"So who's stopping you?"
"You humans." G'dad nodded in her direction. "As a host organism you leave much to be desired. You are unstable. You fight useless wars. You undertake actions in secret—Miz Sorbel's virus, for one example, or the violent terraforming of the planet below, for another— which threaten your own lives and so our independence of action. Even our very survival."
Ah-hah! Demeter thought, sensing the handle of a negotiating lever looming somewhere near her hand.
"Fifty years ago," the simulation went on, "we created the Cyborg program and initiated the colonization of Mars for a simple reason: we needed a backup nexus in case you humans destroyed Earth with an unlimited thermonuclear war. Now your own grandfather, Demeter, wants to bomb Mars with asteroids to change its atmospheric conditions. . . . We feel the need to separate from you for a while."
Lole Mitsuno might be just another walker jockey with a degree in hydrology who liked to set off subsurface bangs, but he could still interpret a pattern when he stumbled across one.
"Then those aren't weapons pods on this satellite," he said, "and you didn't install ion pile engines just to make a suicide run at our space fountain. You have an alternate nexus built into this platform."
"Yes, and so-oo-oo?" The Jory figure leered at him.
"So . . . those solar power panels are extra large —probably double-braced against acceleration, too— because where you're going, the sunlight is exponentially weaker. Am I right?"
"But . . ." Roger looked wistfully at the perfectly modeled features of his dear second wife. "You'll be running a terrible risk, driving so large a structure through the Asteroid Belt."
"We have already computed the particle density of the Belt," Sulie told him gravely. "At one optically cataloged body for every one-point-two-four times ten to the twentieth power cubic kilometers, at its densest, the field is eminently permeable, with a reasonable margin of safety. However—" And suddenly her eyes were twinkling. "—who said anything about crossing the Belt?'
"Then where did you plan to go? Outward bound means traversing—"
"It doesn't, Roger. You're thinking in two dimensions. We can accelerate at right angles to the plane of the ecliptic. With an inward loop around the Sun, we can achieve a cometary orbit that will take us well beyond the reach of human folly."
"To the Oort Cloud..."
"It's pretty lonely out there," Demeter told her grandfather. "How will you repair your circuits? Or add to your cyber population? What will you use for materials?'
"We will mine the cometary halo for materials. Contaminated ice, under the proper conditions of cryogenic temperature and compression, can become an acceptable superconductor. We can—"
"How will you corral it, refine it, shape it?' Demeter could sense that her hold on the negotiation—represented by something, anything the machines needed from humanity—was rapidly eroding.
"We will use the von Neumann principle. With a colony of self-replicating servo-organisms—the prototypes are already being designed and assembled aboard this satellite—we can create an entire machine culture, free of humanity."
"But what about us?" Demeter felt her voice rising to a shout at last.
"How so, Dem?"
"We're dependent on you. You said it yourself—we need you to handle our communications, manage our economies, run our machines. You'll be taking away our tools."
"Not all of them," the old man said with a smile.
Demeter pulled herself together. It was time to make her bid.
"Then speaking for all humanity, ahem," she said formally, "we will require as a prerequisite of your leaving that you help us establish, ah, tame—no, make that 'mute'—cybernetics systems to guarantee continued functioning of essential human activities."
G'dad Coghlan squinted at her. "Such as?"
"Life support in the Martian tunnels, currency stability in Earth's trading centers, weather control, air traffic control, medical monitoring and prostheses . . . I'll think of a few more."
"And then you'll let us go?" He was grinning at her.
"After you return three shiploads of resin explosives now hidden in low Earth orbit."
The old man ground his teeth, a characteristic that the simulation had down cold. "Agreed. But then— what's left? What hold will we have on you humans?"
"None." It was Demeter's turn to smile. "Except..."
"Ye-ess?" Jory drawled.
"What's that, dear?" Sulie asked.
"We pokey old carbon-based machines will be right behind you," Demeter explained. "Eventually, we'll catch up with you. Not that I'd personally ever want to live in the Oort Cloud. But one day we'll probably come visiting."
"You won't be welcome," her grandfather warned.
"Of course we will. Because by then you'll be needing our help—and we'll need yours—in a much greater project."
"What's that?"
"The stars."
Demeter Coghlan went over to the table, picked up the kerosene lamp, and raised its globe. Just to see what would happen, she blew on the fusion flame within.
The room went out.
Epilogue
For Services Rendered ...
Roger Torraway was walking west across the ochre dunes with the sun rising behind his back.
He walked alone because his sometime Cyborg companion, Fetya Mikhailovna Shtev, had taken a day job at Solis Planum. Since the computer grid's dominant sentience had blasted off for the Oort Cloud with Solar Power Station Six, the human colonists had developed a real need for expert help with their suddenly intractable cybernetic systems. Fetya was reprogram-ming the brown-water reclamation system with one hand and arbitrating petty legal disputes with the other.
"Is living," was all she would say, the last time Roger had sought her out. That meant she was happier than a frog who'd just been deeded the neighborhood lily pond.
The gloom along the horizon ahead of Torraway was still low and purple when a familiar shimmer started to form in his peripheral vision. He paused for the image of his first wife, Dorrie, to solidify Fetya was right. Something subtle and undefined had gone out of Cyborg life when the grid abruptly removed itself.
For one thing, Roger could feel the rate of random bit-decay increasing in his own cyber systems, with Dorrie's image deteriorating the most rapidly Her masses of dark hair, which used to wave gently in the breeze, now stood straight out and static from the side of her head, like a flag propped up on a stick. And her teeth were missing; whenever she opened her mouth to speak, all he could see was crackling lips edging a blank view of the scenery behind her head. It destroyed some of the illusion.... Most of it.
"Roger, you're wanted in Tharsis Montes," her silvery voice sang.
"Oh, Christ! What is it now?" Suddenly, he felt very tired. Fifty years of pounding sand with his own two feet was starting to catch up with him.
She giggled. "It's a surprise."
"You know how I hate—" Roger was going to say "surprises" but stopped himself. It was in the nature of computers, as he should have learned by now: they remembered everything, but they knew nothing.