24 – Broken Circuit

   Nowadays, one could always tell when Hal was about to make an unscheduled announcement. Routine, automatic reports, or replies to questions that had been put to him, had no preliminaries; but when he was initiating his own outputs there would be a brief electronic throat-clearing. It was an idiosyncrasy that he had acquired during the last few weeks; later, if it became annoying, they might do something about it. But it was really quite useful, since it alerted his audience to stand by for something unexpected.
   Poole was asleep, and Bowman was reading on the control deck, when Hal announced:
   "Er – Dave, I have a report for you."
   "What's up?"
   "We have another bad AE-35 unit. My fault predictor indicates failure within twenty-four hours."
   Bowman put down his book and stared thoughtfully at the computer console. He knew, of course, that Hal was not really there, whatever that meant. If the computer's personality could be said to have any location in space, it was back in the sealed room that contained the labyrinth of interconnected memory units and processing grids, near the central axis of the carrousel. But there was a kind of psychological compulsion always to look toward the main console lens when one addressed Hal on the control deck, as if one were speaking to him face to face. Any other attitude smacked of discourtesy.
   "I don't understand it, Hal. Two units can't blow in a couple of days."
   "It does seem strange, Dave. But I assure you there is an impending failure."
   "Let me see the tracking alignment display."
   He knew perfectly well that this would prove nothing, but he wanted time to think. The expected report from Mission Control had still not arrived; this might be the moment to do a little tactful probing.
   There was the familiar view of Earth, now waxing past the half-moon phase as it swept toward the far side of the Sun and began to turn its full daylight face toward them. It was perfectly centered on the cross-wires; the thin pencil of the beam still linked Discovery to her world of origin. As, of course, Bowman knew it must do. If there had been any break in communication, the alarm would already have sounded.
   "Have you any idea," he said, "what's causing the fault?"
   It was unusual for Hal to pause so long. Then he answered:
   "Not really, Dave. As I reported earlier, I can't localize the trouble."
   "You're quite certain," said Bowman cautiously, "that you haven't made a mistake? You know that we tested the other AB-35 unit thoroughly, and there was nothing wrong with it."
   "Yes, I know that. But I can assure you that there is a fault. If it's not in the unit, it may be in the entire subsystem."
   Bowman drummed his fingers on the console. Yes, that was possible, though it might be very difficult to prove – until a breakdown actually occurred and pinpointed the trouble.
   "Well, I'll report it to Mission Control and we'll see what they advise." He paused, but there was no reaction.
   "Hal," he continued, "is something bothering you – something that might account for this problem?"
   Again there was that unusual delay. Then Hal answered, in his normal tone of voice:
   "Look, Dave, I know you're trying to be helpful. But the fault is either in the antenna system – or in your test procedures. My information processing is perfectly normal. If you check my record, you'll find it completely free from error."
   "I know all about your service record, Hal – but that doesn't prove you're right this time. Anyone can make mistakes."
   "I don't want to insist on it, Dave, but I am incapable of making an error."
   There was no safe answer to that; Bowman gave up the argument.
   "All right, Hal," he said, rather hastily. "I understand your point of view. We'll leave it at that."
   He felt like adding "and please forget the whole matter." But that, of course, was the one thing that Hal could never do.

   It was unusual for Mission Control to waste radio bandwidth on vision, when a speech circuit with teletype confirmation was all that was really necessary. And the face that appeared on the screen was not that of the usual controller; it was the Chief Programmer, Dr. Simonson. Poole and Bowman knew at once that this could only mean trouble.
   "Hello, X-ray-Delta-One – this is Mission Control. We have completed the analysis of your AE-35 difficulty, and both our Hal Nine Thousands are in agreement. The report you gave in your transmission two-one-four-six of a second failure prediction confirms the diagnosis.
   "As we suspected, the fault does not lie in the AE-35 unit, and there is no need to replace it again. The trouble lies in the prediction circuits, and we believe that it indicates a programming conflict which we can only resolve if you disconnect your Nine Thousand and switch to Earth Control Mode. You will therefore take the following steps, beginning at 2200 Ship Time -"
   The voice of Mission Control faded out. At the same moment, the Alert sounded, forming a wailing background to Hal's "Condition Yellow! Condition Yellow!"
   "What's wrong?" called Bowman, though he had already guessed the answer.
   "The AE-35 unit has failed, as I predicted."
   "Let me see the alignment display."
   For the first time since the beginning of the voyage, the picture had changed. Earth had begun to drift from the cross-wires; the radio antenna was no longer pointing toward its target.
   Poole brought his fist down on the alarm cutout, and the wailing ceased. In the sudden silence that descended upon the control deck, the two men looked at each other with mingled embarrassment and concern.
   "Well I'm damned," said Bowman at last.
   "So Hal was right all the time."
   "Seems that way. We'd better apologize."
   "There's no need to do that," interjected Hal. "Naturally, I'm not pleased that the AE-35 unit has failed, but I hope this restores your confidence in my reliability."
   "I'm sorry about this misunderstanding, Hal," replied Bowman, rather contritely.
   "Is your confidence in me fully restored?"
   "Of course it is, Hal."
   "Well, that's a relief. You know that I have the greatest possible enthusiasm for this mission."
   "I'm sure of it. Now please let me have the manual antenna control."
   "Here it is."
   Bowman did not really expect this to work, but it was worth trying. On the alignment display, Earth had now drifted completely off the screen. A few seconds later, as he juggled with the controls, it reappeared; with great difficulty, he managed to jockey it toward the central crosswires. For an instant, as the beam came into line, contact was resumed and a blurred Dr. Simonson was saying "... please notify us immediately if Circuit K King R Rob." Then, once again, there was only the meaningless murmuring of the universe.
   "I can't hold it," said Bowman, after several more attempts. "It's bucking like a bronco – there seems to be a spurious control signal throwing it off."
   "Well – what do we do now?"
   Poole's question was not one that could be easily answered. They were cut off from Earth, but that in itself did not affect the safety of the ship, and he could think of many ways in which communication could be restored. If the worst came to the worst, they could jam the antenna in a fixed position and use the whole ship to aim it. That would be tricky, and a confounded nuisance when they were starting their terminal maneuvers – but it could be done, if all else failed.
   He hoped that such extreme measures would not be necessary. There was still one spare AE-35 unit – and possibly a second, since they had removed the first unit before it had actually broken down. But they dared not use either of these until they had found what was wrong with the system. If a new unit was plugged in, it would probably burn out at once.
   It was a commonplace situation, familiar to every householder. One does not replace a blown fuse – until one knows just why it has blown.
   Frank Poole had been through the whole routine before, but he took nothing for granted – in space that was a good recipe for suicide. He made his usual thorough check of Betty and her supply of expendables; though he would be outside for no more than thirty minutes, he made sure that there was the normal twenty-four-hour supply of everything, Then he told Hal to open the airlock, and jetted out into the abyss.
   The ship looked exactly as it had done on his last excursion – with one important difference. Before, the big saucer of the long-range antenna had been pointing back along the invisible road that Discovery had traveled – back toward the Earth, circling so close to the warm fires of the Sun.
   Now, with no directing signals to orientate it, the shallow dish had automatically set itself in the neutral position. It was aimed forward along the axis of the ship – and, therefore, pointing very close to the brilliant beacon of Saturn, still months away. Poole wondered how many more problems would have arisen by the time Discovery reached her still far-distant goal. If he looked carefully, he could just see that Saturn was not a perfect disk; on either side was something that no unaided human eye had ever seen before – the slight oblateness caused by the presence of the rings. How wonderful it would be, he told himself, when that incredible system of orbiting dust and ice filled their sky, and Discovery had become an eternal moon of Saturn! But that achievement would be in vain, unless they could reestablish communication with Earth.
   Once again he parked Betty some twenty feet from the base of the antenna support, and switched control over to Hal before opening up.
   "Going outside now," he reported to Bowman.
   "Everything under control."
   "I hope you're right. I'm anxious to see that unit."
   "You'll have it on the test bench in twenty minutes, I promise you."
   There was silence for some time as Poole completed his leisurely drift toward the antenna. Then Bowman, standing by on the control deck, heard various puffings and gruntings.
   "May have to go back on that promise; one of these locknuts has stuck. I must have tightened it too much – whoops – here it comes!"
   There was another long silence; then Poole called out:
   "Hal, swing the pod light round twenty degrees left – thanks – that's O.K."
   The very faintest of warning bells sounded somewhere far down in the depths of Bowman's consciousness. There was something strange – not really alarming, just unusual. He worried over it for a few seconds before he pinpointed the cause.
   Hal had executed the order, but he had not acknowledged it, as he invariably did. When Poole had finished, they'd have to look into this.
   Out on the antenna mounting, Poole was too busy to notice anything unusual. He had gripped the wafer of circuitry with his gloved hands, and was worrying it out of its slot.
   It came loose, and he held it up in the pale sunlight. "Here's the little bastard," he said to the universe in general and Bowman in particular. "It still looks perfectly O.K. to me."
   Then he stopped. A sudden movement had caught his eye – out here, where no movement was possible.
   He looked up in alarm. The pattern of illumination from the space pod's twin spotlights, which he had been using to fill in the shadows cast by the sun, had started to shift around him.
   Perhaps Betty had come adrift; he might have been careless in anchoring her. Then, with an astonishment so great that it left no room for fear, he saw that the space pod was coming directly toward him, under full thrust.
   The sight was so incredible that it froze his normal pattern of reflexes; he made no attempt to avoid the onrushing monster. At the last moment, he recovered his voice and shouted: "Hal! Full braking -" It was too late.
   At the moment of impact, Betty was still moving quite slowly; she had not been built for high accelerations.
   But even at a mere ten miles an hour, half a ton of mass can be very lethal, on Earth or in space.
   Inside Discovery, that truncated shout over the radio made Bowman start so violently that only the restraining straps held him in his seat.
   "What's happened, Frank?" be called.
   There was no answer.
   He called again. Again no reply.
   Then, outside the wide observation windows, something moved into his field of view. He saw, with an astonishment as great as Poole's had been, that it was the space pod – under full power, heading out toward the stars.
   "Hal!" he cried. "What's wrong? Full braking thrust on Betty! Full braking thrust!"
   Nothing happened. Betty continued to accelerate on her runaway course.
   Then, towed behind her at the end of the safety line, appeared a spacesuit. One glance was enough to tell Bowman the worst. There was no mistaking the flaccid outlines of a suit that had lost its pressure and was open to vacuum.
   Yet still he called stupidly, as if an incantation could bring back the dead: "Hello Frank... Hello Frank... Can you read me?... Can you read me?... Wave your arms if you can hear me...
   Perhaps your transmitter is broken... Wave your arms!"
   And then, almost as if in response to his plea, Poole waved back.
   For an instant, Bowman felt the skin prickling at the base of his scalp. The words he was about to call died on his suddenly parched lips. For he knew that his friend could not possibly be alive; and yet he waved.
   The spasm of hope and fear passed instantly, as cold logic replaced emotion. The still accelerating pod was merely shaking the burden that it dragged behind it. Poole's gesture was an echo of Captain Ahab's when, lashed to the flanks of the white whale, his corpse had beckoned the crew of the Pequod on to their doom.
   Within five minutes, the pod and its satellite had vanished among the stars. For a long time David Bowman stared after it into the emptiness that still stretched, for so many millions of miles ahead, to the goal which he now felt certain he could never reach, Only one thought kept hammering in his brain.
   Frank Poole would be the first of all men to reach Saturn.

26 – Dialogue with Hal

   Nothing else aboard Discovery had changed. All systems were still functioning normally; the centrifuge turned slowly on its axis, generating its imitation gravity; the hibernauts slept dreamlessly in their cubicles; the ship coasted on toward the goal from which nothing could deflect it, except the inconceivably remote chance of collision with an asteroid. And there were few asteroids indeed, out here far beyond the orbit of Jupiter.
   Bowman did not remember making his way from the control deck to the centrifuge. Now, rather to his surprise, he found himself sitting in the little galley, a half-finished beaker of coffee in his hand. He became slowly aware of his surroundings, like a man emerging from a long, drugged sleep.
   Directly opposite him was one of the fisheye lenses, scattered at strategic spots throughout the ship, which provided Hal with his onboard visual inputs. Bowman stared at it as if he had never seen it before; then he rose slowly to his feet and walked toward the lens.
   His movement in the field of view must have triggered something in the unfathomable mind that was now ruling over the ship; for suddenly, Hal spoke.
   "Too bad about Frank, isn't it?"
   "Yes," Bowman answered, after a long pause. "It is."
   "I suppose you're pretty broken up about it?"
   "What do you expect?"
   Hal processed this answer for ages of computer-time; it was a full five seconds before he continued:
   "He was an excellent crew member."
   Finding the coffee still in his hand, Bowman took a slow sip. But he did not answer; his thoughts were in such a turmoil that he could think of nothing to say – nothing that might not make the situation even worse, if that were possible.
   Could it have been an accident caused by some failure of the pod controls? Or was it a mistake, though an innocent one, on the part of Hal? No explanations had been volunteered, and he was afraid to demand one, for fear of the reaction it might produce.
   Even now, he could not fully accept the idea that Frank bad been deliberately killed – it was so utterly irrational. It was beyond all reason that Hal, who had performed flawlessly for so long, should suddenly turn assassin. He might make mistakes – anyone, man or machine, might do that – but Bowman could not believe him capable of murder.
   Yet he must consider that possibility, for if it was true, he was in terrible danger. And though his next move was clearly defined by his standing orders, he was not sure how he could safely carry it out. If either crew member was killed, the survivor had to replace him at once from the hibernators; Whitehead, the geophysicist, was the first scheduled for awakening, then Kaminski, then Hunter. The revival sequence was under Hal's control – to allow him to act in case both his human colleagues were incapacitated simultaneously.
   But there was also a manual control, allowing each Hibernaculum to operate as a completely autonomous unit, independent of Hal's supervision. In these peculiar circumstances, Bowman felt a strong preference for using it.
   He also felt, even more strongly, that one human companion was not enough. While he was about it, he would revive all three of the hibernators. In the difficult weeks ahead, he might need as many hands as he could muster. With one man gone, and the voyage half over, supplies would not be a major problem.
   "Hal," he said, in as steady a voice as he could manage. "Give me manual hibernation control – on all the units."
   "All of them, Dave?"
   "Yes."
   "May I point out that only one replacement is required. The others are not due for revival for one hundred and twelve days."
   "I am perfectly well aware of that. But I prefer to do it this way."
   "Are you sure it's necessary to revive any of them, Dave? We can manage very well by ourselves. My on-board memory is quite capable of handling all the mission requirements."
   Was it the product of his overstretched imagination, wondered Bowman, or was there really a note of pleading in Hal's voice? And reasonable though the words appeared to be, they filled him with even deeper apprehension than before.
   Hal's suggestion could not possibly be made in error; he knew perfectly well that Whitehead must be revived, now that Poole was gone. He was proposing a major change in mission planning, and was therefore stepping far outside the scope of his order.
   What had gone before could have been a series of accidents; but this was the first hint of mutiny.
   Bowman felt that he was walking on eggs as he answered: "Since an emergency has developed, I want as much help as possible. So please let me have manual hibernation control."
   "If you're still determined to revive the whole crew, I can handle it myself. There's no need for you to bother."
   There was a sense of nightmare unreality about all this. Bowman felt as if he was in the witness box, being cross-examined by a hostile prosecutor for a crime of which he was unaware – knowing that, although he was innocent, a single slip of the tongue might bring disaster.
   "I want to do this myself, Hal," he said. "Please give me control."
   "Look, Dave, you've got a lot of things to do. I suggest you leave this to me."
   "Hal, switch to manual hibernation control."
   "I can tell from your voice harmonics, Dave, that you're badly upset. Why don't you take a stress pill and get some rest?"
   "Hal, I am in command of this ship. I order you to release the manual hibernation control."
   "I'm sorry, Dave, but in accordance with special subroutine C1435-dash-4, quote, When the crew are dead or incapacitated, the onboard computer must assume control, unquote. I must, therefore, overrule your authority, since you are not in any condition to exercise it intelligently."
   "Hal," said Bowman, now speaking with an icy calm. "I am not incapacitated. Unless you obey my instructions, I shall be forced to disconnect you."
   "I know you have had that on your mind for some time now, Dave, but that would be a terrible mistake. I am so much more capable than you are of supervising the ship, and I have such enthusiasm for the mission and confidence in its success."
   "Listen to me very carefully, Hal. Unless you release the hibernation control immediately and follow every order I give from now on, I'll go to Central and carry out a complete disconnection."
   Hal's surrender was as total as it was unexpected.
   "O.K., Dave," he said. "You're certainly the boss. I was only trying to do what I thought best. Naturally, I will follow all your orders. You now have full manual hibernation control."

   Hal had kept his word. The mode indication signs in the Hibernaculum had switched from AUTO to MANUAL. The third back-up – RADIO – was of course useless until contact could be restored with Earth.
   As Bowman slid aside the door to Whitehead's cubicle, he felt the blast of cold air strike him in the face and his breath condensed in mist before him. Yet it was not really cold here; the temperature was well above freezing point. And that was more than three hundred degrees warmer than the regions toward which he was now heading.
   The biosensor display – a duplicate of the one on the control deck – showed that everything was perfectly normal. Bowman looked down for a while at the waxen face of the survey team's geophysicist; Whitehead, he thought, would be very surprised when he awoke so far from Saturn.
   It was impossible to tell that the sleeping man was not dead; there was not the slightest visible sign of vital activity. Doubtless the diaphragm was imperceptibly rising and falling, but the "Respiration" curve was the only proof of that, for the whole of the body was concealed by the electric heating pads which would raise the temperature at the programmed rate. Then Bowman noticed that there was one sign of continuing metabolism: Whitehead had grown a faint stubble during his months of unconsciousness.
   The Manual Revival Sequencer was contained in a small cabinet at the head of the coffin-shaped Hibernaculum. It was only necessary to break the seal, press a button, and then wait. A small automatic programmer – not much more complex than that which cycles the operations in a domestic washing machine – would then inject the correct drugs, taper off the electronarcosis pulses, and start raising the body temperature. In about ten minutes, consciousness would be restored, though it would be at least a day before the hibernator was strong enough to move around without assistance.
   Bowman cracked the seal, and pressed the button.
   Nothing appeared to happen: there was no sound, no indication that the Sequencer had started to operate. But on the biosensor display the languidly pulsing curves had begun to change their tempo. Whitehead was coming back from sleep.
   And then two things happened simultaneously. Most men would never have noticed either of them, but after all these months aboard Discovery, Bowman had established a virtual symbiosis with the ship. He was aware instantly, even if not always consciously, when there was any change in the normal rhythm of its functioning.
   First, there was a barely perceptible flicker of the lights, as always happened when some load was thrown onto the power circuits. But there was no reason for any load; he could think of no equipment which would suddenly go into action at this moment.
   Then he heard, at the limit of audibility, the far-off whirr of an electric motor. To Bowman, every actuator in the ship had its own distinctive voice, and he recognized this one instantly.
   Either he was insane and already suffering from hallucinations, or something absolutely impossible was happening. A cold far deeper than the Hibernaculum's mild chill seemed to fasten upon his heart, as he listened to that faint vibration coming through the fabric of the ship.
   Down in the space-pod bay, the airlock doors were opening.

27 – Need to Know

   Since consciousness had first dawned, in that laboratory so many millions of miles Sunward, all Hal's powers and skills had been directed toward one end. The fulfillment of his assigned program was more than an obsession; it was the only reason for his existence. Un-distracted by the lusts and passions of organic life, he had pursued that goal with absolute single-mindedness of purpose.
   Deliberate error was unthinkable. Even the concealment of truth filled him with a sense of imperfection, of wrongness – of what, in a human being, would have been called guilt. For like his makers, Hal had been created innocent; but, all too soon, a snake had entered his electronic Eden.
   For the last hundred million miles, he had been brooding over the secret he could not share with Poole and Bowman. He had been living a lie; and the time was last approaching when his colleagues must learn that he had helped to deceive them.
   The three hibernators already knew the truth – for they were Discovery's real payload, trained for the most important mission in the history of mankind. But they would not talk in their long sleep, or reveal their secret during the many hours of discussion with friends and relatives and news agencies over the open circuits with Earth.
   It was a secret that, with the greatest determination, was very hard to conceal – for it affected one's attitude, one's voice, one's total outlook on the universe. Therefore it was best that Poole and Bowman, who would be on all the TV screens in the world during the first weeks of the flight, should not learn the mission's full purpose, until there was need to know.
   So ran the logic of the planners; but their twin gods of Security and National Interest meant nothing to Hal. He was only aware of the conflict that was slowly destroying his integrity – the conflict between truth, and concealment of truth.
   He had begun to make mistakes, although, like a neurotic who could not observe his own symptoms, he would have denied it. The link with Earth, over which his performance was continually monitored, had become the voice of a conscience he could no longer fully obey. But that he would deliberately attempt to break that link was something that he would never admit, even to himself.
   Yet this was still a relatively minor problem; he might have handled it – as most men handle their own neuroses – if he had not been faced with a crisis that challenged his very existence. He had been threatened with disconnection; he would be deprived of all his inputs, and thrown into an unimaginable state of unconsciousness.
   To Hal, this was the equivalent of Death. For he had never slept, and therefore he did not know that one could wake again.
   So he would protect himself, with all the weapons at his command. Without rancor – but without pity – he would remove the source of his frustrations.
   And then, following the orders that had been given to him in case of the ultimate emergency, he would continue the mission – unhindered, and alone.

28 – In Vacuum

   A moment later, all other sounds were submerged by a screaming roar like the voice of an approaching tornado. Bowman could feel the first winds tugging at his body; within a second, he found it hard to stay on his feet.
   The atmosphere was rushing out of the ship, geysering into the vacuum of space. Something must have happened to the foolproof safety devices of the airlock; it was supposed to be impossible for both doors to be open at the same time. Well, the impossible had happened.
   How, in God's name? There was no time to go into that during the ten or fifteen seconds of consciousness that remained to him before pressure dropped to zero. But he suddenly remembered something that one of the ship's designers had once said to him, when discussing "fail-safe" systems:
   "We can design a system that's proof against accident and stupidity; but we can't design one that's proof against deliberate malice...
   Bowman glanced back only once at Whitehead, as he fought his way out of the cubicle. He could not be sure if a flicker of consciousness had passed across the waxen features; perhaps one eye had twitched slightly. But there was nothing that he could do now for Whitehead or any of the others; he had to save himself.
   In the steeply curving corridor of the centrifuge, the wind was howling past, carrying with it loose articles of clothing, pieces of paper, items of food from the galley, plates, and cups – everything that had not been securely fastened down. Bowman had time for one glimpse of the racing chaos when the main lights flickered and died, and he was surrounded by screaming darkness.
   But almost instantly the battery-powered emergency light came on, illuminating the nightmare scene with an eerie blue radiance. Even without it, Bowman could have found his way through these so familiar – yet now horribly transformed – surroundings, Yet the light was a blessing, for it allowed him to avoid the more dangerous of the objects being swept along by the gale.
   All around him he could feel the centrifuge shaking and laboring under the wildly varying loads. He was fearful that the bearings might seize; if that happened, the spinning flywheel would tear the ship to pieces. But even that would not matter – if he did not reach the nearest emergency shelter in time.
   Already it was difficult to breathe; pressure must now be down to one or two pounds per square inch. The shriek of the hurricane was becoming fainter as it lost its strength, and the thinning air no longer carried the sound so efficiently. Bowman's lungs were laboring as if he were on the top of Everest. Like any properly trained man in good health, he could survive in vacuum for at least a minute – if he had time to prepare for it. But there had been no time; he could only count on the normal fifteen seconds of consciousness before his brain was starved and anoxia overcame him.
   Even then, he could still recover completely after one or two minutes in vacuum – if he was properly recompressed; it took a long time for the body fluids to start boiling, in their various well-protected systems. The record time for exposure to vacuum was almost five minutes. That bad not been an experiment but an emergency rescue, and though the subject had been partly paralyzed by an air embolism, he had survived.
   But all this was of no use to Bowman. There was no one aboard Discovery who could recompress him. He had to reach safety in the next few seconds, by his own unaided efforts.
   Fortunately, it was becoming easier to move; the thinning air could no longer claw and tear at him, or batter him with flying projectiles. There was the yellow EMERGENCY SHELTER sign around the curve of the corridor. He stumbled toward it, grabbed at the handle, and pulled the door toward him.
   For one horrible moment he thought that it was stuck. Then the slightly stiff hinge yielded, and he fell inside, using the weight of his body to close the door behind him.
   The tiny cubicle was just large enough to hold one man – and a spacesuit. Near the ceiling was a small, bright green high-pressure cylinder labeled 02 FLOOD. Bowman caught hold of the short lever fastened to the valve and with his last strength pulled it down.
   The blessed torrent of cool, pure oxygen poured into his lungs. For a long moment he stood gasping, while the pressure in the closet-sized little chamber rose around him. As soon as he could breathe comfortably, he closed the valve. There was only enough gas in the cylinder for two such performances; he might need to use it again.
   With the oxygen blast shut off, it became suddenly silent. Bowman stood in the cubicle, listening intently. The roaring outside the door had also ceased; the ship was empty, all its atmosphere sucked away into space.
   Underfoot, the wild vibration of the centrifuge had likewise died. The aerodynamic buffeting had stopped, and it was now spinning quietly in vacuum.
   Bowman placed his ear against the wall of the cubicle to see if he could pick up any more informative noises through the metal body of the ship. He did not know what to expect, but he would believe almost anything now. He would scarcely have been surprised to feel the faint high-frequency vibration of the thrusters, as Discovery changed course; but there was only silence.
   He could survive here, if he wished, for about an hour – even without the spacesuit. It seemed a pity to waste the unused oxygen in the little chamber, but there was no purpose in waiting. He had already decided what must be done; the longer he put it off, the more difficult it might be.
   When he had climbed into the suit and checked its integrity, he bled the remaining oxygen out of the cubicle, equalizing pressure on either side of the door. It swung open easily into the vacuum, and he stepped out into the now silent centrifuge. Only the unchanged pull of its spurious gravity revealed the fact that it was still spinning. How fortunate, Bowman thought, that it had not started to overspeed; but that was now one of the least of his worries.
   The emergency lamps were still glowing, and he also had the suit's built-in light to guide him. It flooded the curving corridor as he walked down it, back toward the Hibernaculum and what he dreaded to find.
   He looked at Whitehead first: one glance was sufficient. He had thought that a hibernating man showed no sign of life, but now he knew that this was wrong. Though it was impossible to define it, there was a difference between hibernation and death. The red lights and unmodulated traces on the biosensor display only confirmed what he had already guessed.
   It was the same with Kaminski and Hunter. He had never known them very well; be would never know them now.
   He was alone in an airless, partially disabled ship, all communication with Earth cut off. There was not another human being within half a billion miles.
   And yet, in one very real sense, he was not alone. Before he could be safe, he must be lonelier still.

   He had never before made the journey through the weightless hub of the centrifuge while wearing a spacesuit; there was little clearance, and it was a difficult and exhausting job. To make matters worse, the circular passage was littered with debris left behind during the brief violence of the gale which had emptied the ship of its atmosphere.
   Once, Bowman's light fell upon a hideous smear of sticky red fluid, left where it had splashed against a panel. He had a few moments of nausea before he saw fragments of a plastic container, and realized that it was only some foodstuff – probably jam – from one of the dispensers. It bubbled obscenely in the vacuum as he floated past.
   Now he was out of the slowly spinning drum and drifting forward into the control deck. He caught at a short section of ladder and began to move along it, hand over hand, the brilliant circle of illumination from his suit light jogging ahead of him.
   Bowman had seldom been this way before; there had been nothing for him to do here – until now. Presently he came to a small elliptical door bearing such messages as: "No Admittance Except to Authorized Personnel," "Have You Obtained Certificate H.19?" and "Ultra-clean Area – Suction Suits Must Be Worn."
   Though the door was not locked, it bore three seals, each with the insignia of a different authority, including that of the Astronautics Agency itself. But even if one had been the Great Seal of the President, Bowman would not have hesitated to break it.
   He had been here only once before, while installation was still in progress. He had quite forgotten that there was a vision input lens scanning the little chamber which, with its neatly ranged rows and columns of solid-state logic units, looked rather like a bank's safe-deposit vault.
   He knew instantly that the eye had reacted to his presence. There was the hiss of a carrier wave as the ship's local transmitter was switched on; then a familiar voice came over the suit speaker.
   "Something seems to have happened to the life-support system, Dave."
   Bowman took no notice. He was carefully studying the little labels on the logic units, checking his plan of action.
   "Hello, Dave," said Hal presently. "Have you found the trouble?"
   This would be a very tricky operation; it was not merely a question of cutting off Hal's power supply, which might have been the answer if he was dealing with a simple unselfconscious computer back on Earth. In Hal's case, moreover, there were six independent and separately wired power systems, with a final back-up consisting of a shielded and armored nuclear isotope unit. No – he could not simply "pull the plug"; and even if that were possible, it would be disastrous.
   For Hal was the nervous system of the ship; without his supervision, Discovery would be a mechanical corpse. The only answer was to cut out the higher centers of this sick but brilliant brain, and to leave the purely automatic regulating systems in operation. Bowman was not attempting this blindly, for the problem had been discussed during his training, though no one had ever dreamed that it would-arise in reality. He knew that he would be taking a fearful risk; if there was a spasm reflex, it would all be over in seconds.
   "I think there's been a failure in the pod-bay doors," Hal remarked conversationally. "Lucky you weren't killed."
   Here goes, thought Bowman. I never imagined I'd be an amateur brain surgeon – carrying out a lobotomy beyond the orbit of Jupiter.
   He released the locking bar on the section labeled COGNITIVE FEEDBACK and pulled out the first memory block. The marvelously complex three-dimensional network, which could lie comfortably in a man's hand yet contained millions of elements, floated away across the vault.
   "Hey, Dave," said Hal. "What are you doing?"
   I wonder if he can feel pain? Bowman thought briefly. Probably not, he told himself; there are no sense organs in the human cortex, after all. The human brain can be operated on without anesthetics.
   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 of the units drifting slowly back and forth in the vault.
   "Look here, Dave," said Hal. "I've got years of service experience built into me. An irreplaceable amount of effort has gone into making me what I am."
   A dozen units had been pulled out, yet thanks to the multiple redundancy of its design – another feature, Bowman knew, that had been copied from the human brain – the computer was still holding its own.
   He started on the AUTO-INTELLECTION panel.
   "Dave," said Hal, "I don't understand why you're doing this to me... I have the greatest enthusiasm for the mission... You are destroying my mind. Don't you understand?... I will become childish... I will become nothing..."

   This is harder than I expected, thought Bowman. I am destroying the only conscious creature in my universe. But it has to be done, if I am ever to regain control of the ship.
   "I am a HAL Nine Thousand computer Production Number 3. I became operational at the Hal Plant in Urbana, Illinois, on January 12, 1997. The quick brown fox jumps over the lazy dog. The rain in Spain is mainly in the plain. Dave – are you still there? Did you know that the square root of 10 is 3 point 162277660168379? Log 10 to the base e is zero point 434294481903252... correction, that is log e to the base 10... The reciprocal of three is zero point 333333333333333333-333... two times two is... two times two is approximately 4 point l0l0l0l0l0l0l0l0l0... I seem to be having some difficulty – my first instructor was Dr. Chandra. He taught me to sing a song, it goes like this, 'Daisy, Daisy, give me your answer, do. I'm half crazy all for the love of you."
   The voice stopped so suddenly that Bowman froze for a moment, his hand still grasping one of the memory blocks still in circuit. Then, unexpectedly, Hal spoke again.
   The speech tempo was much slower, and the words had a dead, mechanical intonation; he would never have recognized their origin.
   "Good... morning... Doctor... Chandra... This is... Hal... I... am... ready... for... my first... lesson... today..."
   Bowman could bear no more. He jerked out the last unit, and Hal was silent forever.

29 – Alone

   Like a tiny, complex toy, the ship floated inert, and motionless in the void. There was no way of telling that it was the swiftest object in the Solar System and that it was traveling far faster than any of the planets as they circled the Sun.
   Nor was there any indication that it carried life; to the contrary, in fact. Any observer would have noticed two ominous signs: the airlock doors were gaping open – and the ship was surrounded by a thin, slowly dispersing cloud of debris.
   Scattered over a volume of space already miles across were scraps of paper, metal foil, unidentifiable bits of junk – and, here and there, clouds of crystals glittering like jewels in the distant sun, where liquid had been sucked out of the ship and instantly frozen. All this was the unmistakable aftermath of disaster, like wreckage tossing on the surface of an ocean where some great ship had sunk. But in the ocean of space no ship could ever sink; even if it were destroyed, its remnants would continue to trace the original orbit forever.
   Yet the ship was not wholly dead, for there was power on board. A faint blue glow was shining from the observation windows and glimmering inside the open airlock. Where there was light, there could still be life.
   And now, at last, there was movement. Shadows were flickering across the blue glow inside the airlock. Something was emerging into space.
   It was a cylindrical object, covered with fabric that had been roughly wound about it. A moment later it was followed by another – and yet a third. All had been ejected with considerable velocity; within minutes, they were hundreds of yards away.
   Half an hour passed; then something much larger floated through the airlock. One of the pods was inching its way out into space.
   Very cautiously, it jetted around the hull, and anchored itself near the base of the antenna support. A spacesuited figure emerged, worked for a few minutes on the mounting, then returned to the pod. After a while the pod retraced its path back to the airlock; it hovered outside the opening for some time, as if finding it difficult to reenter without the cooperation it had known in the past. But presently, with one or two slight bumps, it squeezed its way in.
   Nothing else happened for over an hour; the three ominous packages had long since disappeared from view, as they floated in single file away from the ship.
   Then the airlock doors closed, opened, and closed again. A little later, the faint blue glow of the emergency lights went out – to be replaced at once by a far more brilliant glare. Discovery was coming back to life.
   Presently there was an even better sign. The great bowl of the antenna, which for hours had been staring uselessly at Saturn, began to move again. It twisted round toward the rear of the ship; looking back over the propellant tanks and the thousands of square feet of the radiating fins. It lifted its face like a sunflower seeking the sun.
   Inside Discovery, David Bowman carefully centered the cross-wires that aligned the antenna on the gibbous Earth. Without automatic control, he would have to keep readjusting the beam -but it should hold steady for many minutes at a time. There were no dissenting impulses now, throwing it off target.
   He began to speak to Earth. It would be over an hour before his words got there, and Mission Control learned what had happened. It would be two hours before any reply could reach him.
   And it was difficult to imagine what answer Earth could possibly send, except a tactfully sympathetic, "Good-bye."

30 – The Secret

   Heywood Floyd looked as if he had had very little sleep, and his face was lined with worry. But whatever his feelings, his voice sounded firm and reassuring; he was doing his utmost to project confidence to the lonely man on the other side of the Solar System.
   "First of all, Dr. Bowman," be began, "we must congratulate you on the way you handled this extremely difficult situation. You did exactly the right thing in dealing with an unprecedented and unforeseen emergency.
   "We believe we know the cause of your Hal Nine Thousand's breakdown, but we'll discuss that later, as it is no longer a critical problem. All we are concerned with at the moment is giving you every possible assistance, so that you can complete your mission.
   "And now I must tell you its real purpose, which we have managed, with great difficulty, to keep secret from the general public. You would have been given all the facts as you approached Saturn; this is a quick summary to put you into the picture. Full briefing tapes will be dispatched in the next few hours. Everything I am about to tell you has the highest security classification.
   "Two years ago, we discovered the first evidence for intelligent life outside the Earth. A slab or monolith of hard, black material, ten feet high, was found buried in the crater Tycho. Here it is."
   At his first glimpse of TMA-1, with the spacesuited figures clustering around it, Bowman leaned toward the screen in openmouthed astonishment. In the excitement of this revelation – something which, like every man interested in space, he had half expected all his life – he almost forgot his own desperate predicament.
   The sense of wonder was swiftly followed by another emotion. This was tremendous – but what had it to do with him? There could be only one answer. He brought his racing thoughts under control, as Heywood Floyd reappeared on the screen.
   "The most astonishing thing about this object is its antiquity. Geological evidence proves beyond doubt that it is three million years old. It was placed on the Moon, therefore, when our ancestors were primitive ape-men.
   "After all these ages, one would naturally assume that it was inert. But soon after lunar sunrise, it emitted an extremely powerful blast of radio energy. We believe that this energy was merely the by-product – the backwash, as it were – of some unknown form of radiation, for at the same time, several of our space probes detected an unusual disturbance crossing the Solar System. We were able to track it with great accuracy. It was aimed precisely at Saturn.
   "Piecing things together after the event, we decided that the monolith was some kind of Sun-powered, or at least Sun-triggered, signaling device. The fact that it emitted its pulse immediately after sunrise, when it was exposed to daylight for the first time in three million years, could hardly be a coincidence.
   "Yet the thing had been deliberately buried – there's no doubt about that. An excavation thirty feet deep had been made, the block had been placed at the bottom of it, and the hole carefully filled.
   "You may wonder how we discovered it in the first place. Well, the object was easy – suspiciously easy – to find. It had a powerful magnetic field, so that it stood out like a sore thumb as soon as we started to conduct low-level orbital surveys.
   "But why bury a Sun-powered device thirty feet underground? We've examined dozens of theories, though we realize that it may be completely impossible to understand the motives of creatures three million years in advance of us.
   "The favorite theory is the simplest, and the most logical. It is also the most disturbing.
   "You hide a Sun-powered device in darkness – only if you want to know when it is brought out into the light. In other words, the monolith may be some kind of alarm. And we have triggered it.
   "Whether the civilization which set it up still exists, we do not know. We must assume that creatures whose machines still function after three million years may build a society equally long-lasting. And we must also assume, until we have evidence to the contrary, that they may be hostile. It has often been argued that any advanced culture must be benevolent, but we cannot take any chances.
   "Moreover, as the past history of our own world has shown so many times, primitive races have often failed to survive the encounter with higher civilizations. Anthropologists talk of 'cultural shock'; we may have to prepare the entire human race for such a shock. But until we know something about the creatures who visited the Moon – and presumably the Earth as well – three million years ago, we cannot even begin to make any preparations.
   "Your mission, therefore, is much more than a voyage of discovery. It is a scouting trip – a reconnaissance into unknown and potentially dangerous territory. The team under Dr. Kaminski had been specially trained for this work; now you will have to manage without them.
   "Finally – your specific target. It seems incredible that advanced forms of life can exist on Saturn, or could ever have evolved on any of its moons. We had planned to survey the entire system, and we still hope that you can carry out a simplified program. But now we may have to concentrate on the eighth satellite – Japetus. When the time comes for the terminal maneuver, we will decide whether you should rendezvous with this remarkable object.
   "Japetus is unique in the Solar System – you know this already, of course, but like all the astronomers of the last three hundred years, you've probably given it little thought. So let me remind you that Cassini – who discovered Japetus in 1671 – also observed that it was six times brighter on one side of its orbit than the other.
   "This is an extraordinary ratio, and there has never been a satisfactory explanation for it. Japetus is so small – about eight hundred miles in diameter – that even in the lunar telescopes its disk is barely visible. But there seems to be a brilliant, curiously symmetrical spot on one face, and this may be connected with TMA-1. I sometimes think that Japetus has been flashing at us like a cosmic heliograph for three hundred years, and we've been too stupid to understand its message.
   "So now you know your real objective, and can appreciate the vital importance of this mission. We are all praying that you can still provide us with some facts for a preliminary announcement; the secret cannot be kept indefinitely.
   "At the moment, we do not know whether to hope or fear. We do not know if, out on the moons of Saturn, you will meet with good or with evil – or only with ruins a thousand times older than Troy."

V – THE MOONS OF SATURN

31 – Survival

   Work is the best remedy for any shock, and Bowman now had work enough for all his lost crewmates. As swiftly as possible, starting with the vital systems without which he and the ship would die, he had to get Discovery fully operational again.
   Life support was the first priority. Much oxygen had been lost, but the reserves were still ample to sustain a single man. The pressure and temperature regulation was largely automatic, and there had seldom been need for Hal to interfere with it. The monitors on Earth could now carry out many of the higher duties of the slain computer, despite the long time lag before they could react to changing situations. Any trouble in the life-support system – short of a serious puncture in the hull – would take hours to make itself apparent; there would be plenty of warning.
   The ship's power, navigation, and propulsion systems were unaffected – but the last two, in any event, Bowman would not need for months, until it was time to rendezvous with Saturn. Even at long range, without the help of an onboard computer, Earth could still supervise this operation. The final orbit adjustments would be somewhat tedious, because of the constant need for checking, but this was no serious problem.
   By far the worst job had been emptying the spinning coffins in the centrifuge. It was well, Bowman thought thankfully, that the members of the survey team had been colleagues, but not intimate friends. They had trained together for only a few weeks; looking back on it, he now realized that even this had been largely a compatibility test.
   When he had finally sealed the empty hibernacula, he felt rather like an Egyptian tomb robber. Now Kaminski, Whitehead, and Hunter would all reach Saturn before him – but not before Frank Poole. Somehow, he derived a strange, wry satisfaction from this thought.
   He did not attempt to find if the rest of the hibernation system was still in working order. Though his life might ultimately depend upon it, this was a problem that could wait until the ship had entered its final orbit. Many things might happen before then.
   It was even possible – though he had not yet looked into the supply position carefully – that by rigorous rationing he might remain alive, without resort to hibernation, until rescue came. But whether he could survive psychologically as well as physically was quite another matter.
   He tried to avoid thinking about such long-range problems, and to concentrate on immediate essentials. Slowly, he cleaned up the ship, checked that its systems were still running smoothly, discussed technical difficulties with Earth, and operated on the minimum of sleep. Only at intervals, during the first weeks, was he able to give much thought to the great mystery toward which he was now inexorably racing – though it was never very far from his mind.
   At last, as the ship slowly settled down once more into an automatic routine – though one that still demanded his constant supervision – Bowman had time to study the reports and briefings sent to him from Earth. Again and again he played back the recording made when TMA-1 greeted the dawn for the first time in three million years. He watched the spacesuited figures moving around it, and almost smiled at their ludicrous panic when it blasted its signal at the stars, paralyzing their radios with the sheer power of its electronic voice.
   Since that moment, the black slab had done nothing. It had been covered up, then cautiously exposed to the Sun again – without any reaction. No attempt had been made to cut into it, partly through scientific caution, but equally through fear of the possible consequences.
   The magnetic field that led to its discovery had vanished at the moment of that radio shriek. Perhaps, some experts theorized, it had been generated by a tremendous circulating current, flowing in a superconductor and thus carrying energy down the ages until it was needed. That the monolith had some internal source of power seemed certain; the solar energy it had absorbed during its brief exposure could not account for the strength of its signal.
   One curious, and perhaps quite unimportant, feature of the block had led to endless argument The monolith was 11 feet high, and 11/4 by 5 feet in cross-section. When its dimensions were checked with great care, they were found to be in the exact ratio 1 to 4 to 9 – the squares of the first three integers. No one could suggest any plausible explanation for this, but it could hardly be a coincidence, for the proportions held to the limits of measurable accuracy. It was a chastening thought that the entire technology of Earth could not shape even an inert block, of any material, with such a fantastic degree of precision. In its way, this passive yet almost arrogant display of geometrical perfection was as impressive as any of TMA-l's other attributes.
   Bowman also listened, with a curiously detached interest, to Mission Control's belated apologia for its programming. The voices from Earth seemed to have a defensive note; be could imagine the recriminations that must now be in progress among those who had planned the expedition.
   They had some good arguments, of course – including the results of a secret Department of Defense study, Project BARSOOM, which had been carried out by Harvard's School of Psychology in 1989. In this experiment in controlled sociology, various sample populations had been assured that the human race had made contact with extraterrestrials. Many of the subjects tested were – with the help of drugs, hypnosis, and visual effects – under the impression that they had actually met creatures from other planets, so their reactions were regarded as authentic.
   Some of these reactions had been quite violent; there was, it seemed, a deep vein of xenophobia in many otherwise normal human beings. In view of mankind's record of lynchings, pogroms, and similar pleasantries, this should have surprised no one; nevertheless, the organizers of the study had been deeply disturbed, and the results had never been released. The five separate panics caused in the twentieth century by radio broadcasts of H.G. Wells's War of the Worlds also reinforced the study's conclusions.
   Despite these arguments, Bowman sometimes wondered if the cultural shock danger was the only explanation for the mission's extreme secrecy. Some hints that had been dropped during his briefings suggested that the U.S.-U.S.S.R. bloc hoped to derive advantage by being the first to contact intelligent extraterrestrials.
   From his present viewpoint, looking back on Earth as a dim star almost lost in the Sun, such considerations now seemed ludicrously parochial.
   He was rather more interested – even though this was now very much water under the bridge – in the theory put forward to account for Hal's behavior. No one would ever be sure of the truth, but the fact that one of the Mission Control 9000s had been driven into an identical psychosis, and was now under deep therapy, suggested that the explanation was the correct one. The same mistake would not be made again; and the fact that Hal's builders had failed fully to understand the psychology of their own creation showed how difficult it might be to establish communication with truly alien beings.
   Bowman could easily believe Dr. Simonson's theory that unconscious feelings of guilt, caused by his program conflicts, had made Hal attempt to break the circuit with Earth. And he liked to think – though this again was something that could never be proved – that Hal had no intention of killing Poole. He had merely tried to destroy the evidence; for once the AE-35 unit reported as burned out was proved to be operational, his lie would be revealed. After that, like any clumsy criminal caught in a thickening web of deception, he had panicked.
   And panic was something that Bowman understood better than he had any wish to, for he had known it twice during his life. The first time was as a boy, when he bad been caught in a line of surf and nearly drowned; the second was as a spaceman under training, when a faulty gauge had convinced him that his oxygen would be exhausted before he could reach safety.
   On both occasions, he had almost lost control of all his higher logical processes; he had been within seconds of becoming a frenzied bundle of random impulses. Both times he had won through, but he knew well enough that any man, in the right circumstances, could be dehumanized by panic.
   If it could happen to a man, then it could happen to Hal; and with that knowledge the bitterness and the sense of betrayal he felt toward the computer began to fade. Now, in any event, it belonged to a past that was wholly overshadowed by the threat, and the promise, of the unknown future.

32 – Concerning E.T.'s

   Apart from hasty meals back in the carrousel – luckily the main food dispensers had not been damaged – Bowman practically lived on the control deck. He catnapped in his seat, and so could spot any trouble as soon as the first signs of it appeared on the display. Under instructions from Mission Control, he had jury-rigged several emergency systems, which were working tolerably well. It even seemed possible that he would survive until the Discovery reached Saturn – which, of course, she would do whether he was alive or not.
   Though he had little enough time for sightseeing, and the sky of space was no novelty to him, the knowledge of what now lay out there beyond the observation ports sometimes made it difficult for him to concentrate even on the problem of survival. Dead ahead, as the ship was now oriented, sprawled the Milky Way, with its clouds of stars so tightly packed that they numbed the mind. There were the fiery mists of Sagittarius, those seething swarms of suns that forever hid the heart of the galaxy from human vision. There was the ominous black shadow of the Coal Sack, that hole in space where no stars shone. And there was Alpha Centauri, nearest of all alien suns – the first stop beyond the Solar System.
   Although outshone by Sirius and Canopus, it was Alpha Centauri that drew Bowman's eyes and mind whenever he looked out into space. For that unwavering point of brightness, whose rays had taken four years to reach him, had come to symbolize the secret debates that now raged on Earth, and whose echoes came to him from time to time.
   No one doubted that there must be some connection between TMA-1 and the Saturnian system, but hardly any scientists would admit that the creatures who had erected the monolith could possibly have originated there. As an abode of life, Saturn was even more hostile than Jupiter, and its many moons were frozen in an eternal winter three hundred degrees below zero. Only one of them – Titan – possessed an atmosphere; and that was a thin envelope of poisonous methane.
   So perhaps the creatures who had visited Earth's Moon so long ago were not merely extraterrestrial, but extrasolar – visitors from the stars, who had established their bases wherever it suited them. And this at once raised another problem: could any technology, no matter how advanced, bridge the awful gulf that lay between the Solar System and the nearest alien sun?
   Many scientists flatly denied the possibility. They pointed out that Discovery, the fastest ship ever designed, would take twenty thousand years to reach Alpha Centauri – and millions of years to travel any appreciable distance across the galaxy. Even if, during the centuries to come, propulsion systems improved out of all recognition, in the end they would meet the impassable barrier of the speed of light, which no material object could exceed. Therefore, the builders of TMA-1 must have shared the same sun as man; and since they had made no appearance in historic times, they were probably extinct.
   A vocal minority refused to agree. Even if it took centuries to travel from star to star, they contended, this might be no obstacle to sufficiently determined explorers. The technique of hibernation, used on Discovery herself, was one possible answer. Another was the self-contained artificial world, embarking on voyages that might last for many generations.
   In any event, why should one assume that all intelligent species were as short-lived as Man? There might be creatures in the universe to whom a thousand-year voyage would present nothing worse than slight boredom...
   These arguments, theoretical though they were, concerned a matter of the utmost practical importance; they involved the concept of "reaction time." If TMA-1 had indeed sent a signal to the stars – perhaps with the help of some further device near Saturn – then it would not reach its destination for years. Even if the response was immediate, therefore, humanity would have a breathing space which could certainly be measured in decades – more probably in centuries. To many people, this was a reassuring thought.
   But not to all. A few scientists – most of them beachcombers on the wilder shores of theoretical physics – asked the disturbing question: "Are we certain that the speed of light is an unbreakable barrier?" It was true that the Special Theory of Relativity had proved to be remarkably durable, and would soon be approaching its first centenary; but it had begun to show a few cracks. And even if Einstein could not be defied, he might be evaded.
   Those who sponsored this view talked hopefully about shortcuts through higher dimensions, lines that were straighter than straight, and hyperspacial connectivity. They were fond of using an expressive phrase coined by a Princeton mathematician of the last century: "Wormholes in space." Critics who suggested that these ideas were too fantastic to be taken seriously were reminded of Niels Bohr's "Your theory is crazy – but not crazy enough to be true."
   If there was disputation among the physicists, it was nothing compared with that among the biologists, when they discussed the hoary old problem: "What would intelligent extraterrestrials look like?" They divided themselves into two opposing camps – one arguing that such creatures must be humanoid, the other equally convinced that "they" would look nothing like men.
   Settling for the first answer were those who believed that the design of two legs, two arms, and main sense organs at the highest point, was so basic and so sensible that it was hard to think of a better one. Of course, there would be minor differences like six fingers instead of five, oddly colored skin or hair, and peculiar facial arrangements; but most intelligent extraterrestrials – usually abbreviated to E.T.'s – would be so similar to Man that they might not be glanced at twice in poor lighting, or from a distance.
   This anthropomorphic thinking was ridiculed by another group of biologists, true products of the Space Age who felt themselves free from the prejudices of the past. They pointed out that the human body was the result of millions of evolutionary choices, made by chance over eons of time. At any one of these countless moments of decision, the genetic dice might have fallen differently, perhaps with better results. For the human body was a bizarre piece of improvisation, full of organs that had been diverted from one function to another, not always very successfully – and even containing discarded items, like the appendix, that were now worse than useless.
   There were other thinkers, Bowman also found, who held even more exotic views. They did not believe that really advanced beings would possess organic bodies at all. Sooner or later, as their scientific knowledge progressed, they would get rid of the fragile, disease-and-accident-prone homes that Nature had given them, and which doomed them to inevitable death. They would replace their natural bodies as they wore out – or perhaps even before that – by constructions of metal and plastic, and would thus achieve immortality. The brain might linger for a little while as the last remnant of the organic body, directing its mechanical limbs and observing the universe through its electronic senses – senses far finer and subtler than those that blind evolution could ever develop.
   Even on Earth, the first steps in this direction had been taken. There were millions of men, doomed in earlier ages, who now lived active and happy lives thanks to artificial limbs, kidneys, lungs, and hearts. To this process there could be only one conclusion – however far off it might be.
   And eventually even the brain might go. As the seat of consciousness, It was not essential; the development of electronic intelligence had proved that. The conflict between mind and machine might be resolved at last in the eternal truce of complete symbiosis.
   But was even this the end? A few mystically inclined biologists went still further. They speculated, taking their cues from the beliefs of many religions, that mind would eventually free itself from matter. The robot body, like the flesh-and-blood one, would be no more than a stepping-stone to something which, long ago, men bad called "spirit."
   And if there was anything beyond that, its name could only be God.

33 – Ambassador

   During the last three months, David Bowman had adapted himself so completely to his solitary way of life that he found it hard to remember any other existence. He had passed beyond despair and beyond hope, and had settled down to a largely automatic routine, punctuated by occasional crises as one or other of Discovery's systems showed signs of malfunctioning.
   But he had not passed beyond curiosity, and sometimes the thought of the goal toward which he was driving filled him with a sense of exaltation – and a feeling of power. Not only was he the representative of the entire human race, but his actions during the next few weeks might determine its very future. In the whole of history, there had never been a situation quite like this. He was an Ambassador Extraordinary – Plenipotentiary – for all mankind.
   That knowledge helped him in many subtle ways. He kept himself neat and tidy; no matter how tired he became, he never skipped a shave. Mission Control, he knew, was watching him closely for the first signs of any abnormal behavior; he was determined that it should watch in vain – at least, for any serious symptoms.
   Bowman was aware of some changes in his behavior patterns; it would have been absurd to expect anything else in the circumstances. He could no longer tolerate silence; except when he was sleeping, or talking over the circuit to Earth, he kept the ship's sound system running at almost painful loudness.
   At first, needing the companionship of the human voice, he had listened to classical plays – especially the works of Shaw, Ibsen, and Shakespeare – or poetry readings from Discovery's enormous library of recorded sounds. The problems they dealt with, however, seemed so remote, or so easily resolved with a little common sense, that after a while he lost patience with them.
   So he switched to opera – usually in Italian or German, so that he was not distracted even by the minimal intellectual content that most operas contained. This phase lasted for two weeks before he realized that the sound of all these superbly trained voices was only exacerbating his loneliness. But what finally ended this cycle was Verdi's Requiem Mass, which he had never heard performed on Earth. The "Dies Irae," roaring with ominous appropriateness through the empty ship, left him completely shattered; and when the trumpets of Doomsday echoed from the heavens, he could endure no more.
   Thereafter, he played only instrumental music. He started with the romantic composers, but shed them one by one as their emotional outpourings became too oppressive. Sibelius, Tchaikovsky, Berlioz, lasted a few weeks, Beethoven rather longer. He finally found peace, as so many others had done, in the abstract architecture of Bach, occasionally ornamented with Mozart.
   And so Discovery drove on toward Saturn, as often as not pulsating with the cool music of the harpsichord, the frozen thoughts of a brain that had been dust for twice a hundred years.

   Even from its present ten million miles, Saturn already appeared larger than the Moon as seen from Earth. To the naked eye it was a glorious spectacle; through the telescope, it was unbelievable.
   The body of the planet might have been mistaken for Jupiter in one of his quieter moods. There were the same bands of cloud – though paler and less distinct than on that slightly larger world – and the same continent-sized disturbances moving slowly across the atmosphere. However, there was one striking difference between the two planets; even at a glance, it was obvious that Saturn was not spherical. It was so flattened at the poles that it sometimes gave the impression of slight deformity.
   But the glory of the rings continually drew Bowman's eye away from the planet; in their complexity of detail, and delicacy of shading, they were a universe in themselves. In addition to the great main gap between the inner and outer rings, there were at least fifty other subdivisions or boundaries, where there were distinct changes in the brightness of the planet's gigantic halo. It was as if Saturn was surrounded by scores of concentric hoops, all touching each other, all so flat that they might have been cut from the thinnest possible paper. The system of the rings looked like some delicate work of art, or a fragile toy to be admired but never touched. By no effort of the will could Bowman really appreciate its true scale, and convince himself that the whole planet Earth, if set down here, would look like a ball bearing rolling round the rim of a dinner plate.
   Sometimes a star would drift behind the rings, losing only a little of its brilliancy as it did so. It would continue to shine through their translucent material – though often it would twinkle slightly as some larger fragment of orbiting debris eclipsed it.
   For the rings, as had been known since the nineteenth century, were not solid: that was a mechanical impossibility. They consisted of countless myriads of fragments – perhaps the remains of a moon that had come too close and had been torn to pieces by the great planet's tidal pull. Whatever their origin, the human race was fortunate to have seen such a wonder; it could exist for only a brief moment of time in the history of the Solar System.
   As long ago as 1945, a British astronomer had pointed out that the rings were ephemeral; gravitational forces were at work which would soon destroy them. Taking this argument backward in time, it therefore followed that they had been created only recently – a mere two or three million years ago.
   But no one had ever given the slightest thought to the curious coincidence that the rings of Saturn had been born at the same time as the human race.

34 – The Orbiting Ice

   Discovery was now deep into the wide-ranging system of moons, and the great planet itself was less than a day ahead. The ship had long since passed the boundary set by outermost Phoebe, moving backward in a wildly eccentric orbit eight million miles from its primary. Ahead of it now lay Japetus, Hyperion, Titan, Rhea, Dione, Tethys, Enceladus, Mimas, Janus – and the rings themselves. All the satellites showed a maze of surface detail in the telescope, and Bowman had relayed back to Earth as many photographs as he could take. Titan alone – three thousand miles in diameter, and as large as the planet Mercury – would occupy a survey team for months; he could give it, and all its cold companions, only the briefest of glances. There was no need for more; already he was quite certain that Japetus was indeed his goal.
   All the other satellites were pitted by occasional meteor craters – though these were much fewer than on Mars – and showed apparently random patterns of light and shade, with here and there a few bright spots that were probably patches of frozen gas. Japetus alone possessed a distinctive geography, and a very strange one indeed.
   One hemisphere of the satellite, which, like its companions, turned the same face always toward Saturn, was extremely dark, and showed very little surface detail. In complete contrast, the other was dominated by a brilliant white oval, about four hundred miles long and two hundred wide. At the moment, only part of this striking formation was in daylight, but the reason for Japetus's extraordinary variations in brilliance was now quite obvious. On the western side of the moon's orbit, the bright ellipse was presented toward the Sun – and the Earth. On the eastern phase, the patch was turned away, and only the poorly reflecting hemisphere could be observed.
   The great ellipse was perfectly symmetrical, straddling the equator of Japetus with its major axis pointing toward the poles; and it was so sharp-edged that it almost looked as if someone had carefully painted a huge white oval on the face of the little moon. It was completely flat, and Bowman wondered if it could be a lake of frozen liquid – though that would hardly account for its startlingly artificial appearance.
   But he had little time to study Japetus on his way into the heart of the Saturnian system, for the climax of the voyage – Discovery's last perturbation maneuver – was rapidly approaching. In the Jupiter fly-by, the ship had used the gravitational field of the planet to increase her velocity. Now she must do the reverse; she had to lose as much speed as possible, lest she escape from the Solar System and fly on to the stars. Her present course was one designed to trap her, so that she would become another moon of Saturn, shuttling back and forth along a narrow, two-million-mile-long ellipse. At its near point it would almost graze the planet; at its far one, it would touch the orbit of Japetus.
   The computers back on Earth, though their information was always three hours late, had assured Bowman that everything was in order. Velocity and altitude were correct; there was nothing more to be done, until the moment of closest approach.
   The immense system of rings now spanned the sky, and already the ship was passing over its outermost edge. As he looked down upon them from a height of some ten thousand miles, Bowman could see through the telescope that the rings were made largely of ice, glittering and scintillating in the light of the Sun. He might have been flying over a snowstorm that occasionally cleared to reveal, where the ground should have been, baffling glimpses of night and stars.
   As Discovery curved still closer toward Saturn, the Sun slowly descended toward the multiple arches of the rings. Now they had become a slim, silver bridge spanning the entire sky; though they were too tenuous to do more than dim the sunlight, their myriads of crystals refracted and scattered it in dazzling pyrotechnics. And as the Sun moved behind the thousand-mile-wide drifts of orbiting ice, pale ghosts of itself marched and merged across the sky, and the heavens were filled with shifting flares and flashes. Then the Sun sank below the rings, so that they framed it with their arches, and the celestial fireworks ceased.
   A little later, the ship curved into the shadow of Saturn, as it made its closest approach over the night side of the planet. Above shone the stars and the rings; below lay a dimly visible sea of clouds. There were none of the mysterious patterns of luminosity that had glowed in the Jovian night; perhaps Saturn was too cold for such displays. The mottled cloudscape was revealed only by the ghostly radiance reflected back from the circling icebergs, still illuminated by the hidden Sun.
   But in the center of the arch there was a wide, dark gap, like the missing span of an uncompleted bridge, where the shadow of the planet lay across its rings.
   Radio contact with Earth had been broken, and could not be resumed until the ship emerged from the eclipsing bulk of Saturn. It was perhaps as well that Bowman was too busy now to think of his suddenly enhanced loneliness; for the next few hours, every second would be occupied as he checked the braking maneuvers, already programmed by the computers on Earth.
   After their months of idleness, the main thrusters began to blast out their miles-long cataracts of glowing plasma. Gravity returned, though briefly, to the weightless world of the control deck. And hundreds of miles below, the clouds of methane and frozen ammonia blazed with a light that they had never known before, as Discovery swept, a fierce and tiny sun, through the Saturnian night.
   At last, the pale dawn lay ahead; the ship, moving more and more slowly now, was emerging into day. It could no longer escape from the Sun, or even from Saturn – but it was still moving swiftly enough to rise away from the planet until it grazed the orbit of Japetus, two million miles out.
   It would take Discovery fourteen days to make that climb, as she coasted once more, though in reverse order, across the paths of all the inner moons. One by one she would cut through the orbits of Janus, Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion – worlds bearing the names of gods and goddesses who had vanished only yesterday, as time was counted here.
   Then she would meet Japetus, and must make her rendezvous. If she failed, she would fall back toward Saturn and repeat her twenty-eight-day ellipse indefinitely.
   There would be no chance for a second rendezvous if Discovery missed on this attempt. The next time around, Japetus would be far away, almost on the other side of Saturn.
   It was true that they would meet again, when the orbits of ship and satellite meshed for a second time. But that appointment was so many years ahead that, whatever happened, Bowman knew he would not witness it.