Seveneves: A Novel by Neal Stephenson Page B

small enough to hold in one hand. Normally this would have been a bad idea—a single cosmic ray might shoot through the entire stack and kill every board at once. She handed it off to an eight-legged robot and sent that robot through the airlock and down the tunnel. Seeing through the remote eye of its video camera, manipulating a data glove connected to its grappling arms, she maneuvered it into the niche and then made it splay out its arms and go rigid so that it couldn’t drift out. Her transistors were now safe.
    Rhys watched her do it. He had been on Izzy for five hours. He was too sick to do anything except lie very still. Dinah, whose shop was full of zip ties and clamps and other useful devices, had helpedhim wedge his head between a couple of pipes, padding them with foam to make it a little more comfortable. She had left him with a supply of barf bags and gone about her work.
    “What do you call that type?” he asked.
    “A Grabb,” she answered. “Short for Grabby Crab.”
    “Good name, I suppose.”
    “It’s the most obvious body type for something that’s meant to pick its way around on a rock. Each leg has an electromagnet on its tip, so it can stick to Amalthea, which is mostly iron. When it wants to pick up that foot, it just switches off the magnet.”
    “I’m sure you’ve already thought of this,” Rhys said delicately, “but you could hollow out the whole asteroid this way. Create a shielded environment. Maybe even fill it with air.”
    Dinah nodded. She was busy, placing the Grabb’s eight arms one by one, making sure each of them was stuck to a wall of the niche. It would be embarrassing if all of her vitamins floated out and got lost. “We’ve discussed it. Me and the, like, eight thousand engineers on the ground who are working on this.”
    “Yes, I didn’t suppose it was a solo effort.”
    “The constraint is working gas. The plasma cutters are very powerful, but they require some gas flow. Almost any gas will do. But industrial gases are rare and valuable up here, and they have this annoying habit of escaping into space.”
    “But if you were hollowing something out, as opposed to working on its surface—”
    “Exactly,” Dinah said. “You could seal the exits and recapture the used gas, and recycle it.”
    “So you’re way ahead of me, in other words.”
    Dinah’s upper face was obscured in a VR rig but a smile spread below it. “That’s the thing about space,” she said. “So many smart people are so interested in it that it’s difficult to come up with a really new idea.”
    There was a pause in the conversation while she switched control to a different robot and got it moving down the tunnel.
    “Moving my eyeballs oh so slightly, I see at least three other morphologies in your bestiary.”
    “The Siwi is adapted from a robot that was made for exploring collapsed buildings. Which in turn was obviously adapted from a snake.”
    “A sidewinder, presumably, given the name.”
    “Yeah. The electromagnets are arranged around the Siwi’s body in a double helix, so by turning some on and others off, it can sort of roll diagonally along the surface with minimal power usage.”
    “The thing that looks like a Buckyball seems to be using a similar trick.”
    “You nailed the name. We do in fact call those Buckies. Technically speaking, it’s a thing called a—”
    “Tensegrity.”
    Dinah felt herself blushing. “Of course, you’d know all about those. Anyway, because it’s big and roughly spherical, it can roll in any direction by playing tricks with electromagnetics and making its struts get longer or shorter. The brains live in that sort of nucleuslike package suspended in the middle.”
    “Grabbs, Siwis, and Buckies. What do you call the tiny ones?”
    “Nats. Our attempt to build a swarm. Lina’s been moonlighting on it.”
    There was a little gap in the conversation while both of them considered the unfortunate choice of wording.
    “It’s pretty