Ark

by Stephen Baxter

  ′More mountains up ahead,′ Wilson muttered, eyes fixed, the flaws in his stubbly flesh picked out by the glow of the low sun.

  The approaching mountains were a multiple sawtooth chain, dead ahead, a geological system hundreds of kilometres deep. They were silhouetted from Helen′s point of view. She compared the view with the animated map on the console, which showed a dotted red line and a cartoon shuttle swooping over a jagged mass. ′They′re right where they should be, Wilson.′

  ′Good. And so are we. In which case we should come on our landing site soon.′

  The mountains swept beneath their prow. Their flanks were gouged by glaciers, ice glowing pink-white on the rock. The parallel ranges fell away, dissolving into foothills, themselves young and sharp-edged. Now ahead of them lay a plain, barren and strewn with rock, with a sheet of ice beyond it, the surface of a frozen lake. The shuttle dipped sharply, heading for the lake, its destination obvious.

  ′Right on the nose,′ Wilson said. ′That lake′s the nearest thing to a natural landing strip we spotted. I hope everybody′s still strapped in.′

  Helen glanced over her shoulder. The low sun shone straight into the cabin, bathing the children′s faces with its eerie pinkish light - eerie now, but maybe in a couple of years they′d get used to it. The children sat slumped in the gravity, though they mostly seemed awake. Some were crying, and others looked as if they had soiled themselves, or been sick. Helen forced a smile. ′Not long now. Just hold on—′

  The shuttle dropped sharply. She gasped, fearing she was falling.

  ′Sorry,′ Wilson muttered. ′Air pocket. This damn air is just as thick as we thought, but lumpier, more turbulent. A real stew. Here we go, initiating final descent sequence.′ He tapped a switch, and gripped his controls hard. Now he and the autopilot were sharing the flying of the shuttle between them, though Wilson always had the casting vote.

  There was a clatter from beneath her feet, and a roar of air.

  Alarmed, she asked, ′What the hell′s that? Has a pump broken?′

  Wilson just laughed, without taking his eyes off the scene outside the window. ′The landing gear just dropped. And that′s no busted pump, that′s the wind, baby. Here we go. Coming down fast now …′ He fell silent, watching the fleeing landscape, tracking monitors that showed his speed and altitude and rate of descent. The shuttle shuddered again as its aerosurfaces bit into the thick air.

  They passed a last chain of hills. They were already beneath the summits of the highest of them, Helen saw. Then the shoreline of the frozen lake fled beneath their prow, its edge marked by parallel bands in the ice, as if the lake had melted and refrozen repeatedly. Evidence of volcano summers; every so often, Venus had advised her, a big enough eruption would inject so much carbon dioxide into the air that the temperature globally would climb, maybe for years. She wished Venus were here, talking her through this, holding her hand.

  The shuttle shook again and dropped some more. Now they were flying very low over the lake. In the light of the sun Helen could see detail, rocks and scraps of ice scattered over the surface, fleeing beneath the prow.

  Wilson muttered, ′Nothing′s ever so smooth as it looks from space. As long as we miss those itty bitty rocks with our skids, we′ll be fine. Coming down easy now. A hundred metres up. Eighty. Sixty. Woah—′ He hauled on the translational control and the shuttle banked sharply right. Helen saw a field of ice boulders that had been right in their path. When he had the shuttle pointed towards a clearer track, Wilson released the control, and let the automated systems level the bird up again. ′That was close.′

  Helen pointed dead ahead. ′We′re kind of near the shore.′ Beyond which more hilly ground rose up, looking rough and rock-strewn, and mottled with that strange black colour.

  Wilson grinned. ′Maybe, but we only get one pass at this, girl. Let′s hope we got enough room.′ A monitor chimed; the radar altimeter showed they were only ten metres up. ′Here we go …′ He pressed the handle forward gently. The lake lifted up to meet them.

  The skids hit the ice. The shuttle rattled and skipped back up into the air, and Helen clung on to her couch. The shuttle dropped again, and bounced, and then she heard a squeal of metal as the skids scraped along the ice sheet. There was another bang, and Helen was thrown forward against her restraints, as if some great hand had grabbed the rear of the craft.

  ′Chutes deployed!′ Wilson called. ′Wow, what a ride this is.′

  With the parachutes dragging at the thick air, the shuttle soon slowed. The last few metres, as the skids bumped over every rock and ice block in their path, were jarring. Then the shuttle swivelled through a few degrees, and slid sideways for another dozen metres, before coming to a halt.

  Wilson punched a button. ′Chutes jettisoned. First job is to collect the silk, we′re going to need it later …′ He looked stunned. He tapped his microphone. ′Halivah, shuttle B. We′re down, down in one piece. Yeah! We′re down,′ he repeated more quietly, and he looked over at Helen. ′Now what?′

  98

  The shuttle′s exit ramp was simple, a section of the hull that would fold down to the ground, lined with a corrugated surface for traction.

  Helen, Jeb and Wilson stood by the closed door. They wore thick-lined bright green overcoats, and gloves and hats, and face masks connected to filter bottles. A few of the older children were with them, all in coats and masks, while the rest waited in the main cabin. Jeb, awkward and panting, was carrying little Sapphire Murphy Baker in his arms. The girl′s face was almost entirely hidden by her mask. They were all hanging on to rails, supporting their unaccustomed weight. Jeb and Wilson had at least grown up in Earth gravity; Helen had only known the hull′s fractional gravity and that not for thirty years since the Split, and the one and a quarter G felt crushingly heavy. But she stood, determined.

  ′So,′ Wilson said, his voice muffled by his mask. ′Everybody set?′

  ′Do it,′ Helen murmured.

  Wilson pulled a lever. With a hiss of hydraulics the hatch gracefully yawned down to the ground. Cold, sharp air washed into the shuttle, and a pale pink light drowned out the glow of the artificial lamps.

  Wilson glanced around. ′Nobody dead yet? Ready for the EVA?′

  Helen snorted. ′An EVA which is never going to end, Wilson.′

  ′I guess not.′ He led the way out of the hatch.

  They all walked cautiously down the ramp - cautiously as they encountered the new world, and cautiously because Helen wasn′t sure she even remembered how to walk. Jeb carried little Sapphire, who looked around wide-eyed.

  They were looking straight towards the sun, which hung huge in a pink-brown sky. It was maybe forty times as wide as the sun′s disc as seen from Earth, but you could look directly at its pale glow without blinking. The hills at the edge of the lake rose up, coated with streaks of black, their shadowed faces thick with frost. Shapes like stocky trees, squat and dark, pushed up from the hills′ flanks.

  Helen felt a deep, gut-wrenching fear to be walking out of the shelter of the shuttle like this, to enter openness, infinity, to be for the first time in her whole life not contained within a hull. This was not like the HeadSpace sims, she thought; in the end they had been no real preparation. And yet she kept walking, one foot in front of the other, down the ramp after Wilson. She was evolved for this, she told herself. The kids were young; they would adapt.

  They paused before they got to the base of the ramp.

  ′I think I see open water over there,′ Jeb said, pointing. ′See, in the valley between those hills? Like a river, feeding the lake.′

  ′I can′t see,′ Helen said. She had trouble focusing on the middle distance. But then she′d only ever had to look at things within the hull, or at infinity, nothing in between. Maybe her eyes would adjust.

  ′We can always move closer to the subsolar point if we want,′ Wilson said. ′The shuttle is designed to break down to build habitats, sleds. We might try to get to the ocean. It′s no
t far, fifty klicks.′

  Helen, new to planets, didn′t want to sound foolish. ′You think those tall things are trees?′

  ′If they are, their leaves are jet black,′ Jeb said. ′And so′s that grassy stuff at their feet.′

  ′Well, that makes sense,′ Helen said. ′The M-sun′s light isn′t like Earth′s. It peaks in the infra-red. Photosynthesis here needs to be efficient, absorbing as much of the spectrum as it can consume. Hence it looks black.′

  Jeb the farmer′s son asked, ′So you think we really can grow crops here? It′s all so strange.′

  ′Hell, yes,′ said Wilson, and he waved a gloved hand. ′In the long term there are all sorts of advantages to a world like this. That sun′s never going to move from where it is in the sky.′

  ′It′s always morning here,′ Helen murmured.

  ′Always morning. We can set up mirrors to concentrate the light. Later, when we get back off planet, we can throw up strings of orbital mirrors to focus the light on our farms, even start lighting up the far side and melt that damn ice cap.′

  Helen smiled behind her mask. ′One step at a time, Wilson.′

  ′I think I smell sulphur,′ Jeb said.

  ′Volcano air,′ Wilson said.

  Helen took another step, towards the base of the ramp. It had cut a shallow groove in the ice, which was gritty and littered with small rocks and a thin ash, maybe from some volcanic event.

  On impulse Jeb kneeled down, cautiously, and set little Sapphire down on the ramp. Sapphire, the youngest of the crew, too young to know she had not yet learned to walk, tried to stand up, and fell flat on her backside. But she just rolled over and got up on her hands and knees and began to crawl, a bit unsteadily, but purposefully.

  And she crawled right off the edge of the ramp and onto the ice of Earth III. She squealed at the cold, and then poked her gloved finger into the groove the ramp had made. Helen felt regret, a deep, visceral stab, that her own children couldn′t come running down this ramp and join her.

  ′Look up,′ Wilson said.

  Helen straightened up. There, crossing the tall red sky, was a star, ruby-bright, tracking steadily towards the M-sun. It was Halivah, the only moon of Earth III. And as Helen watched, straining her eyes, the sky puckered, and the Ark was gone.

  Afterword

  In recent decades our understanding of how an interstellar voyage might be achieved, and of the possible destinations of such a voyage, has been transformed. See for instance Interstellar Travel and Multi-Generation Spaceships ed. Yoji Kondo (Apogee Books, 2003). This includes a new study on the size of viable human populations. A recent review of possible interstellar travel technologies is Centauri Dreams by Paul Gilster (Copernicus Books, 2004).

  The science and technology of the ′warp drive′, deriving from the seminal paper by Miguel Alcubierre (Classical and Quantum Gravity, vol. 11, L73-L77, 1994), is being developed by a community of researchers who came together for a seminar which I attended at the British Interplanetary Society on 15 November 2007, and which is documented in The Journal of the British Interplanetary Society, vol. 61 no. 9, September 2008. The journal contains a paper by Obousy et al. (pp. 364-69) outlining the notion of manipulating higher dimensions in order to inflate spacetime. The idea of reducing the energy required by shrinking the ′warp bubble′ is extrapolated from a paper by C. Van Den Broeck (Classical and Quantum Gravity, vol. 16, pp. 3973-9, 1999). For references on the optical effects of a warp field see a paper by C. Clark et al. (Classical and Quantum Gravity, vol. 16, pp. 3965-72, 1999) and a dissertation by D. Weiskopf (′The Visualisation of Four-dimensional Spacetimes′, University of Tubingen, 2001). The theoretical and engineering obstacles to creating a warp-drive starship remain huge, however.

  The astonishing Cold War dream of interplanetary travel powered by nuclear weapons is documented in George Dyson′s Project Orion (Holt, 2002). Revolutionary designs for high-energy ′plasma accelerators′ are being considered by the US Department of Energy (see New Scientist, 3 January 2009).

  The portrayal here of the prospects for intelligent life in the universe is drawn in part from my participation at the ′Sound of Silence′ workshop hosted by Arizona State University in February 2008, and the IAA Symposium on ′Searching for Life Signatures′, September 2008, in Paris. A recent review of ′exoplanets′, the newly discovered worlds of other stars, is The New Worlds by Casoli and Encrenaz (Springer-Praxis, 2007). The argument that most stars in the Galaxy that harbour complex life will be older than the sun was developed by Lineweaver et al. (Icarus, vol. 151, pp. 307-13, 2001). The ′starshade′ telescope concept was devised by Cash (Nature, vol. 442, pp. 51-3, 2006).

  The dynamics of extraterrestrial human societies is explored in, for example, Charles Cockell′s ′An Essay on Extraterrestrial Liberty′ (Journal of the British Interplanetary Society, vol. 61, pp. 255-75, 2008).

  The biblical quotations are from the King James Bible.

  Any errors or inaccuracies are my sole responsibility.

  Stephen Baxter Northumberland April 2009