Based on your current refined estimates of the work required once the comet is located, calculate the most likely length of time left between now and when the work must commence."
"Therrree are mannny vvarrriables," the doubled voice replied. "Weee willll attemmmpt a usseful appproximaation." There was a brief pause and then one of the two voices, the higher-pitched, feminine-sounding one, spoke by itself. "Twelve standard days, four standard hours, and fifty-two standard minutes. I should note that estimate is based on having the complete comet task force in order and on standby for immediate launch."
"Very good," said Kresh. "Based on the best current data and the current search schedule, what are the odds of relocating Comet Grieg within twelve standard days?"
"Theee oddss arrre approximatellly onnne inn elllevennn, or approximately nine percent," the double voice replied.
"Give us a range of representative values," Kresh said.
The deeper-pitched, mechanical voice spoke by itself. "In percentile terms, odds are point five percent for relocation in one day. One point two percent in three days. Four percent in six days. Six point one percent in eight days. Nine percent in twelve days. Twenty percent in fifteen-"
"When do the odds reach, oh, ninety-five percent?"
The feminine voice took over. "The odds improve rapidly as possibilities are rejected and the search area is reduced. At the same time, the comet is growing closer, and beginning to increase in brightness as it is heated by the sun. This also helps. The odds for relocation pass the ninety-five percent point in about twenty-six days."
"Too little, too late," said Fredda.
"Yes," said Alvar, his tone of voice saying far more than that single word. He sighed. "Deep space all around, but I'm tired," he said. "All right, Units Dum and Dee. That will be all." He signaled for Donald to cut the connection.
Fredda watched her husband as he stared straight ahead at the blank wall in front of him, a deep frown on his face. "One chance in eleven," he said. "Is that what it comes down to? The planet has a nine percent chance, if we do everything exactly right?"
"It could be," Fredda said, returning to the couch and sitting next to him. "Are we doing everything, and are we doing it right?"
Alvar Kresh rubbed his eyes. "I think so," he said, and yawned hugely. "I can't remember the last time I really slept." He shook his head and blinked a time or two. "I've got a spaceside team working around the clock, getting the equipment together to make the intercept. We haven't started on the actual evacuation of the Utopia region yet-and I hope to the devil that Beddle hasn't just started a panic out there with that little speech. But we're getting the evac plan ready to go. The area's pretty thinly populated, and Donald tells me the people who know these things feel it would be better to take a bit more time planning, even if it means starting a bit later."
"One thing I can tell you your evacuation experts might not have told you," said Fredda. "Make sure it's a total evacuation, and that you can prove it's total. Leave one person there-or even leave open the possibility that one person is out there-and you're going to be knee-deep in overstressed Three-Law robots trying to pull off a rescue."
"I'm not going to worry about losing a few robots in comparison to saving the whole planet."
"No, of course not," Fredda said. But she thought of Kaelor's death a few hours before, and could not help but wonder if she would be quite as careless about the lives of robots in the future. "But those robots could cause a great deal of trouble. Even if you can prove there's no one left in all of Utopia, a lot of robots are going to feel strong First Law pressure to stop the comet impact, any way they can. After all, the comet sure as hell represents danger to humans. More than likely, someone is going to die in a building collapse or an aircar caught by the shockwave, or whatever."
"Maybe so, but how could the robots stop it?" Kresh asked.
"For starters, is that an all-human crew on the spaceside team? You have to assume that any robots on that job will do their best to sabotage the job. Even a low-function fetch-and-carry robot will have enough capacity to realize that an incoming comet represents danger."
"Burning devils," said Kresh. "I hadn't thought of that. I hope someone else has, but we've got