Mining the Oort

Mining the Oort

Frederik Pohl

Copyright © 1992 by Frederik Pohl

All rights reserved under International and Pan-American Copyright Conventions.
 

For Harry Harrison who made me do it

1

There isn't anything much wrong with Mars that a decent atmosphere wouldn't fix right up. Unfortunately the place hasn't got one. Looking at Mars's situation from a human point of view—and how else have humans ever looked at anything?—the mean little atmosphere Mars does have has a number of serious things wrong with it. The most important of these is that there isn't enough of it. The air pressure at the surface of the planet is a pitiful nine or ten millibars. That's so tiny that people on Earth would probably call it a vacuum, but it isn't—quite.

That's bad news for would-be ecopoiesis engineers, as the people who practice the fledgling science of transforming other planets into acceptable imitations of Earth have come to call themselves. The fact that Mars is desperately short of atmospheric gases makes their job tough, but there's good news for would-be Martian immigrants, too. The good part is that there happens to be a place in the solar system where all those volatiles that Mars so conspicuously lacks are floating around in vast quantities, going to waste.

That place isn't very handy, but that's all right. Distance doesn't matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go. The source of these potential Martian gases is way out in the fringes of the Sun's family of satellites, far beyond even Pluto; it is where comets sail forever in slow, cold orbits—at least until one or two happen to twitch themselves out of orbit and begin to slide down toward the Sun. The name of the place is the Oort cloud.

2

When Dekker DeWoe was eight years old—that was Mars-years, of course, because Dekker was a Martian and they didn't use the Earth calendar on Mars, or indeed anything else from Earth that they could possibly get along without—well, when Dekker was eight, the first comet came plunging down on Mars at the end of its weary journey out of the Oort cloud.

That was a wonderful time. It was also a scary time for young Dekker, because nothing like it had ever happened before in his life. But mostly it was wonderful because, as everybody had been saying for as long as Dekker could remember, it meant that Mars would be alive again—some day—as soon as those comets began arriving in the large numbers they surely would—some day. These days, though, the comet strike was not only wonderfully exciting, it was also a great pain in the butt. It meant turning his life upside down, because Dekker was going to have to pack up and move out of the comet's way.

Not just Dekker DeWoe and his mother, either. The whole population of the Martian deme named Sagdayev was moving, all forty-three men, women, and children, and that was definitely something for an eight-year-old to think about. It didn't
frighten
Dekker, of course. There wasn't much that frightened Dekker DeWoe. He was at an age that doesn't frighten very easily—the Earth equivalent would have been nearly fifteen—and anyway he had inherited courage from his pioneering parents. There were some things that Dekker treated with prudent respect, though—things like air leaks, or getting lost, or the Bonds—and moving his whole town belonged in that category in his mind.

The move wouldn't be permanent, though. Evacuation was just a precaution, Dekker's mother said. The comet's impact point was supposed to be way up in the Chryse Planitia, a thousand kilometers east and north of the underground mining settlement of Sagdayev, but for cautious people that wasn't quite far enough away to be safe. You didn't live long on Mars unless you made a habit of being cautious. So the Martians of Sagdayev deme weren't going to take any chances. "We don't want to be anywhere near ground zero," his mother explained, fretting over what to pack and what to abandon out of their sparse possessions. "Their aim might not be that good."

"You mean the comet might hit
Sagdayev
?" Dekker asked, his eyes opening wide.

"Oh, no," his mother said, touching him, "or at least I don't think so. Well, no, I'm sure. Really. It's just that if it came too close it could shake the town up—maybe even breach the pressure integrity." She sighed, looking fretfully around their single room. "Sometimes I think we shouldn't have built Sagdayev way out here on the edge of the Bulge, but how were we supposed to know?"

Dekker didn't answer that rhetorical question, only the one that lay behind it. "The copper's here," he pointed out.

She said absently, looking around at the clutter of possessions, "I suppose. Dekker? What about leaving Brave Bear here? You don't ever play with him anymore."

And of course Dekker admitted that he didn't. He was awed by the ruthless way his mother was discarding her own second-best shoes and his long-absent father's spare worksuit—kept only for sentiment, its air pump was old and leaky, and surely Boldon DeWoe was never going to come back to wear it again. She even threw away the little hot plate they had sometimes used to make midnight treats of cocoa or even fudge in their own room, when Dekker was little. "We can come back for some of these things later," his mother explained. "Maybe.
Probably
, Dekker. I think Sagdayev will be all right, but for now we aren't supposed to take more than twenty kilograms apiece."

It wasn't just personal possessions they were leaving behind; it was the whole underground town that had been carved with great effort out of the Martian soil. They closed down the little metal refinery and domed over the entrance to their precious copper mine. They even abandoned most of the solar mirrors and photovoltaic generators that kept all the Martian settlements powered up and alive. They harvested everything that was ripe, or nearly ripe, from the aeroponic gardens down in the deme's lowest level, but left the growing plants behind. They did not bother with the three hectares of glass-headed mushrooms that were doing their best to survive out on the slope of the long-dead volcano they had built on. They didn't even take the central kitchens and baths. There wasn't room. Four cargo carts had been dragged over from Sunpoint City, plus one pressurized cart for people. What could not fit in the carts had to stay behind.

The adults were still loading the carts up when Dekker's mother ordered him to bed on his last night in Sagdayev. Dekker certainly didn't cry. Eight-year-old Martians were much too grown-up to cry, but he had bad dreams that night, and when his mother woke him up before dawn he was bleary-eyed. She hustled him into his clothes and settled him in his metal-lath seat in the pressurized cart and left him there. Gerti DeWoe had been assigned as a relief driver, and so she had to ride in the big tractor that pulled the train of carts instead of sitting with her son.

It was a long trip to their haven in the metropolis of Sunpoint, more than eight hundred kilometers in a straight line, and they couldn't travel in a straight track. The area between the peak called Tharus Tolus, where Sagdayev had been built next to its rich vein of copper ore, and the far more impressive mountain at Sunpoint City, Pavonis Mons, was fissured and uneven. They had to take endless detours, and they didn't travel very fast at best. The solar-powered tractor was slow by nature, even with all the extra photovoltaic accumulators on the carts. And, of course, when the sun went down no more electrical power accumulated. After sunset the tractor could keep on going only as far as the stored power in its batteries would take it, leaving enough of a prudent reserve of energy to keep everyone alive and breathing until daybreak the next morning.

All in all, they were five days en route.

It was a long five days. Most of the time Dekker had little to do except sit there and eat when the meals were passed around, hand over hand, and three or four times a day get up to take his turn at the cramped little toilets. They had installed four virtuals, and when Dekker got his turn at one he could call up any kind of entertainment in the store. That was pretty good, watching old stories unroll all around him, or even catching up on his schoolwork. But that only happened for an hour or two a day. All in all, the trip was a test of their training for all the Martians from Sagdayev. If they hadn't all been schooled from birth in Manners and Consideration and Nonaggressive Interaction there might even have been fistfights. There almost were anyway—more raised voices, or angry, hissing ones, than Dekker was used to hearing, at least. But he himself was not involved in any of the petulant near-quarrels among the grown-ups.

Dekker wasn't entirely alone. Three or four times a day his mother would call him on the phone line from the tractor cab, just to chat, and between times one of her friends was right there with Dekker, because the man had taken the next seat. That was Tinker Gorshak, of course. Dekker still didn't like him, but he was glad enough to have the man's shoulder to fall asleep against sometimes.

Dekker didn't do much talking on the trip. He read his school texts when he was awake. He slept as much as he could. And, although he was really much too old for such things, he was always aware of the comforting presence of the earless, eyeless stuffed toy he had slipped into his suit at the last minute, when his mother was looking the other way. Because when push came to shove, even the nearly grown Dekker DeWoe had not been willing to let Brave Bear face the comet alone.

3

The best thing Mars had—at least, so the Martians mostly thought—was the Skyhook at Sunpoint City, and that didn't come with the planet's original equipment. It had had to be built—by Earthies, as a matter of fact, so they weren't all bad. The Skyhook had a kind of interesting history. It was one of the two critically important human inventions—the other being the Augenstein antimatter drive that made possible the fleets of spaceships that made a Skyhook worth building in the first place—which had been invented long before there was any need for either of them. In fact, the Skyhook had been invented long before there was any possibility of actually building one. The man who devised the first "space elevator" was an engineer from Leningrad named Yuri Artsutanov, and he had done it way back in 1960.

That was pretty far-sighted of Yuri Artsutanov. No human being had managed to reach even the fringe of space in 1960, and the kind of materials that you could possibly build such a thing with didn't even exist then. But it was Artsutanov who proposed that if one were to position a satellite in geostationary orbit right over a planet's equator, and hang a cable thirty-six thousand kilometers long from it, the whole lash-up would amount to an "orbital tower." Then you could run elevators up and down the cable to lift ships and cargoes and people from the planet's surface right into orbit for damn near nothing—or at least for much less than trying to do the same thing with rockets.

It all worked out just the way Artsutanov thought it would. Once the Augenstein antimatter drive came along and made spaceships fast and fairly cheap themselves, it became feasible to junket all around the solar system—once you got into orbit. But that first step was the hardest, and that was what the Skyhook was for.

Not that that first Skyhook itself had been all that cheap. The Earth one had been strung from Nairobi on the surface to geosynchronous orbit, and its construction had cost about as much as an average war. But when they came to do the same thing for Mars the price was slashed way down. The reason for that was that they didn't have to hoist all the materials that went into it from the surface of the planet to space. Mars's Skyhook
started
in space: ores from the asteroids, fabricated in orbit, made the whole thing, and then Mars was only an elevator ride from the rest of the universe. Those first daring, dedicated Martian colonists, needing everything, could then import just about anything they liked. All they had to do was pay the import bills.

4

Sunpoint City was a settlement of a whole different order from Sagdayev. Sunpoint City's mountain was the truly impressive Pavonis Mons, topping out at twenty kilometers and startling to look at, even for Martian-born Dekker DeWoe. The city sat right on the Martian equator—that was of course why it was called "Sunpoint." Therefore it was the point where the Skyhook touched down, and therefore the metropolis of the planet.

The other impressive thing about Sunpoint City was that, by Martian standards, it was
vast
. There were more than nine hundred people living in its nearly three kilometers of underground tunnels and chambers, all carved out of the soil under the Martian surface caliche and doubly sealed to keep the precious atmosphere inside.

Dekker DeWoe was awed. He had never seen so many
strangers
before. Some of them were really strange—in fact, some were not Martians at all. Sunpoint was where off-planet visitors arrived, and where many of them stayed. It held several dozen Germans, Americans, Ukrainians, Japanese, Brazilians—whole families of them—people from
Earth
! As they strolled together down one of the passageways Dekker's mother pointed a group of the Earthies out, three or four grown-ups and a couple of children. "Take a good look," she whispered. "You won't see them very often." Dekker knew why. The Earthies kept pretty much to themselves, in their own luxurious quarters.