Cold as Ice

Cold as Ice

Charles Sheffield

This is a work of fiction. All the characters and events portrayed in this book are fictional, and any resemblance to real people or incidents is purely coincidental.
Copyright © 1992 by Charles Sheffield
All rights reserved, including the right to reproduce this book or portions thereof in any form.
Baen Publishing Enterprises
P.O. Box 1403
Riverdale, NY 10471
www.baen.com
ISBN: 978-1-61824-056-9

TO ARTHUR CLARKE,
FOR THE LOAN OF EUROPA;
AND TO THE
VOYAGER
TEAM,
FOR ALL THOSE GREAT PICTURES.

PROLOGUE
2067 A.D.: Rejoice! the War is Over

Every war begins with a first encounter, a first blow, a first casualty. That is the shot heard 'round the world.

But in every war there must also be a last victim. And the event that takes that victim can happen after the combat is officially ended.

The
Pelagic
was a deep-space freighter, hurriedly converted for passenger transport. Designed to creep ore-laden from asteroid mines to the great refineries in low orbit about Earth or Mars, the ship had a maximum acceleration of less than a quarter gravity. The Seeker that pursued her could sustain five gees, or boost briefly at a hundred.

The presence of the pursuer had been detected in a routine scan for Belt debris not listed in the data banks. Of the four people in the control room following the emergency call, only Vernor Perry, the navigation officer, had accepted what the Seeker's steady approach meant.

"I know we can't outrun it." Loring Sheer, the chief engineer, was still arguing. "Why should we
need
to? You heard the radio messages from Earth. The war is
over
!"

"Vern? What do you say to that?" Mimi Palance was the captain, hurriedly appointed when the refugee ship left the mid-sized asteroid of Mandrake. She was a habitat designer, and she was having trouble in adjusting to the idea of space command.

Vernor Perry looked stupefied. He was the one who had called them to the control room. He knew more about Seekers than anyone else on board. He also knew that he was dead. All discussion was pointless.

"Vera!" said Palance again, in a sharper tone.

Perry roused himself. "It makes no difference if the war is over or not. Seekers are smart missiles, but they were built without a cancel mode. Once targeted, they can't be changed."

"But what makes you sure that
we
are the target?" asked the personnel officer. It was her first time in space since the war began, and Mary Vissuto was still bewildered by the sudden order to flee from Mandrake. "Why mightn't the target be another ship, or even a colony?"

"Probabilities." Perry pointed to a three-D display with the
Pelagic
as its moving center. "There's no other ship or artificial structure within five million kilometers. That Seeker is heading directly toward us. There's no reasonable chance that it's aiming for anything else."

"So what can we do to escape it?"

Perry shrugged.

"That's no answer, Vern," said Palance. And, sharply again when he did not reply, "Come on, man. We have four adults and fifteen children on board. I agree, we can't outrun a Seeker. But what about a course change?"

"Useless."
We're dead. Why are you bothering me?
"I tell you, a Seeker is
smart.
It's already observing us, with all of its sensors. If we change course, it will compute a revised contact trajectory. If we turn our power off, it will track us by our thermal signature. The
Pelagic
is hotter than any natural body in the Belt. It has to be, or we'd all be frozen."

"Then if we can't run away, can we hide? Suppose we head for an asteroid and park behind it."

"The Seeker will follow us. We can't run, and we can't hide." But even as he spoke, a flicker of an idea crossed Perry's frozen mind.

"What, Vern?" Mimi Palance had seen the change of expression.

"We may be able to hide—for just a while. Don't get your hopes up, though. We can't
escape.
But we might buy a little time." Perry went over to the control console and called up the banks of solar-system ephemerides.

"I thought you just said that we
couldn't
hide. So why are you looking at asteroids?" Loring Sheer had been trying to adjust to the idea of imminent death, but now the engineer was confused again.

"We can't hide behind
one.
What we need for breathing space is a
cluster.
I've got the computer looking for one we can reach before the Seeker reaches us." He checked the missile's progress. "Luckily, it's in no hurry—it knows we can't get away." He pressed the compute key. "Hold your breath."

"What are you calculating, Vern?" Mary Vissuto had been too busy on Mandrake with the children and with her own work to pay much attention to the celestial mechanics of the Belt.

"Asteroid groups. The asteroids move all the time relative to each other." And when Mary still showed no sign of understanding, "They move, you see, but the law of averages means that there have to be temporary clusters, continually forming and dissolving. The trick is to find one near enough to do us some good. Then we move over and snuggle up into the middle of the group."

He did not take time to explain the tricky part of what he was doing. The bodies of the Asteroid Belt ranged in size from Ceres, a giant by asteroid standards at seven hundred and fifty kilometers, down to free-falling mountains and on to the pea-sized and smaller pebbles. Everything from worlds to sand grains moved in its own complicated orbit, defined by the gravitational forces of sun and planets, by solar wind and radiation pressure, and by asteroid interactions.

Vern's first task was to choose reasonable size limits. He had on file the orbit parameters for every Belt body of more than fifty meters in diameter, and he had set the required number of bodies to one thousand, with a cluster radius of five hundred kilometers. If the computer could find nothing that matched those requirements, he would have to decrease the number of bodies in the cluster or increase the permitted cluster radius. Each of those options would make it more difficult for the
Pelagic
to hide. And the hiding place would be temporary, whatever he did. The Seeker would patiently search every body of a cluster until it again encountered the unique signature of the
Pelagic.

The other two in the control room had not needed Perry's explanation to know what he was doing. Their eyes were fixed on the displays. "It's found some," said Palance as the computation ended. "Four of them!"

Perry shrugged. "Yeah, but look at the distances. We can forget the first three—the Seeker would catch us before we got there. It's number four, or nothing."

"That cluster's not even close to our present trajectory." Sheer was peering at the tabulation. "We'd have to burn all the fuel we've got to make that course change."

"You'll never find a better use for it." Mimi Palance had already made up her mind. "Vern, give me a flight path."

"Doing it." Perry was at the console. Hope was the biggest delusion, but what else was there to do? "Loring, make sure you're ready for full acceleration. I'm going to assume that you can squeeze out a quarter gee."

"You'll be lucky." But Loring Sheer was looking better as he hurried out. Something to do,
anything
to do. Even if he blew the engines apart, that was better than sitting around watching the approach of the Seeker.

"A quarter gee!" protested Mary Vissuto. "We haven't had a tenth of that since we left Mandrake. The cabins and galley aren't ready for it."

"They'd better be," said Perry. "In about two minutes. I'm programming for maximum thrust as soon as Sheer can give it to us."

"We'll never get things tied down in time." But Mary, too, was hurrying out, leaving Palance and Perry alone in the control room.

"So we go sit in the middle of the cluster." Perry spoke in a dry, controlled voice, as though they were discussing some academic problem of orbital rendezvous. At the same time, he was fine-tuning the trajectory, seeking a region where the cluster bodies were converging. "What then, Mimi? Loring and Mary still don't understand. They think this gives us a chance. It doesn't. It gives us a short reprieve. There's no way that the
Pelagic
can escape a Seeker."

"I know. We're going to die. I didn't accept that ten minutes ago, I do now. But I
don't
accept it for the children. They're special. We have to come up with an idea, Vern. And we have to do it quick. Get your brain in gear."

The control sequence took over. The engines fired. The
Pelagic
accelerated its ungainly bulk toward the random assembly of rock fragments that comprised the chosen cluster. Far behind, taking course changes in its stride and closing steadily on the bigger ship, the deadly needle of the Seeker followed every move.

* * *

When the group reconvened in the control room six hours later, Mimi had herself and the meeting under better control. She took no credit for that. Loring Sheer and Mary Vissuto had come to grips with unpleasant reality, while Vern Perry was admitting that impending death did not remove the obligation to think.

"Vern." She nodded her head at the navigation officer. "Status summary, please."

"Our physical location has changed, but not our situation." Perry already had the displays he needed on file. "That's us." A blue point winked on the screen. "We're nicely tucked away behind a one-kilometer rock, and I'm going to keep us there. These fourteen other bodies"—more winking lights—"are available if we want to do some dodging. We're safe for twenty-four hours unless the Seeker changes its operating plan. I don't see why it should. Here it is." A red point of light appeared. "It knows where we are, and the Doppler from its radar signals shows that it's closing at a constant rate."

He turned from the console. "The bad news we already know. We can't run away, because we have no fuel left. Even if we could, the Seeker is fast enough to catch us and run rings round us."

"All right." Mimi Palance turned to Sheer. "The
Pelagic
is stuck here. What about other transport?"

"There's one lifeboat. We could all get into it, and we might even be able to fly somewhere before we ran out of air. But we wouldn't be given the chance. A Seeker can recognize a lifeboat as well as it can a ship, and it would see our drive go on. It would tackle the
Pelagic,
then come after us—or maybe the other way around. Either way, it would make no difference. We can't get anywhere using the lifeboat."

"So cross that one off." Mimi was aware of the clock. Any actions they might take were less likely to succeed as the Seeker came closer and the resolution of its sensors improved. "All right. Life support and habitats, that's my area. Not good. We have nine single-person pods. Self-contained life-support system on each one, but no thrust capability. Nine pods, and nineteen of us. Bad arithmetic. Mary? Ideas?"

"Nine of the children are two years old or less. Can you double up, put two to a pod?"

"No." Mimi Palance did not elaborate. She knew why that was impossible, as Mary should have known too. "If we put kids on the pods, only nine can go. And they have to be the youngest. They're the smallest, and the pods can keep them alive the longest. The bigger ones . . . stay here with us."

She paused and swallowed. The others could not look at her. They knew that although each of them had a child on board under two, Mimi Palance's only child was a boy approaching seven. He would stay with her on the
Pelagic.

And die with her,
thought Vernor Perry.
Just like the rest of us.
But all he said was, "Won't work."

"Why not? We can do a ballistic launch—throw them out of the
Pelagic.
No thrust from the pods for the Seeker to track. It will think they are bits of space junk associated with the cluster. I'm sure the Seeker doesn't have any better list of small rocks than we do, and there are thousands around here that we don't have in the data bank."

"That's not the problem." Perry hated to dash hopes, but there was no value to fantasy. "Sure, there would be no thrust to track, no deviation from free-fall to observe. But that's only one way that the Seeker hunts. The pods have to be kept above ambient temperature if you want the kids to survive. So the Seeker will find them in just the way it's going to find the
Pelagic
—because of a thermal signal far above background."

"Loring? Any comment? Any ideas?"

"No. Vern's right. The Seeker will detect and destroy the pods." The engineer was silent for a few seconds. "Unless . . ."

"Come on, Loring. Quick! We don't have time to dawdle."

"Well, this is half-baked. But we have liquid helium on board. Not a lot of it, but the I/R sensor detectors need cooling way down, and we use it for that. Suppose we put the kids inside the pods, as many of them as will fit, and then we blow a liquid-helium spray onto the
outside
of the pods. That could bring the skin temperature down to ambient, the same as the rest of the rocks in the cluster. It would take some calculation of latent heats and heat transfer, but I can hack that out pretty quick. And
then
we eject the pods from the
Pelagic
while we're in the shadow of one of the bigger asteroids . . . and hope the pods get far enough away before they heat up again because of the children inside. It's our best bet. Vern?"