It was never easy, Arkady had found, to talk to family and friends from space. Life in space — even on a routine Earth-orbit mission — was rather like a commercial airline pilot’s: hours of tedium, punctuated by moments of extreme terror. If you tried to describe the tedium, it was simply dull; if you talked about the terror, you sounded melodramatic — worse, you might finish up frightening the person who cared about you enough to call you.

It made for awkward conversation.

But his sister knew him, and was wise. Nor would she play the part demanded of her by TsUP.

She spoke to him of simple family matters. Vitalik asked me to say hello, she said. Vitalik was Lusia’s son, Arkady’s nephew. He is at summer camp. He is getting happier. He swims in the sea, he rehearses plays, he is doing arts and crafts. It was different in our day.

“Yes.” At the Soviet pioneer camps when Arkady was a boy, the children had been subject to meetings and political training, so much so they were sometimes deprived of sleep. Not everything about the breakup of the Soviet Union, they agreed, was necessarily so bad. And so on. Lusia spoke further of Vitalik’s small projects and achievements.

She said nothing of his intentions, the fate of the world. She was simply saying goodbye, on behalf of the world, the family he had left behind.

She knew, as he did, that his proposed course of action would mean the final sacrifice. Even if, by some miracle, he survived the landing itself, he could not hope to live through what followed.

But then Henry and Geena were making as big a sacrifice.

There was really no choice.

It was a duty; it must be done.

After a time, they fell silent, and he listened to the soft hiss of the static on the air-to-ground loop.

And eventually, after much debate and protest, official permission was granted to proceed with the mission.

First, Arkady had to change the plane of the orbit of his Soyuz.

At present, the orbit was a ground-hugging circle, angled at some twenty-five degrees to the Moon’s equator, a shallow tilt. Now, Arkady needed a ground track that would take him over the Moon’s South Pole. So his orbit must be tipped up at a more jaunty angle, eighty degrees or more, so that he looped over both poles.

Steering a spacecraft to a new orbit was not a question of turning a wheel, like a car. The Soyuz’s main propulsion system would have to burn at an angle to its present velocity vector, gradually pushing it sideways, like a tug hauling at a supertanker.