Authors: Arthur C Clarke
That was some consolation, at any rate. They had air and food for many days—all tractors carried a large emergency reserve—and the Observatory knew their approximate position. But before long the Observatory might have trouble of its own, and would be unable to bother about them…
Jamieson re-started the motor, and the sturdy vehicle started to butt its way forward again through the dry quicksand that enveloped them. It was impossible to tell how much progress they were making, and Wheeler dared not imagine what would happen if the motors failed. The caterpillar treads were grinding at the rock beneath them, and the whole tractor shook and groaned under the intolerable load.
It was almost an hour before they were certain they were getting somewhere. The floor of the tractor was definitely tilting upward, but there was no way of telling how far below the quasi-liquid surface they were still submerged. They might emerge at any moment into the blessed light of day—or they might have a hundred meters still to traverse at this snail-like pace.
Jamieson was stopping for longer and longer intervals, which might reduce the strain on the engine but did nothing to reduce that on the passengers. During one of these pauses Wheeler asked him outright what they should do if they could get no further.
"We've only two possibilities," Jamieson answered. "We can stay here and hope to be rescued—which won't be as bad as it sounds, since our tracks will make it obvious where we are. The other alternative is to go out."
"What! That's impossible!"
"Not at all. I know a case where it's been done. It would be rather like escaping from a sunken submarine."
"It's a horrible thought—trying to swim through this stuff."
"I was once caught in a snowdrift when I was a kid, so I can guess what it would be like. The great danger would be losing your direction and floundering around in circles until you were exhausted. Let's hope we don't have to try the experiment."
It was a long time, Wheeler decided, since he had heard a bigger understatement than that.
The driving cab emerged above the dust level about an hour later, and no men could ever have greeted the sun with such joy. But they had not yet reached safety; though Ferdinand could make better speed as the resistance slackened, there might still be unsuspected depths ahead of them.
Wheeler watched with fascinated repulsion as the horrible stuff eddied past the tractor. At times it was quite impossible to believe that they were not forcing their way through a liquid, and only the slowness with which they moved spoiled the illusion. He wondered if it was worth suggesting that in future Caterpillars have better streamlining to improve their chances in emergencies like this. Who would ever have dreamed, back on Earth, that
that
sort of thing might be necessary?
At last Ferdinand crawled up to the security of the dry land, which, after all, was no drier than the deadly lake from which they had escaped. Jamieson, almost exhausted by the strain, slumped down across the control panel. The reaction had left Wheeler shaken and weak, but he was too thankful to be out of danger to let that worry him.
He had forgotten, in the relief of seeing sunlight again, that they had left Project Thor three hours ago, and had covered less than twenty kilometres.
Even so, they might have made it. But they had just started on their way again, and were crawling over the top of a quite gentle ridge, when there was a scream of tearing metal and Ferdinand tried to spin round in a circle. Jamieson cut the motor instantly and they came to rest broadside-on to their direction of motion.
"And that," said Jamieson softly, "is most definitely that. But I don't think we're in a position to grumble. If the starboard transmission had sheared while we were still in that dust-bowl—" He didn't finish the sentence, but turned to the observation port that looked back along their trail. Wheeler followed his gaze.
The dome of Project Thor was still visible on the horizon. Perhaps they had already strained their luck to the utmost—but it would have been nice could they have put the protecting curve of the Moon clear between themselves and the unknown storms that were brewing there.
Even today, little has ever been revealed concerning the weapons used in the Battle of Pico. It is known that missiles played only a minor part in the engagement. In space warfare, anything short of a direct hit is almost useless, since there is nothing to transmit the energy of a shock wave. An atom bomb exploding a few hundred meters away can cause no blast damage, and even its radiation can do little harm to well-protected structures. Moreover, both Earth and the Federation had effective means of diverting ordinary projectiles.
Purely non-material weapons would have to play the greatest role. The simplest of these were the ion-beams, developed directly from the drive-units of spaceships. Since the invention of the first radio tubes, almost three centuries before, men had been learning how to produce and focus ever more concentrated streams of charged particles. The climax had been reached in spaceship propulsion with the so-called "ion rocket," generating its thrust from the emission of intense beams of electrically charged particles. The deadliness of these beams had caused many accidents in space, even though they were deliberately defocused to limit their effective range.
There was, of course, an obvious answer to such weapons. The electric and magnetic fields which produced them could also be used for their dispersion, converting them from annihilating beams into a harmless, scattered spray.
More effective, but more difficult to build, were the weapons using pure radiation. Yet even here, both Earth and the Federation had succeeded. It remained to be seen which had done the better job—the superior science of the Federation, or the greater productive capacity of Earth.
Commodore Brennan was well aware of all these factors as his little fleet converged upon the Moon. Like all commanders, he was going into action with fewer resources than he would have wished. Indeed, he would very much have preferred not to be going into action at all.
The converted liner
Eridanus
and the largely rebuilt freighter
Lethe
—once listed in Lloyd's register as the
Morning Star
and the
Rigel
—would now be swinging in between Earth and Moon along their carefully plotted courses. He did not know if they still had the element of surprise. Even if they had been detected, Earth might not know of the existence of this third and largest ship, the
Acheron.
Brennan wondered what romantic with a taste for mythology was responsible for these names—probably Commissioner Churchill, who made a point of emulating his famous ancestor in as many ways as he possibly could. Yet they were not inappropriate. The rivers of Death and Oblivion—yes, these were things they might bring to many men before another day had passed.
Lieutenant Curtis, one of the few men in the crew who had actually spent most of his working life in space, looked up from the communications desk.
"Message just picked up from the Moon, sir. Addressed to us."
Brennan was badly shaken. If they had been spotted, surely their opponents were not so contemptuous of them that they would freely admit the fact! He glanced quickly at the signal, then gave a sigh of relief.
OBSERVATORY TO FEDERATION. WISH TO REMIND YOU OF EXISTENCE IRREPLACEABLE INSTRUMENTS PLATO. ALSO ENTIRE OBSERVATORY STAFF STILL HERE. MACLAURIN. DIRECTOR.
"Don't frighten me like that again, Curtis," said the commodore. "I thought you meant it was beamed at me. I'd hate to think they could detect us this far out."
"Sorry, sir. It's just a general broadcast. They're still sending it out on the Observatory wavelength."
Brennan handed the signal over to his operations controller, Captain Merton.
"What do you make of this? You worked there, didn't you?"
Merton smiled as he read the message.
"Just like Maclaurin. Instruments first, staff second. I'm not too worried. I'll do my damnedest to miss him. A hundred kilometres isn't a bad safety margin, when you come to think of it. Unless there's a direct hit with a stray, they've nothing to worry about. They're pretty well dug in, you know."
The relentless hand of the chronometer was scything away the last minutes. Still confident that his ship, encased in its cocoon of night, had not yet been detected, Commodore Brennan watched the three sparks of his fleet creep along their appointed tracks in the plotting sphere. This was not a destiny he had ever imagined would be his—to hold the fate of worlds within his hands.
But he was not thinking of the powers that slumbered in the reactor banks, waiting for his command. He was not concerned with the place he would take in history, when men looked back upon this day. He only wondered, as had all who had ever faced battle for the first time, where he would be this same time tomorrow.
Less than a million kilometres away, Carl Steffanson sat at a control desk and watched the image of the sun, picked up by one of the many cameras that were the eyes of Project Thor. The group of tired technicians standing around him had almost completed the equipment before his arrival; now the discriminating units he had brought from Earth in such desperate haste had been wired into the circuit.
Steffanson turned a knob, and the sun went out. He flicked from one camera position to another, but all the eyes of the fortress were equally blind. The coverage was complete.
Too weary to feel any exhilaration, he leaned back in his seat and gestured toward the controls.
"It's up to you now. Set it to pass enough light for vision, but to give total rejection from the ultra-violet upward. We're sure none of their beams carry any effective power much beyond a thousand Angstroms. They'll be very surprised when all their stuff bounces off. I only wish we could send it back the way it came."
"Wonder what we look like from outside when the screen's on?" said one of the engineers.
"Just like a perfectly reflecting mirror. As long as it keeps reflecting, we're safe against pure radiation. That's all I can promise you."
Steffanson looked at his watch.
"If Intelligence is correct, we have about twenty minutes to spare. But I shouldn't count on it."
"At least Maclaurin knows where we are now," said Jamieson as he switched off the radio. "But I can't blame him for not sending someone to pull us out."
"Then what do we do now?"
"Get some food," Jamieson answered, walking back to the tiny galley. "I think we've earned it, and there may be a long walk ahead of us."
Wheeler looked nervously across the plain, to the distant but all too clearly visible dome of Project Thor. Then his jaw dropped and it was some seconds before he could believe that his eyes were not playing tricks on him.
"Sid!" he called. "Come and look at this!"
Jamieson joined him at a rush, and together they stared out toward the horizon. The partly shadowed hemisphere of the dome had changed its appearance completely. Instead of a thin crescent of light, it now showed a single dazzling star, as though the image of the sun was being reflected from a perfectly spherical mirror surface.
The telescope confirmed this impression. The dome itself was no longer visible; its place seemed to have been taken by this fantastic silver apparition. To Wheeler it looked exactly like a great blob of mercury sitting on the skyline.
"I'd like to know how they've done that," was Jamieson's un-excited comment. "Some kind of interference effect, I suppose. It must be part of their defence system."
"We'd better get moving," said Wheeler anxiously. "I don't like the look of this. It feels horribly exposed up here."
Jamieson had started throwing open cupboards and pulling out stores. He tossed some bars of chocolate and packets of compressed meat over to Wheeler.
"Start chewing some of this," he said. "We won't have time for a proper meal now. Better have a drink as well, if you're thirsty. But don't take too much—you'll be in that suit for hours, and these aren't luxury models."
Wheeler was doing some mental arithmetic. They must be about eighty kilometres from base, with the entire rampart of Plato between them and the Observatory. Yes, it would be a long walk home, and they might after all be safer here. The tractor, which had already served them so well, could protect them from a good deal of trouble.
Jamieson toyed with the idea, but then rejected it. "Remember what Steffanson said," he reminded Wheeler. "He told us to get underground as soon as we could. And he must know what he's talking about."
They found a crevasse within fifty meters of the tractor, on the slope of the ridge away from the fortress. It was just deep enough to see out of when they stood upright, and the floor was sufficiently level to lie down. As a slit trench, it might almost have been made to order, and Jamieson felt much happier when he had located it.
"The only thing that worries me now," he said, "is how long we may have to wait. It's still possible that nothing will happen at all. On the other hand, if we start walking we may be caught in the open away from shelter."
After some discussion, they decided on a compromise. They would keep their suits on, but would go back and sit in Ferdinand where at least they would be comfortable. It would take them only a few seconds to get to the trench.