Lani was bright-eyed, expectant. “When can we go outside? I want to grow some crops in the sun again.”
“Nearly half a year,” Virginia said seriously. She had found that people took statements more to heart if they were laced with sharper vowels and a few bass tones.
“Never mind, we’ll have plenty to do inside,” Carl said, slapping Lani on the rump affectionately.
Virginia knew exactly what he had in mind. It was implicit in his entire psychological profile, true, but her intuition told her more. Carl had bottled himself up emotionally for decades, and that had been crucial in the survival of Halley Core. Now time and circumstance had worked its curious magic and he was free. The youthful Carl could not—did not—respond to Lani’s quiet gifts. This weathered, wiser Carl could, and would, and should.
Somewhere in the compacted recesses of organic memory, a twinge of humor and irony kindled. He’s getting what he needed, even if it isn’t what he wanted. Virginia made a note to cycle Lani in for a “routine” physical within forty days.
The prickly storm swelled. Though they had survived the worst at perihelion, a residue of heat still leaked inward. Virginia sent men and women and mechs to seal tunnels which collapsed, whole zones of shafts whose walls began to sputter and evaporate.
Warmed in vacuum, ice sublimates directly into vapor without becoming liquid. As Halley’s scarred skin blew away, Virginia began her grand experiment.
Teams of hardened mechs ventured forth from the eroded shaft mouths. They dispersed slabs of amorphous silicates, grit and grime dried and filtered and compacted through the years of mining. Quickly they spread huge fields of linked, slate-black sheets oil well-chosen spots near Halley’s equator. They were too heavy for the subliming vapors below to push them away, and the mechs made doubly sure by hammering cables to anchor the slabs.
The effect came with aching slowness. Halley spun now with a day of only three hours. At a precisely calculated moment, the silicate shields blocked sunlight from the ice. Over that zone, outpouring gas ebbed. Other areas continued, and this difference in thrust, combined over the turning face of Halley, began to minutely alter its orbit. Astronomers had long noted this “rocket effect” on rotating comets that temporarily exposed fields of dust, but it had always been spontaneous and temporary. Now it was done by design.
Virginia deployed her mechs remorselessly. Some overheated and failed, others were crushed between the large sheets as they butted and swayed in the sun-driven gale of gas. At her command, they could tilt the slabs end-on, so the protected areas suddenly leaped to life, spurting amber-tinged plumes. Deftly, resolutely, she played a dynamic symphony with the furious hurricane forces that buffeted the mechs and their cargoes. For days, and then weeks, she cupped the outraged steam of Halley to new purposes. Unbalanced thrusts aligned along the comet’s orbit, a persistent hand that swept them along a new orbit.
Four months beyond perihelion, Virginia waited for the inevitable. She had deployed fresh arrays of infrared and microwave radars, concentrated along the expected cone of the sky.
The first was slow and tiny, a marvel of stealth technology. She got a glimpse of broad, transparent vanes that radiated away the sun’s heat. Only her phased-array microwave net, operating at ten gigahertz, picked up its faint shadow. She had spread the gossamer wire receivers over a volume spanning a hundred kilometers, to get high definition. If it had been faster she might not have been able to integrate the diverse signals in time. As it was, she crisped the snub-nosed thing ten kilometers away from Halley.
Behind it, a few moments later, came something large and lumbering. It used the sun for background cover, superimposing itself on a vibrant-blue solar flare that had sprouted only an hour before from a large magnetic arch.
She caught it with a laser burst, feeling a chill run through her mind. She would never have caught the slight, giveaway ripple of ultraviolet that betrayed the incoming warhead… except that she was monitoring the flare, as part of their ongoing research program. Jeffers had been right when he insisted on retaining the dedicated science diagnostics; it paid to keep learning.
The third was fast, closing at a hundred kilometers a second, still boosting with a light-ion drive. Virginia wondered why they had left the electrostatic accelerator on, since it made the projectile much more visible. She fired at it with the newly resurrected launchers, and in the two-second delay waited confidently for a kill signature.
None came. Her phased-array net told her why. The thing was maneuvering sideways, dodging the slugs of iron. Evidently it could pick up the microwave hum of the launchers and see the pellets as they came.
She immediately fired all her harnessed laser banks.
They, too, missed. By then only four seconds remained and she did not even have time to sound alarms in the tunnels of Halley.
Desperate, she drove the power level of the of the gigahertz net up a terawatt and shifted the system from RECEIVE to TRANSMIT. The array had never been used this way. For a brief instant it could have sent a hail to a civilization across the galaxy itself, if anyone along the beam happened to be looking. The spider-web dishes could probe and pinpoint. Virginia fired a pulse of electromagnetic energy at the precise dot that swam in her triangulated worldview.
They had safe-armed this warhead. As the electromagnetic tornado burst upon it, the chip-mind aboard fired the compressing explosives before they could evaporate. The equivalent of twenty megatons of blistering fusion energy flowered in the black sky above Halley, raising a flash-burn of ivory fog from the weathered ice.
Throughout the battle Virginia had alerted no one. The men and women and families went on about their lives, untroubled. Only when workers on the surface wondered about the sudden flare of brilliance did she call Carl and deliver the news that their great battle had come and gone in the time it took Carl to put down his cup of coffee.
CARL
“Any signs of others?” Carl asked tensely.
“None;” Virginia said. “I have extended my search to a light-hour all around us, and find nothing.”
Lani came coasting into Central, her face drawn and pale. “I heard your announcement, Virginia. How close did they get?”
“As the Duke of Wellington said after Waterloo…” Virginia’s voice shifted to a heavy, aristocratic British accent, “‘It was a damned near thing.’”
“And they’ll try again, if we continue on our planned trajectory;” Carl said soberly. “They won’t tolerate us using the Jupiter encounter to loop us into the inner solar system. They’ve got years to shoot at us, remember. When we come back inward, they’ll strike again. That attack may fail, too. And the next one. But eventually…”
“Those murderers! Lani cried. “We were willing to accept quarantine, but that wasn’t enough for them! Just to protect themselves from any chance of exposure to Halleyforms, they’d kill us all.”
Carl felt the inevitability of what he had to say, the end of so many hopes. “Time to face facts. We can’t come back in from the cold.”
Lani frowned. “But that means…”
“Right. We’ve got to choose a trajectory that’ll take us outward after Jupiter. It’s the only way to stay out of Earth’s reach.”
Virginia asked, “You think that will be enough to make Earth stop?”
Carl shook his head. “We’ll have to hope so. We’ll chart a course that takes us far into the outer solar system.”
Lani looked at him, biting her lip, silent.
“Somehow,” Virginia said slowly, “I don’t believe they will be content with anything less than a departure orbit.”