The power satellite that provided the community of Tharsis Montes and its various machinery, including the space fountain, with 7,000 megawatts of electric energy rode in areosynchronous orbit some 500 kilometers east of the settlement. That was as close as it could get. As the simulation's artificially intelligent host explained, it was unsafe to position the satellite any closer because of the necessity of providing clearance with the elevator's upper transfer station. Neither object was ever likely to shift in orbit, to be sure. Still, the fountain required a broad fairway for the passage of ships entering and leaving its domain. The solar collector duly compensated for this eastward offset by angling its microwave beam westward; the rectenna field that was its target was somewhat closer to the tunnel complex.
Demeter Coghlan found herself nodding, closing her eyes briefly inside the goggles as she tried to absorb all these dry mechanics. They were an inescapable part of the simulations introductory narration. The visuals the AI presented during its speech were the builders original schematics, and not at all layman-friendly. They were littered with dotted lines to show the relevant angles and vectors of orbit, dimensions scaled in with arrows and numbers, and color coding that indicated energy flows, structural stresses, and thermal buildup—all quite overwhelming. The tour had obviously been set up for engineers.
After putting her proposition before Ellen Sorbel, Demeter had the rest of the morning free. She had decided to take the programmer up on her earlier suggestion to visit the offworld satellites. Ellen probably found all this technical stuff fascinating. Demeter didn't, but she listened gamely as, in the course of the next fifteen minutes, the machine's pedantic voice explained that, at Mars's greater distance from the sun, the solar cells had to be roughly twice the size of those circling Earth to provide the same energy output. To achieve Station Four's 7.58 gigawatts, average over the daily orbit, the station's area of exposed semiconductor totaled some 210 square kilometers. Magnetic thrusters kept this vast expanse of polymorphic silicon aligned on the sun with a deviance of only one-half second of arc. The diode net of the microwave-receiving station on the Martian surface spread over an area of one hundred and thirty kilometers, with power conditioners spaced every—
"Um, excuse me?" Demeter spoke up.
"Yes?" the AI replied after a pause.
"Could we slap the electronics lesson and go see this thing?"
"Your understanding of the scale of the station would not be complete without—"
"I know all that. But I'd really like to take in the sights before I have to put in another quarter."
'"Put in a... quarter?'" the machine repeated, mystified. "There is no such unit—"
"Just wire me into the nearest proxy and keep your database to yourself, hear?"
"As you wish."
The black background inside her goggles, representing the void surrounding the computerized construct of the station in abstract, suddenly glittered with stars. On the periphery of her vision, sand-colored Phobos tumbled slowly past.
Demeter looked down. Her hands were no longer bone-and-blood hands in the V/R gloves. They had become what passed for manipulators with diis proxy, and they were methodically walking up a ladder. Instead of fingers, the hands used parallel gripping surfaces which opened and closed with a barrel-screw drive, like an old-style Crescent wrench. These keyed into square holes bisected by a bar of sturdy metal. The holes—the rungs of the ladder—were aligned along the outside of a tube about two meters in diameter. Demeter let her gaze rise from this near view of continuous, repetitive motion up the tube . . . and up . . . and...
She almost lost her balance—at least, part of her did, the part that was sitting in the flesh on her chair in the Golden Lotus's simulation parlor. The prow never swerved from its obstinate, mechanical climb. The tube it climbed seemed to stretch to infinity, sloping away from her Eke the curve of the horizon, leaving her with an endless number of steps to negotiate, ascending forever.
Demeter took a stern hold on her stomach and looked away for some relief.
Off to her left, a field of gold blossomed in her goggles. The image flared with reflected light, then dimmed as the proxy's video chips bumped the signal down a few steps. When her goggles had stabilized, Demeter could see that the field was an array of solar cells, as blue as Earth's upper atmosphere. The glare came from their spiderwork of wire cathodes momentarily catching the distant sun.
The solar cells appeared to be massive hexagons, each perhaps a kilometer from point to point. It was hard to tell, exactly, because Demeter was seeing them almost edge on, from a totally flattened perspective. She could only approximate their outline from the angle of the various borders that stretched away from her single point of view, dark blue against the black of space. The AI narration would probably have something to say about hexagons being the simplest shape for tiling such a large area.
Demeter looked back up the tube: more infinity, with stars.
She looked off toward the right, and saw more flattened hexagons.
She tried looking down, toward wherever the proxy had come from in its climb, but the sensor head would not swivel that far.
After another fifty steps or so—each with its complicated slot-grip-and-pull gait—Demeter decided this was boring.
"Um, Narrator?"
"Yes, Miz Coghlan?"
"What is this proxy used for when it's not piggybacking tourists?"
"This unit is a maintenance robot. It is assigned to walk the satellites support spars and inspect for meteor damage to the cell's visible surfaces. It performs this function by interpolation of the—"
"Thank you. Now, do you have any proxies that, oh, fly around and fix things? Is there anything interesting like that for me to see?"
"Maintenance operations are carried out only in the event that actual damage is detected. Of course, we do have an interesting presentation, which—"
"No, thank you. Urn ... this is a completed and fully functioning power satellite, isn't it?"
"Solar Power Station Four went into pre-startup operation on December 19, 2039. It attained full power on—"
"All right, all right. But you've got a station still under construction, don't you?" Demeter remembered something else Sorbel had told her. "Over Schiaparelli, isn't it?"
"That would be Station Six."
"Do you have any proxies there I could look in on? It would be interesting to see your orbital construction techniques."
"No tourist proxies are currently installed on that project."
"Well, could you plug me into a worker robot? I'll accept visual signals only. I wouldn't want to mess up its routines."
"I will see what feeds are available," the AI said primly.
The image in her goggles clicked through a brief spurt of static, and Demeter found herself at the center of a bouquet of arms. They were all jointed in two or more places, waving up around her sensor head like the stamens of a flower. Some had gripper claws holding pieces of irregularly shaped metal and moving them into position; others ended in tools like arc-welding probes and pop-riveting rams, which sequentially zipped and hammered the panels into the wall two meters in front of Demeter's face.
This scene didn't look anything like the vast planes of the other power station, filled with darkly glimmering hexagonal cells crisscrossed by silvery wires. The metal pieces here were all bluntly curved and—from what she saw when one was being turned away from her— all several centimeters thick. Plate steel, Demeter guessed, but the color where the arc touched it was strange, purplish. Maybe some kind of alloy?