Worldmakers

by Gardner Dozois

  Yuri bent over to investigate. He slipped in the gravel and collapsed on the sensor station. The collector, antenna, trinet spokes—they all snapped off. “Asshole!” I shouted, leaping forward. It was too late. He had ruined it.

  He swore I had run into him and made him slip. He was lying, of course. I might have nudged him, but it was nothing.

  So we had to fetch parts. And strip down the sensor. And install a lot of new stuff. And check it out. We fell a full day behind schedule.

  That made Yuri even more surly. We snarled at each other when we were in the Walker. Outside, we tried to divide up the jobs so they could be done alone. We had a lot of recon work. Sensors are set up high, where sudden gully-washers won’t catch them. When a fusion Cat passes, there’s not much warning. If the just-melted slush finds a brand-new path, you’d better be out of the way.

  The third time Yuri went out he came back empty-handed. He couldn’t find his package. I walked out to it with him.

  “You know, I remember this spot,” I said. “We came by here last year. The package is right around this ledge.”

  “Well, it’s not here now.” We were standing by a shelf of yellow rock with boulders scattered around.

  “What did the map say was wrong with it?”

  Yuri looked around impatiently. “It stopped transmitting a few months ago. That’s all they know.”

  I turned to go. “Well, there’s—Wait a minute. Isn’t that a Faraday cup?”

  I bent down and picked up a little bell-like scrap of metal that was lying in the dust. “One of these is usually attached to the top of a sensor pack.”

  I looked at the nearest boulder. It must have weighed a ton, even a Ganymede. “I bet I know where our package is.”

  We found one other piece of metal wedged under the edge of boulder. I hiked back and got a replacement package. It took awhile to set up. This time we put it away from any overhang.

  Getting the package’s radio zeroed in on the base was a little tricky, since we were down in a low trough and had to relay the signals from base through the Walker’s radio at first. It took a big chunk out of the day. The next package to be checked was a long walk from our planned way station for the night. We elected to leave it for morning, but then I got restless and said I would go out to the site myself.

  Jupiter’s eclipse of the sun was just ending as I set out. I took a break to watch the sun slip out from behind Jupiter. Suddenly the planet had a rosy halo; we were looking through the outer fringes of the atmosphere. The Can was a distant twinkle of white. I walked along a streambed and in a way it was like early morning on Earth—as the sun broke out from behind Jupiter things brightened, and the light changed from dull red to a deep yellow. Everything had a clean, sharp look to it. The sun was just a fierce burning point and there were none of the fuzzy half-shadows you’re used to on Earth. Ganymede’s man-made atmosphere was still so thin it didn’t blur things.

  I felt a pop. I stopped dead. I stood still and quickly checked my suit. Nothing on my inboard monitors. My lightpipe scan showed nothing wrong on my back. Suit pressure was normal. I decided it must have been a low/energy micrometeoroid striking my helmet: they make a noise but no real damage.

  The micrometeoroid was probably some uncharged speck of dust, falling into Ganymede’s gravity well. If it had been charged, the superconductor threads woven into my suit would have deflected it. Superconductors are a marvel. Once you run a current through them, they keep producing a magnetic field—forever. The field doesn’t decay because there’s no electrical resistance to the field-producing currents. So even a one-man suit can carry enough magnetic shield to fend off the ferocious Van Allen sleet. And inside the suit there’s no magnetic field at all to disturb your instrumentation, if the threads are woven in right. The vector integrals involved in showing that can get messy, especially if you don’t know Maxwell’s equations from a mudpuddle. But the stuff works, and that’s all I needed to know.

  When I found the sensor package it needed a new circuit module in its radio; the base had guessed the trouble and told me to carry one along on the walk out. That wasn’t what interested me, though. This particular package was sitting in the middle of a seeded area. Two years ago a team of biologists planted an acre of microorganisms around it. The organisms were specially tailored in the Lab to live under Ganymede conditions and—we hoped—start producing oxygen, using sunlight and ice and a wisp of atmosphere.

  I was a little disappointed when I didn’t find a sprawling green swath. Here and there were patches of gray in the soil, so light you couldn’t really be sure they were there at all. Over most of the area there was nothing; the organisms had died.

  The trouble with being an optimist is that you get to expect too much. The fact that anything could live out here was a miracle of bioengineering. I shrugged and turned back the way I had come.

  I was almost halfway back to the Cat when I felt an itching in the back of my throat. My eyes flicked down at the dials mounted beneath my transparent view screen. The humidity indicator read zero. I frowned.

  Every suit has automatic humidity control. You breathe out water vapor and the sublimator subsystem extracts some of it before passing the revived air back to you. The extra water is vented out the back of the suit. You’d think that if the microprocessor running the subsystem failed, you’d get high humidity.

  But I had too little. In fact, none.

  I flipped down my rear lightpipe and squinted at my backpack. Water dripped from the lower vent. I checked my—

  Dripped? I looked at it again.

  That shouldn’t happen. The suit should have been venting water slowly, so it vaporized instantly when it reached the extremely thin atmosphere outside. Dripping meant the relief valve was open and all my water had been purged.

  I called up a systems review of my side viewplate, just below eye level inside my helmet. From the data train I guessed the humidity control crapout had been running for over half an hour. That was what had made the popping noise. And I had written it off as a micrometeoroid. Wishful thinking.

  I stepped up my pace. The tickle at the back of my throat meant I might have suit throat. That’s the coverall name for anything related to breathing processed air. If you get contaminants in the mix, or just lose water vapor, your throat and nose soon dry out, or get irritated. A dry throat is a feasting ground for any bacteria hanging around. If you’re lucky, the outcome is just a sore throat that hangs around for a while.

  I puffed along. In the distance I could see the faint orange aura from a fusion caterpillar. The rising mist from its roaring fusion exhaust diffused the light for tens of klicks. Blue-green shadows in the eroded hillsides contrasted with the gentle orange flow. Suddenly Ganymede felt strange and more than a little threatening.

  I was glad when the Cat came within sight. It was backed up to the way station. I clumped up the ladder and wedged through the narrow lock into the cabin.

  “You’re late for chow,” Yuri said.

  “Hope I can taste it.”

  “Why?”

  I opened my mouth and pointed. Yuri looked in, turned my head toward the light, looked again. “It’s a little red. You should look after it.”

  I got out the first aid kit and found the anesthetic throat spray. It tasted metallic but it did the job; after a moment it didn’t hurt to swallow.

  I broke down the humidity control unit in my suit. Sure enough, the microprocessor had a fault. I took a replacement chip slab out of storage and made the change. Everything worked fine.

  I was surprised at how much Yuri could do with our vac-dried rations. We had thin slices of chicken in a thick mushroom sauce, lima beans that still had some snap in them, and fried rice. We topped it off with strawberry cream cake and a mug of hot tea. Pretty damned elegant, considering.

  “My compliments,” I said. I got up from the pullout shelf that we used for a table. The room began to revolve. I put out my hand to steady myself.

  “Say!�
� Yuri shouted. He jumped up and grabbed my arm. The room settled down again.

  “I—I’m okay. A little dizzy.”

  “You’re pale.”

  “The light is poor in ultraviolet here. I’m losing my suntan,” I said woozily.

  “It must be more than that.”

  “You’re right. Think I’ll go to bed early.”

  “Take some medicine. I think you have suit throat.”

  I grinned weakly. “Maybe it’s something I ate.” I jerked on the pull ring and my foldout bunk came down. Yuri brought the first-aid kit. I sat on the bunk taking off my clothes and wondered vaguely where second aid would come from if the first aid failed. I shook my head; the thinking factory had shut down for the night. Yuri handed me a pill and I swallowed it. Then a tablet, which I sucked on. Finally I got between the covers and found myself studying some numbers and instructions that were stenciled on the ceiling of the cabin. Before I could figure out what they meant I fell asleep.

  The morning was better, much better. Yuri woke me and gave me a bowl of warm broth. He sat in a deck chair and watched me eat it.

  “I must call the base soon,” he said.

  “Um.”

  “I have been thinking about what to say.”

  “Um … Oh. You mean about me?”

  “Yes.”

  “Listen, if Captain Vandez thinks I’m really sick he’ll scrub the rest of the trip. We’ll have to go back.”

  “So I thought. Which will lower our performance ratings.”

  “Do me a favor, will you? Don’t mention this when you call in. I’m feeling better. I’ll be okay.”

  “Well—”

  “Please?”

  “All right. I don’t want this journey ruined just because you are careless.” He slapped his knees and got up. “I will make the call.”

  “Mighty nice of you,” I mumbled. I dozed for a while. I was feeling better, but I was a little weak. I thought over our route. The next way station was a respectable distance away and there was only one sensor package to visit. We would have to spend our time making tracks for the next station—which was just as well, with one crew member on the woozy side.

  “Yuri,” I said, “check and be sure—”

  “Bohles, you may be sick, but that doesn’t mean you can start ordering me around. I will get us there.”

  I rolled over and tried to sleep. I heard Yuri suit up and go out. A little later there were two faint thunks as the hoses disconnected from the way station. Then Yuri came back in, unsuited, and sat in the driver’s chair.

  The Cat lurched forward and then settled down to a steady pace. I decided to stop worrying and let Yuri handle things for a while. I was feeling better every minute, but another forty winks wouldn’t do any harm. I let the gentle swaying of the Walker rock me to sleep.

  I woke around noon; I must have been more tired than I thought. Yuri tossed me a self-heating can of corned beef; I opened it and devoured the contents immediately.

  I passed the next hour or so reading a novel. Or rather, I tried. I dozed off and woke up in midaftemoon. There was a lot of sedative in that medicine.

  I got up, pulled on my coveralls and walked over to the control board. “Walked” isn’t quite the right word—with my bunk and the table down, the Cat resembled a roomy telephone booth.

  I sat down next to Yuri. We were making good time across a flat, black plain. There was an inch or so of topsoil—dust, really—that puffed up around the Cat’s feet as they stepped. The dust comes from the cycle of freezing and thawing of ammonia ice caught in the boulders. The process gradually fractures the Ganymede rock, breaking it down from pebbles to shards to BB-shot to dust. In a century or so somebody will grow wheat in the stuff.

  Some of the soil is really specks of interplanetary debris that has fallen on Ganymede for the last three billion years. All over the plain were little pits and gouges. The bigger meteors had left ray craters, splashing white across the reddish-black crust. The dark ice is the oldest stuff on Ganymede. A big meteor can crack through it, throwing out bright, fresh ice. The whole history of the solar system is scratched out on Ganymede’s ancient scowling face, but we still don’t know quite how to read all the scribblings. After the fusion bugs have finished, a lot of the intricate, grooved terrain will be gone. Regrettable, maybe—the terraced ridges are beautiful in the slanting yellow rays of sunset—but there are others like them, on other moons. The solar system has a whole lot more snowball moons like Ganymede than it has habitable spots for people. Just like every other age in human history, there are some sad choices to make.

  Yuri sidestepped a thick-lipped crater, making the servos negotiate the slope without losing speed. He had caught the knack pretty fast. The bigger craters had glassy rims, where the heat of impact had melted away the roughness. Yuri could pick his way through that stuff with ease. I leaned back and admired the view. Io’s shadow was a tiny dot on Jupiter’s eternal dancing bands. Jove’s thin little ring made a faint line in the sky, too near Jupiter to really see clearly. You had to look away from it, so your side vision could pick it out. There was a small moon there, I knew, slowly breaking up under tidal stresses and feeding stuff into the ring. It’s too small to see from Ganymede, though. You get the feeling, watching all these dots of light swinging through the sky, that Jupiter’s system is a giant clockwork, each wheel and cog moving according to intricate laws. Our job was to fit into this huge cosmic machine, without getting mashed in the gears.

  I yawned, letting all these musings drop away, and glanced at the control board. “You do a full readout this morning?”

  Yuri shrugged. “Everything was in order last night.”

  “Huh. Here—” I punched in for a systems inventory. Numbers and graphs rolled by on the liquid display. Then something went red.

  “Hey. Hey. B and C tanks aren’t filled,” I said tensely.

  “What? I put the system into filling mode last night. The meter read all right this morning.”

  “Because you’ve got it set on A tank. You have to fill each independently, and check them. For Chrissakes—!”

  “Why is that? Was that your idea? It’s stupid to not combine the entire system. I—”

  “Look,” I said rapidly, “the Cat sometimes carries other gasses, for mining or farming. If the computer control automatically switched from A to B to C, you could end up breathing carbon dioxide, or whatever else you were carrying.”

  “Oh.”

  “I showed you that a couple days back.”

  “I suppose I forgot. Still—”

  “Quiet.” I did a quick calculation; we’d used some already—and on our present course—

  “We won’t make it to our next station,” I announced.

  Yuri kept his eyes on his driving. He scowled.

  “What about our suits?” he asked slowly. “They might have some air left.”

  “Did you recharge yours when you came back in?”

  “Ah … no.”

  “I didn’t either.” Another screwup.

  I checked them anyway. Not much help, but some. I juggled figures around on the clipboard, but you can’t sidestep simple arithmetic. We were in deep trouble.

  Yuri stepped up the Cat’s pace. It clanked and bounced over slabs of jutting purple ice. “I conclude,” he said, “that we should call the base and ask for assistance.”

  I frowned. “I don’t like to do it.”

  “Why? We must.”

  “Somebody will have to fly out here and drop air packs.” There’s always some risk with that because even Ganymede’s thin air has winds in it. We don’t understand those winds yet.

  Yuri gave me a guarded look. “An extra mission. It would not sit well with Captain Vandez, would it?”

  “Probably not.” I could tell Yuri was thinking that, when the report came to be written, he’d get the blame. “But look, the real point is that somebody back at base would have to risk his neck, and all because of a dumb mistake.”


  Yuri was silent. The Walker rocked on over the broken ground. A pinthick ammonia stream flowed in the distance.

  “You may not like it,” he said, “but I do not intend to die out here.” He reached for the radio, turned it on and picked up the microphone.

  “Wait,” I said. “I may …”

  “Yah?”

  “Let’s see that map.” I studied it for several minutes. “There, see that gully that runs off this valley?”

  “Yes. So what?”

  I drew a straight line from the gully, through the hills, to the next broad plain. The line ran through a red dot on the other side of the hills. “That’s a way station, that dot. I’ve been there before. We’re slated to check it in two days, on our way back. But I can reach it by foot from that gully, by hiking over the hills. It’s only seventeen kilometers.”

  “You couldn’t make it.”

  I worried over the map some more. A few minutes later I said, “I can do it. There’s a series of streambeds I can follow most of the distance; that’ll cut out a lot of climbing.” I worked the calculator. “Even allowing for the extra exertion, our oxy will last.”

  Yuri shrugged. “Okay, Boy Scout. Just so you leave me enough to cover the time you’re gone, plus some extra so a rocket from the base can reach me if you crap out.”

  “Why don’t you walk yourself?”

  “I’m in favor of calling the base right now. But I’ll wait out your scheme, if you want, right here. I don’t like risks.”

  “Look, if we report this, it’ll kill both our chances of staying on.”

  Yuri studied me sourly. “Probably.”

  “I don’t want to ship Earthside. It’s shit-awful back there.”

  “Uh-huh. But I like dying less.”

  “You’re just a coward, you—”

  “Cut that crap or I’ll break you in pieces, Bohles.”

  I caught myself barely in time. I felt a quick surge of energy and I knew what would happen next. But you don’t have a brawl inside a Walker, not if you ever want to use it again. So I unclenched my fists and said, “Okay, a truce. Until this problem is solved. Then, by God, I’m going to kick your face in.”