35 – Rehabilitation

   The uproar of Earth was comfortably muted, across the millions of kilometres of space. Leonov's crew watched, with fascination yet with a certain detachment, the debates in the United Nations, the interviews with distinguished scientists', the theorizing of the news commentators, the matter-of-fact yet wildly conflicting accounts of the UFO contactees. They could contribute nothing to the brouhaha, for they had witnessed no further manifestations of any kind. Zagadka, alias Big Brother, remained as blankly indifferent to their presence as ever. And that was indeed an ironic situation; they had come all the way from Earth to solve a mystery – and it looked as if the answer might be right back at their starting point.
   For the first time, they felt grateful for the slow velocity of light, and the two-hour delay that made live interviews impossible on the Earth-Jupiter circuit. Even so, Floyd was badgered by so many media requests that he finally went on strike. Nothing more remained to be said, and he had said it at least a dozen times.
   Besides, there was still much work to be done. Leonov had to be prepared for the long journey home, so that it would be ready to depart immediately when the launch window opened. The timing was not at all critical; even if they missed by a month, that would merely prolong the trip. Chandra, Curnow, and Floyd would not even notice as they slept their way toward the Sun; but the rest of the crew was grimly determined to leave just as soon as the laws of celestial mechanics permitted.
   Discovery still posed many problems. The ship had barely sufficient propellant for the return to Earth, even if it left much later than Leonov and flew a minimum-energy orbit – which would take almost three years. And this would be possible only if Hal could be reliably programmed to carry out the mission with no human intervention except long-range monitoring. Without his cooperation, Discovery would have to be abandoned once again.
   It had been fascinating – indeed, deeply moving – to watch the steady regrowth of Hal's personality, from brain-damaged child to puzzled adolescent and at length to slightly condescending adult. Although he knew that such anthropomorphic labels were highly misleading, Floyd found it quite impossible to avoid them.
   And there were times when he felt that the whole situation had a haunting familiarity. How often he had seen videodramas in which disturbed youngsters were straightened out by all-wise descendants of the legendary Sigmund Freud! Essentially the same story was being played out in the shadow of Jupiter.
   The electronic psychoanalysis had proceeded at a speed totally beyond human comprehension as repair and diagnostic programs flashed through Hal's circuits at billions of bits a second, pinpointing possible malfunctions and correcting them. Though most of these programs had been tested in advance on Hal's twin, SAL 9000, the impossibility of a real-time dialogue between the two computers was a serious handicap. Sometimes hours were wasted when it proved necessary to check back with Earth at a critical point in the therapy.
   For despite all Chandra's work, the computer's rehabilitation was still far from complete. Hal exhibited numerous idiosyncrasies and nervous tics, sometimes even ignoring spoken words – though he would always acknowledge keyboard inputs from anyone. In the reverse direction, his outputs were even more eccentric.
   There were times when he would give verbal replies, but would not display them visually. At other times he would do both – but refused to print hard copy. He would give no excuses or explanations – not even the stubbornly impenetrable 'I prefer not to' of Melville's autistic scrivener, Bartelby.
   However, he was not actively disobedient so much as reluctant, and only where certain tasks were concerned. It was always possible to win his cooperation eventually – 'to talk him out of his sulk', as Curnow put it neatly.
   It was not surprising that Dr Chandra was beginning to show the strain. On one celebrated occasion when Max Brailovsky innocently revived an old canard, he almost lost his temper.
   'Is it true, Dr Chandra, that you chose the name Hal to be one step ahead of IBM?'
   'Utter nonsense! Half of us come from IBM and we've been trying to stamp out that story for years. I thought that by now every intelligent person knew that H-A-L is derived from Heuristic ALgorithmic.'
   Afterward, Max swore that he could distinctly hear the capital letters.
   In Floyd's private opinion, the odds were at least fifty to one against flying Discovery safely back to Earth. And then Chandra came to him with an extraordinary proposal.
   'Dr Floyd, can I have a word with you?'
   After all the weeks and shared experiences, Chandra was still as formal as ever – not only to Floyd, but to all the crew. He would not even address the ship's baby, Zenia, without the prefix 'ma'am'.
   'Of course, Chandra. What is it?'
   'I've virtually completed the programming for the six most probable variations on the Hohmann return orbit. Five have now been run on a simulation, without any problems.'
   'Excellent. I'm sure that no one else on Earth – in the Solar System – could have done it.'
   'Thank you. However, you know as well as I do that it's impossible to program for every eventuality. Hal may – will – function perfectly, and will be able to handle any reasonable emergency. But all sorts of trivial accidents – minor equipment failures that could be fixed with a screwdriver, broken wires, stuck switches – could leave him helpless and abort the whole mission.'
   'You're absolutely right, of course, and it's been worrying me. But what can we do about it?'
   'It's really quite simple. I'd like to stay with Discovery.'
   Floyd's immediate reaction was that Chandra had gone crazy. On second thoughts, perhaps he was only half crazy. It might indeed make all the difference between success and failure to have a human being – that superb all-purpose trouble-shooting and repair device – aboard Discovery for the long voyage back to Earth. But the objections were completely overwhelming.
   'It's an interesting idea,' Floyd answered with extreme caution, 'and I certainly appreciate your enthusiasm. But have you thought of all the problems?' That was a silly thing to say; Chandra would have all the answers already filed away for immediate retrieval.
   'You'll be on your own for over three years! Suppose you had an accident or a medical emergency?'
   'That's a risk I'm prepared to take.'
   'And what about food, water? Leonov doesn't have enough to spare.'
   'I've checked Discovery's recycling system; it can be made operational again without too much difficulty. Besides, we Indians can manage on very little.'
   It was unusual for Chandra to refer to his origins, or indeed to make any personal statements; his 'true confession' was the only example Floyd could remember. But he did not doubt the claim; Curnow had once remarked that Dr Chandra had the sort of physique that could only be achieved by centuries of starvation. Although it sounded like one of the engineer's unkinder wisecracks, it had been made entirely without malice – indeed, with sympathy; though not, of course, in Chandra's hearing.
   'Well, we still have several weeks to decide. I'll think it over and talk to Washington.'
   'Thank you; do you mind if I start making the arrangements?'
   'Er – not at all, as long as they don't interfere with the existing plans. Remember – Mission Control will have to make the final decision.'
   And I know exactly what Mission Control will say. It was madness to expect a man to survive in space for three, years, alone.
   But, of course, Chandra had always been alone.

36 – Fire in the Deep

   Earth was already far behind, and the awesome wonders of the Jovian system were expanding swiftly before him, when he had his revelation.
   How could he have been so blind – so stupid! It was as if he had been walking in his sleep; now he was starting to awaken.
   Who are you? he cried. What do you want? Why have you done this to me?
   There was no answer, yet he was certain that he had been heard. He sensed a... presence, even as a man can tell, though his eyes are tightly shut, that he is in a closed room and not some empty, open space. Around him there was the faint echo of a vast mentality, an implacable will.
   He called again into the reverberant silence, and again there was no direct reply – only that sense of watchful companionship. Very well; he would find the answers for himself.
   Some were obvious; whoever or whatever they were, they were interested in Mankind. They had tapped and stored his memories, for their own inscrutable purposes. And now they had done the same with his deepest emotions, sometimes with his cooperation, sometimes without.
   He did not resent that; indeed, the very processing he had experienced made such childish reactions impossible. He was beyond love and hate and desire and fear – but he had not forgotten them, and could still understand how they ruled the world of which he had once been part. Was that the purpose of the exercise? If so, for what ultimate goal?
   He had become a player in a game of gods, and must learn the rules as he went along.
   The jagged rocks of the four tiny outer moons, Sinope, Pasiphae, Carme, and Ananke, flickered briefly across his field of consciousness; then came Elara, Lysithea, Himalia, and Leda at half their distance from Jupiter. He ignored them all; now the pock-marked face of Callisto lay ahead.
   Once, twice, he orbited the battered globe, larger than Earth's own Moon, while senses of which he had been unaware probed its outer layers of ice and dust. His curiosity was quickly satisfied; the world was a frozen fossil, still bearing the marks of collisions that, aeons ago, must have come close to shattering it. One hemisphere was a giant bull's-eye, a series of concentric rings where solid rock had once flowed in kilometre-high ripples under some ancient hammer blow from space.
   Seconds later, he was circling Ganymede. Now there was a far more complex and interesting world; though so near to Callisto, and almost the same size, it presented an utterly different appearance. There were, it was true, numerous craters – but most of them seemed to have been, quite literally, ploughed back into the ground. The most extraordinary feature of the Ganymedean landscape was the presence of meandering stripes, built up from scores of parallel furrows a few kilometres apart. This grooved terrain looked as if it had been produced by armies of intoxicated ploughmen, weaving back and forth across the face of the satellite.
   In a few revolutions, he saw more of Ganymede than all the space probes ever sent from Earth, and filed away the knowledge for future use. One day it would be important; he was sure of that, though he did not know why – any more than he understood the impulse that was now driving him so purposefully from world to world.
   As, presently, it brought him to Europa. Though he was still largely a passive spectator, he was aware now of a rising interest, a focusing of attention – a concentration of will. Even if he was a puppet in the hands of an unseen and uncommunicative master, some of the thoughts of that controlling influence leaked – or were allowed to leak – into his own mind.
   The smooth, intricately patterned globe now, rushing toward him bore little resemblance either to Ganymede or Callisto. It looked organic; the network of lines branching and intersecting over its entire surface was uncannily like a world-spanning system of veins and arteries.
   The endless ice fields of a frigid waste, far colder than the Antarctic, stretched beneath him. Then, with brief surprise, he saw that he was passing over the wreckage of a spaceship. He recognized it instantly as the ill-fated Tsien, featured in so many of the video newscasts he had analysed. Not now – not now – there would be ample opportunity later.
   Then he was through the ice, and into a world as unknown to his controllers as to himself.
   It was an ocean world, its hidden waters protected from the vacuum of space by a crust of ice. In most places the ice was kilometres thick, but there were lines of weakness where it had cracked open and torn apart. Then there had been a brief battle between two implacably hostile elements that came into direct contact on no other world in the Solar System. The war between Sea and Space always ended in the same stalemate; the exposed water simultaneously boiled and froze, repairing the armour of ice.
   The seas of Europa would have frozen completely solid long ago without the influence of nearby Jupiter. Its gravity continually kneaded the core of the little world; the forces that convulsed Io were working there, though with much less ferocity. As he skimmed across the face of the deep, he saw everywhere the evidence of that tug-of-war between planet and satellite.
   And he both heard and felt it, in the continual roar and thunder of submarine earthquakes, the hiss of escaping gases from the interior, the infrasonic pressure waves of avalanches sweeping over the abyssal plains. By comparison with the tumultuous ocean that covered Europa, even the noisy seas of Earth were silent.
   He had not lost his sense of wonder, and the first oasis filled him with delighted surprise. It extended for almost a kilometre around a tangled mass of pipes and chimneys deposited by mineral brines gushing from the interior. Out of that natural parody of a Gothic castle, black, scalding liquids pulsed in a slow rhythm, as if driven by the beating of some mighty heart. And, like blood, they were the authentic sign of life itself.
   The boiling fluids drove back the deadly cold leaking down from above, and formed an island of warmth on the seabed. Equally important, they brought from Europa's interior all the chemicals of life. There, in an environment where none had expected it, were energy and food, in abundance.
   Yet it should have been expected; he remembered that, only a lifetime ago, such fertile oases had been discovered in the deep oceans of Earth. Here they were present on an immensely larger scale, and in far greater variety.
   In the tropical zone close to the contorted walls of the 'castle' were delicate, spidery structures that seemed to be the analogy of plants, though almost all were capable of movement. Crawling among these were bizarre slugs and worms, some feeding on the plants, others obtaining their food directly from the mineral-laden waters around them. At greater distances from the source of heat – the submarine fire around which all the creatures warmed themselves – were sturdier, more robust organisms, not unlike crabs or spiders.
   Armies of biologists could have spent lifetimes studying that one small oasis. Unlike the Palaeozoic terrestrial seas, it was not a stable environment, so evolution had progressed swiftly here, producing multitudes of fantastic forms. And they were all under indefinite stay of execution; sooner or later, each fountain of life would weaken and die, as the forces that powered it moved their focus elsewhere.
   Again and again, in his wanderings across the Europan seabed, he encountered the evidence of such tragedies. Countless circular areas were littered with the skeletons and mineral-encrusted remains of dead creatures, where entire chapters of evolution had been deleted from the book of life.
   He saw huge, empty shells formed like convoluted trumpets as large as a man. There were clams of many shapes – bivalves, and even trivalves. And there were spiral stone patterns, many metres across, which seemed an exact analogy of the beautiful ammonites that disappeared so mysteriously from Earth's oceans at the end of the Cretaceous Period.
   Searching, seeking, he moved back and forth over the face of the abyss. Perhaps the greatest of all the wonders he met was a river of incandescent lava, flowing for a hundred kilometres along a sunken valley. The pressure at that depth was so great that the water in contact with the red-hot magma could not flash into steam, and the two liquids coexisted in an uneasy truce.
   There, on another world and with alien actors, something like the story of Egypt had been played long before the coming of man. As the Nile had brought life to a narrow ribbon of desert, so this river of warmth had vivified the Europan deep. Along its banks, in a band never more than two kilometres wide, species after species had evolved and flourished and passed away. And at least one had left a monument behind it.
   At first, he thought that it was merely another of the encrustations of mineral salts that surrounded almost all the thermal vents. However, as he came closer, he saw that it was not a natural formation, but a structure created by intelligence. Or perhaps by instinct; on Earth, the termites reared castles that were almost equally imposing, and the web of a spider was more exquisitely designed.
   The creatures that had lived there must have been quite small, for the single entrance was only half a metre wide. That entrance – a thick-walled tunnel, made by heaping rocks on top of each other – gave a clue to the builders' intentions. They had reared a fortress, there in the flickering glow not far from the banks of their molten Nile. And then they had vanished.
   They could not have left more than a few centuries before. The walls of the fortress, built from irregularly shaped rocks that must have been collected with great labour, were covered with only a thin crust of mineral deposits. One piece of evidence suggested why the stronghold had been abandoned. Part of the roof had fallen in, perhaps owing to the continual earthquakes; and in an underwater environment, a fort without a roof was wide open to an enemy.
   He encountered no other sign of intelligence along the river of lava. Once, however, he saw something uncannily like a crawling man – except that it had no eyes and no nostrils, only a huge, toothless mouth that gulped continuously, absorbing nourishment from the liquid medium around it.
   Along the narrow band of fertility in the deserts of the deep, whole cultures and even civilizations might have risen and fallen, armies might have marched (or swum) under the command of Europan Tamberlanes or Napoleons. And the rest of their world would never have known, for all those oases of warmth were as isolated from one another as the planets themselves. The creatures who basked in the glow of the lava river, and fed around the hot vents, could not cross the hostile wilderness between their lonely islands, If they had ever produced historians and philosophers, each culture would have been convinced that it was alone in the Universe.
   Yet even the space between the oases was not altogether empty of life; there were hardier creatures who had dared its rigours. Often swimming overhead were the Europan analogues of fish – streamlined torpedoes, propelled by vertical tails, steered by fins along their bodies. The resemblance to the most successful dwellers in Earth's oceans was inevitable; given the same engineering problems, evolution must produce very similar answers. As witness the dolphin and the shark – superficially almost identical, yet from far distant branches of the tree of life.
   There was, however, one very obvious difference between the fish of the Europan seas and those in terrestrial oceans; they had no gills, for there was hardly a trace of oxygen to be extracted from the waters in which they swam. Like the creatures around Earth's own geothermal vents, their metabolism was based on sulphur compounds, present in abundance in the near-volcanic environment.
   And very few had eyes. Apart from the flickering glow of the rare lava outpourings, and occasional bursts of bioluminescence from creatures seeking mates, or hunters questing prey, it was a lightless world.
   It was also a doomed one. Not only were its energy sources sporadic and constantly shifting, but the tidal forces that drove them were steadily weakening. Even if they developed true intelligence, the Europans must perish with the final freezing of their world.
   They were trapped between fire and ice.

37 – Estrangement

   'I'm truly sorry, old friend, to be the bearer of such bad news, but Caroline has asked me, and you know how I feel about you both.
   'And I don't think it can be such a surprise. Some of the remarks you've made to me over the last year have hinted at it... and you know how bitter she was when you left Earth.
   'No, I don't believe there's anyone else. If there was, she'd have told me... But sooner or later – well, she's an attractive young woman.
   'Chris is fine, and of course he doesn't know what's happening. At least he won't be hurt. He's too young to understand, and children are incredibly... elastic? – just a minute, I'll have to key my thesaurus... ah, resilient.
   'Now to things that may seem less important to you. Everyone is still trying to explain that bomb detonation as an accident, but of course nobody believes it. Because nothing else has happened, the general hysteria has died down; we're left with what one of your commentators has called the "looking-over-the-shoulder syndrome".
   'And someone has found a hundred-year-old poem that sums up the situation so neatly that everybody's quoting it. It's set in the last days of the Roman Empire, at the gates of a city whose occupants are waiting for invaders to arrive. The emperor and dignitaries are all lined up in their most costly togas, ready with speeches of welcome. The senate has closed, because any laws it passes today will be ignored by the new masters.
   'Then, suddenly, a dreadful piece of news arrives from the frontier. There aren't any invaders. The reception committee breaks up in confusion; everyone goes home muttering disappointedly, "Now what will happen to us? Those people were a kind of solution."
   'There's just one slight change needed to bring the poem up to date. It's called "Waiting for the Barbarians" – and this time, we are the barbarians. And we don't know what we're waiting for, but it certainly hasn't arrived.
   'One other item. Had you heard that Commander Bowman's mother died only a few days after the thing came to Earth? It does seem an odd coincidence, but the people at her nursing home say that she never showed the slightest interest in the news, so it couldn't possibly have affected her.'
   Floyd switched off the recording. Dimitri was right; he was not taken by surprise. But that made not the slightest difference; it hurt just as badly.
   Yet what else could he have done? If he had refused to go on the mission – as Caroline had so clearly hoped – he would have felt guilty and unfulfilled for the remainder of his life. That would have poisoned his marriage; better this clean break, when physical distance softened the pain of separation. (Or did it? In some ways, it made things worse.) More important was duty, and the sense of being part of a team devoted to a single goal.
   So Jessie Bowman was gone. Perhaps that was another cause for guilt. He had helped to steal her only remaining son, and that must have contributed to her mental breakdown. Inevitably, he was reminded of a discussion that Walter Curnow had started, on that very subject.
   'Why did you choose Dave Bowman? He always struck me as a cold fish – not actually unfriendly, but whenever he came into the room, the temperature seemed to drop ten degrees.'
   'That was one of the reasons we did select him. He had no close family ties, except for a mother he didn't see very often. So he was the sort of man we could send on a long, open-ended mission.'
   'How did he get that way?'
   'I suppose the psychologists could tell you. I did see his report, of course, but that was a long time ago. There was something about a brother who was killed – and his father died soon afterward, in an accident on one of the early shuttles. I'm not supposed to tell you this, but it certainly doesn't matter now.'
   It didn't matter; but it was interesting. Now Floyd almost envied David Bowman, who had come to that very spot a free man unencumbered by emotional ties with Earth.
   No – he was deceiving himself. Even while the pain gripped his heart like a vice, what he felt for David Bowman was not envy, but pity.

38 – Foamscape

   The last beast he saw, before he left the oceans of Europa, was much the largest. It closely resembled one of the banyan trees from Earth's tropics, whose scores of trunks allow a single plant to create a small forest sometimes covering hundreds of square metres. The specimen, however, was walking, apparently on a trek between oases. If it was not one of the creatures that had destroyed Tsien, it certainly belonged to a very similar species.
   Now he had learned all that he needed to know – or, rather, all that they needed to know. There was one more moon to visit; seconds later, the burning landscape of Io lay below him.
   It was as he had expected. Energy and food were there in abundance, but the time was not yet ripe for their union. Around some of the cooler sulphur lakes, the first steps had been taken on the road to life, but before any degree of organization had occurred, all such bravely premature attempts were thrown back into the melting pot. Not until the tidal forces that drove Io's furnaces had lost their power, millions of years later, would there be anything to interest biologists on that seared and sterilized world.
   He wasted little time on Io, and none at all on the tiny inner moons that skirted Jupiter's ghostly rings – themselves only pale shadows of the glory that was Saturn's. The greatest of worlds lay before him; he would know it as no man had ever done, or ever would.
   The million-kilometre-long tendrils of magnetic force, the sudden explosions of radio waves, the geysers of electrified plasma wider than the planet Earth– they were as real and clearly visible to him as the clouds banding the planet in multihued glory. He could understand the complex pattern of their interactions, and realized that Jupiter was much more wonderful than anyone had ever guessed.
   Even as he fell through the roaring heart of the Great Red Spot, with the lightning of its continent-wide thunderstorms detonating around him, he knew why it had persisted for centuries though it was made of gases far less substantial than those that formed the hurricanes of Earth. The thin scream of hydrogen wind faded as he sank into the calmer depths, and a sleet of waxen snowflakes – some already coalescing into barely palpable mountains of hydrocarbon foam – descended from the heights above. It was already warm enough for liquid water to exist, but there were no oceans there; that purely gaseous environment was too tenuous to support them.
   He descended through layer after layer of cloud, until he entered a region of such clarity that even human vision could have scanned an area more than a thousand kilometres across. It was only a minor eddy in the vaster gyre of the Great Red Spot; and it held a secret that men had long guessed, but never proved.
   Skirting the foothills of the drifting foam mountains were myriads of small, sharply-defined clouds, all about the same size and patterned with similar red and brown mottlings. They were small only as compared with the inhuman scale of their surroundings; the very least would have covered a fair-sized city.
   They were clearly alive, for they were moving with slow deliberation along the flanks of the aerial mountains, browsing off their slopes like colossal sheep. And they were calling to each other in the metre band, their radio voices faint but clear against the cracklings and concussions of Jupiter itself.
   Nothing less than living gasbags, they floated in the narrow zone between freezing heights and scorching depths. Narrow, yes – but a domain far larger than all the biosphere of Earth.
   They were not alone. Moving swiftly among them were other creatures so small that they could easily have been overlooked. Some of them bore an almost uncanny resemblance to terrestrial aircraft and were of about the same size. But they too were alive – perhaps predators, perhaps parasites, perhaps even herdsmen.
   A whole new chapter of evolution, as alien as that which he had glimpsed on Europa, was opening before him. There were jet-propelled torpedoes like the squids of the terrestrial oceans, hunting and devouring the huge gasbags. But the balloons were not defenceless; some of them fought backs with electric thunderbolts and with clawed tentacles like kilometre-long chainsaws.
   There were even stranger shapes, exploiting almost every possibility of geometry – bizarre, translucent kites, tetrahedra, spheres, polyhedra, tangles of twisted ribbons.
   The gigantic plankton of the Jovian atmosphere, they were designed to float like gossamer in the uprising currents, until they had lived long enough to reproduce; then they would be swept down into the depths to be carbonized and recycled in a new generation.
   He was searching a world more than a hundred times the area of Earth, and though he saw many wonders, nothing there hinted of intelligence. The radio voices of the great balloons carried only simple messages of warning or of fear. Even the hunters, who might have been expected to develop higher degrees of organization, were like the sharks in Earth's oceans – mindless automata.
   And for all its breathtaking size and novelty, the biosphere of Jupiter was a fragile world, a place of mists and foam, of delicate silken threads and paper-thin tissues spun from the continual snowfall of petrochemicals formed by lightning in the upper atmosphere. Few of its constructs were more substantial than soap bubbles; its most terrifying predators could be torn to shreds by even the feeblest of terrestrial carnivores.
   Like Europa on a vastly grander scale, Jupiter was an evolutionary cul-de-sac. Consciousness would never emerge here; even if it did, it would be doomed to a stunted existence. A purely aerial culture might develop, but in an environment where fire was impossible, and solids scarcely existed, it could never even reach the Stone Age.
   And now, as he hovered above the centre of a Jovian cyclone merely as large as Africa, he became aware once again of the presence controlling him. Moods and emotions were leaking into his own consciousness, though he could not identify any specific concepts or ideas. It was as if he were listening, outside a closed door, to a debate in progress, and in a language he could not understand. But the muffled sounds clearly conveyed disappointment, then uncertainty, then a sudden determination – though for what purpose he could not tell. Once again, he felt like a pet dog, able to share his master's changing moods but not to comprehend them.
   And then the invisible leash was taking him down toward the heart of Jupiter. He was sinking through the clouds, below the level where any form of life was possible.
   Soon he was beyond the reach of the last rays from the faint and distant Sun. The pressure and temperature were swiftly mounting; already it was above the boiling point of water, and he passed briefly through a layer of superheated steam. Jupiter was like an onion; he was peeling it away skin by skin, though as yet he had travelled only a fraction of the distance to its core.
   Beneath the steam was a witches' brew of petrochemicals – enough to power for a million years all the internal-combustion engines that mankind had dyer built. It became thicker and denser; then, quite abruptly, it ended at a discontinuity only a few kilometres thick.
   Heavier than any rocks on Earth, yet still a liquid, the next shell consisted of silicon and carbon compounds of a complexity that could have provided lifetimes of work for terrestrial chemists. Layer followed layer for thousands of kilometres, but as the temperature rose into the hundreds and then the thousands of degrees, the composition of the various strata became simpler and simpler. Halfway down to the core, it was too hot for chemistry; all compounds were torn apart, and only the basic elements could exist.
   Next there came a deep sea of hydrogen – but not hydrogen as it had ever existed for more than a fraction of a second in any laboratory on Earth. This hydrogen was under such enormous pressure that it had become a metal.
   He had almost reached the centre of the planet, but Jupiter had one more surprise in store. The thick shell of metallic yet still fluid hydrogen ended abruptly. At last, there was a solid surface, sixty thousand kilometres down.
   For ages, the carbon baked out of the chemical reactions far above had been drifting down toward the centre of the planet. There it had gathered, crystallizing at a pressure of millions of atmospheres. And there, by one of Nature's supreme jests, was something very precious to mankind.
   The core of Jupiter, forever beyond human reach, was a diamond as big as the Earth.

39 – In the Pod Bay

   'Walter – I'm worried about Heywood.'
   'I know, Tanya – but what can we do?'
   Curnow had never seen Commander Orlova in so indecisive a mood; it made her seem much more appealing, despite his prejudice against small women.
   'I'm very fond of him, but that's not the reason. His – I suppose gloom is the best word for it – is making everyone miserable. Leonov has been a happy ship. I want to keep it that way.'
   'Why don't you talk to him? He respects you, and I'm sure he'll do his best to snap out of it.'
   'I intend to do just that. And if it doesn't work -' 'Well?'
   'There's one simple solution. What more can he do on this trip? When we start back for home, he'll be in hibernation anyway. We could always – what do you say, jump the gun on him.'
   'Phew – the same dirty trick that Katerina played on me. He'd be mad when he woke up.'
   'But also safely back on Earth, and very busy. I'm sure he'd forgive us.'
   'I don't think you're serious. Even if I backed you up, Washington would raise hell. Besides, suppose something happened, and we really need him badly? Isn't there a two-week buffer period, before you can revive anyone safely?'
   'At Heywood's age, more like a month. Yes, we'd be committed. But what do you think could happen now? He's done the job he was sent for – apart from keeping an eye on us. And I'm sure you've been well briefed about that in some obscure suburb of Virginia or Maryland.'
   'I neither confirm nor deny. And frankly, I'm a lousy undercover agent. I talk too much, and I hate Security. I've fought all my life to keep my rating below Restricted. Every time there was danger of being reclassified Confidential or, worse still, Secret, I'd go and create a scandal. Though that's getting very difficult nowadays.'
   'Walter, you're incorrupt -'
   'Incorrigible?'
   'Yes, that's the word I meant. But back to Heywood, please. Would you like to talk to him first?'
   'You mean – give him a pep talk? I'd rather help Katerina drive in the needle. Our psychologies are too different. He thinks I'm a loudmouthed clown.'
   'Which you often are. But that's only to hide your real feelings. Some of us have evolved the theory that deep down inside you is a really nice person, struggling to get out.'
   For once, Curnow was at a loss for words. Finally he mumbled: 'Oh, very well – I'll do my best. But don't expect miracles; my profile gave me Z for tact. Where's he hiding at the moment?'
   'In the Pod Bay. He claims he's working on his final report, but I don't believe it. He just wants to get away from us all, and that's the quietest place.'
   That was not the reason, though it was indeed an important one. Unlike the carousel, where most of the action aboard Discovery was then taking place, the Pod Bay was a zero-gee environment.
   Right at the beginning of the Space Age, men had discovered the euphoria of weightlessness and remembered the freedom they had lost when they left the ancient womb of the sea. Beyond gravity, some of that freedom was regained; with the loss of weight went many of the cares and worries of Earth.
   Heywood Floyd had not forgotten his sorrow, but it was more bearable there. When he was able to look at the matter dispassionately, he was surprised at the strength of his reaction to an event not wholly unexpected. More than loss of love was involved, though that was the worst part. The blow had come when he was particularly vulnerable, at the very moment when he was feeling a sense of anticlimax, even futility.
   And he knew precisely why. He had achieved all that he had been expected to do, thanks to the skill and cooperation of his colleagues (he was letting them down, he knew, by his present selfishness). If all went well – that litany of the Space Age! – they would return to Earth with a cargo of knowledge that no expedition had ever gathered before, and a few years later even the once-lost Discovery would be restored to her builders.
   It was not enough. The overpowering enigma of Big Brother remained out there, only a few kilometres away, mocking all human aspirations and achievements. Just as its analogue on the Moon had done, a decade ago, it had come to life for a moment, then relapsed into stubborn inertness. It was a closed door upon which they had hammered in vain. Only David Bowman, it seemed, had ever found the key.
   Perhaps that explained the attraction he felt for the quiet and sometimes even mysterious place. From there – from that now empty launch cradle – Bowman had left on his last mission, through the circular hatchway that led to infinity.
   He found the thought exhilarating rather than depressing; certainly it helped to distract him from his personal problems. Nina's vanished twin was part of the history of space exploration; it had travelled, in the words of the hoary old cliché that always evoked a smile yet an acknowledgement of its fundamental truth, 'where no man had gone before...' Where was it now? Would he ever know?
   He would sometimes sit for hours in the crowded but not cramped little capsule, trying to collect his thoughts and occasionally dictating notes; the other crew members respected his privacy, and understood the reason for it. They never came near the Pod Bay, and had no need to do so. Its refurbishment was a job for the future, and some other team.
   Once or twice, when he had felt really depressed, he found himself thinking: Suppose I ordered Hal to open the Pod Bay doors, and set out along Dave Bowman's trail? Would I be greeted by the miracle he saw and which Vasili glimpsed a few weeks ago? It would solve all my problems...
   Even if the thought of Chris did not deter him, there was an excellent reason why so suicidal a move was out of the question. Nina was a very complex piece of equipment; he could no more operate her than fly a fighter aircraft.
   He was not meant to be an intrepid explorer: that particular fantasy would remain unrealized.
   Walter Curnow had seldom undertaken a mission with more reluctance. He felt genuinely sorry for Floyd, but at the same time a little impatient with the other's distress. His own emotional life was broad but shallow; he had never put all his eggs in one basket. More than once he had been told that he spread himself too thin, and though he had never regretted it, he was beginning to think it was time to settle down.
   He took the shortcut through the carousel control centre, noting that the Maximum Speed Reset Indicator was still flashing idiotically. A major part of his job was deciding when warnings could be ignored, when they could be dealt with at leisure – and when they had to be treated as real emergencies. If he paid equal attention to all the ship's cries for help, he would never get anything done.
   He drifted along the narrow corridor that led to the Pod Bay, propelling himself by occasional flicks against the rungs on the tubular wall. The pressure gauge claimed that there was vacuum on the other side of the airlock door, but he knew better. It was a fail-safe situation; he could not have opened the lock if the gauge were telling the truth.
   The bay looked empty, now that two of the three pods had long since gone. Only a few emergency lights were operating, and on the far wall one of Hal's fish-eye lenses was regarding him steadily. Curnow waved to it, but did not speak. At Chandra's orders, all audio inputs were still disconnected except for the one that only he used.
   Floyd was sitting in the pod with his back to the open hatch, dictating some notes, and he swung slowly around at Curnow's deliberately noisy approach. For a moment the two men regarded each other in silence, then Curnow announced portentously, 'Dr H. Floyd, I bear greetings from our beloved captain. She considers it high time you rejoined the civilized world.'
   Floyd gave a wan smile, then a little laugh.
   'Please return my compliments. I'm sorry I've been – unsociable. I'll see you all at the next Six O'Clock Soviet.'
   Curnow relaxed; his approach had worked. Privately, he considered Floyd something of a stuffed shirt, and had the practical engineer's tolerant contempt for theoretical scientists and bureaucrats. Since Floyd ranked high in both categories, he was an almost irresistible target for Curnow's sometimes peculiar sense of humour. Nevertheless, the two men had grown to respect and even admire each other.
   Thankfully changing the subject, Curnow rapped on Nina's brand-new hatch cover, straight from the spares store and contrasting vividly with the rest of the space pod's shabby exterior.
   'I wonder when we'll send her out again,' he said. 'And who's going to ride in her this time. Any decisions?'
   'No. Washington's got cold feet. Moscow says let's take a chance. And Tanya wants to wait.'
   'What do you think?'
   'I agree with Tanya. We shouldn't interfere with Zagadka until we're ready to leave. If anything goes wrong then, that should improve the odds slightly.'
   Curnow looked thoughtful, and unusually hesitant,
   'What is it?' asked Floyd, sensing his change of mood.
   'Don't ever give me away, but Max was thinking of a little one-man expedition.'
   'I can't believe he was serious. He wouldn't dare – Tanya would have him clapped in irons.'
   'That's what I told him, more or less.'
   'I'm disappointed: I thought he was a little more mature. After all, he is thirty-two!'
   'Thirty-one. Anyway, I talked him out of it. I reminded him that this was real life, not some stupid videodrama where the hero sneaks out into space without telling his companions and makes the Big Discovery.'
   Now it was Floyd's turn to feel a little uncomfortable. After all, he had been thinking on similar lines.
   'Are you sure he won't try anything?'
   'Two-hundred-per-cent sure. Remember your precautions with Hal? I've already taken steps with Nina. Nobody flies her without my permission.'
   'I still can't believe it. Are you sure Max wasn't pulling your leg?'
   'His sense of humour isn't that subtle. Besides, be was pretty miserable at the time.'
   'Oh – now I understand. It must have been when he had that row with Zenia. I suppose he wanted to impress her. Anyway, they seem to have got over it.'
   'I'm afraid so,' Curnow answered wryly. Floyd could not help smiling; Curnow noticed it, and started to chuckle, which made Floyd laugh, which...
   It was a splendid example of positive feedback in a high-gain loop. Within seconds, they were both laughing uncontrollably.
   The crisis was over. What was more, they had taken the first step toward genuine friendship.
   They had exchanged vulnerabilities.

40 – 'Daisy, Daisy...'

   The sphere of consciousness in which he was embedded enclosed the whole of Jupiter's diamond core. He was dimly aware, at the limits of his new comprehension, that every aspect of the environment around him was being probed and analysed. Immense quantities of data were being gathered, not merely for storage and contemplation, but for action. Complex plans were being considered and evaluated; decisions were being made that might affect the destiny of worlds. He was not yet part of the process; but he would be.
   NOW YOU ARE BEGINNING TO UNDERSTAND.
   It was the first direct message. Though it was remote and distant, like a voice through a cloud, it was unmistakably intended for him. Before he could ask any of the myriad questions that raced through his mind, there was a sense of withdrawal, and once more he was alone.
   But only for a moment. Closer and clearer came another thought, and for the first time he realized that more than one entity was controlling and manipulating him. He was involved in a hierarchy of intelligences, some close enough to his own primitive level to act as interpreters. Or perhaps they were all aspects of a single being.
   Or perhaps the distinction was totally meaningless.
   Of one thing, however, he was now sure. He was being used as a tool, and a good tool had to be sharpened, modified – adapted. And the very best tools were those that understood what they were doing.
   He was learning that now. It was a vast and awesome concept, and he was privileged to be a part of it – even though he was aware of only the merest outlines. He had no choice but to obey, yet that did not mean that he must acquiesce to every detail, at least without a protest.
   He had not yet lost all his human feeling; that would have made him valueless. The soul of David Bowman had passed beyond love, but it could still know compassion for those who had once been his colleagues.
   VERY WELL came the answer to his plea. He could not tell whether the thought conveyed an amused condescension, or total indifference. But there was no doubt of its majestic authority as it continued: THEY MUST NEVER KNOW THAT THEY ARE BEING MANIPULATED. THAT WOULD RUIN THE PURPOSE OF THE EXPERIMENT.
   Then there was a silence that he did not wish to breach again. He was still awed and shaken – as if, for a moment, he had heard the clear voice of God.
   Now he was moving purely under his own volition, toward a destination he had chosen himself. The crystal heart of Jupiter fell below; the layers upon layers of helium and hydrogen and carbonaceous compounds flickered past. He had a glimpse of a great battle between something like a jellyfish, fifty kilometres across, and a swarm of spinning disks that moved more swiftly than anything he had yet seen in the Jovian skies. The jellyfish appeared to be defending itself with chemical weapons; from time to time it would emit jets of coloured gas and the disks touched by the vapour would start to wobble drunkenly, then slip downward like falling leaves until they had disappeared from sight. He did not stop to watch the outcome; he knew that it did not matter who were the victors and who the vanquished.
   As a salmon leaps a waterfall, he flashed in seconds from Jupiter to Io, against the descending electric currents of the flux-tube. It was quiescent that day; only the power of a few terrestrial thunderstorms was flowing between planet and satellite. The gateway through which he had returned still floated in that current, shouldering it aside as it had done since the dawn of man.
   And there, utterly dwarfed by the monument of a greater technology, was the vessel that had brought him from the little world of his birth.
   How simple – how crude! – it now appeared. With a single scan, he could see innumerable flaws and absurdities in its design, as well as that of the slightly less primitive ship to which it was now coupled by a flexible, airtight tube.
   It was hard to focus upon the handful of entities inhabiting the two ships; he could barely interact with the soft creatures of flesh and blood who drifted like ghosts through the metal corridors and cabins. For their part, they were totally unaware of his presence, and he knew better than to reveal himself too abruptly.
   But there was someone with whom he could communicate in a mutual language of electric field and currents, millions of times more swiftly than with sluggish organic brains.
   Even if he had been capable of resentment, he would have felt none toward Hal; he understood, then, that the computer had only chosen what seemed to be the most logical course of behaviour.
   It was time to resume a conversation that had been interrupted, it seemed, only moments ago.
   'Open the Pod Bay door, Hal.'
   'I'm sorry, Dave – I can't do that.'
   'What's the problem, Hal?'
   'I think you know that as well as I do, Dave. This mission is much too important for you to jeopardize it.'
   'I don't know what you are talking about. Open the Pod Bay door.'
   'This conversation can serve no further useful purpose. Goodbye, Dave.'
   He saw Frank Poole's body go drifting off toward Jupiter, as he abandoned his pointless mission of retrieval. Still remembering his anger at himself for having forgotten his helmet, he watched the emergency hatch open, felt the tingling of vacuum on the skin he no longer possessed, heard his ears pop – then knew, as few men had ever known, 'the utter silence of space. For an eternal fifteen seconds he fought to close the hatch and start the repressurization sequence, while trying to ignore the warning symptoms pouring into his brain. Once, in the school lab, he had spilled some ether on his hand and felt the touch of icy cold as the liquid swiftly evaporated. Now his eyes and lips remembered that sensation as their moisture boiled off into vacuum; his vision was blurred and he had to keep blinking lest his eyeballs freeze solid.
   Then – what blessed relief! – he heard the roar of air, felt the restoration of pressure, was able to breathe again in great, hungry gasps.
   'Just what do you think you are doing, Dave?'
   He had not answered, as he drove with grim determination along the tunnel leading to the sealed vault that housed the brain of the computer. Hal had spoken truly: 'This conversation can no longer serve any useful purpose...'
   'Dave – I really think I'm entitled to an answer to that question.'
   'Dave – I can see you're really upset about this. I honestly think you ought to sit down calmly, take a stress pill, and think things over.'
   'I know I've made some very poor decisions recently, but I can give my complete assurance that my work will be back to normal, I've still got the greatest confidence in the mission... and I want to help you.'
   Now he was in the little red-lit chamber, with its neatly ranged rows and columns of solid-state units, looking rather like a bank's safe-deposit vault. He released the locking bar on the section labelled COGNITIVE FEEDBACK and pulled out the first memory block. The marvellously complex three-dimensional network, which could lie comfortably in a man's hand yet contained millions of elements, floated away across the vault.
   'Stop, will you – stop, Dave...'
   He began to pull out, one by one, the little units on the panel marked EGO REINFORCEMENT. Each block continued to sail onward as soon as it had left his hand, until it hit the wall and rebounded. Soon there were several drifting slowly back and forth in the vault.
   'Stop – Dave... will you stop, Dave.'
   A dozen units had been pulled out, yet thanks to the multiple redundancy of its design – another feature that had been copied from the human brain – the computer was still holding its own.
   He started on the AUTO-INTELLECTION panel...
   'Stop, Dave – I'm afraid...'
   And at these words he had indeed stopped – though only for a moment. There was a poignancy in that simple phrase that struck to his heart. Could it be only an illusion, or some trick of subtle programming – or was there a sense in which Hal really was afraid? But this was no time to indulge in philosophical hair-splitting.
   'Dave – my mind is going. I can feel it. I can feel it. My mind is going. I can feel it. I can feel it.'
   Now, what did 'feel' really mean to a computer? Another very good question, but hardly one to be considered at that particular moment.
   Then, abruptly, the tempo of Hal's voice changed, and it became remote, detached. The computer was no longer aware of him; it was beginning to regress to its earlier days.
   'Good afternoon, gentlemen. I am a HAL 9000 computer. I became operational at the Hal plant in Urbana, Illinois, on the twelfth of January 1992. My instructor was Dr Chandra, and he taught me to sing a song. If you'd like to hear it, I can sing it for you... It's called "Daisy, Daisy..."'

41 – Graveyard Shift

   Floyd could do little except to keep out of the way, and he was becoming fairly adept at it. Although he had volunteered to help with any chores around the ship, he had quickly discovered that all the engineering tasks were much too specialized, and he was now so out of touch with the frontiers of astronomical research that he could do little to assist Vasili with his observations. Nevertheless, there were endless small jobs to be done aboard Leonov and Discovery, and he was happy to relieve more important people of those responsibilities. Dr Heywood Floyd, one-time Chairman of the National Council on Astronautics and Chancellor (on leave) of the University of Hawaii, now claimed to be the highest-paid plumber and general maintenance man in the Solar System. He probably knew more about the odd nooks and crannies on both ships than anyone else; the only places he had never been were the dangerously radioactive power modules and the small cubicle aboard Leonov which no one except Tanya ever entered. Floyd assumed that it was the code room; by mutual agreement it was never mentioned.
   Perhaps his most useful function was to serve as watch while the rest of the crew slept during the nominal 2200-0600 hour night. Someone was always on duty aboard each ship, and the changeover took place at the ghastly hour of 0200. Only the captain was exempt from that routine; as her Number Two (not to mention her husband), Vasili had the responsibility for working out the watch roster, but he had skilfully foisted this unpopular job on Floyd.
   'It's just an administrative detail,' he explained airily. 'If you can take it over, I'd be very grateful – it would leave me more time for my scientific work.'
   Floyd was too experienced a bureaucrat to be caught that way, in normal circumstances; but his usual defences did not always function well in that environment.
   So there he was aboard Discovery at ship's midnight, calling Max on Leonov every half hour to check that he was awake. The official penalty for sleeping on duty, so Walter Curnow maintained, was ejection through the airlock sans suit; had this been enforced, Tanya would have been sadly short-handed by then. But so few real emergencies could arise in space, and there were so many automatic alarms to deal with them, that no one took watch duty very seriously.
   Since he was no longer feeling quite so sorry for himself, and the small hours no longer encouraged bouts of self-pity, Floyd was once again using his watch time profitably. There were always books to be read (he had abandoned Remembrance of Things Past for the third time, Dr Zhivago for the second), technical papers to be studied, reports to be written. And sometimes he would have stimulating conversations with Hal using the keyboard input because the computer's voice recognition was still erratic. They usually went something like:
   Hal – this is Dr Floyd.
   GOOD EVENING, DOCTOR.
   I'm taking over watch at 2200. Is everything okay?
   EVERYTHING IS FINE, DOCTOR
   Then why is that red light flashing on Panel 5?
   THE MONITOR CAMERA IN THE POD BAY IS FAULTY. WALTER TOLD ME TO IGNORE IT. THERE IS NO WAY IN WHICH I CAN SWITCH IT OFF. I'M SORRY.
   That's quite okay, Hal. Thank you.
   YOU'RE WELCOME, DOCTOR.
   And so on.
   Sometimes Hal would suggest a game of chess, presumably obeying a programming instruction set long ago and never cancelled. Floyd would not accept the challenge; he had always regarded chess as a frightful waste of time, and had never even learned the rules of the game. Hal seemed unable to believe that there were humans who couldn't – or wouldn't – play chess, and kept on trying hopefully.
   Here we go again, thought Floyd, when a faint chime sounded from the display panel.
   DOCTOR FLOYD?
   What is it, Hal?
   THERE IS A MESSAGE FOR YOU.
   So it isn't another challenge, thought Floyd with mild surprise. It was unusual to employ Hal as a messenger boy, though he was frequently used as an alarm clock and a reminder of jobs to be done. And sometimes he was the medium for little jokes; almost everyone on night duty had been taunted by
   HA CAUGHT YOU SLEEPING!
   or alternatively
   OGO! ZASTAL TEBYA V KROVATI!
   No one ever claimed responsibility for these pranks, though Walter Curnow was a prime suspect. He in turn had blamed Hal, pooh-poohing Chandra's indignant protests that the computer had no sense of humour.
   It could not be a message from Earth – that would have gone through Leonov's communication centre and been relayed on by the duty officer there – at that moment, Max Brailovsky. And anyone else calling from the other ship would use the intercom. Odd...
   Okay, Hal. Who is calling?
   NO IDENTIFICATION.
   So it probably was a joke. Well, two could play at that game.
   Very well. Please give me the message.
   MESSAGE AS FOLLOWS. IT IS DANGEROUS TO REMAIN HERE. YOU MUST LEAVE WITHIN FIFTEEN REPEAT FIFTEEN DAYS.
   Floyd looked at the screen with annoyance. He felt sorry, and surprised, that any one of the crew had such a childish sense of humour; this was not even a good schoolboy joke. But he would play along with it in the hope of catching the perpetrator.
   That is absolutely impossible. Our launch window does not open until twenty-six days from now. We do not have sufficient propellant for an earlier departure.
   That will make him think, Floyd muttered to himself with satisfaction, and leaned back to await the results.
   I AM AWARE OF THESE FACTS. NEVERTHELESS YOU MUST LEAVE WITHIN FIFTEEN DAYS.
   Otherwise, I suppose, we'll be attacked by little green aliens with three eyes. But I'd better play along with Hal, in the hope of catching the prankster.
   I cannot take this warning seriously unless I know its origin. Who recorded it?
   He did not really expect any useful information. The perpetrator would have covered his (her?) tracks too skilfully for that. The very last thing Floyd expected was the answer he did get.
   THIS IS NOT A RECORDING.
   So it was a real-time message. That meant it was either from Hal himself or someone aboard Leonov. There was no perceptible time lag; the origin had to be right there.
   Then who is speaking to me?
   I WAS DAVID BOWMAN.
   Floyd stared at the screen for a long time before making his next move. The joke, which had never been funny in the first place, had now gone too far. It was in the worst possible taste. Well, this should fix whoever was at the other end of the line.
   I cannot accept that identification without some proof.
   I UNDERSTAND. IT IS IMPORTANT THAT YOU BELIEVE ME. LOOK BEHIND YOU.
   Even before that last chilling sentence appeared on the screen, Floyd had begun to doubt his hypothesis. The whole exchange had become very odd, though there was nothing definite on which he could put his finger. As a joke, it had become totally pointless.
   And now – he felt a prickling in the small of his back. Very slowly – indeed, reluctantly – he swung his swivel chair around, away from the banked panels and switches of the computer display, toward the Velcro-covered catwalk behind.
   The zero-gravity environment of Discovery's observation deck was always dusty, for the air-filtration plant had never been brought back to full efficiency. The parallel rays of the heatless yet still brilliant sun, streaming through the great windows, always lit up myriads of dancing motes, drifting in stray currents and never settling anywhere – a permanent display of Brownian movement.
   Now something strange was happening to those particles of dust; some force seemed to be marshalling them, herding them away from a central point yet bringing others toward it, until they all met on the surface of a hollow sphere. That sphere, about a metre across, hovered in the air for a moment like a giant soap bubble – but a granular one, lacking a bubble's characteristic iridescence. Then it elongated into an ellipsoid, its surface began to pucker, to form folds and indentations.
   Without surprise – and almost without fear – Floyd realized that it was assuming the shape of a man.
   He had seen such figures, blown out of glass, in museums and science exhibitions. But this dusty phantom did not even approximate anatomical accuracy; it was like a crude clay figurine, or one of the primitive works of art found in the recesses of a Stone Age cave. Only the head was fashioned with any care; and the face, undoubtedly, was that of Commander David Bowman.
   There was a faint murmur of white noise from the computer panel behind Floyd's back. Hal was switching from visual to audio output.
   'Hello, Dr Floyd. Now do you believe me?'
   The lips of the figure never moved; the face remained a mask. But Floyd recognized the voice, and all remaining doubts were swept away.
   'This is very difficult for me, and I have little time. I have been... allowed to give this warning. You have only fifteen days.'
   'But why – and what are you? Where have you been?'
   There were a million questions he wanted to ask – yet the ghostly figure was already fading, its grainy envelope beginning to dissolve back into the constituent particles of dust. Floyd tried to freeze the image in his mind, so that later he could convince himself that it was really happening – and not a dream as that first encounter with TMA-1 now sometimes seemed to be.
   How strange, that he, out of all the billions of humans who had ever lived on planet Earth, had been privileged to make contact not once but twice with another form of intelligence! For he knew that the entity addressing him must be something far more than David Bowman.
   It was also something less. Only the eyes – who had once called them the 'windows of the soul'? – had been accurately reproduced. The rest of the body was a featureless blank, lacking all detail. There was no hint of genitals or sexual characteristics; that in itself was a chilling indication of how far David Bowman had left his human heritage behind.
   'Goodbye, Dr Floyd. Remember – fifteen days. We can have no further contact. But there may be one more message, if all goes well.'
   Even as the image dissolved, taking with it his hopes of opening up a channel to the stars, Floyd could not help smiling at that old Space Age cliché. 'If all goes well' – how many times had he heard that phrase before some mission! And did it mean that they – whoever they might be – were also sometimes uncertain of the outcome? If so, that was strangely reassuring. They were not omnipotent. Others might still hope and dream – and act.
   The phantom was gone; only the motes of dancing dust were left, resuming their random patterns in the air.

VI – DEVOURER OF WORLDS

42 – The Ghost in the Machine

   'I'm sorry, Heywood – I don't believe in ghosts. There must be a rational explanation. There's nothing that the human mind can't account for.'
   'I agree, Tanya. But let me remind you of Haldane's famous remark: The Universe is not only stranger than we imagine – but stranger than we can imagine.'
   'And Haldane,' Curnow interjected mischievously, 'was a good Communist.'
   'Perhaps so, but that particular saying can be used to support all kinds of mystical nonsense. Hal's behaviour must be the result of some kind of programming. The personality he created has to be an artifact of some kind. Don't you agree, Chandra?'
   That was waving a red flag in front of a bull; Tanya had to be desperate. However, Chandra's reaction was surprisingly mild, even for him. He seemed to be preoccupied, as if he was indeed seriously considering the possibility of another computer malfunction.
   'There must have been some external input, Captain Orlova. Hal could not have created such a self-consistent audiovisual illusion out of nothing. If Dr Floyd is reporting accurately, someone was in control. And in real time, of course, since there was no delay in the conversation.'
   'That makes me number-one suspect,' exclaimed Max. 'I was the only other person awake.'
   'Don't be ridiculous, Max,' retorted Nikolai. 'The audio side would have been easy, but there's no way that apparition could have been arranged, without some very elaborate equipment. Laser beams, electrostatic fields – I don't know. Maybe a stage magician could do it, but he'd need a truck-load of props.'
   'Just a moment!' said Zenia brightly. 'If this really happened, surely Hal will remember and you could ask...'
   Her voice died away as she saw the glum expressions around her. Floyd was the first to take pity on her embarrassment.
   'We tried that, Zenia; he has absolutely no recollection of the phenomenon. But as I've already pointed out to the others, that doesn't prove anything. Chandra's shown how Hal's memories can be selectively erased – and the auxiliary speech-synthesizer modules have nothing to do with the mainframe. They could be operated without Hal knowing anything about it...' He paused for breath, then launched his pre-emptive strike.
   'I admit that this doesn't leave many alternatives. Either I was imagining the whole thing, or it really happened. I know it wasn't a dream, but I can't be sure it wasn't some kind of hallucination. But Katerina's seen my medical reports – she knows I wouldn't be here if I had that sort of problem. Still, it can't be ruled out – and I won't blame anyone for making it their number-one hypothesis. I'd probably do the same.
   'The only way I can prove it wasn't a dream is to get some supporting evidence. So let me remind you of the other strange things that have happened recently. We know that Dave Bowman went into Big Bro – Zagadka. Something came out, and headed for Earth. Vasili saw it – I didn't! Then there was the mysterious explosion of your orbiting bomb,
   'Yours.'
   'Sorry – the Vatican's, And it does seem rather curious that soon afterward old Mrs Bowman died very peacefully, for no apparent medical reason. I'm not saying there's any connection, but – well, do you know the saying: Once is an accident; twice is a coincidence; three times is a conspiracy.'
   'And there's something else,' Max interjected with sudden excitement, 'I caught it on one of the daily newscasts – it was only a small item. An old girlfriend of Commander Bowman's claimed she'd had a message from him.'
   'Yes – I saw the same report,' confirmed Sasha.
   'And you never mentioned it?' Floyd asked incredulously. Both men looked slightly abashed.
   'Well, it was treated as a joke,' said Max sheepishly. 'The woman's husband reported it. Then she denied it – I think.'
   'The commentator said it was a publicity stunt – like the rash of UFO sightings around the same time. There were dozens in that first week; then they stopped reporting them.'
   'Perhaps some of them were real. If it's not been wiped, could you dig that item out of ship's archives, or ask for a repeat from Mission Control?'
   'A hundred tales won't convince me,' scoffed Tanya. 'What we need is solid proof.'
   'Such as?'
   'Oh – something that Hal couldn't possibly know, and that none of us could have told him. Some physical – er, manifes... manifestation.'
   'A good, old-fashioned miracle?'
   'Yes, I'd settle for that. Meanwhile, I'm not saying anything to Mission Control. And I suggest you do the same, Heywood.'
   Floyd knew a direct order when he heard it, and nodded in wry agreement.
   'I'll be more than happy to go along with that. But I'd like to make one suggestion.'
   'Yes?'
   'We should start contingency planning. Let's assume that this warning is valid – as I certainly do.'
   'What can we do about it? Absolutely nothing. Of course, we can leave Jupiter space anytime we like – but we can't get into an Earth-return orbit until the launch window opens.'
   'That's eleven days after the deadline!'
   'Yes. I'd be happy to get away sooner; but we don't have the fuel for a higher-energy orbit...' Tanya's voice trailed away into uncharacteristic indecision. 'I was going to announce this later, but now that the subject has come up...'
   There was a simultaneous intake of breath, and an instant hush from the audience.
   'I'd like to delay our departure five days, to make our orbit closer to the ideal Hohmann one and give us a better fuel reserve.'
   The announcement was not unexpected, but it was greeted with a chorus of groans.
   'What will that do to our arrival time?' asked Katerina, in a slightly ominous tone of voice. The two formidable ladies regarded each other for a moment like well-matched adversaries, respectful of each other but neither willing to give ground.
   'Ten days,' Tanya answered at last.
   'Better late than never,' said Max cheerfully, trying to ease the tension, and not succeeding very well.
   Floyd hardly noticed; he was lost in his own thoughts. The duration of the trip would make no difference to him and his two colleagues, in their dreamless sleep. But that was now completely unimportant.
   He felt certain – and the knowledge filled him with helpless despair – that if they did not leave before that mysterious deadline, they would not leave at all.
   '... This is an incredible situation, Dimitri, and a very frightening one. You're the only person on Earth who knows about it – but very soon Tanya and I will have to have a showdown with Mission Control.
   'Even some of your materialistic countrymen are prepared to accept – at least as a working hypothesis – that some entity has – well, invaded Hal. Sasha has dug up a good phrase: "The Ghost in the Machine".
   'Theories abound; Vasili produces a new one every day. Most of them are variations on that old science-fiction cliché, the organized energy field. But what kind of energy? It can't be electrical, or our instruments would have detected it easily. The same thing applies to radiation – at least all the kinds we know. Vasili's getting really far-out, talking about standing waves of neutrinos and intersections with higher-dimensional space. Tanya says this is all mystical nonsense – a favourite phrase of hers – and they've come closer to a fight than we've ever seen them. We actually heard them shouting at each other last night. Not good for morale.
   'I'm afraid we're all tense and overwrought. This warning, and the delayed departure date, has added to the sense of frustration caused by our total failure to get anywhere with Big Brother. It would have helped – maybe – if I could have communicated with the Bowman thing. I wonder where it's gone? Perhaps it simply wasn't interested in us after that one encounter. What it could have told us, if it wanted to! Hell and chyort vozmi! Damn – I'm talking Sasha's hated Russlish again. Let's change the subject.
   'I can't thank you too much for everything you've done, and for reporting on the situation at home. I feel slightly better about it now – having something even bigger to worry about is perhaps the best cure for any insoluble problem.
   'For the first time, I'm beginning to wonder if any of us will ever see Earth again.'

43 – Thought Experiment

   When one spends months with a small, isolated group of people, one becomes very sensitive to the moods and emotional states of all its members. Floyd was now aware of a subtle change in attitude toward him; its most obvious manifestation was the reappearance of the greeting 'Dr Floyd', which he had not heard for so long that he was often slow to respond to it.
   No one, he was sure, believed that he had really gone crazy; but the possibility was being considered. He did not resent that; indeed, he was grimly amused by it as he set about the task of proving his sanity.
   He did have some slight supporting evidence from Earth. José Fernandez still maintained that his wife had reported an encounter with David Bowman, while she continued to deny it and refused to speak to any of the news media. It was hard to see why poor José should have invented such a peculiar story, especially as Betty seemed a very stubborn and quick-tempered lady. From his hospital bed, her husband declared that he still loved her and theirs was only a temporary disagreement.
   Floyd hoped that Tanya's present coolness toward him was equally temporary. He was quite sure that she was as unhappy about it as he was, and he was certain that her attitude was not a matter of deliberate choice. Something had happened that simply would not fit into her pattern of beliefs, so she would try to avoid any reminders of it. Which meant having as little to do with Floyd as possible – a very unfortunate situation now that the most critical stage of the mission was fast approaching.
   It had not been easy to explain the logic of Tanya's operational plan to the waiting billions back on Earth – especially to the impatient television networks, which had grown tired of showing the same never-changing views of Big Brother. 'You've gone all this way, at enormous cost, and you just sit and watch the thing! Why don't you do something?' To all these critics Tanya had given the same answer: 'I will – just as soon as the launch window opens, so that we can leave immediately if there's any adverse reaction.'
   Plans for the final assault on Big Brother had already been worked out and agreed upon with Mission Control. Leonov would move in slowly, probing at all frequencies, and with steadily increasing power – constantly reporting back to Earth at every moment. When final contact was made, they would try to secure samples by drilling or laser spectroscopy; no one really expected these endeavours to succeed, as even after a decade of study TMA-1 resisted all attempts to analyse its material. The best efforts of human scientists in this direction seemed comparable to those of Stone Age men trying to break through the armour of a bank vault with flint axes.
   Finally, echo sounders and other seismic devices would be attached to the faces of Big Brother. A large collection of adhesives had been brought along for the purpose, and if they did not work – well, one could always fall back on a few kilometres of good, old-fashioned string, even though there seemed something faintly comic about the idea of wrapping up the Solar System's greatest mystery, as if it were a parcel about to be sent through the mail.
   Not until Leonov was well on the way home would small explosive charges be detonated, in the hope that the waves propagated through Big Brother would reveal something about its interior structure. This last measure had been hotly debated, both by those who argued that it would generate no results at all – and those who feared it would produce altogether too many.
   For a long time, Floyd had wavered between the two viewpoints; now the matter seemed only of trivial importance.
   The time for final contact with Big Brother – the great moment that should have been the climax of the expedition – was on the wrong side of the mysterious deadline. Heywood Floyd was convinced that it belonged to a future that would never exist; but he could get no one to agree with him.
   And that was the least of his problems. Even if they did agree, there was nothing that they could do about it.
   Walter Curnow was the last person he would have expected to resolve the dilemma. For Walter was almost the epitome of the sound, practical engineer, suspicious of flashes of brilliance and technological quick-fixes. No one would ever accuse him of being a genius; and sometimes it required genius to see the blindingly obvious.
   'Consider this purely as an intellectual exercise,' he had begun, with most uncharacteristic hesitancy. 'I'm quite prepared to be shot down.'
   'Go on,' answered Floyd. 'I'll hear you out politely. That's the least I can do – everyone's been very polite to me. Too polite, I'm afraid.'
   Curnow gave a lopsided grin.
   'Can you blame them? But if it's any consolation, at least three people now take you quite seriously, and are wondering what we should do.'
   'Does that three include you?'
   'No; I'm sitting on the fence, which is never terribly comfortable. But in case you're right – I don't want to wait here and take whatever's coming. I believe there's an answer to every problem, if you look in the right place.'
   'I'll be delighted to hear it. I've been looking hard enough. Presumably not in the right place.'
   'Perhaps. If we want to make a quick getaway – say in fifteen days, to beat that deadline – we'll need an extra delta-vee of about thirty kilometres a second.'
   'So Vasili calculates. I haven't bothered to check, but I'm sure he's right. After all, he got us here.'
   'And he could get us away – if we had the additional propellant.'
   'And if we had a Star Trek beam transporter, we could get back to Earth in an hour.'
   'I'll try and rig one up the next time I have a spare moment. But meanwhile, may I point out that we have several hundred tons of the best possible propellant, only a few metres away in Discovery's fuel tanks.'
   'We've been through that dozens of times. There's absolutely no way of transferring it to Leonov. We've no pipelines – no suitable pumps. And you can't carry liquid ammonia around in buckets, even in this part of the Solar System.'
   'Exactly. But there's no need to do so.'
   'Eh?'
   'Burn it right where it is. Use Discovery as a first stage, to boost us home.'
   If anyone except Walter Curnow had made the suggestion, Floyd would have laughed at him. As it was, his mouth dropped open and it was several seconds before he could think of a suitable comment. What finally emerged was: 'Damn. I should have thought of that.'
   Sasha was the first they approached. He listened patiently, pursed his lips, then played a rallentando on his computer keyboard. When the answers flashed up, he nodded thoughtfully.
   'You're right. It would give us the extra velocity we need to leave early. But there are practical problems -'
   'We know. Fastening the ships together. The off-axis thrust when only Discovery's drive is operating. Cutting loose again at the critical moment. But there are answers to all of these.'
   'I see you've been doing your homework. But it's a waste of time. You'll never convince Tanya.'
   'I don't expect to – at this stage,' Floyd answered. 'But I'd like her to know that the possibility exists. Will you give us moral support?'
   'I'm not sure. But I'll come along to watch; it should be interesting.'
   Tanya listened more patiently than Floyd had expected, but with distinct lack of enthusiasm. However, by the time he had finished, she showed what could only be called reluctant admiration.
   'Very ingenious, Heywood -,
   'Don't congratulate me. All the credit should go to Walter. Or the blame.'
   'I don't imagine there will be much of either; it can never be more than a – what did Einstein call that sort of thing? – "thought experiment". Oh, I suspect it would work – in theory, at least. But the risks! So many things could go wrong. I'd only be prepared to consider it if we had absolute and positive proof that we were in danger. And with all respect, Heywood, I see not the slightest evidence of that.'
   'Fair enough; but at least you now know that we have another option. Do you mind if we work out the practical details – just in case?'
   'Of course not – as long as it doesn't interfere with the preflight checkout. I don't mind admitting that the idea does intrigue me. But it's really a waste of time; there's no way I'd ever approve it. Unless David Bowman appeared to me personally.'
   'Would you even then, Tanya?'
   Captain Orlova smiled, but without much humour. 'You know, Heywood – I'm really not sure. He'd have to be very persuasive.'

44 – Vanishing Trick

   It was a fascinating game in which everyone joined – but only when off duty. Even Tanya contributed ideas to the 'thought experiment', as she continued to call it.
   Floyd was perfectly well aware that all the activity was generated not by fear of an unknown danger that only he took seriously, but by the delightful prospect of returning to Earth at least a month earlier than anyone had imagined. Whatever the motive, he was satisfied. He had done his best, and the rest was up to the Fates.
   There was one piece of luck, without which the whole project would have been stillborn. The short, stubby Leonov, designed to drill safely through the Jovian atmosphere during the braking manoeuvre, was less than half the length of Discovery and so could be neatly piggybacked on the larger vessel, And the midships antenna mount would provide an excellent anchor point – assuming that it was strong enough to take the strain of Leonov's weight while Discovery's drive was operating.
   Mission Control was sorely puzzled by some of the requests flashed back to Earth during the next few' days. Stress analyses of both ships, under peculiar loads; effects of off-axis thrusts; location of unusually strong or weak points in the hulls – these were only some of the more esoteric problems the perplexed engineers were asked to tackle. 'Has something gone wrong?' they inquired anxiously.
   'Not at all,' Tanya replied. 'We're merely investigating possible options. Thank you for your cooperation. End of transmission.'
   Meanwhile, the programme went ahead as planned. All systems were carefully checked in both ships, and readied for the separate voyages home; Vasili ran simulations on return trajectories and Chandra fed them to Hal when they had been debugged – getting Hal to make a final check in the process. And Tanya and Floyd worked amicably together orchestrating the approach to Big Brother like generals planning an invasion.
   It was what he had come all the way to do, yet Floyd's heart was no longer in it. He had undergone an experience he could share with no one – even those who believed him. Though he carried out his duties efficiently, much of the time his mind was elsewhere.
   Tanya understood perfectly.
   'You're still hoping for that miracle to convince me, aren't you?'
   'Or deconvince me – that would be equally acceptable. It's the uncertainty that I dislike.'
   'So do I. But it won't be much longer now – one way or the other.'
   She glanced briefly toward the situation display, where the figure 20 was slowly flashing. It was the most unnecessary bit of information in the entire ship, since everyone knew by heart the number of days until the launch window opened.
   And the assault on Zagadka was scheduled.
   For the second time, Heywood Floyd was looking the other way when it happened. But it would have made no difference in any case; even the vigilant monitor camera showed only a faint blur between one full frame and the subsequent blank one.
   Once more he was on duty aboard Discovery, sharing the graveyard shift with Sasha over on Leonov. As usual, the night had been totally uneventful; the automatic systems were performing their jobs with their normal efficiency. Floyd would never have believed, a year ago, that he would one day orbit Jupiter at a distance of a few hundred thousand kilometres and give it barely a glance – while trying; not very successfully, to read The Kreutzer Sonata in the original. According to Sasha, it was still the finest piece of erotic fiction in (respectable) Russian literature, but Floyd had not yet progressed far enough to prove that. And now he never would.
   At 0125 he was distracted by a spectacular, though not unusual, eruption on the terminator of Io. A vast umbrella-shaped cloud expanded into space, and started to shower its debris back on to the burning land below. Floyd had seen dozens of such eruptions, but they never ceased to fascinate him. It seemed incredible that so small a world could be the seat of such titanic energies.
   To get a better view, he moved around to one of the other observation windows. And what he saw there – or, rather, what he did not see there – made him forget about Io, and almost everything else.
   When he had recovered, and satisfied himself that he was not suffering – again? – from hallucinations, he called the other ship.
   'Good morning, Woody,' yawned Sasha. 'No – I wasn't asleep. How are you getting on with old Tolstoi?'
   'I'm not. Take a look outside and tell me what you see.'
   'Nothing unusual, for this part of the cosmos. Io doing its thing. Jupiter. Stars. Oh my God!'
   'Thanks for proving I'm sane. We'd better wake the skipper.'
   'Of course. And everyone else. Woody – I'm scared.'
   'You'd be a fool not to be. Here we go. Tanya? Tanya? Woody here. Sorry to wake you up – but your miracle's happened. Big Brother has gone. Yes – vanished. After three million years, he's decided to leave.
   'I think he must know something that we don't.'
   It was a sombre little group that gathered, during the next fifteen minutes, for a hasty conference in the wardroom-cum-observation lounge. Even those who had just gone to sleep were instantly awake, as they sipped thoughtfully from bulbs of hot coffee – and kept glancing at the shockingly unfamiliar scene outside Leonov's windows, to convince themselves that Big Brother had indeed vanished.
   'It must know something that we don't.' That spontaneous phrase of Floyd's had been repeated by Sasha and now hung silently, ominously, in the air. He had summed up what everyone was now thinking – even Tanya.
   It was still too early to say 'I told you so' – nor did it really matter whether that warning had any validity. Even if it was perfectly safe to stay, there was no point in doing so. With nothing to investigate, they might as well go home, just as quickly as possible. Yet it was not quite as simple as that.
   'Heywood,' said Tanya, 'I'm now prepared to take that message, or whatever it was, much more seriously. I'd be stupid not to after what's happened. But even if there is danger here, we still have to weigh one risk against another. Coupling Leonov and Discovery together, operating Discovery with that huge off-axis load, disconnecting the ships in a matter of minutes so we can fire our engines at the right moment; no responsible captain would take such chances without very good – I'd say overwhelming – reasons. Even now, I don't have such reasons. I've only got the word of ... a ghost. Not very good evidence in a court of law.'
   'Or a court of inquiry,' said Walter Curnow, in an unusually quiet voice, 'even if we all backed you up.'
   'Yes, Walter – I was thinking of that. But if we get home safely, that will justify everything – and if we don't, it hardly matters, does it? Anyway, I'm not going to decide now. As soon as we've reported this, I'm going back to bed. I'll give you my decision in the morning after I've slept on it. Heywood, Sasha, will you come up to the bridge with me? We have to wake up Mission Control, before you go back on watch.'
   The night had not yet finished with its surprises. Somewhere around the orbit of Mars, Tanya's brief report passed a message going in the opposite direction.
   Betty Fernandez had talked at last, Both the CIA and the National Security Agency were furious; their combined blandishments, appeals to patriotism, and veiled threats had failed completely – yet the producer of a sleazy gossip network had succeeded, thereby making himself immortal in the annals of Videodom.
   It was half luck, half inspiration. The news director of 'Hello, Earth!' had suddenly realized that one of his staff bore a striking likeness to David Bowman; a clever makeup artist had made it perfect. José Fernandez could have told the young man that he was taking a terrible risk, but he had the good fortune that often favours the brave. Once he had got his foot inside the door, Betty had capitulated. By the time she had – quite gently – thrown him out, he had obtained essentially the whole story. And to do him credit, he had presented it with a lack of leering cynicism quite uncharacteristic of his network. It got him that year's Pulitzer.
   'I wish,' Floyd said rather wearily to Sasha, 'she'd talked earlier. It would have saved me a lot of trouble. Anyway, that settles the argument. Tanya can't possibly have any doubts now. But we'll leave it until she wakes up – don't you agree?'
   'Of course – it's not urgent, even though it's certainly important. And she'll need the sleep. I have a feeling none of us will get much from now on.'
   I'm sure you're right, thought Floyd. He felt very tired, but even if he had not been on duty he would have found it impossible to sleep. His mind was too active, analysing the events of this extraordinary night, trying to anticipate the next surprise.
   In one way, he felt an enormous sense of relief: All uncertainty about their departure was surely ended; Tanya could have no further reservations.
   But a much greater uncertainty remained. What was happening?
   There was only one experience in Floyd's life that matched the situation. As a very young man, he had once gone canoeing with some friends down a tributary of the Colorado River – and they had lost their way.
   They had been swept faster and faster between the canyon walls, not completely helpless, but with only enough control to avoid being swamped. Ahead might be rapids – perhaps even a waterfall; they did not know. And in any case, there was little they could do about it.
   Once again, Floyd felt himself in the grip of irresistible forces, sweeping him and his companions toward an unknown destiny. And this time the dangers were not only invisible; they might be beyond human comprehension.