Red Mars. Kim Stanley Robinson

long months, but it was still less than half their trip. And none of their carefully designed physical surroundings or daily routines could hasten its end.

      Then one morning the second flight team was dealing with another of Arkady’s problem runs, when all at once red lights burned on several screens.

      “A solar flare has been detected by the solar monitoring equipment,” Rya said.

      Arkady stood quickly. “That’s not me!” he exclaimed, and leaned over to read the screen nearest him. He looked up, met his colleagues’ skeptical stares, grinned. “Sorry, friends. This is the real wolf.”

      An emergency message from Houston confirmed him. He could have faked those as well, but he was headed for the nearest spoke and there was nothing they could do; fake or not, they had to follow.

      In fact, a big solar flare was an event they had simulated many times before. Everyone had tasks to perform, quite a few of them in a very short time, so they ran around the toruses, cursing their luck and trying not to get in each other’s way. There was a lot to do, as battening down was complicated and not very automated. In the midst of dragging plant trays into the plant shelter Janet yelled, “Is this one of Arkady’s tests?”

      “He says not!”

      “Shit.”

      They had left Earth during the low point in the eleven-year sunspot cycle, specifically to reduce the chance of a flare like this occurring. And here it was anyway. They had about half an hour before the first radiation arrived, and no more than an hour after that the really hard stuff would follow.

      Emergencies in space can be as obvious as an explosion or as intangible as an equation, but their obviousness has nothing to do with how dangerous they are. The crew’s senses would never perceive the subatomic wind approaching them, and yet it was one of the worst things that could have happened. And everyone knew it. They ran through the toruses to get their bit of battening done – plants had to be covered or moved to protected areas, the chickens and pigs and pygmy cows and the rest of the animals and birds had to be herded into their own little shelters, seeds and frozen embryos had to be collected and carried along, sensitive electrical components had to be boxed or likewise carried along. When they were done with these high-speed tasks they yanked themselves up the spokes to the central shaft as fast as they could, and then flew down the central shaft tube to the storm shelter, which was directly behind the tube’s aft end.

      Hiroko and her biosphere team were the last ones in, banging through the hatch a full twenty-seven minutes after the initial alarm. They hurtled into the weightless space flushed and out of breath. “Has it started yet?”

      “Not yet.”

      They plucked personal dosimeters from a velcro pad of them, pinned them to their clothing.

      The rest of the crew already floated in the semi-cylindrical chamber, breathing hard and nursing bruises and a few sprains. Maya ordered them to count off, and was relieved to hear the whole hundred run through without gaps.

      The room seemed very crowded. They hadn’t gathered the whole hundred in one spot for many weeks, and even a max room didn’t seem large enough. This one occupied a tank in the middle strand of the hub shaft. The four tanks surrounding theirs were filled with water, and their tank was divided lengthwise between their room and another semi-cylinder that had been filled with heavy metals. This semi-cylinder’s flat side was their “floor,” and it was fitted inside the tank on circular tracks, and rotated to counteract the spin of the ship, keeping the tub between the crew and the sun.

      So they floated in a non-rotating space, while the curved roof of the tank rotated over them at its usual four rpm. It was a peculiar sight, which along with the weightlessness made some people begin to look thoughtful in a pre-seasick kind of way. These unfortunates congregated down at the end of the shelter where the lavatories were located, and to help them out visually, everyone else oriented themselves to the floor. The radiation was therefore coming up through their feet, mostly gamma rays scattering out of the heavy metals. Maya felt an impulse to keep her knees together. People floated in place, or put on velcro slippers to walk over the floor. They talked in low voices, instinctively finding their next-door neighbors, their working partners, their friends. Conversations were subdued, as if a cocktail party had been told that the hors d’oeuvres had been tainted.

      John Boone rip-ripped his way to the computer terminals at the fore end of the room where Arkady and Alex were monitoring the ship. He punched in a command, and the exterior radiation data were suddenly displayed on the room’s biggest screen. “Let’s see how much is hitting the ship,” he said brightly.

      Groans. “Must we?” exclaimed Ursula.

      “We might as well know,” John said. “And I want to see how well this shelter works. The one on the Rust Eagle was about as strong as the bib you wear at the dentist’s.”

      Maya smiled. It was a reminder, rare from John, that he had been exposed to much more radiation than any of the rest of them – about a hundred and sixty rem over the course of his life, as he explained now in response to someone’s question. On Earth one caught a fifth of a roentgen equivalent man per year; orbiting Earth, still inside the protection of the Earth’s magnetosphere, one took around thirty-five per year. So John had taken a lot of heat. And somehow that gave him the right, now, to screen the exterior data if he wanted to.

      Those who were interested – about sixty people – clumped behind him to watch the screen. The rest relocated at the far end of the tank with the people worrying about motion sickness, a group that definitely didn’t want to know how much radiation they were taking. Just the thought was enough to send some of them into the heads.

      Then the full force of the flare struck. The exterior radiation count shifted to well above the solar wind’s usual level, and then soared in a sudden rush. An indrawn hiss came from several observers at once, and there were some shocked exclamations.

      “But look how much the shelter is stopping,” John said, checking the dosimeter pinned to his shirt. “I’m still at 1.3 rem.”

      That was several lifetimes of dentists’ X-rays, to be sure; but the radiation outside the storm shelter was already 70 rem, well-on its way to a lethal dose, so they were getting off lightly. Still, the amount flying through the rest of the ship! Billions of particles were penetrating the ship and colliding with the atoms of water and metal they were huddled behind; hundreds of millions were flying between these atoms and then through the atoms of their bodies, touching nothing, as if they were no more than ghosts. Still, thousands were striking atoms of flesh and bone. Most of those collisions were harmless; but in all those thousands, there were in all probability one or two (or three?) in which a chromosome strand was taking a hit, and kinking in the wrong way: and there it was. Tumor initiation, begun with just that typo in the book of the self. And years later, unless the victim’s DNA luckily repaired itself, the tumor promotion that was a more or less unavoidable part of living would have its effect, and there would appear a bloom of Something Else inside: cancer. Leukemia, most likely; and, most likely, death.

      So it was hard not to regard the figures unhappily. 14.658 rems, 1.786, 19.004. “Like an odometer,” Boone said calmly as he looked at his dosimeter. He was gripping a rail with both hands and pulling himself back and forth, as if doing isometric exercises. Frank saw it and said, “John, what the hell are you doing?”

      “Dodging,” John said. He smiled at Frank’s frown. “You know – moving target!”

      People laughed at him. With the extent of the danger precisely charted on screens and graphs, they were beginning to feel less helpless. This was illogical, but naming was the power that made every human a scientist of sorts. And these were scientists by profession, with many astronauts among them as well, trained to accept the possibility of such a storm. All those mental habits began channeling their thoughts, and the shock of the event receded a bit. They were coming to terms with it.

      Arkady went to a terminal and called up Beethoven’s Pastoral Symphony, picking it up in the third movement, when the village dance is disrupted by storm. He turned up