Chasm City

by Alastair Reynolds

  "Ready for what?" he said, and then realised the link to Constanza was still open. He addressed her: "You knew this trip was going ahead, didn't you?"

  "She had some idea that I'd be taking you outside," his father said, before the girl could defend herself. "That's all. You mustn't-can't-blame her for that. It's a flight outside the ship; everyone in security has to know about it, and-since we're not crossing over to one of the other ships-the reason for it."

  "Which is?"

  "To learn what happened to your mother."

  All the while they had been moving, but now they reached the freight bay's sheer metal wall. A circular door in the wall whisked open to admit them, the taxi sliding off its pallet into a long, red-lit chamber not much wider than the machine itself. They waited there for a minute or so while the chamber's air was sucked out, then the taxi moved downwards abruptly, sinking into a shaft. Sky's father took the opportunity to lean over to adjust Sky's belt, and then they were outside the ship-blackness below, and the gentle curve of the hull above their heads. The feeling of vertigo was quite intense, even though there was nothing below to suggest height.

  They dropped. It was only for an instant, but it was nauseating enough; like the feeling Sky remembered from the rare times when he had been near the ship's centre, where gravity dwindled almost to zero. Then the taxi's engines kicked in, and something like weight returned. Expertly his father vectored the taxi away from the looming grey bulk of the massive ship, adjusting their course with taps of steering thrust, his fingers as delicate on the controls as a concert pianist's.

  "I feel sick," Sky said.

  "Close your eyes. You'll be fine in a moment."

  Despite the disquiet he felt about his mother's death-and the fact that this trip had something to do with it-Sky could not completely suppress a thrill of excitement at the thought of being outside. He released the safety buckle and started clambering all around the taxi to get a better view. His father scolded him gently and told him to get back in his seat, but not with any great conviction. Then he yawed the taxi around and smiled as the great ship they had just left came into sight.

  "Well, there she is. Your home for the last ten years, Sky, and the only home I've ever known. I know; there's no need to hide your feelings. She's not exactly beautiful, is she?"

  "She's big, though."

  "She'd better be-she's just about all we'll ever have. You're luckier than me, of course. At least you'll see Journey's End."

  Sky nodded, but his father's quiet certainty that he would be dead by then could not help but make him feel sad.

  He looked back to the ship.

  The Santiago was two kilometres long; longer than any ship which had ever sailed any of Earth's oceans and easily the equal of any of the largest craft which had plied the solar system in the days before the Flotilla's departure. Her skeleton, in fact, was an old fusion-drive space freighter, retrofitted for a journey into interstellar space. With small variations, the other Flotilla ships had been converted from the same sources.

  This far from any star, almost no light fell upon the ship, and she would have been invisible were it not for the light spilling from tiny windows dotted along her length. At the very front was a big sphere encircled by lights. That was the command section, where the bridge was, and where the crew spent most of their time when they were on duty. It was where the navigational and scientific instruments were kept, forever pointed towards the destination star; the one they had nicknamed Swan, but which Sky knew really had the much less poetic name 61 Cygni A: one cool red half of a binary star system located in the random sprinkle of stars which had been given the name Cygnus in antiquity. Only towards the end of the voyage would the ship flip around to bring its tail to bear on Swan, so that it could slow itself down with exhaust thrust from the engines.

  Behind the control sphere was a cylinder of the same diameter, which held the freight bay from which they had just come. Beyond that was a long, thin spine, studded with regularly spaced modules like immense dinosaur vertebrae. At the very end of the spine was the propulsion system, the intricate and fearsome engines which had once burned to accelerate the ship up to its present cruising speed, and which would burn again on some immeasurably remote day when Sky was fully grown.

  Sky knew all these aspects of the ship; he had seen models and holograms of it many times, but it was something else to be seeing it for himself, from outside, for the first time. Slowly, but with grinding stateliness, the whole ship was rotating on its long axis, spinning to create the illusion of gravity on its curving decks. Sky watched it turn; watched lights hove into view and disappear ten seconds later. He could see the tiny aperture in the cargo cylinder, where the taxi had departed. It looked very small, but not perhaps as small as it should have done, given that this ship was all his world could ever be. Almost. He was young now, and he had only been allowed to explore a small fraction of the Santiago , but surely it would not be long before he knew it all intimately.

  He noticed something else, too; something that the models and the holos had definitely not got right. As the ship turned, it looked darker on one side than the other .

  What could that mean?

  But almost as soon as the troubling inconsistency had begun to worry him, he had forgotten it; marvelling in the sheer immensity of the ship; the pinsharp way the details held their clarity across kilometres of vacuum; trying to imagine where his favourite places in the ship mapped into this strange new view. He had never been very far down the spine, that was for certain, and even then only under Constanza's guidance, some daredevil adventure before the adults caught them. No one had really blamed him for that, however. It was natural curiosity to want to see the dead, once their existence was known.

  Of course, they were not really dead-just frozen.

  The spine was a kilometre long; half the ship's total length. In cross-section it had a hexagonal form, with six long, narrow sides. Along each of those sides were spaced sixteen sleeper modules; each a disk-shaped structure rooted to the spine by umbilical attachments. Ninety-six disks in total, and each of those disks, Sky knew, contained ten triangular compartments, each of which held a single momio sleeper and the bulky machines necessary for their care. Nine hundred and sixty frozen passengers, then. Nearly a thousand people in total, all submerged in an icy sleep which would last the entire duration of the voyage to Swan. The sleepers, needless to say, were the most precious commodity that the ship carried; its sole reason for existence. The one hundred and fifty-strong living crew were there only to ensure the wellbeing of the frozen and to keep the ship on course. Again Sky measured his current familarity with the ship against that which he could reasonably hope to attain by the time he was an adult. At the moment he knew fewer than a dozen people, but that was only because his upbringing had been deliberately sheltered. Soon he would know many of the others. His father said that there were one hundred and fifty warm humans on the ship because that was some kind of magic number in sociological terms; the population size towards which village communities tended to converge and which carried with it the best prospects for internal harmony and general wellbeing amongst its members. It was large enough to allow individuals to move in slightly different circles if they wished, but not so large that there were likely to be dangerous internal schisms. In that sense, Old Man Balcazar was the tribal leader and Titus Haussmann, with his deep knowledge of secret lore and his abiding concern for the safety of the population, chief medicine man, or top hunter, perhaps. Either way, Sky was the son of someone in a position of authority, what the adults sometimes called a caudillo , meaning big man, and that augured well for his own future. It was open talk amongst his parents and the other adults that Captain Balcazar was an "old man" now. Old Man Balcazar and his father were professionally close: Titus always had the Captain's ear and Balcazar routinely consulted Sky's father for advice. This trip outside would have required Balcazar's authorisation, since use of any of the Santiago 's spacecraft was to be kept
to a minimum, the ships themselves irreplaceable.

  He felt the taxi decelerate, false gravity easing off again.

  "Take a good look," Titus said.

  They were passing the engines: a huge and bewildering tangle of tanks and pipes and flared orifices, like the gaping mouths of trumpets.

  "Antimatter," Titus said, mouthing the word like a quiet oath. "It's the devil's own stuff, you know. We carry a small amount even in this shuttle, just to initiate fusion reactions, but even that makes me shiver. But when I think about the amount aboard the Santiago , the hairs on the back of my neck stand up."

  Titus pointed to the two magnetic storage bottles at the rear of the ship: huge reservoirs for penning macroscopic quantities of pure antilithium. The larger of the two reservoirs was empty now, the fuel it had contained completely consumed during the initial boost phase up to interstellar cruising speed. Though there was no external indication that this was the case, the second bottle still contained its complete load of antimatter, delicately balanced in a vacuum fractionally more perfect than the one through which the great ship flew. There was less antimatter in the smaller bottle, since the ship's mass would be less during deceleration than acceleration, but there was still enough to give anyone nightmares.

  No one, at least in Sky's experience, ever joked about anti-matter.

  "All right," his father said. "Now get back in your seat and do your belt up."

  When he was secure Titus gunned the taxi, increasing the thrust to its maximum. The Santiago diminished until it was just a thin grey sliver, and then became difficult to see unless one searched the starfields carefully. It was hard to believe, seeing it against apparently fixed stars, that the ship was moving at all. It was, but eight hundredths of lightspeed, though faster than any crewed ship had ever moved before, was still almost zero when set against the vast distances between the stars.

  That was why the passengers were frozen, so that they could sleep out the whole thing while three generations of crew lived almost their entire lives tending them. Cocooned in their cryogenic sleeper berths, the passengers were nicknamed mummies by the crew, momios in the Castellano which was still used for casual conversation within the ship.

  Sky Haussmann was crew. So was everyone he knew.

  "Can you see the other ships yet?" asked his father.

  Sky searched the forward view for long moments before finding one of the other vessels. It was hard to see, but his eyes must have adapted to the darkness since leaving home. Had he imagined it, even so?

  No-there it was again, a tiny, toylike constellation in its own right.

  "I see one." Sky pointed.

  His father nodded. "That's the Brazilia , I think. The Palestine and the Baghdad are out there too, but they're much further away."

  "Can you see it?"

  "Not without a little assistance." Titus's hands moved in the dark across the taxi's control board, painting an overlay of coloured lines over the window, bright against space like chalk on a blackboard. The lines boxed the Brazilia and the two more distant ships, but it was only when the Brazilia loomed large that he thought he could make out the slivers of the other two vessels. By then the Brazilia had revealed itself to be identical to his home ship, down to the disks studding its spine.

  He looked around the taxi's window, searching for an intersection of coloured lines that would demark the fourth ship, and found nothing.

  "Is the Islamabad behind us?" he asked his father.

  "No," his father said, softly. "It isn't behind us."

  There was a tone in his father's voice which troubled Sky. But in the gloom of the taxi's interior his father's expression was hard to read. Perhaps that was deliberate.

  "Where is it, then?"

  "It isn't there now." His father spoke slowly. "It hasn't been there for some time, Sky. There are only four ships left now. Seven years ago something happened to the Islamabad ."

  There was a silence in the taxi which stretched endlessly before Sky found the will to reply.

  "What?"

  "An explosion. An explosion like nothing you can imagine." His father paused before speaking again. "Like a million suns shining for the tiniest of instants. Blink, Sky-and think of a thousand people turning to ashes in that blink."

  Sky thought back to the flash he had seen in his nursery when he was three. The flash would have troubled him more if it had not been eclipsed by the way Clown broke down that day. Though he had never quite forgotten it, when he thought back to that incident, it was never the flash that was the more important thing but his companion's betrayal; the stark realisation that Clown had only ever been a mirage of flickering wall pixels. How could the brief, bright flash ever have signified something more upsetting than that?

  "Someone made it happen?"

  "No, I don't think so. Not intentionally, anyway. They might have been experimenting, though."

  "With their engines?"

  "Sometimes I think that was what it probably was." His father's voice grew hushed; almost conspiratorial. "Our ships are very old, Sky. I was born aboard our ship, just as you were. My father was a young man, hardly even an adult, when he left Mercury orbit with the first generation of crew. That was a hundred years ago."

  "But the ship isn't wearing out," Sky said.

  "No," Titus said, nodding emphatically. "Our ships are nearly as good as the day they were built. The problem is that they aren't getting any better. Back on Earth, there were still people that supported us; wanted to help us on our way. Over the years they had thought long and hard about the designs of our ships, trying to find small ways in which our lives might be improved. They transmitted suggestions to us: improvements in our life-support systems; refinements in our sleeper berths. We lost dozens of sleepers in the first few decades of the voyage, Sky-but with the refinements we were slowly able to stabilise things."

  That was news to him, too: the idea that any of the sleepers had died was not at first easy to accept. After all, being frozen was a kind of death itself. But his father explained that there were all sorts of things that could happen to the frozen which would still prevent them being thawed out properly.

  "Recently though . . . in your lifetime, at least-things have become much better. There have only been two die-offs in the last ten years." Sky would later ask himself what became of those dead; whether they were still being carried along by the ship. The adults cared deeply about the momios , like a religious sect entrusted with the care of fabulously rare and delicate icons. "But there was another kind of refinement," his father continued.

  "The engines?"

  "Yes." He said it with emphatic pride. "We don't use the engines now, and we won't use them again until we reach our destination-but if there was a way to make the engines work better, we could slow down faster when we reach Journey's End. As it is, we'll have to start our slowdown years from Swan-but with better engines we could stay in cruise mode longer. That would get us there quicker. Even a marginal improvement-shaving a few years off the mission-would be worth it, especially if we start losing sleepers again."

  "Will we?"

  "We won't know for years to come. But in fifty years we'll be very near our destination, and the equipment which keeps the sleepers frozen will be getting very old. It's one of the few systems we can't keep upgrading and repairing-too intricate, too dangerous. But a saving in flight time would always be a good thing. Mark my words-in fifty years, you'll want to shave every month possible off this voyage."

  "Did the people back home come up with a way to make the engines work better?"

  "Yes, exactly that." His father was pleased that he had guessed that much. "All the ships in the Flotilla received the transmission, of course, and we were all capable of making the modifications that it suggested. At first, we all hesitated. A great meeting of the Flotilla captains was held. Balcazar and three of the other four thought it was dangerous. They urged caution-pointing out that we could study the design for another forty or fifty years befor
e we had to make a decision. What if Earth discovered an error in their blueprint? News of that mistake could be on its way to us-an urgent message saying 'Stop'-or perhaps, a year or two down the line, they would think of something even better, but which it was not now possible to implement. Perhaps if we followed the first suggestion, we would rule out ever being able to follow another."

  Again Sky thought of the cleansing brilliance of that flash. "So what happened to the Islamabad? "

  "As I said, we'll never know for sure. The meeting broke up with the Flotilla Captains agreeing not to act until we had further information. A year passed; we kept debating the issue-Captain Khan included-and then it happened."

  "Perhaps it was an accident after all."

  "Perhaps," his father said doubtfully. "Perhaps. Afterwards . . . the explosion didn't do any serious damage. Not to us or the others, luckily. Oh, it seemed pretty bad at first. The electromagnetic pulse fried half our systems, and even some of the mission-critical ones didn't come back online immediately. We had no power, except for the auxiliary systems serving the sleepers and our own magnetic containment bottle. But in our part of the ship-up front-we had nothing. No power. Not even enough to run the air-recyclers. That could have killed us, but there was so much air in the corridors we had a few days' grace: enough time to hard-wire repair pathways and lash together replacement parts. Gradually we got things running again. We got hit by debris, of course-the ship wasn't totally destroyed in its own explosion, and some of those shards went through us at half the speed of light. The flash burned our hull shielding pretty badly, too-that's why she's darker on one side than the other." His father said nothing for a moment, but Sky knew that there was more coming. "That was how your mother died, Sky. Lucretia was outside the ship when it happened. She was working with a team of techs, inspecting the hull."

  He had known his mother had died that day-known even that she was outside-but he had never been told exactly how it had happened.