“I had heard you’d come up,” Moira said, “but it didn’t quite register, as I’ve been awfully preoccupied.”

“I can only imagine,” Doob said. “While I’ve been running around shilling for the Cloud Ark, you’ve probably been doing actual science, huh?”

“Getting ready to do it might be more precise,” she said. Her big brown eyes, behind a geeky but stylish pair of glasses, strayed in a direction. “Is that what they call forward?” she asked.

“Yes.”

“Well, the place where I’m working is about as far forward as it’s possible to get, because they want my lab to be sheltered by the big rock.”

“Amalthea.”

“Yes. And if we go there, I can show you a bit of what I’ve been up to. I feel I should offer you tea as well, but I don’t know how to make it here.”

Doob smiled at her way of talking. She had been a fiend for theater at Oxford, and might have become an actress. Intensely conscious of the difference between the way her people in London talked and the way people talked at her school and at Oxford, she’d become good at switching between those accents for effect. “I’d be happy to have a look,” he said. “I think I know the module you’re talking about—I saw it docking a few days ago, and was curious.”

HE HOOKED THE UNOCCUPIED PRESSURE SUIT TO THE WALL OF MOIRA’S lab and it hung there, an inanimate observer, as Moira showed him around. Never one for the life sciences, Doob couldn’t understand everything she was saying to him, but he didn’t care. Being able to relax and let someone else explain science to him was a welcome turnabout.

“Do you know about the black-footed ferret?” she asked.

“No,” Doob said. “I think you can pretty much assume that my answer to all questions about biology and genetics is going to be in the negative.”

“Ninety percent of their diet was prairie dogs. Farmers killed almost all of the prairie dogs and so the population of black-footed ferrets crashed to the point where only seven remained. From that breeding stock, it was necessary to bring them back.”

“Wow, only seven . . . so inbreeding must have been an issue?”

“We speak of heterozygosity,” she said, “which just means the amount of genetic diversity within a species. In general, it’s a good thing. If you have too little of it, then you start to see the sorts of problems that we associate with inbreeding.”

“But if the breeding stock is reduced to only seven . . . then that’s all you have to work with, right?”

“Not quite. Well, technically yes, I suppose. But by manipulating some of the genes, we can create heterozygosity artificially. As well as getting rid of some of the genetic defects that would otherwise propagate through the whole population.”

“Anyway,” Doob said, “it’s obviously of interest to us now.”

“If the Cloud Ark’s as populous as they claim it’s going to be, and if people come up with frozen sperm samples and ova and embryos and all of that, then the human population is probably all right. We’ll have enough heterozygosity to make a go of it. My work here is going to be more concerned with nonhuman populations.”

“Meaning . . .”

“Well, you’ve probably heard that we’ll be growing algae as a way to generate oxygen. Which is only the start of a simple ecosystem that will have to be developed and grown, and become much less simple, over the years to come. Many of the plants and microorganisms that will make up that ecosystem will be cultivated from initially small breeding populations. We don’t want to have a repeat of the Irish potato famine, or something analogous, with the plants we rely on to make it possible to breathe.”

“So your job will be to do with them what was done in the case of black-footed ferrets.”

“Part of my job, yes.”

“What’s the other part?”

“Being a sort of Victorian museum curator. Did you ever visit Clarence’s home in Cambridge?”

“No, I’m sorry to say. But I heard his collection was magnificent.”

“It was crammed with all of these stuffed birds and boxed beetles and mounted heads of beasts, gathered by Victorian gentleman-collector types in pith helmets, doing their bit for science on the fringes of the empire. Not scientists as we’d define them today but contributors to the scientific ideal. These things overflowed the museums and Clarence acquired them by the lorry-load, especially after Edwina died and couldn’t forbid it. Anyway, I’m that person now, except that the samples are all digital, and they are all on these things.” She tapped a thumb drive that was floating around her neck on a chain. “Or their rad-hard equivalents.” She pronounced the technical term with a dubious and ironic tone of voice, suggesting that she and the International Space Station would take a while getting used to each other. “You know the general story—I’ve heard you talking about it on YouTube.” She switched into a credible imitation of Doob’s flat midwestern vowels: “‘We can’t send blue whales and sequoias up on the Cloud Ark. And even if we could, we couldn’t keep them alive there. But we can send their DNA, encoded as strings of ones and zeroes.’”

“You’re going to put me out of a job,” Doob said.

“Good. Then I’ll put you to work here,” Moira said. “This is labor intensive as hell, and they’re not sending me enough help.”

“I thought it was all automatic.”

“If the Agent had given us another couple of decades to improve our gene synthesis technology, it might have become so,” Moira said. “As it is, we’ve been caught in a bit of a gawky adolescent phase. Yes, we can take one of these files”—she tapped the thumb drive around her neck—“and we can create a strand of DNA from it, beginning with a few simple precursor chemicals. But the amount of human intervention is still ridiculous.”

“I’m guessing that is some pretty high-level human intervention too.”

“My Jamaican grandfather worked in the engine room of a navy ship,” Moira said, “which is how our family ended up in England. When I was a little girl, he took me on a tour of one of those ships, and we went down into the engine room, and I saw it, the engine, with all of the bits exposed; the bloody thing was naked and men had to go crawling around on it with oil cans, lubricating the bearings by hand and so on. That’s a bit like where we are now with synthesizing whole genomes.”

“But for now,” Doob said, “that’s far in the future, right?”

“Yes, thank God.”

“For now you’re going to be tinkering with intact organisms.”

“Yes. Just so. Still quite difficult, but I think manageable.” She looked around. The module in which they floated looked nothing like a lab. Everything was sealed up in plastic or aluminum cases, taped shut and labeled with yellow sticky notes. “Sorry,” she said. “Underwhelming. Hardly worth the trip, is it?”

“How can I help?”

“Get me some fucking gravity,” Moira said. Then she laughed. “Can you imagine trying to do tricks with liquids in zero gee? Because that’s all a lab is.”

“It must look frustrating to you now,” Doob said. “Everything in boxes, no gravity to make it all work.”

“I know, I know,” she said. “I’m whingeing. They’ll put this thing on a bolo, won’t they?”

“Maybe a third torus. Big enough to make something close to Earth-normal gravity. Lots of space to work in. A staff of eager Arkers.”

“That’s your job now, isn’t it?” Moira said. “Cheerleader for the Ark.”

“It was my ticket up here,” Doob said. He could feel a little warmth creeping into his face, and cautioned himself not to say anything he was going to regret. “We all needed that ticket. Now that we have paid the price of admission, we need to make it work.”

Moira, perhaps sensing she’d gone a little too far, kept her silence and would not meet his gaze.

“And as of today,” he said, “we have one year.”