Markus could be pretty unceremonious about things, which was just his leadership style—his way of implicitly telling people he expected them to do their bloody jobs without pep talks beforehand or congratulations afterward. It didn’t work for everyone. Some people liked ceremony. But he hadn’t invited any of those along on this expedition. So there was no particular moment when it all started. They just kept getting closer to the Earth. Slava darted up the companionway to the top of the command module, and a minute later announced that he was positioned before the controls of New Caird. Jiro called out milestones in the startup of the reactor, occasionally proffering hints as to how the figures should be understood: “That is a little faster than I expected . . . settling down now . . . this is according to plan . . . ready to proceed on your command . . .” and so on. Markus’s participation consisted largely of chewing his thumbnail while staring fixedly at his screen. From time to time he would reach out and type something, or swipe and tap on his tablet. Dinah’s work was almost entirely abstract, several layers removed from what obviously mattered. She tried to focus on it and to ignore the sounds of a thousand loose objects settling to the “floor” of Ymir as gravity “came on” due to a combination of Ymir’s increasing thrust and the steady buildup of atmospheric pushback.
“Now,” Markus said.
“Acknowledged,” Jiro responded. “Control blades are responding to program . . . and . . . we have criticality.”
Four gigawatts of thermal power—enough to supply Las Vegas—came online in the next few seconds. Dinah felt it as a massive increase in weight and heard it as a cacophony of creaks, groans, and crashing noises as the command module, and the ice surrounding it, came under structural load. She saw it on her screens as sudden and frantic change in windows that had remained frustratingly static for the last hours. The ice hoppers, which had been brimful for weeks, began to empty at a shocking pace as the augers spun. A couple of her “point of view” robots fell or skidded from their points of anchorage, events that showed up as sudden and unhelpful shifts in camera angle. She hit “go” on a program that tasked every robot in the shard to deliver more ice into the hoppers as fast as possible, and tried to keep one eye on that while monitoring the structural integrity of the shard as a whole. In the traditional scheme of things, miners had done all their work under gravity, so structural mistakes had manifested themselves soon, and dramatically, as cave-ins. Ymir was a mine that had been slowly delved under zero gee and only subjected to “gravity” for short periods when the engine came on, and so there was a certain nervous feeling of not knowing whether it might all collapse. So far, it looked fine.
“We are losing velocity nicely,” Markus muttered through what was left of his thumbnail, and Dinah permitted herself a glance at the graphs to verify that this was so. Time had gone by faster than she had known; they were just minutes away from perigee. “Nicely” in Markus’s phrasing meant “enough to make a difference but not so much as to kill us.”
Then Markus said, “Slava. A three-second burn, please.”
“Da,” answered the Russian. Then, a few seconds later, he said, “It is beginning.”
They wouldn’t have known Slava was doing anything, save for an external camera that Dinah had positioned on the surface of the shard at some distance from New Caird, looking back at it. This showed a ghostly blue flare emerging from the small ship’s nozzle bell, shoving Ymir’s nose down and swinging its stern up slightly.
Ymir shuddered faintly. Dinah didn’t know what to make of it. She feared it might be a cave-in until she identified it as a sensation she had never expected to feel again: atmospheric buffeting. She had not been this close to the surface of the Earth since she’d been launched into orbit almost a year before Zero. And if the next few minutes went well, she’d never be this close again.
The shuddering didn’t last. The graphs on her screen had all picked up little wiggles that were steadily receding into the past. “We skipped,” Markus said. “I think we will do it at least one more time.”
“Augers four and eleven are down,” Jiro announced. “I will try reversing them to clear the jam.”
This brought Dinah’s attention back. At a glance she checked all of the levels in the hoppers and saw them dropping quickly, as expected, despite the robots’ efforts to replenish them. The two that Jiro had identified were overfull, since there was no way to get the ice out of them. Dinah activated a subprogram that would put some Grabbs to work transferring surplus ice from hoppers 4 and 11 to nearby ones that could use it.
“The Caird burn worked,” Markus said, “but it gave us a little too much rotation. I am counteracting using thrusters—and this will take a little while.” He entered some commands that, presumably, turned on those of Ymir’s attitude thrusters that pushed in the opposite direction from New Caird’s big engine. “By the way, we just passed through perigee—I hope.”
Dinah glanced at the plots and saw that they had indeed passed the midway point of the maneuver. Somewhat paradoxically, though, their altitude was dropping—headed for their second, and hopefully their last, “skip” off the atmosphere.
“We’re on some weird new course now,” she said.
“It is true,” Markus said. “If we survive the next few minutes, we can fix it later.”
“Auger eleven works again,” Jiro reported, “but two and three are down. We may have a critical propellant shortage.”
“Damned thrusters are not powerful enough. We have overcorrected,” Markus said, “and now we are coming in for another skip. We are flying not only backward but upside down.”
So the burn from New Caird’s engine had done its job. It had depressed the ship’s “nose,” which was pointed backward, and prevented the stern, currently pointed forward, from digging in. They’d grazed the atmosphere with the shard’s broad side and gotten a nice skip out of it—a bounce that might’ve saved their lives. But once the shard began to rotate, it was difficult to make it stop, and now it had gone too far. The nose was pointed too steeply downward, the nozzle bell was aimed up toward space.
“So we’re thrusting down toward the planet now?” Dinah asked.
“Not enough to hurt us. Maintain thrust,” Markus ordered.
“I am running out of ice,” Jiro said, and glanced over his monitor at Dinah.
Dinah had already warned them that supplying enough propellant to do all of this in one huge burn would be a close-run thing, assuming everything went perfectly. Everything hadn’t. She met Jiro’s eyes, shook her head, and went back to work.
“Get ready to shut it down, Jiro,” Markus said. “We are descending into thick air and I don’t know what is going to happen.”
Their inner ears told them that something was happening. The powerful thrust was still driving them into their seats, but some force had taken Ymir by the nose and was torquing it around.
“We hit nose first,” Markus said, “and we are spinning back. Main engine shutdown in three. Two. One. Now.”
A nuclear steam engine didn’t shut off quickly. The thrust faltered and tapered off in response to whatever commands Jiro had entered. It was the better part of a minute, though, before they were back in zero gravity—meaning in a free orbit with no thrust pushing them around.
“I’ll give you our new orbital parameters in a minute,” Markus said. “It is complicated because we are tumbling.”
In the sudden silence that followed the engine’s shutoff, Dinah could hear distant, tinny shouting. She realized it was an open audio channel from Izzy, coming from a pair of headphones she had ripped off her head during the maneuver. It was the sound of people in the Tank. When she pulled the phones back onto her head she could tell that they were celebrating.