Guidance came on line. “The bird’s attitude is still changing. They’ve got to stop it. We’re heading for gimbal lock.”

“I hear you, Guidance.”

Gimbal lock meant the spacecraft was tumbling beyond the tolerance of the inertial guidance system. The platform could be reset by eye again. But if Donnelly was forced to go for an emergency reentry, he needed alignment control immediately.

Somehow, though, he felt that alignment loss, even a gimbal lock, was the least of the spacecraft’s problems just then.

“Houston, Apollo-N.” It was Jim Dana; to Natalie York, Jim’s voice sounded thin, frail, but controlled. “We’re seeing some kind of gas, venting from the stack.”

York’s skin prickled with a sudden chill.

“Rog, Apollo-N,” she said. “Can you tell if it’s coming from the S-NB tank, or the Service Module?”

“We can’t tell. Both, possibly.”

She’d been following the controllers’ terse dialogue. The controllers were still working to the assumption that there was some kind of instrumentation or telemetry problem to explain the multiple anomalies.

But if the ship was venting gas, that couldn’t be it. The problem couldn’t be just instrumentation or an electrical screwup. And besides, she could see that Surgeon, next to her, had switched onto a closed loop.

Something, some violent and destructive event, had happened to Apollo-N, up there in low Earth orbit, to a spacecraft with a nuclear pile attached to its tail.

She glanced across at Mike. He was still hunched over his console and whispering into his headset. Why doesn’t he say something to Flight?

She became aware that her right hand was clutching the thin metal maintenance handle of her console; her hand was closed into a fist, painfully.

Her throat was dry, and she had to force herself to swallow before she could speak again.

Ben’s up there. What in hell is going on?

Gregory Dana, in the Viewing Room, could see the spacecraft icon drifting from its programmed trajectory on the big plot board, and he could follow enough of the controllers’ terse exchanges to figure out that something catastrophic had happened to Jim’s ship.

The Viewing Room was steadily filling up — as was the MOCR amphitheater itself — as off-duty personnel came hurrying in, responding to the deepening atmosphere of crisis.

Dana was joined at the window by one of the astronaut corps, Ralph Gershon, whom Dana had met a couple of times through Jim.

Gershon stared out at the frantic huddles in the MOCR and snorted contempt. “Jesus. Look at them huddling up. They always go through the same thing. What happened? Where are we? What are we going to do about it? They’re so damned slow, and restricted in the way they think. And meanwhile the bird drifts around the sky, broken-winged.”

Broken-winged.

The problems must be with the nuclear engine. Everything, every anomaly, had flowed from that moment.