Machine or not, she sensed panic.

They arrived at a small, compact briefing room. A single table stretched the length of the room; it was oak, its surface polished smooth, a bizarre touch of luxury in this dehumanized cavern.

She had arrived in the middle of a briefing. It was a chaotic hubbub.

Al Hartle sat at the far end of the table. Gareth Deeke sat alongside him, his eyes hidden by his mirrored glasses. There were several others here, mostly men, mostly heavy-set and middle-aged. Some wore service uniforms, mostly from the U.S. armed forces, but there were also representatives from the military establishments of Canada, Quebec, New Columbia, Idaho. There were even a couple of Russian officers: evidently the embodiment of some post-Cold War strategic tie-up between the U.S. and post-Soviet Russia, a new cooperative understanding as the former adversaries banded together in the face of a newly hostile and baffling world.

Anyhow it was quite an assembly, a representation of the military establishments of two continents.

Around the walls of the room, framing the group at the table, a series of young officers sat at compact workstations, the glow of their softscreens illuminating their earnest, smooth faces. She could see information flowing in continually over the surface of the soft-screens, and occasionally scribbled notes were passed to the heavyweights at the main table. Network cables lay across the floor, roughly anchored here and there with duct tape. Jackets had been draped over the backs of chairs, ties were roughly loosened, and a pall of blue-grey smoke hung over the center of the room.

There was a stench of stale sweat, of too much aftershave. Of fear.

Oddly, she found she welcomed the body stink. At least, she thought, you could tell there were living human beings in this place of metal and plastic.

Fahy was waved to a seat.

Hartle clapped his hands, and the hubbub died a little. “Let’s try and get some kind of overview here,” he said. “Gareth. What’s the most significant item we have, in your view, right now?”

Deeke didn’t hesitate. “As far as the President is concerned, it must be the Wall Street bomb. The physical damage wasn’t important, Al. In fact it was just a suitcase bomb. The point of it was the electromagnetic pulse it delivered. Al, it knocked out everything: bank transfer networks, stock and bond markets, commodity trading systems, credit card networks, telephone and data transmission lines, Quotron machines… We’re looking at financial chaos, a meltdown of the global finance system. All from one suitcase bomb.

“General, we have two hundred million computers tying us together through an array of land and satellite-based communication systems. We thought we were protected. We weren’t. The nodes of our government and commercial computer systems are so poorly shielded that it’s been a chicken run for the enemy, or their agents. And in our systems themselves, even the most secure, we have evidence of the work of crackers — malevolent hackers — and cruise viruses, targeted at our vulnerable points. Al, at this moment I don’t think we can trust any of the information we do have coming in here, or even our weapons targeting and arming systems.”

“All right,” Hartle snapped. “What else?”

“We’ve lost our satellites,” another officer said bluntly.

“How? Anti-satellite strikes?”

“ASATs aren’t necessary,” Deeke said. “It’s easier and cheaper to soft-kill a satellite: damage, distort, even reprogram the information it processes and transmits. You can jam, intercept, spoof, hit the ground stations, break into the comms networks… Al, this is knowledge warfare. We have to assume that there are troop movements, going on right now. Launches of their CSS-2 IRBMs. Stuff we can’t see any more—”

“Knowledge warfare, horseshit. I’ll tell you what this is,” Hartle said. This is an electronic Pearl Harbor. The Red Chinese have blinded us. They’re doing to us what we did to them over Taiwan, back in ’12. We just didn’t think big enough, is all; we never thought they would attempt this—”

“And of course we have a rather larger problem,” Deeke said mildly.

Hartle turned to Fahy.

“Miss Fahy,” he said, glowering at her. “Welcome to hell. Now, tell us about 2002OA.”

Fahy, nervous, rumbling, stood up and walked to the head of the table, opposite Hartle. “2002OA is a NEO. A near-Earth object, an asteroid. We have four dedicated NEO search programs. Three in the northern hemisphere, one in the south. The U.S. has been running planet-crossing asteroid surveys for four decades now out of Mount Palomar, Kitt Peak and the Lowell Observatory. The surveys use photographic methods, with some upgrade to electronic methods. Palomar alone is responsible for the discovery of one-third of the NEO population known today. All these observatories are situated in the south-west of north America, and so cannot reach southern declinations. In response, a program called the Anglo-Australian Near-Earth Asteroid Survey was initiated in the 19908…”

“So,” Hartle snapped, “where the fuck is 2002OA?”

She fumbled with her softscreen, working through the presentation she had prepared, at last bringing up the image she wanted: a pencil of possible orbits, fanning out from 2002OA’s present position. The orbits enveloped the Earth.

“The orbital elements of 2002OA are not precisely determined, yet. For one thing it is only visible from one NEO tracking station, the one in Australia, though we’re trying to bring more resources to bear. It’s possible, but not certain, that 2002OA will collide with Earth. We certainly can’t be specific about where, precisely, in geographic terms. The orbital data is too fragmentary at present to be able to—”

Hartle closed his eyes. “Which hemisphere?”

“I can’t tell you that, sir.”

Deeke said, “NORAD and NASA are refining their projections all the time, Al.”

Hartle said, “But if we can’t even figure out where it is heading, how was it possible for the fucking Chinese to aim it?”

Deeke shrugged. “By placing a spacecraft on the spot. By doing navigation from there, they could achieve much greater precision. Maybe they even sent up a man to do it, General. After all, they aren’t scrupulous about spending human lives.”

“And what damage is this fucker going to do to us?”

“General, we think the Chinese miscalculated,” Fahy said, flicking through the projections her staff had prepared. “2002OA is a big rock. Bigger than they need, if they just wanted to strike at the U.S. We think they intended some kind of glancing blow, or maybe to calve off a piece of the rock. Then we’d face localized destruction, maybe something like a nuclear winter. A Tunguska rock on New York. A Meteor Crater where Washington is. We think that was the plan. But 2002OA is too large. Instead, we may be looking at some kind of Cretaceous-Tertiary boundary impact—”

Hartle turned to Deeke. “What the fuck?”

“A dinosaur killer, General,” Deeke said softly.

There was a moment of silence.

Hartle said to Fahy, “So tell me how we shoot down this motherfucker.”

She rumbled through her notes. “In general, the strategy for dealing with incoming objects requires spacecraft capable of rendezvousing with a threatening NEO and deflecting it by incrementing its velocity with a delta-vee — that is, an impulse — sufficient to cause them to miss the Earth. There are two generic strategies: remote interdiction, when the collision is predicted several orbital periods away, and terminal interception — when the collision is imminent, with the projectile less than one astronomical unit away — that is, days away from impact — and closing. Remote interdiction requires relatively small delta-vees, terminal interception much larger. In both cases, a deflection velocity is applied sufficient to cause it to drift from its original trajectory by at least one Earth radius. In cases of terminal interception it is best to apply the impulse perpendicularly to the projectile’s motion, which imparts an eccentricity to its orbit. The deflection delta-vee required is inversely proportional to the distance from Earth. And because of this—”