The Space Trilogy

by Arthur C. Clarke

  “Thank you very much. I remember all about it now. And the missile?”

  Hilton slid smoothly into the conversation.

  “That’s simply a little automatic rocket with radio control and a very high terminal speed. It’s used to carry cargoes between the space-stations, or to chase after spaceships when they’ve left anything behind. When it gets into radio range it will pick up our transmitter and home on to us. Hey, Bob,” he said suddenly, turning to Scott, “why haven’t they sent it direct to Mars? It could get there long before we do.”

  “Because its little passengers wouldn’t like it. I’ll have to fix up some cultures for them to live in, and look after them like a nursemaid. Not my usual line of business, but I think I can remember some of the stuff I did at St. Thomas’s.”

  “Wouldn’t it be appropriate,” said Mackay with one of his rare attempts at humour, “if someone went and painted the Red Cross outside?”

  Gibson was thinking deeply.

  “I was under the impression,” he said after a pause, “that life on Mars was very healthy, both physically and psychologically.”

  “You mustn’t believe all you read in books,” drawled Bradley. “Why anyone should ever want to go to Mars I can’t imagine. It’s flat, it’s cold, and it’s full of miserable half-starved plants looking like something out of Edgar Allan Poe. We’ve sunk millions into the place and haven’t got a penny back. Anyone who goes there of his own free will should have his head examined. Meaning no offense, of course.”

  Gibson only smiled amicably. He had learned to discount Bradley’s cynicism by about ninety per cent; but he was never quite sure how far the other was only pretending to be insulting. For once, however, Captain Norden asserted his authority; not merely to stop Bradley from getting away with it, but to prevent such alarm and despondency from spreading into print. He gave his electronics officer an angry glare.

  “I ought to tell you, Martin,” he said, “that although Mr. Bradley doesn’t like Mars, he takes an equally poor view of Earth and Venus. So don’t let his opinions depress you.”

  “I won’t,” laughed Gibson. “But there’s one thing I’d like to ask.”

  “What’s that?” said Norden anxiously.

  “Does Mr. Bradley take as ‘poor a view,’ as you put it, of Mr. Bradley as he does of everything else?”

  “Oddly enough, he does,” admitted Norden. “That shows that one at least of his judgments is accurate.”

  “Touché,” murmured Bradley, for once at a loss. “I will retire in high dudgeon and compose a suitable reply. Meanwhile, Mac, will you get the missile’s co-ordinates and let me know when it should come into range?”

  “All right,” said Mackay absently. He was deep in Chaucer again.

  Four

  During the next few days Gibson was too busy with his own affairs to take much part in the somewhat limited social life of the Ares. His conscience had smitten him, as it always did when he rested for more than a week, and he was hard at work again.

  His crew-mates (for Gibson no longer regarded himself as a privileged passenger) respected his solitude. At first they had wandered into his room whenever they were passing, to talk about nothing in particular or to exchange solemn complaints about the weather. This had been veru pleasant, but Gibson had been forced to stop it with a 'DANGER—MAN AT WORK' notice pinned on his door. Needless to say this had rapidly become adorned with ribald comments in various hands, but it had served its purpose.

  The typewriter had been disentangled from his belongings and now occupied the place of honour in the little cabin. Sheets of manuscript lay everywhere—Gibson was an untidy worker—and had to be prevented from escaping by elastic bands. There had been a lot of trouble with the flimsy carbon paper, which had a habit of getting into the airflow and gluing itself against the ventilator, but Gibson had now mastered the minor techniques of life under zero gravity. It was amazing how quickly one learned them, and how soon they became a part of everyday life.

  Gibson had found it very hard to get his impressions of space down on paper; one could not very well say “space is awfully big” and leave it at that. The take-off from Earth had taxed his skill to the utmost. He had not actually lied, but anyone who read his dramatic description of the Earth falling away beneath the blast of the rocket would certainly never get the impression that the writer had then been in a state of blissful unconsciousness, swiftly followed by a state of far from blissful consciousness.

  As soon as he had produced a couple of articles which would keep Ruth happy for a while (she had meanwhile sent three further radiograms of increasing asperity) he went Northwards to the Signals Office. Bradley received the sheets of MSS. with marked lack of enthusiasm.

  “I suppose this is going to happen every day from now on,” he said glumly.

  “I hope so—but I’m afraid not. It depends on my inspiration.”

  “There’s a split infinitive right here on the top of page 2.”

  “Excellent; nothing like ‘em.”

  “You’ve put ‘centrifugal’ on page 3 where you mean ‘centripetal.’”

  “Since I get paid by the word, don’t you think it’s generous of me to use such long ones?”

  “There are two successive sentences on page 4 beginning with ‘And.’”

  “Look here, are you going to send the damned stuff, or do I have to do it myself?”

  Bradley grinned.

  “I’d like to see you try. Seriously, though, I should have warned you to use a black ribbon. Contrast isn’t so good with blue, and though the facsimile sender will be able to handle it all right at this range, when we get farther away from Earth it’s important to have a nice, clean signal.”

  As he spoke, Bradley was slipping the quarto sheets into the tray of the automatic transmitter. Gibson watched, fascinated, as they disappeared one by one into the maw of the machine and emerged five seconds later into the wire collecting-basket. It was strange to think that his words were now racing out through space in a continuous stream, getting a million kilometres farther away every three seconds. He was a little surprised, however, that it took so long to transmit a single sheet: on Earth, he knew, there were machines that could send hundreds of pages of print a minute.

  "That's a complicated story," explained Bradley when he put the question to him. "We can't use high-speed facsimile over hundred-million-kilomtre ranges with the low power we've got. The higher the speed, the bigger the band-width of the system, and so the more noise it picks up to swamp the signal. That's why telephony isn't practical on the very long distance circuits."

  "I think I get the idea," said Gibson. "But how is it that there's no trouble arranging radio broadcasts from Mars or Venus, even when they're half-way round the Sun?"

  "Because on the planets the communication companies can focus their beams with lenses a hundred metres across, and can put a score of megawatts into them. Our little aerial system is just five mtres in diameter, and we can't manage more than a few hundred kilowatts before blowing our output stages sky-high."

  "Oh," said Gibson thoughtfully, and he left it at that. He was just collecting his MSS. sheets again when a buzzer sounded somewhere in the jungle of dials, switches, and meter panels that covered practically the entire wall of the little office. Bradley shot across to one of his receivers and proceeded to do incomprehensible things with great rapidity. A piercing whistle started to come from a loudspeaker.

  “The carrier’s in range at last,” said Bradley, “but it’s a long way off—at a guess I’d say it will miss us by a hundred thousand kilometres.”

  “What can we do about that?”

  “Very little. I’ve got our own beacon switched on, and if it picks up our signals it will home on to us automatically and navigate itself to within a few kilometres of us.”

  “And if it doesn’t pick us up?”

  “Then it will just go shooting on out of the Solar System. It’s travelling fast enough to escape from the Sun; so are we, fo
r that matter.”

  “That’s a cheerful thought. How long would it take us?”

  “To do what?”

  “To leave the system.”

  “A couple of years, perhaps. Better ask Mackay. I don’t know all the answers—I’m not like one of the characters in your books!”

  “You may be one yet,” said Gibson darkly, and withdrew.

  The approach of the missile had added an unexpected—and welcome—element of excitement to life aboard the Ares. Once the first fine careless rapture had worn off, space-travel could become exceedingly monotonous. It would be different in future days, when the liner was crowded with life, but there were times when her present loneliness could be very depressing.

  The missile sweepstake had been organized by Dr. Scott, but the prizes were held firmly by Captain Norden. Some calculations of Mackay’s indicated that the projectile would miss the Ares by a hundred and twenty-five thousand kilometres, with an uncertainty of plus or minus thirty thousand. Most of the bets had been placed near the most probable value, but some pessimists, mistrusting Mackay completely, had gone out to a quarter of a million kilometres. The bets weren’t in cash, but in far more useful commodities such as cigarettes, candies, and other luxuries. Since the crew’s personal weight allowance was strictly limited, these were far more valuable than pieces of paper with marks on them. Mackay had even thrown a half-bottle of whiskey into the pool, and had thereby staked a claim to a volume of space about twenty thousand kilometres across. He never drank the stuff himself, he explained, but was taking some to a compatriot on Mars, who couldn’t get the genuine article and was unable to afford the passage back to Scotland. No one believed him, which, as the story was more or less true, was a little unfair.

  “Jimmy!”

  “Yes, Captain Norden.”

  “Have you finished checking the oxygen gauges?”

  “Yes, sir. All OK.”

  “What about that automatic recording gear those physicists have put in the hold? Does it look as if it’s still working?”

  “Well, it’s making the same sort of noises as it did when we started.”

  “Good. You’ve cleaned up that mess in the kitchen where Mr. Hilton let the milk boil over?”

  “Yes, Captain.”

  “Then you’ve really finished everything?”

  “I suppose so, but I was hoping—”

  “That’s fine. I’ve got a rather interesting job for you—something quite out of the usual run of things. Mr. Gibson wants to start polishing up his astronautics. Of course, any of us could tell him all he wants to know, but—er—you’re the last one to come from college and maybe you could put things across better. You’ve not forgotten the beginner’s difficulties—we’d tend to take too much for granted. It won’t take much of your time—just go along when he asks and deal with his questions. I’m sure you can manage.”

  Exit Jimmy, glumly.

  “Come in,” said Gibson, without bothering to look up from his typewriter. The door opened behind him and Jimmy Spencer came floating into the room.

  “Here’s the book, Mr. Gibson. I think it will give you everything you want. It’s Richardson’s Elements of Astronautics, special lightweight edition.”

  He laid the volume in front of Gibson, who turned over the thin sheets with an interest that rapidly evaporated as he saw how quickly the proportion of words per page diminished. He finally gave up halfway through the book after coming across a page where the only sentence was “Substituting for the value of perihelion distance from Equation 15.3, we obtain…” All else was mathematics.

  “Are you quite sure this is the most elementary book in the ship?” he asked doubtfully, not wishing to disappoint Jimmy. He had been a little surprised when Spencer had been appointed as his unofficial tutor, but had been shrewd enough to guess the reason. Whenever there was a job that no one else wanted to do, it had a curious tendency to devolve upon Jimmy.

  “Oh yes, it really is elementary. It manages without vector notation and doesn’t touch perturbation theory. You should see some of the books Mackay has in his room. Each equation takes a couple of pages of print.”

  “Well, thanks anyway. I’ll give you a shout when I get stuck. It’s about twenty years since I did any maths, though I used to be quite hot at it once. Let me know when you want the book back.”

  “There’s no hurry, Mr. Gibson. I don’t very often use it now I’ve got on to the advanced stuff.”

  “Oh, before you go, maybe you can answer a point that’s just cropped up. A lot of people are still worried about meteors, it seems, and I’ve been asked to give the latest information on the subject. Just how dangerous are they?”

  Jimmy pondered for a moment.

  “I could tell you, roughly,” he said, “but if I were you I’d see Mr. Mackay. He’s got tables giving the exact figures.”

  “Right, I’ll do that.”

  Gibson could quite easily have rung Mackay but any excuse to leave his work was too good to be missed. He found the little astrogator playing tunes on the big electronic calculating machine.

  “Meteors?” said Mackay. “Ah, yes, a very interesting subject. I’m afraid, though, that a great deal of highly misleading information has been published about them. It wasn’t so long ago that people believed a spaceship would be riddled as soon as it left atmosphere.”

  “Some of them still do,” replied Gibson. “At least, they think that large-scale passenger travel won’t be safe.”

  Mackay gave a snort of disgust.

  “Meteors are considerably less dangerous than lightning and the biggest normal one is a lot smaller than a pea.”

  “But, after all, one ship has been damaged by them!”

  “You mean the Star Queen ? One serious accident in the last five years is quite a satisfactory record. No ship has ever actually been lost through meteors.”

  “What about the Pallas ?”

  “No one knows what happened to her. That’s only the popular theory. It’s not at all popular among the experts.”

  “So I can tell the public to forget all about the matter?”

  “Yes. Of course, there is the question of dust—”

  “Dust?”

  “Well, if by meteors you mean fairly large particles, from a couple of millimetres upwards, you needn’t worry. But dust is a nuisance, particularly on space-stations. Every few years someone has to go over the skin to locate the punctures. They’re usually far too small to be visible to the eye, but a bit of dust moving at fifty kilometres a second can get through a surprising thickness of metal.”

  This sounded faintly alarming to Gibson, and Mackay hastened to reassure him.

  “There really isn’t the slightest need to worry,” he repeated. “There’s always a certain hull leakage taking place: the air supply simply takes it in its stride.”

  However busy Gibson might be, or pretend to be, he always found time to wander restlessly around the echoing labyrinths of the ship, or to sit looking at the stars from the equatorial observation galley. He had formed a habit of going there during the daily concert. At 15.00 hours precisely the ship’s public address system would burst into life and for an hour the music of Earth would whisper or roar through the empty passageways of the Ares. Every day a different person would choose the programs, so one never knew what was coming—though after a while it was easy to guess the identity of the arranger. Norden played light classics and opera; Hilton practically nothing but Beethoven and Tchaikovsky. They were regarded as hopeless lowbrows by Mackay and Bradley, who indulged in astringent chamber music and atonal cacophonies of which no one else could make head or tail, or indeed particularly desired to. The ship’s micro-library of books and music was so extensive that it would outlast a lifetime in space. It held, in fact, the equivalent of a quarter of a million books and some thousands of orchestral works, all recorded in electronic patterns, awaiting the orders that would bring them into life.

  Gibson was sitting in the observation gal
lery, trying to see how many of the Pleiades he could resolve with the naked eye, when a small projectile whispered past his ear and attached itself with a “thwack!” to the glass of the port, where it hung vibrating like an arrow. At first sight, indeed, this seemed exactly what it was and for a moment Gibson wondered if the Cherokee were on the warpath again. Then he saw that a large rubber sucker had replaced the head, while from the base, just behind the feathers, a long, thin thread trailed away into the distance. At the end of the thread was Dr. Robert Scott, MD, hauling himself briskly along like an energetic spider.

  Gibson was still composing some suitably pungent remark when, as usual, the doctor got there first.

  “Don’t you think it’s cute?” he said. “It’s got a range of twenty meters—only weighs half a kilo, and I’m going to patent it as soon as I get back to Earth.”

  “Why?” said Gibson, in tones of resignation.

  “Good gracious, can’t you see? Suppose you want to get from one place to another inside a space-station where there’s no rotational gravity. All you’ve got to do is to fire at any flat surface near your destination, and reel in the cord. It gives you a perfect anchor until you release the sucker.”

  “And just what’s wrong with the usual way of getting around?”

  “When you’ve been in space as long as I have,” said Scott smugly, “you’ll know what’s wrong. There are plenty of hand-holds for you to grab in a ship like this. But suppose you want to go over to a blank wall at the other side of a room, and you launch yourself through the air from wherever you’re standing. What happens? Well, you’ve got to break your fall somehow, usually with your hands, unless you can twist round on the way. Incidentally, do you know the commonest complaint a spaceship M.O. has to deal with? It’s sprained wrists, and that’s why. Anyway, even when you get to your target you’ll bounce back unless you can grab hold of something. You might even get stranded in mid-air. I did that once in Space Station Three, in one of the big hangars. The nearest wall was fifteen meters away and I couldn’t reach it.”