He’d never seen a systems signature like this before, not in any of the sims he’d gone through. But then, even after twelve years of flights, Apollo-Saturn was still an experimental system. You’d test-fly an airplane far more times than any spacecraft had ever flown, before declaring it operational.

So what was hitting him? It could be instrumentation problems, flaky readouts, as EECOM seemed to suspect. Or it could be that the Service Module had blown out, knocking the whole stack sideways. Or something else might have blown, and damaged the Service Module.

INCO’s timing came in. His antenna problems dated from a few seconds after they’d lit the NERVA.

For the first time in several seconds Donnelly glanced at the trajectory plot board. The spacecraft was diverging, markedly, from the path it should have followed, had the NERVA been burning smoothly.

The S-NB looked to have shut down.

“Guidance, you want to confirm that deviation?”

“Rog, Flight.” Guidance was the ground navigator. Guidance must be looking at multiple problems, too, as the spacecraft drifted from its trajectory and tumbled away from its intended attitude.

“Booster, you have anything to report?”

Mike Conlig did not reply. Donnelly could see how he was hunched over his console. “Booster?”

York said, “The crew is reporting a smell of ozone, inside their helmets.”

“Flight, this is Surgeon. I have a contrary indication.” The flight doctor on this flight was a crop-headed Oklahoman sitting in the row in front of Donnelly, with the systems guys, at the left-hand end next to Natalie York. He was wearing a button badge which read FUCK IRAN. His voice was taut, urgent.

Donnelly switched him onto a closed loop. “Go, Surgeon.”

“Flight, I’m monitoring a surge of radiation flux through the spacecraft cabin. And some changes in the crew’s vital readings.”

Donnelly was thinking through York’s brief report. They can smell ozone. Oxygen, ionized by radiation. Radiation from the NERVA. Jesus Christ almighty.

It was real, then. Not just flaky instrumentation. And the Russians orbited a goddamn Vietnamese in Salyut this year. The press will crucify us.

Because of the two simultaneous missions in progress Bert Seger had been away from the office for three days, and he was taking a chance to work through his mail. He’d only been at it for a few minutes when he got a call on the squawk box, the line that linked up the senior staff in Building 2.

There had been some kind of problem with the Apollo-N flight, and Seger had better get on over to the MOCR.

Angrily, Seger folded up his mail. With the NERVA, it was one damn thing after another.

The voltage needle on Bus A sank past the bottom of its scale. More warning lights came on.