“Okay, the Lamprey is giving me all green thingies. I see no red thingies. So I am activating it in three . . . two . . . one . . . now.” Dinah tapped the Deorbit button.

Most of the Lamprey—the entire box—jumped away, headed toward Earth, propelled by white plumes of solid rocket exhaust. After a couple of seconds the motors burned themselves out and the box continued to coast away, unreeling a wire behind it. This came to a stop a minute later, dangling half a kilometer below the X-37, and pulled taut by tidal force.

“We have positive current flow in the tether,” Dinah reported. “So it’s working.” The wire, sweeping through Earth’s magnetic field on its orbit, was picking up a weak electrical current, creating a force that would slow the X-37 down. The effect was slight, but within a few hours the X-37’s orbit would decay to the point where it no longer posed a danger to the Cloud Ark, and in days or weeks it would descend into the atmosphere and be annihilated.

Twenty minutes remained before the Flivver’s orbit would next cross Izzy’s. But the physical separation was only a few tens of kilometers and they were still “on swarm,” meaning that the Flivver’s computer was talking to the Cloud Ark network and searching parameter space for the safest and most efficient way to reintegrate with it and to dock. That, plus the Lamprey’s success in moving the X-37 out of the way, ought to have cleared up most of the red that had been maculating Parambulator displays at the time of their departure. But when Dinah and Ivy turned their attention back to those screens, they looked worse than before. It was not immediately clear why. Parambulator was a beautiful thing from the standpoint of mathematics and data visualization, but there were times when you just wanted to know what the hell was happening. You wanted a narrative.

A text came through on Ivy’s phone. It was from Markus. She read it out loud. “Approach using visual observation and manual control,” it said. “Warning: collision debris.”

“Already?!” Dinah exclaimed. It wasn’t a good start if they’d already suffered a bolide strike a couple of hours into the Hard Rain.

“It was fratricide,” Ivy said, still reading. “Looks like an arklet got cornered.”

Getting cornered was a problem that had arisen in simulations. The swarm as a whole would look for solutions that would prevent arklets from banging into each other with minimum expenditure of propellant. In a pinch, of course, it was okay to burn a lot of propellant to avoid a collision. But there were situations where a collision was going to happen no matter what, and there was nothing to do for it but choose the least damaging outcome. Getting cornered wasn’t supposed to happen; everything about Parambulator was supposed to prevent it. But the number of possible scenarios was infinite and nothing was ever certain.

“A controlled collision,” Ivy said, “no fatalities. But then some follow-on. Still being evaluated. There might be loose debris drifting around. That’s why he wants me to fly it in manually.”

“What kind of debris?” Dinah asked. “Hard stuff or—”

“Thermal protection, looks like,” Ivy said. “So that’s good.”

Apparently one of the modules, or an arklet, had lost some of the layers of reflective foil and insulation that were used to shield it from the heat of the sun. The stuff was feather light and so probably didn’t pose much of a threat to the Flivver. But it would look huge on radar and make Parambulator go crazy.

Ivy, in the pilot’s chair, was monopolizing the only window. Dinah didn’t like flying blind, so she pulled up the interface for the Flivver’s eyeball camera.

Julia began to make a weird repetitive noise, a sort of wet, gurgling drone.

She was snoring.

“Long day for her, I guess,” Ivy remarked.

“Yeah.” Dinah had no precedents to tell her how she should feel toward the ex-president at a time like this. On the one hand, her behavior had been reprehensible. On the other, she had, within the last few hours, lost her husband, her daughter, her country, and her job.

With a few moments’ panning around, Dinah was able to center Izzy in the camera’s frame, then zoom in. Izzy was on the night side of the Earth just now. In normal times—or what used to be normal—it would have been dark, but now she was lit up from below by the red glow of the atmosphere, punctuated from time to time by bluish flashes, like lightning strikes, as large bolides plowed into the air three hundred kilometers below. Of course, Dinah had never seen Izzy so illuminated, and it took a bit of getting used to.

From a distance Izzy looked fine, but at higher magnification Dinah began to see visual noise that gradually resolved into drifting bits of debris—the shredded thermal protection that Ivy had mentioned.

Izzy had become unfathomably complicated in the last two years. Dinah rarely saw it from a distance, so she didn’t have a strong sense of what was normal. But the more she zoomed in, the more certain she became that something weird had happened on the nadir side, near the junction of Zvezda and Zarya.

Complicated though she might be, Izzy was complicated in a way that was orderly, stiff, and stable. The one exception to that rule was Amalthea, but even that had become more regular as the Mining Colony’s robots had reshaped it. What Dinah was zooming in on now was messy, and it was unstable: big expanses of thermal shielding material that had been torn loose and were now stirring randomly in the nearly imperceptible wind. At a glance, it did not look like a serious matter. “Serious” would have meant a hull breach, air erupting from a hole, perhaps dragging debris, or even human bodies, along with it.

“I’m thinking maybe a grazing impact at most,” Dinah reported. “A near miss between an arklet, or something, and the nadir side of Zvezda. Destroyed some thermal shielding but caused little if any structural damage.”

“They are reporting zero serious casualties,” Ivy said. “Some bumps and sprains aboard an arklet. So maybe you’re right.”

“Maybe,” Dinah said. For they had now drawn close enough that the camera could provide more detail. What had been exposed by the damage to the thermal shielding looked unfamiliar to her at first glance: a big T-shaped construct that jutted out to the nadir side of the Stack like a pair of handlebars. It was studded with many long neat rows of small, identical objects, gleaming in the occasional flashes from below.

Finally it all snapped into place in her head: she was looking at Moira’s thing. The HGA, the Human Genetic Archive. Moira had given her a tour once, but that had been from the inside, or enclosed and pressurized part of it. Now Dinah was seeing the same thing from the outside. Until now, this had always been concealed from view by the thermal shielding. Once that was torn away, its internal structure could be seen: the rows and rows of hexagonal sample racks, each carrying its load of deep-frozen sperm, ova, or embryos, waiting in the near-absolute-zero cold and dark of space.

“How has Moira been doing with the dispersal project?” Dinah asked, forcing her voice to sound relaxed.

“Well . . . obviously, the schedule got compressed when we learned about the Eight Ball. Just like all of our other preparations did. But I guess my real answer is that I don’t know,” Ivy said.

Ymir

“. . . AND THEN THE FORCE OF THE VACUUM CAUGHT HOLD OF THE hatch, and to my horror I saw it slam shut right in front of me! I tried to pull it back open, but the suction was too strong. I cannot tell you, Markus, how helpless and guilty I felt when I realized that Dinah was trapped on the other side.”

Markus’s eyes went to Ivy. He had been listening to Julia for a long time, and needed a break.