Seveneves - Страница 51

“And they are proving their identity by mentioning numbers that could be known only to a few people. I get it.”

“And all I’m saying is that a really sophisticated troll would look for some detail like that, in the background of a NASA publicity photo, as a way to fool you.”

“Noted,” Dinah said. “But I doubt it.”

“Who do you think it is, then?”

“Sean Probst,” Dinah said. “I think it’s the Ymir expedition.”

Doob got a distracted look. “Man, I haven’t thought about those guys in ages.”

IT WAS STRANGE THAT A STORY AS EPIC AND AS DRAMATIC AS THE voyage of Ymir could go forgotten, but those were the times they lived in.

The ship had stopped communicating and then disappeared against the backdrop of the sun about a month after its departure from low Earth orbit (LEO) around Day 126. A few sightings on optical telescopes had confirmed that it had transitioned into a heliocentric orbit, which might have happened accidentally or as the planned result of a controlled burn. Assuming it was following its original plan, Ymir should then have made almost two full loops around the sun. Since its orbit was well inside of Earth’s — the perihelion was halfway between the orbits of Venus and Mercury — it would have done this in just a little more than a year, grazing the orbit of Greg’s Skeleton — Comet Grigg-Skjellerup — a couple of hundred days ago. But this would have occurred when it was on the far side of the sun from the Earth, making it difficult to observe. The next event would have been a small matter of impregnating the comet’s core, or a piece of it, with an exposed nuclear reactor on the end of a stick, and then turning it on to generate thrust by blowing a plume of steam out the entry hole. They would have done a large “burn”—pulling out the reactor’s control blades, powering it up, and releasing a plume of steam — that would have altered the comet’s trajectory by about one kilometer per second, enough to put it on a collision course with Earth, or at least with L1, a couple of hundred days later. The timing was awkward, and many had griped about it, wondering why Sean hadn’t gone after some other comet, or plotted some other course that might have brought it home a little sooner. But people who knew their way around the solar system understood that it was near-miraculous good fortune for any comet core to be in a position to be grappled and moved in such a short span of time. The hasty shake-and-bake nature of the Ymir expedition, which had stirred up so much controversy, had been forced by the implacable timeline of celestial mechanics. Time, tide, and comets waited for no man. And even if it had been possible to bring a comet back sooner, it would have been reckless, and politically impossible. What if the calculations were wrong and the comet slammed into the Earth? So, the plan of the Ymir expedition was the only one that could have worked.

If, indeed, it were working at all. And since much of the action — the rendezvous with the comet and the “burn” of the nuke-powered, steam-fueled engine — had occurred while it was on the far side of the sun, this had been very much in doubt until a couple of months ago, when astronomical observations had proved conclusively that Comet Grigg-Skjellerup had changed its course — something that could only have happened as the result of human intervention. The comet was headed right for them. It would have triggered mass panic on Earth had Earth not already been doomed. Since then they had watched its orbit converging slowly with that of Earth, and plotted the time when it would disappear against the sun once more as it reached L1. The reactor would then have to be powered up again, as a huge “burn” would be needed to synchronize Ymir’s orbit with Earth’s and pilot it through L1 to a long ellipse that would bring it their way.

“I THINK ABOUT THEM EVERY DAY,” DINAH ANSWERED.

“When are they supposed to hit L1?”

“Any time. . but it’s going to be a long burn, they might sort of grease it in over a period of a few days rather than trying to do one sharp impulse.”

“Makes sense,” Doob said. “One high-gee maneuver might cause the ice to break apart. When was the last time they communicated?”

“On the X band? The real radio? A few weeks after they left. Almost two years ago. But clearly they’re still alive. So it must have been radio failure.”

“Well, let’s go with that theory,” Doob suggested. “Jury-rigging a new radio that would transmit over such a distance would be kind of hopeless. The best they could hope for would be to cook something up that might work when they got closer. . and to settle for lower bandwidth.”

“My dad used to talk about spark gap transmitters,” Dinah said. “It was a technology they used—”

“Back before transistors and vacuum tubes. Yes!” Doob said.

Dinah telegraphed down:

DOES QET SOUND LIKE AN OLD TIME SPARKY TO YOU?

Rufus returned:

YES COME TO THINK OF IT

“They took some of my robots with them,” Dinah said. “All they would have to do is jot down the MAC addresses on those units’ interface boards, and they’d have sort of a crude proof of identity. As a matter of fact. .” and she began to pull up some of the records she had made, almost two years ago, of the robots and part numbers issued to Sean and his crew. Within a few minutes she was able to verify that the MAC address that had come in via Morse code a few minutes ago matched one on a robot that had been taken to Ymir.

“Who has access to the file you just consulted?” Doob asked, still in devil’s advocate mode.

“Are you kidding? You know how Sean is with the encryption and everything? All of this stuff is locked down. I mean, I’m sure the NSA could get in, but not some random prankster.”

“Just checking,” Doob said. “It seems awfully roundabout, is all I’m saying. Why doesn’t he just broadcast something like ‘Hey, Dinah, it’s me, Sean, my radio’s busted’? That would seem easier.”

“You have to know Sean,” Dinah said. “Look. Anything he sends out over that channel is getting broadcast to basically the entire Earth. It’s going to go up on the Internet. . everyone’s going to know his business. He has no idea what the situation is. There’s no Internet up there and his radio’s been out for a long time. He doesn’t even know if anyone is alive up here. Or if there’s been a military coup or something. He doesn’t want to come back here if we’ve turned into the Klingon Empire.”

“I think you’re right,” Doob said. “He’s going to ease into it, test the waters.”

Forty-five minutes later Dinah was taking down a new message from QET. It started with RTFM5, then the number 00001, and went on as an apparently meaningless series of random letters.

“The only part I understand is ‘read the fucking manual,’” Dinah said, “followed by the number five.”

“Did he bring any manuals up with him?”

“He brought a bunch of stuff,” Dinah said, “from the engineers in Seattle, and left some of it here. .”

“You have a faraway look in your eye, Dinah. .”

“I remember asking him, ‘Why did you print that stuff out, why not use thumb drives like everyone else,’ and he said, ‘Owning your own space company brings some perks,’” Dinah said.

She found them after a few minutes’ rummaging in storage bins: half a dozen three-ring binders, volumes 1 through 6 of the Arjuna Expeditions Employee Manual. The entire stack was a foot thick.

Doob whistled. “Given the cost per pound of launching stuff into space, this is probably worth more than the Gutenberg Bible that showed up last week.”

They went straight to volume 5, which for the most part looked like any other corporate employee manual. But in between the sexual harassment policy and the dress code was a half-inch-thick stack of pages with no readable content at all. Random sequences of capital letters had been printed all over them, in groups of five, column after column, row after row, all the way down each page. Each of these pages had a different number at its top, beginning with 00001.

“This is the boy adventure secret code shit that Larz always used,” Dinah said. “But I’ll be damned if I know—”

“I’m embarrassed to say that I know exactly what this is,” Doob said. “These are one-time pads. It’s the simplest code there is — but the most difficult to break, if you do it right. But you have to have this.” And he rattled page 00001 in his hand.

Once Doob had explained how it worked, Dinah was able to begin decrypting the message by hand, but in a few minutes Doob had written a Python script that made it easy to finish the job. “I came here thinking I was going to have a drink and a chat about asteroid mining,” he said.

“Oh, stop grumbling — this is way more interesting!” Dinah said.

The message read:

TWO ALIVE. THRUSTING AT FULL POWER. SEND SITREP.

“There were six in the original crew, right?” Doob asked.

“Something must have happened,” Dinah said. “Maybe they hit a rock or something, damaged the antenna, lost some people. Maybe the radiation got to them.”

“Well, it sounds like they are coming back,” Doob said.

“Yeah, unless—”

“Unless what?”

“Unless he just wants to hang out at L1. That would be a hell of a lot safer. I don’t think any moon shards are going to make it out that far.”