“That’s just the sort of argument people made when the Space Age started. Now look where we are! Men and women will go to Jupiter because—er, because it’s there. But if you don’t like Jupiter—how about Saturn? Almost the same gravity as Earth—and just think of the view! Cruising in high latitudes, where you can see the rings—one day that will be a major tourist attraction.”
“Cheaper to plug into a Brainman. All the fun and none of the risk.”
Fletcher laughed as Singh quoted the famous slogan.
“You don’t believe that, of course.”
He was right, but Singh had no intention of admitting it. The element of risk was what distinguished Reality from its imitations, however perfect. And the willingness to take risks—indeed, to welcome them, if they were reasonable—was what gave zest to life and made it worthwhile.
Another of the Europa-bound passengers was involved with a technology that seemed even more out of place than aeronautics—that of deep-diving submersibles. In all the Solar System, Europa was the only world apart from Earth that possessed oceans, sealed beneath a crust of ice that protected them from space. The heat produced by Jupiter’s immense gravitational tides—the same forces that triggered the volcanoes of neighboring Io—kept the global ocean from freezing.
Where there was liquid water, there was hope of life. Dr. Rani Wijeratne had spent twenty years exploring the Europan abyss, both in person and by means of robot probes. Though she had found nothing, she was not discouraged.
“I’m sure it’s there,” she said. “I only hope I can find it before some Earth-based microbes crawl out of our garbage and take over.”
Dr. Wijeratne was also quite optimistic about the prospects for life much farther from the sun—in the great cloud of comets far beyond Neptune.
“There’s all the water and carbon and nitrogen and other chemicals out there,” she was fond of saying. “Millions of times as much as on the planets. And there must be radioactivity—which means heat, and a rapid mutation rate. Conditions may be ideal for the origin of life, deep down inside comets.”
It seemed a pity that the doctor would be disembarking at Europa, and not continuing on to Kali. Her good-natured but no-holds-barred debates with Sir Colin Draker, FRS, had provided the other passengers with a great deal of entertainment. The famous astrogeologist was the only scientist still aboard from Goliath’s original complement, being sufficiently eminent to overrule any orders to bring him home.
“I know more about asteroids than any living man,” he argued with unchallengeable accuracy. “And Kali is the most important asteroid in history. I want to get my hands on it—as my one-hundredth birthday present to myself. And for the sake of science, of course.”
As for the cometary life-forms suggested by Dr. Wijeratne, he had no doubts.
“Nonsense! Hoyle and Wickremasinghe suggested that over a century ago, but no one ever took it seriously.”
“Then it’s time they did. And since asteroids—some of them, anyway—are dead comets, have you ever looked for fossils? It might be worth doing.”
“Frankly, Rani, I can think of much better ways of spending my time.”
“You geologists! Sometimes I think you’re all fossils yourselves! Remember how you laughed at poor Wegener and his theory of continental drift—and made him your patron saint when he was safely dead?”
And so forth—all the way to Europa.
Europa, the smallest of Jupiter’s four Galilean satellites, was the only world in the Solar System that could be mistaken for Earth—if you were close enough. As Captain Singh looked down on the endless expanse of ice floes beneath him, it was easy to imagine that he was really orbiting the home planet.
That illusion vanished quickly when he turned his eyes toward Jupiter. Racing through its phases every three and a half days, the giant world dominated the sky, even when it had dwindled to a vanishingly thin crescent. For then that arc of light cradled a huge black disk twenty times the diameter of the Moon in Earth’s sky—blotting out the stars and presently eclipsing the distant sun. And the night side of Jupiter was seldom completely dark; thunderstorms larger than terrestrial continents flickered back and forth, like an exchange of nuclear weapons—and with equal energy. Rings of auroral light usually draped the poles, and geysers of phosphorescence welled up from the planet’s unexplored—perhaps forever unexplorable—depths.
And when it was near full, the planet was even more impressive. Then the intricate loops and curlicues of the cloud belts, eternally marching parallel to the Equator, could be seen in their multicolored glory. Along them moved pale, oval islands—like thousand-kilometer-wide amoebae; sometimes they appeared to thrust so purposefully through the cloudscape around them that it was easy to believe they were enormous living creatures. More than one fanciful astro-epic had been based on just this hypothesis.
But the show-stealer was the Great Red Spot. Though it had waxed and waned over the centuries, sometimes disappearing almost completely, it was now more prominent than it had ever been since Cassini had discovered it in 1665. As Jupiter’s dizzying ten-hour rotation swept it across the face of the planet, it looked as if a giant bloodshot eye were staring malevolently out into space.
It was no wonder that workers on Europa had the shortest tour of duty, and the highest rate of mental breakdown, of any planet-based staff. Matters had improved somewhat when facilities had been moved to the center of Farside, where Jupiter was perpetually hidden. Yet even here the psychologists reported that some patients believed that unblinking, Cyclopean eye was watching them through three thousand kilometers of solid rock….
Watching them, perhaps, as they stole Europa’s treasure. The satellite was the only major source of water—and hence hydrogen—within the orbit of Saturn. Although there were even greater amounts in the comet clouds far beyond Pluto, it was not yet economical to mine them. One day, perhaps… meanwhile Europa supplied most of the propellant for the commerce of the Solar System.
Moreover, Europan hydrogen was superior to that from Earth. Thanks to eons of bombardment from the radiation fields around Jupiter, it contained a much higher percentage of the heavier isotope deuterium. With only a little more enrichment it supplied the optimum mixture needed to power a fusion drive. Occasionally—not often—Nature cooperated with Mankind.
Already it was difficult to remember life before Kali. The moment of peril was still months away, but almost every thought and action was focused upon it. And to think, Robert Singh sometimes reminded himself ironically, that I took this job because I wanted an undemanding assignment before I retired with the rank of full captain!
It was not often that he had time for such introspection, for the once-regular ship’s routine had now been superseded by what his first officer had called “planned crises.” And yet, in view of the complexity of Operation ATLAS, everything had gone with reasonable smoothness; there had been no major holdups, and the program was only two days behind what had once seemed to be an impossible schedule.
Once Goliath/ATLAS had been established in parking orbit, the lengthy process of filling their tanks with two hundred thousand tons of hydrogen-deuterium slush, at thirteen degrees above absolute zero, began in earnest. The Europan electrolysis plants could produce this amount in a week, but getting it up to orbit was another matter. By bad luck, two of Europa’s tankers were undergoing major repairs, which could not be handled locally. They had been towed back to Deimos….
And so, even if everything went smoothly, it would take almost a month to fill the cavernous tanks. During that time, Kali would come a hundred million kilometers closer to Earth.
PART V
26
MASS DRIVER
VERY LITTLE OF THE ORIGINAL GOLIATH WAS NOW VISIBLE: THE whole of one side was concealed beneath the tanks and propulsion modules of ATLAS, a compact mass of plumbing almost two hundred meters long. Most of the remainder of the ship was also hidden by its own additional tankage. We won’t have much of a view, Sin
gh told himself, until we’ve dropped off some of our empties. Or much acceleration either, despite the engine upgrades, with all that extra mass.
It was difficult to believe that the future of humanity might well depend on this ungainly collection of hardware. It had been designed and assembled with one single objective in mind—to land a powerful mass driver on Kali as quickly as possible. Goliath was merely the delivery van, the interplanetary space-truck: ATLAS was the all-important cargo, which had to reach its destination on time, and in good condition.
Achieving this objective involved an extraordinary number of trade-offs. Although it was essential to reach Kali with minimum delay, speed could be bought only at the expense of payload. If Goliath burned up too much hydrogen getting to Kali, there might not be enough left to divert the asteroid from its baleful trajectory, and the whole effort would have been in vain.
To shorten mission time without using propellant, some thought had been given to the classic “gravity boost” used by the first spacecraft to explore the outer Solar System. Goliath could dive in toward Jupiter and rob the giant planet of some of its momentum as it skimmed past. However, the plan had been reluctantly abandoned because of its risks; there was too much junk orbiting around Jupiter. The tenuous rings extended right down to the limits of the atmosphere, and even the smallest fragment could puncture the lightly constructed hydrogen tanks. It would be the ultimate irony if a tiny Jovian micro-moon frustrated the mission.
Unlike a liftoff from a planetary surface, there was nothing in the least dramatic about the start of an orbital transfer. There was, of course, no sound, and not even a visible indication of the awesome energies involved. The plasma jet driving Goliath was much too hot to emit the feeble radiations that the human eye can detect; it wrote its signature across the stars in the far ultraviolet. To the spectators watching from the Europa satellite complex, the only indication that Goliath had started to move was the small cloud of debris it left behind—fragments of thermal shielding, discarded packing material, pieces of string and tape—all the junk left over on a major construction project by even the most careful workers. It was not the grandest of beginnings, for so noble an enterprise: but Goliath and its ATLAS payload were on their way, carrying the hopes and fears of all mankind.
A day later, accelerating at a tenth of a gravity, Goliath lumbered past the second largest satellite, battered Callisto. But it was almost a week before it finally escaped from Jovian territory, crossing the wildly erratic orbits of the tiny outermost twins Pasiphaë and Sinope. By then it was moving so swiftly that not even the sun could call it back; it would leave the Solar System completely, if it was unable to check its speed again, and begin an endless journey among the stars.
But no spaceship commander could have hoped for a more uneventful voyage. Goliath and ATLAS made their rendezvous with Kali twelve seconds ahead of schedule.
“I’ve visited dozens of asteroids,” said Sir Colin Draker to his unseen audience half a billion kilometers sunward, “and even now, there’s no way I can judge their size merely by looking at them. I know exactly how big Kali is, but I could easily fool myself into thinking I could hold it between my outstretched arms.
“The problem is, there’s absolutely no sense of scale—nothing to give any clue to the eye. As you’ll see, it’s covered with shallow impact craters right down to the limit of vision. That big one, left center, is actually about fifty meters across—but it looks exactly like the little ones all around it—the smallest you can see are a few centimeters across.
“Will you zoom in, David? Thanks—now, we’re getting closer—but there’s no real difference in the picture. The mini-craters we’re seeing now look just like their big brothers—stop the zoom there, David—even if we used a magnifying glass, the image would look much the same—shallow craters of every possible size—right down to ones made by dust particles.
“Now pull back to show the whole of Kali again—thanks. You’ll see that there’s virtually no color, at least to the human eye. It’s almost black—you might guess it was a lump of coal, and you wouldn’t be far wrong—the outer layers are ninety percent carbon.
“Inside, though, it’s different—iron, nickel, silicates, various ices—water, methane, carbon dioxide. It’s obviously had a very complicated history, and in fact I’m almost certain it’s an aggregate of two bodies of quite different composition that collided fairly gently and then stuck together.
“You may have noticed that some new craters have come into view while I’ve been talking. Kali’s day is quite short—three hours twenty-five minutes. And the fact that it’s rotating makes our job even trickier….
“Can we have the other side, David? Center on Grid Reference K5—that’s it….
“Notice the change of scenery—if you can call it that. Those grooves must have been caused by another collision—this time quite a violent one. Kali must have been in a busy part of the Solar System, ten billion years ago. See that valley top right—we’ve christened it the Grand Canyon. It’s all of ten meters deep, but if you didn’t know the scale, you easily could imagine you were in Colorado….
“So—we have a battered little world—shaped like a dumbbell, or a peanut—with a mass of two billion tons. And by bad luck, it’s moving in a retrograde orbit—that is, in the opposite direction to all the planets. Nothing very unusual about that—Halley does just the same—but it means that it will collide with the Earth head-on—the worst possible case, of course. So we’ve got to divert it. If we don’t, then not only our civilization, but even our species, may be wiped off the face of the planet.
“The ATLAS mass driver has now been detached from Goliath—pan to ATLAS please, David—and we’re now engaged in the delicate job of installing it on Kali. Fortunately, the asteroid’s gravity is so feeble—about one ten-thousandth of Earth’s—that ATLAS weighs only a few tons. Don’t let that fool you though. It still has all its mass—and its momentum. So it has to be moved very, very slowly and carefully…. Believe it or not, the main tools for the job are old-fashioned winches and pulleys, anchored on Kali.
“In a few hours, ATLAS will be ready to start firing. Of course, its effect on Kali will be almost too small to measure—a fraction of a microgravity. I believe some media person said it would be like a mouse pushing an elephant: true enough. But ATLAS can keep pushing for days, and we have to move Kali only a few centimeters, out here around Jupiter, for it to miss Earth by thousands of kilometers.
“And even a hundred would be as good as a light-year.”
27
DRESS REHEARSAL
A BALD SIKH! HOW WOULD MY HIRSUTE ANCESTORS, BACK there in India, have reacted to such an apostate? And if they knew that I’d had my scalp permanently depilated—well, I’d be lucky to escape alive….
This thought invariably flashed through Robert Singh’s mind when he lowered the tightly fitting skullcap over his head, adjusted the restraining straps, and checked that the eye pads were excluding all light. Then he sat in total darkness and silence, waiting for the automatic sequencer to take over.
First there was the faintest of sounds, so low-pitched that he could almost hear the separate vibrations. Still at the limit of detectability, it climbed upward octave by octave until it vanished at the edge of hearing. Indeed, beyond that, for though Singh had never bothered to check, he was quite sure that the mechanism of his ears could never respond to the frequencies that were now flowing directly into his brain.
Silence returned, and he waited for the far more complex vision calibration sequence to begin.
First there was pure color: he might have been floating at the center of a perfectly featureless sphere, its inner surface painted the deepest red. There was not the slightest trace of pattern or structure, and the eyes ached in the attempt to find some. No—that was not quite correct. The eyes did not come into the circuit at all.
Red—orange—yellow—green—the familiar colors of the rainbow, but in laser-sharp purity. Still no
image of any kind—only an unbroken chromatic field.
At last, images began to appear. First an open grid, which filled up rapidly with reticulations that became finer and finer, until they could no longer be resolved. This was replaced by a sequence of geometric shapes—rotating, expanding, shrinking, morphing into each other. Though he had lost all sense of time, the whole calibration program had lasted less than a minute. When a soundless “white-out” engulfed him like an Antarctic blizzard, he knew that the scanning process was complete, and that the Brainman’s monitoring system had satisfied itself that his neural circuits were properly matched to receive its outputs.
Sometimes, though very rarely, an “error message” would flash across his field of consciousness, and he would have to repeat the whole sequence. That usually cleared the problem; if it did not, Singh knew better than to try again. Once, when he had needed to acquire some skills in a hurry, he had operated the manual over-ride in an attempt to bypass the electronic roadblock. His reward had been a nightmare display of images, always just beyond his ability to grasp properly—like the phosphenes that result from pressure on the eyeballs, but far more brilliant. By the time he had hit the cut-out, he had acquired a splitting headache—and it could have been much worse. Irreversible “zombification” by malfunctioning Brainmen was no longer as common as in the early days of the device, but it still happened.
This time there was no error message or other warning signal. All circuits were clear. He was ready to receive.
Though some remote corner of his mind knew that he was really aboard Goliath, it did not appear the least incongruous to Captain Singh to be looking down upon his ship as it floated alongside Kali. It also seemed quite logical—even if it was the bizarre logic of a dream—that ATLAS was already installed on the asteroid, even though he “knew” that it was really still attached to Goliath.
The Hammer of God Page 10
