"We're tide locked to Saturn,” she said, instead, dealing with the second question first. “So the day's the same as the orbital period.” I knew that much, but this time I bit my tongue and was rewarded by having her cut straight to the chase. “It's afternoon here, but we've still got at least seventy-two hours of light."
"And the canister?"
"Over there somewhere.” Then she realized that without an external interface, there was no way to point. “Okay, turn around, about a hundred fifty-five degrees."
I did a near one-eighty, to my right.
"Oh, damn"—I'd never heard her swear before—"I meant the other way. You usually turn counterclockwise. No, don't turn back. See the ridge off to the right, the one that looks like a sleeping alligator? Not that one, the one next to it. No, now you've overshot. Don't move, let's figure this out. Right now, I'd give my eyeteeth for a way to point."
"Not much of an offer.” It was the closest I could come to apologizing for shutting her up earlier. “Given that the only teeth in the vicinity are mine."
"Yes, but you love figures of speech.” In other words, Apology accepted.
"What if—” I started, but she was ahead of me.
"Okay. All I've got to work with are your eyes. So, scan the horizon slowly to the left, and I'll tell you when you've got it."
It, when I found it, didn't look much like an alligator, but then I've never had that type of imagination.
"So the canister's up there?” I had no idea how far away the ridge was. Five kilometers? Ten? I shouldn't have shut off her trig lesson, but I had too much pride to admit it. It looked walkable. No lakes, and the dunes got progressively smaller until they gave way to something that, from here at least, looked firm.
Then Brittney burst my bubble. “No, that's just the direction. Give or take a bit. We went through a couple of major wind shifts on the descent, and it's hard to figure out exactly how they would have affected the canister. The only thing I'm sure of is that it's heavier than we are, with a lot less chute-per-mass. So it had to come down faster, which puts it somewhere over there.” She gave a very humanlike pause. “Unless something weird happened. We left the door open and that will have produced some oddities in the drag. Without better data"—again the pause—"it's just an educated guess."
Uh-oh. Though if I had to trust my life to someone's educated guess, Brittney's was better than mine. “How far?"
"I'm more sure of the direction than the distance. We opened the hatch way too soon."
That had become obvious when we'd spent the better part of the past two hours riding the chute down here. The problem had been that we'd stolen the canister's stabilizing chute, which meant that the canister was going to come down faster than normal. How much faster required all kinds of technical data that wasn't available, and ... well, with no telemetry and nothing but Brittney's back-of-the-envelope calculations to go on, I'd been really gung-ho on popping the hatch earlier rather than later. At least we could look outside. Then, the canister had started swaying wildly and there was nothing to see but cloud, which might or might not end before we hit the ground. We'd argued a bit, but whatever else Brittney controlled, she didn't control my muscles, and I sure as hell wasn't going to die in that damn can. So we jumped. Then we'd drifted forever.
"How far?” I asked again.
"Surface winds on Titan usually aren't over a couple kilometers per hour,” she said, in the same not-quite-talking-about-it manner she uses for Enceladus. “But we seem to have come down in the middle of what passes for a gale."
I watched sand particles skitter across the dune. “So what is it, fifteen or twenty kilometers?"
"Uh-uh. The winds were stronger, higher up. I don't know how fast we were going before we dropped below the clouds, but the total drift could easily be eighty klicks. Maybe a hundred and twenty. Somewhere in there."
Uh-oh, indeed. If I'd kept up my ground-rat muscles, an eighty-kilometer hike in low grav probably wouldn't have been too tough. Even a hundred twenty might not have been all that bad. Assuming we could even find the canister. As it was...
I took a deep breath, like a swimmer preparing to dive, or an actor trying to dispel the butterflies.
"Yep,” Brittney said. “Time to get this show on the road. You walk; I'll give you landmarks to steer by.” She was chattering again—more of that AI adrenaline stuff, I suppose. “Once we got low enough to see it, I did my best to map the terrain. The main things to worry about are box canyons. That and lateral drift. That's when, walking a compass line, you always veer in the same direction around trees. Of course we don't have a compass and there aren't any trees, but the canyons'll cause the same problem...."
* * * *
Thirty minutes later, I was still slogging through dunes. Well, not quite slogging: I clearly didn't have full ground-rat strength, but I wasn't as weak as I feared. As best I could tell, I had half-gee strength, which on a one-seventh-gee world was like being able to tote around a hundred or so kilos, back on Earth.
Long ago, when I really was a ground rat, I'd carried some heavy packs into some pretty remote places. Here, at least, I only had my own reduced weight, plus a few kilos for the suit. But soft, windblown sand is soft, windblown sand. If you try to run, it sucks the energy right out of you.
At first, I tried for some form of the old lunar shuffle, but it just didn't work. Every time I'd pick up a decent amount of speed and start to find the rhythm, I'd hit a supersoft spot and trip. In low grav you still have full momentum, so the result tended to be a nasty combo belly flop and faceplant.
After about a dozen of those, I gave up and remembered what I knew of soft surfaces from my backpacking days on Earth, which is basically that fighting them doesn't do anything but wear you out. But I'd never been in a situation like this before, where each step was a metronome, clicking away what little remained of my life.
Patience has never been Brittney's strong suit either. It's probably got something to do with the difference in our internal clock speeds. I think in terms of seconds, but she's got the ability to work in femtoseconds, or maybe something smaller yet.
For most purposes, she adjusts quite well. Talking to me, for example, she's very good at acting, at least, as though she's thinking in real time. Most likely, she actually is; even nonsentient personality interfaces require a humungous amount of processing time. She also has the ability to use variable-speed processing to make conversations more natural. But if she's obsessing about something—well, let's just say that there are a lot more femtoseconds in a second than most people have seconds in a lifetime.
"We're never going to make it at this pace,” she said, just as we were finally reaching the end of the sand.
"Hopefully, we'll speed up."
"It's not speed I'm worried about."
"What, then?"
"Life support. As best I can figure, you've done about four kilometers. But you've used up a lot more than four percent of the air. And you're using water even faster."
"I was thirsty, damn it.” I could see the gauges as well as she could. The suit carried two liters of water; I'd drunk a tenth of it. In a pressure suit, that would be no problem; it would just recycle. Here, I was breathing bone-dry O2 and venting excess water vapor along with CO2, through the selective permeability membrane in the suit's skin. Not much I could do about it.
"Look,” I said, “I may not be able to do spherical trig in my head, but I know a thing or two about deserts.” And even though this place was colder than Hell, it certainly looked like a desert. “Rationing water doesn't work. Trust me, you just get tired sooner. The best approach is to drink what you need until you run out."
Then of course, you have no choice but to suffer, which is why everyone is so desperate to save the last drops. But physiologically, that's counterproductive.
"Trust me,” I said again, mostly to reassure myself.
"How do you know all that?"
"It doesn't matter. I just do."
; She surprised me by accepting that. “Okay. But water's not the main problem."
"No kidding."
"Hey—"
Damn. I'd hurt her again. Hell, it wasn't her fault the ship had hit a rock. It was mine for not having upgraded the sensors. It's just that rocks like that are so incredibly rare, and there's never enough money to go around, so I'd bought the skinsuit instead. Which was good, given that we had hit a rock, but not hitting the rock would have been better.
If you start playing that kind of what-if, though, you can chase yourself in circles forever. Whatever psychological quirks the license-board shrinks thought they'd found in me—and I've never met a solo-boat pilot without a few—getting caught up in the what-if game isn't one. If I'd been prone to it, I'd have found a hundred and one ways to blame myself for my parents’ deaths and probably never have made it out of childhood alive. I'd come close enough, as it was.
I knew what I needed to say, but couldn't form the words. “Yeah,” I said, in what was at least an acknowledgement I'd been off base. “Tell me about the air."
When we'd left the ship, I'd topped off the suit to a full charge of compressed gas. It really was a state-of-the-art suit, which meant it carried the air in monomembrane bladders behind my back, shins, thighs, etc. They left my joints free to move but made me look like a gene-freak bodybuilder. I did not want to think what would happen if one of those bladders burst; I'd probably shoot off like a punctured birthday balloon, leaving my heirs with one great lawsuit against the manufacturer. If I'd had any heirs to notice I was gone.
Brittney was slow to answer, and it dawned on me that she was wrestling with a whole new level of feelings. “You've been using it kind of fast,” she said at last.
I checked the gauge for the umpteenth time, but it was still pretty close to full.
"Specifically,” she said, “you've used 7.3 percent of your oxygen for only five percent of the minimum possible distance."
I stared again at the gauge. “You can read it that accurately?” It was a simple dial, ticked off in hash marks. Fancier gauges exist, but too many spacers have died from a surfeit of numbers. Good, okay, not so good, get the hell home. For most stuff, that's all you need.
"No, the suit's telemetered. It took me a bit to find the wavelength, and it would have been nice if you'd had time to hook up the medical stuff, but there's all kinds of technical info, including instantaneous airflow. Thanks for getting it for me. In other circumstances it would be lots of fun."
I'd been continuing to walk, but that last comment almost caused me to break stride. For the first time, I found myself really wondering what life looked like from Brittney's perspective. Maybe the little-girl thing and my own I'm-going-to-reprogram-you threats had had me fooled. I knew she was alive in a way few computers achieve, but I'm not sure how strongly I'd ever really felt it.
Hell, I'd not had a chance to use the skinsuit before and didn't even know it was so well telemetered. The idea that it might matter to Brittney had never occurred to me.
"You're welcome,” I said, hoping it didn't sound too much like an afterthought.
* * * *
We walked in silence, while I thought about Brittney and oxygen, and tried not to think about death.
Ahead, her alligator hill rose closer, looking more like a mountain than a hill. Though without trees or people for scale, everything tends to loom large.
"Okay,” Brittney said as we stepped off the last of the sand onto rounded stones that weren't a whole bunch easier to walk on. “We don't actually want to climb that thing. Veer left and go up the gully.” Again the pause. “I hope.” More pause. “My map's not all that good."
"It's not your fault I couldn't see much,” I said. Or that I'd not had time to rig any kind of decent instrumentation for her, like radar. She'd been doing everything by dead reckoning. If we lived, it was going to be because she was very good at it. If we died, it would be my fault for getting the suit rather than upgrading the ship. And she thought I'd gotten it as a toy for her. Crap. “Do the best you can,” I added. “That's all anyone can ever ask."
She was silent for about ten paces. “Thanks.” More paces. “I mean it."
If I'd been on Earth, I'd have described the stones as river cobbles. Brittney's gully was thirty meters wide, with multiple scour channels and more of those rounded cobbles underfoot. In the Old Mojave, I'd have called it a “wash."
In the desert, washes are a mixed blessing. Sometimes, they're like highways, but they're tricky because it takes amazingly little to stop you cold. Brittney had mentioned box canyons, but a boulder jam or a two-meter ledge is all it takes. Well, in this gravity, maybe a bit more than two meters. But I'd rather not have to test my leaping ability.
Nor are washes the easiest places to walk, though on Earth, the footing tends to get easier as you climb. Luckily, that worked here, too. Lots of small, ankle-twisting stuff down low. Bigger, firmer stuff as we went—I guess I'll call it inland. Still, I wasn't managing anything faster than a sort of bouncy walk.
As in the dunes, I couldn't believe how familiar the landforms appeared. “It looks like it flash floods here,” I said. “Frequently."
"I wouldn't worry about it. Mars has river channels. It hasn't rained there for a while."
"Good point.” I'd not really been worried, but Brittney had been unusually subdued, and there was no harm in letting her talk a bit. “Rain here must be pretty damn weird."
"Liquid methane. And those cliffs over there that look like granite?"
"Yeah?"
"They're probably ice. A lot of these uplands are cryovolcanoes.” Again she surprised me because that's all she said. In the old days—gads, was it only this morning?—she would have carried on for twenty minutes about the details of cryovolcanoes, when she damn well had to know that I knew the basics. Pretty much like earthly volcanoes, except that the lava was ammonia-water slush that was only hot in climates like this.
I found myself puffing harder and glanced back. Hard to tell, but from the glimpse I could see of distant sand, V-ed in the notch of the canyon walls, it looked like we'd ascended quite a bit.
"How are we doing on air?” I asked.
Brittney must have been waiting for the question. “Better, but still unsustainable. Initially, you were making six kilometers per hour, with a maximum range of sixty, assuming no rest breaks, which seems unlikely. You've upped it to eight or nine kilometers per hour, but you're burning gas at the same rate, so your range is still under a hundred. And this gully keeps curving back and forth, so not all of those klicks are in the right direction."
"In other words, this isn't going to work."
"I didn't say that."
"No, I did.” I stopped and sat on a boulder. Or a big ice cube. Gads, how can a place so familiar looking be so weird?
I knew what I had to do, but first I wanted to deal with another problem.
Most of my life, I've been alone. Now, I was with someone who depended on me, whether I liked it or not. Someone who could think in femtoseconds and had way too many of those in which to worry. But someone who'd synched her pace of life to mine, which meant that when she thought about the air running out, it wasn't simply a bazillion femtoseconds away, it was ... well, tomorrow, for her as for me.
What she needed was something more to do than study a fuzzy map, watch my air, and worry that she might be leading us to our deaths. It would be even better if I could make her believe it was useful.
"Do you know what a MET is?” I asked.
"Uh, no. Should I?"
"No, it's not spacer stuff.” I sighed and stood up. The wash here was too steep for what I had in mind. Hopefully I'd not waited too long; having to backtrack would be a disaster.
"It's basically the amount of oxygen you're consuming at rest."
"Zero?"
"Very funny.” Actually, the joke was a good sign. Maybe she wasn't as disheartened as I'd feared. “Okay, the amount that I consume. How precise is that telemetry?"
"Moderately. Right now you're using 980 milliliters of oxygen per minute. It's been as high as three liters."
That would have been when I was killing myself, trying to get up that dune. “What's the lowest?"
"When you were resting, it dropped to 320 but it was still going down."
"Okay. Let's say 250; for my body size it should be somewhere in that vicinity."
"That means you'd last about sixty-four more hours, sitting on a rock. Maybe more if you fell asleep."
"Good. You're getting the idea. At twenty METs, we'd have a bit less than three and a half hours.” Not that anyone could sustain that pace. “At ten"—which once upon a time I could sustain for quite a while—"the air would last twice as long."
"Okay. Now, you're up to 4.7, but you're barely doing seven klicks per hour."
"That's because the terrain's getting rougher."
I was getting very nervous about the wash. I didn't care if it was formed by a methane river carving through cryovolcanic ammonia-water ice, it was narrowing and getting steeper, and those were not good signs. An unclimbable ledge was a very real risk. Hell, maybe we'd find a waterfall with a pool of stagnant methane at its base. Even if it didn't rain very often, it must take the stuff forever to evaporate. I guess I could nerve myself to wade a small pool if I had to, but wading and boulder clambering would be slow, hard going.
"So that's your job,” I said, though really all I'd done was give her a new number to play with. “Help me find the effort level that gives the biggest bang for the buck."
"I can tell you right now that that wasn't the first hour."
"Of course not! We were on sand." And those damn cobbles in the lower part of the wash. My turn to pause. “You won't like the next bit either."
Ahead, the wash was choked with boulders the size of the supply canister. On Earth, I'd never get through without a rope. Here ... well, I'd rather not have to try. It looked too much like the type of place where things might fall on you.
Analog SFF, June 2007 Page 3