Half Life

Half Life

by Hal Clement
Half Life

Half Life

by Hal Clement

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Overview

In about two hundred years, the human race on Earth is perhaps facing extinction due to the rapid evolution of disease. A crew of young men and women travel to the moons of Saturn, to Titan, to investigate the biochemistry of the pre-life conditions there in the slim hope of discovering something that might save Earth. The whole story runs at high-speed, as they race to find answers across the surface of an alien landscape with death close behind . . . and gaining.



At the Publisher's request, this title is being sold without Digital Rights Management Software (DRM) applied.


Product Details

ISBN-13: 9781466836815
Publisher: Tor Publishing Group
Publication date: 06/15/2000
Sold by: Macmillan
Format: eBook
Pages: 256
File size: 763 KB

About the Author

Hal Clement (1922-2003) is a Science Fiction Writers of America Grand Master, and the author of the novels Half Life, Heavy Planet and the classic Mission of Gravity.
Hal Clement (1922-2003) is a Science Fiction Writers of America Grand Master, and the author of the novels Half Life, Heavy Planet and the classic Mission of Gravity.

Read an Excerpt

1

SPOT

It was bad timing, not too surprisingly for a random event. His Mollweide screen was offering one of its occasional, brief, irregularly presented views of Sergeant Gene Belvew's real surroundings. These consisted of his personal quarantined suite in the Station seven hundred kilometers above Titan's surface, and showed nothing surprising at all. It cut him off for little more than a second from the scenes provided by Oceanus's cameras deep in the atmosphere below, but in that second the pipe stall occurred.

It would, a less conscious level of his mind reflected. He didn't believe in a literal, unqualified Murphy's Law, which was strictly for near-civilians like Ludmilla Anden. She was actually a corporal, one of the few people still alive in the Saturn system who didn't outrank him, and for reasons he didn't know himself he tended quite unjustly to regard her as not properly military.

A scientist of any rank should understand the Law of Selective Observation, which tradition, flexible as ever in its details, now attributed to one Murphy. If his engines had chosen any other time to flame out he would have seen it coming, forestalled it easily without conscious thought, and forgotten it promptly as unimportant. As it was, his first warning was the waldo suit's nonvisual input, which kept him in touch with his aircraft even when he could see nothing but the walls, furniture, and equipment actually around him.

Being in two places at once was no longer a logical impossibility but a familiar nuisance.

The suit administered a sharp twinge almost simultaneously to both his elbows. A moment later, when he could see Titan again, thrust was gone and accelerometers showed that Oceanus was slowing sharply in the dense atmosphere. His reflexes had already operated, of course, only slightly later than they would have from a visual stimulus; but the trifle-made a frightening difference.

Belvew was an excellent pilot except for his tendency to take occasional chances. The aircraft had practically no reaction mass in its tanks, mainly because of the pilot's eagerness to get .the seismic lines dropped without wasting time tanking up, so shifting to rocket mode would be futile. It had been obvious to everyone that trying to finish the current line with no thrust backup was silly, but Belvew wasn't the only person impatient for data. The thunderhead over Lake Carver had, however, practically forced itself on his attention, convincing him that he could pick up juice with very little delay after all, and he had been just implementing his decision to refill after all when it happened.

The big satellite's gravity, which his body in orbit couldn't feel any more than it could the ramjet's deceleration, was feeble; if the craft had slowed too much, even the vertical dive he had promptly entered wouldn't get him back to ram speed from his present altitude. Diving into the surface would not injure him physically—the waldo's feedback didn't go that far—but would still be a bad tactical mistake. Ramjets, while they were grown products, pseudolife like practically every other piece of modern equipment, could not be picked from trees.

Not that there were trees this far from the Sun. The aircraft were not even single pseudoorganisms, but assemblages of more than a thousand separately grown modules. Replacement would not be impossible, but would be lengthy and difficult and would complicate planning. Carla—Lieutenant lePing—did have two more nearly assembled, and plenty of modules were growing, but like most of the crew she was not always able to work.

For increasingly worrisome moments the tension and airspeed mounted as Gene's elbows stayed sore. Then ram flow resumed simultaneously in both pipes and the speed of his dive abruptly increased with the restored thrust. Still reflexively he pulled out of the dive, very carefully to avoid a secondary stall.

In level flight at last, with fully a hundred meters of air still below him, he put his nose—his own, not the ramjet's—more deeply into the face cup of his suit and moved his head slightly. This ran the screen through its preset half dozen most-likely-useful vision frequencies. He was already pretty sure what had caused the stall, but pilot's common sense agreed with basic scientific-military procedure in demanding that he check.

Yes, he was still in the updraft; the screen displayed the appropriate false colors all around him, and the waldo, which was also an environment suit, and therefore had been designed not to interfere with his own breathing system by using olfactory codes, was reporting the excess methane and consequent lowered air density as a set of musical tones. As usual, there had been no one but himself to blame.

He'd been driving just a little too slowly, trying to get a good look below while filling the mass tanks, and a perfectly ordinary but random and mathematically unpredictable drop in the density of the rising air had raised the impact pressure needed by the jets. He could have seen it coming, but if the waldo hadn't been backing up the interrupted visual sensors he'd have learned too late and with probably much less than a hundred meters leeway.

No point thinking about that.

"What happened, Sarge? Or shouldn't I ask?" Barn Inger, Belvew's coranker and usual flying partner, didn't bother to identify himself; only twenty-one people were left of the original crew, and there were no strange voices. As Belvew's copilot, a task fitted in among many other demands on his attention, one of Inger's regular duties was to check with Gene vocally or in any other way appropriate whenever something unexpected occurred in flight; the "shouldn't I ask" was merely a standard courtesy. Few people enjoyed admitting mistakes, however important they might be as data. The terminally ill people who formed a much larger fraction of the Titan crew than of Earth's rapidly shrinking population were often quite touchy about such things.

"I rode too close to stall. It's all right now," Belvew answered.

"Use anything from the tanks?" The question also was pure courtesy; like everyone else, Inger had repeaters for Oceanus's instrument output in his own quarters. Nearly anyone could have taken over control of the jet within seconds of realizing the need. Inger was trying to make the slip look like an everyday incident, to be passed over casually.

"Nothing to use. There was enough room to dive-start." Belvew did not mention just how little spare altitude he had had, and Inger didn't really need to ask. Because of the constant possibility of having to start flying with no notice, everyone kept as conscious as other duties allowed of current aerial activities.

"You're still over Carver. You could have put down and tanked up from the lake." This was quite true, but neither speaker mentioned why that option had been passed without conscious thought. Both knew perfectly well; Inger's stress on the "could" had been as close to being specific about it as either cared to go. He changed to a neutral subject.

"You seem to have the fourth leg about done."

Belvew made no answer for a moment; he was spiraling upward to start another pass through the droplet-rich up-draft, at a safer altitude this time. Mass was needed in his tanks as soon as possible, and he was now prepared to accept the lower concentration to be found higher up, and to budget the time to get there and make the extra run or two that would be needed. Haste hadn't paid, and had almost presented a very large bill. No one argued, most were relieved at the decision, and Gene was the pilot anyway.

"Not quite," he finally answered absently.

In visible light frequencies his target looked exactly like an earthly thunderhead. There was even lightning, in spite of the nonpolar composition of the droplets, and Belvew faced the piloting task of making collection runs through it at a speed high enough to prevent another ram stall but low enough to avoid turbulence damage to his airframe.

"Not quite," he repeated at last. "But I still have enough cans to finish Four and most of Five. I hope all the ones I've dropped so far work. It'd be a pity to have to go back just to make replacements. There's too much else to do." He fell silent again as the waldo began pressing his body at various points, indicating that Oceanus was entering turbulence. His fingers, shoulders, knees, elbows, tongue, and toes exerted delicate pressure, now this way, now that, on parts of the suit's lining, answering the thumps he could feel and forestalling the ones the vision screen let him anticipate. For nearly two minutes the aircraft jounced its way through the vertical currents, and as the turbulence eased off and the air around his viewers cleared, the pilot gave a happy grunt. He would have nodded his head in satisfaction, but that would have operated too many inappropriate controls.

"A respectable bite. Nine or ten more runs at this height should give us takeoff or orbit mass."

"Or a hundred or so stall recoveries," his official buddy couldn't help adding.

Belvew let the remark lie, and two or three minutes passed before anyone else spoke. All not otherwise too absorbed were reading for themselves the rise of tank levels as Oceanus's collectors gulped Titanian air, spun the hydrocarbon fog drops out of it, stored the liquid, and vented the remaining nearly pure nitrogen to the atmosphere. Even Status watched, but used only current-log memory, which would be routinely edited and wiped of nonessentials each Titan orbit.

"There's another odd surface patch a little east of Carver," Maria Collos's voice came at length, as the main tanks neared the seven-tenths mark. "It wouldn't take us very far off plan to look at it before we start Leg Five." She, too, would have been glad of seismic data—her growing maps showed a lot of topography in need of explanation—but was willing to pause for other information if the time cost was small enough.

"Like the earlier ones, or something really new?" asked Belvew.

"Can't tell for sure in long waves. It could be just another bit of melted tar, if that's what they're made of. It's the biggest so far, but even if that's all, we're getting enough of the things to need explanation."

"One would need explanation!" snapped Arthur Goodall, the highest-ranking and—excusably because of the ceaseless pain of synapse amplification syndrome—usually least patient of the group. "I can see and so can you how polymer tars formed up in sunlight would settle out of the air as dust at this temperature. I can see dust getting piled into dunes even in the three-kilo breezes that pass for gales here. I can see it looking like obsidian if it gets melted and frozen again. What I don't see is what on this ninety-K iceball could ever melt it."

"I've suggested methane rain, dissolving rather than melting the surface of a dune as it soaks in and forming a crust as it evaporates," came the much milder, thinner, and rather snappish voice of leukemia VII case Ginger Xalco.

"And I've suggested landing and finding out firsthand whether those nice, smooth, glassy patches and hillocks are thin shells of evaporite over dunes and dirt, as you're implying, or the tops of magma lenses," snapped Goodall. "When do we do that? You've plenty of juice now, Gene. Why not take a good look at this one—whether it turns out to be just another item for Maria's maps or something really different? And don't tell me it's against the advance plans; we're here to find things out, and you know it. To quote the poetic characters who wrote our mission plan, 'There's no telling in advance which piece of a jigsaw puzzle will prove to be the key to the big picture.' "

Goodall, in legal charge of the project, could have given all this as a set of orders, but the many decades' intrusion of military discipline into basic research was not yet that deep.

"It's not a matter of set policy," Belvew replied as mildly as he could—he had his own troubles, even if they didn't include SAS; but Goodall was his commander, in a rather shaky way. "Dodging risk to the jets before the seismic and weather gear are all deployed is common sense, not just policy, and you know it. Once they're in action, long-term studies can go on even if we lose transport for a while. We've made one landing already to deploy a factory, and a couple of others to restock from it, after all."

"I know. Sorry." Goodall didn't sound very sorry, actually, but courtesy also had higher priority than mere discipline. Without it, discipline would quickly evaporate even among adults, as most of surviving humanity had eventually learned the hard way. "It'd be nice to be around when some of the results crystallize, though. And you can't count the later landings because they were in the same place and we knew what to expect."

"Not exactly. The original shelf was gone."

"The area was plain Titanian dirt, mixed tar-dust and ice we guess, with no cliff to fall down this time. Even I could probably have set down safely." No one contradicted this blatant exaggeration. "The old saw about dead heroes—"

"Doesn't apply, Arthur." Maria Collos, somehow, was the only one of the group who could manage to interrupt people without sounding rude. Perhaps it was because her own ailments, a pancreatic cancer and consequent diabetes, were being handled by Status and gave her little pain or inconvenience; she merely knew she was dying. "We're already dead heroes. We've been told so." There might or might not have been sarcasm in her tone. No one else, even Goodall, spoke for a moment. Then Belvew referred back to the landing question.

"I'll be glad to do a ground check after finishing the Four line, if Maria's radar and my own eyes can find me landing and takeoff surface. We can start getting seismic info without Line Five. Actually, we're all as curious as Art about the smooth stuff, and it's good tactics to eliminate possibilities as early as opportunity lets us. Let me top off these tanks just to play safe, and then you can put me back where I left the Four leg, Maria. After that's done we'll scout your new patch for landing risk, if you're not doing that already."

No one commented, much less objected, and Gene made his remaining passes through the thunderhead with no stalls. Oceanus was struck more than once by lightning, but this risk had been foreseen. Strips of conducting polyacetylene—no one had expected to find a convenient source of copper or silver near any of the ice bodies orbiting Saturn—extended from wingtip to wingtip and from nose to tail, preventing any large potential difference in the basic structure. The discovery after the factory had matured of silicate dust containing a reasonable amount of aluminum had been a pleasant surprise, and gave hope for more jets eventually than had been planned.

There were no remarks about Belvew's near stall, either; nearly all had flown the ramjets at one time or another. The exceptions were Goodall, whose own senses were drowned in pain too much of the time to let him use a body waldo safely; Pete Martucci, whose reflexes, though he was one of the very few of the staff not known to be dying of something, had never been good enough to trust during landings; and the, doctor, Lieutenant Colonel Sam Donabed, who had actually never learned how to fly. Even these knew the ordinary problems of piloting and could take over controls if necessary.

"Standard turn left four five point five," Maria said without waiting for Belvew to report that his tanks were full.

"Left four five point five," he acknowledged, banking promptly to seventy-four degrees. The group had agreed on a half-Earth gravity as a "standard" coordinated turn on Titan. The ramjet's wings, stubby as they were, could still give that much lift at ram speed below thirty kilometers or so altitude. He snapped out of the turn in just over sixteen seconds, since mission speed was an equally standard one hundred meters per second when nothing higher was needed.

"Your heading is good. You'll reach the break in Leg Four in two hundred fifteen seconds from—now! Nose down so as to reach three hundred meters at that time. We've allowed for the speed increase at your present power setting, so don't change it. On my time call, level off and do a standard right turn of one seventy-seven point three. Start dropping cans at standard intervals ten seconds after you finish the turn. The leg ends at the twenty-second can." It was still Maria's voice, though Status must have provided the figures.

"Got it." Belvew remembered again, with the aid of the blunt needle mounted in the suit under his chin, not to nod. There were no more words until the time call, and no more after it until the last of the pencil-like "cans"—containers for seismometers, thermometers, ultramagnetomers, and other data collectors—needed for the fourth leg of the planned seismic network had been ejected. There had been only one more of the randomly timed reality breaks which reminded pilots that they were not in fact on board the jets they were driving, and it had failed to interrupt anything important.

"Okay, Maria, take my hand." Gene nosed the jet upward and increased thrust as he spoke. All the others were listening and watching as their particular instruments and duties allowed, except Goodall. He was meticulously testing the output of each of the recently dropped instrument sets. Nothing interrupted the terse directions which followed the pilot's request, and Oceanus swung back toward Lake Carver and hurtled northward along the eastern shore eight hundred meters above its surface, with Gene's earplugs still silent. He knew that others, probably more than usual in view of the proposed landing, were examining lake and shore as minutely as they could on their duplicates of his own Moll-weide, while Maria was using her station-based instruments, each employing its own combination of active and passive radiation. He could expect to have his attention called to anything he seemed to be missing, so he concentrated on the screen area a third of the way from center to lower margin, which displayed the region he would pass over in the next few seconds. This section was only slightly distorted by the projection that let a single screen squeeze the full sphere into an ordinary human field of vision. This mattered little, actually; everyone had learned long ago to correct in their own minds even for the extreme shape error at the edges. No part of the aircraft itself showed; many of the two dozen cameras mounted in various parts of its skin did have bits of wing, body, or tail in their fields, but Status in blending their images on the single full-sphere display routinely deleted these.

Unfortunately.

The surface of the lake was currently glass-smooth ahead and left of the jet, though even Titanian winds could often raise waves; gravity was weak and liquid density and viscosity low. The highest winds seemed to occur over liquid where evaporation lowered the air density far more than likely temperature changes could. Belvew gave the lake only an occasional glance, keeping his main attention on the land ahead where the feature to be examined should be.

"Three minutes," came Maria's quiet voice. The others remained silent. "Two. You may be able to see it now." The pilot scanned through his vision frequencies again, dodging the wavelengths which were most strongly absorbed by methane.

"I can, I think. Forget timing. I'm slowing to ten meters above rain stall—no, make that twenty for the first run—and going down to a hundred meters. And cut out the reality reminder, Status. If I ever lose track of where I really am we can cut my shift short later. I'll recover. The air looks steady, but I don't want another stall at this height."

No one objected aloud, though there must have been mental reservations. Belvew was the pilot for now; it was up to him to weigh relative risks to the aircraft. Negative comments would have been distracting, and therefore dangerous as well as discourteous.

The smooth patch grew clearer as the seconds passed. It was much larger than most of the many seen so far, about half a kilometer across, roughly circular in shape but with four or five extensions reaching out another hundred or hundred and fifty meters at irregular points around its circumference. It might have been an oversized amoeba as far as outline went. The color seemed to be basically black, though it reflected the pale reddish orange-tan of the Titanian high smog as though from glass.

No small details could be made out from the present altitude and speed. Gene banked, to much less than standard turn rate at this speed, swung in a wide, slow half circle north of the patch, and made a second pass in the opposite direction. This time the reflection of the brighter section of southern sky where the Sun was hiding could be made out; the surface looked more than ever like glass, as Maria had said for the others she had mapped, but there were still no informative details.

He made two more runs, this time at thirty meters above the highest point of the patch and only two meters per second above ram stall, tensely ready to shift to rocket mode—to cap the air intakes and feed liquid and extra heat into the pipes at the slightest drop in thrust. He was not worried about the wings stalling; even those stubby structures had plenty of lift area in this atmosphere and gravity, and the jet had been designed so that they would go out at higher airspeed than any control surface.

Nevertheless, his attention was enough on his aircraft and far enough from the ground so that it was Barn who spotted the irregularity.

Copyright © 1999 by Hal Clement

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