“Precisely. I suggest you measure the distance from the nearest point now, give us the figure, and dig in again if you wish for another quarter hour. We’ll call you at that time to come out and make another measurement. I won’t be at all surprised if the dune is crawling toward you; they do that. Right, Molly? On your world, too?”
“Yes, or so I’ve read. I have no firsthand experience, and wouldn’t know what speed to expect.”
“I have.” Jenny’s tone was grim, over and above its usual grating sound.
“I am four meters from the slope, as nearly as I can judge” came Joe’s voice. “Something is starting to itch; I must dig in again.”
“Get a couple of meters farther, first,” snapped the Rimmore.
“All right.” Silence fell again. The two observers collected what data they could; Molly was a little surprised at the lack of basic instrumentation. There was no direct way to obtain wind velocity, for example. Granted that this was a spacecraft, it was also supposed to be part of a research facility. Even if the makers had not themselves been native to a planet with a reasonable atmosphere, anyone around a Leinster site—a place like Eta Carinae likely to attract pacefaring species because it was a scientific curiosity—should have at least heard of wind.
Of course, Joe hadn’t remembered it. And this was a student facility, designed to teach people not to take too much for granted, she must remember. She’d simply have to improvise. She and Jenny analyzed the gas around them, refined the work Jenny had already done on the dust/sand/snow, set up a computer watch on the inertial navigation system to get a more precise measure of the planet’s rotation rate and their latitude, located the sun by judicious selection of wavelengths in the boat’s sensors, established their present location arbitrarily as longitude zero for convenience in future work, and determined that astronomically t hey must be in the southern hemisphere. Just how far south, in both angular and linear units, would come with increasing precision over the next few minutes as the computer compared inertial data with Arc’s apparent motion.
Presently Jenny stopped work and called to Joe. “Dig out and see how far the hill is, please. 1 should have reminded you earlier but got absorbed.”
“I was thinking myself,” replied the Nethneen. “Just a moment.” It was rather more than the implied quarter of a minute, but the answer was a relief. “As far as I can tell, the slope is very little nearer—certainly not more than half a meter, and I think less. I must remember to keep a measuring device attached to my person in the future; this estimating is most unsatisfactory.”
“At least you’re not about to be buried alive,” responded Molly. “Dig in again if you want. Carol must be nearly ready to go out.”
“Just starting” came the voice of the tiny humanoid. “Charley has sealed up Joe’s armor so it won’t fill with sand before we get it to him and roped it to the robot so that it’ll stick—Joe and I may have trouble detaching it, but it won’t blow away.”
“Will you need help getting out?” asked Molly.
“No more than Charley can supply, I’d say. Watch from where you are, and make sure nothing goes wrong; you can keep Joe informed as long as I’m in sight. I’ll use one of the ports down here, as soon as Charley has his armor on, too. He’s not taking chances, either. Two or three minutes now. If you’re really as close as you think, I should be with you very quickly, Joe.”
The two observers switched active sensors to cover the ground where they expected Carol to appear, and waited, eyes on screens. There was no way to pick up the port itself, either from inside or out, and they both selected surface viewpoints a little downwind of its location—if anything did go wrong, they would catch it promptly.
Nothing did, however. “All right, close up again!” came Carol’s voice. “This thing is holding steady. Let me key in—there; one. Downwind drift at about a third of a meter a second—you should be seeing me any moment, up in Con. Let me know.”
Three or four seconds later both observers called out simultaneously. “There you are.” “Steady as a ground roller,” added Jenny. Molly was not sure whether the reference was to a vehicle or some animal native to Jenny’s world, but was equally satisfied with the situation. The robot was a vertical cylinder about a meter in diameter and three quarters as high, with the projecting rim of its field shaper forming a platform eighteen or twenty centimeter* wide around the bottom. Carol was standing on one side of this and Joe’s minor sprawled on the other, both attached with festoons of rope that looped around the entire structure. The ma-chine hung some ten centimeters clear of the ground, rock-leady in the still-violent wind; as its rider had said, its motion was perfectly smooth, controlled by its own inertial system, sensors, and drive fields. Carol’s thirty-plus kilograms on one side, poorly balanced by Joe’s empty suit on the other, did not seem to bother the drive system at all.
Molly and Jenny watched silently as the figure shrank with distance. The latter keyed in a ranging sensor and set automatic magnification to keep the image large enough for details; Molly kept her scale unchanged, preferring to see directly how Carol was approaching the dune, if dune it was, that lay downwind. It occurred to her that the robot 1might try to plow into the surface as the latter rose, but either Joe or Carol had anticipated that in the program; the Sher-vah started to ride up the hill without incident.
As she neared the top, Molly called out, “I don’t know whether you can tell slope very well from where you are, Carol, but it looks from here as though you were about to go over the edge that Joe described, if you’re really following his track. If the far side is really steep, will the robot stay upright? I don’t recall the guidance program well enough.”
“It should” came the Nethneen’s voice. “Tell me when he disappears—or Carol, you tell me when you start downhill—and I’ll dig out and watch for you.”
“I’m at the edge” was Carol’s immediate response. “The slope in front of me is very steep and loose. Sand is blowing past me and falling over—I can see why the hill is crawling toward you. Here I come.”
“Then it is a dune,” Jenny remarked with audible satisfaction.
“Not only that, it’s Joe’s dune,” replied Carol. “There he is, seventy or eighty meters to my right.”
“Can you see her, Joe?” asked Jenny.
“Not against the sky glare. It’s painful even to look up. The main question is whether she can see me, and that she’s answered.”
“Does that machine ride downhill all right?” asked Molly.
“It doesn’t know the difference,” the Shervah assured her. “I’ll be at the bottom in a few seconds. Joe, you can cover up again for a moment or two if the blowing stuff hurts; I know where you are but will have to redirect this thing. As you said, the air currents here are irregular, and I’ll have to cut the wind sensor out of the guidance plan and just travel—let’s see—this will take some time—no, not so long at that—there, that should do it. Come up again when I call out—now! Good! You can see me this time, surely.”
“Yes. Here you are. Let’s get that armor ready. Charley, did you improvise with these ropes, or do you have experience?”
“Well, I have used them before, but not very much. Is there some trouble?”
“With all due recognition that a knot should not untie itself, it should be possible for someone to untie it. This one—there, it’s coming now. Can you come around to this side yet, Carol?”