Нил Стивенсон - Termination Shock

“As long as the FAA has been so good as to clear the airspace,” he said, “we’re gonna launch some more stuff. Might want to plug your ears.” He set the microphone down, turned his back on the crowd, and faced the complex at the other end of the valley. The crowd grew silent. An alarm klaxon could be heard in the distance. T.R. stepped carefully over the caution tape, strolled out into the open near the rocket launchers, and checked his watch.

A spark of light gleamed from the top of the head frame, then winked out. A few seconds later the valley was walloped by a sonic boom. T.R. was looking almost vertically up into the sky, but there was nothing to see. He checked his watch again, then turned back and indicated the microphone. An ELog employee snatched it from the table and ran it over to him. “Next one’s in seven minutes,” he said. “You’ll want to come out into the open if you are hoping to see anything.”

People slowly, then suddenly evacuated the bleachers and came toward T.R., stepping out of the canopies’ shade and into direct sunlight. The caution tape was severed and allowed to flutter in the breeze.

“The muzzle flash’ll catch your eye,” T.R. said. “But if you look at that, you’ll miss it. Shell’s already long gone. You got to look into the space above. Next one’s in 3 . . . 2 . . . 1 . . .”

Saskia just glimpsed it, moving straight up at fantastic velocity, as the muzzle flared and extinguished below.

A third barrel fired seven and a half minutes later, and this time she was able to track it for a few seconds before it became too small for the naked eye to see. Each launch was followed by another sonic boom equal to the first.

“Holy shit,” said the Right Honorable the Lord Mayor.

“I know,” said Daia Chand, next to him. “Even after all this, I didn’t actually believe he was going to pull the trigger.”

“It’s happening,” Alastair said. “After all this—it’s actually happening. I sort of can’t believe it. We are fixing the climate.”

“ Changing it, anyway,” Eshma returned.

“This’ll bring the temperature down?” Rufus asked.

“If he can keep firing that gun,” Saskia said.

“Sounds like fixing to me,” Rufus concluded.

Not far away, the three Venetians were engaging in a round robin of embracing and kissing. Sylvester was standing with his arms folded, looking dumbfounded. After the third sonic boom, he walked up to T.R. and shook his hand, grinning broadly under the brim of his borrowed cowboy hat.

The Biggest Gun in the World fired each of its barrels three times, launching a total of eighteen shells, before it fell silent. The test lasted for a couple of hours, not counting shell recovery time. Well before the end of it, Saskia had begun to feel dizzy from the heat. She and many others retreated to the air-conditioned comfort of the train cars to watch the proceedings on video screens.

“So this is what it looks like with an N of eighteen,” Alastair mused over a bottle of Corona. Saskia had spent enough time with him to recognize this as statistician-speak. Launching a single shell—an N of 1—would have taught T.R. a lot. Launching two would have taught him a little more. An N of eighteen was big enough to do some statistical analysis and get a picture of the range of outcomes.

The positions of the eighteen shells were plotted and updated on a real-time map displayed on a big monitor. They were spread out like beads on a string along a trajectory that rose straight up from the Flying S Ranch and then spiraled down through Mexican airspace. They all seemed to be following the same basic flight plan, like cars in an aerial train. Each had two video cameras, one aimed forward and the other aimed back. The twin feeds from one shell were up on the video screens. They couldn’t have been more different. The view forward was of a black sky above a curved horizon limned in blue. The view back was an endless series of flashes, which became so visually annoying that the pane had to be minimized. But it confirmed that the sulfur-burning pulse jet had ignited and was farting away.

At one end of the car T.R. was doing an interview with a tame journalist. With a couple of beers in him, he had become amusingly and colorfully exasperated by this person’s stubborn misunderstanding of the muzzle flash. “It is just a by-product . We would eliminate it if we could. If we used helium, it wouldn’t happen at all—and it wouldn’t matter because the purpose of that gas is just to be like the air in a peashooter. Unavoidably, some of it leaks out of the muzzle after the shell has departed. We control that as much as we can with check valves and such. But it’s safer to burn it off than to just have it drifting around god knows where.” He caught the eye of an aide who seemed to specialize in media communications. “We need more animations or something to better illustrate that—it is just gonna be a chronic misunderstanding.”

Another invited journalist asked a question that Saskia couldn’t quite hear. T.R. nodded. “The gun just lobs the shell up to the altitude we want—the stratosphere. About eighty thousand feet. Where sulfur does no harm—and much good. Now, at that point it’s just gonna fall straight back down unless we do something. We could just detonate it with an explosive charge and it would disperse the sulfur. Hopefully some of it would burn. That was actually plan A. But our aerospace engineers didn’t think that was fancy enough and so they ginned up the idea for a sulfur-burning engine that can keep the shell airborne for a little while. It’s got the worst performance characteristics you can imagine but we don’t care —it gives us a few minutes for the shell to remain at altitude and disperse the SO 2more widely where the jet stream can catch it and begin spreading it around. Then the shell runs out of fuel and glides to the ground and we try to catch it.”

T.R. drew the journalists’ attention to a feed from another camera, this one near the ground, aimed at a stretch of ranch property covered by nets stretched between poles. “This here is all there is to it,” T.R. said. “Same as you see at the circus. It’s a few miles from here, down toward the Rio Grande.”

There followed a few minutes’ futzing around with video feeds and camera angles that only gave a helter-skelter picture of what was going on. “The point,” T.R. eventually said, after his frustration had reached a crescendo and then collapsed in a farrago of basically humorous cursing and hat-throwing, “is that we are recycling the goddamn shells. We catch them in the net and toss them in the back of a truck and drive them back to the reloading facility. Providing jobs, good safe jobs, on the ground. Come out here if you want to see what I mean.”

Saskia and others followed as T.R. led the reporter out of the Beer Car and across a few meters of open ground to a flat area where another one of those ubiquitous pop-up sun canopies had been pitched. Beneath it, a giant bullet rested on a display stand. T.R. shooed a white hat out of the way in mid demo. “Most of the shell is hollow. Empty space. It’s a container for sulfur,” he said. “That being the entire point.” He patted its base, which was flat. “This here is just a sabot for the hydrogen to push against while it’s in the gun barrel. It falls off immediately and we retrieve it.” He yanked the sabot off and chucked it on the ground. Revealed was a conical hole penetrating into the middle of the shell. “The nozzle bell where combusted sulfur dioxide shoots out of the combustion chamber.” He walked around to the pointed nose of the bullet, and simply yanked it off. “Another disposable part. Falls off in the stratosphere, comes down like a badminton birdie. We find it and reuse it. Or not.” Revealed under the nose cone was another tapering hole, like the intake of a jet engine. “Where the air comes in.” He stepped back. By the removal of the sabot and the nose cone, the bullet had been transformed into a jet engine. “Now it can generate thrust by exhausting sulfur dioxide, which has the interesting side effect of saving millions of lives and trillions of dollars from the effects of global climate change. But from a strictly aerospace engineering point of view we have a problem, which is that it can’t generate nearly enough thrust to stay aloft for long.” He opened a hatch on the top of the shell to reveal a shallow but broad compartment just underneath, wrapping partway around the upper part of the shell’s cylindrical body. It was full of orange fabric. “This is too unwieldy to display here, so here’s a picture of what it looks like when it’s deployed.” He gestured toward a poster, mounted on a slab of foam core zip-tied to the canopy’s frame. It depicted one of those parasailing wings often seen towed behind speedboats in seaside resorts: a curved leading edge, a wing of taut fabric behind it, and a system of shroud lines converging on, and supporting, the payload. “This object deploys and gives it some appreciable L over D,” T.R. said, “which means it can stay aloft for a little while through a combination of running the engine and shedding altitude. The more sulfur it burns, the lighter it becomes. The farther it descends, the thicker the air. Both work in our favor. By the time the tank is empty, this thing is pretty damned airworthy and it can glide for a long ways. Even if it’s out over Mexico somewhere it can glide back and try to hit one of those nets.”