Van Kessel broke in. He liked to talk better than he liked to listen. “Basically we’re dealing with laser beams and active track elements–those pistons, you can see them on the supports, that continually push the track this way and that if the beam starts to wander off target. Acceleration is actively controlled by the capsule itself, broadcasting accelerometer readings to the power-control units on the upcoming section of track.”
“Right,” Van Kessel shouted. “If a load leaves the launcher a centimeter to one side of its true path, or a centimeter per second too fast, it’s going to be hundreds of meters wide by the time it reaches apogee. It could miss the spider web at L-1 altogether. We’re talking dead loads, of course. The capsules can adjust their flight path after they leave the launcher.”
“Drift track,” said Penney. “The load is already at escape velocity–that is, it’s supposed to be–and it just glides along without friction while we make final adjustments in aim. At the end the track curves gently away beneath, following the curve of the moon, and the load keeps going straight over the mountains into space, neat as you please.”
Sparta stood on the track with the two men. It was lunar morning, and the gleaming, uneroded, unoxidized metal of the quiescent launcher pointed directly at the sun. The loops of the guide magnets circled the three of them. The gleaming loops receded on both sides, seemingly to infinity, constricting until they seemed to become a solid bright tube of metal, finally vanishing in a bright point. It was like looking through a newly cleaned rifle barrel. When she turned and looked in the opposite direction, the sensation was the same.
The launcher was a linear induction accelerator–in effect an electric motor unrolled lengthwise. The moving capsule played the role of rotor, while the track played the role of stator. As the capsule, levitated on strong fields generated by its own superconducting magnets, passed from one section of track to the next, the track’s electric fields switched phase behind it and in front of it, pulling it forward ever faster, just as in an electric motor the rotor spins faster as current to the stator is alternated faster.
But if the alternation reverses phase, the rotor can be dragged to a violent halt. Before Sparta visited the control room she examined recordings of the near-fatal launch sequence; they confirmed Van Kessel’s report that the phase had been reversed in these several sections of track during Cliff Leyland’s launch, slowing his capsule so that it failed to achieve escape velocity.
It had taken the trackside monitors a split second to note the failure and switch the track off altogether, preserving the capsule’s momentum. Another fraction of a second passed, and the fields came back on, restoring acceleration to the capsule–but it was too little and too late to boost the capsule to escape velocity.
As Sparta walked the track, inspecting it with senses that would have astonished the two engineers, Sparta could see no sign of damage or tampering. She paused at the accident site and stood quietly a minute. She was about to turn back when suddenly she felt a queer sensation, a kind of queasiness accompanied by an inaudible chittering in her head. She looked around but could see nothing unusual. The sensation passed as quickly as it had come.
“Bear with me while I make sure I’ve got this straight: as it accelerates, the capsule–or the bucket, for dead loads–transmits coded information about its exact position and rate of acceleration to these power-control stations, telling them what phase and field strength and when to turn the track sections on?”
“Strange, wasn’t it?” Van Kessel said, nodding again. “An adjustment in launch velocity so precise that Leyland’s orbit would bring him right back down where he started. The odds against it are almost impossibly large.”
“Yes, and it’s sound statistical thinking. It’s why I wanted to see the hardware for myself.” Sparta was silent a moment, staring in the direction of what everyone was already calling Crater Leyland, far away on the slopes of Mount Tereshkova. She turned. “Can we have a look at the loading shed?”
A few minutes later Sparta and Van Kessel were peering through a thick glass window at the interior of the loading shed. The graceless steel barn, lit by rows of bare blue light tubes, stretched for almost half a kilometer beside the launcher track at ground level; a forest of steel posts supported its flat roof.
Penney had gone on to the control room, but the loquacious Van Kessel was delighted to continue squiring Sparta around. “You should see the place when it’s working,” he said. “All those tracks are full of capsules shunting along like cars on a carnival ride.”
The floor of the huge shed was a switching yard, a spaghetti platter of magnetic tracks, laid out so that empty capsules and buckets for dead loads could be loaded at the far side of the shed and shunted forward gradually, one at a time, steered to their designated places in line. As the capsules approached the launcher they were grabbed by stronger fields and shoved into its breech.
Dead loads and inert freight capsules were handled by robot trucks and overhead cranes, but for human passengers and other fragile cargo a pressurized room with docking tubes was provided at one end of the shed. Sparta and Van Kessel were in it now, standing before its big window, still suited, their helmets unlatched. Waiting capsules were lined up at platform’s edge. The place had all the charm of a subway platform.
Out in the shed nothing moved accept dancing shadows cast by a lone robot’s welding torch. Sparta turned away from the window. She ducked through one of the docking tubes and squeezed through the hatch into an empty capsule.
“We like them here an hour early, but people who travel a lot can usually get themselves strapped in and do a system check pretty quickly–ten minutes or so.” Van Kessel extended his hand to help her as she climbed back out of the docking tube. “We have manned-launch attendants here to assist.”
“No, the capsule’s are designated in advance, usually the day before. We don’t like to send up any extra mass that has to come back down again, so we talk to L-1 and try to calculate the return trip fuel requirements at this end.”
She glanced at it, and in that instant committed it to memory. “As you can tell, the economy of Farside Base hangs upon your whim, Inspector,” Penney said lightly. “We’re all waiting for you to let us get back to our jobs.”
The night of his escape, Blake had spent hours haranguing the flowing waters of the Seine from the cobblestones of the Quai d’Orsay before his irresistible urge to talk finally faded into mutterings, and he was able to sink exhausted to the ground in sleep.
The coppery light of morning was reflecting from the ripples in the oily river before he thought he could trust his own mouth. At last he walked to a cafe and made an anonymous call to the police to report an “accident” in the basement of Editions Lequeu on the Rue Bonaparte.
In his present mood he would not have deeply mourned the death by chlorine gas of Lequeu and Pierre, but he knew too much about toxins and dosage to believe that the two men would suffer anything worse from the episode than lingering coughs. He had no doubt they had long since made good their escape; still, it wouldn’t hurt to let the police paw through whatever remnants of the Athanasian Society had been left behind.