Corrie frowned at the blank display screen. “We can pick up anything down to a second of arc with that set of cameras. And I just checked the pointing, it’s straight at Atlantis. I’ll bet that Regulo and Morel are playing games with the albedo again. There’s a variable reflectance material on the outside of Atlantis, so they can absorb solar radiation selectively, with just the ranges of wavelengths that are best for the interior. You might try taking a look in the thermal infra-red.”
Rob raised his eyebrows. “I’ll try. But I thought those variable albedo materials were still text-book. It’s a fancy technology. Let me see what we get with the ten to fourteen micrometer scanner. The resolution won’t be as good, but maybe we’ll pick up some sort of blob.”
He switched the channel selector, while Corrie leaned over his shoulder. “Regulo doesn’t let things stay in the text-books,” she said. “If there’s any way it can be transformed into a piece of hardware, he’ll do it. He was asking me the other day if you could make the Spider extrude materials at high temperature. I don’t know what he was after, but I suspect that you’ll find out when we get to Atlantis.”
“He asked me that, too.” Rob was tinkering with the fine tuning of the screen display. “It’s just a question of using the right materials for the extrusion nozzles — easy enough. Ah, there we are.” They stared at the screen, where a small, fuzzy ellipse had appeared.
“That can’t be it,” objected Corrie. “The picture we get ought to show a sphere.”
“It would, in the visible part of the spectrum. We’re looking at it in the thermal infra-red, remember, so we’re seeing differential heat emission from different sides. Atlantis must be rotating, with the side facing away from the Sun always a bit cooler. That’s why it looks lop-sided.” Rob was peering with interest at the display of the asteroid. “Two kilometers across, eh? What do you think Regulo would charge to make one like that for somebody else?”
“Price isn’t the issue. He couldn’t do it.” Corrie saw his skeptical look. “Honestly. It’s not that he wants the only one — though I suspect that he does. This one was a fluke. There will never be another like it.”
“Never is a long time. Why do you think it’s one of a kind?”
“Judge for yourself when we get there. Regulo found this about thirty-five years ago, when they were doing his first complete survey of the Belt. Nobody else realized the significance of the find, so he got the rights to it for almost nothing. Most people thought it was useless — who could use something with that composition? All the outside was water ice, more than you’d ever need for the volatiles of an orbit adjustment. There was a lump of metallic ores — very pure — sitting right in the middle, but it would be difficult to reach.”
“You mean it wouldn’t pay to tunnel in and mine it? I suppose not. There are plenty of other candidates around, with more ore and less water.”
“That’s what the other miners decided. But after he bought long-term rights, Regulo coated the outside with a black hi-temp plastic, started it rotating, and dropped it into a tight hyperbolic. Then he picked it up on the other side, once it was well clear of the Sun.”
Rob was busy at the calculator interface. After a few seconds he looked up and shook his head. “It wouldn’t work, according to me. You’d never melt it with a single fly-by.”
“Did I say that? He had his team pick it up near Mercury and put it into a Trojan orbit with the planet. He wouldn’t go near it himself, of course, not that close to the Sun. While the meltdown was going on he had a mining group confirm the first assay of the ores and do the core analysis in more detail. That became a lot easier after partial melt. It took five years to complete the change from ice to water, then they used some water in the drives to take it further out. Regulo met them near Earth and started the installation of the hydroponics systems. By that time, some of the others had begun to get an idea what he was doing.”
“And now he has it self-supporting?”
“Completely. Regulo says that with a few months’ warning Atlantis could survive if Sol went nova. He’d simply move the whole thing out to a safe range from the Sun.”
“But he’s exaggerating.”
“Of course he is.” Corrie laughed, throwing her head back. As she did so. Rob was distracted by her sudden resemblance to Senta Plessey. Would he be able to help Howard Anson with Senta, after this trip to Atlantis?
“But he’s entitled to exaggerate a bit,” Corrie went on, and Rob pulled his attention back to her. “He’s rather proud of that job,” she said. “He claims that he’s the only person in the whole System who would have thought of it.”
She looked at Rob, head cocked to one side. “You know, you two are alike in another way. Each of you is convinced that he’s the only smart person in the System.”
“Universe. Whereas?”
“Whereas Caliban is a lot smarter than both of you put together.” Corrie was laughing. “Smarter than Joseph Morel, too.”
“Caliban? Who the devil is Caliban?”
“You mean Regulo hasn’t told you? Then you have another treat coming. Just wait and see.”
She was in an unusually cheerful and fickle mood. That was all the response that Rob could get. She replied to all his questions with cryptic, evasive answers, while the cruiser bore them steadily closer to Atlantis.
Rob remained peering into the scope, seeking more details of the mystery asteroid ahead. Following Regulo’s work, it had become a sphere of water rather less than two kilometers across. It was surrounded by a restraining membrane of tough flexible plastic, a trapping surface for solar heat. The aquasphere was pierced by twenty metal-lined shafts that served as structural braces and also provided access from the exterior of the asteroid to the central metal sphere where living quarters and laboratories were located. Other entry to the two-hundred-meter central biosphere came from the ports that connected the living quarters to the aquasphere. As they drew closer, Rob could see the silver gleam of heavy drive equipment positioned near the outer edge of each entry shaft. The whole ponderous assembly was rotating slowly about its center of mass. Small attitude jets positioned at a number of points on the surface showed how the rotation rate was controlled.
“I thought you were just joking about getting away from a nova,” said Rob. “Now, I’m not so sure. There are drives all over that thing and they look like big ones. Do you know what sort of acceleration he can get on it?”
Corrie was busy at the communicator, tuning in for their final arrival. “Not much at all,” she said. “There’s plenty of power, but the limiting factor is the strength of the support shafts and the surface membrane around the aquasphere. They take the main stresses when Atlantis is accelerated. The interior is nearly all liquid water, even allowing for the support shafts and interior structures. You need monster drives for any acceleration worth speaking of, because Atlantis masses about four billion tons. That takes some shifting. Regulo usually doesn’t try for more than a hundredth of a gee. He gets around, but it takes a while.”
They were creeping closer to one of the entry shafts, their angular rate matching to that of the asteroid. Close up, the surface had a dull, smooth finish, making Atlantis visible only as a black mass occulting the bright star field behind it.
“No wonder I couldn’t pick it up on the screen,” said Rob. “The surface is sitting there in full sunlight but there’s no radiation back-scatter at all. At least, there’s not enough to see.”
“There should be hardly anything at visible wavelengths.” Corrie was sitting next to him as they awaited final docking. “Morel designed it that way. The aquasphere has been made into a self-sustaining community of plants and animals. It uses all the light that it can get for photosynthesis. That’s why Regulo and Morel covered it with variable albedo materials. Nothing is reflected as visible light, and all the heat goes out through the side facing away from the Sun.”
“Sounds like a violation of the Second Law of Thermodynamics to me.” Rob was
impatiently peering out of the side port, waiting for a glimpse of the interior. “You’re telling me I won’t be able to see anything at all from out here, then?”
“That’s right. Wait until we get inside, then you’ll see plenty. You can even take a swim through the interior if you want to.” She grinned at some secret joke. “I somehow doubt that you will. I certainly never have. I should have warned you of one other thing: be prepared for a fishy dinner. Regulo imports food when he feels like it, but he makes the point to new arrivals that he has a completely closed ecology operating in Atlantis. The human living quarters in the center are part of the overall balance, with reprocessed wastes going back into the aquasphere as nutrients. Of course, you lose a little mass when you move around the System, but Regulo replaces that occasionally from other asteroids.”
“Does Atlantis have any internal power sources? Big ones, I mean, to provide power and light.”
“There are a couple of fusion plants, and Regulo talks of adding a power kernel. Why?”
“I was thinking of your statement that Regulo hates the Sun. With this set-up, he’s independent of it. He could provide the light for photosynthesis in the aquasphere from his own power sources, and if he did that he could go as far away from the center of the System as he chose — out beyond the Halo, if he feels like it.”
“He’s talked of it; but he likes to know what research is going on, in the Belt and back on Earth. If it weren’t for that, I think he might take Atlantis a long way out. Maybe leave the System completely.” There was a slight bump, felt through the floor of the ship. “Feel that? We’re docked. We can go inside now. Regulo doesn’t believe in elaborate entry procedures. Anybody that he doesn’t want in Atlantis would never get this far. His computers will have checked the signature of this ship against the System ship listings when we were still a hundred thousand kilometers out.”
She stood up and led the way out of the main cabin and through the lock. The rotation rate of Atlantis was low, barely enough to give a feeling of weight. The ship had docked at the exterior surface of the asteroid, on the “equator” farthest from the axis of rotation of the sphere. A flexible umbilical led to the entry shaft. It had been attached automatically as the ship docked. As they passed into the main shaft, baffles sealed it behind them. Within thirty seconds the atmosphere in the interior was up to half a standard atmosphere, oxygen-rich and matched to that of the ship they had just left. Rob followed Corrie as she pulled herself easily along the broad, dark tunnel that led to the central metal sphere. About halfway along they halted at a second lock and removed their suits. Once they were ready to go on, Corrie led Rob to the side of the tube.
“I think I can show you something to match your Coal Moles,” she said. “You know, Morel and Regulo built a complete water-world here, and this is one of the viewing ports. You’ll find the same sort of thing all over the inner sphere. Take a look through there.”
She pointed to a transparent panel about two meters across set into the side of the lock chamber. Rob went to it and looked out. It took a few seconds to become accustomed to the scale and distance of what he was seeing. Then he grunted with surprise and leaned closer to the panel.
The water that filled the interior of Atlantis was very clear. He could see for at least a hundred meters into a green, shady interior, filled with huge and abundant plant growth. It clustered around a complex supporting grid in the form of a symmetrical series of spherical frames, like concentric shells. Between the spheres of vegetation, far away into the dim light, moving shapes were faintly visible. In rainbow colors, they turned, darted, or cruised lazily among the curtains of floating plant life. At the limit of vision, Rob fancied that he could see the phantom outline of something much bigger, a dark irregular shape outlined against the lighter green-blue background. As he watched, it drifted farther off and merged into the fronded luxuriant weeds.
He turned back to Corrie. “That looks like a fresh-water ecology out there, but I could swear that I’m seeing forms that only live in salt water back on Earth. Is it fresh, salt, or what?”
“It’s all fresh water. There was no easy way to find a mass of salt where and when they wanted it. They discovered salt deposits later on some of the asteroids, but by that time they were committed to most of the biological forms.” Corrie again began to lead the way toward the central structure. “You’re quite right about the mixture of life-forms. That has been one of Morel’s interests. Over the past twenty-five years he has been developing marine animals that can stand the transition from salt water to fresh. You’ll see how successful he has been when you have an opportunity to examine the aquasphere. It wasn’t an easy problem. Morel had to do a good deal of genetic engineering before he was satisfied with most of them.”
They had reached the final hatch that marked the end of the entry shaft. She led the way through.
“I’ll take you as far as Regulo’s office, then I’m supposed to go and meet Morel in the bio section. I’ll see you later on, when we eat. It’s a good bet that Regulo will have an elaborate meal planned. He likes to show off the latest from the sea-farms. It can’t compete with Way Down, but I think you’ll be impressed.”
She continued along the curving corridor that followed the outer wall of the central living sphere. Rob followed, noting that there was scarcely enough gravity to give his feet useful contact with the smooth floor. He copied her example, using his hands on the ridged side walls to propel himself along.
At a big sliding door set into the left-hand wall of the passage, Corrie paused. “Here you are. He’s inside. Have fun with your boy toys, and I’ll see the two of you at dinner.”
She went on her way along the corridor. After a moment’s hesitation, Rob reached out and touched his hand to the door control.
CHAPTER 7: How to Build a Beanstalk
Either Regulo had somehow furnished the study with exactly the fittings that Rob had seen in the room where Rob first met him, or he took the whole thing with him from place to place. There was no mistaking the curious pink-topped desk, with its flanking wall displays, video cameras and output terminals. The dark red carpet was the same, and the internal lighting was held to its familiar subdued level. Only the gravity was noticeably different, lower here than at the station in Earth orbit. Atlantis could not tolerate the rotation rate that significant centrifugal gravity would require.
Regulo was seated behind the big desk. He watched while Rob stared around him, reading his reaction.
“You see, now, I’m no better than a tortoise,” he said. “I carry my house about on my back. Costs a little, but it’s worth it for the convenience. Old dogs don’t like new kennels. Come on in and sit down, Merlin. Welcome to Atlantis.”
Rob moved to the chair that the old man indicated. His weight on the seat was barely perceptible, no more than a fraction of a kilogram. He looked at Regulo, shocked again by the sight of the ravaged face with its seamed and corroded features. Then he pushed that thought to the back of his mind. Regulo had a big pile of documents sitting in front of him, and a curious expression of suppressed glee shone in his bright eyes.
“Got your work on the beanstalk design,” he said gruffly. “Ready to talk about it, or do you need time to settle down?”
Apparently Regulo didn’t intend to indulge in social patter about the length of the trip from Earth. That suited Rob. He wanted to get to the real meeting as much as Regulo. He nodded. “I’m ready.”
“Good.” Regulo patted the stack of materials in front of him. “I pulled my old work out of the files. All done a long time ago, back before we could even mass-produce high-load graphite whiskers, never mind the doped silicon stuff that we’ve got now. You’ll see it soon enough” — Rob was leaning forward in the seat — “but first I’d like to hear what you have to say. Do you think you could build me a beanstalk?”
“I can build it.” Rob’s voice was confident as he pulled out his own design notes. “That’s the least of my worries. First of all, I c
an speed up the Spider. Two hundred kilometers a day of extruded cable will be no problem; maybe we can do a bit more than that. I can make it work with doped silicon instead of graphite, that’s a minor change. That gives us a load-bearing cable that can take over two hundred million newtons per square centimeter. I used a design diameter of two meters for the bottom end, but you can make that any value you choose. There will be a little bit of a taper as you go up, but it’s very small. The cable is only five percent thicker at geosynchronous altitude than it is at the ground tether.”
Regulo was nodding, his eyes fixed on Rob’s. “What load will it take with that diameter?”
“More than I ever see us needing. About two-thirds of a billion tons at the bottom end. I wouldn’t expect that you’d ever want to haul anything more than a few hundred thousand tons up to orbit at one time, or bring it down to Earth. Actually, I can’t see us needing even a tenth of that, but I’m following your advice and thinking big.”
Darius Regulo was nodding happily, drinking in Rob’s words and numbers. He was in his element. “I started out my design with a one-meter base diameter when I did it. Either way, it ought to give us more capacity than we’ll expect to use; but I’ve found that whenever you build in a capacity, you somehow get to use it.” His eyes seemed to capture and focus the dim light of the room, shining cat-like at Rob through the gloom. “So far, our thinking matches. What problems have you found?”
“Four main ones. Only two of them are really engineering.” Rob consulted his notes, then leaned back and began to tick off points on his fingers. “First of all, where do you construct it? The obvious way would be to start out at synchronous orbit and extrude cable up and down simultaneously, so you keep a balance between the cable above and below you, with gravity and centrifugal forces matching.
The Web Between the Worlds Page 10
