And they’d have to perform the burn during the loss-of-signal period, while the craft was around the back of the Moon and shielded from the Earth. So there would be no way the men in Mission Control could help them out.

Since his decision to initiate it, Bert Seger had built up the mission, orchestrating the media coverage carefully. Apollo/Moonlab was going to be a feelgood extravaganza, a return to the Moon, a demonstration of competence: a distraction from the collapse of Saigon, the rocketing cost of fuel, the stagnant economy, inflation… He’d even given way to a write-in campaign by Star Trek fans who wanted Enterprise as the call sign for the ship, the first Apollo to the Moon in four years. It didn’t do any good for the Astronaut Office to protest that they didn’t need a call sign for this mission.

It was all fine PR. But the high profile meant that a failure — and a failure caused by some dumb programming fault — would be very embarrassing.

Apollo shuddered slightly, and solenoids rattled. That was the firing of the reaction control clusters, halting the spacecraft’s slow roll. The stack had been rotating since leaving Earth orbit, to even out the sun’s heat; the crew called it “barbecue mode.”

Stone, in the center of the three frame couches, said suddenly, “Hey. I got the Moon. Right below us.”

Dana looked up from his checklist.

It looked as if streams of oil were descending across the glass of the window to Dana’s right. Dana felt a stab of fear; he couldn’t figure what malfunction could have caused that. Then his eyes refocused, and he realized he was looking at mountains. They slid slowly past the window, lit by the slanting rays of the sun, trailing long black shadows.

The mountains of the Moon. “Oh, Jesus. Look out there.”

“It’s only the fucking Moon,” Jones said. “You’re going to be seeing it for a long time. Come on, get back to your lists. Thousand miles out. Six and a half thousand feet per second… We’ve fifteen minutes until LOS, twenty-three minutes from the LOI burn…”

The sun was hidden behind the orb of the Moon, Dana saw, and the Moon was backlit by the corona, the sun’s outer atmosphere. So there was light all around the Moon, as if the far side were on fire. But Dana could see the shadowed side quite clearly; it swam past the window, illuminated by Earthlight, ghost-pale.

The Moon looked like a ball of glass, its surface cracked and complex, as if starred by buckshot. Tinged pale white, the Moon’s center loomed out at Dana, given substance by the Earthlight’s shading: the Moon was surprisingly three-dimensional, no longer the flat yellow disk he had known from Earth.

He picked out a large, deep crater; perhaps it was Tycho.