Dana checked the Service Module’s fuel cell 1, which was supposed to feed Bus A. It was dead. His gloved fingers clumsy with the switches, Dana began to reconnect the Command Module’s systems from Bus A onto Bus B.

Another red light came on. Bus B was losing voltage as well. He checked fuel cell 3, the feed for Bus B; it was dead, too.

Jesus. We’ve lost the Service Module. It’s Apollo 13 over again.

He made his report, trying to keep his voice level. Mary would be listening, probably the kids. “Okay, Houston, I tried to reset, and fuel cells 1 and 3 are both showing gray flags. I’ve gotten zip on the flows.”

“Acknowledged, Apollo-N. EECOM has copied.”

Earth, beautiful, unperturbed, drifted past the windows.

The spacecraft and booster had been set rotating by that mysterious bang. Dana knew the ship’s attitude control systems should have been trying to steady their slow tumble, but there was no sign of any correction.

“Chuck, I think the Service Module’s RCS must be out.”

“Rog,” Jones said. “Houston, we don’t have reaction control, either from the Service Module or from S-NB.”

If the Service Module had blown, it was the end of the mission. But still, the crew ought to be able to get home, from this low Earth orbit.

As the spacecraft rolled, a cloud of ice crystals, sparkling, dispersing, drifted past the window to his right. It seemed to be venting from somewhere in the stack. It was quite beautiful, coalescing above the shining face of Earth.

More alarms lit up, as the problems multiplied and spread.

Donnelly had Surgeon feeding radiation dosimeter readings into his ear on the closed loop.

EECOM said, “Flight, I want to throw a battery on Bus A and Bus B until we psyche out the anomalies. We’re confirming undervolts.”

Donnelly tried to shut out Surgeon’s voice so he could figure out EECOM’s suggestion.

EECOM wanted to run the Command Module off battery power. It was a reasonable short-term suggestion. But, looking ahead, the Command Module’s batteries would have to be conserved to allow the crew to reenter the Earth’s atmosphere. “What about limiting that to a single Bus, rather than both?”

“Hold on that, Flight.” EECOM would be conferring with his team of experts in the back rooms.

It was obvious from multiple indications, not least the crew’s report, that the NERVA had indeed shut itself down after only a few seconds of the planned burn. “Booster, you have anything you want to say to me?”

Conlig didn’t reply. The guy seemed to have frozen out.

“The crew’s health is going to be severely impacted,” Surgeon said on the closed loop. “Though they probably don’t know it yet. In fact, Flight, you can’t expect them to function normally for much beyond a few more minutes.”