by Hal Clement
An hour later and a third of the way around Titan he felt the touch of drag. Orbital velocity, less than two kilometers a second, was too low to cause a serious heating problem, and before making a full half circle from the point where he had left the mass of ice—which was still in view—he was using wings and aerodynamic controls, and had uncapped the pipes into ramjet mode.
The rest of the flight was uneventful; it was a new adventure for the aircraft, but not for Barn. Finding an adequate cloud and using it to fill the tanks with hydrocarbon, had been a long routine. Clearing the tanks first of the traces of unused water was not, but he knew very well what ice crystals at liquid methane temperature could do to Crius’ pumps and needed no reminding from his fellows. He took care of the matter early enough so that Belvew, letting his attention wander slightly from the jet he himself was operating a quarter of the way around the satellite, felt no temptation for over-the-shoulder driving.
Finding the factory and landing beside it were also routine; Inger had been the first to take one of the ramjets to the surface. The fact that he had not been physically aboard then was incidental; the Waldo suits worked either in direct-connection or remote modes, the latter suffering only the signal-travel delay which the distances involved made negligible.
Crius slid to a stop a couple of hundred meters from the factory. Its pilot completed the power-down check of the aircraft and the Titan environment check of his suit, and emerged. There was no need to report the fact even to his partner; everyone had presumably been watching carefully.
Even Belvew was having a problem of his own.
Theia was high enough in the smog layer for Saturn and its nearly edge-on rings to show dimly on her screen, though they were rising and setting too fast for comfort. Gene ignored the sight as best he could. Circling Titan’s south pole at one hundred meters per second and increasing the radius of the circle by half a kilometer each time around took no attention, of course; that sort of thing could be set up in advance. The satellite’s rotation axis being a couple of degrees from perpendicular to its orbit plane was merely background information, though it was responsible for Saturn’s present peek-a-boo behavior. The bothersome item which did demand attention was a steady altitude loss by his aircraft.
It was not frightening. The ground was fifty kilometers down and the descent mere centimeters per minute, but it was puzzling. It was also annoying; correcting the altitude manually every minute or so was a nuisance, while setting the automatic pilot to do it might hide important data in unrecorded corrections. There was also the matter of self-respect; the sergeant wanted to explain the phenomenon himself before Status, whom he preferred to think of as Nursemaid, made him feel foolish again. His rank might imply a mere observer rather than theorist, but he considered himself perfectly qualified to think.
Thrust and attack were correct, and corresponded to the airspeed. Energy consumption matched the mass of the atmosphere being cycled, the push indicated by the ramjet mounted sensors, and the weight of the aircraft. There were no lake thermals at this height at latitude. There must be some obvious factor he hadn’t—
There was. The calm voice of Status, committed to reporting changes of background whenever they reached a certain probability without regard to their dangers, made itself heard.
“There is a slow general descent of the polar air mass covered so far on this run. Symmetry suggests it to be quite precisely centered on the pole itself. There must be poleward flow above Theia’s present altitude, and equatorward below. Repetition of the present flight pattern at a larger number of levels than originally planned appears in order. When the entire volume has been vector-sampled I suggest comparison with the total upward flow over the lakes.”
Belvew could think of only one response which might restore his morale.
“How does air density match norm for this height? It should be greater if there’s such a huge downdraft.”
“It is. Qualitatively this could explain the effect.”
“And quantitatively?”
“Unanswerable until vector analysis is more nearly complete.”
Another thought restored Belvew’s self-esteem even further, and he voiced it before the analyzer bait him again.
“Is there enough more smog in the air to account for the higher density?”
A human voice cut in. Even now it sounded slightly amused, though no one knew why.
“Wouldn’t more polymer drop the density? It’s made from the surrounding gasses, and would use them up as it’s produced.”
“It would drop volume, Maria. The mass would still be there and contributing to pressure, I’d say; and that would start inflow which would carry solid and liquid particles from a distance—” The debate was interrupted.
“The inflow wouldn’t be in. It would be around. There’s Coriolis force even with a sixteen-day rotation and small planet size, and no surface friction fifty kilos up.” The new voice was Arthur Goodell’s, and no one added anything for a moment; the old fellow had an annoying habit of being right, as well as being officially their ranking member. Belvew was about to take a chance on mentioning the minuteness of the Coriolis effect, but was saved by Status’ voice.
Goodell himself, in his sealed quarters a hundred meters from Belvew’s, paid no attention to what the computer said. He had known as the words left his mouth that his reasoning was sloppy. It was getting constantly harder for him to think coherently, and more and more of his time went to wondering how long he could be useful at all to the project. The pain kept getting worse. He had been told long ago that the discomfort of SAS—synapse amplification syndrome—was less severe than that of shingles, but he had never asked how his informant knew. If anyone had ever suffered from both it must have been at different times for the effects to be distinguishable, and whichever had been experienced later would have been remembered as being worse. Arthur Goodell had the scientists’ natural mistrust of data dependent solely on human memory. Besides, he knew of no technique for actually measuring pain.
He knew all he wanted to know about SAS. Unlike shingles, it affected every square centimeter of his skin at one time or another, but caused no external markings. Like shingles and chicken pox, it was produced by a virus, one which had been identified and mapped within weeks of the first recognition of the disease. It differed from the shingles agent in only four amino acids at specific points plus one bundle, perhaps originally a separate organism, which rendered it unresponsive to both natural and engineered human immune systems. The four amino acids were few enough to be explained by natural mutation, but numerous enough to make human tampering a reasonable suspicion; the bundle was natural, but might have joined the virus either with or without human assistance. It made no difference to Goodell whether he should be blaming Nature’s indifference or human malice; the molecular engineers who now made up most of the medical profession had not yet worked out either a nonlethal contravirus or a simple chemical treatment.
They had, of course, a lot of work to do on other ailments, and there were only a few hundred cases of SAS to worry about, so there was no use complaining about being at the short end of a triage situation. That was an everyday state of affairs for humanity in general.
With the pain growing ever worse, what he really wanted now was not a cure—not exactly. He wanted an opportunity. This should, he felt, be found some time on Titan: one of Maria Collos’ gel pools, not too far from a lake, and isolated in some way from the rest of the moon’s surface would be ideal.
There were a few traces of impact craters on the ever growing map Goodell himself was developing. Their walls might provide isolation, though all seemed to be badly weathered or nearly buried. There seemed to be no high winds in Titan’s heavy atmosphere, and methane rain should be a far weaker erosive agent than water, but both had had several billion years to do their work.
At least two of the craters on Maria Collos’ less specialized maps did contain small lakes. This was hopeful, and the maps still being r
evised and extended, partly in the standard course of planned operations but often by Goodell himself. He wondered more and more frequently how long he could keep that up; solid, detailed work did still keep his attention from pain, sometimes for hours at a time, but the distraction of his body was getting harder and harder to fight.
The chances of finding an ideal site for his slowly developing personal project were actually decreasing, though he was not admitting this yet to himself. The equatorial regions had now been pretty well mapped, and his personal travel problems made the rest of the satellite rather less suitable, but he still had hopes. He might be short on time, but not yet on patience.
He turned his attention back to the display of Belvew’s—more correctly Theia’s—Aitoff screen, and resumed looking for ground images which might bear detailed study. Even polar areas might be usable, however less acceptable.
But watching quickly became boring, and boredom gave the pain access to his attention. He wrenched his mind back to the Titan Station, the best place to find the immediate, serious work which was almost the only thing able to keep his attention away from his body for long. Belvew was in no trouble, and the new atmospheric data seemed trivial, however interesting. There was one bit of chemistry to be rechecked, but it would be a while yet before any more data could come from Maria’s tar pools, gel pool, prebiotic reactions, or whatever they were. He hoped they would turn out to be the last, since his ripening plan practically depended on it; but he was decades past conclusion jumping or even hasty action, he hoped.
The plan itself, though still tentative, was also able to hold his attention, sometimes for a full hour. He did not cut off his connection with Theia’s screen—there was always a chance of something’s happening—but turned to another display.
The argument about atmospheric currents and polymerization had ended, and Goodell neither knew nor greatly cared how it had turned out; he was a theorist, greatly outranking Belvew, and would consider that matter when and if it became important.
The screen he now faced showed most of the scenery around Oceanus, minus a few gaps which her remaining cameras could not cover though Goodell had unobtrusively reported them. While he himself did not fly because the pain smothered his control senses too often, everyone had Waldo suits and could control the jets.
The factory was there and the ice mountain also showed. The mysterious gel area which had caused Ginger’s misadventure and had now expanded or moved to include the wreck showed only partially on the screen; this was why he didn’t know whether it was crawling or growing or even whether Oceanus was sinking in it. The last seemed quite possible from earlier experience, and Goodell badly wanted to know, but it was important to set up the preplanned part of the research program while enough of the group were still in condition to carry on routine. He didn’t want to attract attention by asking for a modification.
His project was not merely private but would be quite unacceptable to the others. It would involve breaking the agreement all had made after the unauthorized Xalco landing. It would also be a major violation of regulations, though that would mean less to practically everyone. Science had become a military discipline out of necessity, granting the necessity of saving the human species, but scientists were still individuals.
He might, of course, get his answer by luck. The third ramjet, Crius, was now on the ground with Inger—Goodell suddenly wondered how long his mind had been wandering; he had not been aware of the landing—about a hundred meters from the factory, and her cameras might supply information he wanted. At the moment they didn’t. They gave full-hemisphere view around Crius, but the craft provided too low a viewpoint for his needs.
Barn Inger had emerged and was examining the ground. There was an embarrassing gap in the factory data due solely to poor planning, and he had to fill it. He might already have seen what Goodell wanted to know but didn’t want to ask without considering it important. Maybe Inger would need to shift his ramjet, so the old man—he was nearly forty-five—kept Crius’ Aitoff image on one of his own screens and watched it closely.
Barn had noticed casually that the wreck was now on the pool rather than beside it, but motion of the tar had long ago been left for Status to keep track of. He did remember that Ginger had stuck when she walked on the glossy surface and that Belvew, on his first landing in Oceanus, had started to sink; but he had too much else to occupy his attention right now. The wreck had been powered down and allowed to cool on the local ninety-plus Kelvins; anything about it which anyone might want to check later would presumably still be there when and if the time came.
Inger’s work on the planning slip called for holes in the ground. The dirt was largely water ice, heavily laced with silicate particles and microscopic grains of polymer which had settled from the atmosphere. Physically it was rock rather than dirt. Inger was not trying to resolve fundamental questions like how the silicate had found its way up from Titan’s core or why the tars had mixed with the water instead of forming a layer on top of it. This was for theorists, later. He needed to find which of the numerous roots which the growing factory had extended in various directions corresponded to which analytical reader in the orbiting station; the roots themselves were numbered to match the instruments, but no one had thought to provide any way of telling which way a given root was extending. This, to put it mildly, was hampering the surface analysis part of the project.
Low-pressure ice—Ice—at ninety-four Kelvins is not slippery, at least not under the Titanian weight of a human being. Neither is it fragile. It is simply rock, perfectly usable for construction when pure and presumably, though no one had had a chance to try yet, still stronger though less workable when full of the hydrocarbon flour which the chemists still called “tar”. Getting a drill into it was turning out to be a problem. Barn Inger massed, in surface armor, just under a hundred kilograms; on Titan’s surface he weighed just over thirteen, less than he would have on Earth’s moon. Even with the ice not slippery he lacked both weight to make the drill bite and traction to turn it. The tool itself was powered, but at high speed it simply skittered around on the surface, while at the lowest RPM available the wielder found himself pushed sideways whenever it started to bite.
There were ice boulders from the cliff scattered around which might have provided backing, but none was in just the right spot. The proposed hole was random; Inger had located a root by microseismology before attempting any drilling. If the same instrument had been able to identify it, there would have been no trouble, but it would be necessary to drill to a point near the conduit and feed in some chemical identifiable by the factory monitors when the root picked it up.
“Can any of those ice chunks be moved?” Maria Collos asked at length. “You could build yourself some sort of backing to lean against, or even brace the drill against.” The amusement which bothered Goodell even though he did not know he had inspired it was still in her voice.
“Worth trying,” Inger admitted. He set the tool down and walked, in the awkward fashion dictated by Titan’s gravity, to a lump of ice whose volume he guessed at about a half a cubic meter. It was clear, apparently one of the fragments shattered from the nearby cliff when the factory had first been planted. He got a grip on one of the rough sides and tried to lift without success; even on Titan it must weigh seventy kilograms or so, he suddenly realized. Even at the present phase of his illness, it was too much for him in armor.
Rolling, while still awkward, was more successful, and in a few minutes the boulder was over the root. He settled it on one of its narrower sides to provide more height to lean against picked up the drill, and made another try.
Heavy as it was, the ice slab fell over as the tool made a brief, tentative bite.
“Right direction,” he said thoughtfully to the watchers, who now included even Belvew, as he picked himself up. “A pile of smaller stuff against the far side should take care of that.” The smaller stuff was plentiful and easier to carry, and in a quarter of an hour a slope of wh
at had to be thought of as rather low-density rock and gravel was bracing the back of the largest fragment.
The direction might be right but the distance had not yet been reached. Another burst of power on the drill sent the man along the wall.
It was more than an hour before the structure had grown to an acute-angled “V” with solid bracing on the outside, an inward lean on the inside to give him backing for a downward push, and a pair of small but reasonably heavy blocks which should keep his feet from slipping toward the opening of the “V.”
They didn’t and by this time Maria was not the only one being amused.
Barn Inger got back on his feet breathing heavily—not entirely from fatigue, though even the best armor still made activity difficult. His glove clicked against his face plate as he unthinkingly started to stoke his mustache.
“All right. Friction just doesn’t count even if ice isn’t slippery here. Ginger, or someone, turn Crius so her pipes point this way.”
“Better get behind your wall,” the woman promptly snapped. “A push that’ll turn the plane may be too much for your armor. I suppose you want to weld the stuff down.”
“That was the idea. I won’t get behind the pile, I’ll get away from it; then neither of us will have to worry. In fact I might as well get on board and do it myself.”
“I’m already tied in,” Ginger responded, “and you can tell better from outside when I’m lined up right and which pipe to use when I stop swivelling. They’re far enough apart so it will make a difference. How much reaction mass should we budget for this trick?” She had become just a little less impulsive, though her voice remained clipped and almost snappish.
“It shouldn’t take much, and the tanks are full. Once you’re lined up I can get right next to the wall and tell you when melting starts; you can cut off right away when I call. We could use a quarter of the juice and still have plenty for a takeoff. There’s nothing to worry about.” Barn moved away from his construction toward the left side of the jet so that the exhaust—the pilot would have to use rocket mode, of course—would reach the wall before touching him. Only a little more than a sixty degree swivel to the aircraft’s right would be needed for proper aim, not too much thrust; the ice was smooth, at least even if not slippery.
