Lara realized she looked unconvinced because Mance added, “Besides, we’re not on a fault line. Nowhere near one. I got solid geological data before picking the site. The ground’s not going to open up beneath us, and even if it did the tower would just stand there, solid as the Rock of Gibralter.”
“But if it should fall … all that weight…”
Mance’s smile turned almost smug. “It won’t fall, honey. It can’t. The laws of physics are on our side.”
DATA BANK
Skyhook.Beanstalk. Space elevator. Skytower. All these names and more have been applied to the idea of building an elevator that can carry people and cargo from the Earth’s surface into orbital space.
Like many other basic concepts for space transportation, the idea of a skytower originated in the fertile mind of Konstantin Tsiolkovsky, the Russian pioneer who theorized about rocketry and astronautics in relative obscurity around the turn of the twentieth century. His idea for a “celestial castle” that could rise from the equator into orbital space, published in 1895, may have been inspired by the newly built Eiffel Tower, in Paris.
In 1960, the Russian engineer Yuri Artsutanov revived the concept of the space elevator. Six years later an American oceanographer, John Isaacs, became the first outside of Russia to write about the idea. In 1975, Jerome Pearson, of the U.S. Air Force Research Laboratory, brought the space elevator concept to the attention of the world’s scientific community through a more detailed technical paper. The British author Arthur C. Clarke popularized the skyhook notion in several of his science fiction novels.
Although it sounds outlandish, the basic concept of a space elevator is well within the realm of physical possibility. As Clarke himself originally pointed out, a satellite in geostationary orbit, slightly more than thirty-five thousand kilometers above the equator, circles the Earth in precisely the same time it takes for the Earth to revolve about its axis. Thus such a satellite remains constantly above the same spot on the equator. Communications satellites are placed in geostationary Clarke orbits so that ground-based antennas may be permanently locked onto them.
To build a skytower, start at geostationary orbit. Drop a line down to the Earth’s surface and unreel another line in the opposite direction, another thirty-five thousand kilometers into space. Simple tension will keep both lines in place. Make the line strong enough to carry freight and passenger elevators. Voila! A skyhook. A beanstalk. A skytower.
However, in the real world of practical engineering, the skytower concept lacked a suitable construction material. All known materials strong enough to serve were too heavy for the job. The tower would collapse of its own weight. A material with a much better strength-to-weight ratio was needed.
Buckyball fibers were the answer. Buckminsterfullerene is a molecule of sixty carbon atoms arranged in a sphere that reminded the chemists who first produced them of a geodesic dome, the type invented by the American designer R. Buckminster Fuller. Quickly dubbed buckyballs, it was found that fibers built of such molecules had the strength-to-weight ratio needed for a practical space elevator—with a considerable margin of error to spare. Where materials such as graphite, alumina, and quartz offer tensile strengths in the order of twenty gigapascals (a unit of measurement for tensile strength) the requirements for a space elevator are more than sixty gigapascals. Buckyball fibers have tensile strengths of more than one hundred gigapascals.
By the middle of the twenty-first century all the basic technical demands of a skytower could be met. What was needed was the capital and the engineering skill to build such a structure: a tower that rises more than seventy thousand kilometers from the equator, an elevator that can carry payloads into space for the price of the electricity used to lift them.
Backed by the nation of Ecuador and an international consortium of financiers, Skytower Corporation hired Mance Bracknell to head the engineering team that built the skytower a scant hundred kilometers from Quito. People in the streets of the Ecuadorian capital could see the tower rising to the heavens, growing thicker and stronger before their eyes.
Many glowed with pride as the tower project moved toward completion. Some shook their heads, however, speaking in worried whispers about the biblical Tower of Babel. Even in the university, philosophers spoke of man’s hubris while engineers discussed moduli of elasticity. In Quito’s high-rise business towers, men and women who dealt in international trade looked forward to the quantum leap that the tower would produce for the Ecuadorian economy. They saw their futures rising as high as the sky, and quietly began buying real estate rights to all the land between Quito and the base of the tower.
None of them realized that the skytower would be turned into a killing machine.
CIUDAD DE CIELO
“It’s huge,” Lara said, as she stepped down from the Humvee. Inwardly she thought of all the phallic jokes the men must be making about this immense tower.
“A hundred meters across at the base,” Bracknell said, heading for the back of the truck where her luggage was stored. “The size of a football field.”
The driver stayed behind his wheel, anxious to get his pay and head back to the airport.
“It tapers outward slightly as it rises,” Bracknell went on. “The station up at geosynch is a little more than a kilometer across.”
The numbers were becoming meaningless to her. Everything was so huge. This close, she could see that each of the interwound cables making up the thick column must be a good five meters in diameter. And there were cables angling off to the sides, like the roots of a banyan, except that there were buildings where the cables reached the ground. They must be the tethers that Mance told me about, Lara thought.
“Well,” he said, grinning proudly as he spread his arms, “this is it. Sky City. Ciudad de Cielo.”
It was hard to take her eyes off the skytower, but Lara made the effort and looked around her. At Mance’s instruction, the taxi had parked in front of a two-story building constructed of corrugated metal walls. It reminded her of an airplane hangar or an oversized work shed. Looking around, she saw rows of such buildings laid out along straight paved streets, a neat gridwork of almost identical structures, a prefabricated little city. Sky City. It was busy, she saw. Trucks and minivans bustled about the streets, men and women strode purposively along the concrete sidewalks. Very little noise, though, she realized. None of the banging and thumping that usually accompanied construction projects. Of course, Lara thought: all the vehicles are powered by electrical engines. This city was quietly intense, humming with energy and purpose.
Then she smiled. Somewhere down one of those streets someone was playing a guitar. Or perhaps it was a recording. A softly lyrical native folk song, she guessed. Its gentle notes drifted through the air almost languidly.
Bracknell pointed. “The music’s coming from the restaurant. Some of our people have formed groups; they entertain in the evenings. Must be rehearsing now.”
He picked up both her travel bags and led her from the parking lot up along the sidewalk toward the building’s entrance.
“This is where my office is. And my living quarters, up on the second floor.” He hesitated, his tanned face flushing slightly. “Uh, I could set you up in a separate apartment if you want…”
Both his hands were full with her luggage, so she stepped to him and wrapped her arms around his neck and kissed him soundly. “I didn’t come all this way to sleep alone.”