The Heart of the Comet

by David Brin

  Carl shouted. “Don’t get to close!”

  Too late. Samuelson’s big industrial laser had finished off the purple stuff, all right—and then hit a vein of carbon-dioxide ice, vaporizing it instantly. A gout of steam shot out of the hole and blew Samuelson away, spinning.

  “Lani! Slap that sealant in now,” Carl sent. He released the line, letting Samuelson get clear. It was going to be messy around there in just a second.

  Lani maneuvered at the end of a tether, holding the snaking blowline in both hands. —Here goes.—

  Sticky yellow sealant spattered over the cleaned holes. Carl and Conti played fan lasers on it at the lowest setting, to flash-dry it.

  Lani worked her way around the collar of 3E, shooting thick coats of yellow over the rents. Here and there it buckled from pressure, but she quickly spewed more on to reinforce the barrier.

  —Not supposed to use it this way,—Conti sent. —Too thick. We’ll run out.—

  Samuelson returned, velcro-climbing the walls to rejoin them. —Anything thinner, she’ll crack right through.—

  —There’ll be none left.—

  “Cut the crap,” Carl said sharply. If you let a crew bitch they lost concentration and didn’t give their best to the job.

  Lani called, —I’m done.—The steam petered out.

  The sudden silence was startling. Carl cast off from the shaft wall, able to hover now that the sucking draft had stopped. There was hardly any air pressure left. “Maybe that’ll hold it.”

  Samuelson sent, —What the hell was that?—

  —Something that grows in the ice,—Conti said.

  — —Come on, in ice?—Samuelson asked sarcastically.

  —No other way possible,—Conti said flatly. —Perhaps they get through cracks? Through softer snow veins? This is not any terrestrial form!—

  —But so big,—Lani said. —What Saul found were mostly microorganisms, correct?—

  —Yeah,—Conti added. —And the green gunk and the threads, they don’t chase you around, last I heard.—

  Samuelson laughed. —These ’uns are bigger all right.—

  “And strong. It breaks through insulation,” Carl said.

  They hung in the near-vacuum, staring at one another. Samuelson kicked off the wall and gestured upward, where splashes of phosphors dotted away into a long V with perspective. —Could happen anywhere in th’ shaft.—

  Carl shook his head. “It came through close to the collar, nowhere else. What’s special about this spot?”

  Conti said, —Something about the collar, where it fits to ice?—

  “We’ll have to check every collar, every intersection.”

  Samuelson said, —Damn right. We better collect all the bits of it that got blown into this shaft, too.—

  “Good idea,” Carl sent. “Let’s get to work.”

  They spread out through the shaft and nearby tunnels. Carl snagged several drifting purple glops and stored them in a plastic carry bag. Blobs of jelly floated free or had stuck to walls. It was sticky and left a smear on whatever it touched. He kept a running commentary to Central, describing the lifeform to Malenkov. Saul Lintz came on, peppering him with questions. He had no idea how to answer. Saul demanded samples immediately.

  “We’ll all have to get decontaminated before returning to any pressurized zones, I’m sure of that,” Carl said.

  —Well, do the best you can. I’ll get some sample bottles to you.—

  “I’ll make do. Don’t let anybody into this section.”

  —You think it’s that dangerous?—

  “Damn right.”

  He broke off and kept searching. His team spread around, checking intersections for signs of buckling. Something was nagging at him but he had no time to stop and think. The purple chunks had drifted far and wide and he had only a few people to retrieve them all.

  At the tunnel leading horizontally to Central, Samuelson found a purple tip just sticking through the plastaform. He called Conti and the two of them took a sample.

  They were careless.

  When Carl got there a few minutes later, both of them were slapping patches on themselves and yelping with startled pain Through their faceplates each looked surprised, white-faced, eyes big and jerking around.

  “What happened?”

  —I snagged this piece and it got away from me,—Samuelson said. —Conti grabbed it and it… ate through his glove.—

  There was a big, awkward patch on Conti’s right hand. “I suppose you brushed the piece with your arm?” Carl asked.

  —Yeah, and the damned thing stung me.—

  Conti’s face was twisted into a self-involved grimace of agony. —Getting’ worse.—

  “Samuelson, take him. The two of you go to the emergency entrance lock. I’ll call Malenkov and let him know you’re coming.”

  —Wh…what you think it is…doing? —Conti asked.

  Eating, Carl thought, but kept it to himself. “Get to the doctors.” He gave them both a push inward. “Hurry!”

  In the next hour Malenkov sent him reports on their condition. The purple thing had eaten through fiber covering their suits, probably reacting to it as potential food. —Maybe it just likes long chain molecules,—Malenkov had suggested. Once inside, it burned the skin. Some probably had gotten into the bloodstream. Conti and Samuelson reported a spreading, dull ache. They were sedated and under observation.

  Carl warned Lani and kept searching. Nearly an hour later he suddenly had an idea.

  “Saul! Lintz! You there?”

  The cross-link clicked and hummed, and then, —Yes.—

  “This purple stuff is light, moves easy. Most of what we cut away got sucked into the holes.”

  Carl visualized the alternating layers of inert material and vacuum that made the wall insulation. Beyond the insulation was a full two centimeters of helium, intended to isolate the wall from ice. It also provided a route for boiloff to swarm upward to the surface and escape. “Where’s this shaft’s venting go?”

  —Shaft Three vac line funnels everything from sleep slot one to the surface. That’s not my department, though. You’d better ask Vidor.—

  “No, listen. We always think of boiloff escaping upward, right? But the wind we had here, it was strong.”

  —Yes. We lost a lot of air.—

  “Point is, that air gusher was big enough to blow some back inward.”

  —Maybe. It’ll leak out pretty fast, though, even… Oh, I see. You’re worried about…—

  “Right. The purple stuff. It’s been carried by the air back toward Central.”

  —There are storage vaults along there, and…—

  “Right.” Carl hesitated, then decided. “Saul! I’m overriding Malenkov during this crisis. As of now, you’re out of quarantine. Shanghai Quiverian and anybody you can find. Get down to Three J. You bio guys better think fast. I bet these things’ve got into sleep slot one.”

  SAUL

  Saul blinked wearily through a double-antihistamine haze as he finished wiping the last green traces from the edges of the filter unit. Reduced from high science to scut work, he thought grumpily. Mama took in washing to send her little boy to college—to do this?

  Of course his real “mama” had done no such thing. She had been a colonel in the Israeli army, a hero of the ’09 liberation of Baghdad, and probably would have approved of her intellectual son’s being forced to use a bucket and mop, from time to time.

  Still, the ironic fantasy amused Saul, so he nursed it. He gritted his teeth and pounded the filter back into place. Thirty years of education, and a half-billion-mile trip into space—all to be a janitor. It confirmed his long-standing belief that there was, indeed, such a thing as progress.

  At least the present crisis appeared to have taken him off the pariah list. Every hand was needed to fight the Halleyform infestations, and few begrudged him an occasional sniffle.

  Done, at last.

  Saul sealed his sponge inside the bucket and strippe
d off his gloves. He looked over the rows of coffinlike sleep slots, foggy from internal chill and condensation, each showing a dim, hibernating form within. For two days he had been down here in the chilled chamber, trying to keep the infestations out of the slots.

  Beyond the rows of sleepers, a workbench lay strewn with bits of glass and electronics torn from a half-dozen gutted instrument panels. A tall form stooped over the clutter.

  “You about finished with those lamps, Joao?” Saul called. “I promised them to Carl soon.”

  The sallow-faced Brazilian shook his head and muttered sourly, “I have only unpacked and mounted four bulbs since you last asked, Saul. Give me time!”

  Quiverian obviously did not like being dragooned into doing “Stoop labor” out here in sleep slot 1, where it was cold and dangerous. Saul had been forced to go down in person to Central and drag the man away from a long, rambling, time-lag conversation with an Earthside planetologist colleague. Until then, Joao had behaved as if the total mobilization had nothing to do with him.

  First job had been to go over every inch of the sleep-slot chamber, cataloguing infestations. Then had come long, grueling hours of scraping, wiping, disinfecting. The air-circulation inlets had fouled with the threadlike lichenoids, nearly choking off a whole row of lots. Except for one brief sleep period, the two men had been at it nonstop for almost forty hours.

  Thank a merciful heaven Virginia ’s mechs report few problems in the other two sleep slots!

  At last, when Quiverian had seemed on the verge of rebellion, Saul had put him to work assembling the hydrogen lamps, an easier job than stoop-and-swab labor.

  “If you’re in such a damn hurry,” Quiverian groused, “why don’t you wake up lazybones over there. Put him to work doing something more useful than snoring and warming the whole cave with his electric blanket!”

  Saul glanced at the recumbent form of Spacer Tech Garner, lying on the fibersheath floor in a dark corner. Garner had been on duty for four days straight. The man was just catching a few hours’ shuteye before going back out to join the battles once again. In comparison, Joao’s work here had been a holiday.

  “Leave him alone, Joao. I’ll take the first four lamps and test them. You just keep working on the others.”

  He paused, then added, “Only please, Joao, be careful, will you? Try not to break any more of those bulbs. It’s a long trek back to the supply store.”

  Quiverian shrugged. “First you say to hurry, then to be careful. Make up your mind.”

  Saul realized the man would wear him into the ground it he remained here. “Just do the best you can.” He picked up a set of the spindly beacon lamps—meant to flash navigation/location reference to astronauts working on the moon or asteroids. He had an idea they might be useful in another function, here.

  We’ll see if they’re any good against a form of life that lives in space.

  He set forth in a low glide toward the entrance to Tunnel J, an amber-colored exit from the great chamber containing sleep slot 1. Right now the place was eerie with the lights dimmed low. The vaulted recesses seemed deeper, more mysterious, like naves in an ancient tomb. Fibercloth rounded the edges, but the vast cave was still an irregular hole deep under the ice. One didn’t dwell on how many tons hung overhead, in the kilometer or more to the surface.

  At the center of the chamber floor, casting shadows in the light of a few active glow panels, the fore end of the slot tug Whipple lay at the center of five isles of casket-shaped containers—the individual resting places of more than a hundred hibernating men and women.

  If we lose this battle, will any of these people ever see light again? Will they breathe, and laugh, and love?

  Saul wondered, Does any of our desperation penetrate, and disturb their slow dreams?

  It was dark as a sepulcher in here. It was also getting damn cold.

  The lights were dimmed to save energy. The fusion pile had been damped two weeks ago, when all but fourteen humans had been cooled down, and everybody expected a long, quiet, boring watch ahead. Now there wasn’t the manpower to supervise a fully stoked reactor. Every hand was needed in the passages, in the utility corridors, or in sick bay.

  Anyway, light was one of the things that attracted the lichenoids and the purple things. That and heat, and air, and food…

  I guess it’s no accident we like the same things. The biggest difference is that the Halleyforms only experience spring briefly, every seventy-five years or so, when the heatwaves come migrating down from the sun-warmed surface. They’re built to act, and act fast, to take advantage of the sudden season.

  Saul was still mystified by the abundance of types—by the complexity of the forms that fed on the green, algaelike growths. They violated the tenets of modern biology by existing at all.

  But he was practical enough to stop muttering “Impossible!” to himself after a while. Later, he could try to discover an answer. Right now. he had to find ways to stop them.

  He was getting better at low-G maneuvering. Still, his feet got in each other’s way on alighting near the open Tunnel J hatch.

  Fortunately, there were only a few entrances to sleep slot 1. Tunnel J was the critical one. Only a few hundred yards down that way, and up one level, Carl Osborn and his tired crew were wearily scouring away the green Halleyform variants the spacers had taken to calling “gunk”… trying to rid a critical passage of the food supply grazed on by the horrible purple worms.

  So far, liberal doses of certain antiseptics and synthetic herbicides seemed to be doing the trick… for now, at least. But we can’t rely on that forever.

  Carefully he laid down three of the lamps and eased the fourth into position just past the open hatchway, in the tunnel proper. He had to hunt for the right electrical socket, and found it at last, partly hidden under a filmy cobweb of multicolored threads. These had to be brushed aside with his boot before he could plug the unit in and set the timer.

  “Hello. Testing.” He tapped the little headset microphone that extended from under his wool cap.

  “Lintz speech-routing to Spacer Osborn’s headset, please connect for conversation.” He knew there were more economical ways to ask the main computer to link him to Carl—he had seen the spacers chirp routing instructions in less time than it took to do a good hiccup—but he had forgotten the correct protocols. This way, at least, the machines were sure to understand.

  A short pop, then a hissing carrier wave.

  —Lintz, Osborn. What’s up, Saul?—

  The reply in his left ear was spare, to say the least. But spacers were like that. Terseness didn’t necessarily mean anything.

  “Carl, Joao Quiverian and I have finished checking out sleep slot one. Destroyed twenty-three infestations. Can’t be sure we didn’t overlook a few minor ones, but the slots don’t appear to be in immediate danger anymore.”

  Saul quashed the tickling sensation of a threatening sneeze. He spoke quickly.

  “I took an hour and went up to the surface to rummage through the storage tents, to see if there was anything we might use. There were a couple of dozen halogen-hydrogen space-signal lamps that gave me an idea. I figure we can place some at critical passage junctions and set them to bathe an area, at intervals, with intense ultraviolet. Who knows? It might slow the beasts down a bit.”

  There was a pause before Carl answered again.

  —Sounds reasonable. But we don’t want to blind or burn anybody.—

  Saul nodded. “I thought of that. Brought down goggles and sun salve for the hall gangs. Also, I tore apart an unused mech-controller board and pulled out some type-five malfunction alarms… you know, the ones that go brrr-ap! brrr-ap!”

  The carrier wave came on again, suddenly. It sounded like coughing until he realized Carl was laughing at his rendition. He grinned.

  “Anyway, an alarm will go off a minute before each lamp is triggered. Both will stay on for five minutes on the hour.”

  —Good enough. Where’ll you set ’em up?—r />
  “At the entrances to each sleep slot, just outside Central, and along Shaft One. I’m not sure if we have enough power or bulbs to do more, so—”

  Carl interrupted, —Fine, Saul. But I want to try them on something else, first. I’ll send Vidor and Ustinov down to pick up the goggles and half-a-dozen lamp.—

  “What’s up?”

  There was another brief pause. Then Carl confided.

  We’re about to mount an assault on the purples that have surrounded the power plant. Maybe your idea will help there.

  “Uh, I sure hope so.”

  —Yeah. Anyway, give Garner a few more minutes, then wake him. Tell him he’s to come back with Vidor. We’re going to need every hand on this one. Osborn out.

  The carrier wave clicked off. Saul stood very still for a moment, shaking his head.

  The power plant. I had no idea.

  No wonder Virginia had been so terse the last time he had called. He’d felt like a silly teenager, wondering if she still loved him, because she had blown him a hurried kiss and hustled him off the line.

  She probably had her hands full right now, preparing mechs to help Carl. If any of a dozen conduits leading into or out of the pile were clogged by organic matter, it could trip an automatic shutdown. That, in turn, could mean the end for all of them.

  He ought to give the lamps a brief test before sending a set to Carl. No sense in burdening the man with a clutter of useless equipment if the things wouldn’t do more than give the Halleyforms a suntan. Saul slipped on a set of goggles and bent to turn on the timer.

  The sudden brrr-ap! of the tiny alarm made him jump, even though he was ready for it. Then came a faint pop as the lamp suddenly filled the amber tunnel with sharp, actinic light. Even under the goggles, Saul blinked and had to turn away.

  When he next looked, he realized that something funny was going on. All at once every surface appeared to be coated in a shimmering haze. The walls themselves seemed to ripple and crawl, like the fur on a caterpillar’s back. At first he thought it was an optical illusion—an effect of the weird coloration and glare. Then he realized.