“You mean the cube may be a pure, dedicated data processor like Dumbo, telling the robot what to check but not controlling its detailed limb actions, for example.”
“A much better analogy. It is the one which occurred to me.”
“Where is its Sheila?”
“I have no basis for a guess.”
“How long has this been going on?”
“Since I left Barco. At my first leap in this direction, there was a signal burst from the robot; then it leaped from the cliff top after me.” Ling’s nod and grin were invisible inside his helmet, but his Gold partner could imagine them.
“Had the robot received a signal before following you?” asked Chispa.
“I could not tell; the cube was below my horizon.”
“But whenever you’ve been in a position to receive, such a signal preceded its action. “
“Yes. The best example came about two thirds of the way here, when I happened to be at the top of a jump. A very complex emission from the cube was followed by the robot’s ceasing temporarily to stay with me. It disappeared briefly to the right of our path, and came back carrying one of the very small cubes. It intercepted me at one of my landing points, and extended the object to me. I took it. It then took it back and placed it on top of its own head, removed it, and handed it to me again. I imitated that gesture also. The cube adhered, but not strongly; I found I could easily remove it, and decided to leave it in place.” The human beings had not noticed the minor addition to Chile’s outline, but could see it easily enough now.
“Why didn’t you-” Bronwen cut off her question; it was plain enough why Chile hadn’t reported the incident. He had been told to observe and analyze, with the implication that reporting should wait until the group had met at Big Drop.
“Have you been able to detect anything from the cube since it has been on your head?”
“Yes. It has emitted simple signals every time I move or change attitude. It is reporting my position, very precisely, to the large cube; that has been easy to work out.”
“Sure!” exclaimed Ling. “That’s what they’re all doing. It’s a sensor network analyzing topographic changes on all this part of Miranda-maybe the whole satellite. Just what we’d do if we had the gear. Someone is checking whether the surface patterns of this iceberg which have been bothering people since Voyager really represent separate fragments of a shattered body which fell back together, or internal movements, or what. The middle-sized cube on Barco is just a relay station; this one is the equivalent of Dumbo, tying all the measures together. When we learn to read its output-Keep at it, Chile!”
“I hope that’s not merely the equivalent of Chispa’s naming a cliff for a ship, or all of us calling a range of hills a dinosaur, or someone’s describing a constellation as a goat or a long-tailed bear,” Sheila responded. “We do like to fit things into patterns, don’t we, Rob?”
“Don’t be so objective. Just because I saw your face in a Rorschach blot when we were being tested for this trip, and the whole world found out about it because the tech couldn’t control her giggles, doesn’t mean-”
“Of course not,” Bronwen cut in. The blot story was not news to Dibrofiad’s personnel. “Your hypothesis is sensible, and we can keep on testing it. Chile, has this robot objected to your approaching the big cube?”
“I haven’t tried that yet. I have been working on much more direct and simple signal-action correspondence. “
Ling didn’t stop to check with the commander. “Hold up for a moment and give me that cube, then go on with your tests. I’d like to see if it gives the robot any special instructions when I get close to the center.”
“The robot can see you whether you’re wearing the cube or not, and I’m the one who’s supposed to go near the edge if necessary. I’m less likely to break a piece of it off, after all,” Sheila pointed out.
“We don’t need to worry about the cliff strength here. Would they have put this big gadget where it is without checking? Never mind the cube, Chile, but I’m going to find out-”
Bronwen was somewhat dubious, but said nothing. If Rob did cause the other robot to break off the language lesson, it would at least give some idea of the unit’s concerns and priorities. Only when the man took an unusually long step toward the cube did she utter a caution.
“It’s a long way down, Rob. I said that Sheila would be first if anyone had to go near the edge. You get set to anchor.”
Ling checked himself, a humorous sight under the local gravity and traction. “I’ll head for the right side, Sheila for the left. If one goes over, the cube will catch the chain and be a real anchorage.”
“All right. But don’t get casual.”
“I won’t. Keep an eye on Chile’s friend. I expect it’ll do something, considering how it reacted back at Barco when he tried to get the cube there. “
The whole group eased closer to the edge, Orange to the left, Green to the right, men leading by a few meters, safety chains slack.
Rob was quite right in principle, but hadn’t foreseen the detail. As he approached the right side of the block, gathering in the free chain as Sheila neared the other, the language lesson was indeed interrupted. Casually using Chile as a kick-off mass, the ghost dived straight for the man, and just as casually used his inertia to keep itself from going past the edge. The push sent Ling over, naturally, since his mass was much less than the robot’s.
The chain did not catch on the presumed data unit, for the block lifted itself smoothly a meter and a half to let the line pass underneath as Rob’s new momentum pulled it straight.
Quick planning was easy, quick execution impossible. Sheila was standing almost erect, and even though the footing was rough, could not at once leap horizontally; she had to fall to a steep angle in the desired direction first, and this had to take over a second. Pulling up her feet would be no help; she would merely fall straight and surrender what little traction she had without getting the needed tilt.
The other two teams had the same problem. Chispa and Bronwen also started down so that all four limbs could search for traction; their partners, about the same distance from the edge but closer to it than the women, leaped toward each other.
By the time they met, Chile was still helplessly drifting from the push he had received, Ling was starting to disappear below the edge, and Sheila was ready to jump away from it and him. He had released the slack in the chain connecting them.
“Hit us, Sheil’!” called Mike. She needed no instruction. A little toe work in the surface cracks headed her toward the two-man system slowly spinning and drifting edgeward as it settled toward the ground. She had bent her knees a little as she went down, and now straightened them firmly.
By the time she reached her target and complicated the system, it was on the ground. Ling was nearly out of sight, and Chile, who had had no control over his original spin, had only partly stopped his flight with his hands and was on the first bounce.
“We’ve got you, and the girls have us. There’s plenty of traction. Start hauling in!” Mike snapped. “Not too hard!”
She pulled quickly anyway. The sooner the slack was taken up and she could start doing something useful, the better. By the time she felt resistance, the falling man was out of sight, one could only estimate how far. She abandoned responsibility for her own safety to the others, and drew steadily, hand over hand, gripping the fine chain as effectively as she could with her insulated gloves. She barely noticed that the big cube had settled back where it had been. From her position, the other robot was hidden beyond it; for the moment, its possible activities didn’t concern her.
“Rob, are you all right?” she called.
“Sure. Swinging in toward the cliff now. I take it you’re anchored all right-if you come over too, it could be awkward. “
“I’m solid. Don’t look down.”
“Oh, it’s not that bad. There’s no haze to suggest distance; my head knows it’s twenty kilos, but my stomach isn’t sure it’s down. I’m about to hit the cliff; stop pulling up for a moment so I can catch it. It’s pretty rough, and I may be able to hang on myself.” There was a pause, and Sheila braced herself for a possible jolt along the chain, but felt nothing. “Missed the hold. I bounced, but only a little. I ought to get it next time. It’s not quite vertical, I think; maybe I can walk up it, with the rope helping. Here I come.” There was a pause. “Yep, it’s not straight up and down; I’m hanging against the rock. You can pull again. So much for the strength of this cliff.”
“What? Is it cracking?” Chispa was first with the question, by a split second.
“Oh, no, but if that data unit can fly, our logic was a bit shaky. Just don’t stamp, please, until I get back up. More to the point, what’s that other robot doing now?”
Chispa, who could see farthest around the right side of the cube, replied, “Nothing. It’s just standing there. Why?”