"Can't stand them."
"Well, it's better than walking." He pointed off to one side, where an iron ladder ran up the wall to the ceiling. "When the elevator goes out, we have to climb up that." I shuddered. "Not me."
We rode the elevator all the way up to the ceiling, three stories above the ground. Hanging beneath the ceiling was a tangle of ducts and conduits, and a network of mesh walkways to enable workers to service them. I hated the mesh, because I could see through it to the floor far below. I tried not to look down. We had to duck repeatedly beneath the low-hanging pipes. Ricky shouted over the roar of the equipment.
"Everything's up here!" he yelled, pointing in various directions. "Air handlers over there! Water tank for the fire sprinkler system there! Electrical junction boxes there! This is really the center of everything!" Ricky continued down the walkway, finally stopping beside a big air vent, about three feet in diameter, that went into the outer wall.
"This is vent three," he said, leaning close to my ear. "It's one of four main vents that exhausts air to the outside. Now, you see those slots along the vent, and the square boxes that sit in the slots? Those are filter packs. We have microfilters arranged in successive layers, to prevent any external contamination from the facility."
"I see them…"
"You see them now," Ricky said. "Unfortunately, the contractor forgot to install the filters in this particular vent. In fact, they didn't even cut the slots, so the building inspectors never realized anything was missing. They signed off on the building; we started working here. And we vented unfiltered air to the outside environment."
"For how long?"
Ricky bit his lip. "Three weeks."
"And you were at full production?"
He nodded. "We figure we vented approximately twenty-five kilos of contaminants."
"And what were the contaminants?"
"A little of everything. We're not sure of exactly what."
"So you vented E. coli, assemblers, finished molecules, everything?"
"Correct. But we don't know what proportions."
"Do the proportions matter?"
"They might. Yes."
Ricky was increasingly edgy as he told me all this, biting his lip, scratching his head, avoiding my eyes. I didn't get it. In the annals of industrial pollution, fifty pounds of contamination was trivial. Fifty pounds of material would fit comfortably in a gym bag. Unless it was highly toxic or radioactive-and it wasn't-such a small quantity simply didn't matter. I said, "Ricky, so what? Those particles were scattered by the wind across hundreds of miles of desert. They'll decay from sunlight and cosmic radiation. They'll break up, decompose. In a few hours or days, they're gone. Right?"
Ricky shrugged. "Actually, Jack, that's not what-"
It was at that moment that the alarm went off.
It was a quiet alarm, just a soft, insistent pinging, but it made Ricky jump. He ran down the walkway, feet clanging on the metal, toward a computer workstation mounted on the wall. There was a status window in the corner of the monitor. It was flashing red: PV-90 ENTRY.
I said, "What does that mean?"
"Something set off the perimeter alarms." He unclipped his radio and said, "Vince, lock us down."
The radio crackled. "We're locked down, Ricky."
"Raise positive pressure."
"It's up five pounds above baseline. You want more?"
"No. Leave it there. Do we have visualization?"
"Not yet."
"Shit." Ricky stuck the radio back on his belt, began typing quickly. The workstation screen divided into a half-dozen small images from security cameras mounted all around the facility. Some showed the surrounding desert from high views, looking down from rooftops. Others were ground views. The cameras panned slowly.
I saw nothing. Just desert scrub and occasional clumps of cactus.
"False alarm?" I said.
Ricky shook his head. "I wish."
I said, "I don't see anything."
"It'll take a minute to find it."
"Find what?"
"That."
He pointed to the monitor, and bit his lip.
I saw what appeared to be a small, swirling cloud of dark particles. It looked like a dust devil, one of those tiny tornado-like clusters that moved over the ground, spun by convection currents rising from the hot desert floor. Except that this cloud was black, and it had some definition-it seemed to be pinched in the middle, making it look a bit like an old-fashioned Coke bottle. But it didn't hold that shape consistently. The appearance kept shifting, transforming. "Ricky," I said. "What are we looking at?"
"I was hoping you'd tell me."
"It looks like an agent swarm. Is that your camera swarm?"
"No. It's something else."
"How do you know?"
"Because we can't control it. It doesn't respond to our radio signals."
"You've tried?"
"Yes. We've tried to make contact with it for almost two weeks," he said. "It's generating an electrical field that we can measure, but for some reason we can't interact with it."
"So you have a runaway swarm."
"Yes."
"Acting autonomously."
"Yes."
"And this has been going on for…"
"Days. About ten days."
"Ten days?" I frowned. "How is that possible, Ricky? The swarm's a collection of micro-robotic machines. Why haven't they decayed, or run out of power? And why exactly can't you control them? Because if they have the ability to swarm, then there's some electrically mediated interaction among them. So you should be able to take control of the swarm-or at least disrupt it."
"All true," Ricky said. "Except we can't. And we've tried everything we can think of." He was focused on the screen, watching intently. "That cloud is independent of us. Period."
"And so you brought me out here…"
"To help us get the fucking thing back," Ricky said.
DAY 6
9:32 A.M.
It was, I thought, a problem no one had ever imagined before. In all the years that I had been programming agents, the focus had been on getting them to interact in a way that produced useful results. It never occurred to us that there might be a larger control issue, or a question of independence. Because it simply couldn't happen. Individual agents were too small to be self-powered; they had to get their energy from some external source, such as a supplied electrical or microwave field. All you had to do was turn off the field, and the agents died. The swarm was no more difficult to control than a household appliance, like a kitchen blender. Flip the power off and it went dead.
But Ricky was telling me this cloud had been self-sustaining for days. That just didn't make sense. "Where is it getting power?"
He sighed. "We built the units with a small piezo wafer to generate current from photons. It's only supplementary-we added it as an afterthought-but they seem to be managing with it alone."
"So the units are solar-powered," I said.
"Right."
"Whose idea was that?"
"The Pentagon asked for it."
"And you built in capacitance?"
"Yeah. They can store charge for three hours."
"Okay, fine," I said. Now we were getting somewhere. "So they have enough power for three hours. What happens at night?"
"At night, they presumably lose power after three hours of darkness."
"And then the cloud falls apart?"
"Yes."
"And the individual units drop to the ground?"
"Presumably, yes."
"Can't you take control of them then?"
"We could," Ricky said, "if we could find them. We go out every night, looking. But we can never find them."
"You've built in markers?"
"Yes, sure. Every single unit has a fluorescing module in the shell. They show up blue-green under UV light."
"So you go out at night looking for a patch of desert that glows blue-green."
"Right. And so far, we haven't found it."