The view from L-4 was always a surprise to visitors. It was Earth that drew the attention first, looming four times the size of the Moon. The lunar sphere appeared exactly the same size as seen from Earth, but it was the body that finally received the closer look. The markings seemed all wrong. An Earth dweller had that same invariable face planted deep in his memory, back before he could recall any coherent sights. When the familiar face was changed suddenly to an alien profile it became a new and interesting world, no longer Earth’s age-old companion. And that feeling persisted. Rob had made the trip to L-4 many times now, and was becoming accustomed to the new face in the sky. Even so, he found that he was taking an occasional look at the bright hemisphere as he rode slowly along the length of the beanstalk, heading back towards the Spider.
The load-bearing and superconducting cables, along with the elements of the drive ladder, were being extruded as a single complex unit. That was the assembly to be flown in to a landing at Tether Control. The rest — ore and passenger carriers, maintenance robots and condition sensors — would all be added later, once the beanstalk was settled in position.
There had been a slight argument with Regulo on the question of the ore carriers. He had wanted to do it in the same extrusion process, eager to see how much could be done with the Spider. He seemed to regard it as his own new toy. Rob had persuaded him that it would make the fly-in to Earth tether more complicated, even though the extrusion itself was feasible. Addition of the ore carriers would be a separate installation job, by a team ready to work up and down the length of the beanstalk itself, and it could be done in less than a month with maintenance robot assistance.
The doped silicon strands of the load-bearing cable gleamed brightly in the sunlight, a gossamer loop extending out from L-4 and far off towards the distant Earth. Rob could follow it by eye for only the first few kilometers. Beyond that, thousands of tiny sensors planted all the way along its twisting length sent frequent radio inputs to Sycorax’s orbit adjustment programs. The results of those computations were channeled through to Rob and, failing his override, initiated any necessary corrective action on the beanstalk. Small reaction motors, mobile along the length, maintained the delicate overall stability of the vast loop. Regulo had readily accepted Rob’s suggestion that they should use two Spiders, fuse the first few kilometers of cable that each extruded, and generate a long, looped strand that would halve the total time for manufacture. The maneuvers prior to fly-in would be more complicated because of that, but Rob was convinced that they were well under control.
He looked ahead. Far in front of him he could now see the bulk of the asteroid that Regulo had moved in from the Belt. Close to its surface, still invisible to him, floated the two Spiders, endless streams of bright cable squirting from their spinnerets. He was watching for them as he moved steadily closer to the asteroid, until a second small inspection craft, similar to the one that he was riding in, moved away from the shadow of the asteroid and headed in his direction.
“Corrie?”
“Right.” Her voice was clear over the head-set. “I thought I’d come out, meet you, and take a look for myself. How is the beanstalk behaving?”
“So far, as smooth as you could ask.” As Rob moved level with the second ship it turned and began to follow him along the cable. “I rode around the whole loop without seeing anything we need to worry about. There was a little oscillation and twisting at the far end, but it was being damped by the reaction motors by the time I got there. Somebody back there on Atlantis is doing a good job on the control calculations.”
“That’s all Sycorax — maybe with a little help from Caliban.”
“Are you serious? If you are, I’m going to start worrying a little. I don’t think Caliban knows anything at all about computational work.”
Corrie laughed. “I’m not sure if I’m serious or not. Sycorax has become so complicated that not even Regulo and Morel know any longer who is doing what. There are non-deterministic elements built into the computer, and there are real-time linkages built in to the relations between Sycorax and Caliban. They even put in quantum randomizers — that was Regulo’s idea — as part of Sycorax’s circuits, to add a heuristic element to some of the optimization algorithms. One of the other circuits reads in radio noise from the stellar background and makes it available as a computer input. According to Regulo, every now and again Sycorax will have the equivalent of a `wild thought.’ I’m giving you a long answer, but it’s another way of saying that your guess is as good as mine or anyone else’s. Nobody except Sycorax could ever tell you just where and how those stability calculations are done in the system — and Sycorax doesn’t care to tell.”
They were flying in closer to the Spiders. Rob felt no real need to check their operations, but he was always happy just to watch them. It was his first real invention, and the one that most pleased him.
The two great ovoid bodies were hanging near the surface of the asteroid, about a hundred meters apart. The eight thin metallic legs were pointed downwards, balanced delicately a few centimeters clear of the surface. Between them, probing deep into the interior of the asteroid, was set the long proboscis. As Rob watched, the great, faceted eyes turned towards him. The Spiders were aware of his presence. Somewhere deep in their organic components lurked a hint of consciousness.
Corrie had been fascinated by them from the first moment she saw one. “Why eight legs?” she had asked.
Rob had shrugged. “It extrudes material like a spider. How many legs would you have given it?”
The changes to the Spiders to speed up the extrusion process had been made quickly, and had given Rob and Darius Regulo their first surprise. The material supply rate that would be needed to keep the Spiders running at full speed was more than either had expected. Conventional asteroid mining methods would fall behind their demand. The raw materials were there in abundance, silicon for the load-bearing cable, niobium and aluminum for the superconducting cables and the drive mechanisms. Getting it out fast enough was another matter.
It had been a problem, until Rob placed an urgent call to Rudy Chernick and asked if there were any way to modify a Coal Mole to work on different materials and in a vacuum environment. A lot of technical discussion, even more hard negotiation between Chernick and Regulo, and the beanstalk project had acquired another working partner. Now a whole family of modified Moles was chewing away happily in the bowels of the asteroid, gobbling up its interior and spitting millions of tons a day of raw materials out through the chutes that connected to each Spider’s waiting proboscis.
Rob had been inside the asteroid only once, when Chernick was taking in a supply of nutrients. Not even the Moles’ extraordinary metabolism could survive on what the rocky interior would provide for them. Rob had quickly become bewildered and disoriented by the honeycomb of tunnels running throughout the three-kilometer planetoid.
“How do you know where all the Moles are, and who’s mining what?” he asked Chernick, who seemed remarkably at home in the warren of connecting passages.
The other man was tall and skeletally thin, with mournful eyes and a long, drooping moustache. He sniggered happily. “I don’t have the slightest idea.” He looked at Rob slyly. “You’re the one who gave me the idea of using the happiness circuits. I bet mine are almost the same as the ones that you have in the Spiders. The Moles enjoy planning the diggings — I wouldn’t take their pleasures from them. I give them the mining specifications on quantities and rates, and leave the rest to them. Perfectly straightforward — not like those monsters you’ve got outside there.” He peered back along the tunnel at the chute leading to one Spider’s proboscis. “How many of those things do you have? They’re uncanny.”