The cause of break-off was usually sensory deprivation; robbed of the normal flow of messages from all its inputs the ever-active brain started to build its own world, which seldom coincided with reality. The cure was simple; if a man was kept busy on assigned tasks, and was in continual communication with his colleagues, he was in little danger.

  So Bowman had to have a deputy, and the obvious choice was Peter.

  Whitehead sometimes called himself "Engineer in charge of everything else." Another of Whitehead's favorite sayings was that every problem had a technical solution-it was just a matter of choosing the best. His genius for trouble-shooting was probably another aspect of his highpowered imagination, for he seemed able to identify himself with recalcitrant machinery. There were some who claimed that he had paranormal powers, for whereas most engineers had to kick their black boxes when they misbehaved, Whitehead merely had to glare at them.

  On the tenth day, at last satisfied that the ship was running flawlessly, Bowman called a final crew conference. Anyone looking at the six men gathered on the control deck could have divided them at once into two categories. Bowman and Whitehead were in good physical shape, whereas the other four were sleek and plump. There had been many jokes about condemned men eating hearty breakfasts, and cattle being fattened for the slaughter. But the low-residue, high-calorie diet was an essential preparation for the long sleep; some fuel was necessary, even at the low metabolic level of hibernation. When they awoke in little over half a year, most of this fat would be gone.

  And so would Earth, that brilliant star now dominating the sky. The next time the four sleepers opened their eyes, their home planet would be lost against the glare of the Sun; and Jupiter would be lord of the heavens.

  It was a solemn moment, this parting of the ways; no one felt like making any of the usual wisecracks, for all knew that they might not meet again. And the men who were about to hibernate, though they had been through this before, and thoroughly understood its necessity, were reluctant to go. Any one of them would have changed places with Bowman or Whitehead.

  "This is for the record," said Bowman, a little self-consciously, glancing out of the corner of his eye at the TV camera which surveyed the Control Center, and which continually reported the situation to Earth. At this close range it was still operating in real time; out at Jupiter, it would be sending only one frame a second-but that was quite adequate for monitoring purposes.

  "All the scheduled checkouts have been completed; there have been no unexpected problems. We are now at Day 10, which is the time planned for hibernation to commence. It is my opinion that we should continue according to program. If any of you disagree, please say so now."

  There was a rather restless silence. Everyone seemed waiting for someone else to speak, but no one did. And no one knew that Dr. Poole, who had secret orders of his own, was carefully watching both Bowman and Whitehead for any signs of disturbance. He was satisfied by what he saw.

  "Very well," continued Bowman. "You all know what to do. As soon as you're ready, please call Doc."

  It was all very crisp and impersonal and businesslike, but the individual good-byes would not take place under the gaze of the TV camera. One by one, Kimball and Hunter and Kaminski and Poole drifted back to their cabins in the carousel, and put their few belongings in order. And presently each one spoke privately over a radio circuit to Earth, and for the only time on the voyage the ship's recorders were shut off, while verbal farewells were transmitted. To most of them this was an ordeal they would have preferred to avoid, and they were secretly glad that there could be no direct reply. By this time, the round-trip radio delay was over two minutes, and a conversation with Earth was impossible.

  At the last moment, Poole made the final tests of the men he would soon be following into sleep. To each, Bowman delivered appropriate versions of the same rather forced jest: "You lucky bastard! Pete and I will be working like dogs for seven months, while you take it easy." Then the electronarcosis currents started to pulse, and Discovery's operational crew diminished to five, to four, to three....

  "That's it," said Dr. Poole. "All sleeping like babies." He looked at Bowman with a serious, thoughtful expression; they were alone together, while Whitehead stood watch on the control deck. "How do you feel?" he asked.

  "A little tired, but very glad it's gone so smoothly. Don't worry about us, Kel. The first time we cut our fingers, or feel colds coming on, we'll wake you up."

  Poole chuckled. "You make me feel like an old-time country doctor, wondering whether the telephone will let him have an undisturbed night. O.K.-do your stuff."

  Bowman adjusted the biosensor straps around Poole's chest and right arm, checked the head bands carefully, and triggered the high-pressure hypodermic. There was a brief hiss as the drugs were forced into Poole's bloodstream.

  "Happy dreams, Doc," said Bowman.

  "Be seeing you," answered Poole. He started counting: "One ... Two ... Three...." but got no further.

  For a moment, Bowman stood looking at his sleeping friend, half envious of his freedom from responsibility. Then, with quite unnecessary quietness, he tiptoed away and went to join Whitehead at Control.

  He found his shipmate staring, with undisguised fascination, at the four little panels on the situation display board marked KAMINSKI, KIMBALL, POOLE, HUNTER. Each showed a small constellation of green lights, indicating that all was well.

  And on each was a tiny screen, across which three sets of lines traced leisurely rhythms, so hypnotic that Bowman also found it hard to tear away his eyes. One line showed respiration, another pulse, another EEG.

  But the panels marked BOWMAN and WHITEHEAD were blank and lifeless. Their time would come a year from now, out at the orbit of Jupiter.

  RUNAWAY

  To Bowman, the first intimation of trouble was a quiet voice saying over the open radio circuit. "Dave-I'm having control problems." Whitehead sounded slightly annoyed, but not in the least alarmed.

  Before Bowman could answer, he saw the pod emerge from the shadow of the ship, only twenty feet beneath the main observation window. It was under full power, heading roughly along the line of Discovery's orbit.

  "What's the trouble?" he called. For a few seconds there was no answer, and the pod was already a hundred feet away before Whitehead replied.

  "Throttle jammed at full thrust," he said, quite calmly "I'm building up a little distance before I try anything."

  That made sense, a runaway pod needed plenty of space to maneuver. And there was still no cause for real worry; Bowman was quite sure that Whitehead would soon fix the trouble, as he had always done in the past.

  The seconds ticked slowly by; the pod was still gaining speed-and now it was so far away that it was barely recognizable. Though Whitehead would have no difficulty in homing on the ship from a distance of many miles, he had better not leave matters until too late for his main drive would empty the propellant tanks in a very few minutes.

  The pod was now a tiny spot, its distance impossible to judge by the eye. Bowman locked the navigation radar on it, and was surprised to find that it was still only two miles away. But, far more serious, it was already traveling at a hundred and ninety miles an hour.

  "Peter!" cried Bowman. "What the hell's happening? Can't you fix it?"

  For the first time, there was a note of alarm in Whitehead's voice.

  "Controls won't respond," he said. "I'm pulling the main fuse to cut off power. Call you back."

  A second later, his radio went dead. While waiting, Bowman searched for the pod with a telescope, and found it quickly enough. With a sinking heart, he saw the little cloud of mist flaring from the rocket nozzle, and knew that the capsule was still accelerating.

  Whitehead was back on the air almost at once.

  "No use," he said abruptly. "Trying to turn with auxiliaries."

  It was a tricky maneuver, but the obvious next step. Even if he could not turn off the main drive, he should be able to spin the pod around so
that he reversed the direction in which it was building up its uncontrollable velocity. Then the runaway would eventually be brought to rest, and presently it would start coming back again.

  Tense and pale, with a dreadful feeling of helplessness, Bowman stared through the telescope. In its field of view, the pod seemed only a few feet away, and he could see every detail of its construction. Then, to his enormous relief, little spurts appeared from the attitude-control nozzles, and the capsule began to turn slowly on its axis.

  The treacherous main drive swung out of sight, still firing, next he had a broadside view-then he was looking straight into the bay window at the seated figure of his friend. He could have seen Whitehead's expression, if it had not been for the glare of reflected sunlight on the transparent panels.

  "You've done it!" he cried. "Thank God!"

  The capsule was still racing away at over two hundred miles an hour-but at least it was now losing speed, no longer gaining it, as its jet acted as a brake.

  "Looks like it," said Whitehead, his voice showing his immense relief. "I knew Betty wouldn't let me down, if I treated her properly."

  Though it seemed ages, it was less than a minute before Bowman could tell, even without the aid of radar, that Whitehead was on the way back. Presently the capsule began to grow in the field of the telescope-slowly at first-then rapidly-then too rapidly.

  "Still can't cut the damn thing," said Whitehead. "Hate to waste all this fuel, but I'll just have to swing to and fro until I run out of gas."

  It seemed to Bowman that the capsule was now heading straight toward the ship; they were out of the frying pan and into the fire. The risk of losing Whitehead had now been replaced by an even more serious danger.

  "Watch your track," he called anxiously. "I think you're on a collision course."

  "I know," said Whitehead breathlessly. "Trying to flip her around again."

  He was too late. For one hideous moment, the capsule seemed to be heading straight for the observation windows of the Control Deck. Then, barely in time, the steering jets opened up, and the runaway vehicle skimmed above the curving hull of the ship and behind Bowman's field of view.

  "Sorry about that," said Whitehead. "Give you a wider berth next-"

  The sound of the crash came simultaneously over the radio and through the fabric of the ship. Bowman half rose from his seat, waiting for the alarms to go and for the damage signals to start flashing. But nothing happened; it must have been a glancing impact-no real harm done. To Discovery, at least; but what about the capsule?

  "Peter!" he called. "Are you all right? Do you read me?"

  There was no reply. Bowman turned the gain of the radio full up, and listened intently. The carrier wave was still coming in, but that proved very little. He had hoped to hear the sound of Whitehead's breathing, even if he had been knocked unconscious. If the capsule had been cracked, of course, there would be no breathing-and no sound, except for the muffled roar of the jet drive, as loud as ever through the metal framework of the runaway.

  That roar was still audible over the radio, but there was nothing else. Bowman called again, and again, Whitehead did not reply. At the same time, he swiftly ran through the pictures on the rear- view monitors, and after a quick search located the capsule a few hundred yards away.

  To his great relief, it appeared intact-but it was still under power. Whether he was dead or alive, it was carrying Whitehead inexorably away from the ship; and there was nothing whatsoever he could do about it.

  "Peter!" he called. "Peter! Can you hear me?"

  Still no answer-only that maddening jet roar. It seemed to last forever; and then, suddenly, it stopped. The capsule had at last used up its fuel.

  Once more, Bowman strained to detect the sound of breathing over the hiss of the carrier wave. The microphone was only a few inches from Whitehead's mouth; if the space pod still contained air, he should hear something....

  He did, and with a sigh of relief he resumed his own breathing. First there were some soft bangings, then a mumbled exclamation like a drunken man talking in his sleep. That was followed by a short blast of well-organized profanity; Whitehead was wholly conscious again.

  "Hello, Dave," he said, even before Bowman could call him. "I'm O.K. now-just a bruise on my forehead-no other damage. Will you get a fix?"

  A quick glance at the radar showed Bowman that the capsule was still less than five miles away. That was a perfectly trivial distance-but it was increasing rapidly. For despite its periods of braking, the pod was now racing away from Discovery at three hundred and sixty miles an hour.

  Every minute it would increase its distance by six miles- and so on, hour after hour, day after day. But before long, of course, this would be of no practical interest to Peter Whitehead.

  Bowman reported the facts; then he asked quickly: "What's your oxygen reserve, Pete?"

  "About . . . five hours."

  "Only five?"

  "Yes. It was a single-tank job-so I thought."

  Bowman did not say what had flashed through his mind, but he was sure that it had already occurred to Whitehead. No matter how much oxygen the pod carried, it might make no difference now.

  For several seconds there was no sound over the radio circuit; then Whitehead said, with a kind of resigned sadness: "Well, I guess that's it, Dave."

  "I'm damned if it is. I'm coming out to catch you. Hold on."

  There was another pause, before Whitehead replied: "You can't do that-not enough safety time, anyhow. You know you can't leave the ship."

  "I bloody well can; Athena can handle things. I'm coming."

  "Let's not fool ourselves. What was that velocity vector?"

  "Five hundred thirty feet a second."

  "Give that sum to Athena, if you like. I know the answer already." So, in his heart, did Bowman. If he risked abandoning the ship and his four sleeping companions, he could eventually catch up with Whitehead. But then they would both be several hundred miles from Discovery-and still moving away from her at that deadly five hundred thirty feet a second. The rescue pod would first have to cancel that speed, and not until then could it start on the return journey. With that extra payload, it could never make it home.

  Nevertheless, Bowman fed the figures to Athena. The answer came back instantly: IMPOSSIBLE.

  Just for a moment, before his years of training asserted themselves, he was overcome by a sense of blind rage, and wanted to hammer his fists against the cold display panels of the computer. But that would be no help to Whitehead or to himself. It was impossible to argue with the laws of mathematics, and stupid to feel anger at them. If one chose to live by the implacable equations of the Universe, then when the time came one must also die by them.

  But he refused to admit defeat; men did not give up as easily as this. He remembered Whitehead's own favorite saying: "Every problem has a technical solution." There must be a solution for this problem, if only he could think of it.

  The situation was so absurd, so utterly ironic. Here he was in a ship that could cross half a billion miles of space and travel at thousands of miles an hour-and he could not save a friend drifting slowly to his death a mere ten miles away. If he returned to Earth, who would ever understand his terrible dilemma? Always there would be the unspoken question: "But surely you could have done something?''

  But this was no TV space opera, where the hero conjured some brilliant answer out of his hat. This was a problem for which there was no solution.

  "Dave," said the loudspeaker suddenly. "Can the ship do anything?"

  Though Whitehead was not a propulsion expert, he certainly knew better than this. The very fact that he had asked such a question indicated some loss of self-control, but Bowman could hardly blame him. A desperate man would clutch at any straw.

  "I'm sorry, Peter," he answered gently and patiently. "You know the main reactor has been shut down and the thrusters have all been mothballed. It takes over a day to test them and run them up."

  And even then,
he might have added, it would not have helped. The ship's acceleration was so low that it could never overtake the pod before the five hours were up.

  That was going to be the longest five hours in Bowman's life.

  FIRST MAN TO JUPITER

  And then while Bowman was still considering his next move, Whitehead asked an extraordinary question.