The Duke Of Uranium (19 page)
A loop is a closed ribbon of superstrong superconductor, moving at very high speeds, yanked through a superconducting magnetic coil like a plunger through a solenoid and kept open by its own centrifugal force, so that it forms a giant circle. When fully deployed it is tens or hundreds of kilometers across and moves at several kilometers per second; any craft with a variable magnetic drag linducer can be accelerated up to the speed of the loop, and if it has the power reserves to run the linducer for forward propulsion it can even accelerate beyond loop speed, so that the amount of fuel a shuttle or package must carry is drastically reduced.
Outgoing cargo carries a small fraction of the loop’s energy away with it; incoming cargo adds energy to the loop. When the loop is braked and coiled for storage, almost all of the energy is recovered into the brakes, so very little energy is wasted, and in fact if a ship or station happens to be receiving more than it is sending, very often it ends up with a net energy gain (for which, of course, it is expected to pay).
Phrysaba had explained that to Jak; since they were dropping off an unusually large and heavy lot of cargo at Mercury, they would be deliberately coming in on a trajectory that would require the highest delta-v permissible, to produce an exaggerated net energy difference and thus slightly increase profits.
This meant having the biggest possible loop at the highest possible velocity; it made the Spirit of Singing Port harder to handle, but they had done this many times before, and it had always worked out.
On an immense station like the Hive, almost as big as Earth’s moon, where spaceships of all kinds come and go constantly, a loop is simply left up and running, but because of its enormous angular momentum, a loop is also a very effective gyroscope, and on a sunclipper, which must move and maneuver, having a loop running for more than two or three days is a major nuisance. Thus when approaching a big station, an asteroid, or an airless world that has a loop up and running, a sunclipper deploys its loop as late as possible before closest approach, aiming to have loop speeds and directions at the outer edges match as nearly as possible during a critical period of no more than about five hours, and then furls its loop as soon as possible after cargo and passengers are transferred. While the loop is deployed, the ship is almost unmaneuverable, locked into its course until it can recover the energy from the loop.
Deploying a loop is like spinning up a lariat big enough to lasso New Jersey, fast enough to orbit the Earth, while running it through a croquet wicket. Many thousands of parallel processors run faster-thanrealtime simulations to decide when to attach another piece and when to cut it open to expand the loop.
But although machines have superb reflexes, they are not noted for their perception. Machines can calculate what is about to happen, and calculate what will happen if you change something, and they can draw it on the screen, but they cannot tell a harmless wobble from a disastrous snarl nearly as well as a human being.
So the job Jak and his many co-workers were doing was to supply judgment for the massively parallel processor system that ran the loop. He had a scale from red to green, with yellow between, and a movable pointer, on his screen; the machine showed him possibilities a few seconds into the future, and he marked them as anything from harmless to disastrous on that scale. Each evaluator saw a dozen possibilities per minute or so; every possibility was evaluated by three different evaluators, and only those which received three full greens were considered for actual implementation. The result was that with 250 evaluators working, the system could consider about a thousand possibilities per minute, which gave it an effective accurate reaction time many times that of a human being, and yet with an almost human level of judgment.
The most dangerous period was the middle period of the spin-up. When the loop was still small, just a kilometer or two across, it had relatively little momentum and any accidental waves or wobbles could be fixed by drawing energy back; when it was all the way out to sixty kilometers across, it had so much momentum that the last increments of loop material and kinetic energy could make relatively little difference. But between about five kilometers’ diameter and about thirty, it was still possible to jolt the loop enough to make it misbehave from mere normal increments of energy and material, and it was no longer possible to trust that the available forces would suffice to keep it controlled and out of various forms of dangerous behaviorsinusoidal waves that could cause it to brush the coil with explosively disastrous results, twists that could make it begin to fold in with equally catastrophic potential, and so forth. Thus, where a small number of technicians sufficed at the start and the finish, the middle required everyone who could be taught to recognize the basic pattern of trouble and move the slider quickly enough.
Outside the loop whirled at about five kilometers per second; at the end of the coil, new pieces were fed on, each ten meters or so long, folded so that both ends were attached to a welding clip. The clip grabbed the loop and welded both ends of the new piece to it, just a half centimeter apart, then snipped the loop between the two new attachment points, fast enough for the new, welded-in length to clear the entrance to the coil about a second later, as the loop came back around. Second by second, dekameter by dekameter, the loop grew and circularized into space on the sunside of the sunclipper, a mere kilometer from the thousands of monosil lines that could cut it instantly. Making the whole job harder, the angular momentum of the loop locked and held the ship in a single orientation that constantly threatened to collapse the sails, so that the sailing crew was triple its usual number and working like mad; fusions were constant, and riggers were out cutting and splicing all the time, as well. The whole process, from the three mainsails each twice the size of Africa to the city-sized habitat to the immense racing loop behind it, stretched across six thousand kilometers of a sky, a barely controlled disaster that was always less than a
second from going out of control.
A distant corner of Jak’s mind was grateful to be as busy as he was with the screens and images; if he had thought about what was happening, he might have frozen in sheer terror.
When Jak’s relief tagged him and sent him to the foot of the relief line, the process of swimming out of his chair disoriented Jak.
He gratefully gulped the icewater and more coffee that the kids serving the line brought to him, swallowed the nutrition supplement they handed him, and washed it down with yet one more round of coffee and icewater. He breathed, stretched, and focused as the line of other workers taking a break moved ahead of him. Everyone around him was also stretching, yawning, trying to work out the kinks.
The line snaked into a rest room and Jak got a welcome moment’s relief.
Less than twenty minutes after being relieved, Jak was at the head of the line. A light pinged on over the terminal operated by a woman of about forty; Jak swam over and relieved her, and within moments he was back into his screen, in that curious state of focused meditation, deciding between harmlessness and disaster. It was the tenth hour of the approach; they were far less than halfway through the process.
On the Bad Side of Entropy
The hours went by in a blur; watching the screens was like sparring, dancing, or playing some of the more intense viv gamesyou couldn’t afford an instant to speck about what you had just done or what might be coming next, all of your concentration had to be on doing the right thing in the present. Jak kept his focus, aiming for that singingon state familiar from the Disciplines, and kept working. When he had his next relief, the loop had grown from about ten kilometers’ diameter to almost thirty, and was becoming steadily better behaved.
The line of people taking relief breaks was longer now, as more people had been brought up from cargo packing, which was mostly complete. That meant everyone got a perhaps-five-minutes-longer break. The hold was now jammed to all surfaces with packed containers, and the outside of the ship was beginning to bristle with containers tied to longshore capsules, waiting to slide up the tracks onto the loop when the time came. Probably a third of the ship’s crew was working outside at the mo-ment, lining up the containers for loop launch and keeping the rigging from fouling.
People taking a break could look directly out through a big viewport at the planet Mercury itself. They were overtaking Mercury in its orbit, moving six km per second faster than the planet itself, only about 25,000 kilometers now from their closest approach, so Mercury loomed into the space beside the outer sail, fifteen times as big as the moon from the Earth and far brighter. The straight lines of the great ore
roads were visible on the daylight side; on the night side they continued as strings of lights cutting across a curve blacker than the illuminated dust around it, like a photograph cut and pasted to its own negative.
The immense Caloris Basin, one of the larger impact craters in the solar system, was about two-thirds in daylight; the third that was in dark was widely scattered with bright lights, for the processes that had shaped Caloris had provided vast, rich deposits of many kinds of ores close to the surface, and there were mines everywhere. Within the dark part of the Caloris Basin, a little sprawl of bright dots, looking as if some giant had glued the Pleiades down on the face of the planet, marked Chaudville, and north and to its left Bigpile was a cross-shaped patch of bright lights; those and the roads were the only man-made features that Jak could definitely identify.
A soft, melodic ringing from the public address system announced that it was important to listen to the next message. Everyone in line, and at every station, was silent at once. “Mercury ground control indicates that we have a substorm in our path,” the voice of the captain said. “No possibility of a course correction unless we abort. Storm is rated as slight-to-moderate in risk. I’m going to ask all personnel to come inside within ten”
A strange, undeniable sensation grabbed Jak’s attention; he realized later that it was the subtle shift in direction of acceleration, felt inside as if the gravity had shifted. At the instant he felt it, he knew only that it was something he didn’t want to feel, something wrong.
Through the viewport, he saw an odd, folded curve that had not been there a moment ago.
One mainsail had collapsed, and was fouling several other sails; as random fusions spread up the lines, the simple, beautiful curves of the sails were becoming a tangle like a wadded bedsheet.
The crewies spinning up the loop stayed at their posts and kept working, but even they kept stealing glimpses at the big viewport. Then, as suddenly as the shadow of a bird passing overhead, tangled sails dropped past the viewport. A terrible groan ran through the ship as the unaccustomed forces yanked at its structural members; there was a noise like a great explosion, and then nothing but the usual background noise of the life-support systems. At all the terminals, the loop workers sat back, as if stunned by a rock that had flown out of the screen at them.
“This is the captain. People, we’re on the bad side of entropy. The boom you heard was the jettison of the loop coil, taking the loop with italong with about a quarter of our total sail area. Preliminary radar result shows that we will at least not have to pay damages for collisions or unauthorized landings; it will probably go into a salvageable solar orbit. Cargo switched is scrubbed, repeat, scrubbed. Financial consequences will be assessed as soon as possible for crew debate and vote. Astrogation assures me that we have enough of a gravity assist so that with remaining sail we can reach Earth in about thirty-six days, just eight days behind schedule, and once there we will be docking wherever the insurers tell us to, for an overhaul and a decision. I’m terribly sorry to say, however, that at the moment we have a complete failure to function as an effective business.” There was a long pause. “I now ask that all personnel, including
those inside, run a pizo check. We are receiving no transponder signals from the debris, so there is no one alive trapped in it; we need to know if everyone is still here. Please remain quiet and orderly until pizo check is completed. If you don’t have a pizo, please use your purse; call 8888 and type in 444 at the cue to let us know that you are all right. Cue in five, four, three, two, one.”
At the bell tone, Jak logged in. He didn’t have a pizo because he was not yet officially a member of the ship’s company.
One of the many ways in which this had happened at the worst possible time was that your pizo was normally a co-worker with whom you shared shifts, and ideally interests as well, so that you were in a good position to check on them at once. During cargo switch, though, everyone worked everywhere, as needed, and often one pizo had been working outside on sails while another was inside on container loading. Mostly, they found each other through their purses immediately, but the few remaining cases were an anxious matter.
After about a half hour, the tall girl behind Jak in line said, This is bad. If everything was fine, it would have finished by now.” She wiped her eyes. “I’m just glad that Krea was on my purse two seconds after the captain announced pizo check.”
Jak had been about to say he hoped that it would be someone that neither he nor she knew, but luckily before he spoke he realized how stupid that was. In the little world of the ship, there was no such thing as a person you didn’t know.
“So, since I’m new, do you mind telling me what’s going on? What are they doing right now?”
“Following up on pizo check, rechecking all their missing ones, just to make sure it’s not the one in a million chance of a purse being damaged and the owner being okay, or some gweetz who took off his purse while working, or anything like that. Or it could be that they’ve got some noncalls, which always take longer to check back on. That was a big scary accident. There could be more than one person
