by David Brin
“Relax.” The voice was back to business. Probably led by the zep mechanic.
“You’ll need a command word. Touch that nub in the middle to get attention and say ‘Cinnamon.’”
“Cinnamon?”
It was only a query, but the barrier reacted instantly. With a faintly squishy sound, it dilated and the stringy stepladder resumed its programmed journey, carrying her upward.
Aboard old-time zeps, like the Hindenburg, the underslung gondola had been devoted mainly to engines and crew, while paying passengers occupied two broad decks at the base of the giant dirigible’s main body. The Spirit of Chula Vista had a similar layout, except that the gondola was mainly for show. Having climbed above all the sections designed for people and cargo, Tor now rode the throbbing ladder into a cathedral of lifter cells, each of them a vast chamber in its own right, filled with gas that was much lighter than air.
Hundreds of transparent, filmy balloons—cylindrical and tall like Sequoia trunks—crowded together, stretching from the web-floor where she stood all the way up to the arched ceiling of the Spirit’s rounded skin. Tor could only move among these towering columns along four narrow paths leading port or starboard … fore or aft. The arrow in her specs suggested port, without pulsing insistence. Most members of the smart-mob had never been in a place like this. Curiosity—the strongest modern craving—formed more of these ad hoc groups than any other passion.
Heading in the suggested direction, Tor could not resist reaching out, touching some of the tall cells, their polymer surfaces quivering like the giant bubbles that she used to create with toy wands, at birthday parties. They appeared so light, so delicate.…
“Half of the cells contain helium,” explained the voice, now so individualized that it had to be a specific person—perhaps the zep mechanic or else a dirigible aficionado. “See how those membranes are made with a faintly greenish tint? They surround the larger hydrogen cells.”
Tor blinked.
“Hydrogen. Isn’t that dangerous?”
Her spec supplied pics of the Hindenburg—or LZ 129—that greatest and most ill-fated ancient zeppelin, whose fiery immolation at Lakehurst, New Jersey, marked the sudden end of the First Zep Era, in May 1937. (Facts scrolled along the bottom, lured in by attention cues.) Once ignited—how remained controversial—flames had engulfed the mighty airship from mooring tip to gondola, to its swastika-emblazoned rudder, in little more than a minute. To this day, journalists envied the news crew that had been on-hand that day, with primitive movie cameras, capturing onto acetate some of the most stunning footage and memorable imagery ever to accompany a technological disaster.
Nowadays, what reff or terr group wouldn’t just love to claim credit for an event so resplendent? So attention-grabbing?
As if reading her mind, the voice lectured.
“Hydrogen is much lighter and more buoyant than helium. Hydrogen is also cheap and readily available. Using it improves the economics of zep travel. Though of course, care must be taken.…”
As Tor approached the end of her narrow corridor, she encountered the trusswork that kept Spirit rigid—a dirigible—instead of a floppy, balloonlike blimp. One girder made of carbon tubes, woven into an open latticework of triangles, stretched and curved both forward and aft. Nearby, it joined another tensegrity strut at right angles. That one would form a girdle, encircling the Spirit’s widest girth.
Tracking Tor’s interest, her spec spun out statistics and schematics. At eight hundred feet in length, Hindenburg had been just 10 percent shorter than the Titanic. In contrast, the Spirit of Chula Vista stretched twice that distance. Yet, its shell and trusswork weighed half as much.
“Naturally, there are precautions,” the voice continued. “Take the shape of the gas cells. They are vertical columns. Any failure in a hydrogen cell triggers a pulse, bursting open the top, pushing the contents up and out of the ship, skyward, away from passengers, cargo, or people below. It’s been extensively tested.
“Also, the surrounding helium cells provide a buffer, keeping oxygen-rich air away from those containing hydrogen. Passenger ships like this one carry double the ratio of helium to hydrogen.”
“They can replenish hydrogen en route if they have to, right? By cracking water from onboard ballast?”
“Or even from humidity in the air, using solar power.
“And yes, the readouts show unusual levels of hydrogen production, in order to keep several cells filled aboard the Spirit. That’s why we asked you to come up here. There must be some leakage. One scenario suggested that it might be accumulating in here, between the cells.”
She pulled the omnisniffer—a phone attachment—from her purse and began scanning. Chemical sensors were all over the place, naturally, getting cheaper and more acute all the time—just when the public seemed to want them. For reassurance, if nothing else.
“I’m not detecting very much,” she said. Tor wasn’t sure how to feel—relieved or disappointed—upon reading that hydrogen levels were only slightly elevated in the companionway.
“That confirms what onboard monitors have already shown. Hardly any hydrogen buildup in the cabins or walkways. It must be leaking into the sky—”
“Even so—” Tor began, envisioning gouts of flame erupting toward the heavens from atop the great airship.
“—at rates that offer no danger of ignition. The stuff dissipates very fast, Tor, and the Spirit is moving, on a windy day. Anyway, hydrogen isn’t dangerous—or even toxic—unless it’s held within a confined space.”
Tor kept scanning while moving along the spongy path. But hydrogen readings never spiked enough to cause concern, let alone alarm. The smart-mob had wanted her to come up here for this purpose—to verify that onboard detectors hadn’t been tampered with by clever saboteurs. Now that her independent readings confirmed the company’s story, some people were already starting to lose interest. Ad hoc membership totals began to fall.
“Any leakage must be into the air,” continued the voice of the group mind, still authoritative. “We’ve put out a notice for amateur scientists, asking for volunteers to aim spectranalysis equipment along the Spirit’s route. They’ll measure parts-per-million, so we can get a handle on leakage rates. But it’s mathematically impossible for the amounts to be dangerous. Humidity may go up a percent or two in neighborhoods that lie directly below Spirit. That’s about it.”
Tor had reached the end of the walkway. Her hand pressed against the outer envelope—the quasiliving skin that enclosed everything, from gas cells and trusses to the passenger cabin below. Up close, it was nearly transparent, offering a breathtaking view outside.
“We passed the Beltway,” she murmured, a little surprised that the diligent guardians of Washington’s defensive grid allowed the Spirit to pass through that wall of sensors and rays without delay or scrutiny. Below and ahead, she could make out the great locomotive tug, Umberto Nobile, hauling hard at the tow cable, puffing along the Glebe Road Bypass. Fort Meyers stood to the left. The zeppelin’s shadow rippled over a vast garden of gravestones—Arlington National Cemetery.
“The powers-that-be have downgraded our rumor,” said the voice inside her ear. “The nation’s professional protectors are chasing down more plausible threats … none of which has been deemed likely enough to merit an alert. Malevolent zeps don’t even make it onto the Threat Chart.”
Tor clicked and flicked the attention-gaze of her specs, glancing through the journalist feeds at MediaCorp, which were now—belatedly—accessible to a reporter of her level. Seven minutes after the rise in tension caused by that spam of rumors, a consensus was already forming. The spam flood had not been intended to distract attention from a terror attack, concluded mass-wisdom. It was the attack. And not a very effective one, at that. National productivity had dropped by a brief diversion factor of one part in twenty-three thousand. Hardly enough damage to be worth risking prosecution or retaliation. But then, neohackers seldom cared about consequences.
&nb
sp; Speaking of consequences; they were already pouring in from her little snooping expedition. The mavens of propriety at MediaCorp, for example, must be catching up on recent events. A work-related memorandum flashed in Tor’s agenda box, revising tomorrow’s schedule for her first day of employment at the Washington Bureau. During lunch—right after basic orientation—she was now required to attend counseling on the Exercising Good Judgment in Impromptu Field Situations.
“Oh great,” she muttered, noticing also that the zeppelin company had applied a five hundred dollar fine against her account for Unjustified Entry into Restricted Areas.
PLEASE REMAIN WHERE YOU ARE, MS. POVLOV, said an override message. AN ATTENDANT WILL ARRIVE AT YOUR POSITION SHORTLY IN ORDER TO HELP YOU RETURN TO YOUR SEAT FOR LANDING.
“Double great.”
Ahead, beyond the curve of the dirigible’s skin, she spotted the massive, squat bulk of the Pentagon, bristling with missiles, lenses, and antennae … still a highly-protected enclave, even ten years after the Department of Defense moved its headquarters to “an undisclosed location in Minnesota.”
Soon, the mooring towers and docking ports of Reagan-Clinton National Skydrome would appear, signaling the end of her cross-continental voyage. Also finished—despite a string of interesting stories, from the Atkins Center to Hamish Brookeman railing at the Godmakers’ Conference—was all chance of a blemish-free start to her new career in Big Time Media.
She addressed the group mind. “I don’t suppose any of you have bright ideas?”
But it had already started to unravel. Membership numbers were falling fast, like rats deserting a sinking ship. Or—more accurately—monkeys. Moving on to the next shiny thing.
“Sorry, Tor. People are distracted. They’ve been dropping out to watch the reopening of the Artifact Conference. You may even glimpse some limos arriving at the Naval Research Center, just across the Potomac. Take a look as the Spirit starts turning for final approach…”
Blasted fickle amateurs! Tor had made good use of smart-mobs in the past. But this time was likely to prove an embarrassment. None of them would have to pay fines or face disapproval in a new job.
“Still, a few of us remain worried,” the voice continued. “That rumor had something … I can’t put my finger on it.”
The “voice” was starting to sound individualized and had even used the first person “I.” A sure sign of low numbers. And yet, Tor drew some strength from the support. Before an attendant arrived to escort her below, there was still time for a little last-minute tenacity.
“Can I assume we still have some zep aficionados in attendance?”
“Hardly anyone else, Tor. Some us are fanatics.”
“Good, then let’s apply fanatical expertise. Think about that leakage we discussed a while ago. We’ve been assuming that this zeppelin is making hydrogen to make up for a significant seep, into the air outside. That’d be pretty harmless, I agree. Have any of those amateur scientists studied the air near Spirit’s flight path, yet?”
A pause.
“Yes, several have reported in. They found no dangerous levels of hydrogen in the vicinity of the ship, or in its wake. The seep is probably dissipating so fast.…”
“Please clarify. No dangerous levels? Is it possible they found no sign of a hydrogen leak at all?”
The pause extended several seconds longer, this time. Suddenly the number of participants in the group stopped falling. In the corner of Tor’s specs, she saw membership levels start to rise again, slowly.
“Now that’s interesting,” throbbed the consensus voice in her ear.
“Several of those amateur scientists have joined us now.
“They report seeing no appreciable leakage. Zero extra hydrogen along the flight path. How did you know?”
“I didn’t. Call it a hunch.”
“But at the rate that Spirit has been replacing hydrogen…”
“There has to be some kind of leak. Right.” She finished that thought aloud. “Not into the baggage compartment or passageways, either. We’d have detected that. But the missing hydrogen must be going somewhere.”
Tor frowned. She could see a shadow moving beyond the grove of tall, cylindrical gas cells. A figure approaching. A crewman or attendant, coming to take her, firmly, gently, insistently, back to her seat. The shape wavered and warped as seen through the mostly transparent polymer tubes—slightly pinkish for hydrogen and then greenish tinted for helium.
Tor blinked. Suddenly feeling so dry mouthed that she could not speak aloud, only subvocalize.
“Okay … then … please ask the amscis to take some more spectral scans along the path of this zeppelin. Only this time … look for helium.”
The inner surface of her specs showed a flurry of indicators. Amateur scientific instruments, computer-controlled from private backyards or rooftop observatories, speckled the nation. Many could zoom quickly toward any patch of sky—hobbyists with access to better instrumentation than earlier generations of top experts could have imagined. Dotted lines appeared. Each showed the viewing angle of some home-taught astronomer, ecologist, or meteorologist, turning a hand- or kit-made instrument toward the majestic cigar shape of the Spirit of Chula Vista.…
… which had passed Arlington and Pentagon City, following its faithful tug into a final tracked loop, turning to approach the dedicated zeppelin port that served Washington, D.C.
“Yes, Tor. There is helium.
“Quite a lot of it, in fact.
“A plume that stretches at least a hundred klicks behind the Spirit. No one noticed before, because helium is inert and utterly safe, so no environmental monitors were tuned to look for it.”
The voice was grim. Much less individualized. With ad hoc membership levels suddenly skyrocketing, summaries and updates must be spewing at incredible pace.
“Your suspicion appears to be well based.
“Extrapolating the rate of helium loss backward in time, more than half of the Spirit of Chula Vista’s original supply of that gas may have been lost by now.…”
“… replaced in these green cells by another gas.” Tor completed the thought, while nodding. “I think we’ve found the missing hydrogen, people.”
For emphasis, she reached out toward one of the nearby green cells. The “safe” ones that were there to protect life and property, making disaster impossible.
It all made sense, now. Smart polymers were programmable—all the way down to the permeability of any patch of these gas-containing cells, the same technology that made seawater desalinization cheap and ended the Water Wars. But it was technology, and so could be used in a multitude of ways. If you were very clever, you might insert a timed instruction where two gas cells touched, commanding one cell to leak into another. Create a daisy chain. Vent helium into the sky. Transfer gas from hydrogen cells into neighboring helium cells to maintain pressure, so that no one noticed. Then trigger automatic systems to crack onboard water and “replace” that hydrogen, replenishing the main cells. Allow the company to assume a slow leak into the sky is responsible. Continue.
Continue until you have replaced the helium in enough of the green cells to turn the Spirit into a flying bomb.
“The process must be almost complete by now,” she murmured, peering ahead toward the great zep port, where dozens of mighty dirigibles could already be seen, some of them vastly larger than this passenger liner, bobbing gently at their moorings. Spindly fly-cranes went swooping back and forth as they plucked shipping containers from ocean freighters at the nearby Potomac Docks, gracefully transferring the air-gel crates to waiting cargo-zeppelins for the journey cross continent. A deceptively graceful, swaying dance that propelled the engines of commerce.
The passenger terminal—dwarfed by comparison to those giants—seemed to beckon with a promise of safety. But indicators showed that it still lay ten minutes away.
“We have issued a clamor, Tor,” assured the voice in her head. “Every channel. Every agency.”
A glance at spec-telltales showed Tor that, indeed, the group mind was doing its best. Shouting alarm toward every official protective service, from Defense to Homeworld Security. Individual members were lapel-grabbing friends and acquaintances, while smart-mob attendance levels climbed into five figures, and more. At this rate, surely the professionals would be taking heed. Any minute now.
“Too slow,” she said, watching the figures with a sinking heart. Each second that it took to get action from the Protector Caste, the perpetrators of this scheme would also grow aware that the jig is up. Their plan was discovered. And they would have a speedup option.
Speaking of the perps, Tor wondered aloud.
“What can they be hoping to accomplish?”
“We’re pondering that, Tor. Timing suggests that they aim to disrupt the Artifact Conference. Delegates arriving at the Naval Research Center are having a cocktail reception on the embankment right now, offering a fine view toward the zep port, across the river.
“Of course it is possible that the reffers plan to do more than just put on a show, while murdering three hundred passengers. We are checking to see if the Umberto tug has been meddled with. Perhaps the plan is to hop rails and collide with a large cargo-zep, before detonation. Such a fireball might rock the Capitol, and disrupt the port for months.
One problem with a smart-mob. The very same traits that multiplied intelligence could also make it seem dispassionate. Insensitive. Individual members surely felt anguish and concern over Tor’s plight. She might even access their messages, if she had time for commiseration.
But pragmatic help was preferable. She kept to the group mind level.
“One (anonymous) member (a whistle-blower?) has suggested a bizarre plan using a flying-crane at the zep port to grab the Spirit of Chula Vista when it passes near. The crane would then hurl the Spirit across the river, to explode right at the Naval Research Center! In theory, it might just be possible to incinerate—”
