Sixt had actually completed seven flights already and was hoping for more. He was an obsessive learner, having taken at least five degrees in with his two-year stretches of Shuttle training. He was undeniably old: he was totally bald, his head and face seemingly polished smooth. He moved with an odd gait, as if awkward in Earth’s gravity, and — like others of his generation — he was, Geena thought, rather clumsy and too brief in his public pronouncements, not so articulate and media-friendly and practised as the rest of them, even Geena. She wondered briefly how they must all look to outsiders: like younger, slimmer, ethnically mixed versions of the Center director maybe, sleek and rich-looking and confident and articulate. The epitome of space travel as a career move.

It was for the sake of this corporate cosiness, she thought with uneasy regret, that Henry’s mission had been broken, Sixt fumbled with his lapel microphone. “You ask me about regrets. We weren’t ready to go to Mars, I understand that now. Spaceflight is not easy. I don’t know personally how I would have fared, psychologically, if, in some other universe, I had ever gotten to do that hundred-million-mile trip to Mars. Months of isolation from my family and home, not just days…”

Sixt, do you still think we should go to Mars?

“Well, I guess so. But it remains a heck of a long way to go. I’ve come to think we should put our hearts into a return to the Moon. Sure, the Moon’s not an ideal destination. It’s a desert compared to Mars. It would be better if Mars was in orbit around the Earth, just three days away, but it isn’t, and we ought to make the best of what we got. But even on the Moon it might be possible to live off the land, if we’re smart enough.”

And then came the questions for Geena. The first couple were about her last flight but two, the first by an all-woman crew in US space history. It seemed to have aroused as much interest and curiosity as if NASA had appointed a team of chimpanzees to make the flight. But Geena had gotten used to handling those questions now.

After that, they got tougher.

Your husband thinks there’s an ocean on the Moon, doesn’t he?

Gentle laughter.

“Not an ocean.”

But enough to flood the Moon, if it was all melted. Is that right?

“It’s a possibility.” She smiled tightly. “I don’t pretend to understand the theory of how it got there. But it seems possible.”

Geena, do you think NASA should have brought the astronauts home from Station?

“No. The evidence we have is that the radiation pulse from Venus was transient. The danger’s already over…”

Geena, I can’t help notice Dr Meacher isn’t here.

Sixt tried to help out. “Nor are my ex-wives. Attendance isn’t compulsory, thank God.”