Into Sax’s mind, as he considered the great object flying over them, came the image of a magnifying glass, held over dry weeds and an aspen branch. Smoke, flame, fire. The concentrated rays of the sun. Photon assault. “Aren’t we close enough yet? It looks like it’s right over us.”

“No, we’re well out from under the edge. It wouldn’t do to get under that thing, although I suppose the focus wouldn’t be right to fry us. Anyway it’s moving over the burn zone at almost a thousand kilometers an hour.”

“Like jets when I was young.”

“Uh.” Green lights blinked on one of his consoles. “Okay, here we go.”

He pulled back on the stick and the plane stood on its tail, rising straight at the lens, which was still another hundred kilometers higher than they were, and well to the west of them. Peter pushed a button on the console. The whole plane jerked as a bank of fletched missiles appeared from under the plane’s stubby wings, lofting with them and then igniting like magnesium flares and shooting up and away, toward the lens. Pinpricks of yellow fire against that huge silvery UFO, eventually disappearing from sight. Sax waited, lips pursed, and tried to stop his blinking.

The front edge of the lens began to unravel. It was a flimsy thing, nothing but a great spinning cup of solar sail bands, and it came apart with startling rapidity, its front edge rolling under it until it was tumbling forward and down, trailing long looping streamers which looked like the tangled tails of several broken kites, all falling together. A billion and a half kilograms of solar sail material, in fact, all unraveling as it fluttered down in its long trajectory, looking slow because it was so big, though probably the great mass of material was still moving at well above terminal velocity. A good portion of it would burn up before it hit the surface. Silica rain.

Peter turned and followed it in its descent, keeping well to the east of it. And so they could still see it below them, there in the violet morning sky, as the main mass of it heated to an incandescent glare and caught fire, like a great yellow comet with a hairy tangled silver tail, dropping down to the tawny planet. All fall down.

“Good shot,” Sax said.

• • •

Back in Wallace Crater they were welcomed as heroes. Peter deflected all congratulations: “It was Sax’s idea, the flight itself was no big deal, just another reconnaissance except for the firing, I don’t know why we didn’t think of it before.”

“They’ll just drop another one into position,” Ann said from the edge of the crowd, staring at Sax with a very curious expression.

“But they’re so vulnerable,” Peter said.

“Surface-to-space missiles,” Sax said, feeling nervous. “Can you invent— can you inventory all orbiting objects?”