The Last Theorem

37 THE RACE

Her ship’s name was Diana, chosen by Natasha Subramanian herself. It had never flown. Now it was ready. It lay moored to its mother ship with its enormous disk of sail straining at the rigging, already filled with the great, silent wind that blew between the worlds. The race was ready to begin.

“T minus two minutes,” said her cabin radio. “Cross-check to confirm readiness.”

One by one the other skippers answered. Natasha recognized every voice—some tense, some almost inhumanly calm—for they were the voices of her friends and rivals. In all of the places where humanity dwelt there were scarcely a score of men and women who owned the skills needed to sail a sun yacht. Every one of them was here, at the starting line like Natasha or aboard the escort vessels, orbiting thirty-six thousand kilometers above Earth’s equator.

“Number One, Gossamer. Ready to go!”

“Number Two, Woomera, all okay.”

“Number Three, Sunbeam. Okay!”

“Number Four, Santa Maria, all systems go.” Natasha smiled. That one was Ron Olsos, of course, whom she liked, though perhaps not as much as he seemed to like her. The Brazilian’s reply had been an ancient echo from the early days of astronautics, typical of Ron’s tendency toward the theatrical.

“Number Five, Lebedev. We’re ready.” That was the Russian, Efremy.

“Number Six, Arachne. Also okay.” Hsi Liang, the young woman from some village north of Chengdu, in the shadow of the Himalayas. And then, at the end of the line, it was Natasha’s turn to say the words that would be heard around the world and in every human outpost:

“Number Seven, Diana. Ready to win!”

And let old Ronaldinho take that, she thought as she turned to make one last check of the tensions in her rigging.

To Natasha, floating weightless in her tiny cabin, Diana’s sail seemed to fill the sky. Well it might. Out there, ready to take her free of Earth’s gravitational bonds, were more than five million square meters of sail, webbed to her command capsule by almost a hundred kilometers of bucky-cord rigging. Those square kilometers of aluminized plastic sail, though only a few millionths of a centimeter thick, would exert enough force—she hoped!—to put her first across the lunar-orbit finish line.

The wall speaker again: “T minus ten seconds. All recording instruments on!”

Eyes still fixed on the vast billow of sail, Natasha touched the switch that turned on all Diana’s cameras and instrument recorders. It was the sail that held her imagination. Something that was at once so huge and so frail was difficult for the mind to grasp. Harder still was to believe that this mirrored wisp could tow her ever faster through space by nothing more than the power of the sunlight it would trap.

“…five, four, three, two, one. Detach!”

Seven diamond-edged computer-controlled knife blades sliced through seven thin tethers at once. Then the yachts were free. Until this moment yachts and servicing vessels had circled the Earth as a single unit, firmly held together. Now the yachts would begin to disperse like dandelion seeds drifting before a breeze.

And the one that first drifted past the orbit of the moon would be the winner.

Aboard Diana nothing among the senses of Natasha’s body registered a change. She had not expected anything would; the only thing that showed that any thrust at all was being exerted was the dial on her instrument board, now registering an acceleration that was almost one one-thousandth of one Earth gravity.

That was, of course, almost ludicrously tiny. Yet it was more than any manned solar-sail vessel had ever managed before, just as Diana’s designers and builders had promised it would be. Such accelerations had never been achieved in any but toy-size rigs, but there it was now. At this rate—she calculated quickly, smiled as the result appeared on her board—she would need only two circuits of Earth to build up enough velocity to leave low earth orbit and head for the moon. And then the full force of the sun’s radiation would be behind her.

The full force of the sun’s radiation…

Natasha’s smile persisted as she thought of all the attempts she had made to explain solar sailing to audiences of potential backers and the merely curious on Earth. “Hold your hand to the sun, palm up,” she would tell them. “What do you feel?” And then, when there was no answer beyond, perhaps, “a little heat,” she would spring the rationale for solar sailing on them. “But there is something else. There’s pressure. Not much of it, no. In fact so little that you can’t possibly feel it, far less than a milligram’s thrust on your palms. But see what that tiny pressure can do!”

And then she would pull out a few square meters of sail material and toss it toward her audience. The silvery film would coil and twist like smoke, and then drift toward the ceiling on the rising plume of warm air the human bodies made. And Natasha would continue:

“You can see how light the sail is. The whole square kilometer my yacht will deploy weighs less than a ton. That’s all we need. It’s enough to collect two kilograms of radiation pressure, so the sail will start to move…and the rigging will pull my Diana right along with it. Of course, the acceleration will be tiny—less than a thousandth of a G—but let’s see what that pitiful little thrust can do.

“In the first second, Diana will move about half a centimeter. Not even that much, really, because the rigging will stretch enough so that that first move can’t even be measured.”

She would turn toward the screen on the wall of the room, snapping her fingers to set it alight. It would display the vast, if almost impalpable, semi-cylindrical span of the sail, then zoom down to the passenger capsule—not much bigger than a motel shower stall—that would be Natasha’s home for the weeks in transit.

She would then go on. “After a minute, though, the motion is quite detectable. By then we’ve covered twenty meters, and our velocity has become nearly one kilometer per hour…with only a few hundred thousand more kilometers to go to reach the orbit of the moon.”

Then there would often be a faint titter from the audience. Natasha would smile back good-naturedly until it had died away, before going on. “That’s not bad, you know. After the first hour we’ll be sixty kilometers from our starting point, and by then we’ll be moving at a hundred kilometers an hour. And please remember where we are! All of this will be taking place in space, where there is no friction. Once you start something to move, it will move forever, with nothing slowing it down but the gravity of distant objects. You’ll be surprised when I tell you what kind of velocity our thousandth-of-a-G sailboat will be giving us by the end of its first day’s run. Almost three thousand kilometers an hour, all from the thrust of a sunlight pressure that you can’t even feel!”

Well, she’d convinced them. In the end the whole world had been convinced, or at least the people in high places, the decision makers, had been. Foundations, individuals, the treasuries of three great nations (and smaller amounts from dozens of smaller treasuries) had come together to meet the staggering bills for this event. It was paying off, though. The free-flying race in that old lunar lava tube had successfully sparked a trickle of actual lunar tourism. Now this new event already owned the biggest audience in history. And the big boys were already commissioning their prospector vessels, many of them solar-sail-driven themselves, to begin to investigate the raw material wealth of the solar system.

And here was young Natasha de Soyza Subramanian, right in the middle of it all!

Diana had made a good start. Now Natasha had time to take a look at the opposition. For starters she shrugged out of most of her clothing, since there was no one else around to see. Then, moving very cautiously—there were shock absorbers between her control capsule and the delicate rigging of the sail, but Natasha was determined to take no risks at all—she stationed herself at the periscope.

There the other spacecraft were, looking like strange silvery flowers planted in the dark fields of space. There was South America’s Santa Maria, Ron Olsos at the helm, only eighty kilometers away. Santa Maria bore a close resemblance to a boy’s kite, though a kite that measured more than a kilometer on a side. Beyond Santa Maria was the Russian Cosmo-dyne Corporation’s Lebedev, looking like a Maltese cross; the theory, Natasha knew, was that the sails that formed its four fat arms could be used for steering purposes. In contrast, the Australian Woomera was a simple old-fashioned round parachute, though one that was five kilometers in circumference. General Spacecraft’s Arachne, as its name suggested, looked like a spider’s web—and had been built on the same principles, by robot shuttles spiraling out from a central point. Eurospace’s Gossamer was an identical design, though slightly smaller. And the People’s Republic of China’s Sunbeam was a flat ring, with a kilometer-wide hole in the center, spinning slowly so that it was stiffened by centrifugal force. That was an old idea, Natasha knew, but no one had ever made it work well. She was fairly sure the Asian vessel would have trouble when Sunbeam started to turn.

That, of course, would not be for another six hours, after all seven of the solar yachts had moved through the first quarter of their twenty-four-hour geosynchronous orbit. Here, at the beginning of the race, they were all headed directly away from the sun—running, as it were, before the solar wind. Each of them had to make the most of that first lap, before the laws of orbital motion swung them around Earth. When that point was reached, they would suddenly be heading directly back toward the sun. That was when expert pilotage would really count.

Not now, though. Now Natasha had no navigational worries. With the periscope she made a careful examination of her sail, checking each attachment point for the rigging. The shroud lines, narrow bands of unsilvered plastic film, would have been quite invisible had they not been coated with fluorescent dye. Now, in Natasha’s periscope, they were taut lines of colored light, dwindling away for hundreds of meters toward the gigantic span of the sail. Each line had its own little electric windlass, not much bigger than the reel on a fly fisherman’s rod. The windlasses, computer-controlled, were constantly turning, playing lines in or out as the autopilot kept the sail trimmed to the correct angle to the sun.

To Natasha, the play of sunlight on her great mirrored sail was beautiful to watch. The sail undulated in stately oscillations, sending multiple images of the sun marching across it until they faded at the edges. Those oscillations, of course, were not a problem. Such leisurely vibrations were inevitable in so vast and flimsy a structure, and usually quite harmless. Nevertheless, Natasha watched them carefully, alert for signs that they might ultimately build up to the catastrophic waves that were known as “wriggles.” Those could tear a sail to pieces, but her computer reassured her that the present pattern posed no danger.

When she was satisfied that everything was shipshape—and not before!—she allowed herself to access her personal screen. Since everything passed through the command craft before it got to her, and they were careful to pass on only messages from an approved list, she was spared the endless flood of good luck wishes and begging pleas for some favor or other. There was one message from her family, one from Gamini, and one from Joris Vorhulst. No more. She was glad to get them. None required any answer.

Natasha thought for a moment of going to sleep. Of course, the race had just started, but sleeping was something she needed to ration adequately to herself. All the other yachts had two-person crews. They could take turns asleep, but Natasha Subramanian had no one to relieve her.

That had been her own decision, of course—remembering that other solitary sailer, Joshua Slocum, who long ago had single-handedly taken his tiny sailboat, Spray, around the world. If Slocum could do it, she maintained, she could. There was a good reason to try it, too. The performance of a sun yacht depended inversely on the mass it had to move. A second person, with all her supplies, would have meant adding another three hundred kilos, and that could easily have been the difference between winning and losing.

So Natasha snapped the elastic bands of the cabin seat around her waist and legs. She hesitated for a moment. It might be interesting, she thought, to look in on some of the news broadcasts, particularly to see if any astronomer had yet made any sense of that peculiar not-a-supernova that had blossomed astonishingly bright in the southern sky and then simply disappeared….

Discipline won out over curiosity. She placed the electrodes of the sleep-inducer onto her forehead, set the time for three hours, and relaxed. Very gently, the hypnotic pulses throbbed in the frontal lobes of her brain. Colored spirals of light expanded beneath her closed eyelids, widening outward to infinity.

Then nothing.

What dragged Natasha back from her dreamless sleep was the brazen clamor of the alarm. Instantly she was awake, her eyes scanning the instrument board. Only two hours had passed… but above the accelerometer a red light was flashing.

Thrust was failing. The Diana was losing power.

Training brought discipline. Discipline prevented panic. Nevertheless, Natasha’s heart was in her mouth as she cast off her restraining straps to act. Her first thought was that something had happened to the sail. Perhaps the anti-spin devices had failed and the rigging was twisting itself up. But as she checked the meters that read out the tensions of the shroud lines, what they told her was strange. On one side of the sail the meters were reading normally. On the other the value was dropping slowly before her eyes.

Then understanding came. Natasha grabbed the periscope for a wide-angle scan of the edges of the sail. Yes! There was the trouble…and it could have come from only one cause.

The huge sharp-edged shadow that had begun to slide across the gleaming silver of Diana’s sail told the story. Darkness was spreading over one edge of Natasha’s ship as though a cloud had passed between her and the sun, cutting off light, putting a stop to the tiny pressure that drove the craft.

There were no such clouds in space.

Natasha grinned as she swung the periscope sunward. Optical filters clicked automatically into position to save her from instant blindness, and what she saw was precisely what she had expected to see. It looked as though a giant boy’s kite were sliding across the face of the sun.

Natasha recognized the shape at once. Thirty kilometers astern, South America’s Santa Maria was trying to produce an artificial eclipse for Natasha.

“Ha, Senhor Ronaldinho Olsos,” Natasha whispered, “that’s the oldest trick in the book!”

So it was, and a perfectly legal one, too. Back in the days of ocean racing, skippers had done their best to rob opponents of their wind.

But only the incompetents were caught that way, and incompetent, Natasha de Soyza Subramanian was not. Her tiny computer—the size of a matchbook but the equivalent of a thousand human number-crunching experts—considered the problem for a brief fraction of a moment and quickly spat out course corrections.

Two could play at that game. Grinning, Natasha reached out to disable the autopilot and make the adjustments to the trim in her rigging….

That didn’t happen.

The tiny windlasses stayed frozen. Suddenly they were receiving no orders at all, either from the autopilot computer or from the human being that should have been controlling everything.

Solar yacht Diana was no longer under way. The vast sail began to tip….

And then to bend….

And then the ripples in the fabric began to grow into great, irregular billows. And the flimsy material that was the sail reached, and passed, its maximum tolerated stress.

The commodore saw at once that Diana was in trouble. Indeed, the whole fleet did, and radio discipline evaporated in a flash. Ron Olsos was the first to demand a chemical-powered tender to take him off his own ship so that he could help search for Natasha Subramanian in the collapsing ruin that had been the space yacht Diana. He wasn’t the last. Within another hour the race had dissolved into more than a score of vessels of all kinds milling about the crumpled mass that had once been beautiful Diana, doing their best to avoid colliding with one another. The spacecraft that possessed the capability of man-in-space technology suited up as many of their crews as they could and searched.

They searched every fold of the immense crumpled sail—visually when they had to, and with infrared viewers when those were present. These viewers would instantly pick up the tiny signal of a warm human body anywhere in the destroyed sail.

They searched all the space around destroyed Diana, on the chance that somehow Natasha had been flung free through some unknown accident….

Above all, they searched Diana’s tiny cabin.

That didn’t take long. With only herself aboard there was no need for privacy; Diana’s capsule amounted to only a few cubic meters of space, and no possible place to hide.

But she wasn’t there. As far as the searchers could tell, Natasha Subramanian wasn’t anywhere at all.