And the noise of the jets rose to a roar, drowning out his words.

The plane started to taxi.

Stone, sitting in his bubble ahead of her, looked out calmly, his motions deft and precise. The controls before her moved in sympathy with Stone’s, working themselves like a high-tech pianola.

She felt her pulse rate rising, her breathing deepening, and the rubber stink of her oxygen mask grew sharper; she felt sweat pool under her goggles, on her squeezed-up cheeks.

She consoled herself that she was going on a ride which few people would experience: high, fast, probably extraordinarily beautiful. Even if she left the corps tomorrow, she would have that to take away from there.

Yes, but I’m pretty sure I could get by without it…

Without warning, the plane threw itself down the runway, pressing her back into her seat. Within a few seconds she could feel the wheels leaving the ground.

The plane pitched upward steeply, and she lost sight of the ground.

There was a layer of cloud above, lumpy cumulus. The clouds seemed to explode at her, and she shot into white mist. She was through it in a second, emerging into bright, clear sunshine.

She glanced down: the land was already lost, remote, a patchwork of faded brown with the gray shadows of clouds scattered over it.

The T-38 rose almost vertically, like a rocket. In a few seconds, the sky faded down to a deep purple.

The surface of Earth was remote, small, the works of humanity already reduced to two-dimensional splashes of color. It astonished her to think, given the facility with which she had leapt from the ground, that just a century ago no human on the planet had undergone such an experience.

Scientist-astronauts no longer had to slog through the hell of flight school. But they still needed to go through dynamic situations: to gain experience of microgravity and acceleration, to recognize the symptoms of airsickness and hypoxia. So, the price the scientist-astronauts had to pay was regular hours of flying backseat in a Northrop T-38, the most advanced jet trainer.

Experienced astronauts were encouraged to take up the rookie scientists. And once you were up there, they could do whatever the hell they liked with you.

But she trusted Stone. She appreciated the fact that he was taking time out of his own Moonlab/Soyuz training for this piece of nursemaiding.

“How about that,” Stone said. “Forty-eight thousand feet. Higher than you’ve ever flown before, Natalie.”

So high she was already in the stratosphere, higher than the tallest mountain, so high she couldn’t breathe unaided. The edge of space, right? Welcome to your new home, spacegirl.

“Okay,” Stone said. “Let’s start gently. We’ll slow her down. Can you read the airspeed?”

“Sure.”

“Follow what I do.”

When the jet got to under two hundred miles an hour, it bucked and juddered, as if the air had become a medium of invisible lumps.