by Ben Bova
“…if it works,” he was hollering over the rumble of the truck’s groaning engine, “we’ll be able to provide electricity for the whole blinking country. Maybe for Colombia, Peru, parts of Brazil, the whole blasted northwestern bloc of South America!”
“If what works?” she asked.
“Tapping the ionosphere,” he answered. Gesturing with both hands as he spoke, he shouted, “Enormous electrical energy up there, megawatts per cubic meter. At first we were worried that the tower would be like a big lightning rod, conducting down to the ground. Zap! Melt the bedrock, maybe.”
“My god,” Lara said.
“But we insulated the outer shell so that’s not a problem.”
Before Lara could think of something to say, Mance went on, “Then I started thinking about how we might tap some of that energy and use it to power the elevators.”
“Tap the ionosphere?”
“Right. It’s replenished by the solar wind. Earth’s magnetic field traps solar protons and electrons.”
“That’s what causes the northern lights,” Lara said, straining to raise her voice above the laboring diesel’s growl.
“Yep. If we work it right, we can generate enough electricity to run the blinking tower and still have enough to sell to users on the ground. We can recoup all the costs of construction by selling electrical power!”
“How much electricity can you generate?” she asked.
“What?” he yelled.
She repeated her question, louder.
He waggled his right hand. “Theoretically, the numbers are staggering. Lots of gigawatts. I’ve got Mitchell working on it.”
That’s a benefit no one thought about, Lara said to herself. The original idea of the skytower was to build an elevator that could lift people and cargo into space cheaply, for the cost of the electrical energy it takes to carry them. Pennies per pound, instead of the hundreds of dollars per pound that rocket launchings cost. Now Mance is talking about using the tower to generate electricity, as well. How wonderful!
Then a new thought struck her. “Isn’t this earthquake territory?” she shouted into Mance’s ear.
His grin didn’t fade even as much as a millimeter. He nodded vigorously. “You bet. We’ve had two pretty serious tremors already, Riehter sixes. The world’s highest active volcano is only a couple hundred kilometers or so from our site.”
“Isn’t that dangerous?”
“Not for us. That’s one of the reasons we used the banyan tree design. The ground can sway or ripple all it wants to—the tower’s not anchored to the ground, just tethered lightly. It won’t move much.”
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 wa
s 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.”
Bracknell’s face went even redder. But he grinned like a schoolboy. “Well, okay,” he said, hefting her travel bags. “Great.”
Lara had brought only the two bags with her. They were close enough to Quito for her to buy whatever she lacked, she had reasoned.
Bracknell’s apartment was small, utilitarian, and so gleamingly neat that she knew he had cleaned it for her. Through the screened windows she could see the streets of the little city and, beyond them, the green-clad mountains. The skytower was not in view from here.
“No air conditioning?” she asked as he plopped her bags onto the double-sized bed.
“Don’t need it. Climate’s very mild; it’s always springtime here.”
“But we’re on the equator, aren’t we?”
“And nearly four kilometers high.”
She nodded. Like Santa Fe, she thought. Even Denver had a much milder climate than most people realized.
As she opened the larger of her two bags, Lara asked, “So the weather’s not a problem for the skytower?”
“Even the rainy season isn’t all that bad. That’s one of the reasons we picked this site,” Bracknell said as he peered into the waist-high refrigerator in his kitchen alcove. He pulled out an odd-shaped bottle. “Some wine? I’ve got this local stuff that’s pretty bad, and a decent bottle of Chilean—”
“Just cold water, Mance,” she said. “We can celebrate later.”
He nearly dropped the bottle he was holding.
Bracknell had a surprise for her at dinner: Victor Molina, whom they had both known at university.
“I had no idea you were part of this project,” Lara said, as they sat at a small square table in the corner of the city’s only restaurant. A quartet of musicians was tuning up across the way. Lara noticed that their amplifiers were no bigger than tissue boxes, not the man-tall monsters that could collapse your lungs when they were amped up full blast.
The restaurant was hardly half filled, Lara saw. Either most of the people eat at home or they come in much later than this, she reasoned. It was a bright, clean little establishment. No tablecloths, but someone had painted cheerful outdoor scenes of jungle greenery and colorful birds on the tabletops.
“Victor’s the reason we’re moving ahead so rapidly,” Bracknell said.
Lara refocused her attention on the two men. “I thought you were into biology back at school,” she said.
“I still am,” Molina replied, his striking blue eyes fastened on her. He was as good-looking as ever, she thought, in an intense, urgent way. Lara remembered how, at school, Molina had pursued the best-looking women on campus. She had dated him a few times, until she met Mance. Then she stopped dating anyone else.
Before she could ask another question, the robot waiter rolled up to their table. Its flat top was a display screen that showed the evening’s menu and wine list.
“May I bring you a cocktail before you order dinner?” the robot asked, in a mellow baritone voice that bore just a hint of an upper-class British accent. “I am programmed for voice recognition. Simply state the cocktail of your choice in a clear tone.”
Lara asked for sparkling water and Bracknell did the same. Molina said, “Dry vodka martini, please.”
“Olives or a twist?” she asked the robot.
“Twist.”
The little machine pivoted neatly and rolled off toward the service bar by the kitchen.
Lara leaned slightly toward Molina. “I still don’t understand what a biologist is doing on this skytower project.”
Before Molina could reply, Bracknell answered, “Victor’s our secret weapon. He’s the one who’s allowed us to move ahead so rapidly.”
“A biologist?”
Molina’s eyes were still riveted on her. “You’ve heard of nanotechnology, haven’t you?”
“Yes. It’s banned, forbidden.”
“True enough,” he said. “But do you realize there’s nanotechnology going on inside your body at this very instant?”
“Nanotech?”
“Inside the cells of your body. The ribosomes in your cells are building proteins. And what are they other than tiny little nanomachines?”
“Oh. But that’s natural.”
“Sure it is. So is the way we build buckyball fibers.”
“With nanomachines?”
“Natural nanomachines,” Bracknell said, trying to get back into the conversation. “Viruses.”
The robot brought their drinks and, later, they selected their dinner choices from the machine’s touch screen. Molina and Bracknell explained how Molina had used genetically engineered viruses to produce buckyball molecules and engineered microbial cells to put the buckyballs together into nanotubes.
“Once we have sets of nanotubes,” Molina explained, “I turn them over to the regular engineers, and they string them together into the fibers that make up the tower.”
“And you’re allowed to do this in spite of the ban on nanotechnology?” Lara asked.
“There’s nothing illegal about it,” Molina said lightly.
“But we’re not shouting the news from the rooftops,” Bracknell added. “We want to keep this strictly under wraps.”
“It’s a new construction technique that’ll be worth billions,” Molina said, his eyes glowing. “Trillions!”
“Once we get it patented,” Bracknell added.
Lara nodded, absently taking a forkful of salad and chewing contemplatively. Natural nanotechnology, she thought. Genetically engineered viruses. There are a lot of people who’re going to get very upset when they hear about this.
“I can see why you want to keep it under wraps,” she said.
Publish Or Perish
“What I really want,” Molina was saying, “is to get into astrobiology.”
“Really?” Lara felt surprised. In all the weeks she had been at Ciudad de Cielo, this was the first time he’d broached the subject with her.
<
br /> She was walking with the biologist along the base city’s main street, wearing a colorful wool poncho that she’d bought from one of the street vendors that Mance allowed into town on the weekends. The wind off the mountains was cool, and it had drizzled for a half hour earlier in the morning. The thick wool poncho was just the right weight for this high-altitude weather. Molina had pulled a worn old leather jacket over his shirt and jeans.
“Astrobiology’s the hot area in biology,” he said. “That’s where a man can make a name for himself.”
“But you’re doing such marvelous things here.”
He looked over his shoulder at the skytower looming over them. Gray clouds scudded past it. With a discontented shrug, Molina said, “What I’m doing here is done. I’ve trained some bugs to make buckyball fibers for Mance. Big deal. I can’t publish my work; he’s keeping the whole process secret.”
“Only until the patent comes through.”
Molina frowned at her. “Do you have any idea of how long it takes to get an international patent? Years! And then the Skytower Corporation’ll probably want to keep the process to themselves. I could waste the best years of my career sitting around here and getting no credit for my work.”
Lara saw the impatience in his face, in his rigidly clenched fists, as they walked down the street. “So what do you intend to do?”
Molina hesitated for a heartbeat, then replied, “I’ve sent an application to several of the top astrobiology schools. It looks like Melbourne will accept me.”
“Australia?”
“Yes. They’ve just gotten a grant to search for more Martian ruins and they’re looking for people.”