The Sparrow - Mary Doria Russell [48]
At first, only Sofia saw what he was driving at. "Yes," she said, glad to be distracted by him for once. "The asteroids aren’t bad, really. The miners’ quarters can be rather comfortable—"
"Yeah, sure," George said. "You’ve already got the mass-drivers grafted on and the lifepod in place. Get a big enough asteroid and you could just keep feeding slag into the engines. We do it now on a small scale to bring the rocks into Earth orbit from the asteroid belt. I thought years ago that you could go as far as you wanted, if you got a big enough rock. There just wasn’t any reason to leave the solar system."
"Until now," Emilio said.
"Until now," George agreed.
"Did I miss something?" Anne said. "Asteroids?"
But George was starting to laugh and Emilio looked positively beatific. "Sofia," George said, "tell Anne about that contract you had—"
"—with Ohbayashi," Sofia finished for him. She looked at Anne and then the others, and gave a small astonished laugh before saying, "It was just before working with Dr. Sandoz in Cleveland. I did an expert system for Ohbayashi’s asteroid mining division. They specified an AI program that could take into account the cost of remote assaying and the costs of capturing an asteroid, mining and refining the minerals in space, versus the projected market values of the product at delivery, Earthside. Very little intuition involved, except projecting future metals prices," she said wryly. "You’re right, Dr. Sandoz. A partially mined asteroid could be used as a vehicle."
Emilio, who had been leaning forward and watching her carefully as she spoke, clapped once and sat back in his chair, smiling broadly.
"But it would take four years, wouldn’t it?" Anne objected.
"Four years isn’t so bad," Emilio said.
"Whoa," Jimmy said, looking at Sofia and Sandoz. "Okay, first off, it’s four point three and it’s light years, not plain solar years. Even a third of a light year is a nontrivial distance. And anyway, that’s the time it takes for light and radio waves to travel the distance, not a ship. It would take a ship a lot longer ... but even so ..." he said, starting to think about it now.
George gestured for Sofia’s notebook and stylus. Emilio saved his file and handed it over. "Okay, so do the problem," George said, blanking the screen so he could sketch the idea out on the tablet. "At thirty-two feet per second per second, you’d have one G of gravity. Say you accelerate for half the trip and then rotate the rock a hundred and eighty degrees and decelerate for the second half..."
For a while there was no sound except the muttering of numbers and the tapping of a keyboard, Jimmy beginning the calculations on-line as George continued them by hand. George finished his estimate first, to Jimmy’s irritation. "You’d need about seventeen years to get there, not four." Emilio looked both crestfallen and startled by the difference. "Hell," George told him, "Anne was in graduate school longer than that!" Anne snorted but George went on, "What if you kept a normal sleeping and waking schedule and bumped the engines up for two Gs while the crew’s flat in bed? That would cut the time down and get you closer to light speed, so you’d get some help from relativity. Make the trip seem faster to the people onboard."
Jimmy continued to work on his own line of calculation. "No, wait. It might seem to the crew more like six or seven months."
"Six or seven months!" Emilio exclaimed.
"Jeez," Jimmy said, staring at the numbers. "You could get real close to light speed in less than a year or so, even at one G, constant acceleration. Like maybe ninety-three percent. Anybody want to take on Einstein? I wonder if you’d run out of rock... How big would the asteroid have to be?" he asked himself and went back to the calculations.
"Wait a minute. I don’t understand about people sleeping," Anne said. "Wouldn’t you have to have somebody awake all the time