Nearly erect now, using the alpenstocks, and never having more than one foot or stick off the ice at a time, the trio edged forward.
“I wish you would stay back,” Chile repeated when the distance had shrunk to fifty meters. “We have no data on the strength of this ice. We could be providing the heaviest load it has experienced since it formed. It would be much safer if I went forward alone and brought back whatever may be there.”
“No collecting yet, Chile,” Sheila replied. She made no comment on the danger the robot had implied, but was conscious of it. The cliff might even have an overhang. “Nothing gets moved from its original site until we make final decision about what’s coming home with us. We don’t want to spoil more than we can help for later researchers. “
The robot, who knew this perfectly well, made no reply; but both Sheila and Rob knew that First Law tension must be building up in him. They kept safely behind him as he approached the edge, the woman doing nothing to oppose her companion’s obvious intention to keep ahead of her, and stopped when they were close enough to see the far end of the projection.
There was something there. Ling had a scope-a monocular whose eye relief allowed it to be used through his face plate-but this was little help. He could tell that the object was cubical like the other finds, but much larger, seven or eight centimeters on the edge. It seemed to have been set into the dirty ice of the cliff, with two thirds of its height above the surface and an equal fraction projecting outward. The cube faces they could see appeared to be covered with regular lines of dots which sparkled faintly on their mirror-like background.
“How close do you think you can get, Chile?” the man asked at length, after Sheila had also done her best with the scope.
“Close enough to pick it up, if you wish. I can concentrate better if you stay back.”
“Don’t touch it, but examine it as closely as you can. We’ll wait here on the solid ground; I have some First Law tensions myself, now that we’re near enough to the edge to look down,” Sheila responded.
“Good. I’ll crawl, to get my head as close to it as possible. Shall I keep reporting to you as I note anything new, or merely log it as usual?”
“Don’t bother to tell us. Concentrate on observing.”
That may have been an unfortunate command, especially since both human beings were concentrating on the robot.
Chile’s “crawl” was faster than either watcher would have dared; it took him off the ground for a second or two every now and then. The surface, however, even out on the spur, was cracked and jagged enough to provide grips, so he retained control of his motion.
As he neared the end, his head hid the cube from the watchers. Ling started to move to one side to clear the view, but thought better of it after a step or two; he would have to go too far to be worth the risk.
“I have recorded everything I can sense,” Chile reported after a minute or so.
“What is it? What have you found?” Bronwen’s voice reached them.
“You report, Chile. You can tell her more than we,” ordered Sheila before Ling could start talking.
“It is a cube, six times the linear dimension of those we have found already, to the same four significant figures by which they match each other” replied ZH50. “ As far as is revealed by any radiation I can perceive, it is made of the same material. The three vertical faces I can see are covered with a pattern of-”
“Sheila! Back!”
Ling, facing sideways to keep both his companions in view, had seen the danger first, and tucked up at the sight; his cry startled the woman into a different reaction, unfortunately. She straightened slightly, and the motion carried her several centimeters upward.
The crack and bump pattern around their feet had not changed, but a new cliff had reached a height of several centimeters a couple of body lengths behind them. The woman couldn’t quite see it; she had no ground contact t? let her turn, and the face plates limited the field of view.
“Jump back! At least ten meters! The cliff face is letting go!”
Sheila lashed downward with her feet, but to no effect; it would be two or three seconds at least before she could touch ground again, and longer before she could really aim a leap even using her stick. Ling, thinking quickly, whipped his own alpenstock upward and away from her. He wasted no time watching it spin out of sight. The reaction, as he had intended, sent him drifting downward and back toward his companion.
“Pull your legs up! Be ready to kick hard when I say! I’ll aim you!”
She might have felt like objecting-she had not full confidence in his judgment, and certainly didn’t want him making any sacrifices for her-but was far too sensible to argue at such a time. Drawing up her feet, she let him drift under her.
Ling seized her ankles, and let her inertia slow his upper half, swinging his own feet back under him as their two-body system started to spin. As he had hoped-he always claimed it was a plan-his boots touched the ground closer to the edge than the common center of mass of their bodies.
“Push off!” he snapped. Sheila insisted afterward that he couldn’t really have been planning, since he knew perfectly well that her mass was much less than his. As she finished her kick he pushed upward on the ankles he still held, and simultaneously thrust with his own feet; but he jumped much too hard. As he was firmly reminded later, human legs are stronger than human arms, and there was no way his arms could transfer all the momentum his legs supplied. Some of it stayed with him as he released her. Sheila spun away from the falling surface as he had hoped, upward and back toward safety. However, instead of being still against the ice to leap again, Rob Ling was also drifting upward, out of touch with the falling block and with nowhere near the speed he had passed on to his companion.
For several seconds, however, he gave no thought to his own predicament; too much else was happening. He was spinning much more slowly than Sheila, but fast enough to get a fairly continuous view of his surroundings. At one moment he could see Chile at the tip of the spur, a second or so later the woman, now several meters above and in the opposite direction. This was all right; but on the second spin, with the new cliff face now over ten centimeters high, a thought crossed his mind.
“Chile! That cube may be smashed when it hits the bottom! Salvage it and protect it!”
The robot had obeyed literally the earlier order to concentrate on the cube, and was unaware of Ling’s danger. He took hold of the object with both hands, using his elbows as fulcrums, and tried to pull it up. It didn’t come, and the leverage started to raise his own body. However, the block gave him a good hold, when squeezed from both sides between his hands, so he was able to double up and bring his feet under him without risk of going over the edge. He placed them on each side of the specimen and began to push himself and pull it upward, increasing his force very gradually to avoid the obvious result of its suddenly breaking free. Ling watched whenever he could, with increasing tension; but before anything came of the robot’s labors, his companion’s voice distracted him.
“Rob, you moron, what were you trying to do? How are you going to get up here? Here-catch my stick!” She tried to hurl her alpenstock toward him, but her own spin betrayed her. He watched it whirl by a meter out of reach, strike the ice, and bury its sharp end in the surface.
“Relax, lady. I’ll get back down in a little while, and can jump again. Look-it’s not falling free; it must be sliding along the break. I’ll catch up.”
“When?”
“Hmmm…maybe ten or fifteen seconds.”
“How far down will the ice be by then? Will you still be able to jump that far?”
“Sure. We’ve all made bigger jumps here. The lovebirds did a forty-three-second one holding hands a couple of weeks ago, when they were celebrating their name anniversary:”
“What’s going on over there?” Bronwen’s voice came in. The Eiras didn’t really resent the geochemist’s frequent way of referring to them, since it was certainly not inaccurate, but her voice was a little sharp.
“Cliff edge broke under us. Still plenty of time to get back up,” Ling replied tersely.
“Chile! How did you-” Sheila’s voice cut in, and broke off as suddenly. Rob was facing the robot as she spoke, and saw nothing to motivate the question; there had been no visible motion by ZH50 since starting to lift. Then his body spin carried the man around to face toward cliff and woman, and the words made sense. Drifting through the vacuum only a few meters from her was a form which, in the dim light, seemed exactly like Chile.
The resemblance was mostly its black color, Rob realized almost at once; this was by far the best look he had had at the ghost. As far as general outline and size were concerned, it could have been any other member of the group. Each environment suit, however, bore a brilliant color pattern matching the team name, pale green for the Jengibres and orange for the Eiras, with black helmets for the men and white for the women. The pattern was for ease of seeing and instant recognition rather than any artistic consideration. For a moment, Ling’s bright hopes collapsed; it would have been quite possible for someone to send a group with only robots from Earth. In fact, that had been considered at some length. No ETI…