A Failed Experiment Succeeds in Proving Something
It is sad but true that some of the most promising achievements of the nation’s space program have been overshadowed by its failures. Sometimes, the two have come hand in hand.
When a $443-million Italian satellite broke free from its tether and drifted off from the space shuttle Columbia last month, a bold experiment was said to have ended in failure. And while it is true that the loss of the sophisticated satellite is a disappointment, the experiment proved that a few visionaries had been right all along.
It has been nearly a decade since I first met Ivan Bekey, a brilliant scientist whose ideas sometimes seemed to intimidate his employer, the National Aeronautics and Space Administration. Bekey was kept in a corner office at the end of a long hall, almost as though NASA hoped nobody would remember he was there.
The oddball ideas that seemed too preposterous to be true but too promising to ignore were sent down the hall to Bekey, where he was supposed to decide what to do about them. But Bekey had a few ideas of his own.
One of them was to attach a mass at the end of a long tether connected to an orbiting spacecraft. As the tether, acting as a conductor, swept through the magnetic field that surrounds the Earth, Bekey thought, an electrical current would be generated that would flow down the tether.
During our first conversation so long ago, Bekey became so excited when talking about the tether that he rose from his chair and paced the office. Such a concept held the possibility of boosting a spacecraft’s orbit by using electricity generated by the Earth’s magnetic field to run electric propulsion motors. That could reduce the reliance on small rockets that pollute the ionosphere, thus clouding the results of various experiments.
But Bekey was faced with a hard sell. A mutual friend reports that when Bekey presented his ideas during a symposium at a Los Angeles-based aerospace company several years ago, one executive became so distressed that he stormed out of the meeting. The problem, our mutual friend said recently, was that the tether concept was in danger of being overwhelmed by the intellectual inertia of those who thought it was just too farfetched.
That attitude seems strange in light of the fact that NASA was established specifically to take us places we had never been. From its inception, the primary mission of the space program was to develop new ideas and new technologies, even those that might seem impossible.
If Bekey was discouraged, he didn’t show it. In time, his idea became embraced by others. Italy, home to some of the world’s leading physicists, agreed to supply a satellite to test the concept, and in 1992 it flew for the first time aboard the shuttle. But the tiny tether, made of copper, Nomex and Teflon and no wider than a strand of spaghetti, tangled with a safety bolt that had been added to the system shortly before the flight. The tether jammed just 850 feet from the shuttle.
Last month, the satellite was deployed successfully, and it drifted outward from the shuttle to the tether’s full length of 12.5 miles. As the satellite swept through the Earth’s magnetic field lines at 5 miles per second, electrons began flowing down the tether, proving Bekey had been right.
The experiment was to have lasted 48 hours, but for unknown reasons the tether suddenly snapped and the satellite drifted away. It had produced 3,000 volts--falling short of the goal of 5,000 volts--but it had indeed produced electricity.
Inadvertently, the failure proved another of Bekey’s contentions. He had argued years ago that two objects tethered together in space would drift rapidly apart if the tether was suddenly severed. Bekey felt that held the possibility of boosting the orbit of a spacecraft while jettisoning waste products from the end of a tether.
When the cable snapped, the satellite picked up a boost of about 80 feet per second as it sped away from the Columbia, causing astronaut Jeffrey Hoffman to note the irony of it all.
“Well, we have demonstrated you can generate a lot of electricity with a tether,” Hoffman told Mission Control. “Unfortunately, we’ve also demonstrated that you can use tethers to launch a satellite into a much higher orbit.”
With two mechanical failures on its record, there will be a temptation for image-conscious and money-strapped planners at NASA to conclude that the theory has been verified and that no other experiments are necessary. That would be a pity, because we have just scratched the surface.
Nobie Stone, mission scientist for the tether project, said he believes tethers may provide the solution to one of the most vexing barriers to long-term space travel. It is generally believed that long-endurance flight in zero gravity is not practical and that if humans are ever to reach Mars, they must have some form of artificial gravity during their yearlong jaunts.
Stone believes two vehicles tethered together and orbiting around the center of their mass might provide the necessary artificial gravity through centrifugal force.
That’s the kind of thinking that landed Ivan Bekey in an office at the end of a long hall. Will we ever learn if Stone is right?
Lee Dye can be reached by e-mail at 72040.3515@compuserve.com
