Phase Space

by Stephen Baxter

  Maybe that will be the last she’ll hear of my voice. Because I was still sightseeing when everything fell apart.

  I don’t know what went wrong. It happened too fast. My best guess is my reaction-control system, little peroxide thrusters, was misaligned. I remembered that ding in the fuel line –

  I came in too fast. I tried to turn. I even restarted the fusion pulse drive, but it wasn’t enough.

  One of the spinning mountains came sweeping up, inexorable, to swat the Malenfant like a fly.

  Before the impact, I closed up my fubar suit and bailed out.

  The solar panels crumpled, and I saw cells tumble away, little black discs the size of my palm. When my hab module hit it cracked open right down a leaky Russian weld. The drive unit kept working, for a while; it lurched away from the surface, spinning crazily. Other fragments were bounced off the surface, the gravity too low to make them stick: pieces of my ship, scattering into trans-Jovian space.

  It took a long time for 624 Hektor to reel me in.

  I landed like a dust mote. My boots crunched on lightly-compacted regolith. It felt like loose snow.

  I walked towards the wreck. The gravity was so low I kept tumbling away from the ground, as if I was suspended on some huge bungee cord.

  Malenfant was fubar, as we used to say in the Army: fucked up beyond all recognition. Just as well I had my fubar suit, I thought.

  The stars wheeled around me.

  The next day it was her mother’s turn.

  Green Wave, three days old, was an adult herself now, and her growing pains had diminished. Not her hunger, though. And not her anger.

  She stood with Churning Wake at the edge of the water, over her mother’s body. ‘Why does it have to be like this?’

  ‘It just is,’ said Churning Wake.

  ‘But she lived only a few days. In two, three, four days, it will be your turn, Churning Wake. And mine. It isn’t right. It isn’t enough.’

  ‘But it’s all we have. It’s all there’s ever been.’ He took her hand. ‘Accept it. Be calm.’

  ‘Like hell.’

  After a time, he let her hand go.

  A Worker slid through the water, its wake oily. It clattered up the curving shoreline of Finger Hall, and loomed over her mother’s corpse. It trailed a fine net which was crammed with algae. It raised up a glinting limb, which started to descend towards her mother’s body.

  Green Wave lunged forward and grabbed the limb. It was cold and hard, its edges sharp. She twisted. There was a crunching noise, and the limb came away from its socket. Green Wave staggered back, breathing hard. There was a steady ticking from somewhere inside the Worker’s algae-crusted case.

  Sun Eyes grabbed her shoulders. A day older, her brother already looked closer to death than life, she thought.

  ‘What are you doing?’

  ‘Why do they take away the dead?’ she snapped. ‘Why do they take away our food? We don’t have enough to eat. If we had more to eat, maybe we’d live longer.’

  He looked doubtful. ‘How long?’

  ‘I don’t know.’ She struggled with the concept. ‘Ten days. Maybe twenty.’

  ‘Twenty days? That’s ridiculous.’

  The Worker had come forward again, and was sawing industriously at her mother’s cadaver. It didn’t seem impeded by the loss of its limb.

  ‘You have to let her go,’ said Sun Eyes.

  Green Wave looked at him bleakly.

  When the beach was clean of traces of her mother the Worker slid back towards the water. The stump, where she had torn away the limb, trailed cables. The Worker sank beneath the water and began to surge towards the darkness at the end of Finger Hall.

  The people clattered back into the water, to resume their endless feeding.

  Green Wave, carrying her Worker limb, started to wade along the river.

  Churning Wake stood on the bank, watching her. ‘Where are you going?’

  ‘I want to see where it’s taking all our food.’

  ‘What about us?’

  She laughed. ‘Come with me.’

  ‘No,’ he said. ‘This is my place. We only have a few days. It’s up to us not to waste it.’

  That made Green Wave hesitate.

  What if he was right? Wasn’t she gambling away what little was left of her life? Did she really want to risk it all, chasing the unknown?

  Maybe she should take time to think this out.

  She looked back at Churning Wake, the ribs poking out of his skinny frame. A new infant came crawling past his bony legs, struggling to stand. It was Sun Eyes’ son, her nephew, a grandchild her mother had never seen. His wife was already dead.

  There had to be, she thought, more than this.

  ‘Come with me,’ she said again.

  Churning Wake ignored her. He strode into the water and started to feed, with steady determination.

  Her brother stood hesitating.

  ‘Sun Eyes? Please?’

  ‘You’ve been trouble since you were born.’

  ‘I’m sorry.’

  He walked into the water.

  Side by side, they waded through the shallow water, feeding on filtered handfuls of algae paste. Before long, the little community was just a knot of motion in the dim light of the distance. Nobody called them back. They walked on into the cold and dark.

  The fubar suit is a smart design. I read the Owner’s Manual, which scrolled across the inside of my faceplate.

  A fubar suit is a miniature life-support system in itself. It has a small plutonium-based power supply, heavily shielded. It is full of nanotechnology. It could recycle my wastes, filter my water, break down the solid residue, even feed me on the blue-green algae which would grow in the transparent, water-filled outer layers of the suit.

  When I walked across the surface of 624 Hektor, I sloshed and sparkled green. Neil Armstrong would have hated it.

  The suit could keep me alive – oh, for two or three weeks. It’s a hell of a technical achievement.

  Beyond that timescale, it just isn’t practical to preserve a full-scale human being in a closed skin-tight container.

  Even so, the fubar suit had fallbacks. More drastic options. Mostly untested; the Owner’s Manual said I would be voiding manufacturers’ guarantees if I exercised them.

  I put it off.

  I toured 624 Hektor.

  With the low gravity it is easy to bound around the equator of either of the little peanut twins. The curvature is tight; I could see I was on a compact ball of rock, curved over on itself, suspended in space. There are craters, some a couple of kilometres across, as if this was a scale model of Luna. Everywhere I found black, sooty carbon compounds, like a dark snow over the regolith.

  I hiked around to the contact region.

  624 Hektor is a toy world, but even so it is big. I was clambering over a sloping landscape, approaching a hundred-mile mountain that was suspended impossibly over my head, grounded in a broad region of mushed-up regolith and shattered rock.

  I lost my sense of the vertical. I actually threw up a couple of times – me, the great astronaut – but some kind of biochemical process inside my helmet cleaned me out.

  I could leap from one worldlet to the other.

  My perspective shifted. Suspended halfway between the two halves of the peanut, I got a brief sense that these were, indeed, two miniature planets, joined at the hip. But then the other half of the pair started to open out, into a dusty, broken lunar landscape. Real Peter Pan stuff.

  I wished I could show it to my kid.

  The Worker surged steadily along the length of Finger Hall.

  Gradually the walls opened out around them, smooth and high, receding into the distance. At last they reached a new chamber, much wider and higher than Finger Hall. It was roughly circular, and its roof let in the sunlight. A compact lake lapped at its floor, thick with algae.

  There were no people here, but more corridors led off from the rim: five narrow tubes like Finger Hall, and on
e much broader and darker.

  ‘It’s just as they said,’ Sun Eyes said. ‘This is the Palm Cavern: the Hand from which five Fingers sprout.’ He held up his own hand. ‘Just like a human hand. And look – that larger tunnel is like a Wrist, leading to an Arm –’

  ‘Maybe.’

  The Worker was heading out of the lake, in a new direction. Towards the Wrist.

  ‘We have to go on,’ Green Wave said.

  ‘I’m too old for this, Green Wave. Maybe we should go back. Anyhow, nobody’s ever been up there before.’

  ‘Then we’ll be the first.’

  She took his hand and all but dragged him into the water.

  The Worker surged silently along the broader corridor that was the Arm, its roof so far above them – seventy, eighty times their height – it was all but impossible to see. There were more Workers here, swimming precisely back and forth along the Arm.

  Green Wave and Sun Eyes tired quickly. They were spending so much time just moving, they weren’t feeding enough.

  The Worker stopped. It was completing small, tight circles in the water, scooping up algae with its trailing nets.

  Bringing Sun Eyes, Green Wave moved steadily closer, until the Worker came within an arm’s length.

  Green Wave grabbed onto the net it trailed. She lodged the detached Worker limb in strands of the net. She helped Sun Eyes get a close grip on the net.

  The Worker didn’t seem to notice. It wasn’t moving so fast; it was easy to hold onto the net, and let the Worker just pull her through the water.

  The Worker resumed its steady progress upstream. Some of the net was worn, and she was even able to reach inside and haul out handfuls of algal paste to feed them both.

  The walls of the Arm slid steadily past, remote and featureless. On the long beaches there were no signs of people. Maybe, she thought, her own people were alone here, however far this branching series of tunnels and gloomy lakes continued.

  Sun Eyes slept for a while. His hair, thinning and straggling, drifted into his eyes; Green Wave brushed it back.

  The Worker turned a wide corner, and the river opened out. Now they entered a new chamber, containing a broad, glimmering lake, many times wider than the Palm Cavern they’d seen before. The roof here, far above them, was all but transparent, and Green Wave could see the sun’s small disc, and many lesser lights. The water was thick with algae; she merely had to dip her hand in to pull out great fistfuls of sticky paste.

  ‘Fingers,’ she said.

  ‘What?’

  ‘Fingers. A Hand. An Arm. If that’s all true, this must be the Chest. Or the Stomach.’

  ‘You don’t know what you’re talking about,’ Sun Eyes said tiredly.

  ‘If I’m right, that way must be the Head.’

  ‘The Head of what?’

  ‘How should I know?’

  In the direction she pointed, there was a broad, dark exit. The Neck? A series of thick pipes snaked out of the lake, and passed into the Neck. There was a system of net hoppers in front of the pipes; the water was greener there, as if richer with algae. Workers clustered around the hoppers, working busily, dumping in algae from their own nets. She pictured some prone giant, sucking nutrient out of this algal hopper in its Stomach.

  Sun Eyes clutched at the net. ‘We’re leaving the shore. I can’t feel the floor.’

  It was true. The Worker was forging its way across the lapping surface of the lake; they were already a long way from the curving walls, heading for the deeper water under the high arch of the Stomach roof.

  And now there was something new. Something deep under the water. It was a light, flickering, bubbling. No: a bank of lights, in neat rows, stretching off all around her.

  ‘What do you think it is?’ she whispered.

  ‘I don’t know. I only ever saw lights in the sky.’

  ‘Maybe it’s another sun, under the water. Maybe –’

  But now a hatch on top of the Worker’s back was opening up. A limb came looping over, and plucked objects out of the hatch. The objects, dried-up and irregular, were the remnants of Green Wave’s mother. The Worker dumped them into the water.

  They fell quickly, but when they hit the underwater suns there was a ferocious, silent bubbling.

  ‘So that’s what happens to dead people,’ said Sun Eyes.

  ‘That’s what will happen to us.’

  The hatch closed, and the Worker swam in lazy, broadening circles.

  ‘I’m tired,’ Sun Eyes said.

  She fed him more handfuls of algal paste.

  I lay on my back, face up to the stars, unsure if I would ever get up again.

  I let the nems get to work.

  I wish I could say it was painless.

  The idea is simple.

  The fubar suit has constructed a stable, simplified, long-duration ecosphere inside itself. Most of the volume is just air, but there is a shallow water lake pooling in the suit’s back, arms and legs. There is blue-green algae growing in the lake, feeding on sunlight, giving off carbon dioxide – spirulina, according to the Owner’s Manual, full of proteins, vitamins and essential amino acids. The other half of the biocycle is a community of little animals, living inside the suit. They are like humans: eating the algae, drinking the water, breathing in oxygen, breathing out carbon dioxide. Their wastes, including their little dead bodies, go to a bank of SCWOs – supercritical water oxidizers – superhot liquid steam which can oxidize organic slurry in seconds. A hell of a gadget. It can even sustain underwater flames; you have to see it to believe it.

  Of course you can’t close the loops completely. But I was able to plug the suit into the surface of 624 Hektor and supplement the loops with raw materials – carbon compounds, hydrates. It would last a long time.

  It’s all constructed and maintained by the nems – nano-electro-mechanical systems, tiny crab-like robots with funny little limbs. The suit is full of them. They’re even burrowing their way out into the asteroid surface, in search of raw materials.

  I read all about the nems in the Owner’s Manual. The technology is neat; the nems are run by chips lithographed by high-energy proton beams, and they store data in chains of fluorine and oxygen atoms on the surface of dinky little diamonds –

  I always liked Japanese gadgets.

  But I should stick to the point.

  Little guys. Of course they are like miniature people. What else could they be? They are made out of me.

  There’s no nice way of putting this. The fubar suit couldn’t keep me alive – not as sixty kilograms of eating, breathing, excreting woman anyhow. So the nems took me apart.

  The nems used my body water to make the lakes, and my meat – some of it – to make the little guys.

  What’s left of me is my head. My head is sustained – my brain is kept alive – by nutrients from the little biosphere that takes up the space my body used to occupy. One day, the theory goes, the medics will retrieve me and will reassemble me, in some form, with more nanotech.

  It’s grotesque. Well, it’s not what I wanted. I’m only thirty-eight years old. I have a kid, waiting for me.

  I just didn’t have any choices left.

  The fubar suit was a last resort. It worked, I guess.

  I just wish they’d tested it first. Damn those Japanese.

  Little humans. They are supposed to look like us, bug-sized or not. They are supposed to be able to move around; the water surfaces in there are doped somehow, so the little guys aren’t locked in place by surface tension. They are supposed to breed quickly and eat and breathe and die back, and just play their part in the two-component biosphere, keeping me alive.

  What they’re not supposed to be is smart. What they’re not supposed to do is ask questions.

  What a mess.

  When she woke, she was so stiff it was all she could do to unhook her claw-like hands from the net. Sun Eyes was still sleeping, shivering gently. His scalp was all but hairless now, his face a mask of wrinkles.

 
She looked around. The Worker was close to the shore of this great Stomach cavern, but it was working its way back towards the exit from which it had emerged.

  Time to get off, she thought.

  She shook Sun Eyes. His eyes were crusted with sleep. ‘Green Wave? I can’t see so well. I’m cold.’

  ‘Come on. I’ll get you to the shore.’

  She helped him disentangle himself from the netting. His legs unfolded from his chest with painful slowness.

  At last they were standing, in water that came to their waists. She slid an arm around him, and they walked to shallower water, scooping up algae. Green Wave still carried her purloined Worker limb.

  The Worker, apparently oblivious to the loss of its passengers, surged steadily towards the exit to the Arm.

  ‘It’s going back,’ Sun Eyes said.

  ‘I know. We have to go on.’

  ‘What for?’

  ‘I’m not sure.’

  ‘Where?’

  She pointed. ‘That way. The Head.’

  They began to work their way around the complex, sculpted shoreline, towards the exit Green Wave had labelled the Neck. They walked in the shallows. They could only manage a slow pace, such was Sun Eyes’ condition.

  She felt a deep stab of regret. She’d taken Sun Eyes away from where he should be, with his children and grandchildren. And she was old herself now – too old to have a life of her own, too old for children. She wondered what had happened to Churning Wake, if he was surrounded now by splashing children who might have been hers.

  They neared the sharp folds in the ground that marked the entrance to the Neck. She could see the big pipes that carried water up from the lake. The pipes were clear, and she could see thick, greenish, rich fluid within. Food, taken away from people who needed it. A diffuse anger gathered.

  They walked into the Head.

  It was darker here. Most of the light came from the Stomach lake, a greenish glow at the mouth of this broad tunnel.

  There was little free water here, little food. But still she urged Sun Eyes on. ‘Just a bit more,’ she said.