by Hal Clement
The mechanic rose from in front of the panel, and turned to Ken.
“I’m going to sleep for a while,” he said. “I’ll be back before arrival time. In case you care, you’ll be making the first landing. It takes one and a half revolutions of Planet Three, more or less, to get the torpedo there when the planets are in their present relative positions—we can’t use overdrive on the drones—and the signal must have come during the local daytime. I’ll see you. Have me paged if you want me for anything.”
Ken gave the equivalent of an affirmative nod.
“All right—and thanks. Your name is Allmer, isn’t it?”
“Right—Feth Allmer.” Without further speech the mechanic disappeared through the door, moving with the fluid ease of a person well accustomed to Mercury’s feeble gravity, and leaving Sallman Ken in a very thoughtful mood behind him.
Almost unconsciously the investigator settled onto the rack deserted by Allmer, and stared blankly at the indicators in front of him. One of his troubles, he reflected ruefully, was his tendency to get interested in two problems at once. In one way, that might be good, of course; the genuine absorption in the problem of Planet Three was the best possible guard against suspicion of his other job; but it didn’t help him to concentrate on that other. For hours now he had thought of practically nothing but his test project, until Allmer’s parting remarks had jarred him back to duty.
He had assumed Allmer was a competent technician, but somehow he had not expected the acuity the elderly fellow had just displayed. Ken himself had missed the implication of Drai’s statement concerning the habits of the natives of the third planet; apparently Drai had not even thought of doing his own reasoning.
But could he be that stupid? He, unlike Ken, knew the distances involved in a flight to that world, and the speed of the torpedoes; he had, on his own word, been trading here for years. What purpose could he have in trying to appear more stupid than he really was?
One possibility certainly existed. Ken might already be under suspicion, and facing a conspiracy to make him betray himself by overconfidence. Still, why in that case had the mechanic betrayed his own intelligence? Perhaps he was building himself up as a possible confidant, in case Ken were to grow communicative. If that were so, Feth was his greatest danger, since he was most in Ken’s company and in best position to serve as a spy. On the other hand, the fellow might be completely innocent even if the group as a whole were engaged in smuggling, and his recent words might have been motivated by a sincere desire to be helpful. There seemed no way of telling at the moment which of these possibilities was the more likely; Ken gave the problem up for the moment as insoluble with the data on hand.
The other problem was demanding his attention, anyway. Some of the indicators on the board in front of him were fluctuating. He had learned the panel fairly well in the last day or two, and was able to interpret the readings himself. It seemed, he noted, that pressure and temperature were both going down in the cargo chamber of the projectile. Well, that was reasonable. There were no heaters working, and the pressure would naturally drop as the gas cooled. Then it occurred to him that the temperature of Planet Three was low enough to freeze sulfur, and his test units would be covered with a crust of the stuff. Something should be done about that.
As a matter of fact, most of the pressure drop was due to leakage; the cargo door had cooled and contracted sufficiently to let air escape slowly around its edges. Ken, however, did not think of that; he found the appropriate switch and tripped it, watching the pressure drop instantly to zero as the door opened. The temperature was almost unaffected—if anything, it dropped more slowly, for the recording pyrometers were now insulated by a vacuum and the expansion of the gaseous sulfur into empty space had had no cooling effect to speak of. A touch on some of the switches which were designed to heat the test substances showed that the little furnaces were still in working order, and after a moment’s thought Ken allowed the magnesium and titanium specimens to come up to melting temperature. Then, sure that they were as free of contaminating gases as could be managed, he watched the recorders as the samples cooled again. Through all this, the torpedo hurtled on, unaffected by the extra drain on its power.
For some minutes Ken continued to wait, one eye roving over the dials and the other glancing casually about the great room; but finally he decided that Allmer had picked a good time to go off duty. He did not feel tired himself, but gradually he became convinced that there must be something a little more constructive to do. He suspected that, even if there were to be any drugs around the station, they would not have arrived yet, so there was no use making a search for them; but preparations might be made to see just what came back in the other torpedo.
As a first step, it might be well to go up to the observatory to find out just who was guiding that missile. If it were Drai himself, it would be a point in favor of Rade; if not, it would be another person from whom information might be obtained. There seemed little doubt that no one would be allowed to run the trading torpedo who did not know exactly what was being obtained on the third planet—the Planet of Ice, as Ken was coming to think of it (not that he thought of ice as a substance; he had never seen the material and would have thought of it as hydrogen oxide in any case. Planet of Solid Sulfur comes closer to the way he would have expressed the thought).
Ken was basing his supposition on his memory of how Drai had refrained from naming the substance obtained from the planet; and, determined to find at least one small brick of data to add to his edifice of information, the investigator headed up the spiral ramp toward the observatory at the station’s highest level. No one attempted to stop him on the way, though he met a couple of workers who flipped tentacles in casual recognition. The door of the observatory was not locked, as a trial push showed, and he entered, still without opposition. He was braced for a prompt request to depart, and was a little surprised when nothing at all was said. A moment later, when his eyes had become accustomed to the dimness of the big room, he realized to his chagrin that no one was there.
“No business secrets loose so far,” he muttered.
He was about to return the way he had come, when it occurred to him that he might as well make sure of that fact. There were not many places where paper work of any sort could be kept, at least at first glance; and these he rapidly covered. They were mostly cabinets built under instrument panels, and seemed to contain nothing but tables of the motions of the planets of this system. These seemed rather valueless; their most probable use would be in navigation, and Ken could not imagine anyone’s wanting to navigate anywhere in this system except to the world of Ice. They could also be used to direct the instruments, if anyone wanted to look at the planets in question; but that seemed even less helpful.
Under the beam setting controls was a small drawer which also contained two sets of numbers—again, spatial coordinates; but this time Ken froze to attention as he realized that one set at least did not refer to planets—they contained no cyclic term. The set was short, consisting of six groups of numbers containing from six to ten digits each; but he recognized them. The first identified by spectrum a beacon star; the next three were direction cosines, giving the three-dimensional bearing to another sun; the fifth gave a distance. Normally he might not have recognized or remembered the lengthy figures; but those were the coordinates of the blazing A-class sun which warmed Sarr, his home planet. The final number was another range; and beyond question it represented the distance from the present point of observation to the listed star. Ken knew enough of the standard navigational notations to be sure of that.
The other set of numbers, then, must give the direction of the same sun relative to some local set of coordinates; and not only was he ignorant of the coordinates, but the numbers were too long to remember. To copy them would be suicide, if anything more than commercial secrecy were involved. For long minutes Sallman Ken stood frozen in thought; then, abruptly, he slipped the sheet back into the drawer, closed the latter, an
d as quickly as was compatible with caution left the observatory. Since the information was there, it would not do for anyone to get the idea he had been there for any great length of time. It would be better if no one knew he had been there at all, but he had been seen on the way up the ramp. He proceeded to get back to his own quarters and assume an attitude of repose, though his mind still raced furiously.
He knew his distance from home. Evidently the twenty-two days of the journey to this system had not been spent in straight-line flight; the distance was only two hundred twelve parsecs. Score one for Rade; that would be an expensive business precaution, but a normal criminal one.
The direction home from this system he did not know. It did not matter too much anyway; what the Narcotics Bureau would want would be the opposite direction, on Galactic coordinates, and there would be no mathematical connection between the two except a purely arbitrary formula which would be harder to memorize than the direction itself.
Of course, the beacon listed in the stellar coordinates was probably visible from here; but could he recognize it with any certainty without instruments? The instruments were available, of course, but it might not be wise to be caught using them. No, orientation was definitely the last job to be accomplished in his present location. At any rate, one fact had been learned and one point of probability had been added to the Rade theory. Sallman Ken decided that made a good day’s work, and allowed himself to relax on the strength of it.
VI.
Nearly three of Sarr’s thirteen-hour days passed uneventfully before the relay station circling Earth picked up the approaching torpedoes. As Feth Allmer had predicted—and Laj Drai had confirmed, after checking with his tables—the signals from the planted homing unit were coming from the dark side of the planet. Drai phoned down from the observatory to the shop, where Ken and Allmer were engaged in decelerating their missile.
“You may as well drop straight down as soon as you swing around to the dark side,” he said. “You will pick up the beacon if you spiral in, keeping between forty and fifty-five degrees above the plane of the planet’s orbit, measured from the planet’s center. The beam can be picked up by your torpedo more than forty diameters out, so you can’t possibly miss it. You’d better ride the beam down automatically until you’re into atmosphere, then go manual and move off a couple of miles if you plan to go all the way to the ground. If the natives are camping near the beam transmitter, it would be a pity to touch off your chemicals right in their midst.”
“True enough,” Ken replied. “Feth is swinging around into the shadow now, still about five diameters out. I wish there were a vision transmitter in that machine. Some time I’m going down close enough to use a telescope, unless someone builds a TV that will stand winter weather.”
“You’ll get worse than frostbite,” Drai responded sincerely. “The time you were really looking at that world, you didn’t seem quite so anxious to get close to it.”
“I hadn’t gotten curious then,” responded Ken.
The conversation lapsed for a while, as Feth Allmer slowly spun the verniers controlling the direction of thrust from the torpedo’s drivers. The machine was, as Ken had said, cutting around into the shadow of the big planet, still with a relative speed of several miles per second to overcome. Allmer was navigating with the aid of a response-timer and directional loop in the relay station, whose readings were being reproduced on his own board; the torpedo was still too far from Earth for its reflection altimeter to be effective. For some minutes Ken watched silently, interpreting as best he could the motions of the flickering needles and deft tentacles. A grunt of satisfaction from the operator finally told him more clearly than the instruments that the beam had been reached; a snaky. arm promptly twisted one of the verniers as far as it would go.
“I don’t see why they couldn’t power these things for decent acceleration,” Feth’s voice came in an undertone. “How much do you want to bet that we don’t run all the way through the beam before I can match the planet’s rotation? With nine-tenths of their space free for drivers and accumulators, you’d think they could pile up speed even without overdrive. These cheap—” his voice trailed off again. Ken made no reply, not being sure whether one was expected. Anyway, Allmer was too bright for his utterances to be spontaneous, and any answer should be carefully considered purely from motives of caution.
Apparently the mechanic had been unduly pessimistic; for in a matter of minutes he had succeeded in fighting the torpedo into a vertical descent. Even Ken was able to read this from the indicators; and before long the reflection altimeter began to register. This device was effective at a distance equal to Sarr’s diameter—a trifle over six thousand miles—and Ken settled himself beside the operator as soon as he noted its reaction. There was not far to go.
His own particular bank of instruments, installed on a makeshift panel of their own by Allmer, were still idle. The pressures indicated zero, and the temperatures were low—even the sodium had frozen, apparently. There had been little change for many hours—apparently the whole projectile was nearly in radiative equilibrium with the distant sun. Ken watched tensely as the altimeter reading dropped, wondering slightly whether atmosphere would first make itself apparent through temperature or pressure readings.
As a matter of fact, he did not find out. Feth reported pressure first, before any of Ken’s indicators had responded; and the investigator remembered that the door was shut. It had leaked before, of course, but that had been under a considerably greater pressure differential; apparently the space around the door was fairly tight, even at the temperature now indicated.
“Open the cargo door, please,” Ken responded to the report. “We might as well find out if anything is going to react spontaneously.”
“Just a minute; I’m still descending pretty fast. If the air is very dense, I could tear the doors off at this speed.”
“Can’t you decelerate faster?”
“Yes, now. Just a moment. I didn’t want to take all night on the drop, but there’s only about twenty miles to go now. You’re the boss from here in.” The needle of the altimeter obediently slowed in its march around the dial. Ken began warming up the titanium sample—it had the highest meeting point of all. In addition, he was reasonably sure that there would be free nitrogen in the atmosphere; and at least one of the tests ought to work.
At five miles above the ground, the little furnace was glowing white hot, judging from the amount of light striking the photocell inside the nose compartment. Atmospheric pressure was quite measurable, though far from sufficient from the Sarrian point of view, if the Bourdon gauge could be trusted; and Feth claimed to have worked out a correction table by calibrating several of them on the dark side of Planet One.
“Can you hold it at this height for a while?” Ken asked. “I’m going to let this titanium act up here, if I possibly can. There’s atmosphere, and we’re high enough not to be visible, I should think.” Allmer gestured to the reading of the photocell.
“The door is open, and that furnace is shining pretty brightly. You’d do better to shut the door, only that would keep air pretty well out. A light like that so far from the ground must show for scores of miles.”
“I never thought of that.” Ken was a trifle startled. He thought for a moment, then, “Well, let’s close the door anyway. We have a pressure reading. If that drops, we’ll know that some sort of action is taking place.”
“True enough.” Allmer snapped the toggle closing the door and waited silently while Ken manipulated his controls. Deprived of the opening through which a good deal of heat had been radiating, the compartment temperature began to climb. By rights, the pressure should have done the same; but to Ken’s intense satisfaction, it did not—it fell, instead. At his request, the door was opened for an instant and promptly closed again; results were consistent. The pressure popped back to its former value, then fell off once more. Apparently the titanium was combining with some gaseous component of the surrounding atmosphere,
though not violently enough for the reaction to be called combustion.
“If you’re far enough to one side of the beam, let’s go down to the surface,” the investigator finally said. “I’d like to find out what percentage of the air will react this way, and for any sort of accuracy I’ll need all the atmospheric pressure I can get to start with.”
Feth Allmer gave the equivalent of a nod.
“We’re a couple of miles to one side,” he said. “I can drop straight down whenever you want. Do you want the door open or closed?”
“Closed. I’ll let the sample cool a little, so we can get normal pressure after landing without using it all up. Then I’ll warm it up again, and see how much of the air in the compartment is used up.” Feth gestured agreement, and a faint whistling became audible as the torpedo began to fall without power—like the others, it had speaker and sound pickups, which Allmer had not bothered to remove. Four miles—three—two—one—with deceptive casualness, the mechanic checked the plunge with a reading of one hundred fifty feet on the altimeter, and eased it very cautiously downward. As he did so, he gestured with one tentacle at another dial; and Ken, after a moment, understood. The projectile was already below the level of the homing station.
“I suppose the transmitter is on a mountain, and we’re letting down into a valley,” Feth elaborated, without taking his eyes from his work.
“Reasonable enough—this was always supposed to be a rough section of the planet,” agreed Ken. “It’s good— there’s that much less chance of being visible from a distance. What’s the matter—aren’t you down, after all?”
The altimeter had reached zero, but nothing had checked the descent. Faint rustlings had become audible in the last few seconds, and now these were supplemented by louder snappings and cracklings. Descent ceased for a moment. Apparently an obstacle sufficient to reflect radar waves and take the machine’s weight had been encountered; but when a little downward drive was applied, the crackling progress continued for some distance. Finally, however, it ceased—noise and motion alike—even when Allmer doubled and quadrupled the power for several seconds. He opened his drive switches and turned to Ken with a gesture equivalent to a shrug.
