“I suspect that before his flight, Icarus was throwing up. I wish we could just go into the mountains again, Joe, go riding again like we used to. I’ve ridden that horse of mine just once this year. I know they don’t need me in there, but it’s my test.” He looked up at Joe. The rest of Oppy had been worn down to bones and clothes while the blue eyes had the intensity of a man enduring pain. “I asked Groves for another week or just another four days. When this is over, we’ll go riding.”

“Sure.”

Harvey called Joe inside. The core was closed and complete and sat in a lead-lined wooden box.

“He’s been like this ever since he got here. Maybe he should go back to the Hill.”

“It’s his test,” Joe said.

They carried the box on a litter out to Harvey’s car and put it on the backseat. Joe took Oppy in the jeep and led the way back to the tower. The breeze of late afternoon was picking up; dust devils whipped around the tower base.

Within the tent, Foote and Jaworski had removed the polar cap at the top of the bomb and taken out a brass plug so that the plutonium core could be inserted. Harvey opened his box and attached the core to a vacuum cup. Nobody wanted to damage the precious core with screws or bolts, and being scientists they trusted the reliability of a vacuum. Harvey tested the cup’s seal, then hooked the chain of a manual hoist onto the cup’s eyes. He pulled off his lab coat and kicked it away, then tested the seal again. Harvey looked like a plump and innocent boy, the sweat coursing off his belly, his fine blond hair standing as if magnetized. Foote cranked the core up from its box. From a corner of the tent, Oppy and Joe watched Jaworski steady the core with a pencil as Foote swung it over the waiting bomb.

Wind beat on the canvas. “One proper dust devil and a few grains of sand and we can put our symmetrical implosion into a pisspot,” Foote said.

He lowered the core. One moment it hovered over the bomb like a moon above a larger body; the next it was descending by its chain into the bomb’s interior.

And stuck.

Jaworski waved his hand up. His mustache had started to sag. Foote cranked up the core and lowered it into the bomb again. It stuck.

Foote cranked the core halfway out of the bomb, slipped the hoist’s ratchet and painstakingly let out the chain again. The core made its slow downward passage, nudging lenses of high explosive as it dropped.

And stuck. By a millimeter or so, the plutonium core was simply too big or the hollow inside the bomb was too small.