Half Life (25 page)

“And maybe the lighter layers in the strata!” interjected Carla lePing, beating her coworker to the suggestion. “At least they’re the right color!” Status made no comment.

“I’ll look anyway. Heading, please?” Ginger relaxed; at least this should be a more comfortable ride. It was, though no one would have been paralyzed by shock if it hadn’t been.

There was still no snow, and relatively little surface ice showed in the dirt; Lake Carver was on Titan’s darker trailing hemisphere. Ginger was not, as she had tacitly admitted, eager to land, but she had no intention of handing Belvew the responsibility. She made all reasonable delays, looking unsuccessfully for nearby snow patches, doing a careful wind run, and even topping off her mass tanks at a nearby thunderhead—she had used rocket mode once or twice in the turbulence—but it seemed clear that dropping a lab even at minimum speed and altitude was likely to wreck the equipment. Even if the device were still able to heal itself afterward, that would take much longer than a landing.

The pilot still hoped that Maria would decide to risk a drop in spite of all this, but the commander concluded that the balance favored touching down. Ginger sought and found Belvew’s Pool with Carver in the background, lined up
Theia
toward it, and began her approach. She had found no wind and observed neither rain nor turbulence along her flight path, so there was plenty of time to adjust letdown rate. She wanted to touch just at the bottom of the near side of the gentle slope—she wondered suddenly why neither of the other named pools had shown either such a large bulge or a dimple like the one originally spotted here by Inger, but put the question firmly aside. This was no time for theoretical work. She was a little above pipe-stall speed—closer than Belvew had gone before shifting to rocket, she recalled; but he’d been enjoying a small head wind. Not that that made any difference with airspeed. Fifty meters above ground, six hundred from touchdown She closed the intakes and began to draw from
Theia’s
mass tanks. She could feel her bare scalp—her nickname dated from her teens, years before she had qualified for Titan, and even before her infection—trickling with perspiration, and she was fleetingly glad of her isolation. Belvew, his screen and other instruments copying hers, hoped his relief at the near-perfect mode shift was inaudible. Someone else gave a grunt which might have been approval; the change to rocket mode had barely shown on the accelerometers.

Thirty meters up and three hundred to go. Now she had to watch for imminent wing stall. She was overshooting a little. Nose and power both down just a trifle, but watch that airspeed. The bulge of the pool now hid the lake. She should still touch down on this side, but might not stop sliding before the top.

Still overshooting—was a tailwind picking up? If another updraft was starting to grow over the lake, that would be its effect.

She couldn’t touch now less than halfway up the near slope. The air
must
be moving. No matter. She could still—but yes, it
did
matter; beyond the top the slope was downward, and that was when even Belvew—cancel that “even,” blast you, Xalco—had expected trouble. Not much, but some.

Her keels touched before
Theia
reached the top, but not very much before. There was a swelling black cloud at either side of her screen just as Gene had had, and she cut thrust the instant her accelerometers showed the ground drag.

Not soon enough. The jet ballooned, probably only a few millimeters, but failed to touch again until it was halfway down the lakeward side. She had had to nose down, of course, which raised airspeed slightly. It wasn’t much of a slope and the aircraft didn’t have much wing area, but Titan doesn’t have much gravity.

Then she was firmly down and slowing rapidly.

Not as rapidly as the now very visible lake was approaching, however. There
was
a thunderhead growing over it, she noted in surprisingly detached fashion as the jet crossed the shoreline and the splash blanked her Mollweide for a few seconds. That should explain the unexpected tailwind, she thought; but she didn’t voice the speculation. There were more important things to consider.

“Well, we had to find out sometime.” At least the remark hadn’t come from Belvew, and there was no way for anyone to tell how frantically the commander had striven to beat the sergeant to it. “What’s the lake density, Status? You have
Theia’s
mass and volume parameters and can read how deep she’s floating.” Maria seemed completely calm.

“A little higher than expected for a ninety-ten methane-ethane mixture at that temperature, but not outside reasonable variations in such a mixture. If the major will eject a laboratory we can—”

“Not till you’re ashore!” Belvew did get that exclamation in first. “We know the lab won’t float, and we can’t hear its output from under the surface.”

“Strictly speaking, we don’t know it won’t float,” the commander pointed out. “The density of lab and lake certainly aren’t very different. We never really looked for the other on the surface, and it might have been damaged enough by the exhaust that blew it away so it failed to broadcast. However, I agree it would be best to get ashore first. I’d suggest very, very gentle thrust in rocket mode, Ginger.”

“And expect it to be pretty bumpy even then,” pointed out Belvew. “The liquid will boil around the arcs and the bubbles will drive huge masses of liquid out the pipes. That’ll stop as the arc clears itself, and repeat when juice sloshes into the fire again. It’ll be like pouring from a narrow-necked bottle, I’ll bet, and the sloshes may not stay in step between the engines.”

The “I’ll bet” was encouraging. Not even Belvew, it seemed, was certain what would happen with the pipes submerged and flooded. The point, as someone had realized early on the Earth-Saturn orbit, was another factor overlooked during planning of the aircraft, but no one had seen any way of rectifying the design without risking further complications. The ramjet is simple in principle, but the simplicity does not extend to machines using it. Not one of the original fifty crew members had had confidence in his or her skill in aerodynamic engineering. Getting the needed information from Status would certainly take a worrisome amount of time, and with terrible luck no one would ever ask the right questions.

Xalco wasn’t sure whether Gene’s uncertainty was a relief or
an
added worry. She lit the arcs with even more caution than she had used in the landing.

The jerking wasn’t
bad—Theia
was massive and the lake offered its share of inertia—but the sergeant had been essentially right. Also, the process was
loud
.

As she bumped away from the shore, Ginger experimented with cambering the vertical stabilizer in ordinary steering fashion and found it ineffective. The obvious alternative was to lower the fire in one engine until
Theia’s
nose pointed back toward shore and hill. This worked, complicated by the predicted lack of synchronization in the jolts. Then, even more slowly and carefully, the major began to retrace her path.

“Hadn’t you better tank up?” asked Martucci. “You used juice to land, and will use more getting ashore.”

Ginger didn’t answer directly, but followed the sensible suggestion.

“Status, check how much mass I take aboard, how far it sinks me, and cross-check the lake’s density,” she said. It took her a moment to remember the appropriate controls; all previous refills had been made in flight from air scoops, and opening an inappropriate valve just now seemed unlikely to be habit-forming. Again she fought off the temptation to abdicate responsibility and let Belvew take over.

The mass percentage change was small and the rise in fluid line perceptible only to instruments. Status reported a small difference in the newly computed lake density and claimed it exceeded reasonable measurement error, but the collective human judgment dismissed the difference as unimportant. It was certainly minute.
Theia
resumed the bumpy drive shoreward.

She was close in when the keels touched; the slope of the lake bottom appeared steeper than that of Belvew’s Pool, now called by some Belvew’s Hill. Without consulting anyone, Xalco gently eased more energy into the arcs.

Theia
bumped further inshore as though being tapped from behind by a giant putter on a very wet green, and her bow began slowly to rise. Then forward motion and hammering stopped for fully a second.

Before the pilot could decide what to do, even before Belvew could offer advice, there was an even louder thud and a stronger forward jerk. Both repeated themselves in a fraction of a second, but less violently. Motion and sound ceased again; then Belvew gave a cry of warning.

It was unneeded; the pilot had also felt the arc warning which the sergeant had seen on a different instrument and reacted properly, feeding liquid to both chambers. Another blast from the pipes, much more violent in terms of acceleration but much less noisy than the others, sent the jet completely ashore.

“When the arc section got above the liquid—,” Belvew began.

“I can see what happened,” snapped Ginger. “The pipes are drained now, I expect. I’m dropping a lab right here, Seichi; you can try getting a lake sample without having it lost in the drink. I’ll hold off on thrust until you can walk it to one side far enough. Then I’ll push a little closer to the pool, or hill, or tar pot, or whatever we’re going to call it and drop another—or do you want even more?”

“Two should be enough, but if you can spare more a backup would be nice.”

“All right. Just a moment.” The rockets thundered briefly as
Theia
bumped a little farther from the lake.

“Here go two labs. Get them off to the sides, or to one side, or whatever is handiest as fast as you can, please.”

“I have control of them both. They seem to be responding normally. I have them moving aft… now they’re clear of the keels. Another couple of minutes.” Even Belvew was silent during the wait. “All right. They’re both about fifty meters to your left, almost at the shoreline, and should be clear of your wash. You’re getting closer to the stuff?”

“Yes.” Again everyone heard rocket thunder, and watched instruments and screens as
Theia
slid closer to the rise. “All right, here go two more for you to use on the tar or whatever it is. Move them aft and a little to the right—my left, that is. I’m going to use the right engine to turn parallel to the foot of the slope before I try takeoff; that should use less mass than trying to accelerate up the slope, especially if it’s going to pull the sticky trick. The first two are enough closer to the lake so I won’t be risking them. Nothing else needed on the ground?”

No one answered, and the aircraft swiveled clumsily to its left until it was parallel to the shore a few dozen meters away. Then it accelerated northward, a dark cloud again appearing behind as hot gas swept the lowest fringe of the hill/pool. Ginger had not recited the checklist aloud, but she had followed it. The wings were cambered for maximum lift, and
Theia
was airborne in less than three hundred meters.

The moment it was safe—perhaps a fraction of a second before Belvew would have done it—the pilot shifted to ramjet mode, smoothly enough so that the sergeant nodded approvingly if pointlessly in the solitude of his quarters far above.

Without a word Ginger headed for the now well-developed cumulus cloud above the lake, climbed to four kilometers, and drove into it to refill. She didn’t expect any remarks from Belvew, and there seemed no point in asking for them.

She got one anyway.

“Look at your chamber temperatures and exhaust speeds, Major. There’s something there that shouldn’t be in both pipes, clogging them maybe two percent. It’s lucky you didn’t open the intakes any sooner; you’d have been pretty low for a pipe stall and a lot worse for a front fire.”

“Right.” Ginger was thoughtful. She wasted no worry on what hadn’t occurred; pessimism is a tendency to brood over what might be, not what might have been. The fact that she wasn’t actually riding the jet was irrelevant; losing the craft would have been emotionally worse, she felt, than losing herself with it.

She strongly doubted any afterlife, and even more strongly doubted the chance of being able to correct mistakes once there. Her usual irritation with Belvew suddenly sank, though not too deeply, in a ripple of sympathy.

But there was a piloting problem to be faced, and she gave it all the attention she could spare from steering the jet through the nearby cloud and operating the collection equipment. She even asked for help.

“Status, watch those engine readings and let us know if you detect any change in any direction. You needn’t recite the readings themselves, but let me know whether the obstruction they indicate is increasing or decreasing.”

“It is decreasing,” was the instant response.

“Something sticky got into the pipes while they were submerged and is burning out now,” Belvew concluded promptly.

“Or into the tanks,” Mastro and Wei snapped out almost simultaneously. Belvew kept his annoyance to himself; he should have thought of that before opening, or at least before closing, his mouth.

“Let’s hope it’s just the obstruction that burns,” Ginger said, acknowledging obliquely the higher probability of the first idea—the other would obviously have called for increasing pipe blockage—by failing to comment on the alternative.

“A reasonable
speculation
,” the commander put in, out of a sense of duty. Belvew did tend to become positive in his ideas rather earlier than regs or rationality advised. “Seichi,” she went on before the sergeant could react defensively, “have you any analysis of the lake yet? Is there anything which might explain this?”

“The lake is mostly methane, ethane, and small amounts of higher but still simple hydrocarbons,” the analyst replied promptly. “The key word, though, does seem to be
mostly
. Maybe half a percent of the stuff is extremely complicated, and it’ll be a long time before I can get even a rough composition. It’s certainly a mixture, not one or two nice, clean compounds with readable structures and writable formulas.”