Half Life (4 page)

When it seemed certain that no replacement factory would have to be sent out, the fact that only a short length of ice shelf remained for takeoff had had to be faced. Inger had used maximum thrust, in rocket mode of course, and maximum-lift wing camber. While he concentrated his attention straight ahead, the rest of the group watched another crack chase him along the shelf, and more ice rubble fall, bounce, and roll toward the new factory. There was no longer any ice platform to land on when he did get airborne and reached ram speed.

The two later descents to pick up cans, once the factory had matured and started production, had been on “ordinary” ground and proved uneventful. The drag on the skids, which all had feared might stress the aircraft too highly—this was why the ice shelf had been chosen for the first touchdown, though the ice was merely smooth rather than slippery on Titan—had been strong but not dangerous, and the subsequent takeoffs had presented no problems except a rather larger demand for reaction mass than had been hoped.

Belvew remembered the ice landing vividly as he planned his present one. Some dangers were now more foreseeable, but concentrating on these might lessen his readiness to respond to the unforeseen as promptly as his friend had done. He could, it occurred to him, land on the ordinary-looking ground beside the smooth patch; the labs were mobile and could eventually get the information he was after.

Except the strength of the stuff. That would have to be known sooner or later, and sooner seemed better.

His determination to land
on
the patch crystallized firmly.

Well,
Theia
and
Crius
were still available at the orbiting station, or should be in a few days, and the chance had to be taken sometime. No one would would blame him for losing
Oceanus
.

At least not out loud. The aircraft was statistically almost certain to be lost sometime, and
someone
would presumably be flying it. But please, General, someone
else
.

He called for a wind check—even a meter or two a second could make a difference—and held a constant heading for ten kilometers while Inger adjusted a superimposed grid on his own screen’s image.

Eventually the moving ground features followed one of the lines and let him time their apparent motion.

“Only zero point seven, from eighty-seven,” was the verdict. Belvew swept out over the lake without asking Maria for a heading, lined up with the patch from a dozen kilometers to the west, and eased back on his power.

For just a moment. Then, reflexively and almost suicidally quickly, he shifted to rocket mode and nosed steeply upward, with a dozen or so alarmed voices in his ears.

It was not a reality pause which suddenly blocked his view of Titan, but reality itself. He should have seen the slight dimness drifting down the center of his screen against the almost-as-dim sky, but he had allowed his attention to center too deeply on the proposed landing site. Most of his colleagues, even Inger, who should never have allowed any such thing to happen, had done the same.

Rain does not pour, or even fall, on Titan; it drifts, not always down. The gaseous nitrogen is dense, liquid methane is not, and gravity is weak. Terminal velocity for a raindrop is very low, so drops do not get torn into small fragments as they do on Earth; and they don’t even start to descend at all rapidly until they are marble- or even eyeball-sized.

A camera lens which encounters such a drop doesn’t break but does cease briefly to form an image, and the portion of Belvew’s Mollweide covering the space ahead of
Oceanus
went effectively blank though not dark.

He could still see aft, but that was not the way he was traveling. He climbed sharply, watching airspeed carefully. At least there was no other traffic to worry about.

He was out of the rain in a minute or a little more, and flying visually again as the lenses dried. The Titanian landscape ahead was less fascinating than the well-developed thunderhead behind, which everyone was now examining with great interest.

No one said a word of blame. All who had been using the Mollweide image had missed the rain. They had all, including Inger, been watching the intended landing site too closely.

Belvew drove deliberately back into the rain to restock his tanks—he had not used much mass, but had completely lost the urge to save time at the expense of low reserves—and circled while the cloud and its precipitate drifted slowly out of his landing approach path. He felt a slight temptation to pass up the landing and go back to sowing cans, but knew he would lose the resulting debate. Goodall would not be the only one against him. A pilot’s authority was not absolute unless he or she was actually aboard the aircraft.

Fifteen minutes later,
Oceanus
was just where she had been when she had flown into the rain, and Gene was once more in the middle of landing procedure, easing back on thrust. His attention again was straight ahead.

Most others’, especially Inger’s, was more diffused.

He nosed up enough to split the result of decreased thrust between descent rate and speed loss, and reached the shore fifty meters above the liquid and a scant two meters a second above ram stall.

Chewing his lower lip, which fortunately affected no waldo controls, he closed the ram intakes and fed liquid to the plasma arcs. There was a grunt of admiration which might have come from Goodall; the shift to rocket mode was almost perfectly smooth. The longitudinal accelerometer shifted slowly from zero to a negative reading, and stayed there as Belvew nosed down and turned his fires even lower. He was approaching wing stall now, and began increasing the camber of his lifting surfaces toward the barrel-section shape which had been used so few times before, and never by him. He suddenly realized he should have done a few practice stalls two or three kilometers higher. He convinced himself quickly that breaking off the approach and going up to do this now was not necessary, but he didn’t ask for anyone else’s opinion.

The rippled surface of the satellite was forty meters down. Thirty-five. Thirty The glassy convexity loomed ahead, rising to meet his keels. He nosed up even more, very gently, killing descent briefly while airspeed continued to drop. The bulge kept rising toward him. Without orders, Inger began calling airspeed aloud. The wings
should
maintain lift down to sixteen meters per second at his present weight, Belvew knew, and the stall then
should
be smooth. Some levels of theory were solidly established.

“Twenty-two zero—twenty-one nine—twenty-one eight—”

The keels were two meters from the bulge, and he nosed up still farther to keep them so as the airspeed continued to fall. That wouldn’t work much farther; past the top of the dome he’d have to drop the nose to make contact before stall, and that would speed him up unless he eased back on thrust with a precision which only practice could have given. Not very much speedup could be produced by Titan’s gravity, but any at all would complicate the landing.

The side edges of his screen darkened suddenly, but he kept his attention ahead. If there was anything important aft, someone would tell him this time, though he hoped they wouldn’t before he was stopped.

For an instant he wished he were actually riding the jet, so that he could
feel
when touchdown occurred.

But he knew anyway. The accelerometer and three human voices told him simultaneously. He stopped mass flow and quenched the plasma fires almost completely, but kept ready to use fractional rocket power on one side or the other if a swerve developed. A severe yaw too close to touchdown speed could roll the
Oceanus
onto her back even with the keels three meters apart, and it seemed most unlikely that whichever wing was underneath could take such treatment.

“You’re down!” came Ginger’s rather snappish voice, this time separate from the others’. Belvew snorted faintly, and spared enough of his attention to utter a bit of doggerel which had survived in various forms from the time of fabric-covered aircraft.

“A basic rule of flying, and one you’ll always need: An aircraft’s never landed until it’s lost its speed.”

But deceleration was now rapid as the keel friction made itself felt, and a few seconds later the landing was complete. Belvew knew he wouldn’t feel it, but his stomach tightened up anyway for several more seconds as he watched screen and vertical-motion meters for evidence that the ship was breaking through a surface.

Apparently it wasn’t, and at last he felt free to let his attention focus on the view aft.

The screen darkening was from a slowly spreading cloud of black smoke, its nearest edge well over two hundred meters astern. It could not, the pilot judged at once, have been produced by friction between his keels and the surface; his landing slide hadn’t started that far back, and skin thermometers showed that the keels were at about a hundred and fifty kelvins. This was considerably but not worrisomely above ambient. They were cooling rapidly, but not so quickly as to suggest they had been hot enough in the last few seconds to boil Titanian tar.

Not that anyone really knew what temperature
that
would take, Gene reflected fleetingly.

More to the point, a fairly deep trough in the surface, starting just below the near side of the smoke cloud and extending as far back along his approach path as he could see, confirmed that whatever had happened to the surface had come before touchdown. The most obvious cause was hot exhaust. He was too busy at the moment to devise the GO6-demanded alternative hypothesis, so he refrained from uttering this one aloud.

The smoke was being borne very slowly away from him by the negligible wind. The trough, half a meter deep and ten or twelve wide, remained uniform as the receding cloud revealed more and more of it, extending down the slope of the convexity. The jet had come to rest almost exactly at the top of the bulge, it seemed; both pitch and roll indicators read within a degree or so of horizontal. Luck occasionally assisted virtue, Belvew reflected.

“If it’s a crust, it’s pretty solid,” Goodall remarked.

“Unless the jets melted their way down and just produced more of it,” rejoined Ginger.

“Could be, but they didn’t touch the spot where we are now,” the commander pointed out. Like the rest, he knew that at least one alternative hypothesis, however unlikely or unappetizing, should always be proposed as soon as possible after a first public speculation; Ginger had behaved properly. Still, it was so much better if the alternative was reasonable…

It had also been quite proper for the commander to point out possible flaws. Objectivity was, after all, important. “Let’s get samples.”

Belvew had powered down the flight controls, except for those which might be needed for emergency takeoff, and could safely nod his head, not that the others could see him from their own quarantine compartments.

“All right, in a few minutes. Nondestructive examination first. I assume everything in sight’s been recorded; now let’s
look
.”

“Right.” Goodall’s voice was a fraction of a syllable ahead of the others’. Belvew activated the short-focus viewers on the lower part of
Oceanus’s
fuselage and allowed their images to take over the Mollweide screen as his friends above chose—no, not above, he reminded himself;
he
was
above
with them; another real-surroundings reminder must be about due. No one, however, said anything for several minutes; the surface still resembled obsidian or tar at every magnification available and at every point the viewers could reach. The depression seen from the air was now hidden by the curve of the hill ahead, even though they were looking from the top of the bulge, and the nearest point of the track left by the landing approach was too distant for a really good look.

“I guess we dig,” Pete said at last. Belvew nodded again, as uselessly as before, but operated more of his controls.

The object which dropped from between the keels might almost have been an egg-shaped piece of the surface itself, as far as texture went, though its color was much lighter. It measured about fifty centimeters in its longest dimension. Until it reached the ground, which took an annoyingly long two seconds in Titan’s gravity, it appeared totally featureless. When it did strike, it flattened on the bottom to keep from rolling, uncovered a variety of optical sensors on the top and sides, and deployed handling, liquid-sampling, and digging apparatuses, coring tools, and locomotion equipment.

Structurally and functionally, it straddled the accepted arbitrary borderline between nanotech equipment and pseudolife; it had been grown like the cans and the jets, not manufactured, and much of its internal machinery was on a molecular scale. It was about as capable of self-repair as a healthy human being, both ranking far below a starfish.

“Take it, Art. Where to?”

“Aft, I’d say. I’ll sample at each meter until we reach the exhaust trail, if that’s what it is, and then really dig. The smellers report ready.”

The “smellers” were of course the analytical equipment, and everyone began to tense up again as the egg crawled to its first sampling point and its iridium-coated scraper went to work.

“How hard?” queried several voices at once.

“Only about three. If it’s a crust, it must be pretty thick to take
Oceanus’s
weight.”

“Composition?” This answer was slower in coming, naturally, but overall percentages were ready in less than a minute.

“Carbon fifteen point seven one; nitrogen eighteen point eight eight; hydrogen four point one one two; oxygen twenty-eight point two five; phosphorus—”

“Phosphorus?” Again several voices merged. The first three elements had all been observed in samples of the atmospheric smog, and there was nothing surprising about the oxygen in view of all the water ice; but this was the first third-period element other than aluminum and silicon to be identified on Titan.

Study of presumably prebiotic substances had the main mission priority, of course. Whatever was decimating humanity was probably biological and therefore chemical in nature; new diseases, new varieties of older diseases, even newer combinations of both were appearing and spreading faster than causes could be identified and treatments devised. It had seemed at least possible that Titan might be in a prebiotic stage, and might provide origin-of-life data which could fill the still broad gaps in existing theory—broad in spite of the advanced development of pseudolife equipment. Of course even such data might not be meaningful for terrestrial biology, but with energy and construction expenses almost zero, this expedition or almost anything else seemed worth trying. Human beings were desperate and individually expendable; one might as well die
usefully
.