They took the subway car from below the apartments to the basement level of the Berlin spoke, at which point the car locked into vertical drive to become an elevator. A few minutes after leaving, they emerged into the "Berlin Line" concourse at the Hub. Moving in a slow-motion ballet at four percent of normal gravity, they took the south exit and climbed toward the Spindle along a corridor whose floor curved upward in a series of shallow steps that became progressively shorter until the corridor had transformed itself into a broad staircase. Using the skill that all inhabitants of Janus had quickly learned, they ascended the stairs in a smooth gliding motion that required only occasional pushes with the feet and corrective nudges on the hand-rails to sustain momentum.
Section 17D was located in the outermost layer of the Hub facing south, some distance below part of the circle formed by the intersection of the Hub sphere with the three-hundred-foot-diameter cylinder of the Spindle. They found Solinsky in an untidy enclosure at the back of the miniature maze of partitioned offices and storerooms that formed the Maintenance & Spares Unit. Despite the fact that Janus had been operational for only a matter of months, the place already looked the way that all supplies and stores offices somehow should, with oily fingerprints on the consoles, disorderly piles of notes and requisitions strewn all over cigarette-burned desktops beneath magnetic paperweights, and stained reference charts competing with gaudy pin-ups for wallpaper.
Solinsky slipped the K56 to Chris, who put it in his pocket without either of them mentioning it.
"Say, who's the friend?" Solinsky greeted with a broad smile. "Is this somebody else out of the Egghead Block that I never saw before?"
"That's right," Chris said. "This is Kim. She's from CUNY too. Kim, this is Mat. He's an almost civilized mutation of the American species."
"Hi," Solinsky grinned as he and Kim shook hands. "Wow! Some egghead. How do I get a transfer to computers?"
Kim smiled back. "I wouldn't recommend it, Mat. You have to put up with too many insufferable Englishmen. You're better off staying in the Army where they can't get in."
"Aw, I'm not so sure," Solinsky replied. "I reckon I could stand it." He transferred his gaze to Ron, who was surreptitiously admiring some of the pin-ups. "How's it going, Ron? Still making time with that broad from Vine County?"
Ron screwed up his face and shook his head. "Nope. I got outgunned and sunk by some crewcut hero from the Navy. You know how it goes . . . But you oughta see her roommate—radar op in E5. Now she's what I call really nice."
"Is that the one who was with you in the bar last night?" Kim asked. "The one who was talking with you and Ray . . . dark hair and green pants?"
"That's her," Ron answered. "Not bad, eh?"
"You want to watch it," Chris warned. "You could end up getting sunk again. You know what months away from home does to these chiefs."
"No chance," Ron retorted. "Ray's got other interests. He's—" Even as he spoke, the almost imperceptible hardening of Kim's features told him he had said the wrong thing. Solinsky sensed the tension and stepped in to change the subject.
"I haven't offered the grand tour," he said. "Every new visitor to the M & S Unit gets the grand tour. You people got a few minutes?"
"What's the grand tour?" Kim asked.
"It's what I was telling you about," Chris said. "It's good. You wait and see."
Solinsky led the way through a door at the rear of the unit and into a large room full of rows of racks and storage bins. They left through another door which brought them out onto a long walkway, running along the wall to either side and protected by a metal guardrail. The walkway looked down over a work area where several figures were busy around two beetlelike vehicles standing side by side on tripod undercarts. They were about fifteen feet long, roughly box-shaped with lots of protruding gadgetry and struts, and each was equipped with an array of external manipulator arms at its forward end. Immediately in front of the vehicles were two inner airlock doors above which the walkway continued horizontally, at the same time curving around to form a viewing platform behind the long window that made up part of the outer wall. Chris and Ron had seen it before. Kim gasped in amazement but said nothing as she followed the others in a series of slow, shallow bounds along the walkway to where it widened out, above the airlocks and immediately behind the window.
Even in the minuscule gravity there was still a remnant sense that enabled her to distinguish up from down. They were looking along the outside surface of the Spindle toward Detroit. The enormous sweep of the three-hundred-foot-diameter cylinder disappeared from view above their heads to meet with the Hub at some unseen point beyond their field of vision. The Spindle extended away for over five hundred feet and then vanished abruptly into the immense metallic sphere of Detroit, swelling outward more than a tenth of a mile from the Spindle to blot out all but a thin crescent of star-speckled blackness to one side. A little short of halfway between where they were standing and the northern extremity of Detroit, two raised, parallel lips ran around the surface of the Spindle and disappeared out of sight behind its curve in both directions to mark the ring of the Spin Decoupler system—the point at which the rotating structure that comprised the North Spindle, Hub and Rim joined the nonrotating assembly of South Spindle, Detroit and Pittsburgh.
Kim watched in mute fascination as the massive ribs of the Decoupler ring slid smoothly past one another at ten miles per hour. Her senses told her that she was stationary while Detroit and the rest of South Spindle were turning along with the background of stars, but she knew that in reality it was she and the part of Janus that lay north of the Spin Decoupler that were turning at a little under one revolution every minute. The huge solar dish that formed part of Detroit came slowly into view from beneath the Spindle, reached the bottom point of its plunge and was carried up and away out of sight again behind the curve of Detroit. Soon afterward it was followed by the far larger bulk of the half-mile-square Radiator Assembly projecting from Detroit diametrically opposite the solar dish, which passed them edge-on and extended away beyond the limit of the window's viewing angle.
"Quite a sight, isn't it," Chris said at last. "After you've been cooped up in the Rim for a while, you begin to forget that Janus has got an outside to it. It makes you feel like a maggot that's just poked its head outside its apple for the first time, doesn't it."
"I've never really appreciated the perspective before," Kim murmured. "I saw it on the screen inside the shuttle when we came up and I've seen enough models and pictures, but seeing it for real close-up . . ." She shook her head as her voice trailed away.
"That's the Spin Decoupler," Ron said, pointing.
"One of the most critical parts of Janus," Solinsky added. "Can you imagine what would happen if that were to jam up suddenly?"
"What?" Kim asked him. "I'm a computer researcher, not an engineer."
"Well, the whole of the Hub and the Rim are going around together," Ron said. "With the mass of the Rim at a distance of three-quarters of a mile out from the axis, that's one hell of a lot of angular momentum. That says you don't stop it just like that. It'd be like a big clutch snatching all of a sudden."
"So what would it do?" Kim asked. "Start taking Detroit and the rest around with it? That'd be a pretty big jolt."
Solinsky grinned and shook his head.
"It'd be pretty big all right. There's a helluva lot of inertia in Detroit and Pittsburgh out there. You don't start them moving just like that either." He made a snapping motion in the air with his hands. "No ma'am. If that Decoupler ever locked up, the Rim and Hub would wrench itself clean off. You'd bust Janus clear in half, just like a dried-up ol' twig."
Kim looked at him in amazement and was about to reply when one of the figures on the floor below launched himself vertically with an effortless push of his legs and sailed upward to the walkway where he caught the guardrail to turn his flight into a slow vault that brought him standing beside them.
"Are these the people who wanted to go outside?" he asked, looking at Solinsky.
"That's right," Solinsky answered. "I said two but it looks like it's three. I don't figure you'll be doing much complaining about the extra one though." He turned and grinned.
"Remember that trip outside that you asked about at Vokes? I've been keeping a little surprise for ya. I've fixed it. This is Mitch. He'll take you along on a routine check of the dishes that's scheduled for about now. You ready to go, Mitch?"
"All set," Mitch replied. "We're using Isabelle." He gestured toward the nearer of the two bugs. "There's still a fault registering in Maisie's starboard retro. Dave and Bud are looking into it."
"That's okay." Solinsky beamed at his three guests. "There you go then, folks. What d'you say? A free trip around the lighthouse?"
Ron and Chris were already nodding enthusiastically.
Kim looked despairingly from one to the other and sighed. "I don't know. Whenever I get mixed up with you guys, I always let myself in for something crazy, Okay, let's go. We can't turn it down now that we're here . . . not after Mat's been through all the trouble to fix it up."
"That's the idea," Solinsky said approvingly. Mitch turned back toward the rail.
"Okay," he called over his shoulder. "This way." With that he reversed his vaulting trick and sailed back to the floor below. The other three looked at one another.
"Ladies first, I was always brought up to say," Chris insisted cheerfully. Kim flashed him a murderous look, stepped forward, hoisted herself over the rail with an easy flick of her wrist, let go, and proceeded to hang for a moment before starting to drift downward with agonizing slowness.
"You'll take all day if you do it like that," Solinsky laughed, leaning over the rail. "You have to give yourself a push down." He held the rail with one hand and shoved gently but firmly against the top of Kim's head with the other. Kim squealed and disappeared below the walkway to land beside Mitch a second later. Chris followed with a neat imitation of Mitch's performance. Ron pushed off too hard and sailed out of reach of the handrail. He hung in the air shouting obscenities and then drifted slowly down like a punctured balloon to join the amused semicircle below.
Five minutes later they were securely strapped into the seats of the bug's tiny cabin amid a confusion of instrument panels and controls that seemed to sprout like weeds from every available chink of space. Mitch ran smoothly through the cockpit drill, checked with Control via radio and announced that they were cleared to go. The inner doors of the airlock in front of them slid aside and the bug rolled forward.
"Manual control?" Chris asked in surprise as he watched Mitch in the seat next to him. "I thought everything on Janus was supposed to be tomorrow today."
"Maintenance vehicles are manual," Mitch told him. "It wouldn't do if you had to rely on something that might turn out to be the thing that needs to be fixed. It's like it's handy to have an oil lamp around in case you ever have to fix the lights."
The doors closed behind them and the lock emptied. Then the outer doors opened to reveal again the spectacle of Detroit swinging slowly by at the far end of the enormous expanse of the Spindle. The bug slid forward and the floor of the lock fell away behind.
They were climbing away from the immense sphere upon which the entrance to the lock was just a diminishing spot. It was like a speeded-up replay of a view picked up from a climbing moonship. Detroit and the Hub swung around in perspective and became the two ends of a huge dumbbell that was beginning to take shape against an infinite cosmic backdrop. And then, as they pulled clear of the obscuring edge of the Hub, the full majesty of the Rim opened up beyond, shining brilliantly with reflected sunlight along its full circle and six gigantic spokes. Between the concentric circles of the Rim and the secondary reflectors, they could see the ghostly outline of the mile-wide primary mirror hanging even farther away in the void beyond, visible only by virtue of the stray light from the solar corona that leaked past the focal boundary of the secondary ring. It was a phantom ellipse of ghostly radiance floating against the blackness of space.
Mitch brought the bug over so that the Spindle was below them. Detroit was now a smooth mountain rearing high above their heads in front. The bug moved toward it and followed its contour upward. As they came over the crest, the sweeping curve of Detroit fell away below to uncover the second mountain of Pittsburgh at the far end of the Spindle.
"I feel like a fly on an elephant's arse," Chris remarked absently.
As they came over the top of Detroit, Mitch held height and set a direct line to graze the summit of Pittsburgh. The south slope of Detroit fell away beneath and the Spindle became the distant bottom of a trough between two enormous frozen waves of metal. Now they had a true feeling of being alone in their fragile capsule with the vastness of space stretching away in every direction. Earth was visible on the far side of Janus, framed on three sides by the Spindle and the twin arcs of Detroit and Pittsburgh while on the side of them away from Janus, standing alone amid millions of miles of emptiness to hold the darkness and the cold at bay, blazed the brilliant white orb of the Sun.
They cleared Pittsburgh and descended, finally rounding the end of the Spindle to watch a catcher ship just in from Luna docking at Southport. Mitch completed the inspections that had been scheduled and then took them out to return to the Hub along a wide curving path that carried them two miles out. From there they could see the whole structure of Janus looking just as it had in the 3D image they had seen for the first time not very long before in a lecture room somewhere in Virginia. But this time Janus was real, and Virginia was a long, long way away.
As Mitch was making the approach run and the Hub was growing larger ahead of them once again, the passengers remained quiet and their minds slowly absorbed what their eyes had seen. The experience had revealed a whole new dimension to their experience on Janus. The thought-habits of a lifetime all had to be taken to pieces and put back together in strange and unfamiliar ways. One day, no doubt, generations would be born and grow up to form all their concepts of normality in places like Janus—places even vaster and more complex than Janus, where inside and outside became interchanged, up and down were just geometric conventions and gravity changed from place to place.
How would their ideas of normality have to be revised when at last they set foot on the surface of someplace like Earth?
A call on Kim's viewpad sounded suddenly and broke the spell. It was Fred Hayes, calling from one of the consoles in the Crystal Ball Room.
"I know you're off duty, Kim, but I thought you might want to come in," he said. "Things are getting interesting." The atmosphere in the cabin of the bug at once became tense.
"What's happened?" Kim asked.
"There's a big flap going on in the middle of the floor here," Fred informed her. His voice was brittle with suppressed excitement. "We've shut down SP Three via the substation, but Spartacus is still running at one-hundred-percent capacity, just as if it wasn't missing a super-primary node at all! It's functioning normally even after it's had a full lobotomy. Nobody here can figure out how."