a technical goal, is much more ambitious than the moon program," says Eugene Covert, an MIT professor and rocket-propulsion expert. "The schedule couldn't possibly have been met."
Considering what the Columbia is supposed to do, it's no surprise that it didn't fly in 1977, or in 1978, or in 1979, and it can't fly yet in 1980. The rockets it is supposed to replace have always been throw-away affairs for very pragmatic engineering reasons: the fiendish forces of space flight twist and sizzle machines into scrap. Rocket engines are essentially explosions with a hole at one end. Exploding gases roar out the hole, shoving the rocket in the opposite direction. The act of firing does such violence to the rocket engine, immolating and warping its components, it's impractical to use again even if you can get it back. Yet the shuttle's main engines will have internal pressures three times greater than those of any previous large engine, NASA says--and the goal is to use them on 55 flights before an overhaul.
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. All this mounting was supposed to be finished before Columbia left Rockwell's factory. When it wasn't, the work had to be resumed at the Cape. "We've had to put up what amounts to a manufacturing facility there," says Walter Kapryan, who retired as the Cape's shuttle project director last spring. "The most we ever did for Apollo was a little patch-wiring." NASA sources privately acknowledge that Columbia was taken to the Cape in unfinished condition partly for public-relations value--to make it appear that preparations were accelerating.The move also allows computer testing to proceed while the tiles are being mounted. This exercise may have been practical, but it was staggering in cost: $50 million extra to attach the tiles at the Cape, according to congressional sources.
Some suspect the tile mounting is the least of Columbia's difficulties. "I don't think anybody appreciates the depths of the problems," Kapryan says. 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.)
According to the computers, as long as you can bring the shuttle back into the atmosphere, you can fly it to the airfield even if the tiles are damaged. Former Apollo astronaut Richard Cooper doubts the computers know what they're meeping about. Many of the projections are based on the magnificent accuracy of the Apollo landings. Apollo went to the moon, came back, and dropped all its little manned modules into a target area about the size of Los Angeles International Airport. But Apollo modules were ballistic projectiles. They were slightly asymmetrical and thus had a little lift for control, but basically they fell like well-aimed stones. The science of ballistics is much more precise and predictable than the art of flying. To assume that experience with one is the same as experience with the other is to confuse a slingshot with a seagull. The only way to find out about something as big and balky as Columbia, Cooper says, is to launch the thing and see what happens. Computers have never flown with the unpredictable combination of damaged tiles that a shuttle may experience. They've never been whacked by a sudden, nonprogrammed gust of jetstream wind. They've never flounced like a twig on the crazy rapids of "bias"--the bland physics term for unexplained variations in the earth's gravitational and magnetic fields. These are the wild, uncharted rivers of space. Unknown; unknowable; beyond programming. To find out if your ship can cope with them, you have to take it up there.
For the full text of the original 1980 article, click here.