The Sentinel

  The cloud of electrified gas would probably miss the Earth completely. But if it did not, it would arrive in just over a day. Spaceships could protect themselves, with their shielding and their powerful magnetic screens; but the lightly built solar yachts, with their paper-thin walls, were defenseless against such a menace. The crews would have to be taken off, and the race abandoned.

  John Merton knew nothing of this as he brought Diana around the Earth for the second time. If all went well, this would be the last circuit, both for him and for the Russians. They had spiraled upward by thousands of miles, gaining energy from the Sun’s rays. On this lap, they should escape from Earth completely, and head outward on the long run to the Moon. It was a straight race now; Sunbeam’s crew had finally withdrawn exhausted, after battling valiantly with their spinning sail for more than a hundred thousand miles.

  Merton did not feel tired; he had eaten and slept well, and Diana was behaving herself admirably. The autopilot, tensioning the rigging like a busy little spider, kept the great sail trimmed to the Sun more accurately than any human skipper could have. Though by this time the two square miles of plastic sheet must have been riddled by hundreds of micrometeorites, the pinhead-sized punctures had produced no falling off of thrust.

  He had only two worries. The first was shroud line number eight, which could no longer be adjusted properly. Without any warning, the reel had jammed; even after all these years of astronautical engineering, bearings sometimes seized up in vacuum. He could neither lengthen nor shorten the line, and would have to navigate as best he could with the others. Luckily, the most difficult maneuvers were over; from now on, Diana would have the Sun behind her as she sailed straight down the solar wind. And as the old-time sailors had often said, it was easy to handle a boat when the wind was blowing over your shoulder.

  His other worry was Lebedev, still dogging his heels three hundred miles astern. The Russian yacht had shown remarkable maneuverability, thanks to the four great panels that could be tilted around the central sail. Her flipovers as she rounded the Earth had been carried out with superb precision. But to gain maneuverability she must have sacrificed speed. You could not have it both ways; in the long, straight haul ahead, Merton should be able to hold his own. Yet he could not be certain of victory until, three or four days from now, Diana went flashing past the far side of the Moon.

  And then, in the fiftieth hour of the race, just after the end of the second orbit around Earth, Markoff sprang his little surprise.

  “Hello, John,” he said casually over the ship-to-ship circuit. “I’d like you to watch this. It should be interesting.”

  Merton drew himself across to the periscope and turned up the magnification to the limit. There in the field of view, a most improbable sight against the background of the stars, was the glittering Maltese cross of Lebedev, very small but very clear. As he watched, the four arms of the cross slowly detached themselves from the central square, and went drifting away, with all their spars and rigging, into space.

  Markoff had jettisoned all unnecessary mass, now that he was coming up to escape velocity and need no longer plod patiently around the Earth, gaining momentum on each circuit. From now on, Lebedev would be almost unsteerable—but that did not matter; all the tricky navigation lay behind her. It was as if an old-time yachtsman had deliberately thrown away his rudder and heavy keel, knowing that the rest of the race would be straight downwind over a calm sea.

  “Congratulations, Dimitri,” Merton radioed. “It’s a neat trick. But it’s not good enough. You can’t catch up with me now.”

  “I’ve not finished yet,” the Russian answered. “There’s an old winter’s tale in my country about a sleigh being chased by wolves. To save himself, the driver has to throw off the passengers one by one. Do you see the analogy?”

  Merton did, all too well. On this final straight lap, Dimitri no longer needed his copilot. Lebedev could really be stripped down for action.

  “Alexis won’t be very happy about this,” Merton replied. “Besides, it’s against the rules.”

  “Alexis isn’t happy, but I’m the captain. He’ll just have to wait around for ten minutes until the Commodore picks him up. And the regulations say nothing about the size of the crew—you should know that.”

  Merton did not answer; he was too busy doing some hurried calculations, based on what he knew of Lebedev’s design. By the time he had finished, he knew that the race was still in doubt. Lebedev would be catching up with him at just about the time he hoped to pass the Moon.

  But the outcome of the race was already being decided, ninety-two million miles away.

  On Solar Observatory Three, far inside the orbit of Mercury, the automatic instruments recorded the whole history of the flare. A hundred million square miles of the Sun’s surface exploded in such blue-white fury that, by comparison, the rest of the disc paled to a dull glow. Out of that seething inferno, twisting and turning like a living creature in the magnetic fields of its own creation, soared the electrified plasma of the great flare. Ahead of it, moving at the speed of light, went the warning flash of ultraviolet and X rays. That would reach Earth in eight minutes, and was relatively harmless. Not so the charged atoms that were following behind at their leisurely four million miles an hour—and which, in just over a day, would engulf Diana, Lebedev, and their accompanying little fleet in a cloud of lethal radiation.

  The Commodore left his decision to the last possible minute. Even when the jet of plasma had been tracked past the orbit of Venus, there was a chance that it might miss the Earth. But when it was less than four hours away, and had already been picked up by the Moon-based radar network, he knew that there was no hope. All solar sailing was over, for the next five or six years—until the Sun was quiet again.

  A great sigh of disappointment swept across the solar system. Diana and Lebedev were halfway between Earth and Moon, running neck and neck—and now no one would ever know which was the better boat. The enthusiasts would argue the result for years; history would merely record: “Race canceled owing to solar storm.”

  When John Merton received the order, he felt a bitterness he had not known since childhood. Across the years, sharp and clear, came the memory of his tenth birthday. He had been promised an exact scale model of the famous spaceship Morning Star, and for weeks had been planning how he would assemble it, where he would hang it in his bedroom. And then, at the last moment, his father had broken the news. “I’m sorry, John—it cost too much money. Maybe next year . . . ”

  Half a century and a successful lifetime later, he was a heartbroken boy again.

  For a moment, he thought of disobeying the Commodore. Suppose he sailed on, ignoring the warning? Even if the race was abandoned, he could make a crossing to the Moon that would stand in the record books for generations.

  But that would be worse than stupidity; it would be suicide—and a very unpleasant form of suicide. He had seen men die of radiation poisoning, when the magnetic shielding of their ships had failed in deep space. No—nothing was worth that . . .

  He felt as sorry for Dimitri Markoff as for himself. They had both deserved to win, and now victory would go to neither. No man could argue with the Sun in one of its rages, even though he might ride upon its beams to the edge of space.

  Only fifty miles astern now, the Commodore’s launch was drawing alongside Lebedev, preparing to take off her skipper. There went the silver sail, as Dimitri—with feelings that he would share—cut the rigging. The tiny capsule would be taken back to Earth, perhaps to be used again; but a sail was spread for one voyage only.

  He could press the jettison button now, and save his rescuers a few minutes of time. But he could not do it; he wanted to stay aboard to the very end, on the little boat that had been for so long a part of his dreams and his life. The great sail was spread now at right angles to the Sun, exerting its utmost thrust. Long ago, it had torn him clear of Earth, and Diana was still gaining speed.

  Then, out of nowhere, beyo
nd all doubt or hesitation, he knew what must be done. For the last time, he sat down before the computer that had navigated him halfway to the Moon.

  When he had finished, he packed the log and his few personal belongings. Clumsily, for he was out of practice, and it was not an easy job to do by oneself, he climbed into the emergency survival suit. He was just sealing the helmet when the Commodore’s voice called over the radio.

  “We’ll be alongside in five minutes, Captain. Please cut your sail, so we won’t foul it.”

  John Merton, first and last skipper of the sun yacht Diana, hesitated a moment. He looked for the last time around the tiny cabin, with its shining instruments and its neatly arranged controls, now all locked in their final positions. Then he said into the microphone: “I’m abandoning ship. Take your time to pick me up. Diana can look after herself.”

  There was no reply from the Commodore, and for that he was grateful. Professor van Stratten would have guessed what was happening—and would know that, in these final moments, he wished to be left alone.

  He did not bother to exhaust the air lock, and the rush of escaping gas blew him gently out into space. The thrust he gave her then was his last gift to Diana. She dwindled away from him, sail glittering splendidly in the sunlight that would be hers for centuries to come. Two days from now she would flash past the Moon; but the Moon, like the Earth, could never catch her. Without his mass to slow her down, she would gain two thousand miles an hour in every day of sailing. In a month, she would be traveling faster than any ship that man had ever built.

  As the Sun’s rays weakened with distance, so her acceleration would fall. But even at the orbit of Mars, she would be gaining a thousand miles an hour in every day. Long before then, she would be moving too swiftly for the Sun itself to hold her. Faster than a comet had ever streaked in from the stars, she would be heading out into the abyss.

  The glare of rockets, only a few miles away, caught Merton’s eye. The launch was approaching to pick him up—at thousands of times the acceleration that Diana could ever attain. But its engines could burn for a few minutes only, before they exhausted their fuel—while Diana would still be gaining speed, driven outward by the Sun’s eternal fires, for ages yet to come.

  “Goodbye, little ship,” said John Merton. “I wonder what eyes will see you next, how many thousand years from now?”

  At last he felt at peace, as the blunt torpedo of the launch nosed up beside him. He would never win the race to the Moon; but his would be the first of all man’s ships to set sail on the long journey to the stars.

  A MEETING

  WITH MEDUSA

  “A Meeting with Medusa” was written in January 1971 for one specific purpose. Over the previous decade I had accumulated some 50,000 words of short stories, and needed another 15,000 to make up a complete volume. So I sat down at the typewriter (I still have one gathering dust somewhere, but if this word processor breaks down I’m going back to pen and paper . . . ) and “Medusa” was the result. It was as simple as that.

  Well, not really. I had been thinking about Jupiter for a long time; witness the final sequence in the movie 2001: A Space Odyssey. And in some ways the sequel 2010: Odyssey Two is also a sequel to this story; I had room there to develop in more detail some of the concepts I had first worked out in “Medusa.”

  And by then, of course, our knowledge of Jupiter had been enormously increased, thanks to the marvelous Pioneer and Voyager missions. None of this new information, I am happy to say, has invalidated any of these earlier ideas. On the contrary: there are some very suspicious, sharp-edged blobs floating around in the Jovian atmosphere . . .

  “A Meeting with Medusa” was the last story I ever wrote, before concentrating entirely on novels. It won a Playboy editorial award and the Science Fiction Writers of America’s annual Nebula, so I am proud to have made it my swan song . . . for the present, at any rate.

  And here’s a very strange coincidence. Until I started to write this note, I’d completely forgotten that I used the name “Kon-Tiki” for the exploring vehicle. And so I was able to autograph a copy of “Medusa” for Thor Heyerdahl—when I met him this morning, right here in Colombo . . .

  1. A Day to remember

  THE Queen Elizabeth was over three miles above the Grand Canyon, dawdling along at a comfortable hundred and eighty, when Howard Falcon spotted the camera platform closing in from the right. He had been expecting it—nothing else was cleared to fly at this altitude—but he was not too happy to have company. Although he welcomed any signs of public interest, he also wanted as much empty sky as he could get. After all, he was the first man in history to navigate a ship three-tenths of a mile long . . .

  So far, this first test flight had gone perfectly; ironically enough, the only problem had been the century-old aircraft carrier Chairman Mao, borrowed from the San Diego Naval Museum for support operations. Only one of Mao’s four nuclear reactors was still operating, and the old battle-wagon’s top speed was barely thirty knots. Luckily, wind speed at sea level had been less than half this, so it had not been too difficult to maintain still air on the flight deck. Though there had been a few anxious moments during gusts, when the mooring lines had been dropped, the great dirigible had risen smoothly, straight up into the sky, as if on an invisible elevator. If all went well, Queen Elizabeth IV would not meet Chairman Mao again for another week.

  Everything was under control; all test instruments gave normal readings. Commander Falcon decided to go upstairs and watch the rendezvous. He handed over to his second officer, and walked out into the transparent tubeway that led through the heart of the ship. There, as always, he was overwhelmed by the spectacle of the largest single space ever enclosed by man.

  The ten spherical gas cells, each more than a hundred feet across, were ranged one behind the other like a line of gigantic soap bubbles. The tough plastic was so clear that he could see through the whole length of the array, and make out details of the elevator mechanism, more than a third of a mile from his vantage point. All around him, like a three-dimensional maze, was the structural framework of the ship—the great longitudinal girders running from nose to tail, the fifteen hoops that were the circular ribs of this sky-borne colossus, and whose varying sizes defined its graceful, streamlined profile.

  At this low speed, there was little sound—merely the soft rush of wind over the envelope and an occasional creak of metal as the pattern of stresses changed. The shadowless light from the rows of lamps far overhead gave the whole scene a curiously submarine quality, and to Falcon this was enhanced by the spectacle of the translucent gasbags. He had once encountered a squadron of large but harmless jellyfish, pulsing their mindless way above a shallow tropical reef, and the plastic bubbles that gave Queen Elizabeth her lift often reminded him of these—especially when changing pressures made them crinkle and scatter new patterns of reflected light.

  He walked down the axis of the ship until he came to the forward elevator, between gas cells one and two. Riding up to the Observation Deck, he noticed that it was uncomfortably hot, and dictated a brief memo to himself on his pocket recorder. The Queen obtained almost a quarter of her buoyancy from the unlimited amounts of waste heat produced by her fusion power plant. On this lightly loaded flight, indeed, only six of the ten gas cells contained helium; the remaining four were full of air. Yet she still carried two hundred tons of water as ballast. However, running the cells at high temperatures did produce problems in refrigerating the access ways; it was obvious that a little more work would have to be done there.

  A refreshing blast of cooler air hit him in the face when he stepped out onto the Observation Deck and into the dazzling sunlight streaming through the plexiglass roof. Half a dozen workmen, with an equal number of superchimp assistants, were busily laying the partly completed dance floor, while others were installing electric wiring and fixing furniture. It was a scene of controlled chaos, and Falcon found it hard to believe that everything would be ready for the maiden voyage, onl
y four weeks ahead. Well, that was not his problem, thank goodness. He was merely the Captain, not the Cruise Director.

  The human workers waved to him, and the “simps” flashed toothy smiles, as he walked through the confusion, into the already completed Skylounge. This was his favorite place in the whole ship, and he knew that once she was operating he would never again have it all to himself. He would allow himself just five minutes of private enjoyment.

  He called the bridge, checked that everything was still in order, and relaxed into one of the comfortable swivel chairs. Below, in a curve that delighted the eye, was the unbroken silver sweep of the ship’s envelope. He was perched at the highest point, surveying the whole immensity of the largest vehicle ever built. And when he had tired of that—all the way out to the horizon was the fantastic wilderness carved by the Colorado River in half a billion years of time.

  Apart from the camera platform (it had now fallen back and was filming from amidships) he had the sky to himself. It was blue and empty, clear down to the horizon. In his grandfather’s day, Falcon knew, it would have been streaked with vapor trails and stained with smoke. Both had gone: the aerial garbage had vanished with the primitive technologies that spawned it, and the long-distance transportation of this age arced too far beyond the stratosphere for any sight or sound of it to reach Earth. Once again, the lower atmosphere belonged to the birds and the clouds—and now to Queen Elizabeth IV.

  It was true, as the old pioneers had said at the beginning of the twentieth century: this was the only way to travel—in silence and luxury, breathing the air around you and not cut off from it, near enough to the surface to watch the everchanging beauty of land and sea. The subsonic jets of the 1980s, packed with hundreds of passengers seated ten abreast, could not even begin to match such comfort and spaciousness.

  Of course, the Queen would never be an economic proposition, and even if her projected sister ships were built, only a few of the world’s quarter of a billion inhabitants would ever enjoy this silent gliding through the sky. But a secure and prosperous global society could afford such follies and indeed needed them for their novelty and entertainment. There were at least a million men on Earth whose discretionary income exceeded a thousand new dollars a year, so the Queen would not lack for passengers.