Moonstruck. Part 31

"Heads up."

Kyle turned toward the call and saw a can of c.o.ke lofted his way. He bobbled the catch. "Thanks, Matt.

I clearly need the caffeine."

"What'd I miss?"

"Can't be a solar problem and doesn't look like something in s.p.a.ce blocking the light." That left the

moon suddenly absorbing light it had once reflected. That left the subject matter of a third wall, whose

virtual caption read: lunar surface. The big observatories only confirmed what Kyle, with his amateur telescope, had decided minutes after the mysterious fadeout: the moon's surface, other than darkening, looked unchanged. Optical telescopes and radar pinging alike detected no change to the moon.

"Infrared." Matt whapped his forehead with the heel of his hand. "Matt, you dummy. Ellen! Do we have before-and-after IR images of the full moon?"

"I'm on it." Ellen started typing feverishly."Not dumb, Matt. Sleep-deprived, probably. Brilliant, certainly." It was almost five in the morning. Almost time for his chopper ride to Washington, to try to make sense of this for the President and an emergency cabinet meeting "If the moon is suddenly absorbing more sunlight, it'll be hotter."

"Here's before," called Ellen. "It's an archival shot from the three-meter IR telescope facility up on Mauna Kea." A new display window opened on the wall devoted to lunar-surface findings, showing a gray-scaled disc with occasional dark splotches. The gray-coded key confirmed the predominant lightly shaded areas were around 140oC. The dark patches, in the shadows, were as cold as -170 oC.

"What about a current IR view?"

"The file is downloading now. Go figure-the Internet's slow tonight." Ellen rubbed her eyes wearily.

"Got it."

Yet another window popped up on the wall, and Kyle's eyes popped open with it. The surface of the

moon was getting colder.The details were far from clear, but at that instant Kyle knew what Clean Slate had to be. It was worse than anything he had ever imagined.

CHAPTER 37.

Two years since The Big Dim, seven years after the arrival of the "Galactics," forty-some years since a boy fell in love with the s.p.a.ce program . . . no matter how Kyle viewed it, today had been a long time coming.

No one but he thought of today's launch as Phase Three of Project Swelk.He was flat on his back, strapped snugly into one of two mission-specialist seats on the Endeavor's flight deck. He wore the uncomfortable collection of clothing and gear that in NASA-speak was a "crew alt.i.tude protection system." Besides the spectacularly misnamed antigravity suit, the "system" consisted of a helmet, communications cap, pressure garment, gloves, and boots.

In the two front seats, as on the masersat recovery mission, were Windy McNeilly as pilot and Tricky

Carlisle as mission commander. Speedy Gonzalez had the mission-specialist seat beside Kyle's. The middeck compartment was empty. A crew of four was below the norm for a shuttle flight, but this was no normal flight.

"Are we boring you, Dr. Doom?"

Kyle struggled to abort a yawn. After three weather scrubs in as many days, they'd been woken abruptly last night as the weather forecast unexpectedly broke in their favor. His limited view out the forward windshields showed merely overcast, rather than the gusty rain that had kept them grounded. "Sorry,

Craig. What can I do for you?" At this stage of the mission Kyle was simply a pa.s.senger. What could he do for Carlisle?"Nothing, Doc. Ignition is not most people's preferred wake-up call.""Don't worry. I promise I won't miss a thing." He followed the last-minute checklists and the cabin/ ground-control chatter until, with a sound like the end of the world, the shuttle's main engines roared to life. Six seconds until takeoff. Then the solid rocket boosters added their thunder, and the shuttle started to rise. They began a roll, pitch, and yaw maneuver, tipping the nose for a head-down ride to orbit, in the process gaining a view through two overhead windows of the rapidly receding ground. Thrust squashed him into his seat. Amid the noise and vibration, three Gs were far harder to take than in the training centrifuge in Houston.

"Throttle-down commencing," called Windy.

Air resistance, and the attendant stresses on the shuttle, were greatest early in the launch. Throttle-down reduced those stresses until the ship reached thinner atmosphere. The shaking and din seemed to have

gone on forever, but the pilot's calm announcement meant they were only twenty-six seconds into the flight. The jarring kept intensifying, but at a lesser rate."Commencing throttle-up."Which put them at about T+60 seconds. As the shuddering reached a peak, Kyle knew how a milkshake must feel. The Earth slivers visible from his back-row seat continued to recede.

"Approaching SRB separation." McNeilly had a hand beside the backup SRB separation switch, but the computers once again performed on cue.The solid rocket boosters burnt out in two minutes. This was farther than the Atlantis got, some recess of Kyle's mind reminded him. He felt the thunk of the separation. The noise began to abate, both because

the SRBs were gone and from the thinning of the atmosphere. From nowhere came a maddening itch on the tip of his nose. Ignoring the tickle seemed more sensible than lifting an unnaturally heavy arm.

"Negative return," radioed ground control.

More progress. They were far enough into the launch that an abort back to the Cape was no longer possible. Milestones continued pa.s.sing normally as the ship climbed and the sky turned black and starry.

"Coming up on MECO," warned Windy.

Main engine cutoff, about eight minutes into the flight. More than seventy miles up. More than

seventeen thousand miles an hour. And no separation from the external tank-two unmanned tankers awaited to top off their nearly empty ET."Three . . . two . . . one . . . MECO."Kyle's arms floated free of the armrests. His stomach lurched. His pulse raced. It was suddenly, blissfully quiet; radioed exchanges with ground control were the only sounds. As he tipped his head backward, a bony finger poked him: Speedy reaching across the gap between their seats. "Welcome to s.p.a.ce, Doc." In the front seats, Carlisle and McNeilly tended to the details of raising and circularizing their orbit. He could not tear his eyes from the panoramic view of Earth through the overhead cabin windows. He'd dreamed of this moment for forty-some years now, had an image in his mind's eye of sparkling blue and rich brown and lacy white.

The Earth stretched out below him was a cruel caricature of that expectation. Huge, angry whirlpools of cloud dominated the Atlantic. In the black ma.s.ses of cloud masking much of western Europe, lightning sparked and flashed like Thor and Zeus gone to war.

And exactly as if hostile aliens had conspired to wipe Earth clean of all life.

* * * The Big Dim was actually quite simple. The moon, like the Earth, receives solar energy at an average rate of 1345 watts per square meter. To darken the moon, convert incoming sunlight to electricity. To cool the moon, use that electricity to broadcast an electromagnetic signal . . . energy is removed instead of absorbed. Emit half of the incident energy that way, and-the moon being far smaller than the Earth-the transmitted energy is about 3% of the solar energy Earth receives. By way of comparison, the annual change in sunlight that causes Earth's seasons is only plus-or-minus 3.4%.

And if the goal is at the same time to sterilize the Earth? Merely broadcast in a suitable microwave frequency. Pick a frequency to which the Earth's atmosphere is transparent, a frequency strongly absorbed by liquid water-then focus all of that energy on the Earth. A frequency of 2.45 GHz works well . . . the frequency used inside every microwave oven.

Solar energy to electricity? That's easy: solar cells. Electricity to microwave beams? That's also straightforward: masers. Solar cells and masers are readily fabricated from semiconductors, with well understood human technology. The most common semiconductor is silicon. By weight, a fifth of the lunar surface is silicon.

But what could cover the whole surface of the moon with solar cells and masers?

Krulchukor laser cannons had already been grown on the moon, enclaves of solar cells and semiconductor lasers reprogrammed to project the mirage of the mother ship. That which has been reprogrammed can be reprogrammed again.

What humans call light and microwaves are only different regions in the electromagnetic spectrum, so resize and recalibrate new semiconductor structures to emit microwaves. Move the aiming point from a tiny, fast-moving radar buoy to the impossible-to-miss globe of Earth. Delete the code that limited the growth to small regions. Wait until the nanotech-produced texture-no dimension of its surface manifestation larger than inches, impossibly small to see from Earth-infests the entire lunar surface. Then turn out the lights and crank up the heat.

* * * "Like a freaking ballet outside, only interesting." Speedy was admiring an ET/unmanned-tanker rendezvous through a flight-deck window. "Doc. You gotta see this." Kyle was out of her sight, on the middeck. "I caught the first act." The ET had already drained one remote-controlled tanker. The load from the second tanker would bring the ET to about half filled. That would more than get Endeavor where it needed to go. The hard part of s.p.a.ce travel was reaching low Earth orbit.

"You staring dirtside again, Doc?" she persisted.

"Uh-huh." Doctor Doom was too many syllables for regular use. He'd lucked out-Doom would have gotten old. "It keeps me focused on why we're up here."

They were over the eastern Pacific, approaching the Panamanian coast. Two enormous tropical

depressions were converging on the area. By historical standards, it was early in hurricane season, but the National Hurricane Center was already up to Norman on this year's second pa.s.s through the alphabet. Central America was going to get clobbered again. He couldn't help but remember that kid who washed out to sea. It had been one death among thousands in a single storm, and there had been hundreds of hurricanes, typhoons, and cyclones since-and it was the tragedy that still gave Darlene nightmares.

His eyes were glued to the ten-inch window in the side hatch. Logically, the view was no different than what he'd seen often in satellite imagery. Maybe so, but it was more real with only a pane of gla.s.s and vacuum between him and the unfolding catastrophe. As he watched, lightning erupted like popcorn over the cloud-cloaked mountainous spine of the isthmus. More mudslides in the making? d.a.m.n Grelben.

"Doc. Since you're downstairs, check on the MDS, w.i.l.l.ya?""Sure, Craig." The microwave dump system was one of the postapocalypse retrofits to the orbiter. Endeavor had launched during a waning crescent moon; there was comparatively little Earth-bound microwave energy. Even if the moon had been full, its microwaves were a different sort of hazard than the defeated masersats. Those had focused weapons-grade bursts on small targets. The endless lunar emissions blanketed all of Earth facing the moon. The MDS reradiated the incoming, comparatively diffuse microwaves. "The panel shows all green."

"Thanks, Doc."

"Coming through." Speedy dove through an interdeck opening, with a grace in micro-G he could only

envy. She retrieved a camera from her locker on the middeck. The storm caught her attention on her return soar. With a tuck, roll, and light kick off a bulkhead, she stopped gracefully in midair. "Je-sus!"

"I wouldn't want to be wherever that monster comes ash.o.r.e."

Another well-placed kick propelled her closer. She stared out the hatch's inset window. "You understand this stuff? Really?"

The implicit admission surprised him, since there was so much he had yet to learn. Maybe he'd feel more at home when the puking stopped. That half of astronauts had a few days of s.p.a.ce adaptation sickness was little comfort. The old hands recommended keeping busy. " 'This stuff'? You mean how The Big Dim hoses the climate?"

"Right, Doc." She took a snack bar from a jumpsuit pocket. "You want half?"His stomach gurgled. "No thanks. All right, the weather. The moon used to reflect about ten percent of sunlight hitting it, and that was scattered. Now, about half the incident light is reemitted, and it all comes Earth's way. As microwaves. If the microwaves. .h.i.t water-and Earth's surface is seventy-percent water-they increase evaporation. Vast regions of moist, warm air rise, spun up by Coriolis forces." He pointed at the huge storms forming below. "Okay?"

"So far, so good."

"But more energy and more storms are just the start. Greenhouse effect is the kicker."

She nabbed a crumb that had floated off. "I don't get it."

Not her field, not her fault. "During the day, solar energy soaks into the ground. The heat reradiates to

s.p.a.ce at night, as infrared. But some gases block IR, trapping heat in the atmosphere. The effect is like gla.s.s in a greenhouse."

"Like carbon dioxide."At five miles per second, crossing Central America didn't take long; the Endeavor made the traverse while Kyle was in what Dar called pedantic mode. A hurricane was brewing in the Caribbean. "Right. But not only carbon dioxide. Water vapor is another greenhouse gas."

"Aha. The microwaves increase evaporation, producing water vapor, which traps heat, which further increases evaporation. A vicious cycle." She finished the snack bar and carefully zipped the wrapper into a pocket. "The evaporation leads to more clouds, and so to more rain."

"Yes, but not indefinitely. Hot air rises. The water vapor-laden air rises. Rain, of course, begins as airborne droplets forming in the cool upper atmosphere, condensing around airborne dust. Condense enough water, and the drop gets heavy and falls. But these microwaves evaporate water from would-be raindrops. So the new vapor rises still higher, into colder and colder parts of the atmosphere. Drive the vapor high enough, and you get permanent upper-atmospheric ice crystals instead of rain."