8
Transit of Jupiter
The image of Jupiter, with its ribbons of white cloud, its mottled bands of salmon pink, and the Great Red Spot staring out like a baleful eye, hung steady on the flight-deck projection screen. It was three-quarters full, but no one was looking at the illuminated disk; all eyes were focused on the crescent of darkness at its edge. There, over the nightside of the planet, the Chinese ship was about to meet its moment of truth.
This is absurd, thought Floyd. We can't possibly see anything across forty million kilometres. And it doesn't matter; the radio will tell us all we want to know.
Tsien had closed down all voice, video, and data circuits two hours before, as the long-range antennas were withdrawn into the protective shadow of the heat shield. Only the omnidirectional beacon was still transmitting, accurately pinpointing the Chinese ship's position as it plunged toward that ocean of continent-sized clouds. The shrill beep... beep... beep... was the only sound in Leonov's control room. Each of those pulses had left Jupiter more than two minutes earlier; by this time, their source might already be a cloud of incandescent gas, dispersing in the Jovian stratosphere.
The signal was fading, becoming noisy. The beeps were getting distorted; several dropped out completely, then the sequence returned. A plasma sheath was building up around Tsien and soon would cut off all communications until the ship re-emerged. If it ever did.
"Posmotri!" cried Max. "There it is!"
At first Floyd could see nothing. Then, just off the edge of the illuminated disk, he made out a tiny star - gleaming where no star could possibly be, against the darkened face of Jupiter.
It appeared quite motionless, though he knew it must be moving at a hundred kilometres a second. Slowly it grew in brilliance; and then it was no longer a dimensionless point, but was becoming elongated. A man-made comet was streaking across the Jovian night sky, leaving a trail of incandescence thousands of kilometres in length.
One last badly distorted and curiously drawn-out beep sounded from the tracking beacon, then only the meaningless hiss of Jupiter's own radiation, one of those many cosmic voices that had nothing to do with Man or his works.
Tsien was inaudible, but not yet invisible. For they could see that the tiny elongated spark had indeed moved appreciably away from the sunward face of the planet and would soon disappear into the nightside. By then, if all had gone according to plan, Jupiter would have captured the ship, destroying its unwanted velocity. When it emerged from behind the giant world, it would be another Jovian satellite.
The spark flickered out. Tsien had rounded the curve of the planet and was heading over the nightside. There would be nothing to see, or to hear, until it emerged from shadow - if all went well, in just under an hour. It would be a very long hour for the Chinese.
To Chief Scientist Vasili Orlov and communications engineer Sasha Kovalev, the hour went extremely quickly. There was much they could learn from observations of that little star; its times of appearance and disappearance and, above all, the Doppler shift of the radio beacon gave vital information about Tsien's new orbit. Leonov's computers were already digesting the figures, and spitting out projected times of re-emergence based on various assumptions about rates of deceleration in the Jovian atmosphere.
Vasili switched off the computer display, spun around in his chair, loosened his seat belt, and addressed the patiently waiting audience.
"Earliest reappearance is in forty-two minutes. Why don't you spectators go for a walk, so we can concentrate on getting all this into good shape? See you in thirty-five minutes. Shoo! Nu ukhodi!"
Reluctantly, the unwanted bodies left the bridge - but, to Vasili's disgust, everyone was back again in little more than thirty minutes. He was still chiding them for their lack of faith in his calculations when the familiar beep... beep... beep... of Tsien's tracking beacon burst from the loudspeakers.
Vasili looked astonished and mortified, but soon joined in the spontaneous round of applause; Floyd could not see who first started the clapping. Rivals though they might be, they were all astronauts together, as far from home as any men had ever travelled - 'Ambassadors for Mankind', in the noble words of the first UN Space Treaty. Even if they did not want the Chinese to succeed, neither did they wish them to meet disaster.
A large element of self-interest was also involved, Floyd could not help thinking. Now the odds in Leonov's own favour were significantly improved; Tsien had demonstrated that the aerobraking manoeuvre was indeed possible. The data on Jupiter was correct; its atmosphere did not contain unexpected and perhaps fatal surprises.
"Well!" said Tanya. "I suppose we should send them a message of congratulations. But even if we did, they wouldn't acknowledge it."
Some of his colleagues were still making fun of Vasili, who was staring at his computer output in frank disbelief.
"I don't understand it!' he exclaimed. 'They should still be behind Jupiter! Sasha - give me a velocity reading on their beacon!"
Another silent dialogue was held with the computer; then Vasili gave a long, low whistle.
"Something's wrong. They're in a capture orbit, all right - but it won't let them make a rendezvous with Discovery. The orbit they're on now will take them way beyond Io - I'll have more accurate data when we've tracked them for another five minutes."
"Anyway, they must be in a safe orbit," said Tanya. "They can always make corrections later."
"Perhaps. But that could cost them days, even if they have the fuel. Which I doubt."
"So we may still beat them."
"Don't be such an optimist. We're still three weeks from Jupiter. They can make a dozen orbits before we get there, and choose the most favourable one for a rendezvous."
"Again - assuming that they have enough propellant."
"Of course. And that's something we can only make educated guesses about."
All this conversation took place in such rapid and excited Russian that Floyd was left far behind. When Tanya took pity on him and explained that Tsien had overshot and was heading for the outer satellites, his first reaction was: 'Then they may be in serious trouble. What will you do if they appeal for help?"
"You must be making a joke. Can you imagine them doing that? They're much too proud. Anyway, it would be impossible. We can't change our mission profile, as you know perfectly well. Even if we had the fuel..."
"You're right, of course; but it might be difficult to explain that to the ninety-nine per cent of the human race that doesn't understand orbital mechanics. We should start thinking about some of the political complications - it would look bad for all of us if we can't help. Vasili, will you give me their final orbit, as soon as you've worked it out? I'm going down to my cabin to do some homework."
Floyd's cabin, or rather one-third of a cabin, was still partly full of stores, many of them stacked in the curtained bunks that would be occupied by Chandra and Curnow when they emerged from their long slumbers. He had managed to clear a small working space for his personal effects and had been promised the luxury of another whole two cubic metres - just as soon as someone could be spared to help with the furniture removing.
Floyd unlocked his little communications console, set the decryption keys, and called for the information on Tsien that had been transmitted to him from Washington. He wondered if his hosts had had any luck in unscrambling it; the cipher was based on the product of two hundred-digit prime numbers, and the National Security Agency had staked its reputation on the claim that the fastest computer in existence could not crack it before the Big Crunch at the end of the Universe. It was a claim that could never be proved - only disproved.
Once again he stared intently at the excellent photographs of the Chinese ship, taken when it had revealed its true colours and was just about to leave Earth orbit. There were later shots - not so clear, because by then it had been far away from the prying cameras - of the final stage as it hurtled toward Jupiter. Those were the ones that interested him most; even more useful were th
e cutaway drawings and estimates of performance.
Granted the most optimistic assumptions, it was difficult to see what the Chinese hoped to do. They must have burned up at least ninety per cent of their propellant in that mad dash across the Solar System. Unless it was literally a suicide mission - something that could not be ruled out - only a plan involving hibernation and later rescue made any sense. And Intelligence did not believe that Chinese hibernation technology was sufficiently far advanced to make that a viable option.
But Intelligence was frequently wrong, and even more often confused by the avalanche of raw facts it had to evaluate - the 'noise' in its information circuits. It had done a remarkable job on Tsien, considering the shortness of time, but Floyd wished that the material sent to him had been more carefully filtered. Some of it was obvious junk, of no possible connection with the mission.
Nevertheless, when you did not know what you were looking for, it was important to avoid all prejudices and preconceptions; something that at first sight seemed irrelevant, or even nonsensical, might turn out to be a vital clue.
With a sigh, Floyd started once more to skim the five hundred pages of data, keeping his mind as blankly receptive as possible while diagrams, charts, photographs - some so smudgy that they could represent almost anything - news items, lists of delegates to scientific conferences, titles of technical publications, and even commercial documents scrolled swiftly down the high-resolution screen. A very efficient industrial espionage system had obviously been extremely busy; who would have thought that so many Japanese holomemory modules or Swiss gas-flow microcontrollers or German radiation detectors could have been traced to a destination in the dried lake bed of Lop Nor - the first milepost on their way to Jupiter?
Some of the items must have been included by accident; they could not possibly relate to the mission. If the Chinese had placed a secret order for one thousand infrared sensors through a dummy corporation in Singapore, that was only the concern of the military; it seemed highly unlikely that Tsien expected to be chased by heat-seeking missiles. And this one was really funny - specialized surveying and prospecting equipment from Glacier Geophysics, Inc., of Anchorage, Alaska. What lamebrain imagined that a deep-space expedition would have any need - the smile froze on Floyd's lips; he felt the skin crawl on the back of his neck. My God - they wouldn't dare! But they had already dared greatly; and now, at last, everything made sense.
He flashed back to the photos and conjectured plans of the Chinese ship. Yes, it was just conceivable - those flutings at the rear, alongside the drive deflection electrodes, would be about the right size.
Floyd called the bridge. "Vasili." he said, "have you worked out their orbit yet?"
"Yes, I have," the navigator replied, in a curiously subdued voice. Floyd could tell at once that something had turned up. He took a long shot.
"They're making a rendezvous with Europa, aren't they?"
There was an explosive gasp of disbelief from the other end.
"Chyort voz'mi! How did you know?"
"I didn't - I've just guessed it."
"There can't be any mistake - I've checked the figures to six places. The braking manoeuvre worked out exactly as they intended. They're right on course for Europa - it couldn't have happened by chance. They'll be there in seventeen hours."
"And go into orbit."
"Perhaps; it wouldn't take much propellant. But what would be the point?"
"I'll risk another guess. They'll do a quick survey - and then they'll land."
"You're crazy - or do you know something we don't?"
"No - it's just a matter of simple deduction. You're going to start kicking yourself for missing the obvious."
"Okay, Sherlock, why should anyone want to land on Europa? What's there, for heaven's sake?"
Floyd was enjoying his little moment of triumph. Of course, he might still be completely wrong.
"What's on Europa? Only the most valuable substance in the Universe."
He had overdone it; Vasili was no fool, and snatched the answer from his lips.
"Of course - water!"
"Exactly. Billions and billions of tons of it. Enough to fill up the propellant tanks - go cruising around all the satellites, and still have plenty left for the rendezvous with Discovery and the voyage home. I hate to say this, Vasili - but our Chinese friends have outsmarted us again.
"Always assuming, of course, that they can get away with it."
9
The Ice of the Grand Canal
Apart from the jet-black sky, the photo might have been taken almost anywhere in the polar regions of Earth; there was nothing in the least alien about the sea of wrinkled ice that stretched all the way out to the horizon. Only the five spacesuited figures in the foreground proclaimed that the panorama was of another world.
Even now, the secretive Chinese had not released the names of the crew. The anonymous intruders on the frozen Europan icescape were merely the chief scientist, the commander, the navigator, the first engineer, the second engineer. It was also ironic, Floyd could not help thinking, that everyone on Earth had seen the already historic photograph an hour before it reached Leonov, so much closer to the scene. But Tsien's transmissions were relayed on such a tight beam that it was impossible to intercept them; Leonov could receive only its beacon, broadcasting impartially in all directions. Even that was inaudible more than half the time, as Europa's rotation carried it out of sight, or the satellite itself was eclipsed by the monstrous bulk of Jupiter. All the scanty news of the Chinese mission had to be relayed from Earth.
The ship had touched down, after its initial survey, on one of the few islands of solid rock that protruded through the crust of ice covering virtually the entire moon. That ice was flat from pole to pole; there was no weather to carve it into strange shapes, no drifting snow to build up layer upon layer into slowly moving hills. Meteorites might fall upon airless Europa, but never a flake of snow. The only forces moulding its surface were the steady tug of gravity, reducing all elevations to one uniform level, and the incessant quakes caused by the other satellites as they passed and repassed Europa in their orbits. Jupiter itself, despite its far greater mass, had much less effect. The Jovian tides had finished their work aeons ago, ensuring that Europa remained locked forever with one face turned toward its giant master.
All this had been known since the Voyager flyby missions of the 1970s, the Galileo surveys of the 1980s, and the Kepler landings of the 1990s. But, in a few hours, the Chinese had learned more about Europa than all the previous missions combined. That knowledge they were keeping to themselves; one might regret it, but few would deny that they had earned the right to do so.
What was being denied, with greater and greater asperity, was their right to annex the satellite. For the first time in history, a nation had laid claim to another world, and all the news media of Earth were arguing over the legal position. Though the Chinese pointed out, at tedious length, that they had never signed the '02 UN Space Treaty and so were not bound by its provisions, that did nothing to quell the angry protests.
Suddenly, Europa was the biggest news in the Solar System. And the man-on-the-spot (at least to the nearest few million kilometres) was in great demand.
"This is Heywood Floyd, aboard Cosmonaut Alexei Leonov, on course for Jupiter. But as you can well imagine, all our thoughts are now focused upon Europa.
"At this very moment I'm looking at it through the most powerful of the ship's telescopes; under this magnification, it's ten times larger than the Moon as you see it with the naked eye. And it's a really weird sight.
"The surface is a uniform pink, with a few small brown patches. It's covered with an intricate network of narrow lines, curling and weaving in all directions. In fact, it looks very much like a photo from a medical textbook, showing a pattern of veins and arteries.
"A few of these features are hundreds - or even thousands - of kilometres long, and look rather like the illusory canals that Percival Lowell and other
early-twentieth-century astronomers imagined they'd seen on Mars.
"But Europa's canals aren't an illusion, though of course they're not artificial. What's more, they do contain water - or at least ice. For the satellite is almost entirely covered by ocean, averaging fifty kilometres deep.
"Because it's so far from the sun, Europa's surface temperature is extremely low - about a hundred and fifty degrees below freezing. So one might expect its single ocean to be a solid block of ice.
"Surprisingly, that isn't the case because there's a lot of heat generated inside Europa by tidal forces - the same forces that drive the great volcanoes on neighbouring Io.
"So the ice is continually melting, breaking up, and freezing, forming cracks and lanes like those in the floating ice sheets in our own polar regions. It's that intricate tracery of cracks I'm seeing now; most of them are dark and very ancient - perhaps millions of years old. But a few are almost pure white; they're the new ones that have just opened up, and have a crust only a few centimetres thick.
"Tsien has landed right beside one of these white streaks - the fifteen-hundred-kilometre-long feature that's been christened the Grand Canal. Presumably the Chinese intend to pump its water into their propellant tanks, so that they can explore the Jovian satellite system and then return to Earth. That may not be easy, but they'll certainly have studied the landing site with great care, and must know what they're doing.
"It's obvious, now, why they've taken such a risk - and why they should claim Europa. As a refuelling point, it could be the key to the entire outer Solar System. Though there's also water on Ganymede, it's all frozen, and also less accessible because of that satellite's more powerful gravity.
"And there's another point that's just occurred to me. Even if the Chinese do get stranded on Europa, they might be able to survive until a rescue mission is arranged. They have plenty of power, there may be useful minerals in the area - and we know that the Chinese are the experts on synthetic-food production. It wouldn't be a very luxurious life; but I have some friends who would accept it happily for that staggering view of Jupiter sprawled across the sky - the view we expect to see ourselves, in just a few days.