“Hm-m-m. The more I think, the more I remember that there isn't enough fuel on the Moon to get a rescue tractor out here, even if anyone knew we were in trouble and could make the trip in time. Still — wait a minute; you said something just then. What was it?”
“I said all my ideas dealt with maps, but…'
“No; before that.”
“I don't recall, unless it was that crack about damp rags, which we don't have.”
“That was it. That's it, Shan; we don't have any rags, but we do have water.”
“Yes — inside our spacesuits. Which of us opens up to save the other?”
“Neither one. Be sensible. You know as well as I do that the amount of water in a closed system containing a living person is constantly increasing; we produce it, oxidizing hydrogen in the food we eat. The suits have driers in the air cycler or we couldn't last two hours in them.”
“That's right; but how do you get the water out? You can't open your air system.”
“You can shut it off, and the check valve will keep air in your suit — remember, there's always the chance someone will have to change emergency tanks. It'll be a job, because we won't be able to see what we're doing, and working by touch through spacesuit gauntlets will he awkward as anything I've ever done. Still, I don't see anything else.”
“That means you'll have to work on my suit, then, since I don't know what to do after the line is disconnected. How long can I last before you reconnect? And what do you do, anyway? You don't mean there's a reservoir of liquid water there, do you?”
“No, it's a calcium chloride drier; and it should be fairly moist by now — you've been in the suit for several hours. It's in several sections, and I can take out one and leave you the others, so you won't suffer from its lack. The air in your suit should do you for four or five minutes, and if I can't make the disconnection and disassembly in that time I can't do it at all. Still, it's your suit, and if I do make a mistake it's your life; do you want to take the chance?”
“What have I to lose? Besides, you always were a pretty good mechanic — or if you weren't, please don't tell me. Get to work.”
“All right.”
As it happened, the job was not started right away, for there was the minor problem of finding Shandara to be solved first. The two men had been perhaps five yards apart when their faceplates were first blanked out, but neither could now be sure that he hadn't moved in the meantime, or at least shifted around to face a new direction. After some discussion of the problem, it was agreed that Shandara should stand still, while Ridging walked in what he hoped was the right direction for what he hoped was five yards, and then start from wherever he found himself to quarter the area as well as he could by length of stride. He would have to guess at his turns, since even the sun no longer could penetrate the layer of dust on the helmets.
It took a full ten minutes to bump into his companion, and even then he felt undeservedly lucky.
Shandara lay down, so as to use the minimum of energy while the work was being done. Ridging felt over the connection several times until he was sure he had them right — they were, of course, designed to be handled by spacesuit gauntlets, though not by a blindfolded operator. Then he warned the cartographer, closed the main cutoffs at helmet and emergency tanks to isolate the renewer mechanism, and opened the latter. It was a simple device, designed in throwaway units like a piece of electronic gear, with each unit automatically sealing as it was removed — a fortunate fact if the alga culture on which Shandara's life for the next few hours depended was to survive the operation.
The calcium chloride cells were easy to locate; Ridging removed two of the half-dozen to be on the safe side, replaced and reassembled the renewer, tightened the connections, and reopened the valves.
Ridging now had two cans of calcium chloride. He could not tell whether it had yet absorbed enough water actually to go into solution, though he doubted it; but he took no chances. Holding one of the little containers carefully right side up, he opened its perforated top, took a specimen bag and pushed it into the contents. The plastic was not, of course, absorptive — it was not the first time in the past hour he had regretted the change from cloth bags — but the damp crystals should adhere, and the solution if there was any would wet it. He pulled out the material and applied it to his faceplate.
It was not until much later that he became sure whether there was any liquid. For the moment it worked, and he found that he could see; he asked no more. Hastily he repeated the process on Shandara's helmet, and the two set out rapidly for the rim. They did not stop to pick up camera or map.
Travel is fast on the Moon, but they made less than four hundred meters. Then the faceplates were covered again. With a feeling of annoyance they stopped, and Ridging repeated the treatment.
This time it didn't work.
“I supposed you emptied the can while you were jumping,” Shandara remarked in an annoyed tone. “Try the other one.”
“I didn't empty anything; but I'll try.” The contents of the other container proved equally useless, and the cartographer's morale took another slump.
“What happened?” he asked. “And please don't tell me it's obvious, because you certainly didn't foresee it.”
“I didn't, but it is. The chloride dried out again.”
“I thought it held onto water.”
“It does, under certain conditions. Unfortunately its equilibrium vapor pressure at this temperature is higher than the local barometer reading. I don't suppose that every last molecule of water has gone, but what's left isn't sufficient to make a conductor. Our faceplates are holding charge again — maybe better than before; there must be some calcium chloride dust on them now, though I don't know offhand what effect it would have.”
“There are more chloride cartridges in the cyclers.”
“You have four left, which would get us maybe two kilos at the present rate. We can't use mine, since you can't get them out; and if we use all yours you'd never get up the rim. Drying your air isn't just a matter of comfort, you know; that suit has no temperature controls — it depends on radiation balance and insulation. If your perspiration stops evaporating, your inner insulation is done; and in any case, the cartridges won't get us to the rim.”
“In other words you think we're done — again.”
“I certainly don't have any more ideas.”
“Then I suppose I'll have to do some more pointless chattering. If it gave you the last idea, maybe it will work again.”
“Go ahead. It won't bother me. I'm going to spend my last hours cursing the character who used a different plastic for the faceplate than he did for the rest of these suits.”
“All right,” Tazewell snapped as the geophysicist paused. “I'm supposed to ask you what you did then. You've just told me that that handkerchief of yours is a good windshield wiper; I'll admit I don't see how. I'll even admit I'm curious, if it'll make you happy.”
“It's not a handkerchief, as I said. It's a specimen bag.”
“I thought you tried those and found they didn't work — left a charge on your faceplate like the glove.”
“It did. But a remark I made myself about different kinds of plastic in the suits gave me another idea. It occurred to me that if the dust was, say, positively charged…'
“Probably was. Protons from the sun.”
“All right. Then my faceplate picked up a negative, and my suit glove a positive, so the dust was attracted to the plate.
“Then when we first tried the specimen bag, it also charged positively and left negative on the faceplate.
“Then it occurred to me that the specimen bag rubbed by the suit might go negative; and since it was fairly transparent, I could…'
“I get it! You could tie it over your faceplate and have a windshield you could see through which would repel the dust.”
“That was the idea. Of course, I had nothing to tie it with; I had to hold it.”
“Good enough. So you got a good idea out of an idle remark.”
“Two of them. The moisture one came from Shan the same way.”
