"Practice. Keeps the circuits limber," Shtev explained. "Target acquisition and ranging, parallax correction, muscle alignment and tensing. .. these subroutines can get stale. Bit tables pick up holes. Have to keep them combed out."
"Did you hit anything?" he pressed, trying to see the outcrop through her very different senses.
"Yup."
"How would you know?" Roger was curious about all his friends whose systems were differently wired than his own.
"Retinal imaging says so." Shtev shrugged. "Point-nine-nine probability, anyway"
"Does that account for windage and parabolic dropoff?"
"Yup. Calibrated for Mars light gravity, even. ... Or used to be, before that module decayed to fifty-percent reliability and terminated ..."
Torraway knew about deteriorating datastreams from first-hand experience. Despite the triple redundancy built into his cyber systems and the constant checksums they took with backup units orbiting overhead, Roger's computer-controlled senses had become subject to intermittent failures. "Microseizures" he called them, when his world went black for two or three whole seconds while the backpack computer reset itself and then rebuilt his mechanical sensorium from the raw signals.
Roger understood that he was just getting old. But what the actual design-life expectancy on his mechanical and cybernetic systems was, not even the humans who had built them could say. Alexander Bradley and the rest of the interface team back in Tonka had been shooting for a uniform fifty-year mean time between failures. That would have allowed Roger to live out at least the normal human span of three score and ten.
As if he were normal anymore. Or, for that matter, human.
Still, the discoloration of his skin and the increasing frequency of those microseizures gave him cause to worry. Was it possible that Brad and the other designers had slipped up? Were there other miscalculations buried in his near-perfect Mars-adapted body, ticking away like some kind of viral logic bomb?
Torraway looked down at his own legs. Even apart from the discolorations, he was beginning to worry about his skin's surface integrity. Over the years, despite his preternaturallv accurate sense of balance and Mars's helpfully low gravity, Torraway had taken his share of tumbles and scrapes. He still had a supply of patches and quicksealer, of course, but there comes a time in the life of any garment, skin included, when the mass of patches will no longer hold together; it lacks the tensile strength of the whole cloth. The covering on Roger's lower body was approaching that moment. Worse yet, he feared the incessant radiation was doing more than changing his color: that his glossy, impervious hide might suddenly become ... brittle.
Roger's biggest concern of all, however, lived outside his body.
The fusion generator on Deimos was subject to implicit design limitations—namely, its fifty-year fuel supply. Once, back when Roger had first walked on Mars, that span had seemed like a lifetime. But now those years had almost all ticked away Torraway still felt no older, or not in the human terms of aches and pains, aside from the random glitches associated with his computer-aided senses. In fact, the excruciating surgeries that had made him Cyborg seemed to have gifted him with eternal vigor and stamina. But someday, soon, someone had better do something about the old magnetohydrodynamic reaction horn up in orbit.
He must have mentioned this worry to Fetya—or had she been listening in to the echo of his thoughts as they cycled through his backpack cyber and leached out to the computer grid?
"You know," she said, "colonials are all time building more orbital power stations. Maybe they spare you some juice?"
"Wouldn't work," Torraway replied. Each of those stations was up in geosynchronous orbit, locked in over one point on the surface and beaming its power down to a single colony complex. "If I depended on their generosity," he said aloud, "I'd be trapped within a hundred-kilometer radius of one tunnel city or another— like an Indian at a U.S. Cavalry fort."
"Which means what?"
"Uhh ... You'd say I was like a Jew in the Czar's shtetl." "Ah!"
"I don't want to be tied down."
"So, is simple. You must go back among humans. See to the refueling. Demand your rights as Mars first citizen."
"It's not that simple, Fetya. . . . That's an old-style fusion device up there, running on deuterium and tritium. The builders extracted its original fuel from Earth s oceans, but there's no setup on Mars to reprocess our limited water supplies like that. So the replacement fuel would have to come up from Earth. And that means one of the colonies would have to trade for it. In turn, they'd have to give up something the human colonists wanted more. My status as 'first citizen' just doesn't swing that much weight. Besides, I don't know the situation on Earth anymore. Nor, to be truthful, much about current Martian politics. I suspect the tension over Earths claims to Martian territory would make peaceful trading rather difficult, especially in a contraband item like fusion fuel."
"Don't know until you ask."
"But that's the humiliating part—asking."
"Humiliation? So you feel human emotions still? After so much time away?" Shtev grunted in his head. "How long since you went under pressure and talked to human people with air-driven voice?"
"Not since Sulie died. . . . Oh, and I did go back for Don Kayman's funeral, but I just stayed behind a rock and watched the burial."
"Otherwise, just monitor computer grid when suits you"
"Yeah, I listen in, sometimes."
"So? Listen in harder. Find out what colonials need. Help them get it. Humans suck up for gratitude."
"I don't know...."
"She's right, Roger!"
The voice came from his left. He turned around to see the outline of his first wife, Dorrie. She was walking lightly along beside him on the crest of a dune. Instead of a pressure suit, she wore a tiny pair of shorts and a halter, with her dark hair flying free on the feeble Martian wind. It was a bit-image that Torraway sometimes wished would decay faster than the other random dropouts in his backpack computer.
"You really should go back and talk to the administrators about your fusion generator," Dorries silvery voice warned. "Time on fuel supply is growing short ... Only eight hundred and thirty-two Martian days left! Do something about it!"
"All right, Dorrie, I'll talk to them," he agreed—if only to turn the warning image off.
"What?" Shtev asked, from his right side.
"I said I'll see to it."
"Good. Preserve us all."
Roger nodded. After a few more paces, he glanced over to his left again but Dorrie was gone. She had not even left phantom footprints in the ochre sands.
Chapter 1
She'll Be Coming Down the Fountain When She Comes
Demeter Coghlan plunged toward Mars in a blaze of glory.
The tiny passenger pod attached to the space fountain fell at an acceleration of 3.72 meters per second squared, at a rate equal to the pull of Mars's gravity. At this stage of her eight-hour descent from geosynchronous—or was that areosynchronous?—orbit down to the planet's surface, the dynamic braking of the car's magnetic couplings restrained her hardly at all. No more, really, than a shuttle rocket in reentry mode.
Coghlan s understanding of the underlying physics of the Hyde Industries, Inc. fountain technology was sketchy at best. Somewhere along the equator near a place called Tharsis Montes, a linear accelerator stood upright at the bottom of a well dug deep under the Martian surface. The accelerator shot a series of ferrite hoops, each a meter in diameter and weighing almost a kilogram apiece, straight up into the sky. Moving at some tens of kilometers per second, this fountain of objects created a tremendous kinetic energy. At the upper end of their flight, the hoop-stream entered an electromagnetic torus that functioned like the pulley wheel in a sheave block: bending the stream back on itself to descend at gravitationally increasing speeds toward the planet s surface. There the stream entered another torus which passed it across to the accelerator again, completing a closed loop of flying rings.