The Heart of the Comet

by David Brin

  As the ferry pulled outward the twin tails—one of dust and the other of fluorescing ions— stretched away, foreshortened pale remnants of the glories that had enthralled Earth only two months ago. Ragged streamers forked out toward Jupiter’s glowing pinpoint. Oblivious, Carl stretched back and dozed while the ferry rose to meet the Edmund.

  When they clanged into the lock, he peeled off his suit and coasted toward the murmuring gravity wheel at the bow. He climbed down one of the spoke ladders and stumbled out into the unfamiliar tug of one-eighth G, feeling bone-deep weariness descend with the coming of weight.

  Sleep, yes, he thought. Let it knit up whatever raveled sleeve he had left.

  Virginia came first, though. He hadn’t seen her in ages.

  She was in her working module, of course, halfway around the wheel. She seldom left the thing nowadays. The door hissed aside. When he slipped into the spherical world of encasing memory shells there was an almost cathedral-like hush, a sense of presence and humming activity just beyond hearing. He sat down quietly next to her cantilevered chair, waiting until she could extract from interactive mode. Tapped into channels through a direct neural link and wrist servos, she scarcely moved. She had to know he was there, but she gave no sign.

  Her slim body occasionally fidgeted and jerked. Like a dog dreaming, he thought, and trying to run after imaginary rabbits.

  Her long, half-Polynesian features were pointed toward the banks of holographic displays suspended above her, and her eyes never even flicked to the side to see him. She gazed raptly at multiple scenes of movement, sliding masses of ever-flickering data, geometric diagrams that shifted and evolved, telling new tales.

  He waited as she worked through some indecipherable problem. Her long face momentarily tightened, then released as she leaped some hurdle. She had delicate, high cheekbones, too, like Umolanda. Like a third of the expedition’s crew, the Percells, products of Simon Percell’s program in genetic correcting of inherited diseases. Carl wondered idly if fineboned, aristocratic features were traits the DNA wizard had slipped in. It was possible; the man had been a genius. Carl’s own face was broad and ordinary, though, and he had been “developed,” as the antiseptic jargon had it, within a year of Virginia. So maybe Simon Percell had taken such care only with the women. Given the gaudy stories told about the man, he couldn’t rule out the possibility.

  By anyone’s definition, Virginia Kaninamanu Herbert was clearly a successful experiment. A Hawaiian mixture of Pacific breeds, she had a swift, quirky intelligence, deliciously unpredictable. There was restless energy to her eyes as they moved in quick darting glances at the myriad welter before her. Below, her mouth was a study in quiet immersion, slightly pursed, thoughtful and pensive. She was not, he supposed, particularly attractive in the usual sense of the term; her long face gave her a rangy look. The serene almond smoothness of her skin offset this, but her forehead was broad, the mouth too ample, her chin was stubbed and not fulsomely rounded as fashion these days demanded.

  Carl didn’t give a damn. There was a compressed verve in her, a hidden woman he longed to reach. Yet all the time he’d known her she had stayed inside her polite cocoon. She was friendly but little more. He was determined to change that.

  On the main screen, obliquely turned girders fitted together in precise sockets. The frame froze. Done.

  Abruptly Virginia came alive, as though some fluid intelligence had returned from the labyrinths of her machine counterpart. She stripped the wrist inputs. The white socket for her neural connector flashed briefly as the tap came off and she fluffed her hair into shape.

  “Carl! I hoped you’d wait for me to finish.”

  “Looks important.”

  “Oh, this?” She waved away the frames of data. “Just some cleanup work. Checking the simulations of docking and transfer, when we take everybody down. There’ll be irregularities from random outgassing jets, and the slot boats will have to compensate. I was programming the smarter mechs for the job. We’re ready now.”

  “It’ll be a while.”

  “Well, a few more days… Oh, yes.” She suddenly became subdued. “I heard.”

  “Damn bad luck.” His mouth twisted sourly.

  “Fatigue, I heard.”

  “That too.”

  She reached out and touched his arm tentatively. “There was nothing you could do.”

  “Probably. Maybe I shouldn’t have let her go down that hole right after Kato bought it. Thing like that, shakes you up, screws up your judgment. Makes accidents more likely”

  “You weren’t senior to her.”

  “Yeah, but—”

  “It’s not your fault. If anything, it’s the constraints we work under. This timetable—”

  “Yeah, I know.”

  “Come on. I’ll buy you some coffee.”

  “Sleep’s what I need.”

  “No, you need talk. Some people contact.”

  “Trading arcane jokes with that computer crowd of yours?” He grimaced. “I always come out sounding like a nerd.”

  She flexed smoothly out of her console couch, taking advantage a of the low gravity to curl and unwind in midair. “Not at all!” Something in her sudden, bouncy gaiety lifted his heart. “Blithe spirit, nerd thou never wert..”

  “Mutilated Shelley! God, that’s awful.”

  “True, though. Come on. First round is on me.”

  SAUL

  To most people the creature would seem hideous. Vaguely globular, specked with yellow and ocher spots and spiky protrusions all around, it had the sort of looks only a particularly indulgent mother could love.

  Or a stepfather, Saul Lintz thought.

  Millions of the tiny, ugly things darted about in the crowded confines of a single, glinting drop of saline water, beaded by surface tension into a high, arching meniscus on the glass microscope slide.

  Saul played the fiber optic controls until his magnifier zoomed in on a single cyanute. “There we are,” he muttered softly. “You’ll do as a test subject, my lad.”

  He pressed a trigger and the cytology instrument took over following the tiny microbe, automatically tracking it wherever it swam within its little universe.

  The creature was a pulsing mass of tiny, rainbowed cilia that rippled faster than the eye could follow. But Saul knew the thing anyway, to its smallest part. He could imagine every mottled, microscopic component down past where the instrument could not go—to the level of acids and bases, of sugars and finely balanced lipid barriers.

  It darted to and fro amid the thousands of other rough, rippling cells, seeking what it needed to survive.

  Not unlike us, Saul thought. Only our search has brought us humans half a billion miles from home.

  He rubbed his eyes and bent forward in a habit from long-ago days, when one still occasionally peered through cold glass lenses instead of letting the machines do all the hard work. Relax, Saul told himself. There’s no need to crane over the screen.

  Even here, in Edmund’s slowly spinning gravity wheel, there wasn’t enough of a pull to fight against. One had to keep loose, or expend enormous energy just to stay still.

  Only half of the screens and holo displays in the biology unit brimmed with light. In a dozen other dark faces Saul’s own pale image was reflected… thick eyebrows above a generous nose, and lines that most people, on meeting him, guessed came of a lifetime spent smiling.

  Only those who knew Saul well—and they were few these days—understood the true source of those craggy indentations: a stoicism that warded off the pain of many, many losses.

  The creases stood out now as Saul’s blue eyes narrowed it concentration. Delicately touching a hand controller, he brought a hollow sliver of metal down into the little ball of salty water on the microscope slide. On the main holo screen the image of the tiny needle seemed to loom like a javelin as computers guided it toward the chosen test subject.

  “Come on, meshugga,” Saul muttered as the microbe tried to dart away. “Hold still for
Papa.”

  The cyanute was less than fifty microns across, so small and innocuous that its ancestors had lived peacefully in human bodies for millions of years of quiet symbiosis, until they were discovered only a generation or so ago. For Saul the little creature contained as many wonders as the huge comet commanding such attention outside.

  The main vision wall of the lab had been left tuned to a view of Halley, not as the comet looked now—a slowly ebbing cloud of banked fluorescence surrounding a six-mile chunk of dingy snow—but as it had been only months before, in all its brief glory, streaking past the sun at half the Earth’s orbital distance, its ion tail flapping in the protonic breeze.

  They were well matched in beauty—the titanic, cosmic messenger that was to be their home for most of a century and the microscopic wonder that had made the sojourn possible. Still, it was no surprise that, of the two, Saul concentrated on the tiny living thing drifting in the little glob of water.

  After all, he had made it.

  Sh’ma Yisrael… he reminded himself. There is but one God—even though he should place his tools in our hands—tools to shape life and forge worlds. He is only stepping back to see what we will do with them.

  In Saul’s line of work he found it wise to remember that, from time to time.

  When the needle had approached to within a cell’s width of the subject, Saul spoke a word and triggered the test sequence. A small, indistinct puff disturbed the water near the needle’s tip, where tiny traces of hydrogen cyanide solution spurted forth.

  No more than a scattering of molecules was involved, yet the tiny organism reacted nearly instantly. Its cilia erupted in a sudden spasm of activity and the creature sprang forward…

  Forward, toward the needle. It engulfed the tip, throbbing with seeming eagerness.

  So far, so good. Saul would have been surprised if it had behaved differently. The cyanutes had been thoroughly tested on Earth before the mission to Halley’s Comet was approved. No factor was more important to the success and health of 410 brave men and women than these little creatures.

  Confident he was. But life—even specially gene-tailored life—had a way of changing when you least expected it. The survival of all those people depended on the tiny “nutes” working as planned. He had led the team that designed them, and he did not intend to allow any failures. There were more than enough ghosts already in his life. Miriam, the children, the land and people of his youth… and, of course, Simon Percell.

  Poor Simon. All too well he recalled how one mistake had ruined his friend’s life and nearly everything he had worked to accomplish. Keep reminding me, Simon. Keep reminding me of the dangers of playing God.

  All the HCN was gone now, according to the displays, sucked up by the eager organism. Saul nodded in satisfaction. Every human being on this mission had millions of cyanutes living in his or her bloodstream and in the little alveoli air sacs that made up their lungs. This sample, taken at random from one of the crew, had just demonstrated that it would do its main job—sop up any trace of deadly, dissolved cyanide gas before the stuff could get near its host’s red corpuscles. Another puff of dissolved gas proved its ability to gobble carbon monoxide before that chemical could bind to human hemoglobin.

  Saul touched off the next stage in the test. Minute traces of a new compound swirled into the saline bubble. This time the little microbe on the screen quickly withdrew from the needle, curling almost as if it had been stung. Cyanide and CO were fresh grazing to this creature, but human tissue factors appeared to be a definite no-no.

  Again, good news. The second test showed that the cyanute was totally disinclined to look on human cells as meat.

  So much for the basics. There were countless other things to check. Saul mentally ran down a list as he triggered the sequencer to begin the automatic phase of the test program.

  … Self-limiting reproduction, benign acceptance by the human immune system, pH sensitivity, a voracious appetite for other potential cometary toxins…

  It wasn’t so much a catalog of attributes as a litany of challenges met and conquered. Saul couldn’t help feeling proud of his small team back on Earth, which had had to overcome prejudice, bureaucracy, and undisguised superstition to do this work. In the end, though, they had created a wonder-a new human symbiont.

  Cyanutes would be a permanent, benign part of every man and woman on the crew for the rest of their lives… and perhaps, he dared imagine, a part of the human animal from now on, like the intestinal flora that had always helped him digest his food and the mitochondria within his cells that burned sugars for him, converting them into usable energy.

  “Who can compare with thee, oh Lord…” he whispered wryly, teasing himself for his ineradicable corner of hubris. Saul had long ago concluded that he and God would have to be patient with each other. Perhaps the universe was not conveniently set up for either of them.

  He watched the test results unfold on the screen—all nominal, nearly perfect—until a soft squeak announced the opening of the bio-lab portal behind him.

  “So! We are poking away at our pets again, Saul? You just cannot leave them alone?”

  He didn’t have to look up to know the voice of Akio Matsudo. “Hello ’Kio.” He waved without turning around. “Just double-checking. And everything looks fine, thanks. Aren’t they lovely critters?”

  He smiled as the spry, tall Japanese physician came alongside and made a sour look. The chief of Mission Life Sciences had never disguised his opinion of Saul’s “critters.” They were necessary—utterly vital to the success of their seventy-eight-year voyage. But poor Akio had never come to see their more aesthetic side.

  “Ugh,” Matsudo commented. “Please do not remind me of the infestation even now swarming in my bodily fluids. Next time you wish to inject me with alien parasites—”

  “Symbionts,” Saul corrected quickly.

  `—against which my body has no immune capability whatsoever—next time I will make the incision myself—from crotch to sternum!”

  Saul could only grin as Matsudo ’s serious mug broke and the man actually giggled. It was a “kee-kee-kee” sound that spacers had already mimicked into a sort of clarion call below decks. Akio frequently made such light jests about the traditions of ancient Japan.

  Perhaps it was similar to the way Saul dropped Yiddishisms into his speech now and then, although he had learned the language only a decade ago. It’s a proper dialect for exiles, he thought.

  “What have you got there, ’Kio?” He pointed at a flimsy sheet in the other’s hand.

  “Ah. Yess.” Matsudo tended to slur his sibilants. “Even as we are speaking of immune systems, I have come to ask you to go through the stimulants inventory with me, Saul. I believe that it is time to release an attenuated disease into the life-support system.”

  Saul winced. He never looked forward to this.

  “So soon? Are you sure? Four-fifths of the expedition is still frozen aboard the Sekanina and the other freighter tugs. All we have awake now are the Edmund crew and support staff.”

  “All the more reason.” Matsudo nodded. “Thirty spacers have been living together on this cramped ship for more than a year. Another forty have been out of the slots for two or more months, as we got closer to the comet. All of the colds and minor viruses they brought with them when they departed Earth have run their course by now.

  “I’ve done a parasite inventory, and have found that more than three-quarters of the ambient pathogenic organisms have already gone extinct! It is time to release a new challenge.”

  Saul sighed. “You’re the boss.” Actually, the entire bio committee was supposed to pass on immune challenges. But reminding Akio would only offend him. The procedure was routine, anyway.

  Still, Saul’s nose already itched in unhappy anticipation.

  He reached over to the bio-library console and punched out a rapid code. A page of data appeared in space before a black backdrop.

  Saul nodded at the glowing green le
ttering. “There is a lovely array of nasty bugs at your disposal, Doctor. With what plague do you wish to infect your patients? We have chicken pox, fox pox, attenuated measles…

  “Nothing so drastic.” Matsudo waved. “At least not so soon.”

  “No? Well, then there’s impetigo, athlete’s foot… :’

  “Amaterasu! Heaven forfend, Saul! In this dampness? Before the comet-tunnel habitats have been set up and the big dehumidifiers are working? You know how the navy feels about fungus aboard a spaceship. Cruz would have our—”

  He stopped abruptly and grinned lopsidedly. “Ha ha. Very funny, Saul. You are pulling my leg, of course.”

  Saul had known Matsudo casually, from scientific conferences and by reputation, for many years. But the man was still somewhat of an enigma to him. For instance, why had he volunteered to come on this mission? Of all the types who would sign up to leave Earth, spend seventy-three years of a seventy-eight-year mission in slot sleep, and return to a world grown alien and strange, which category applied to Akio? Was he an idealist, following Captain Miguel Cruz’s dream of what the mission might mean to mankind? Or was he an exile, like so many on this expedition?

  Perhaps, like me, he’s a little of both.

  Matsudo ran a hand through his lustrous black hair, as thick as any youth’s. “Just pick me out a head-cold virus, will you be so kind, Saul? Something that will challenge the crew enough to keep up their antibody production and T cell counts. They needn’t even notice it, for all I care.”

  Saul spoke a chain of letters aloud, and a new page appeared. “The customer’s always right,” he ruminated aloud. “And you’re in luck! We seem to have eighty varieties of head cold on sale.”