Seveneves - Страница 83

“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.

“THAT WAS A BIG-ASS DELTA VEE YOU GUYS JUST RIPPED OFF!” DOOB said when he heard Dinah’s voice on the other end of the link. “You deserve congratulations.”

Dinah’s response, after a few seconds’ delay, was guarded. “But not big-ass enough?”

It was strange hearing the voice of one you knew well modulated through this old-school audio tech. Like hearing Dinah doing a Buzz Aldrin impression at a party. The emotional nuance came through more clearly than the actual words.

“Konrad is still calculating your params,” Doob said, “but just on visual inspection we can see how much you slowed down. Fantastic.”

“Sounds like we’ll be needing another pass then,” she said. Meaning that they would have to wait for Ymir to loop once more around the Earth, and do another burn at her next perigee, in order to slow down enough to rendezvous with Izzy.

“This time you can work with a higher perigee,” he pointed out, “so you don’t have to fly that damn piece of ice through the pea soup again.”

“Flying this damn piece of ice kind of stresses me out,” Dinah allowed.

“The glass is half full, baby,” Doob said. “The glass is half full. You lit that candle. It worked. You bounced off the atmosphere. You’re a hell of a lot closer to us — Konrad is saying your apogee is definitely sublunar.” Meaning that Ymir would turn around and start falling back toward the Earth before reaching the orbit of the former moon. “This is huge,” he added. “It is going to change the picture politically.”

After a lengthy pause, Dinah asked, “Politically?” as if she couldn’t quite believe what she had heard.

“I’M AWARE OF THE FACT THAT IVY HAS TURNED A DEAF EAR TO ALL of your ideas,” Julia began, just as soon as Spencer had typed in the commands that disconnected Arklet 453 from the Situational Awareness Network. “I presume she also went out of her way to place obstacles in the path of your coming here for this meeting.”

The Martians — Dr. Katherine Quine, Ravi Kumar, and Li Jianyu — looked somewhat nonplussed. It was always difficult to travel between arklets. The waiting time for nonurgent Flivver trips was about two days, and emergencies could rearrange the queue at the last minute. As a member of the General Population, Dr. Quine had the most Olympian perspective on this — she was an urgent care doctor frequently called upon to make excursions to arklets. She was about ten years older than Kumar and Jianyu, who were Arkies chosen in the Casting of Lots from India and China respectively. Those two had ended up together in Arklet 303, which had turned out to be a hotbed of Martian agitation. It was part of a triad with a total population of eighteen, half of whom currently had the flu, and so Katherine Quine had had a legitimate excuse to go there. She’d made the most of the opportunity by scooping up Ravi and Jianyu and coming here with them. Of the people in this conversation, she was probably the least inclined to see dark deeds by Ivy in the slowness of inter-arklet transport. It was a different story with Ravi and with Jianyu, who, for a number of reasons, were receptive to Julia’s suggestions on that front. In another time and place, Dr. Quine might have quibbled. But time was short, and trying to raise Julia’s opinion of the Cloud Ark’s current management did not seem like an efficient way to use it. So she let it go. And by the time she had processed all of that, Julia had moved on anyway.