T-3/E49851 had been built three days ago, its shell cut and curved and welded by the CAM machines in the fabrication center. It had been delivered to the cargo assembly center twelve hours ago, filled, sealed, and cycled into the launch queue six hours later, mated with its thrust disk of reinforced ice barely twenty minutes ago.
At five minutes after two, E49851 started its dizzying trip up out of the catacombs, bursting into the sunlight at the foot of the tower at a brisk fifty kilometers per hour. Even at that clip, the ride up the side of the tower took longer than the ride to space which was to follow.
At the top, a handler crane grabbed the spacecraft and lowered it gently into the catapult. In the launch operations center, a dozen stations ran a checklist of a hundred queries. The first clearance was from Laser Control, the last from Security; when it came through, the computers took over.
In a sudden convulsive moment, the T-ship was in motion, dragged upward by the accelerator ring, boosted from beneath by a giant’s breath. At the mouth of the tube, the accelerator ring split and fell away, and the capsule shot skyward, flying free.
The instant it cleared the launch tube, the T-ship began to slow, fighting drag and gravity, trading speed for altitude, tracing a trajectory familiar to every child who had ever hurled a stone at the sun.
Half a kilometer away, the HEL bank, twenty parallel half-gigawatt free-electron lasers under one sprawling roof, waited the call. When E49851 was five hundred meters above the castle, Unit 9 jumped to life, sending a five-hundred-watt pilot beam out through the bank lenses, along the nitrogen-filled beam tunnel, and up through the center of the castle to the mirrors. Guided by the tracking system, a single mirror directed the pilot beam against the broad base of the capsule.
Still the capsule climbed, still the capsule slowed. Two kilometers, three, three and a half. Any moment, it seemed, it would begin to fall back. And then the great bank of lasers came to life as one. The ten-gigawatt beam filled the full diameter of the beam tube, caught all twenty mirrors, and leaped across the sky to the broad base of the freighter.
The first pulse vaporized an almost invisibly thin layer from the ice disk, forming a vaporous sheet of pure, clear, superheated steam. A second pulse, a microsecond later and a hundred times stronger, shattered the molecules of water vapor into an atomic cloud of raw hydrogen, oxygen, and electrons, a plasma hotter than any chemical rocket flame, hotter even than the surface of the Sun. The plasma expanded savagely outward, kicking the spacecraft upward, as though it were the piston in a bizarre engine.
A thousand times a second, the lasers cycled through their double pulse. The awesome seamless roar of the closely spaced explosions was moderated only by distance, the pitch changing as the capsule accelerated, Doppler-shifting into the familiar falling, fading scream of a T-ship.
In the launch operations center, what little tension there could be in a routine repeated more than sixty times a day had evaporated when the thrust beam picked up the T-ship. The T-3 was riding the beam now, accelerating toward orbit, safely out of reach. Even the launch security officer, the man in the loop on Kasigau’s air defenses, sat back in his chair and reached for his drink.
The failure of the AI protocols in the Houston incident had led to the LSO being given unprecedented responsibility. Now, the AIPs could kill. The LSO had gone from being the only station that could call down the fire from the mountain to the only one that could stop it. Which meant that the LSO’s errors now would be errors of commission, not omission.
Yusuf Alli had not welcomed his newly elevated status. Kasigau was ringed by airports—the big one at Mombasa, the fields at Voi and Malindi, and fifteen rural airstrips within the primary air control area. The air traffic swarmed like bees around a hive. But every time a red light came up on the board, Alli had thirty seconds to call for a hold, and then one minute to make his decision. If he made a mistake, people would die.
Through the first three weeks under the revised protocol, Alli had dealt with his anxiety in a straightforward way. He always called for a hold, and then always gave the target a green. He had yet to be wrong. He knew there was some risk, but if any air traffic managed to reach the threat envelope of a T-ship on the climb, the defense system would bring it down without getting a second opinion. It was, he thought, foolproof.
Then the contact alarm sounded, and Alli jerked forward in his chair, choking on his tea.
“Hold,” he sputtered. “Hold!”
“Tracking missile,” said the board. “Threat category three. Risk category: moderate. Time to intercept: twenty-one seconds.”
Alli wasted three seconds staring at the track of the streaking missile. “It’s a clean miss,” he protested. “It won’t get within fifty klicks of the can.”
“Risk category: high. Time to intercept: eleven seconds.”
Alli’s eyes danced frantically over the displays. “What’s the danger? What can they hit?”
“Possible beam occlusion. Time to intercept: five seconds.”
At the same time, someone was screaming at him, “Burn it! Burn it! They’re going for the beam!”
Ashen-faced, Alli brought his palm down on the fire mushroom. One of the twenty lasers abandoned the synchrony of the launch rhythm, as atop the castle an auxiliary mirror rotated a few degrees. A defensive beam locked on the hurtling missile, and an instant later the missile exploded.
“Got it!” exulted Alli.
But the alarm kept sounding, and the displays continued to track something—now a cloud of a hundred smaller objects, still climbing as they fanned out. Then each of the smaller objects seemed to explode, and the missile was now a scatter of marble-sized projectiles. Moving nearly as fast as the missile itself had been, the chemical buckshot intersected the beam.
The first pulse heated the binder holding the projectiles together, and they blossomed into a dense cloud of aluminum dust. The next pulse, striking the fine particles, lit a myriad of tiny plasmas that quickly merged into a huge, sun-hot flare, dissipating the beam’s energy as light and heat. Only a tiny fraction of that pulse got through to the T-ship. The echo, used for tracking and guidance, was smothered completely. The next cycle was completely choked off.
At full power, the launch cannon could have burned through the cloud in a matter of seconds. But with no positive track on the target, no reflection back from the T-3, the laser controller declared a scrub and shut the HEL array down.
Three hundred kilometers away, the freighter began to fall, as though the string holding it aloft had been cut. Before long, it reappeared on the radar displays, no longer eclipsed by the dissipating cloud.
“Can we get it back?” the launch boss asked, little hope in his voice.
“She’s tumbling from the drag,” reported one station. “There’s no target.”
“Can we burn it?”
“No. Too much atmospheric absorption, and we’re losing the angle.”
“Jesus Christ,” the launch boss said. “Where’s it coming down? Indian Ocean? God, just drop it in the ocean—”
The answer was slow in coming. “South China Sea.”
Relieved expressions blossomed throughout the room.
Then the tracking officer added, “Maybe landfall in Malaysia. Singapore. I can’t be sure.”
“Damn,” breathed the launch boss.
“Can’t we warn them?” a sweaty and pale Yusuf Alli burst out.
Silently, his mouth tight with anger, the launch boss shook his head. “And tell them what?” he asked. “To put up their umbrellas? It’s coming down hard. There’s no place to hide.”