For Stone that was a year out of his life wasted. But he’d spent the time preparing for his move to NASA, trying to be sure he started off his new career as well placed as he could be.

“Fifteen-second mark to separation. Chase planes on target. Ten seconds.”

He felt his heart, somewhere under the silver surface of his pressure suit, pumping a little harder. As it was supposed to at such moments.

“Three. Two. One. Sep.”

With a solid crack the B-52’s shackle released the X-15, and the plane dropped away from its mother, and Stone was jolted up out of his seat.

Stone emerged from the shadow of the bomber’s wing, at forty-five thousand feet, into a shock of brilliant sunshine. He was already so high that the morning light was electric blue, more like dusk. The chase planes were little points of silver light around him, with their contrails looping through the air.

The land curved below the plane’s nose, as if the Mojave was some huge, smooth dome. He could see the worn hump of Soledad, the Lonely Mountain, brooding over Rogers Dry Lake, half a mile above sea level. Everywhere the dried-up salt lakes glistened like glass, speckled with gray-green sagebrush and the twisted forms of Joshua trees. It was a flat, desolate, forbidding place. But every summer the desert sun baked the damp lake beds to a flat and smooth surface. The whole place was like one huge runway, and you could land anywhere in reasonable safety.

It was a little after ten-thirty in the morning.

Stone pushed the button to ignite the X-15’s rocket engine.

He was kicked in the back, hard. The plane’s nose was tipped up into the sky as ammonia and oxygen burned behind him, and he rode higher into the deepening blue. He could hear his own breathing inside his helmet; otherwise, there was barely a sound — he was outpacing the noise and exhaust plumes behind him.

Far ahead he saw a speck of light, like a low star. It was a high chase plane. It grew out of nowhere in a flash, and plummeted backwards past Stone, as if it were standing still.

At forty thousand feet he reached .9 Mach, and he could feel a bumping, like a light airplane flying in turbulence. He was moving so quickly that the air molecules couldn’t get out of the way of his craft in time.

The turbulence smoothed out as he went supersonic.

Eighty thousand feet.