La Difference

First, Jupiter. In Io’s black sky, nothing rivals it-certainly not the sun, whose distance-shrunken disk blazes brilliant but cold, cold. Jupiter’s great orb sprawls across almost twenty degrees of sky, forty times as wide as Luna from Terra and nearly four hundred times as bright.

And when you have seen Luna once through her phases, you have seen all she has to offer. Jupiter is an ever-changing spectacle, banded clouds always swirling into new shapes, white or orange spots-cyclones that could swallow continents-bubbling up from the interior only to fade away in hours, weeks, years (or, like the Great Red Spot, not at all).

Renée Messier never tired of the show. The crawler pilot resented the attention she had to give her vehicle as she zigzagged northwards through the lava-and-sulfur uplands south of Loki toward the United European seismic station beyond the volcano.

Even more, she resented the two Japanese crawlers on her trail. The men in them would kill her if they could.

They likely could.

She used the intercom to talk to Alec Hall, who was in the seat to her right. They both wore their space armor. The Japanese invaders might hole the crawler without wrecking it. In suits they could keep going, at least until they were hit again. “Give Loki Station another call,” she said.

Hall was a geochemist by training, but all Io personnel could handle crawler equipment when they had to. She fiddled with the shortwave. Renée did not think the Japanese could pick up its signal; not many people used amplitude modulation any more. But on a world without comm satellites and with an ionosphere-even a tenuous one-the old-fashioned system made sense.

The call went out. Through her face plate, Renée saw Hall listening intently, trying to pick up the reply; even with the best static filters, Jupiter put out a lot of background noise.

His face fell. “We’re on our own,” he said bleakly. His French, the official tongue of United Europe, had a soft British accent. “They’re just starting to weld missile rails onto one of their crawlers; it won’t be ready for hours yet. By then we’ll either be there or-” He spread his gauntleted hands.

“At least they can mount weapons,” Renée growled. Her crawler was an unarmed research vehicle. No one had expected the longstanding dispute over mining rights in the asteroid belt to become a shooting war. When it did, hardly anyone thought it would spill over into the Jovian system. She shook her head. “To think I was one of the people who laughed at the waste when they mounted their missile batteries around Loki Station.”

“We were all laughing,” Alec said. “I was glad to be down at Sengen Base, where they didn’t bother with such barbarisms.” He pronounced the name of the base-which was only rubble now-with a hard “g,” English-style, instead of the proper French “j” sound.

Hoping to take his mind, and her own, off their predicament, Renée teased, “You still have trouble talking straight, eh? Such a pity, for you look much more French than I do.” No one could argue that. Alec was small, slim, dark, and sharp-featured, while her broad-shouldered frame, square craggy face, and flaxen hair might have belonged to a Dane. Vikings in the woodpile, she thought.

He turned to glare. “Merde,” he said. “How’s that?”

“Clear enough, anyhow.” She tried to smile, but her chuckle came out hollow. Being the only two people alive from a seventy-person base was too big to joke at. Had she and Alec not been out taking soil specimens from the slopes of Sengen Patera, forty kilometers away, they would have gone with everyone else when the Japanese attacked.

Typically thorough, though, the enemy had landed crawlers to finish off stragglers. They must have been fetched from the Japanese Luna Farside base, Renée thought. Only the lead she’d started with had kept them from overhauling her till now.

Not that she could hope to lose them for good. The tracks her wide, wire-wound tires were leaving would stay visible for years, until the sulfur dust raining down from Io’s volcanic eruptions finally covered them over. That dust blanketed Io’s surface, painting the moon in brilliant shades of red, orange, and yellow.

Renée yanked at the tiller, swung the crawler to the right to avoid a boulder. The dust the tires kicked up rose and fell in neat parabolic arcs. It slid off the titanium chevrons mounted on the tires’ sides for extra surface area. The design went back over a hundred years to the first lunar rover, maybe the high point of the ill-fated American space program. Engineers were natural conservatives; if something worked, they stuck with it.

“We’ve been climbing the last few kilometers,” Alec said. “Next chance we get, we ought to look back to see if we can spot the Japanese crawlers.”