Space

the huge world swim past her, it was as if she were flying through some cold, dark, gigantic cathedral.

And there was Triton, already bright and growing brighter, a pink-white pearl floating in emptiness.

The final approach to Triton was a challenge for the navigation routines. Triton, uniquely among the Solar System’s larger moons, orbited Neptune in a retrograde manner, opposite to the spin of Neptune itself. And Triton’s orbit was severely pitched up, some twenty degrees out of the plane of the ecliptic. It was thought these eccentricities of Triton were a relic of its peculiar origin: It had once been an independent body, like Pluto, but had been captured by Neptune, perhaps by impact with another moon or by grazing Neptune’s atmosphere, a catastrophic event that had resulted in global melting before the moon had learned to endure its entrapment.

Gurrutu entered a looping elliptical orbit. Madeleine watched as a surface of crumpled, pink-streaked water ice rolled beneath the craft. Triton’s misty twilight was marked by a single, yellow, man-made beacon: at the site of Kasyapa Township, home to Ben Roach’s people. They were not alone in Triton orbit. Many emigrant transport ships, of the same design as Gurrutu, still circled here. Others had been driven into the surface, to be broken up for raw materials.

After a day, a small shuttle came up to meet them. Triton’s atmosphere, a wisp of nitrogen laced with hydrocarbons, was too thin to support any kind of aircraft; so the shuttle would descend from orbit standing on its rockets, as Apollo astronauts had once landed on the Moon.

As the lander swiveled, the icy ground opened out before her. It was white, laced with pink and, here and there, darker streaks, like wind-blown dust. It was crowded with detail, she saw, with ridges and clefts and pits in the ice, as if the skin of the planet had shriveled in some impossible heat.

The lander tipped up and fell sharply, entering the last phase of its descent routine. The horizon flattened out quickly, and detail exploded at her. She was descending into a region crisscrossed by shallow ridges, a parquetry of planes and pits in the ice. But there was evidence of human activity: two long straight furrows cut across the random geologic features, a pair of roadways as straight as any Roman road, neatly melted into the ice. And at their terminus, set at the center of one of the walled ice pits, she saw a small octagonal pad of what looked like concrete, a cluster of silvery tanks and other buildings nearby.

The final landing was gentle. Madeleine and Ben suited up and climbed out of the lander.

The plain around them was still, the fuel tanks and crude surface buildings pale and silent. Under her boots there was a crunch of frost overlaying a harder, whiter rock.

Not rock, she told herself. This was ice, water ice. She scraped at the ice with her boot. It was impenetrable, unyielding, and she failed to mark its surface; it was like a hard, compacted stone. Here, in the intense cold, ice played the part of silicate rocks on Earth. There was an elusive pink stain about the ice, almost too faint to see. Some kind of sunlight-processed organics, perhaps.

She took a step forward, two. She floated and hopped, moonwalk-style. In fact, she knew, Triton’s gravity was little more than half the strength of the Moon’s. But she was a big clumsy human with a poor gravity sense; to her body, Triton and Moon were both lumped together in a catch-all category called “weak gravity.”

She looked up, into a black sky. There was no sense of air above her, no scattering of the sunlight: only a deep, starry sky, as if seen from the high desert — but with a dominant bright pinprick at the center of it. The Sun was bright enough to cast shadows, but it was not like authentic sunlight, she thought, more like illumination by a very bright planet, like Venus. The land was a plain of pale white, delicate, a land of midnight stillness, its planes and folds seeming gauzy in the thin light. It seemed a creation of smoke or mist, not of rock-solid ice.

Now she tipped back and peered overhead, where Neptune hung in the sky. The planet appeared as large as fifteen of Earth’s full Moons, strung across the sky together. It was half-full, gaunt, almost spectral.

From the corner of her eye she saw movement: flakes of pure white, sparsely descending around her.

“Snow, on Triton?”

“I think it’s nitrogen,” Ben said.

Madeleine tried to catch a flake of nitrogen snow on her glove. She wondered how the crystals would differ from the water-ice snow of Earth. But the flakes were too elusive, too sparse, and they were soon gone.

Ben tapped her shoulder and pointed to another corner of the sky, closer to the horizon. There was what looked like a star, perhaps surrounded by a diffuse disc of light.

It was a Gaijin engineering convoy: alien ships, built of asteroid rock and ice, en route to Triton.

The refugee Yolgnu had established their home in the rim wall of a shallow, circular depression called Kasyapa Cavus. This was on the eastern edge of Bubembe Regio, a region of so-called cantaloupe terrain, the complex, parquetlike landscape of the type Madeleine had noticed during the landing. The Cavus had a smooth, bowl-like floor, easy to traverse. There were tractors here, whose big, gauzy, balloon tires seemed to have made no impression on the icy ground. Kasyapa Township was a system of branching caverns. The colonists had burrowed far into the ice-rock, ensuring that a thick layer of ice and spacecraft-hull metal shielded them from the radiation flux of Neptune’s magnetosphere and from the relic cosmic radiation of deep space.

She was given a cabin, a crude cube dug into the ice. She moved her few personal belongings — book chips, a few clothes, virtuals of an X-ray burster and a black-hole accretion ring — into the cabin. Her things looked dowdy and old, out of place. The wall surface — Triton ice sealed and insulated by a clear plastic — was smooth and hard under Madeleine’s hand. After the cool spaces of the Neptune system, she found Kasyapa immediately claustrophobic.

Ben Roach was swallowed up by the family he had left behind, two whole new generations of nephews and nieces and grand-nephews and grand-nieces.

And here, of course, was Lena Roach. She had become a small, precise woman whose silences suggested great depths. She hadn’t seen her husband, Ben, for a hundred of her years, for most of her long life. But she had waited for him, built a home in the most unforgiving of environments.

It was immediately clear she still loved Ben, and he lovedher, despite the gulfs of time that separated them. Madeleine watched their calm, deep reunion with awe and envy. It was like grandmother greeting grandson, like wife meeting husband, complex, multilayered.

She explored fitfully, moodily.

It was obvious to her that the colony was failing.

The people were thin, their skins pale. Malnourished, they were specters in the dim sunlight. People moved slowly, despite the welcoming gentleness of the gravity. Energy was something to be conserved. There was an atmosphere of a prison here. These had once been people of openness, of the endless desert, she reminded herself. Now they were confined here, inside this icy warren. She thought that must be hurting them, perhaps on a level they didn’t appreciate themselves.

There were few children.

The people of Kasyapa were welcoming, but she found they were locked into tight family groups. She would always be an outsider here.

Madeleine spent a lot of time alone, cooped up in her ice-walled box. She engaged in peculiar time-delayed conversations with Nemoto; with a minimum of ten hours between comment and reply, it was more like receiving mail. Still, they spoke. And gradually Nemoto revealed the deeper purpose she had concocted for Madeleine.

“These people are starving,” Nemoto whispered. “And yet they are sitting on a frozen ocean…”

Triton was, Nemoto told her, probably the Solar System’s most remote significant and accessible cache of water, within the Kuiper Belt anyhow. She said that Robert Goddard, the American rocketry pioneer, had proposed — in a paper called “The Last Migration” — that Triton could be used as an outfitting and launching post for interstellar expeditions. “That was in 1927,” Nemoto said.

“Goddard was a farsighted guy,” Madeleine murmured.

“…Even if he got it wrong,” Nemoto was saying — had said, ten hours earlier. “Even if, as it turns out, Triton will be used as a staging post for expeditions from the stars. And not used by us, but by ETs. The Gaijin.”

But the ocean under Madeleine’s feet, tens of kilometers thick, was useless for the colonists as long as it was frozen hard as rock.

“Imagine if we could melt that ocean,” Nemoto said, her face an expressionless mask.

But how? The Sun was too remote. Of course the sunlight could be collected, by mirrors or lenses. But how big would such a mirror have to be? Thousands of kilometers wide, more? Such a project seemed absurd.

“It’s not the way humans work,” Madeleine said gloomily. “Look at the colonists here, burrowing like ants. We’re small and weak. We have to take the worlds as they are given to us, not rebuild them.”

Nemoto’s reply came many hours later. “And yet, that is exactly what we must do if we are to prevail. We are going to have to act more like Gaijin than humans.”

Nemoto had a plan. It involved diverting a moon called Nereid, slamming it into Triton.

Madeleine was immediately outraged. This was arrogance indeed.

But she let Nemoto’s data finish downloading.

It was a remarkable, bold scheme. The rocket engines that had brought the colonists here would now be used to divert a moon. The numbers added up. It could be done, Madeleine realized reluctantly. It would take a year, no more.

It was also, Madeleine thought, quite insane. She pictured Nemoto, stranded centuries out of her time, isolated, skulking in corners of the Moon, concocting mad schemes to hurl outer-planet moons back and forth, an old woman fighting the alien invasion, single-handed.

And yet, and yet…

She looked inward. What is it I want?

All her family, the people she had grown up with, were lost in the past, on a frozen world. She was rootless. And yet she had no pull to join this tight community, had felt no envy of Ben when Lena had recaptured him, on his arrival here. Her life had become a series of episodes, as she’d drifted through scenes of a more-or-less incomprehensible history. Was it even possible to sustain a consistent motivation — to find something to want?

Yes, she realized. It isn’t necessary to be picaresque. Look at Nemoto. She still knows what she wants, the same as she always did, after all these years. Maybe the same applied to Reid Malenfant, wherever he was. And maybe that was why Madeleine was attracted to Nemoto’s projects — not for the worth of the work, but for Nemoto’s singular strength of mind.

She went to discuss it with Ben. His first reaction was like hers.

“What you’re proposing is barbaric,” Ben said. “You talk of smashing one moon into another. You will destroy both.”

“It’s technically feasible. Nemoto’s numbers prove that a deflection of Nereid by the thruster systems from the orbiting transports would—”

“I’m not talking about feasibility. Many things are feasible. That doesn’t make them right. Once Triton is changed, it is changed forever. Who knows what future, wiser generations might have made of these resources we expend so carelessly?”

“But the Gaijin are on their way now.”

“We wreck this world, or they do. Is that the choice you offer?”

“Triton is ours to wreck, not theirs!”

He considered. “I will concede your plan has one positive outcome,” he said at length.

“What?”

“We are barely surviving here. The Yolgnu. That much is obvious. Perhaps with what you intend—”

She nodded. “It will work, Ben.”