The Heart of the Comet

by David Brin

  Saul shrugged. “I’ve found signs of infection, all right, and foreign protein factors, out little more definite than that.” He had come to realize, at last, that he would probably never track down the pathogen, or pathogens, without a lot more data. He needed to know more in a basic sense about Halley lifeforms.

  If Nick wouldn’t let him near the patients, then he should be looking elsewhere! What Saul wanted most was to get out into the halls and see for himself… to collect samples, build a data base, and find out what had killed his friend. But this damned quarantine…

  He turned his head and lifted a tissue before sneezing. His ears rang and his vision swam for a moment.

  Well, at least Jim Vidor didn’t seem to feel in much danger, visiting a presumed Typhoid Mary. He had backed away at the sudden eruption, but as soon as Saul’s composure returned, the spacer stepped back up to look over his shoulder.

  “Got any idea what it is, Dr. Lintz? This new stuff was clustered all around the inlet pipes on B level, and I’m afraid it may turn into as big a problem as that green gunk, if it plugs up the dehumidifier.”

  Nick and I are scared by the tiny things… microscopic lifeforms that kill from within. But spacers have other concerns. They worry about machines that get clogged, about valves that refuse to close or open, about air and heat and the sucking closeness of hard vacuum.

  “I don’t know, Jim. But I think…”

  The screen whirled and a tiny cluster of threads leaped into magnified view. Saul cleared his throat and mumbled a quick chain of key-word commands. Abruptly, a sharp beam of light lanced forth, evaporating a tiny, reddish segment into a brilliant burst of flame. One of the side displays rippled with spectra.

  “Nope. I guess it can’t be a mutated form of something we brought with us, after all. It has to be native.” Saul rubbed his jaw as he read an isomer-distribution profile. “Nothing born of Mother Earth ever used a sugar complex like that.” He wondered if it even had a name in the archives of chemistry.

  Vidor nodded, as if he had expected it all along. Innocence, sometimes, leaps to correct conclusions when knowledge makes one resist with all one’s might.

  Saul, too, had suspected, on seeing the stuff for the first time. For it looked like nothing Earthly he had ever seen. But he had found it hard to really believe until now. Microorganisms were one thing he could rationalize that, particularly after seeing JonVon’s wonderful simulation of how cometary evolution could occur. Primitive prokaryotic microbes, yes. But how, in God’s perplexing universe, did there ever get to be something so complex… so very much like a lichen, deep under a primordial ball of ice?

  I never really believed Carl Osborn’s story of macro-organisms out in the halls, he confessed to himself. I guess I just pushed it out of my mind, denigrating whatever he had to report, answering hostility with hostility. Instead I kept busy doing routine stuff, studying microbes, ignoring the evidence that something far larger was going on here.

  Of course, Carl had not exactly cooperated, either. They had not seen each other since that fateful morning in the sleep slots. And Carl had never sent the samples Saul had asked for. Small wonder he had been so glad when Jim Vidor took the initiative.

  “For want of a better word, Jim, I’d have to call this thing a lichenoid… something like an Earthy lichen. That means it’s an association creature, a combination of something autotrophic—or photosynthesizing—like algae, with some complex heterotroph like a fungus. I’ll admit it’s got me stumped. Though. Nothing this complicated ought to—”

  “Do you know of any way to kill it?” Vidor blurted. His eyes darted quickly to the screen, where the fibers slowly moved under intense magnification.

  Suddenly Saul understood.

  Vidor is an emissary. Carl couldn’t get any useful help out of Malenkov. Of course he wouldn’t come right out and approach me. Not as angry as he is over Virginia.

  Another wave of dizziness struck and Saul gripped the edge of the table, fighting to hide the symptoms.

  Maybe Nicholas is right. Maybe this isn’t just another flu bug. Perhaps I’m already a goner. If so, isn’t Carl right too? What have I to offer Virginia, other than, maybe, a chance to get infected if I ever do get out of quarantine?

  What right have I to stand in between Carl and her, if I’m doomed anyway?

  Oddly, the idea that he might really be dying made Saul’s heart race. He had supposed himself free of any fear of death for at least ten years. But now the mere idea made his skin tense and his mouth go dry.

  Incredible. Did you do this for me, Virginia? Did you give me back the ability to feel fear? Fear of losing you?

  It was a wonder. Saul became aware again of Jim Vidor, eyes blinking down at him from above his mask, and smiled.

  “Tell Carl I’ll make a deal with him. He gets me loose of this fershlugginner prison, so I can go out and see what’s happening in person. In return, I’ll do what I can to help keep gunk out of his pipes. Even if all I can do is swing a sponge with the rest of you.”

  Vidor paused for a moment, then nodded. “I’ll tell ’im, Dr. Lintz. And thanks. Thanks a lot.”

  The spacer spun about and whistled a quick code, so the door was open by the time he sailed through into the hallway. Saul watched the hatch close. Then he looked back up at the tangled bird’s nest of alien threads on the screen.

  A part of him wondered if it was morally legitimate to go looking for ways to fight the indigenous lifeforms that were causing the spacers such grief. After all, Earthmen were the invaders here. They had arrived from a faraway world as much different from this one as Heaven supposedly was from Hell. Nobody had invited the humans. They had just come—as they always did.

  As we have always meddled, eh, Simon?

  Saul shrugged. The little moralist voice was easy to suppress, as was the fear that he was dying. He would fight, and he would live. Because for the first time in a decade he had someone to fight and live for.

  That’s right, he thought ironically. Blame it on Virginia, you buck-passer.

  He stopped to wipe his nose, then dropped the handkerchief into the sterilizer. Saul popped another cold pill into his mouth.

  Smiling grimly, he reached forward and turned up the magnification.

  “Okay, buster. You’ve got me curious. I want to find out all about you. If we’re going to have to fight, I want to know just what makes you tick.”

  He put the Tokyo String Quartet on the vid wall, recorded by cameras and pickups only feet away from the famous chamber group. They played Bartok for him as he twisted dials, spoke into a recorder, smiled grimly, and occasionally sneezed.

  VIRGINIA

  See the mechs dance, see the mechs play, Virginia thought moodily, halfway through a reprogramming. God, I wish they’d go away.

  It had been hours on hours now and the jobs were getting harder. She lay stretched out, physically comfortable but vexed and irritated by the unending demands. She tried out a new subroutine on a mech filling her center screen. It turned, approached a phosphor panel. Careful, careful, she thought—but she did not interfere. A mistake of a mere centimeter would send the mech’s arm poking through the phosphor paint, breaking the conductivity path in that thin film, dimming the panel. The virtue of phosphors lay in the ease of setup—just slap on a coat of the stuff, attach low-voltage leads at the corners. and you had a cheap source of cold light. The disadvantages were that they had little mechanical strength and tended to develop spotty dim patches where the current flowed unevenly. A mech could bang one up with a casual brush.

  Which this one proceeded to do, as she watched. It tried to spot the growing green gunk and wipe it away with a suction sponge. Partway across the panel, though, the arm swiveled in its socket and dug into the phosphor with a crisp crunch. The radiance flickered, dimmed.

  Damn. Virginia backed the mech away and froze it. Then she plunged back into the subroutine she had just written, trying to find the bug that made the mech arm screw up at that cruc
ial step.

  —Virginia ! I need five more in Shaft Four, pronto! —Carl’s voice broke in.

  She grimaced. “Can’t have them! All full up.” She kept moving logic units around in a 3D array, not wanting to let the structure of the subprogram slip away. Just a touch here, a minor adjustment there, and—

  —Hey, I need them now!—

  “Shove off, Carl. I’m busy.”

  —And I’m not? Come on, the gunk is eating us alive out here.—

  “We’re overextended already.”

  —I’ve got to have them. Now!—

  It was hopeless. She punched in a last alteration and triggered the editing sequence. On a separate channel she sent, “JonVon, take a look at this. What’s the problem? I’m too dumb to see it.”

  PERMISSION TO INTERROGATE MECH AND ADJUST ONBOARD SOFTWARE?

  That was a little risky; JonVon was great at analysis, but had not had much experience working directly with mechs. What the hell, this is a crisis. “Sure.”

  —Virginia ? Don’t duck out on me.—

  “I’m here. I feel like a short-order cook, trying to switch these mechs around. Between you and Lani and Jim, there’s no time to reprogram these surface mechs for tunnel work.”

  Carl’s voice muted slightly. —Well, sorry, but I’m facing a bad situation here. This stuff is spreading fast—must be more moisture in the air here. We may have to clean them out in vac. That’s tougher.—

  “I know, I know” Carl always patiently explained why he needed help, as if she simply didn’t understand.

  She switched to another channel, surveyed the situation near Lock 3, and issued a quick burst of override orders directly through her neural tap to stop an overheating valve from melting a hole in the vac-wall. Then back to Carl: “Look, I can’t do it right now.”

  —How come?—Was that a petulant, irritated tone? Well, the hell with him.

  “Because I’m up to my ass in alligators!” she shouted, and broke the connection.

  It felt good.

  CARL

  It began with a high, thin whistling.

  Carl was working at a pipe fitting—cursing the green gunk that made it slippery—when he heard the sound, at first just a distant, reedy whine. He was far out along Shaft 3, near the surface lock, and assumed that the single, persistent note came from somebody working further in, toward Central.

  He was alone because they were so low on manpower. Carl had been working with one of Virginia ’s reprogrammed mechs, but avoided that if possible. It got in the way of the job when the machine spoke with her distinctive lilt.

  The first awakenings were due to “thaw out” next Tuesday, and he hoped that would help with the chores. The gunk was slimy, foul, and persistent; he hated it.

  And those damned threads that get caught in the air vents. Maybe Jim Vidor’s right, I should let Saul out of quarantine, have him study this stuff up close.

  If he had been with a partner he might have been less meditative, and heard it sooner. The sound kept on while he tightened up the joint with his lug wrench, the rrrrrttttt rrrrrttttt rrrrrttttt sending vibrations up into his shoulders.

  Carl lifted his head. He felt a breeze.

  There was always circulation of air in space, driven by booster fans if temperature differences didn’t give enough convection. But not this far from Central, not a steady feather-light brush past his ears.

  He stopped, listened. The same steady note. It came from below, downshaft, toward Central.

  Then his ears popped.

  He reeled in his tools and pushed off, all in one smooth uncoiling motion. A burst from his jets and he plunged inward. Phosphors dotted the shaft with pools of yellow-green light every hundred meters; automatically he used them to judge his speed, to keep from picking up momentum he wouldn’t be able to brake. Smears of green gunk covered some of the phosphors, growing on the wan energy they put out.

  He passed tunnels that ran horizontal, 3B, 3C, and 3D, but the sound wasn’t coming from them. Coming toward 3E, he slowed because the whistling was getting louder and a steady suction was trying to draw him downward. Carl had always hated high-pitched noise and this was now shrill, grating. He was searching for a split seam in the insulation but wasn’t at all ready for what he found.

  Worms! He blinked, stunned.

  Purple snake-like things oozing, wriggling. Moist, slick, waving slowly, ringing 3E’s entrance. It was like a living mouth calling with a cutting siren wail, the wind moaning and tugging and sucking him toward the beckoning purple cilia that eagerly flexed and yearned and stretched out toward him—

  He fumbled at his jets and pulsed them hard, backward. Wind swirled by him, sending his tool lines streaming away, tearing the wool cap from his head, ruffling his hair. He twisted and caught a handhold in the shaft wall. The noise was deafening now and he knew he was getting rattled by it.

  What the hell—!

  He ripped open his emergency pocket and fished out a plastisheet helmet. It took a long moment to tuck it into the O-ring seal in his skinsuit. I haven’t practiced this drill in a long time.

  It caught. He pulled the FLOOD bottle tab. The bubble expanded with a reassuring whoosh of air. That provided some sound insulation, but not much. Not enough.

  “It’s at Shaft Three, Tunnel E,” he sent over the emergency channel. “Three E, Three E, Three E. Bad. Whole area around the collar is ruptured.”

  A faint voice called in his bonephone, —… can patch with spray foam? Got some on its way.

  “I doubt it. Something… something’s broken through. This sure isn’t just a rip.”

  Carl bit his lip. He didn’t know how to describe it. The team would take only a few minutes to get here, but the shaft was losing torrents of air.

  The purple…things…must’ve broken through to a crevice leading up to the surface.

  He launched himself across the shaft. The wind blew him several meters before he hit the far side and managed to hook a temporary clip into the insulation. He hung on and watched the nearest of the purple worms twist and pulsate, rivulets of ocher sweat running down from the pointed tip. The wind blew the drops away, sucking them back into the gaping hole that ringed the base of the worm.

  The horrible thing bloated, contracted, bloated again—each time prying the insulation wider, admitting more of it into the shaft. The nearest was at least a meter long and visibly growing, convulsing in a slow agony of swell and clench, swell and clench. Its maw glittered with what looked like crystals of native iron.

  They’re after the green gunk, he realized as the worms pressed against the layers of mosslike growth within their reach. They seemed to absorb it directly. They’re grazing on the stuff!. And sucking threads out of the air.

  Around the aluminum and steel collar of 3E’s entrance Carl counted thirteen of them. He played out some line and the howling gale sucked him down, toward one of the eyeless, slime-sweating things.

  Carl clenched his teeth. He was breathing bottled air now but he’d swear he could smell it—cloying, thick, humid, like ripe, moldering leaves.

  He unhooked his laser cutter, thumbed it to max, and fired at one. The beam drove a thin red line straight through it… with no significant effect.

  He made the next bolt last longer and sliced the thing off a few centimeters above the base. A spray of purple-red whipped away into the wind. The top wobbled and fell aside, then tumbled slowly away.

  More fluid seeped from the wound and then it began to film over. As Carl watched the thing began growing a thickening crust. The new matter had a rich, glossy purple skin like an eggplant. Then it began to thrust outward, sideways, outward again—onward, into the shaft, the wound only a momentary interruption.

  Carl felt the hair rise in prickly fear along the back of his neck.

  —… it like now? Repeat, can’t pick you up, want to know…—

  The rest was lost. Carl could see no one in the shaft. Where were they?

  He pulled his patch gun fro
m its holster on his left calf. It was intended for small work, but he couldn’t think of anything else to do.

  To get closer he played out another meter of line, then hastily drew some back in as the burgeoning thing waved his way. Could it sense him? Without eyes or any visible organs? Maybe his body heat. He wasn’t going to take any chances.

  The patch gun spat a wad of yellow gum at the hole. It splattered over the opening, spreading quickly as the long chain molecules grasped for the maximum surface area to bond. The suction bowed it inward but the yellow patch held.

  For almost a minute. Then the worm butted against the cloying yellow film, wrenched, flexed—and shook it free. The wind tore at the loose edge. It flapped futilely like a ragged flag.

  “We’ll need the big stuff,” Carl sent. “Bring all we got.”

  —… can’t hear… any other measures… take to be sure…—

  “Yeah. Seal all locks. Everywhere.”

  —… don’t under… we’re sending all…—

  “If we run out of sealant, the locks are our only backup.”

  And if that fails, he thought, we’ll have to live in suits.

  Ten minutes later, that didn’t seem so unlikely.

  Only Lani and Samuelson and Conti were available to help right away; crew was stretched thinly everywhere. Lani was a spacer, quick and smart, but the other two had been pressed into jobs they didn’t know.

  They worked as fast as possible. Chopping the tendrils was simple, but more pushed in before the sealant could harden. Carl and Samuelson discovered that to make any progress at all, they had to get close into the tip in the insulation and clear out the whole area, cutting all the way back to the ice.

  —Got to slice it clean away,—Samuelson said. The large man licked his lips nervously. —Damnedest stuff I ever saw.—

  “Watch out there with that torch, you’re close to the ice.” Carl had to hold Samuelson on a rope to keep the man from being sucked directly against the hole. The team had rigged a set of linchpin stays and lines to keep the howling wind from plucking them off the shaft walls. Now the shrill, hollow shriek slowly dulled as the air in Shaft 3 finally ran out.