Delmor Caton, Surface Operations shift supervisor at the industrial constructions in progress or at Omsk, felt an empty feeling taking hold deep in his stomach. His throat tightened in an effort to coax up moisture against the sudden dryness.
It was fear.
He had thought he would grow immune to it after the things he had seen and lived through in the course of the last three years. But it was never long before something else happened to remind all of them that there would probably never be any escape from the danger for the rest of their lifetimes. Earth had been devastated before, and mankind had lived in terror for centuries afterward. . . .
Alarm signals whoop-whooped through the domes and tented excavation sites gouged into the ice on Saturn's sixth major moon, Rhea. Simultaneously, alerts were flashed on the emergency bands to mobile units scattered across the surface and to the commander of the military-style training base that the Security Arm operated two hundred miles away. The drills had become second nature. Surface access locks and bulkhead doors throughout the site were closed; all occupants in the first ten levels down from the surface who were not already kitted up began putting on suits; vehicles caught outside sealed hatches and raced for whatever cover they could get to. Caton glanced at the others in the upper control room overlooking the workings around the main shaft, clearing desks and consoles, shutting down systems, and helping each other secure helmets before evacuating to the communications center below. He snapped a switch to kill the sirens and leaned forward in his seat toward the console microphone.
"Alert is confirmed. Multiple impact hazard zeroed on this area in fifteen minutes, twenty seconds if not neutralized. We're getting everybody underground. Regular drill, Code Orange. Surface operations are closing down. Out."
One of the wall screens showed a view of Athena, currently between the orbits of Jupiter and the Asteroid Belt on the far side of the Solar System—an almost-Earth-size ball of white-hot vapors and magma with plasma tails millions of miles long braided into fantastic forms by electrical forces, giving it the appearance of an animal head glowering between fiery horns. Thousands of years before, when proto-Venus was a similar rogue incarnation recently born of Jupiter, the mythologies of cultures worldwide had depicted it as fiery cow, bull, or wolf deity returning periodically to loom terrifyingly in the skies and wreak destruction across the Earth. Although Athena itself was at present far away, its rampage through the Solar System had effects that could strike anywhere.
Caton rose and turned to find Tanya, one of the operators, stopped halfway to the door, still clutching her helmet and staring back at the image. She was one of the few survivors to have made it to Saturn three years previously, rescued by the Kronians from one of the pilot Terran scientific bases left stranded on Mars. Tears of rage and frustration glistened on her face. Not Kronian-born or raised here from childhood as an immigrant, she was still struggling to adapt to the new ways of living, knowing that everything that had been familiar was gone permanently, and nothing resembling the world she had known as home could exist again until long after her lifetime. "Why? . . . Why won't it leave us alone?" she whispered.
Caton handed her the helmet, ushering her toward the door. "Because that's the way it is. Come on, we need to go." His tone was gruff but not without sympathy. He hoped that the people up on the LORIN stations were on form today. Everything depended on them now.
A million miles above Saturn, Landen Keene sat tensely in a seat to one side of the Fire Controller's console in the command room of LOng Range INtercept Station 5, between the orbits of the second and third outer moons, Iapetus and Hyperion, and 30 degrees north of the plane of the ring system. A large screen to one side showed a view of Saturn's banded globe seemingly floating in a shining elliptical ocean formed by the rings seen obliquely. In normal circumstances the sight would have been stunning. Right now, however, all attention was focused on the image hanging above the holo-table in the center of the floor. It showed a sector of the moon system plane outside the rings on the near side of Saturn. Rhea was close to the center, looking like a mottled gray marble. Titan, farther out and three times its size, sat just inside the image volume as a smoky brown ping-pong ball. And coming in from the side on a slanting trajectory, a pattern of red points, moving perceptibly, denoted the swarm of dark objects that had appeared suddenly from the outer Solar System, hurtling inward into Saturn's gravity well.
The encounter with Athena had deflected Earth into a more eccentric orbit and perturbed the motions of all the inner planets with consequences that were not yet clear. In addition, the attendant debris pulled out of Jupiter at the time of Athena's birth, and the bodies sent off in wild directions by Athena's several interactions with the Asteroid Belt since, had created a multiplicity of rogue objects, some of which traversed paths reaching out almost to the orbit of Uranus. The incandescent ones, such as the several score of new comets torn from Jupiter, and hot material ejected from Athena itself, were fairly easy to track—although prediction of future motions was complicated by electrical disturbances that made the old laws of celestial dynamics unreliable, at least for some time to come. But dark, colder objects could appear unexpectedly anywhere, at any time.
All prospects of support or supply from Earth had gone. The environment on and around Earth had remained too hostile to contemplate reestablishing a human presence there in the time since the Athena catastrophe occurred. Hence, the survival of the Kronian colony depended crucially on technology in all its forms and the rapid development of more advanced ones. People from Keene's kind of background were invaluable. He was on LORIN 5 to learn more about Kronian operations involving nuclear technology—specifically, in this instance, the system of orbiting defense stations that had been put up around Saturn's moon system for protection in these violent and perilous times.
Jebsen, the Fire Controller, Kronian-born and characteristically tall, with fleshy, swarthy features, moved his head above the neck ring of his pressure suit to scan the updates from the long-baseline search radars and targeting computers. The inside of a LORIN station was cramped and cluttered. The need had been to get them up fast, when the first effects of Athena's raging began manifesting themselves.
An operator called from a position to the right of Keene and above, between a bulkhead support and bank of cable boxes. "Fifty-three objects registering Class C and up. Eleven major Titan hazards, aimed and locked. Eight on miss trajectories. Remainder of scatter pattern implicates Titan immediate sector, nineteen at forty-two percent mean, Rhea fifteen at sixty-eight."
"Pods within range and able to bear total twenty-three rods," another voice reported. Jebsen took in the confirmation from the displays. Not good.
The LORIN stations were adaptations of a space weapons system devised as a precaution years ago, when political tension between Kronia and Earth had raised the possibility of armed conflict—which, as things turned out, hadn't materialized. They carried a complement of ejectable pods that powered themselves to a safe distance of anywhere from fifty to several hundred miles before deploying a cluster of heavy-metal lasing rods that could be independently aimed at multiple targets. The device was pumped by the energy from a fission bomb explosion, focused in the nanoseconds before the rods vaporized into concentrated X-ray laser beams capable of destroying a spacecraft from ten thousand miles.
The problem, however, was that despite the effort that had gone into expanding Kronia's manufacturing capability, supplies hadn't been able to keep up with usage over the past several months. More targets were materializing than there were rods available to shoot them with. Complicating matters further, bodies of solid rock could absorb more energy than hollow structures, which often made it prudent to target two or more rods on something that presented a particulary dangerous threat. In the present situation, the computed probability of impacts on the surface of Rhea was greater, while the consequences of letting anything through to Titan, where more Kronian facilities and settlements were concentrated, would be worse. But Titan had a dense atmosphere, while Rhea was unprotected.
These were the factors that Jebsen had to balance. To risk fewer lives with higher probability, or more lives at a lower probability? Which people were the more expendable? The longer he took, the more the odds would tilt. Keene licked his lips, thankful that it wasn't his responsibility.
Jebsen recited a series of identifications and coordinates in the abbreviated language used for voice input, selecting what he judged to be a compromise of the most menacing situations from both groups. The computers assigned targets and presented a revised fire plan.
"Thirteen minutes to first impact on Rhea," an operator called.
"Go with it," Jebsen instructed.
"Designator acknowledges and confirms."
"Lock-on complete."
Jebsen nodded. "Auto fire."
Twenty-three beams of radiation concentrated a trillion times denser than that from a hydrogen bomb lanced across space, each causing a miniature sun to flare briefly in the remote regions of Saturn's outer moons. Of the incoming objects that remained, two reached Titan to break up in its atmosphere, one of the fragments demolishing a surface dome with twenty-two occupants. On Rhea, the industrial excavation and construction sites suffered relatively minor damage with no casualties this time. However, the military training facility two hundred miles away was devastated under a cluster of impacts. Forty-six individuals were unaccounted for afterward; but the actual death toll probably wouldn't be known for days, if not weeks.
A supply ship delivered more pods to LORIN 5. Jebsen was back on duty eight hours later.