The Big Engine That Couldn't

By Natalie Angier

With four seconds left, a bad valve scrubs a shuttle debut

After a series of exasperating delays because of a slipped thermal shield and a computer blackout, the new space shuttle Discovery sat perched on its Florida launch pad last Tuesday morning, its nose poked impatiently toward the sky. In a chase plane high above Kennedy Space Center, Astronaut John Young took a last look at the weather and gave the final O.K. for takeoff. The shuttle's on-board computers began the final countdown. "We are go for main-engine ignition," NASA Commentator Mark Hess announced. The engine grumbled noisily, snorting smoke and fire... Six, five, four...

Suddenly Hess interrupted in a flat, unemotional voice, "We have an engine cutoff." Seconds later, NASA officials watched in helpless dismay while their proud young ship sputtered to stillness like a jalopy running out of gas. Concluded Hess stoically: "We have an abort." Nor was that the worst of it. As the astronauts lay strapped in their seats, awaiting instructions, hydrogen gas gathering in the ship's main-engine area burst into flames below them, shooting a tiny inferno through the engine pit. Sprinklers on the launch pad immediately flooded the pit with several thousand gallons of water, dousing the blaze in less than five minutes. Half an hour later, led by Judy Resnik, 35, who was scheduled to be the second American woman in space, the six astronauts emerged from the craft, some looking grim and weary, others with grins and wisecracks. To their bitter disappointment, they were told that they might as well head home for the weekend. Admitted Thomas Utsman, director of shuttle operations at Kennedy Space Center: "This will not be a one-or two-day turnaround."

That was a typical NASA understatement. Agency engineers soon realized that assessing and correcting the problem would take at least ten days, and possibly much longer. By week's end they traced the shutdown to a faulty valve in one of the shuttle's three engines, as well as to the perfectionist main computer, which oversees all auxiliary computer systems on board. When it detected that the valve was sluggish in opening, it automatically shut down the entire operation, as curtly as it might flick off a light (see box).

The scrubbed mission may be the biggest snafu in NASA'S glitch-plagued shuttle program. Never before has a countdown been interrupted after a main engine was ignited. Once engines are sparked and combustible materials released, the likelihood of a launch-pad tragedy escalates dramatically. As it turns out, experts who studied high-speed film of Discovery's firing taken right before shutdown believe that something was burning that should not have been. Normally, the liquid hydrogen and liquid oxgygen that combine in the engine nozzles to fuel the shuttle at takeoff produce billows of clean white steam. The film shows reddish-orange streaks in the clouds, a sign of burning plastic.

What would have happened if the engines had fired uncontrollably, or if the computer system had failed to respond rapidly enough to the flawed valve? First, the two solid propellant booster rockets, each as tall as the Statue of Liberty, would certainly have been ignited. Designed to augment the main engines three seconds after liftoff, the booster rockets would have catapulted Discovery with a thrust of 6 million Ibs. into a perilous runaway flight path. At that point, Shuttle Commander Henry Hartsfield would have had a daunting Luke Skywalker-type task, thus far confined to computer-simulation training: jettisoning the solid boosters once their fuel was spent (about 2 min. later), dumping as much auxiliary fuel as possible and then pitching the shuttle into the blue Atlantic.

Discovery's abort could not have come at a worse time. The agency was counting on the twelfth shuttle mission to demonstrate, among other things, the commercial potential of space. One of the six crew members is Charles Walker, 35, an engineer with McDonnell Douglas and the shuttle's first ambassador for private enterprise. Walker's in-flight task is to concoct a mystery drug for Johnson & Johnson, using a technique called electrophoresis, which in the zero gravity of space can separate biological compounds 700 times as efficiently as on earth. Judging by the many clues the principals have dropped, the substance could be a one-shot cure for diabetes. NASA had hoped that if Walker returned from the seven-day mission with a marketable product, other big companies would be prompted to rent lab room on the shuttle for projects like growing ultrapure crystals or shaping exquisitely round latex spheres for calibrating instruments. In a long-range appeal to the private sector, Astronaut Resnik hopes to deploy a 102 ft long, 200 lb. retractable solar "sail." The portable array of solar cells is the type of power generator that may some day provide electric power for NASA'S manned space station, including adjacent floating platforms suitable for extraterrestrial manufacturing.

Yet if there is one thing that entrepreneurs demand of their suppliers, it is reliability. And so far, NASA has offered anything but. Not only have 75% of the missions been delayed, but the unpredictable weather in Florida may foil the agency's plans for regular landings at Kennedy Space Center; shipping the shuttles back from Edwards Air Force Base in California adds time, money (about $500,000 a flight) and scheduling hassles to the program. Worse, NASA continues to be haunted by the disastrous satellite launches from the shuttle last February, when boosters designed by a private contractor sent two communications vehicles into uselessly low orbit. Telesat Canada pulled its satellite off Discovery because of worries about the booster rocket. In May a private European space conglomerate successfully launched its first satellite aboard the launch vehicle Ariane; the satellite, embarrassingly enough, belonged to GTE, an American firm.

Even the Pentagon is threatening to deploy its spy satellites with proven Atlas-Centaur and Titan expendable rockets, and is proceeding with plans to build its own version of a manned space shuttle.

As NASA struggles to trouble-shoot its new craft, the other flights scheduled for 1984 will be pushed back. That includes a late August mission; a particularly noteworthy launch in October, when Sally Ride will journey forth with Kathy Sullivan, who will attempt a spectacular spacewalk to refuel a floating satellite; and flights in November and December. These delays compound existing cutbacks from the twelve missions originally planned for 1984 to seven at present, to who knows how many by year's end. As for 1985, NASA still plans twelve.

Amid the gloom, there is one bright spot: the effects of the engine fire turned out to be inconsequential, in some ways less damaging than the normal trauma of re-entry into the atmosphere. Apart from a 25 sq. ft. section of insulation paint on the shuttle's aft side that was warped and charred (and is easily replaced), the shuttle is in good shape. Says Veteran Shuttle Engineer John Talone: "Basically, the bird looks like it did when we went in the first time. We are on a steady track to where we are going." For Discovery, a grounded bird now, that place is in the inky blackness above the sky, where it can become at last the faithful space truck it was meant to be .

-- By Natalie Angler.

-- Reported by Jerry Hannifin/Kennedy Space Center and David S. Jackson/Houston

With reporting by Jerry Hannifin, David S. Jackson