He was silent for a moment, reflecting. His face showed no fear or bitterness, only a still introspection. “Always worrying about losing her looks,” he said at last. “That was her biggest fear of all. How is she now? It’s been a long time.”

“Still beautiful.” Rob struggled with this new view of Senta Plessey. One perspective from Howard Anson, one from Corrie, and now this. “Look, Regulo, it isn’t any of my business, but you say that she walked out on you. And you still provide her support?”

That earned a piercing look for Rob from those bright blue eyes. “Now where the devil did you hear that?” Regulo said softly.

“Oh, from a man back on Earth,” Rob felt embarrassment, aware that he had gone beyond the acceptable questions. “I wasn’t trying to pry. It’s just something that I’d heard.”

“It’s true enough.” Regulo’s voice sounded even gruffer than usual. “I knew what Senta’s worries were. We had some good years together, and I wouldn’t let her be miserable for nothing. We both know I’ve got enough money, more than I can ever use, more than Senta realizes. She spends, but I don’t restrain her. Why should I? It’s only money.

“Now, let’s get off that subject.” His voice took on its old, eager tone. “I want to see what you’ve been doing, and I want to show you what we’ve been at. You’ll see why I wanted you up here. Take a look at this.”

He switched on a large holoscreen that ran from floor to ceiling on one side of the study. In it appeared a view of a small asteroid, swimming free in space. Away to one side of it Rob could see a familiar shape. He frowned.

“That’s one of my Spiders. I thought they were supposed to be out in the Belt.”

“That one will be, as soon as the demonstration is finished.” Regulo adjusted the control to zoom in on part of the image, and pointed at the upper part of the screen. “Now, take a look at the top of the rock there.”

“It looks like a drive unit.” Rob reached over and increased the magnification a little further. “There’s another one at the bottom, from the look of it.”

“Quite right. You can’t see this on the image, but the whole rock has been covered with a layer of tungsten fibers. They’ll hold their strength up to nearly three and a half thousand degrees. See anything else near where the Spider is hanging?”

Rob moved the joystick and the magnified area shifted until it was centered on the dark bulk of the Spider. “I can see a housing on the surface of the rock. It looks like a power attachment, without the rest of the powersat.”

“Right again.” Regulo was in his element. “We’ll be hooking a powersat in position four hours from now. The connections have been set up to work with either that or a power kernel, to take electricity from the power source and distribute it around the rock. Now, one more fact and then you’re on your own.” Any pain that Regulo was feeling had been pushed away from his conscious thoughts. His voice was full of a huge satisfaction. “Zoom in on the Spider, and tell me what else you see.”

Rob leaned forward, moving his head from side to side to get a better look at the holo-image. “You’ve done something to the proboscis,” he said at last. “It’s been lengthened, and it has a different reflectivity. Hm. Have you changed the composition?”

“To a high-temperature ceramic.” Regulo nodded. “I ought to brush up on my knowledge of spider anatomy. In my ignorance, I’ve been calling it a sting. All right, we’ve changed the proboscis. It will take very high temperatures, and it’s still flexible. Now you’ve seen everything, so you tell me. What game are we playing here?”

Rob stared at the image in front of him, his imagination hyperactive. Regulo wouldn’t have gone to these lengths unless he had something very real in mind. It was just a question of sorting through all the possibilities and choosing the one with the commercial slant.

“What’s the composition of this rock?” he said suddenly.

“Metals, mostly — several different ones.”

Regulo waited expectantly. After a minute or two more, Rob nodded.

“I see it,” he said. “It all seems feasible, but I’d want to explore the details.”

“Well, man.” Regulo was suddenly impatient. “Come on, tell me how you think it ought to work.”

“All right.” Rob stood up and went closer to the screen. He pointed at the drives in the rock. “Let’s start with these. You set them to provide equal and opposite thrusts, one on each side of the asteroid. You fire them tangential to the surface, and you use their torque to set the rock spinning fast about an axis. The faster, the better, provided that the tungsten sheath around the whole thing can take the strain.”

“No problem at all with a small rock like this. We might have more to worry about when we get to something the size of Lutetia.”

“Let’s finish this one first.” Rob pointed again at the image. “I’ll assume you have the powersat in position by the housing there. You picked that placing so the powersat sits on the axis of rotation of the rock. It would be a messy calculation, but the principles are easy. Now you begin to feed power in to the rock, through a grid over its surface. A lot of power. For something much bigger than this, I don’t think a powersat will do it. You’ll need a fusion plant or a power kernel, otherwise the job will take forever.”

He squinted again at the configuration on the screen. “Are you sure that the rotation will be all right? I’d expect a stability problem. It will be difficult to keep a smooth rotation about a single axis as the shape changes. I assume you looked into that and have the answers?”

Regulo nodded. “I cut my teeth on that sort of problem, calculating the change in mass and moments of inertia as the volatiles boil out of an asteroid during solar swing-by. We’ll have small adjustments to make as we go, but I have those worked out. Keep going.”

“Alternating currents,” Rob said. “Big ones, through the middle of the asteroid. When you apply those from the power source, you’ll get eddy current heating inside the rock from hysteresis effects. If you put enough power into it, you’ll melt the whole thing. You’ll produce a spinning ball of molten metals and rock. Spinning fast. I assume you’ve looked at the shapes and structures for a stable rotation? You’ll want a Maclaurin ellipsoid, with an axis of symmetry, rather than a Jacobi ellipsoid with three unequal axes.”

“You will indeed.” Regulo’s face was intent, his eyes fixed unwinkingly on Rob. “I’ve looked at the stability of the rotating mass. It will be all right. What next?”

“The rotation produces an acceleration gradient inside the rotating ball. The heaviest metals will migrate to the outside, the lightest ones will be forced to lie inside and closest to the axis of spin.” Rob was visualizing the ball, shaping it before him with his hands. “It’s like a big centrifuge, separating out the layers of melted materials. All you need now is the final stage: the Spider. It sits out on the axis of rotation, at the opposite end from the main power source. But it has that long, specialized proboscis, so it can reach any point inside the asteroid. You insert it to the depth that you want, and draw off that layer of rock or metal. Then you extrude it directly through the Spider — I already made the modifications you asked for, to permit high-temp extrusion.”

“You did.” Regulo’s eyes were gleaming. “And we can do away with all that mess that we had to use for the beanstalk. Chernick and the Coal Moles was a neat idea, but it was still a patched-up solution. With direct extrusion we’ll see a terrific improvement in what we can do. Give me access to Lutetia and I’ll spin you a cable from here to Alpha Centauri, with any material in the asteroid. No more grubbing about for different metals. They’ll come pre-sorted by density.”

He grinned at Rob’s expression. “All right, maybe not Alpha Centauri. We could certainly spin a web right through the Solar System, if we can think of a good use for one.”