Two more such rockets, each a little bigger than the last, were launched in short order by other children. "And the range is open!" Lou then announced. This was apparently the signal for the kids to run out there and find their rockets among the cacti and the rattlesnakes. While they did so, Lou delivered the promised peroration on federal airspace regulatory policy. "Those rockets y’all just saw can’t go higher than fifteen hundred feet," he said. "The engines is just too small, they ain’t got the impulse. Impulse is a little old scalar variable defined as the product of—" He noticed T.R. making a throat-cutting gesture and broke off before he could supply the mathematical formula. "Point is, the FAA don’t care ’cause we ain’t messing with their airspace! But these two big boys still on the pads here," he said, waving at the remaining rockets, "that is a different story! These have . . ." He trailed off, performing a mental calculation. "Sixteen thousand, three hundred and eight-four times the impulse of Jo Anne’s little old Estes Alpha! They can go high!" He pronounced it "hah." "So hah they could maybe hit a plane, or vice versa. So every month when we hold a meeting of the Flying S Ranch Employees Model Rocketry Club, you know what we gotta do?" It was probably meant as a rhetorical question but still elicited a smattering of "No! What?" from the bleachers. This knocked Lou off his stride but he soldiered on. "We gotta get us a permit from Uncle Sam! It ain’t that hard. They’re real nice about it. We fill out a little old form says we are fixing to launch a couple of high-power model rockets from the Flying S Ranch on such-and-such a day at such-and-such a time and you better spread the word to all the pilots not to fly over the area! And that’s exactly what they do! Just like that, the FAA sends out a Notice to Airmen and warns all the pilots to steer clear of the area and keep that box of airspace—you can think of it as a box—empty. Now, some of these cowboys round here have pilot licenses. I guess there’s Meskin drug runners too, but we don’t care if we hit them. Anyhow, they don’t bother reading the Notice and come flying around anyway, so we go belt-and-suspenders on it. We got watchers posted all round, watching the sky to warn us of any of them interlopers. If they tell us the sky’s clear, which it usually is, we’re good to go!" This seemed an obvious applause line, so the crowd made scattered "Woo!" noises while Lou conferred with a younger club member who was wearing a headset and tending to a radio—or, at any rate, a mess of cabled-together laptops and mystery boxes that seemed to answer to the same purpose as a radio. This culminated in a lot of serious nodding. "Skies are clear! Visibility is excellent! Sheng’s gonna launch a high-power rocket, take some pictures of us from ten thousand feet. Say cheese! Take it away, Sheng!"