That meant the jet nozzles had to be made narrower and the steam hotter. But then drawbacks appeared. The narrower the nozzle, the more energy was lost in friction and turbulence. The hotter the steam, the more refractory the nozzle had to be and the shorter its life. The limit In that direction was quickly reached.
Then, since a given weight of water could move considerably more than its own weight under the narrow-nozzle conditions, it paid to be big. The bigger the water-storage space, the larger the size of the actual travel-head, even in proportion. So they started to make liners heavier and bigger. But then the larger the shell, the heavier the bracings, the more difficult the weldings, the more exacting the engineering requirements. At the moment, the limit in that direction had been reached also.
And then he had put his finger on what had seemed to him to be the basic flaw-the original unswervable conception that the fuel had to be placed inside the ship; the metal had to be built to encircle a million tons of water.
Why? Water did not have to be water. It could be ice, and ice could be shaped. Holes could be melted into it. Travel-heads and jets could be fitted into it. Cables could hold travel-heads and jets stiffly together under the influence of magnetic field-force grips.
Long felt the trembling of the ground he walked on. He was at the head of the fragment. A dozen ships were blasting in and out of sheaths carved into its substance, and the fragment shuddered under the continuing impact.
The ice didn't have to be quarried. It existed in proper chunks in the rings of Saturn. That's all the rings were-pieces of nearly pure ice, circling Saturn. So spectroscopy stated and so it had turned out to be. He was standing on one such piece now, over two miles long, nearly one mile thick. It was almost half a billion tons of water, all in one piece, and he was standing on it.
But now he was face to face with the realities of life. He had never told the men just how quickly he had expected to set up the fragment as a ship, but in his heart, he had imagined it would be two days. It was a week now and he didn't dare to estimate the remaining time. He no longer even had any confidence that the task was a possible one. Would they be able to control jets with enough delicacy through leads slung across two miles of ice to manipulate out of Saturn's dragging gravity?
Drinking water was low, though they could always distill more out of the ice. Still, the food stores were not in a good way either.
He paused, looked up into the sky, eyes straining. Was the object growing larger? He ought to measure its distance. Actually, he lacked the spirit to add that trouble to the others. His mind slid back to greater immediacies.
Morale, at, least, was high. The men seemed to enjoy being out Saturn-way. They were the first humans to penetrate this far, the first to pass the asteroids, the first to see Jupiter like a glowing pebble to the naked eye, the first to see Saturn-like that.
He didn't think fifty practical, case-hardened, shell-snatching Scavengers would take time to feel that sort of emotion. But they did. And they were proud.
Two men and a half-buried ship slid up the moving horizon as he walked.
He called crisply, “Hello, there!”
Rioz answered, “That you, Ted?”
“You bet. Is that Dick with you?”
“Sure. Come on, sit down. We were just getting ready to ice in and we were looking for an excuse to delay.”
“I'm not,” said Swenson promptly. “When will we be leaving, Ted?”
“As soon as we get through. That's no answer, is it?”
Swenson said dispiritedly. “I suppose there isn't any other answer.”
Long looked up, staring at the irregular bright splotch in the sky.
Rioz followed his glance. “What's the matter?”
For a moment, Long did not reply. The sky was black otherwise and the ring fragments were an orange dust against it. Saturn was more than three fourth below the horizon and the rings were going with it. Half a mile away a ship bounded past the icy rim of the planetoid into the sky, was orange-lit by Saturn-light, and sank down again.
The ground trembled gently.
Rioz, said, “Something bothering you about the Shadow?”
They called it that. It was the nearest fragment of the rings, quite close considering that they were at the outer rim of the rings, where the pieces spread themselves relatively thin. It was perhaps twenty miles off, a jagged mountain, its shape clearly visible.
“How does it look to you?” asked Long.
Rioz shrugged. “Okay, I guess. I don't see anything wrong.”
“Doesn't it seem to be getting larger?”
“Why should it?”
“Well, doesn't it?” Long insisted.
Rioz and Swenson stared at it thoughtfully.
“It does look bigger,” said Swenson.
“You're just putting the notion into our minds,” Rioz argued. “If it were bigger, it would be coming closer.”
“What's impossible about that?”
“These things are on stable orbits.”
“They were when we came here,” said Long. “There, did you feel that?”
The ground had trembled again.
Long said, “We've been blasting this thing for a week now. First, twenty-five ships landed on it, which changed its momentum right there. Not much, of course. Then we've been melting parts of it away and our ships have been blasting in and out of it-all at one end, too. In a week, we may have changed its orbit just a bit. The two fragments, this one and the Shadow, might be converging.”
“It's got plenty of room to miss us in.” Rioz watched it thoughtfully. “Besides, if we can't even tell for sure that it's getting bigger, how quickly can it be moving? Relative to us, I mean.”
“It doesn't have to be moving quickly. Its momentum is as large as ours, so that, however gently it hits, we'll be nudged completely out of our orbit, maybe in toward Saturn, where we don't want to go. As a matter of fact, ice has a very low tensile strength so that both planetoids might break up into gravel.”
Swenson rose to his feet “Damn it, if I can tell how a shell is moving a thousand miles away, I can tell what a mountain is doing twenty miles away.” He turned toward the ship.
Long didn't stop him.
Rioz said, “There's a nervous guy.”
The neighboring planetoid rose to zenith, passed overhead, began sinking. Twenty minutes later, the horizon opposite that portion behind which Saturn had disappeared burst into orange flame as its bulk began lifting again.
Rioz called into his radio, “Hey, Dick, are you dead in there?”
“I'm checking,” came the muffled response.
“Is it moving?” asked Long.
“Yes.”
“Toward us?”
There was a pause. Swenson's voice was a sick one. “On the nose, Ted. Intersection of orbits will take place in three days.”
“You're crazy!” yelled Rioz.
“I checked four times,” said Swenson.
Long thought blankly, What do we do now?
IX
Some of the men were having trouble with the cables. They had to be laid precisely; their geometry had to be very nearly perfect for the magnetic field to attain maximum strength. In space, or even in air, it wouldn't have mattered. The cables would have lined up automatically once the juice went on.
Here it was different. A gouge had to be plowed along the planetoid's surface and into it the cable had to be laid. If it were not lined up within a few minutes of arc of the calculated direction, a torque would be applied to the entire planetoid, with consequent loss of energy, none of which could be spared. The gouges then had to be redriven, the cables shifted and iced into the new positions.
The men plodded wearily through the routine.
And then the word reached them:
“All hands to the jets!”
Scavengers could not be said to be the type that took kindly to discipline. It was a grumbling, growling, muttering group that set about disassembling the jets of the
ships that yet remained intact, carrying them to the tail end of the planetoid, grubbing them into position, and stringing the leads along the surface.
It was almost twenty-four hours before one of them looked into the sky and said, “Holy jeepers!” followed by something less printable.
His neighbor looked and said, “I’ll be damned!”
Once they noticed, all did. It became the most astonishing fact in the Universe.
“Look at the Shadow!”
It was spreading across the sky life an infected wound. Men looked at it, found it had doubled its size, wondered why they hadn't noticed that sooner.
Work came to a virtual halt. They besieged Ted Long.
He said, “We can't leave. We don't have the fuel to see us back to Mars and we don't have the equipment to capture another planetoid. So we've got to stay. Now the Shadow is creeping in on us because our blasting has thrown us out of orbit. We've got to change that by continuing the blasting. Since we can't blast the front end any more without endangering the ship we're building, let's try another way.”
They went back to work on the jets with a furious energy that received impetus every half hour when the Shadow rose again over the horizon, bigger and more menacing than before.
Long had no assurance that it would work. Even if the jets would respond to the distant controls, even if the supply of water, which depended upon a storage chamber opening directly into the icy body of the planetoid, with built-in heat projectors steaming the propulsive fluid directly into the driving cells, were adequate, there was still no certainty that the body of the planetoid without a magnetic cable sheathing would hold together under the enormously disruptive stresses.
“Ready!” came the signal in Long's receiver.
Long called, “Ready!” and depressed the contact
The vibration grew about him. The star field in the visiplate trembled.
In the rearview there was a distant gleaming spume of swiftly moving ice crystals.
“It's blowing!” was the cry.
It kept on blowing. Long dared not stop. For six hours, it blew, hissing, bubbling, steaming into space; the body of the planetoid converted to vapor and hurled away.
The Shadow came closer until men did nothing but stare at the mountain in the sky, surpassing Saturn itself in spectacularity. Its every groove and valley was a plain scar upon its face. But when it passed through the planetoid's orbit it crossed more than half a mile behind its then position.
The steam jet ceased.
Long bent in his seat and covered his eyes. He hadn't eaten in two days. He could eat now, though. Not another planetoid was close enough to interrupt them, even if it began an approach that very moment
Back on the planetoid's surface, Swenson said, “All the time I watched that damned rock coming down, I kept saying to myself, 'This can't happen. We can't let it happen.'”
“Hell,” said Rioz, “we were all nervous. Did you see Jim Davis? He was green. I was a little jumpy myself.”
“That's not it. It wasn't just-dying, you know. I was thinking-I know it's funny, but I can't help it-I was thinking that Dora warned me I'd get myself killed, she'll never let me hear the last of it. Isn't that a crummy sort of attitude at a time like that?”
“Listen,” said Rioz, “you wanted to get married, so you got married. Why come to me with your troubles?”
X
The flotilla, welded into a single unit, was returning over its mighty course from Saturn to Mars. Each day it flashed over a length of space it had taken nine days outward. Ted Long had put the entire crew on emergency. With twenty-five ships embedded in the planetoid taken out of Saturn's rings and unable to move or maneuver independently, the co-ordination of their power source into unified blasts was a ticklish problem. The jarring that took place on the first day of travel nearly shook them out from under their hair.
That, at least, smoothed itself out as the velocity raced upward under the steady thrust from behind. They passed the one-hundred-thousand-mile-an-hour mark late on the second day, and climbed steadily toward the million-mile mark and beyond.
Long's ship, which formed the needle point of the frozen fleet, was the only one which possessed a five-way view of space. It was an uncomfortable position under the circumstances. Long found himself watching tensely, imagining somehow that the stars would slowly begin to slip backward, to whizz past them, under the influence of the multi-ship's tremendous rate of travel.
They didn't, of course. They remained nailed to the black backdrop, their distance scorning with patient immobility any speed mere man could achieve.
The men complained bitterly after the first few days. It was not only that they were deprived of the space-float. They were burdened by much more than the ordinary pseudo-gravity field of the ships, by the effects of the fierce acceleration under which they were living. Long himself was weary to death of the relentless pressure against hydraulic cushions.
They took to shutting off the jets thrusts one hour out of every four and Long fretted.
It had been just over a year that he had last seen Mars shrinking in an observation window from this ship, which had then been an independent entity. What had happened since then? Was the colony still there?
In something like a growing panic, Long sent out radio pulses toward Mars daily, with the combined power of twenty-five ships behind it. There was no answer. He expected none. Mars and Saturn were on opposite sides of the Sun now, and until he mounted high enough above the ecliptic to get the Sun well beyond the line connecting himself and Mars, solar interference would prevent any signal from getting through.
High above the outer rim of the Asteroid Belt, they reached maximum velocity. With short spurts of power from first one side jet, then another, the huge vessel reversed itself. The composite jet in the rear began its mighty roaring once again, but now the result was deceleration.
They passed a hundred million miles over the Sun, curving down to intersect the orbit of Mars.
A week out of Mars, answering signals were heard for the first time, fragmentary, ether-torn, and incomprehensible, but they were coming from Mars. Earth and Venus were at angles sufficiently different to leave no doubt of that
Long relaxed. There were still humans on Mars, at any rate.
Two days out of Mars, the signal was strong and dear and Sankov was at the other end.
Sankov said, “Hello, son. It's three in the morning here. Seems like people have no consideration for an old man. Dragged me right out of bed.”
“I'm sorry, sir.”
“Don't be. They were following orders. I'm afraid to ask, son. Anyone hurt? Maybe dead?”
“No deaths, sir. Not one.”
“And-and the water? Any left?”
Long said, with an effort at nonchalance, “Enough.”
“In that case, get home as fast as you can. Don't take any chances, of course.”
“There's trouble, then.”
“Fair to middling. When will you come down?”
“Two days. Can you hold out that long?”
“Ill hold out.”
Forty hours later Mars had grown to a ruddy-orange ball that filled the ports and they were in the final planet-landing spiral.
“Slowly,” Long said to himself, “slowly.” Under these conditions, even the thin atmosphere of Mars could do dreadful damage if they moved through it too quickly.
Since they came in from well above the ecliptic, their spiral passed from north to south. A polar cap shot whitely below them, then the much smaller one of the summer hemisphere, the large one again, the small one, at longer and longer intervals. The planet approached closer, the landscape began to show features.
“Prepare for landing!” called Long.
ELEVEN
Sankov did his best to look placid, which was difficult considering how closely the boys had shaved their return. But it had worked out well enough.
Until a few days ago, he had no sure knowledge that they had surv
ived. It seemed more likely-inevitable, almost-that they were nothing but frozen corpses somewhere in the trackless stretches from Mars to Saturn, new planetoids that had once been alive.
The Committee had been dickering with him for weeks before the news had come. They had insisted on his signature to the papers for the sake of appearances. It would look like an agreement, voluntarily and mutually arrived at. But Sankov knew well that, given complete obstinacy on his part, they would act unilaterally and be damned with appearances. It seemed fairly certain that Hilder's election was secure now and they would take the chance of arousing a reaction of sympathy for Mars.
So he dragged out the negotiations, dangling before them always the possibility of surrender.
And then he heard from Long and concluded the deal quickly.
The papers had lain before him and he had made a last statement for the benefit of the reporters who were present.
He said, “Total imports of water from Earth are twenty million tons a year. This is declining as we develop our own piping system. If I sign this paper agreeing to an embargo, our industry, will be paralyzed, any possibilities of expansion will halt. It looks to me as if that can't be what's in Earth's mind, can it?”
Their eyes met his and held only a hard glitter. Assemblyman Digby had already been replaced and they were unanimous against him.
The Committee Chairman impatiently pointed out, “You have said all this before.”
“I know, but right now I'm kind of getting ready to sign and I want it clear in my head. Is Earth set and determined to bring us to an end here?”
“Of course not. Earth is interested in conserving its irreplaceable water supply, nothing else.”