La Difference

“Good idea.” Renée pulled behind the first outcrop of stone large enough to shield the crawler from view from behind: if the enemy was close, no use presenting a stationary target. She cautiously raised the outside video camera on its motorized boom until it could peek over his shelter. A radar pulse, of course, would have fingered the Japanese at once, but also would have screamed “Here we are!” to their detectors.

She panned the camera back and forth, peering at the screen to pick up motion against the colorful landscape. A flash of light made her gasp, but it was only the sun reflecting from a patch of sulfur dioxide snow.

“There!” Alec said suddenly. “No, go back, you lost it.” Renée reversed the camera control, stabbing at the stop button. Then she also saw the two moving insectile specks. They traveled side by side, tiny as midges in the distance.

“How far away are they, do you think?” Alec asked.

“We passed that very red patch there, hmm, what would you say, fifteen minutes ago? So they’re ten kilometers behind us, possibly twelve.”

“They’ve gained a lot of ground,” Alec said, his voice low and troubled.

Messier shrugged, a Gallic gesture that did not suit her. “Why shouldn’t they? They only have to follow a trail, not make one.”

“They’ll catch us long before we get to Loki Station.”

“I know. But we’re not caught yet. As long as they’re not shooting at us, I refuse to worry.” Out loud, at any rate, she amended to herself.

She lowered the camera and started traveling again. A few minutes later, she began cursing in earnest, for the crawler came up against a long scarp lying square across the path. Such cliffs were common on Io, where the sulfurous crust often fractured under pressure. This one was a good two hundred meters high, and much too steep to climb. Getting around it wasted half an hour and took her farther from Loki Station.

“Hot spot ahead,” Alec warned, his eyes on the infrared sensor. “Temp is up around twenty Celsius.”

“Thank you.” Messier drove around it. Most of Io’s surface was as cold as one would expect for a world more than three quarters of a billion kilometers from the sun, down around -145° C. But, especially in the volcanic equatorial regions, black sulfur from the lower part of the mantle could force its way to the surface. It soon got covered by sulfur dust like the rest of Io, and was hard to spot visually.

Alec went aft to put a fresh canister of lithium hydroxide in the air recycler. Renée hardly noticed him getting up; she was intent on putting kilometers behind them to make up the delay from the scarp.

She jumped when the incoming signal lamp lighted. It was not a call from Lola station, but on the ordinary deep-space band. She accepted the signal. A voice sounded in his headphones-badly accented French: “Stop in place and we will accept your surrender. Otherwise you will be destroyed.”

“Thank you, no.” Renée did not bother transmitting the reply. When the Japanese remilitarized in the early years of the twenty-first century, they went back all too closely to the traditions of bushido. Dying at once was usually better than falling into their hands, even for a man. Giving up did not bear thinking about, not for her.

A missile slammed into the ground about ten meters to the crawlers right. Rocks and chunks of sulfur rained down. The only thing that saved the crawler from worse damage was that Io’s atmosphere was too thin to transmit the blast from the explosion.

Fear knotting her guts, Renée fed emergency power to the electric motors in each wheel hub. She slewed the crawler leftwards, dashing for the shelter of a ridge of rock. She got there just in time; the missile from the pursuer, which had been homing on her, blew itself up against the suddenly interposed barrier.

“Cochons!” she cried, shaking her fist at the Japanese. Then reaction set in. Sweat oozed over her skin, the clammy, clinging sensation made worse by its lazy flow in Io’s .18g. If they’d been in the open when that second missile struck-With an almost physical effort, she forced herself to optimism. “We’ve gained some time, at any rate,” he said. “They’ll have to suit up and EVA to reload their missile racks.”

“You’re right.” Alec came forward to strap himself in again. He rubbed at his hip through the space armor; Rente’s desperate maneuver must have thrown him head over heels. But he still sounded as calm and practical as if the discussion were about the best place to dig a sample trench. “The eclipse will slow them, too.”

“Eclipse?” Renée echoed foolishly; she hadn’t consciously noticed how narrow Jupiter’s crescent had become. The planet, of course, hung unmoving in the sky; from Loki, it stood about forty degrees above the horizon, slightly south of west. But the sun was within a few degrees of it, and would soon vanish behind its bulk.