Kim Robinson - Red Mars

“It’ll break up, surely, and come down in a lot of places.”

“True. I wonder what Sax thinks.”

They found Sax and Frank bunched before one screen, Yeli and Ann and Simon before another. A UNOMA satellite was tracking Phobos with a telescope, and Sax was measuring the moon’s speed of passage across the Martian landscape to get a fix on its velocity. In the image on the screen Stickney’s dome shone like a Fabergé egg, but the eye was drawn away from that to the moon’s leading edge, which was blurry and streaked with white flashes of ejecta and gases. “Look how well balanced the thrust is,” Sax said to no one in particular. “Too sudden a thrust and the whole thing would have shattered. And an unbalanced thrust would have set it spinning, and then the thrust would have pushed it all over the place.”

“I see signs of stabilizing lateral thrusts,” his AI said.

“Attitude jets,” Sax said. “They turned Phobos into a big rocket.”

“They did it in the first year,” Nadia said. She wasn’t sure why she was speaking, she still seemed out of control, observing her actions from several seconds behind. “A lot of the Phobos crew was from rocketry and guidance. They processed the ice veins into liquid oxygen and deuterium, and stored it in lined columns buried in the chondrite. The engines and the control complex were buried centrally.”

“So it is a big rocket.” Sax was nodding as he typed. “Period of Phobos, 27,547 seconds. So it’s going. . 2.146 kilometers per second, approximately, and to bring it down it needs to decelerate to. . to 1.561 kilometers per second.

So, 585 kilometers per second slower. For a mass like Phobos. . wow. That’s a lot of fuel.”

“What’s it down to now?” Frank asked. He was black-faced, his jaw muscles pulsing under the skin like little biceps— furious, Nadia saw, at his inability to predict what would happen next.

“About one point seven. And those big thrusters still burning. It’ll come down. But not in one piece. The descent will break it up, I’m sure.”

“The Roche limit?”

“No, just stress from aerobraking, and with all these empty fuel chambers. . ”

“What happened to the people on it?” Nadia heard herself ask.

“Someone came on and said it sounded like the whole population had bailed out. No one stuck around to try and stop the firing.”

“Good,” Nadia said, sitting down heavily on the couch.

“So when will it come down?” Frank demanded.

Sax blinked. “Impossible to say. Depends on when it breaks up, and how. But pretty soon, I’d guess. Within a day. And then there’ll be a stretch somewhere along the equator, probably a big stretch of it, in big trouble. It’s going to make a fairly large meteor shower.”

“That will clear away some of the elevator cable,” Simon said weakly. He was sitting beside Ann, watching her with concern. She stared at Simon’s screen bleakly, showed no sign of hearing any of them. There never had been word of their son Peter. Was that better or worse than a soot pile, a dotcode name coming up on your wristpad? Better, Nadia decided. But still hard.

“Look,” Sax said, “it’s breaking up.”

The satellite telescopic camera gave them an excellent view. The dome over Stickney burst outward in great shards and the crater pit lines that had always marked Phobos suddenly puffed with dust, yawning open. Then the little potato-shaped world blossomed, fell apart into a scattering of irregular chunks. A half a dozen large ones slowly spread out, the largest one leading the way. One chunk flew off to the side, apparently powered still by one of the rockets that had lain buried in the moon’s interior. The rest of the rocks began to spread out in an irregular line, tumbling each at a different speed.

“Well, we’re kind of in the line of fire,” Sax remarked, looking up at the rest of them. “The biggest chunks will hit the upper atmosphere soon, and then it’ll happen pretty quickly.”

“Can you determine where?”

“No, there’s too many unknowns. Along the equator, that’s all. We’re probably far enough south to miss most of it, but there may be quite a scatter effect.”

“People on the equator ought to head north or south,” Maya said.

“They probably know that. Anyway the fall of the cable probably cleared the area pretty effectively already.”

There was little to do but wait. None of them wanted to leave the city and head south, it seemed they were past that kind of effort, too hardened or too tired to worry about longshot risks. Frank paced the room, his swarthy face working with anger; finally he couldn’t stand it, and got back on his screen to send off a sequence of short pungent messages. One came back in, and he snorted. “We’ve got a grace period, because the U.N. police are afraid to come down here until after the shit falls. After that they’ll be on us like hawks. They’re claiming that the command initiating the Phobos explosions originated here, and they’re tired of a neutral city being used as a command center for the insurrection.”

“So we’ve got until the fall is over,” Sax said.

He clicked into the UNOMA network, and got a radar composite of the fragments. After that there was nothing to do. They sat; they stood and walked around; they looked at the screens; they ate cold pizza; they napped. Nadia did none of these things. She could only manage to sit, hunched over her stomach, which felt like an iron walnut in her. She waited.

Near midnight and the timeslip, something on the screens caught Sax’s attention, and with some furious typing on Frank’s channels he got through to the Olympus Mons observatory. It was just before dawn there, still dark, and one of the observatory cameras gave them its low space view southward, the black curve of the planet blocking the stars. Shooting stars were blazing down at an angle out of the western sky, as fast and bright as if they were perfectly straight lightning bolts, or titanic tracer bullets, spraying in a sequence eastward, breaking apart in the last moments before impact, causing phosphor blobs to burst into existence at every impact point, like the first moments of a whole string of nuclear explosions. In less than ten seconds the strike was over, leaving the black field dotted with a line of glowing yellow smoke-obscured patches.

Nadia closed her eyes, saw swimming afterimages of the strike. She opened them again, looked at the screen. Clouds of smoke were surging up into the predawn sky over west Tharsis, pouring so high that they got up out of the shadow of the planet and were lit by the rising sun; they were mushroom clouds, their heads a bright pale pink, their dark gray stalks illuminated by reflection from above. Slowly the sunlight moved down the tumultuous stalks, until they were all burnished by the new morning sun. Then the lofty line of yellow and pink mushroom clouds drifted across a sky that was a delicate shade of indigo pastel: it looked like a Maxfield Parrish nightmare, too strange and beautiful a sight to believe. Nadia thought of the cable’s last moment, that image of the incandescent double helix of diamonds. How was it that destruction could be so beautiful? Was there something in the scale of it? Was there some shadow in people, lusting for it? Or was it just a coincidental combination of the elements, the final proof that beauty has no moral dimension? She stared and stared at the image, focused all her will on it; but she could not make it make sense.

“That may be enough particulate matter to trigger another global dust storm,” Sax observed. “Although the net heat addition to the system will surely be considerable.”

“Shut up, Sax,” Maya said.

Frank said, “It’s about our turn to get hit, right?”