Titan n-2

by Stephen Baxter

  She lifted up her boot. “It has a lot of cohesion. I’m leaving firm footprints here; the regolith seems to take a sharp slope, of seventy or eighty degrees. Cohesion and adhesion.”

  “Probably from organic deposits on the grain surfaces,” Rosenberg said.

  “It’s going to be easy to walk here,” she said. “Much easier than on the gumbo. I guess we can leave the snowshoes behind.”

  Angel was walking over to Benacerraf. Free of his harness, he seemed to bounce between each step; he floated over the ice like a human-shaped beach ball, she thought, his white suit still streaked with gumbo. He looked like a floating ghost, in the murky light.

  Benacerraf stared at her own footprints, crisp and sharp and white, in the virgin Titan ice.

  Benacerraf and Angel harnessed themselves up once more, and renewed their haul up the ice slope. The footing was much easier, and the aluminum carapaces of the sleds scraped easily over the crisp, firm ice.

  Soon their footprints stretched down the flank of the mountain behind them, partly obscured by the snail-like trails of the sleds.

  The whiteness of the ice underfoot was a sharp contrast to the grey-black lid of methane clouds. Through gaps in the clouds overhead she could see the upper haze layers, a uniform orange which seemed lurid to eyes which were becoming accustomed to the Earth-like grey-white of the ice. Again, she had the disorienting feeling that she was travelling through some false-color VR landscape; Angel’s suit looked underlit by the white below, the contours of his body shaded by the burnt orange above.

  Another couple of thousand feet higher, Benacerraf called a halt. She felt hot and cooped up in her suit. She felt as if she could just open up her faceplate, take a deep breath of this cool mountain air, and rub a little snow in her face.

  Angel slowed and stopped. Over the VHP link between them she could hear the rattle of his vacuum-damaged throat, the slurping of water from the nipple in his helmet. Discreetly, Benacerraf checked his suit diagnostics on her chest panel. He was using a lot of consumables, but no more than she was.

  “What do you think?” he said at length. “Is the regolith deep enough here?”

  “It’s hard to tell. It all feels the same underfoot.”

  “The depth is probably pretty uniform, away from the gumbo layer,” Rosenberg said from Tartarus. “It’s just, the higher you go, the cleaner it should get.”

  “This will do as well as anywhere,” Benacerraf said. “Come on, Bill. Let’s get these damn sleds filled up.”

  She bounded down the few paces to the side of her sled and lifted out her shovel.

  As it happened, the shovel was the same piece of equipment she’d used to bury Nicola Mott.

  Using both hands, holding the handle away from her body, she pushed the rounded edge of the shovel blade into the regolith. There was a hiss of metal against ice grains.

  The blade sank in easily for a few inches, but resistance built up quickly. When the blade was maybe five inches deep, she couldn’t push it any further in. She hopped forward and leaned over the crude handle of the shovel, propping it under her belly with her hands still wrapped around it, trying to use her weight to push the shovel deeper.

  She achieved maybe another inch of penetration. In this gravity, her weight didn’t count for a lot.

  She straightened up, panting, and lifted up the shovel. Some of the ice she’d raised so laboriously just floated off the blade.

  She swivelled to the sled, and dumped in the ice regolith. It fell slowly, and rattled as it hit the aluminum hull of the sled.

  She straightened up again. “It’s not going to be easy,” she said to Rosenberg, “When you push in the blade, the regolith compacts after a couple of inches. It feels more like sand than snow—”

  “It isn’t snow,” Rosenberg said.

  “Whatever. It’s going to take a long time to fill the sleds like this.”

  “Paula.” Bill Angel said. Try this.”

  She turned to look.

  He was bending, closer to the ground, so that his blade was entering the regolith almost parallel to the surface. “See?” he said. It slides easy into these looser top layers. Then you can scoop up a big shovelful. I can feel it.” He was right, she saw; he was managing to lift big, tottering heaps of the regolith, which he dumped into his sled.

  “I guess he’s right,” Rosenberg said. “You’re gathering raw materials for life support, Paula, not digging for a core sample. Get it whichever way is easiest.”

  She bent, and started scraping up the regolith the way Angel did it. The first couple of times she managed to come away with piles of loosely-packed regolith on her blade as big and precarious as Angel’s. But the constant bending and straightening, against the stiffness of her suit, began to tell on her lower back and thighs.

  She turned so that she was working uphill. That brought the regolith closer, and made it a little easier on her back, but it was still difficult, heavy work. Her EMU wasn’t made for heavy labor; it was hot, confining, uncomfortable, and she wished again she could take it off.

  She thought about Angel. Now he was humming, the same marching tune as before.

  Perhaps it was the climb. She felt vaguely exhilarated herself — liberated by the steady exercise, the sense of altitude, the crispness of the icy regolith.

  She realized now that she’d never truly gotten over her sense of confinement after being cooped up in Discovery for all those years; Titan, with its lousy visibility, socked-in clouds and gloopy, impeding surface, wasn’t much of a release.

  Maybe the same factors are working on Angel, she thought. Maybe this is working to clear out the contents of his head.

  All he needed, she supposed, was a little space.

  The light changed, subtly. It became somehow pearly.

  She lifted up her head.

  Raindrops were falling towards her face.

  It wasn’t like rain on Earth.

  It was methane rain.

  The biggest drops were blobs of liquid a half-inch across. They came down surrounded by a mist, of much smaller drops. The drops fell slowly, perhaps five or six feet in a second. It was more like being caught in a snowstorm, with the flakes replaced by these big globules of methane liquid. The drops weren’t spheres; they were visibly deformed into flat hockey-puck shapes, flattened out, she supposed, by air resistance. They caught the murky light, shimmering.

  The first drops hit her visor.

  Each drop impacted with a fat, liquid noise; their splash was slow and languid. The drops spread out rapidly, or else collapsed into many smaller, more compact droplets over the plexiglass. Low surface tension, she thought automatically. Some of the liquid trickled down the contours of her visor, but the evaporation of the drops, over such a large area, was rapid, and each drop dried quickly.

  Her face felt a little cooler, she guessed because of the evaporation of the liquid, carrying away some of her heat.

  She leaned forward, compensating for the mass of her pack, and looked down. As it hit the ground, each raindrop broke up into many smaller drops, which trickled rapidly into the regolith, rinsing the tholin streaks off the ice.

  Bill Angel turned his head this way and that, letting the rain fall over his faceplate and helmet. “It sounds beautiful,” he said. “Like being a kid again. Lying under a wooden roof at night, hearing the rain come down…”

  “Yes,” she said. “Yes.” And in that moment she felt doser to Angel than at any time since they left Earth.

  “You know,” Rosenberg said, “of all the worlds in the Solar System, only Earth and Titan know rain. I wish I was there.”

  “Next time, Rosenberg.”

  She stood in the rain, wishing it would go on forever. Not for the first time she was lulled into a kind of peace by the slowness of Titan, the paradoxical heaviness of time in this thin gravity, the slow rhythms of nature here; it was as if she was shedding the frantic, energy-laden pace of Earth, and becoming a creature of Saturn twilight.

 
At last, the slow patter of drops against her helmet stopped. She felt a sharp stab of regret.

  There was still a faint wash of small droplets around her, but these were dissipating quickly. And now there was a mist in the air, a light, yellowish fog; it made the air seem brighter, like the air after a storm on Earth. Angel, standing before her, looked as if he had some kind of halo around him.

  She reported all this to Rosenberg.

  “That’s a rain ghost, Paula. I want you to take a sample…”

  She dug a sample bottle out of a pocket on her EMU, and opened it to the air. “Why?”

  “The rain starts by nucleating around particles in the upper atmosphere. That stuff is usually suspended higher up, and won’t reach the surface. But it can be transported down by the weight of the rain, down to lower altitudes. When the rain stops, the last drops evaporate, leaving their cores exposed. The rain ghost. You see? Paula, what we have is a free sample of upper-altitude haze particles.”

  “Terrific.” She stoppered the bottle, labelled it with her propelling pencil (not a pen — ink froze), and put the bottle back in her pocket.

  She looked around. The rain had gone: evaporated from her visor, and was absorbed into the ground. Above them, the methane clouds, evidently rained out, had cleared to a scattered, broken layer of dark fragments, revealing an orange glow above.

  Save for the lingering rain ghost, it was as if the storm had never been.

  “I guess we can go back,” Benacerraf said. “The sleds are full.”

  “Yes,” Rosenberg said. “Your walk-back limit—”

  “Oh, fuck our walk-back limit,” Angel said abruptly. “Rosenberg, how far are we from the top of this mountain?”

  Rosenberg said reluctantly, “Give me an altitude.”

  Benacerraf consulted her altimeter. “Around eight thousand feet.”

  “That leaves you three thousand shy of the summit. I don’t recommend going further,” Rosenberg said strongly. “You’re climbing above the planetary boundary layer, and the winds are going to pick up. And in another thousand feet or so you’ll be in the methane cloud layer.”

  “Actually, that shouldn’t be a problem,” Benacerraf said slowly. “The cloud is pretty broken up after the rain, Rosenberg.”

  “I can’t believe I’m hearing this,” Rosenberg snapped. “Maybe the altitude’s affecting your oxygen supply.”

  “Come on, double-dome,” Angel said. “Don’t be an asshole.”

  “Bill—” Rosenberg hesitated. “What’s the point? You won’t be able to see anyhow. I’m sorry to be brutal, but—”

  “The point, dipshit, is that I’ll make it to the top. The point is, I haven’t crossed two billion miles just to stop a few thousand fucking feet shy of the highest point on the moon. Or isn’t that logical enough for you?”

  “Paula, if you go along with this, you’re as crazy as he is.”

  Anger flared in her. “Drop it, Rosenberg.”

  They were, she decided there and then, going to climb the mountain.

  For today, anyhow, Bill Angel was out of his craziness. And if anything was going to keep him together, this kind of experience was.

  Anyhow he was right. Wasn’t this exactly the kind of exploration they had come so far to make?

  She floated over to Angel. She took his hand. “Rosenberg, I’ll leave markers, and give you an altitude every few hundred feet.”

  “How can I stop you doing this?”

  “You can’t,” Angel said. “So shut the fuck up, and enjoy the ride.”

  Hand in hand, Benacerraf and Angel began to climb the icy regolith.

  With the methane clouds broken up, it was bright enough to walk without helmet lamps.

  Free of the gumbo, free of the sled, the landscape opening up around her, she felt as if she was floating above the surface. She felt the way Marcus White and some, of the others had described walking on the Moon. Only the stiffness of her surface suit, the disconcerting mass of her backpack, encumbered her now.

  It was like being eight years old again, she thought: her adult cares sloughed away, her body light and compact and the air fresh and new and full of light.

  Soon they were in the lower layers of the cloud. It was like being in a thick, dark mist, like smoke from a forest fire. Benacerraf could still see, roughly, where she was, but she was glad to have the slope of the ground for orientation.

  After a couple of hundred feet they emerged above the cloud layer, into clear orange air. The regolith here was still pretty much grey-white, cleansed by methane rain. The lighting was orange and grey, surreal, dim like an early dawn, but bright enough they didn’t need their helmet lamps to see.

  She strode on, into the light.

  They came upon the summit suddenly.

  The regolith slope foreshortened before Benacerraf, and she realized they were approaching some kind of ridge. She slowed, and pulled at Angel’s hand to warn him.

  Still hand in hand, they approached the ridge. The slope flattened out, to a broad ledge maybe twenty feet wide. Leaving Angel behind, Benacerraf walked cautiously forward.

  She was standing on the rim of a crater, puncturing the summit of Othrys.

  “Take it easy, Paula,” Rosenberg said. “We don’t know how friable that surface is. Don’t go close to the edge.”

  The crater was like a huge amphitheatre, bathed in the ubiquitous orange glow. “It must be four miles across, maybe five… I can see the far rim quite clearly. And in the base there is a dome structure. No central peak—”

  “It’s a caldera,” Rosenberg said. “A cryovolcano. Fuelled by ammonia-water lava, a remnant of the primeval ocean.”

  She looked down towards the ground.

  The light was bright — better than twilight up here, like an autumn sunset, perhaps. The sky was empty of cloud, save for a scattering of light cirrus clouds around the zenith, probably methane and nitrogen ice.

  The methane clouds formed a distinct layer, a thousand feet below her. They were black, fat cumuli with lumpy tops and flat bases, like froth riding on an invisible membrane in the air. The clouds stretched to the horizon, but through them she could make out the ground. It was an orange sheet, punctured by the jet black of ethane crater lakes, like a photographic negative of the Everglades. She thought she could make out Clear Lake, its compact cashew-nut shape far below, all but hidden by cloud and mist.

  The horizon was visible, even through the orange haze. It was the dark band where the parallel sheets of sky-haze, methane cloud layer and punctured land met, all around her. It seemed close by: seventy or eighty miles away, she judged. And it was curved, quite sharply, as if seen through a distorting lens.

  Titan was visibly round; she had a powerful sense that she was standing on a sphere, that she was clinging to the surface of a small, three-dimensional object, suspended in space, swathed by a duck layer of air.

  “Paula.” Angel was waiting for her, a few yards short of the summit. “Are we here?”

  “Yes, Bill. We made it. We climbed Othrys.”

  He was standing slumped forward to balance his pack, and with his arms held loose at his sides. It was like an ape’s gait, she thought.

  And so they were: two clever apes, who had made it to the highest point on Titan.

  She walked down, took Angel’s hand, and began to lead him to the summit. “It’s beautiful, Bill, so beautiful.”

  His blind face turned, the orange curve of Titan reflected in his visor. The crunch of the regolith beneath his boots was loud and sharp in the still, huge air.

  When they got back to Tartarus, Rosenberg insisted on passing the Titan water through the life support system’s filters to get rid of the remnant tholins. At last, though, he was able to bring Benacerraf a bowl — in fact an EMU visor — brimming full of cool, clear Titan water.

  She raised it to her lips.

  It was the finest drink she’d taken in seven years, sweeter than wine.

  * * *

  Jiang Ling fir
st saw the asteroid with her naked eyes when Tianming was ninety days out from Earth, ten days from its closest encounter.

  At first the asteroid was barely more than a point of light — indistinguishable from the remote stars, had she not known where, precisely, to look. But by the day after that 2002OA had grown to a distinct oval shape: almost like a potato, she thought irreverently, battered and irregular. She knew that from now on the asteroid would grow visibly, day by day, and then hour by hour, until at last its battered grey hide filled the small viewing window of her living compartment.

  After the closest approach, the asteroid would then recede, just as rapidly.

  But that, for her, was only a theoretical possibility.

  Every day she performed two softscreen shows: one in Han Chinese for the benefit of her countrymen, one in English for the foreigners. She was allowed to say what she wished, although the Party expressed clear, if rather obvious, preferences.

  Jiang adjusted the angle of her big S-band antenna, ensuring it was centered on the fat disc of Earth. Then she positioned herself before the Tianming’s single camera, fixed to a bracket on the wall. She had no props or charts or effects; none were necessary. It was sufficient that she simply talk into the camera, smoothly and plausibly, and production crews on the ground would later patch in such illustrations and other footage as was required.

  She anchored herself over her table, and prepared what she would say.

  …In the ninety days since it had been pushed out of orbit by its solid-propellant injection engine, Tianming had coasted slowly away from Earth, heading outwards from the sun. It had dogged the heels of the home planet, she thought, as a dog will track its owner. Thus she had drifted more than three and a half million miles from Earth, and when the Tianming’s slow thermal roll brought the small viewing window into the right direction, she could see Earth and Moon together: twin crescents before the huge glare of the sun, the smaller brown alongside the fatter blue-white, so close to each other she could cover up both Earth and its satellite with the palm of her right hand, upheld before her.