“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.