Still, she remembered now with an odd tug of nostalgia, it was at the Washington symposium that she’d first met Henry. A wild-eyed geologist with some kind of sketched-out scheme for extended lunar colonies, self-sufficient cities of lunar glass big enough for thousands of people, fuelled by all the ice he believed existed at the Poles. Even then he talked about terraforming the Moon.

Those eager youngsters lobbied hard, and got NASA to set up an Office of Exploration which looked at ways to return to the Moon and push on to Mars.

“We spent years devising mission architectures,” said Frank, nostalgically. “All those imaginary voyages. Christ, we could have piled up the vu-graphs we generated and just climbed to the Moon.”

“But then came Challenger,” Jays said brutally. “And that was the end of that.”

“Yeah. We didn’t even fly again for two years. And all the plans we had were frozen…”

“I was there when Bush made that speech at the Air and Space Museum,” Jays said. “Twenty years after Apollo 11. The Space Exploration Initiative. We’d finish the Station, go back to the Moon, on to Mars. But we screwed ourselves. NASA came up with a report that said it would take half a trillion dollars to get to Mars. And Congress killed it, zeroed out the budget by “91, “92. The OTV was cancelled—”

“They even killed off the Lunar Polar Orbiter,” Frank said. “An unmanned probe, that we’d been studying for twenty years. What a waste.”

“Which is why I say,” Jays said to Geena, “we’re further away from the Moon than we were in 1961…”

Geena leaned forward. “Okay. I heard how cruel life is. I heard how hard it is to achieve this. Now tell me how we do it.”

Frank looked up at her. “Five weeks?”

“Five weeks.”

His eyes, hooded by his thick spectacles, narrowed.

“The logic of how you get to the Moon hasn’t changed since 1969,” said Frank Turtle.

Frank started sketching on the back of a napkin: schematic mission profiles with the Earth shown as a flat floor, the Moon as a ceiling above it, and little rockets and landers clambering between the two, like medieval angels flying between Heaven and a flat Earth.

“You need some way to get to Earth orbit, or beyond. Then you need some kind of transfer vehicle, to drive you to the Moon. You need a habitat to sustain you on the journey. And you need some kind of lunar lander, like Apollo’s, to drop you to the surface and bring you back up again. For an extended stay you probably need to double all that, to drop a shelter or surface-stay resources in place.

“Now, Earth’s gravity well is deep. If you want to send a ton to the Moon, you need to throw seven tons from Earth’s surface, most of it lox propellant. Which is why we needed a Saturn V for Apollo.