Seveneves. Neal Stephenson
time they go around the sun. We used to worry about those.”
“Now, not so much,” Tav put in.
Doc paused, and apparently thought better of acknowledging the joke. “Because we were worried about them, we made an effort to find them and to know their exact trajectories—their orbital parameters.”
Back to Doc and Tav, now walking across the pounded earth of the spaceport with a big truck in the background emblazoned with the Arjuna Expeditions logo.
“In recent years, companies like Arjuna Expeditions have mapped a whole lot more of those asteroids in the hopes of mining them. What we’re seeing in the last few weeks is a concerted effort by Arjuna, and an alliance of other private space companies, to throw those efforts into high gear.”
“What exactly is Sean Probst thinking, Doc?” Tav asked.
“He’s not telling us. But the science of orbital mechanics doesn’t leave a whole lot to the imagination. In Part Two of this video, you can learn more about the dance of orbiting bodies in space, and the intricate choreography needed to make an asteroid show up in the right place at the right time.”
Luisa’s finger hovered over the link that would play the next video, but before tapping it, she turned around to look at Dinah. “Just trying to figure out what you do for a living,” she said, in an accent that came from everywhere, but mostly from New York. “You’re with Arjuna, right?”
“Shh!” Dinah warned her jokingly. “I’m still trying to stay friends with the Russians.”
“What’s that about?” Luisa asked.
She was referring to a recent series of testy meetings, and sometimes out-and-out confrontations, between the Russians—still thinking and acting as a bloc under the leadership of Fyodor Antonovich Panteleimon—and the Arjuna contingent, which actually prided itself on being “disruptive.” This was a commonplace bit of biz jargon. But try explaining to a grizzled cosmonaut why being disruptive was a good thing.
Dinah was inclined to say something like “It’s cultural,” but she felt a little intimidated about using that sort of cocktail-party banter around someone with Luisa’s credentials.
“Look, surprises in space are almost always bad,” Dinah said. “Traditionally, every mission is planned out to the nth degree, and there’s a contingency plan for everything. You don’t improvise. You can’t improvise, because there’s nothing to improvise with.”
“I’m just remembering the duct tape in Apollo 13.”
“Yeah, that was one of the rare exceptions,” Dinah said, “and people are still talking about it decades later. So, to the Russians, the idea that someone can just show up unannounced, and make a claim on our resources—”
“What resources?” Luisa asked.
“They’re breathing our air,” Dinah said. “Taking up space, using bandwidth, you name it. Larz hitched a ride up here on the assumption he’d stay on Izzy and work for us—instead he’s taking off with Sean. And they are taking almost all of my robots.”
“But they’re sending more, yes?”
“Absolutely. Look, all I’m saying is that it was a surprise. And the sooner Sean and Larz get out of here, and on their way, the less likely it is that Fyodor is going to strangle them with his bare hands.”
“On their way to where?” Luisa asked.
“A different orbit.”
“Heliocentric or geocentric?” Luisa asked, deadpan, then gave Dinah a wink.
“Geocentric first. Then heliocentric,” Dinah answered with a trace of a smile.
“But I thought we were already in a geocentric orbit.”
“The wrong one, as far as Sean is concerned. Izzy’s orbit is angled with respect to the equator. It has to be that way so Baikonur can launch to it—Baikonur is as far north as Seattle. But when you are doing interplanetary stuff, which is what Sean has in mind—basically, whenever you want to get out of low Earth orbit—you want to be in an orbit that’s closer to the equator. Because that’s pretty much where the rest of the solar system is—including the big chunk of ice that Sean wants to grab and bring back here.”
“Ymir,” Luisa said, pronouncing it as she’d heard Sean do: ee-meer. A word from Norse mythology referring to primordial ice giants. Sean’s code name for a particular hunk of ice that his project had identified, and that he meant to bring back.
“Yeah. Not an official name. Sean doesn’t divulge much.”
“And how do you get from one to the other?” Luisa asked. “From a geocentric orbit—that’s what we’re in now, right?”
“Yes.”
“To a heliocentric one?”
“Well, first he’s going to have to do a plane change—from the angled Izzy orbit we’re in now, to one closer to the equator. He’ll rendezvous with the rest of his gear.”
“Why didn’t they just send everything up here?”
“Plane-change maneuvers are expensive. It’s not too bad if the only thing plane-changing is Sean and Larz and a Drop Top, but it would be ridiculously wasteful to send the whole expedition package up here only to plane-change later.” Dinah didn’t mention the other reason, which was that the biggest part of Sean’s package was so screamingly radioactive that it couldn’t be allowed anywhere near Izzy.
“Okay. But we’re still talking geocentric, right?”
“Correct, we’re still just a few hundred miles high.”
“So, how do they get from the rendezvous point to a heliocentric situation?”
“There’s a bunch of different ways to do it,” Dinah said, “but if I know Sean he’ll go through the L1 gateway.”
“I have no idea what that is,” Luisa said, then finally lost a fight to suppress a giggle. “But once again I feel that I have been dumped into a sci-fi movie when I hear people around me talking like that.”
“Doc Dubois probably covers it in that video,” Dinah said, nodding at Luisa’s tablet, “but the gist of it is really straightforward.” Looking around, she spied a mesh bag stuffed with clothing. She pulled it out of its niche and let it drift in the center of the cabin. “The sun,” she said. Now patting herself down, she found in her pocket a small plastic bottle of pills—antinausea medication she had fetched for one of the new arrivals. She opened it up and pulled out the ball of cotton stuffed into its top, then let the cotton drift in the air a little closer to Luisa. “The Earth, in its heliocentric orbit.” The sick crew member would have to wait for a few minutes. Dinah carefully tapped a few pills free from the bottle’s open neck and let them float for a moment while she pocketed the bottle. Then she began to arrange the pills in the space already staked out by the “sun” and the “Earth.”
“Asteroids?” Luisa guessed.
“These are more like abstract mathematical points,” Dinah said. “They’re called the Lagrange points, or the libration points, and there’s five of them around every two-body system. Always in the same basic geometry. Two of them, L4 and L5, are way off to the sides. I’m not going to try to show you those because we don’t have room. But the other three are all along the line running between the sun and the Earth.” She pushed off and glided to the far side of the “sun” and stationed a pill there, exactly on the opposite side from where the “Earth” was. “This is L3, very far away, invisible to us because the sun’s always in the way, not that useful.”
Gliding back toward the hovering cotton ball, she stopped herself against a bulkhead and placed a second pill out beyond it. “This is L2, outside of Earth’s