in closer to the inner planets of the star system.
It soon became plain that the comet was heading straight for a planet in the inner system, a world of blue and brown and tan, a world that was nearly all water in the southern hemisphere, and nearly all dried-out desert in the north.
The comet fell in toward the planet, closer and closer. The comet warmed as it came in nearer to the star the planet orbited. Its surface began to boil and vaporize, gases and dust blowing off into space, forming up into a tail that stretched itself out behind the comet.
The comet suddenly broke up. The fragments spaced themselves out into a neat line, like beads on a string.
The fragments moved closer, closer to the planet.
"Move from time factor positive one hundred to positive factor ten time dilation," said a disembodied voice in the darkness.
Time seemed to slow, the fragments suddenly moving at a fraction of their original velocity, easing themselves slowly down out of orbit.
"Give me a view closer to Inferno," the same voice commanded, and the image suddenly swelled in size.
"That's still way too fast. Time dilation to negative factor five," the voice ordered.
Once again, the clock slowed down, but even so, events moved quickly. The comet fragments were moving with incredible speed as they slammed into the planet's upper atmosphere, and even with time slowed to a fifth its normal speed, it still took scant seconds for the fragments to force their way down through the atmosphere and slam into the planet.
The largest fragment hit first, striking on land just north of the shoreline. The second crashed into the planet just north of the first, slamming into the peaks of a low range of hills. The other fragments struck, one after another, in a line running straight to the North Pole, blazing stars of light blooming for brief moments before they were engulfed in cloud and smoke, dust and debris
"It worked," the voice said. "Freeze sequence at that point. Simglobe off. Room lights on."
The image of the planet aflame died away, and the lights came up to reveal a perfectly ordinary living room in a perfectly ordinary residence. The only unusual object in the room was the highly sophisticated simglobe projector sitting in the center of the room.
Davlo Lentrall walked over to the low, stubby cylinder that was the simglobe unit, and tapped the top of it with his finger. Not even the most advanced Settler models could do what this unit could do. He ought to know. He had designed and built it himself. He savored the satisfaction of the moment, and all the effort that had gone before it. It was his, all his. He had discovered the comet. In a rare burst of modesty, he had named it, not for himself, as called for by tradition, but for Chanto Grieg, the murdered governor who had spurred the reterraforming project that had saved the planet. Or at least bought the planet some time, so that Davlo Lentrall and Comet Grieg could finish the work that Chanto Grieg had begun. There was a symmetry there, a bit of poetry that would appeal to the historians. Posterity would remember Davlo Lentrall, no matter what the comet was called.
Of course, there was no point in discussing such matters with his robotic assistant. Kaelor would only remind him of the things that were bound to go wrong. But Davlo could not let such a triumphant moment go without saying something. "It worked," he said at last.
"Of course the simglobe works, Master Lentrall. It has worked every time you operated it. Why should it fail now?"
"I meant the comet-capture, Kaelor, not the simulator."
"I must point out that you forced it to work," said the robot Kaelor.
"What, exactly, do you mean?" Lentrall asked. Kaelor was a useful servant, but dealing with him required a good deal of patience.
"I mean, sir, that you are making a series of unwarranted assumptions."
Davlo held back his temper, and forced himself to be patient. Kaelor had been designed and built to Davlo's custom specifications, the most important of which was to hold First Law potential to the lowest possible level when judging hypothetical situations. A lab-assistant robot with First Law set to the normally super-high levels of Infernal robots would have been utterly incapable of assisting him on the sorts of experiments Davlo was interested in. Even before he had stumbled across Comet Grieg, Davlo had been involved in Operation Snowball, a project that required