Kitabı oku: «The Complete Mars Trilogy», sayfa 10
It was getting toward the end of the long northern spring, and they still had no good supply of water, so Ann proposed to make an expedition to the cap and set up a robot distillery, along the way establishing a route that rovers could follow on automatic pilot. “Come with us,” she said to Nadia. “You haven’t seen anything of the planet yet, just the stretch between here and Chernobyl, and that’s nothing. You missed Hebes and Ganges, and you’re not doing anything new here. Really, Nadia, I can’t believe what a grub you’ve been. I mean why did you come to Mars, after all?”
“Why?”
“Yes, why? I mean there’s two kinds of activities here, there’s the exploration of Mars and then there’s the life support for that exploration. And here you’ve been completely immersed in the life support, without paying the slightest attention to the reason we came in the first place!”
“Well, it’s what I like to do,” Nadia said uneasily.
“Fine, but try to keep some perspective on it! What the hell, you could have stayed back on Earth and been a plumber! You didn’t have to come all this way to drive a goddamn bulldozer! Just how long are you going to go on grubbing away here, installing toilets, programming tractors?”
“All right, all right,” Nadia said, thinking of Maya and all the rest. The square of vaults was almost finished, anyway. “I could use a vacation.”
They took off in three big long-range rovers: Nadia and five of the geologists, Ann, Simon Frazier, George Berkovic, Phyllis Boyle and Edvard Perrin. George and Edvard were friends of Phyllis’s from their NASA days, and they supported her in advocating “applied geological studies", meaning prospecting for rare metals; Simon on the other hand was a quiet ally of Ann’s, committed to pure research and a hands-off attitude. Nadia knew all this even though she had spent very little time alone with any of these people, except for Ann. But talk was talk; she could have named all the allegiances of everyone at base if she had to.
The expedition rovers were each composed of two four-wheeled modules, coupled by a flexible frame: they looked a bit like giant ants. They had been built by Rolls-Royce and a multinational aerospace consortium, and had a beautiful sea green finish. The forward modules contained the living quarters and had tinted windows on all four sides; the aft modules contained the fuel tanks, and sported a number of black rotating solar panels. The eight wire mesh wheels were 2.5 meters high, and very broad.
As they headed north across Lunae Planum they marked their route with little green transponders, dropping one every few kilometers. They also cleared rocks from their path that might disable a robot-driven rover, using the snowplow attachment or the little crane at the front end of the first rover. So in effect they were building a road. But they seldom had to use the rockmoving equipment on Lunae; they drove northeast at nearly their full speed of thirty kilometers an hour for several days straight. They were heading northeast, to avoid the canyon systems of Tempe and Mareotis, and this route took them down Lunae to the long slope of Chryse Planitia. Both these regions looked much like the land around their base camp, bumpy and strewn with small rocks; but because they were heading downhill they often had much longer views than they were used to. It was a new pleasure to Nadia, to drive on and on and see new countryside continually pop over the horizon: hillocks, dips, enormous isolated boulders, the occasional low round mesa that was the outside of a crater.
When they had descended to the lowlands of the northern hemisphere, they turned and drove straight north across the immense Acidalia Planitia, and again ran straight for several days. Their wheel tracks stretched behind them like the first cut of a lawnmower through grass, and the transponders gleamed bright and incongruous among the rocks. Phyllis, Edvard and George talked about making a few side trips, to investigate some indications seen in satellite photos that there were unusual mineral outcroppings near Perepelkin Crater. Ann reminded them irritably of their mission. It made Nadia sad to see that Ann was nearly as distant and tense out here as she was back at base; whenever the rovers were stopped she was outside walking around alone, and she was withdrawn when they sat together in Rover One to eat dinner. Occasionally Nadia tried to draw her out: “Ann, how did all these rocks get scattered around like this?”
“Meteors.”
“But where are the craters?”
“Most are in the south.”
“But how did the rocks get here, then?”
“They flew. That’s why they’re so small. It’s only smaller rocks could be tossed so far.”
“But I thought you told me that these northern plains were relatively new, while the heavy cratering was relatively old.”
“That’s right. The rocks you see here come from late meteor action. The total accumulation of loose rock from meteor strikes is much greater than what we can see, that’s what gardened regolith is. And the regolith is a kilometer deep.”
“It’s hard to believe,” Nadia said. “I mean, that’s so many meteors.”
Ann nodded. “It’s billions of years. That’s the difference between here and Earth, the age of the land goes from millions of years to billions. It’s such a big difference it’s hard to imagine. But seeing stuff like this can help.”
Midway across Acidalia they began running into long, straight, steep-walled, flat-bottomed canyons. They looked, as George noted more than once, like the dry beds of the legendary canals. The geological name for them was fossae, and they came in clusters. Even the smallest of these canyons were impassable to rovers, and when they came on one they had to turn and run along its rim, until its floors rose or its walls drew together, and they could continue north over flat plain again.
The horizon ahead was sometimes twenty kilometers off, sometimes three. Craters became rare, and the ones they passed were surrounded by low mounds that rayed out from the rims: splosh craters, where meteors had landed in permafrost that had turned to hot mud in the impact. Nadia’s companions spent a day wandering eagerly over the splayed hills around one of these craters; the rounded slopes, Phyllis said, indicated ancient water as clearly as the grain in petrified wood indicated the original tree. By the way she spoke Nadia understood that this was another of her disagreements with Ann; Phyllis believed in the long wet past model, Ann in the short wet past. Or something like that. Science was many things, Nadia thought, including a weapon with which to hit other scientists.
Further north, around latitude 54°, they drove into the weird-looking land of thermokarsts, hummocky terrain spotted by a great number of steep-sided oval pits, called alases. These alases were a hundred times bigger than their Terran analogues, most of them two or three kilometers across, and about sixty meters deep. A sure sign of permafrost, the geologists all agreed; seasonal freezing and thawing of the soil caused it to slump in this pattern. Pits this big indicated that water content in the soil must have been high, Phyllis said. Unless it was yet another manifestation of Martian time scales, Ann replied. Slightly icy soil, slumping ever so slightly, for eons.
Irritably Phyllis suggested that they try collecting water from the ground, and irritably Ann agreed. They found a smooth slope between depressions, and stopped to install a permafrost water collector. Nadia took charge of the operation with a feeling of relief; the trip’s lack of work had begun to get to her. It was a good day’s job: she dug a ten-meter long trench with the lead rover’s little backhoe; laid the lateral collector gallery, a perforated stainless steel pipe filled with gravel; checked the electric heating elements running in strips along the pipe and filters; then filled in the trench with the clay and rocks they had dug out earlier.
Over the lower end of the gallery was a sump and pump, and an insulated transport line leading to a small holding tank. Batteries would power the heating elements, and solar panels charge the batteries. When the holding tank was full, if there was enough water to fill it, the pump would shut off and a solenoid valve would open, allowing the water in the transport line to drain back into the gallery, after which the heating elements would shut off as well.
“Almost done,” Nadia declared late in the day, as she started to bolt the transport pipe onto the last magnesium post. Her hands were dangerously cold, and her maimed hand throbbed. “Maybe someone could start dinner,” she said. “I’m almost done here.” The transport pipe had to be packed in a thick cylinder of white polyurethane foam, then fitted into a larger protective pipe. Amazing how much insulation complicated a simple piece of plumbing.
Hex nut, washer, cotter pin, a firm tug on the wrench. Nadia walked along the line, checking the coupling bands at the joints. Everything firm. She lugged her tools over to Rover One, looked back at the result of the day’s work: a tank, a short pipe on posts, a box on the ground, a long low mound of disturbed soil running uphill, looking raw but otherwise not unusual in this land of lumps. “We’ll drink some fresh water on our way back,” she said.
They had driven north for over two thousand kilometers, and finally rolled down onto Vastitas Borealis, an ancient cratered lava plain that ringed the northern hemisphere between latitudes 60° and 70°. Ann and the other geologists spent a couple of hours every morning out on the bare dark rock of this plain, taking samples, after which they would drive north for the rest of the day, discussing what they had found. Ann seemed more absorbed in the work, happier. One evening Simon pointed out that Phobos was running just over the low hills to the south; the next day’s drive would put it under the horizon. It was a remarkable demonstration of just how low the little moon’s orbit was; they were only at latitude 69°! But Phobos was only some five thousand kilometers above the planet’s equator. Nadia waved goodbye to it with a smile; she would still be able to talk to Arkady using the newly arrived areosynchronous radio satellites.
Three days later the bare rock ended, running under waves of blackish sand. It was just like coming on the shore of a sea. They had reached the great northern dunes, which wrapped the world in a band between Vastitas and the polar cap; where they were going to cross, the band was about eight hundred kilometers wide. The sand was a charcoal color, tinged with purple and rose, a rich relief to the eye after all the red rubble of the south. The dunes trended north and south, in parallel crests that occasionally broke or merged. Driving over them was easy; the sand was hard-packed, and they only had to pick a big dune and run along its humpbacked western side.
After a few days of this, however, the dunes got bigger, and became what Ann called barchan dunes. These looked like huge frozen waves, with faces a hundred meters tall and backs a kilometer wide; and the crescent that each wave made was several kilometers long. As with so many other Martian landscape features, they were a hundred times larger than their Terran analogs in the Sahara and Gobi. The expedition kept a level course over the backs of these great waves by contouring from one wave back to the next, their rovers like tiny boats, paddlewheeling over a sea that had frozen at the height of a titanic storm.
One day on this petrified sea, Rover Two stopped. A red light on the control panel indicated the problem was in the flexible frame between the modules; and in fact the rear module was tilted to the left, shoving the left side wheels into the sand. Nadia got into a suit and went back to have a look. She took the dust cover off the joint where the frame connected to the module chassis, and found that the bolts holding them together were all broken.
“This is going to take a while,” Nadia said. “You guys might as well have another look around.”
Soon the suited figures of Phyllis and George emerged, followed by Simon and Ann and Edvard. Phyllis and George took a transponder from Rover Three and set it out three meters to the right of their “road”. Nadia went to work on the broken frame, handling things as little as possible: it was a cold afternoon, perhaps seventy below, and she could feel the diamond chill right down to the bone.
The ends of the bolts wouldn’t come out of the side of the module, so she got out a drill and started drilling new holes. She began to hum “The Sheik of Araby”. Ann and Edvard and Simon were discussing sand. It was so nice, Nadia thought, to see ground that wasn’t red. To hear Ann absorbed in her work. To have some work to do herself.
They had almost reached the arctic circle, and it was Ls = 84, with the northern summer solstice only two weeks away; so the days were getting long. Nadia and George worked through the evening while Phyllis heated supper, and then after the meal Nadia went back out to finish the job. The sun was red in a brown haze, small and round even though it was near setting; there wasn’t enough atmosphere for oblation to enlarge and flatten it. Nadia finished, put her tools away, and had opened the outer lock door of Rover One, when Ann’s voice spoke in her ear. “Oh Nadia, are you going in already?”
Nadia looked up. Ann was on the ridge of the dune to the west, waving down at her, a black silhouette against a blood-colored sky.
“That was the idea,” Nadia said.
“Come on up here just a second. I want you to see this sunset, it’s going to be a good one. Come on, it’ll only take a minute, you’ll be glad you did it. There are clouds to the west.”
Nadia sighed and closed the outer lock door.
The east face of the dune was steep. Nadia carefully stepped in the prints Ann had made in her ascent. The sand there was packed and held firm most of the time. Near the crest it got steeper, and she leaned forward and dug in with her fingers. Then she was clambering onto the broad rounded crest, and could straighten up and have a look around.
Only the crests of the tallest dunes were still in sunlight; the world was a black surface, marred by short scimitar curves of steely gray. Horizon about five kilometers off. Ann was crouching, a scoop of sand in her palm.
“What’s it made of?” Nadia asked.
“Dark solid mineral particles.”
Nadia snorted. “I could have told you that.”
“Not before we got here you couldn’t. It might have been fines aggregated with salts. But it’s bits of rock instead.”
“Why so dark?”
“Volcanic. On Earth sand is mostly quartz, you see, because there’s a lot of granite there. But Mars doesn’t have much granite. These grains are probably volcanic silicates. Obsidian, flint, some garnet. Beautiful, isn’t it?”
She held out a handful of sand for Nadia’s inspection. Perfectly serious, of course. Nadia peered through her faceplate at the black grit. “Beautiful,” she said.
They stood and watched the sun set. Their shadows went right out to the eastern horizon. The sky was a dark red, murky and opaque, only slighty lighter in the west over the sun. The clouds Ann had mentioned were bright yellow streaks, very high in the sky. Something in the sand caught at the light, and the dunes were distinctly purplish. The sun was a little gold button, and above it shone two evening stars: Venus, and the Earth.
“They’ve been getting closer every night lately,” Ann said softly. “The conjunction should be really brilliant.”
The sun touched the horizon, and the dune crests faded to shadow. The little button sun sank under the black line to the west. Now the sky was a maroon dome, the high clouds the pink of moss campion. Stars were popping out everywhere, and the maroon sky shifted to a vivid dark violet, an electric color that was picked up by the dune crests, so that it seemed crescents of liquid twilight lay across the black plain. Suddenly Nadia felt a breeze swirl through her nervous system, running up her spine and out into her skin; her cheeks tingled, and she could feel her spinal cord thrum. Beauty could make you shiver! It was a shock to feel such a physical response to beauty, a thrill like some kind of sex. And this beauty was so strange, so alien. Nadia had never seen it properly before, or never really felt it, she realized that now; she had been enjoying her life as if it were a Siberia made right, living in a huge analogy, understanding everything in terms of her past. But now she stood under a tall violet sky on the surface of a petrified black ocean, all new, all strange: it was absolutely impossible to compare it to anything she had seen before; and all of a sudden the past sheered away in her mind and she turned in circles like a little girl trying to make herself dizzy, without a thought in her head. Weight seeped inward from her skin, and she didn’t feel hollow anymore; on the contrary she felt extremely solid, compact, balanced. A little thinking boulder, set spinning like a top.
They glissaded down the steep face of the dune on their boot heels. At the bottom Nadia gave Ann an impulsive hug: “Oh Ann, I don’t know how to thank you for that.” Even through the tinted faceplates she could see Ann grin. A rare sight.
After that things looked different to Nadia. Oh she knew it was in herself, that it was a matter of paying attention in a new way, of looking. But the landscape conspired in this sensation, feeding her new attentiveness; because the very next day they left the black dunes, and drove on to what her companions called layered or laminate terrain. This was the region of flat sand that in winter would lie under the CO2 skirt of the polar cap. Now in midsummer it lay revealed, a landscape made entirely of curvilinear patterns. They drove up broad flat washes of yellow sand that were bounded by long sinuous flat-topped plateaus; the sides of the plateaus were stepped and benched, laminated both finely and grossly, looking like wood that had been cut and polished to show a handsome grain. None of them had ever seen any land remotely like it, and they spent the mornings taking samples and borings, and hiking around in a loping Martian ballet, talking a blue streak, Nadia as excited as any of them. Ann explained to her that each winter’s frost caught a lamina on the surface. Then wind erosion had cut arroyos, and stripped away at their sides, and each stratum was stripped back farther than the one below it, so that the arroyo walls consisted of hundreds of narrow terraces. “It’s like the land is a contour map of itself,” Simon said.
They drove during the days and went out every evening in purply dusks that lasted until just before midnight. They drilled borings, and came up with cores that were gritty and icy, laminated for as far down as they could drill. One evening Nadia was climbing with Ann up a series of parallel terraces, half-listening to her explain about the precession of aphelion and perihelion, when she looked back across the arroyo and saw that it was glowing like lemons and apricots in the evening light, and that above the arroyo were pale green lenticular clouds, mimicking perfectly the terrain’s French curves. “Look!” she exclaimed.
Ann looked back and saw it, and was still. They watched the low banded clouds float overhead.
Finally a dinner call from the rovers brought them back. And walking down over the contoured terraces of sand, Nadia knew that she had changed – that, or else the planet was getting much more strange and beautiful as they traveled north. Or both.
They rolled over flat terraces of yellow sand, sand so fine and hard and clear of rocks that they could go at full speed, slowing down only to shift up or down from one bench to another. Occasionally the rounded slope between terraces gave them some trouble, and once or twice they even had to backtrack to find a way. But usually a route north could be found without difficulty.
On their fourth day in the laminate terrain, the plateau walls flanking their flat wash curved together, and they drove up the cleavage onto a higher plane; and there before them on the new horizon was a white hill, a great rounded thing, like a white Ayer’s Rock. A white hill – it was ice! A hill of ice, a hundred meters high and a kilometer wide – and when they drove around it, they saw that it continued over the horizon to the north. It was the tip of a glacier, perhaps a tongue of the polar cap itself. In the other cars they were shouting, and in the noise and confusion Nadia could only hear Phyllis, crying “Water! Water!”
Water indeed. Though they had known it was going to be there, it was still startling in the extreme to run into a whole great white hill of it, in fact the tallest hill they had seen in the entire five thousand kilometers of their voyage. It took them all that first day to get used to it: they stopped the rovers, pointed, chattered, got out to have a look, took surface samples and borings, touched it, climbed up it a ways. Like the sand around it, the ice hill was horizontally laminated, with lines of dust about a centimeter apart. Between the lines the ice was pocked and granular; in this atmospheric pressure it sublimed at almost all temperatures, leaving pitted, rotten side walls to a depth of a few centimeters; under that it was solid, and hard.
“This is a lot of water,” they all said at one point or another. Water, on the surface of Mars …
The next day the glacier hill formed their right horizon, a wall that ran on beside them for the whole day’s drive. Then it really began to seem like a lot of water, especially as over the course of the day the wall got taller, rising to a height of about three hundred meters. A kind of white mountain ridge, in fact, walling off their flat-bottomed valley on its east side. And then, over the horizon to the northwest, there appeared another white hill, the top of another ridge poking over the horizon, the base remaining beneath it. Another glacier hill, walling them in to the west, some thirty kilometers away.
So they were in Chasma Borealis, a wind-carved valley that cut north into the ice cap for some five hundred kilometers, more than half the distance to the Pole. The chasm’s floor was flat sand, hard as concrete, and often crunchy with a layer of CO2 frost. The chasm’s ice walls were tall, but not vertical; they lay back at an angle less than 45°, and like the hillsides in the laminate terrain, they were terraced, the terraces ragged with wind erosion and sublimation, the two forces that over tens of thousands of years had cut the whole length of the chasm.
Rather than driving up to the head of the valley, the explorers crossed to the western wall, aiming toward a transponder that had been included in a drop of ice-mining equipment. The sand dunes mid-chasm were low and regular, and the rovers rolled over the corrugated land, up and down, up and down. Then as they crested a sand wave they spotted the drop, no more than two kilometers from the foot of the northwest ice wall: bulky lime green containers on skeletal landing modules, a strange sight in this world of whites and tans and pinks. “What an eyesore!” Ann exclaimed, but Phyllis and George were cheering.
During the long afternoon, the shadowed western iceside took on a variety of pale colors: the purest water ice was clear and bluish, but most of the hillside was a translucent ivory, copiously tinted by pink and yellow dust. Irregular patches of CO2 ice were a bright pure white; the contrast between dry ice and water ice was vivid, and made it impossible to read the actual contours of the hillside. And foreshortening made it hard to tell how tall the hill really was; it seemed to go up forever, and was probably somewhere between three and five hundred meters above the floor of Borealis.
“This is a lot of water,” Nadia exclaimed.
“And there’s more underground,” Phyllis said. “Our borings show that the cap actually extends many degrees of latitude farther south than we see, buried under the layered terrain.”
“So we have more water than we’ll ever need!”
Ann pursed her mouth unhappily.
The drop of the mining equipment had determined the site of the ice mining camp: the west wall of Chasma Borealis, at longitude 41°, latitude 83° N. Deimos had just recently followed Phobos under the horizon; they wouldn’t see it again until they returned south of 82° N. The summer nights consisted of an hour’s purple twilight; the rest of the time the sun wheeled around, never more than twenty degrees above the horizon. The six of them spent long hours outside, moving the ice miner to the wall and then setting it up. The main component was a robotic tunnel borer, about the size of one of their rovers. The borer cut into the ice, and passed back cylindrical drums 1.5 meters in diameter. When they turned the borer on it made a loud, low buzz, which was louder still if they put their helmets to the ice, or even touched it with their hands. After a while white ice drums thumped into a hopper, and then a small robot forklift carried them to a distillery, which would melt the ice and separate out its considerable load of dust, then refreeze the water into one-meter cubes more suitable for packing in the holds of the rovers. Robot freight rovers would then be perfectly capable of driving to the site, loading up and returning to base on their own; and base would then have a regular water supply, larger than they could ever use. Around four or five trillion cubic kilometers in the visible polar cap, Edvard calculated, though there were a lot of guesses in the calculation.
They spent several days testing the miner and deploying an array of solar panels to power it. In the long evenings after dinner Ann would climb the ice wall, ostensibly to take more borings, although Nadia knew she just wanted away from Phyllis and Edvard and George. And naturally she wanted to climb all the way to the top, to get on the polar cap and look around, and take borings of the most recent layers of ice; and so one day when the miner had passed all the test routines, she and Nadia and Simon got up at dawn – just after two a.m. – and went out into the supercold morning air and climbed, their shadows like big spiders climbing before them. The slope of the ice was about 30°, steepening and then letting off time after time as they ascended the rough benches in the hill’s layered side.
It was seven a.m. when the slope laid back and they walked onto the surface of the polar cap. To the north was a plain of ice that extended as far as they could see, to a high horizon some thirty kilometers away. Looking back to the south they could see a great distance over the geometric swirls of the layered terrain; it was the longest view Nadia had ever had on Mars.
The ice of the plateau was layered much like the laminated sand below them, with wide bands of dirty pink contouring across cleaner stuff. The other wall of Chasma Borealis lay off to the east, looking almost vertical from their point of view, long, tall, massive: “So much water!” Nadia said again. “It’s more than we’ll ever need.”
“That depends,” Ann said absently, screwing the frame of the little borer into the ice. Her darkened faceplate turned up at Nadia: “If the terraformers have their way, this will all go like dew on a hot morning. Into the air to make pretty clouds.”
“Would that be so bad?” Nadia asked.
Ann stared at her. Through the tinted faceplate her eyes looked like ballbearings.
That night at dinner she said, “We really ought to make a run up to the pole.”
Phyllis shook her head. “We don’t have the food or air.”
“Call for a drop.”
Edvard shook his head. “The polar cap is cut by valleys almost as deep as Borealis!”
“Not so,” Ann said. “You could drive straight to it. The swirl valleys look dramatic from space, but that’s because of the difference in albedo between the water and the CO2. The actual slopes are never more than 6° off the horizontal. It’s just more layered terrain, really.”
George said, “But what about getting onto the cap in the first place?”
“We drive around to one of the tongues of ice that drop to the sand. They’re like ramps up to the central massif, and once there, we drive right to the pole!”
“There’s no reason to go,” Phyllis said. “It’ll just be more of what we see here. And it means more exposure to radiation.”
“And,” George added, “we could use what food and air we do have to check out some of the sites we passed on the way up here.”
So that was their point. Ann scowled. “I’m the head of the geological survey,” she said sharply. Which may have been true, but she was a horrible politician, especially compared to Phyllis, who had any number of friends in Houston and Washington.
“But there’s no geological reason to go to the pole,” Phyllis said now with a smile. “It’ll be the same ice as here. You just want to go.”
“Well?” Ann said. “Say I do! There are still scientific questions to be answered up there. Is the ice the same composition, how much dust – everywhere we go up here we collect valuable data.”
“But we’re up here to get water. We’re not up here to fool around.”
“It’s not fooling around!” Ann snapped. “We obtain water to allow us to explore, we don’t explore just to obtain water! You’ve got it backwards! I can’t believe how many people in this colony do that!”
Nadia said, “Let’s see what they say at base. They might want us to help with something there, or they might not be able to send a drop, you never know.”
Ann groaned. “We’ll end up asking permission from the UN, I swear.”
