A Fall of Moondust

by Arthur C. Clarke

  “Harris is a very careful driver,” said the Commissioner. “He’s done this trip scores of times.”

  “Everyone can make mistakes; it’s easy to misjudge your distance when you’re driving by earthlight.”

  Commissioner Davis barely heard him; he was thinking of all the arrangements he might have to make if the worst came to the worst. He’d better start by getting the Legal Branch to check the indemnity forms. If any relatives started suing the Tourist Commission for a few million dollars, that would undo his entire publicity campaign for the next year—even if he won.

  The Ground Traffic officer gave a nervous cough.

  “If I might make a suggestion,” he said to the Chief Engineer. “We could call Lagrange. The astronomers up therr may be able to see something.”

  “At night?” asked Davis skeptically. “From fifty thousand kilometers up?”

  “Easily, if her searchlights are still burning. It’s worth trying.”

  “Excellent idea,” said the Chief Engineer. “Do that right away.”

  He should have thought of that himself, and wondered if there were any other possibilities he had overlooked. This was not the first occasion he had been forced to pit his wits against this strange and beautiful world, so breath-taking in her moments of magic—so deadly in her times of peril. She would never be wholly tamed, as Earth had been, and perhaps that was just as well. For it was the lure of the untouched wilderness and the faint but ever-present hint of danger that now brought the tourists as well as the explorers across the gulfs of space. He would prefer to do without the tourists—but they helped to pay his salary.

  And now he had better start packing. This whole crisis might evaporate, and Selene might turn up again quite unaware of the panic she had caused. But he did not think this would happen, and his fear deepened to certainty as the minutes passed. He would give her another hour; then he would take the suborbital shuttle to Port Roris and to the realm of his waiting enemy, the Sea of Thirst.

  When the PRIORITY RED signal reached Lagrange, Thomas Lawson, Ph.D., was fast asleep. He resented the interruption; though one needed only two hours’ sleep in twenty-four when living under zero gravity, it seemed a little unfair to lose even that. Then he grasped the meaning of the message, and was fully awake. At last it looked as if he would be doing something useful here.

  Tom Lawson had never been very happy about this assignment; he had wanted to do scientific research, and the atmosphere aboard Lagrange II was much too distracting. Balanced here between Earth and Moon, in a cbsmic tightrope act made possible by one of the obscurer consequences of the law of gravitation, the satellite was an astronautical maid-of-all-work. Ships passing in both directions took their fixes from it, and used it as a message center—though there was no truth in the rumor that they stopped to pick up mail. Lagrange was also the relay station for almost all lunar radio traffic, because the whole earthward-facing side of the Moon lay spread beneath it.

  The hundred-centimeter telescope had been designed to look at objects billions of times farther away than the Moon, but it was admirably suited for this job. From so close at hand, even with the low power, the view was superb. Tom seemed to be hanging in space immediately above the Sea of Rains, looking down upon the jagged peaks of the Apennines as they glittered in the morning light. Though he had only a sketchy knowledge of the Moon’s geography, he could recognize at a glance the great craters of Archimedes and Plato, Aristillus and Eudoxus, the dark scar of the Alpine Valley, and the solitary pyramid of Pico, casting its long shadow across the plain.

  But the daylight region did not concern him; what he sought lay in the darkened crescent where the sun had not yet risen. In some ways, that might make his task simpler. A signal lamp—even a hand torch—would be easily visible down there in the night. He checked the map co-ordinates, and punched the control buttons. The burning mountains drifted out of his field of view, and only blackness remained, as he stared into the lunar night that had just swallowed more than twenty men and women.

  At first he could see nothing-certainly no winking signal light, flashing its appeal to the stars. Then, as his eyes grew more sensitive, he could see that this land was not wholly dark. It was glimmering with a ghostly phosphorescence as it lay bathed in the earthlight, and the longer he looked, the more details he could see.

  There were the mountains to the east of Rainbow Bay, waiting for the dawn that would strike them soon. And there—my God, what was that star shining in the darkness? His hopes soared, then swiftly crashed. That was only the lights of Port Roris, where even now men would be waiting anxiously for the results of his survey.

  Within a few minutes, he had convinced himself that a visual search was useless. There was not the slightest chance that he could see an oblect no bigger than a bus, down there in that faintly luminous landscape. In the daytime, it would have been different; he could have spotted Selene at once by the long shadow she cast across the Sea. But the human eye was not sensitive enough to make this search by the light of the waning Earth, from a height of fifty thousand kilometers.

  This did not worry Tom. He had scarcely expected to see anything, on this first visual survey. It was a century and a half since astronomers had had to rely upon their eyesight; today, they had far more delicate weapons—a whole armory of light amplifiers and radiation detectors. One of these, he was certain, would be able to find Selene.

  He would not have been so sure of this had he known that she was no longer upon the surface of the Moon.

  CHAPTER FOUR

  When Selene came to rest, both crew and passengers were still too stricken by astonishment to utter a sound. Captain Harris was the first to recover, perhaps because he was the only one who had any idea of what had happened.

  It was a cave-in, of course; they were not rare, though none had ever been recorded in the Sea of Thirst. Deep down in the Moon, something had given way; possibly the infinitesimal weight of Selene had itself triggered the collapse. As Pat Harris rose shakily to his feet, he wondered what line of talk he had better use to the passengers. He could hardly pretend that everything was under control and that they’d be on their way again in five minutes; on the other hand, panic was liable to set in if he revealed the true seriousness of the situation. Sooner or later he would have to, but until then it was essential to maintain confidence.

  He caught Miss Wilkins’ eye as she stood at the back of the cabin, behind the expectantly waiting passengers. She was very pale, but quite composed; he knew that he could rely on her, and flashed her a reassuring smile.

  “We seem to be in one piece,” he began in an easy, conversational style. “We’ve had a slight accident, as you’ll gather, but things could be worse.” (How? a part of his mind asked him. Well, the hull could have been fractured. . . . So you want to prolong the agony? He shut off the interior monologue by an effort of will.) “We’ve been caught in a landslip-a moonquake, if you like. There’s certainly no need to be alarmed; even if we can’t get out under our own power, Port Roris will soon have someone here. Meanwhile, I know that Miss Wilkins was just going to serve refreshments, so I suggest you all relax while I—ah—do whatever proves necessary.”

  That seemed to have gone over quite well. With a silent sigh of relief, he turned back to the controls. As he did so, he noticed one of the passengers light a cigarette.

  It was an automatic reaction, and one that he felt very much like sharing. He said nothing; that would have destroyed the atmosphere his little speech had created. But he caught the man’s eye just long enough for the message to go home; the cigarette had been stubbed out before he resumed his seat.

  As he switched on the radio, Pat heard the babble of conversation start up behind him. When a group of people were talking together, you could gather their mood even if you could not hear the individual words. He could detect annoyance, excitement, even amusement—but, as yet, very little fear. Probably those who were speaking did not realize the full danger of the situation; the ones
who did were silent.

  And so was the ether. He searched the wave bands from end to end, and found only a faint crackle from the electrified dust that had buried them. It was just as he had expected. This deadly stuff, with its high metallic content, was an almost perfect shield. It would pass neither radio waves nor sound; when he tried to transmit, he would be like a man shouting from the bottom of a well that was packed with feathers.

  He switched the beacon to the high-powered emergency setting, so that it automatically broadcast a distress signal on the MOONCRASH band. If anything got through, this would; there was no point in trying to call Port Roris himself, and his fruitless efforts would merely upset the passengers. He left the receiver operating on Selene’s assigned frequency, in case of any reply, but he knew that it was useless. No one could hear them; no one could speak to them. As far as they were concerned, the rest of the human race might not exist.

  He did not brood over this setback for very long. He had expected it, and there was too much else to do. With the utmost care, he checked all the instruments and gauges. Everything appeared to be perfectly normal, except that the temperature was just a shade high. That also was to be expected, now that the dust blanket was shielding them from the cold of space.

  His greatest worry was the thickness of that blanket, and the pressure it was exerting on the boat. There must be thousands of tons of the stuff above _Selene_--and her hull had been designed to withstand pressure from within, not from without. If she went too deep, she might be cracked like an eggshell.

  How deep the cruiser was, he had no idea. When he had caught his last glimpse of the stars, she was about ten meters below the surface, and she might have been carried down much farther by the suction of the dust. It would be advisable—even though it would increase their oxygen consumption—to put up the internal pressure and thus take some of the strain off the hull.

  Very slowly, so that there would be no telltale popping of ears to alarm anyone, he boosted the cabin pressure by twenty per cent. When he had finished, he felt a little happier. He was not the only one, for as soon as the pressure gauge had stabilized at its new level, a quiet voice said over his shoulder: “I think that was a very good idea.”

  He twisted around to see what busybody was spying on him, but his angry protest died unborn. On his first quick inspection, Pat had recognized none of the passengers; now, however, he could tell that there was something vaguely familiar about the stocky, gray-haired man who had come forward to the driver’s position.

  “I don’t want to intrude, Captain—you’re the skipper here. But I thought I’d better introduce myself in case I can help. I’m Commodore Hansteen.”

  Pat stared, slack-jawed, at the man who had led the first expedition to Pluto, who had probably landed on more virgin planets and moons than any explorer in history. All he could say to express his astonishment was “You weren’t down on the passenger list!”

  The Commodore smiled.

  “My alias is Hanson. Since I retired, I’ve been trying to do a little sight-seeing without quite so much responsibility. And now that I’ve shaved off my beard, no one ever recognizes me.”

  “I’m very glad to have you here,” said Pat, with deep feeling. Already some of the weight seemed to have lifted from his shoulders; the Commodore would be a tower of strength in the difficult hours—or days—that lay ahead.

  “If you don’t mind,” continued Hansteen, with that same careful politeness, “I’d appreciate an evaluation. To put it bluntly, how long can we last?”

  “Oxygen’s the limiting factor, as usual. We’ve enough for about seven days, assuming that no leaks develop. So far. there are no signs of any.”

  “Well, that gives us time to think. What about food and water?”

  “We’ll be hungry, but we won’t starve. There’s an emergency reserve of compressed food, and of course the air purifiers will produce all the water we need. So there’s no problem there.”

  “Power?”

  “Plenty, now that we’re not using our motors.”

  “I notice that you haven’t tried to call Base.”

  “It’s useless; the dust blankets us completely. I’ve put the beacon on emergency—that’s our only hope of getting a signal through, and it’s a slim one.”

  “So they’ll have to find us in some other way. How long do you think it will take them?”

  “That’s extremely difficult to say. The search will begin as soon as our twenty hundred hours transmission is missed, and they’ll know our general area. But we may have gone down without leaving any trace—you’ve seen how this dust obliterates everything. And even when they do find us—“

  “How will they get us out?”

  “Exactly.”

  Skipper of twenty-seat dust-cruiser and Commodore of space stared at each other in silence, as their minds circled the same problem. Then, cutting across the low murmur of conversation, they heard a very English voice call out: “I say, Miss—this is the first decent cup of tea I’ve drunk on the Moon. I thought no one could make it here. My congratulations.”

  The Commodore chuckled quietly.

  “He ought to thank you, not the stewardess,” he said, pointing to the pressure gauge.

  Pat smiled rather wanly in return. That was true enough; now that he had put up the cabin pressure, water must be boiling at nearly its normal, sea-level temperature back on Earth. At last they could have some hot drinks—not the usual tepid ones. But it did seem a somewhat extravagant way to make tea, not unlike the reputed Chinese method of roasting pig by burning down the entire house.

  “Our big problem,” said the Commodore (and Pat did not in the least resent that “our”), “is to maintain morale. I think it’s important, therefore, for you to give a pep talk about the search procedure that must be starting now. But don’t be too optimistic; you mustn’t give the impression that someone will be knocking on the door inside half an hour. That might make it difficult if—well, if we have to wait several days.”

  “It won’t take me long to describe the MOONCRASH organization,” said Pat. “And, frankly, it wasn’t planned to deal with a situation like this. When a ship’s down on the Moon, it can be spotted very quickly from one of the satellites-either Lagrange II, above Earthside, or Lagrange I, over Farside. But I doubt if they can help us now. As I said, we’ve probably gone down without leaving a trace.”

  “That’s hard to believe. When a ship sinks on Earth, it always leaves something behind—bubbles, oil slicks, floating wreckage.”

  “None of those apply to us. And I can’t think of any way we could send something up to the surface—however far away that is.”

  “So we just have to sit and wait.”

  “Yes,” agreed Pat. He glanced at the oxygen-reserve indicator. “And there’s one thing we can be sure of: we can only wait a week.”

  Fifty thousand kilometers above the Moon, Tom Lawson laid down the last of his photographs. He had gone over every square millimeter of the prints with a magnifying glass. Their quality was excellent; the electronic image intensifier, millions of times more sensitive than the human eye, had revealed details as clearly as if it were already daylight down there on the faintly glimmering plain. He had even spotted one of the tiny dust-skis—or, more accurately, the long shadow it cast in the earthlight. Yet there was no trace of Selene; the Sea was as smooth and unruffled as it had been before the coming of Man. And as it would be, in all probability, ages after he had gone.

  Tom hated to admit defeat, even in matters far less important than this. He believed that all problems could be solved if they were tackled in the right way, with the right equipment. This was a challenge to his scientific ingenuity; the fact that there were many lives involved was immaterial. Dr. Tom Lawson had no great use for human beings, but he did respect the Universe. This was a private fight between him and It.

  He considered the situation with a coldly critical intelligence. Now how would the great Holmes have tackled the problem? (It
was characteristic of Tom that one of the few men he really admired had never existed.) He had eliminated the open Sea, so that left only one possibility. The dust-cruiser must have come to grief along the coast or near the mountains, probably in the region known as—he checked the charts—Crater Lake. That made good sense; an accident was much more likely here than out on the smooth, unobstructed plain.

  He looked at the photographs again, this time concentrating on the mountains. At once, he ran into a new difficulty. There were scores of isolated crags and boulders along the edge of the Sea, any one of which might be the missing cruiser. Worse still, there were many areas that he could not survey at all, because his view was blocked by the mountains themselves. From his vantage point, the Sea of Thirst was far around the curve of the Moon, and his view of it was badly foreshortened. Crater Lake itself, for instance, was completely invisible to him, hidden by its mountain walls. That area could only be investigated by the dust-skis, working at ground level; even Tom Lawson’s godlike eminence was useless here.

  He had better call Earthside and give them his interim report.

  “Lawson, Lagrange II,” he said, when Communications had put him through. “I’ve searched the Sea of Thirst—there’s nothing in the open plain. Your boat must have gone aground near the edge.”

  “Thank you,” said an unhappy voice. “You’re quite sure of that?”

  “Absolutely. I can see your dust-skis, and they’re only a quarter the size of Selene.”

  “Anything visible along the edge of the Sea?”

  “There’s too much small-scale detail to make a search possible. I can see fifty—oh, a hundred—objects that might be the right size. As soon as the sun rises I’ll be able to examine them more closely. But it’s night down there now, remember.”

  “We appreciate your help. Let us know if you find anything else.”

  Down in Clavius City, the Tourist Commissioner heard Lawson’s report with resignation. That settled it; the next of kin had better be notified. It was unwise, if not impossible, to maintain secrecy any longer.