"And I suspect," said Kaminski, "that the people who designed our friend here failed to think far enough ahead. What's the purpose of food and oxygen? Why, merely combustion, to produce energy-at a miserable few percent efficiency. This is what our really advanced extraterrestrial will look like. May I?"

  He took the pen and pad from Floyd, and rapidly shaded the egg-shaped body until the air and food intakes were no longer visible. Then, at waist level, he sketched in an electric power point-and ran a long cable to a socket a few feet away.

  There was general laughter, in which Kaminski did not join, though his eyes twinkled.

  "The cyborg-the electromechanical organism. And even he-it is only a stepping stone to the next stage-the purely electronic intelligence, with no flesh and-blood body at all. The robot, if you like-though I prefer to call it the autonomous computer."

  "And what would that look like?" asked the vice-president.

  Before Kaminski could answer, Whitehead annexed his sketchpad and started to draw swiftly.

  "It could look just like one of our present computers," he said. "On the other hand-it could be this."

  He handed the pad to Mr. Kelly. It showed a simple, unadorned tetrahedron.

  "I see-TMA-l itself."

  "Exactly, sir. There may be no pyramid-builders-there may only be pyramids. They may be our super-intelligences."

  "That would be disappointing," said the Vice-President. "I don't know what I expect you to find out on Jupiter, but I hope it's more exciting than that."

  "l don't," interjected Mrs. Kelly. Then she began to laugh.

  After a while she pulled herself together, obviously with an effort.

  "I've just had the most hilarious idea," she said. "Suppose you're right, and they send back an ambassador. Can you imagine that welcoming parade down Fifth Avenue- and the President sharing his Cadillac with a large, black pyramid?"

  The Vice-President began to grin, and very quickly the grin spread right across his face. He made no comment, but everyone remembered the stories of his occasional disagreements with the Chief Executive.

  It was quite obvious that he could imagine that parade; and that, on the whole, he rather liked the idea.

  It was a glorious night; there had been rain earlier in the day, and the freshly washed sky was unusually dark. Bowman had never seen so many stars above Washington; and now, soon after midnight, the brightest of them all was rising in the east.

  "Look, Mr. Vice-President," he said, as they took their final leave. "Our target-eight months from now."

  They all stood in thoughtful silence, wholly forgetting the other guests, not even hearing the soft background of music from the band inside the house. Around them was the sleeping city, dominated by the floodlit bubble of the Capitol dome. And over that ghostly white hemisphere, Jupiter was rising.

  MISS0N TO JUPITER

  Like everything else in 2001, the good ship Discovery passed through many transformations before it reached its final shape. Obviously, it could not be a conventional chemically propelled vehicle, and there was little doubt that it would have to be nuclear-powered for the mission we envisaged. But how should the power be applied? There were several alternatives-electric thrusters using charged particles (the ion drive); jets of extremely hot gas (plasma) controlled by magnetic fields, or streams of hydrogen expanding through nozzles after they had been heated in a nuclear reactor. All these ideas have been tested on the ground, or in actual spaceflight; all are known to work.

  The final decision was made on the basis of aesthetics rather than technology; we wanted Discovery to look strange yet plausible, futuristic but not fantastic. Eventually we settled on the plasma drive, though I must confess that there was a little cheating. Any nuclear-powered vehicle must have large radiating surfaces to get rid of the excess heat generated by the reactors-but this would make Discovery look somewhat odd. Our audiences already had enough to puzzle about; we didn't want them to spend half the picture wondering why spaceships should have wings. So the radiators came off.

  There was also a digression-to the great alarm, as already mentioned, of the Art Department-into a totally different form of propulsion. During the late 1950's, American scientists had been studying an extraordinary concept ("Project Orion") which was theoretically capable of lifting payloads of thousands of tons directly into space at high efficiency. It is still the only known method of doing this, but for rather obvious reasons it has not made much progress.

  Project Orion is a nuclear-pulse system-a kind of atomic analog of the wartime V-2 or buzz- bomb. Small (kiloton) fission bombs would be exploded, at the rate of one every few seconds, fairly close to a massive pusherplate which would absorb the impulse from the explosion; even in the vacuum of space, the debris from such a mini-bomb can produce quite a kick.

  The plate would be attached to the spacecraft by a shock-absorbing system that would smooth out the pulses, so that the intrepid passengers would have a steady, one gravity ride-unless the engine started to knock.

  Although Project Orion sounds slightly unbelievable, extensive theoretical studies, and some tests using conventional explosives, showed that it would certainly work- and it would be many times cheaper than any other method of space propulsion. It might even be cheaper, per passenger seat, than conventional air transport-if one was thinking in terms of million-ton vehicles. But the whole project was grounded by the Nuclear Test Ban Treaty, and in any case it will be quite a long time before NASA, or anybody else, is thinking on such a grandiose scale. Still, it is nice to know that the possibility exists, in case the need ever arises for a lunar equivalent of the Berlin Airlift....

  When we started work on 2001, some of the Orion documents had just been declassified, and were passed on to us by scientists indignant about the demise of the project. It seemed an exciting idea to show a nuclear-pulse system in action, and a number of design studies were made of it; but after a week or so Stanley decided that putt-putting away from Earth at the rate of twenty atom bombs per minute was just a little too comic. Moreover- recalling the finale of Dr. Strangelove-it might seem to a good many people that he had started to live up to his own title and had really learned to Love the Bomb. So he dropped Orion, and the only trace of it that survives in both movie and novel is the name.

  As has already been indicated by the frantic entries in my log, the story line took a couple of years of hard labor to pin down. We had the beginning and (approximately) the end; it was the center portion which refused to stay in one place. I sometimes felt that we were wrestling with a powerful and uncooperative snake, anchored at both ends.

  FLIGHT PAY

  The six members of the crew made their departures from Earth as quietly as possible, on separate and unannounced flights-some from the Kennedy Spaceport, some from the Baikonur Cosmodrome. They had all said goodbye to their families and friends, and had given countless interviews. They wanted no publicity during their last moments on Earth, and most of them managed to avoid it.

  The actual launch date was still a week ahead. They would need all that amount of time to become accustomed to working and living as a team aboard Discovery under actual flight conditions-conditions which could never be completely simulated on Earth. The "Orbital Shakedown" could be carried out safely yet realistically with Space Station One hovering only a few miles away ready to provide immediate help in case of emergency

  That preflight week was also essential for medical reasons. As Dr. Poole expressed it, with concise accuracy, "It gives us a chance to share our germs." The ship would be rigorously quarantined; its inhabitants would catch no diseases from outside, and if they developed any allergies to each other, something could still be done about it.

  There were countless little problems, but no major ones-at least, of a technical nature. However, Bowman was distracted from more important matters by one annoying piece of bureaucratic ineptitude

  From the earliest days, the financial rewards of astronauts had always been the subject of
controversy. Everyone agreed that they should be paid well-but how well?

  After a long series of policy changes in which both the Space Agency and the individual astronauts had come in for much criticism, general rules had been worked out to everyone's satisfaction. On this mission, where every man except Dr. Poole was an Astronaut, First Class, all crew members would receive the standard basic pay for that grade, which worked out at $34,945 per annum. By special arrangement with the Federal Health Insurance Agency which had somehow got into the act, Dr. Poole's salary was supposed to be made up to that of his colleagues. For reasons that no one even attempted to understand, he actually received $35,105.

  However-and this was where the trouble started-that was only the basic pay. On this mission there would be a flight bonus of $25,000 a year, as well as a substantial lump sum on return and provision for dependents in case of death or disablement. Bowman was just okaying the final payroll statements in the Administration Office of Space Station One when he noticed, quite by chance, that the flight bonus would not commence until the moment of injection into the transfer orbit to Jupiter.

  The amount involved was only about $500 a man, but Bowman was quite sure that on earlier missions the full bonus had been paid from the beginning of the final checkout period in Earth orbit, when the full crew was assembled under captain's orders and the ship was in all respects operational - even though the flight had not actually begun. So he sent back a memorandum to Accounts, quoting precedents.

  There is a type of civil servant (fortunately not as common as the critics sometimes maintain) who refuses to admit a mistake. Such a one appeared to be at the other end of the line. He refused to budge, and so did Bowman. So while the captain of the multi-billion-dollar Discovery was taking over command of his ship, he was conducting an increasingly astringent debate with an anonymous Washington bureaucrat for a $500 bonus. They were still shooting radio memos at each other when the voyage began.

  DISCOVERY

  To the sightseers, cameramen, and commentators aboard Space Station One, it was hard to tell that the ship was actually moving. There was, of course, none of the thunder and fury of a takeoff from earth as Discovery pulled out of her parking orbit; the only sign of acceleration was the unbearable, blue-white radiance of the plasma jets blasting out their streams of ionized gas at hundreds of miles a second.

  Even aboard the ship, the only sound produced by the drive units was a faint, far-off hissing, and their thrust was so low that weight was almost negligible. But they could maintain that thrust for hour after hour, as they spewed out their jets of star-stuff, hotter than the face of the sun. When they finally closed down, Discovery would be hurtling starward at almost thirty miles a second.

  There was little for Bowman and Kaminski-acting as co-pilot-to do except to monitor all systems, and to be prepared to make decisions if a situation arose outside the computer's experience or programming. But Athena was working perfectly, measuring the ship's mounting speed and checking it second by second with the radars back on earth. From time to time she made minute corrections utterly imperceptible to the men aboard, to bring Discovery back onto the precomputed path.

  Less than an hour after departure, she announced the uneventful passing of the voyage's first milestone. The announcement was for the benefit of the waiting earth, for the crew knew it already from their instruments, nevertheless, that cool, soprano voice filled them with many conflicting emotions:

  "We have now attained escape velocity. I repeat: We have now attained escape velocity."

  Here, already receding behind them, was what had once seemed the ultimate goal of rocket engineering. Whatever happened now, Earth could never call them back. Though power might fail in the next second, theirs would still be the freedom of space, to circle the sun forever on an independent planetary orbit.

  There were still hours of acceleration ahead, but this was the psychological break-off point. Even though the cloud-girdled globe of Earth still filled the sky, she had lost them. Her backward- tugging gravity could now merely reduce their speed; it was no longer able to cancel and reverse it.

  No man, however many times he went into space, could fail to react to this moment. His feelings depended on what he had left behind; for most, it was an instant of ineffable sadness, like the last sight of home to a seafarer who knows he will never return. For this was a parting that no men had ever experienced before this generation-a parting from the world more final than any earlier death, for Earth could not even reclaim their bones.

  Soon afterward, the first booster unit was discarded. The acceleration ebbed to zero as the last precious drops of propellant were drained from the tank, and Discovery floated inert against the stars. Then the explosive bolts separated cleanly, and there was a gentle nudge as small solid rockets eased the two stages apart.

  It was strange to see another manmade object hanging there in space, where a moment ago there had been only Earth, Sun, and stars. As the jets began to thrust again, the booster slowly dwindled astern; it seemed to be falling back to earth, but that of course was an illusion. It was now a satellite of the Sun, never to return to the world that had built it.

  Three hours later, for the first time in the history of manned flight, Discovery passed another milestone.

  "We have now attained solar escape," said Athena. "I repeat: we have now attained solar escape velocity."

  At their control panels Bowman and Kaminski looked at each other with a mingling of pride and awe. Now they had not merely escaped from Earth, they had loosened the grip of the Sun itself. Unless they slowed themselves deliberately, they could now go sailing out past all the planets-gradually losing speed, but never falling back into the Solar System. In a few years they would pass the orbit of Pluto and go drifting onward, slowly but inevitably, toward the stars. It might take them a million years to reach the very nearest; but they would get there.

  And still the speed mounted, minute by minute, through eight full hours of gentle acceleration. Earth was now a brilliant, waning crescent three hundred thousand miles sunward; though it was still a mere stone's throw away, astronomically speaking, it already seemed more distant than Jupiter. To Discovery's crew, it lay in their past, and they might never return to it. Jupiter lay in their future- and nothing, except the incredibly rare chance of a direct collision with a large meteorite or an asteroid, could prevent them from reaching it. For the ship was easing itself, with exquisite precision, into the final orbit.

  "One minute from injection," said Athena. "Cutting main drive in ten seconds."

  Par away, the barely audible hissing of the jets died into silence. With their passing went also the last sensation of weight, except for occasional ghostly pats and nudges as the low-powered vernier jets made infinitesimal adjustments to the orbit. Soon even these were finished; and Athena announced: "On course for Jupiter. Estimated transit time two hundred nineteen days five hours."

  THE LONG SLEEP

  Every day the Sun was two million miles farther away, and the Earth was no more than the most brilliant of the stars. Discovery was hurtling effortlessly out into the night, her drive units quiescent, but all her other systems functioning at full efficiency.

  This was the final shakedown period, when the crew would acquire the skills that could never be learned on Earth, or even in free orbit. One by one they crosschecked each other's performances, studied all that was known or suspected about their still-distant goal, and reacted to simulated disasters.

  Of these, the most feared were fire and meteorites. Even more than a ship of the sea, a ship of space is vulnerable to fire. It contains great stores of concentrated energy-chemical, mechanical, electrical, nuclear-any of which may be accidentally unleashed. Every other day, at unexpected times, Bowman would hold a fire-control exercise, and all the heat-sensing alarms were tested with almost fanatical regularity.

  As for meteorites, one could only hope for the best and put one's faith in statistics. Complete safety was impossible; every day,
many thousands of dust particles would bombard the ship, but the vast majority would be so tiny that the mark they made on the outer skin could be seen only through a microscope. The few that did penetrate would be stopped by the inner hull.

  If everything went completely according to plan, there would be no need for even a single member of the crew to stay out of hibernation until Jupiter was reached, Athena could attend to all the running of the ship. On a seven month voyage, however, the unexpected was bound to happen; hence it was wise to have a man available at a moment's notice.

  And any man, no matter how stable and well balanced, needed a back-up at least as badly as did Athena. Otherwise, the sense of isolation might overpower him, and he would move into that realm of inhuman detachment that had in the early days of astronautics, caused so many accidents.

  The psychologists disliked the term "break-off," because it gave the impression of abruptness; but the name had stuck. The first men to fly alone in high-altitude balloons, and the pioneer explorers of the underwater world, had experienced the phenomenon as long ago as the 1950's. It was a sense of remoteness, and of total separation from everyday life, which was not in the least unpleasant. Indeed, it could be positively exhilarating-and that was its greatest danger; for in extreme cases, it could lead to delusions of omnipotence. Divers had been known to swim from deep bases without their breathing gear; astronauts had ignored the plain warnings of their instruments. Some had escaped the consequences of their rashness; many had not.