Half Life (3 page)

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, ultramagnetometers, 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 Mollweide, 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 ram 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.

“The thing humps up pretty far at the middle; it’s more of a hill than a patch of something,” the copilot reported. “There’s a hollow about ten meters across halfway from the high point to the base of that northeast arm. It did funny things to our reflection as we passed this time, but I can’t see it now. The whole surface is reflecting sky, and that’s pretty uniform. I couldn’t decide exactly how deep the hole is, but it’s just a dent, not a real crater.”

“Did anyone else spot it?” asked Belvew. Most of them had, but none could give any better description.

Even Maria had not been Dopplering the site. He made another low pass, this time devoting a rather dangerous amount of his own attention to the surface below. He saw hill and hole for himself, but could make out no more details than any of the others.

“You know we’re going to have to land sometime,” Goodall remarked in what was meant to be a thoughtful tone.

“I know.” Belvew was thinking, too. There was half a minute’s pause before the commander, who would be operating the remote-controlled labs and wanted to get at it, tried again.

“What time is better than now?”

Gene could answer that one.

“When we know more about the strength of that surface. If it’s just a crust, as the rain hypothesis suggests,
Oceanus
could break through and smother the jet scoops in dust, or mud, or dirt, or whatever form the stuff under it happens to have.”

“But we’d land in rocket mode. The scoops would have to be closed.”

“And if the tailpipes were covered too? We haven’t even risked a lake landing yet.”

This was quite true, but Goodall was not yet out of ammunition, and riposted instantly. “You have plenty of cans. See what happens when one of them hits. Hold the chute; let it hit as hard as Titan can make it.”

“Good idea.” The pilot, with much relief, cautiously raised his speed to standard—too sudden a boost to the heaters could make a pipe front-fire—and climbed to a full kilometer. There was still no real wind, but the patch was a harder target than he had expected. Without its parachute the slender container took much longer to lose the jet’s speed, as all had expected but none could estimate quantitatively. Status’s attention had not been called to the problem.

The first drop overshot badly. Belvew couldn’t see it, or rather didn’t dare watch it closely, but Inger and Collos followed it with other instruments until it buried itself beyond detection in ordinary, firm Titanian “dirt” a hundred and fifty meters beyond the edge of the glassy patch.

The second try, with Barn calling the release moment, went much better, and was quite informative in its way. The can’s own instruments stopped radiating at the instant of impact, ending passive measurements, but Maria’s shortest viewing waves showed that the little machine, solid as it was, had shattered on contact without penetrating. The surface seemed pretty solid.

Belvew was less happy than he might have been. If the can had broken through undamaged it would have implied a crust probably too weak to take the jet’s weight, much less the impact of a poor landing. That would have provided a good excuse for not putting down just here and now, and spared him an increasingly worrisome decision.

As it was, the next move appeared to be up to him. Even had the time for shift change been closer than it was, he was mature enough to be embarrassed at the thought of passing a responsibility to anyone else. He thought furiously. Would anything
except
an actual landing tell them what they needed to know?

The jet lacked landing gear in any ordinary sense; there were no wheels, floats, or real skids. Its belly was a pair of solid flat-bottomed keels meant to give stability during a liquid landing and broad support on dubiously solid surfaces, though once stopped the fuselage would sink to something like half its vertical diameter and part of its inner wingspan in the best-guess mixture of Titan’s lakes. It would float a little deeper in pure methane. This was why no one wanted to make the first lake landing; it had not occurred to the designers of
Oceanus
and her sisters until much too late to calculate, much less test, the results of attempting a rocket-mode start with the pipes, whose pods were below the wings, totally immersed in liquid. The log of the Earth-to-Saturn orbit had several annoyed entries about such oversights in equipment design. The outbound trip had consequently been much less boring than anyone had expected, and decidedly busier. Many staff members had spent much less time in deep-sleep than had been planned, and so there had been more disease fatalities than expected. This had helped settle the trivial argument about whether the half-life of the crew should be measured from Earth departure or Saturn arrival—trivial because everyone knew as well as the planners back on Earth that the number of units was too small to justify that sort of statistic.

Fortunately, the budget for contingency personnel in the original planning had been based on pessimism.

So far the keels had seemed to be adequate landing skids on a reasonably solid surface. Belvew thought carefully. One
could make
a pass at just above wing-stalling speed, grazing the apparently smooth hump.

If he did it right, he might really resolve the question of whether the patch was solid or crust—if it broke under him. If it did not, of course, there would be no certainty about its ultimate strength until a real landing was made, the jet had come to a stop, and the wings lost
all
their lift. Might as well do that the first time.

The convexity of the patch complicated the problem slightly. If he landed too hard—easy to do on the upslope side and, now that he thought of it, even easier on the other—the question of whether the crust was stronger than the jet’s belly and keels would also become relevant. Here too there was a designed but so far untested safety factor. A whole, especially an extrapolated whole, is never equal to the sum of its parts—Euclid had not been an engineer, or at least had apparently never considered synergy.

The initial landing, a Titan day before, had been on a smooth shelf of ice near the foot of the upthrust side of what looked like a tilted block mountain; Titan seemed to be still active tectonically. There had been no trouble anticipated in detail, though of course the pilot—Inger, that time—had kept alert for the unforeseen. This was fortunate, since the rocket exhausts had started a thermal-shock crack in the ice which chased the jet for most of its landing slide. The pilot had just managed to avoid riding to the foot of the hill on several million tons of detached shelf by a final, quick shot of thrust. The three hours it had taken Goodall to steer the factory seed pod through its climb to the bottom, walk it to a safe distance from the cliff face and the new pile of ice rubble, put down its roots, and start it growing had been spent in a high state of tension—mostly by Inger, who was in no more physical danger than anyone else, but who
was
the current pilot. If he hadn’t been able to get
Oceanus
off again, little but remote mapping could be done until Carla lePing and her colleagues had the next aircraft ready.