Geena was scrabbling in a locker. “Christ, Henry.” She handed him a plastic bag, and he held it before his face, catching most of the rest.

Under some complex combination of surface tension and air currents, the loose sphere of puke split in two. One half headed for the wall, the other for Geena.

Henry ventured, “Kind of pretty, isn’t it? And look at the way they are moving. Equal and opposite. Conservation of momentum, I guess. And—”

Geena was watching in horrified fascination. She didn’t seem able to move out of the way.

The blob hit her square on her chest. The magic of zero G dissipated instantly, and the puke spread out over her white T-shirt, viscous, sticky and lumpy.

She started dabbing at it with wet towels. “Henry, you asshole.”

“I never said I was a spaceman.”

The other lump of vomit reached a locker door now. Instead of sticking, it broke up into a dozen smaller globules, that rebounded and set off over the cabin.

Arkady came floating up from the descent module. “I could smell — oh.” He laughed. “Time to hunt butterflies, I think.”

He took a handful of wet wipes, and he and Geena started to chase over the cabin, snagging the vomit spheroids out of the air. Henry just hung there being still, trying not to worry about which way was up.

Twenty-eight hours out; a hundred and forty thousand miles from home. A day after TLI, they were already more than halfway to the Moon.

Wrapped in a blanket, Henry hung before a window, staring out.

He could see the Earth every once in a while, as it slid past his window. He could tell it was a fat round world, floating in space, much more three-dimensional than the Moon; the huge highlight cast by the sun from the oceans ensured that, as if the Earth was a huge steel ball under a spotlight. Every time the planet came by, it dwindled. He couldn’t see the change if he watched, but if he turned away from it and looked back, it was a little smaller and more distant.

Now, with the planet reduced to the size of a baseball, he found he’d lost his sense of what he was looking at. He was supposed to be a geologist, for Christ’s sake. But the real Earth was no map: it was swathed in cloud, and the countries weren’t colour-coded.

Geena laughed at him when he told her this.

“Start from the beginning,” she said. “What’s that big white patch at the edge? Ice or clouds?”

Henry thought about it. “Looks like ice,” he said. “And if it’s summer in the northern hemisphere, and that patch is in sunlight—”

“It has to be the Arctic.”

“Okay. But how can that be right when it’s at the bottom?”

Geena, reasonably gently, took hold of his longjohns at the hips, and swivelled him around, handling his mass as easily as if he was some inert piece of payload.

When she’d turned him upside down, everything fell into place. There was Antarctica, and above it there was South America, Chile to Brazil, from forest to desert swathed in clouds. The whole of North America was drowned by grey, unseasonal cloud, although he could see Florida peeking out through a rift. There was a cyclone over the mid-Atlantic, like some immense pinwheel. In the Caribbean, he could see the Bahamas, the shallow ocean there shining green-blue as if lit from within.

Monica Beus had e-mailed him with extracts from newscasts, some still uncensored.

—French government have announced that their nuclear strike against a deliberately engineered Moonseed patch in the South Pacific has not been—

—hard to believe that these hollow-eyed, malnourished children are English—

—the Internet shutdown may indeed be purely from technical issues. But civil liberties groups are saying this is too convenient an excuse for a Government which is demonstrating increasingly illiberal instincts in this time of crisis—

—relocation of crucial high-tech companies from the Washington coast has been complicated by the grounding of many aircraft by volcanic ash—

—we should talk to it. It’s a living thing. This is first contact, for God’s sake. What does it want?—

—so this thing chews rocks. Well, so does my ex-wife, and I lived with her for three years before—

He deleted the mail before he got to the end. It was hard to reconcile the geometric calm and silence of space travel with the clamour of voices on Earth, crying for help. He couldn’t help a guilty feeling that — despite the unknown dangers he faced ahead — he had already escaped.

He wanted to be able to pick up the Earth and turn it around, view it from the other side, witness an African night. But he would have to wait for that; the Earth would turn in its own sweet time, as it always had, and by the time Africa was brought to face him, he would be too far away to be able to see.

Arkady showed Henry the food store.

The Russian-cuisine food was kept in boxes in the lockers of the orbital module. There seemed to be a lot of soup. Some of it was freeze-dried — kharcho, for instance, spicy lamb and rice — and some was natural liquid, such as borscht, which seemed to be cabbage and beet. There was cottage cheese, pork with potato, canned fish, coffee, tea, milk. There were eight different kinds of bread, cut up into little chunks, and then candied fruits, plums, chocolate, cookies. To drink there was fruit juice, in tubes, and coffee and tea. It was a regular snack bar up there.

It took Henry a day to get his appetite back — he still didn’t feel too hungry even so — and he took to taking what he wanted, when he wanted, and stuffing his pockets with snacks for later.

He got in trouble with Geena, for scattering crumbs around the capsule. The Soyuz, it seemed, didn’t have a decent air filter system, and he had to go around the cabin, scooping the drifting crumbs out of the air with a handheld vacuum cleaner.

Geena showed him how to wash, Russian-style. You just had to wipe yourself down with wet napkins. You could even wash your hair that way: Geena wrapped a brush in another napkin, and scrubbed over his head for him. It was a soothing, relaxing feeling. Grooming rituals, he thought, a hundred and forty thousand miles from the nearest chimpanzee colony.

Shaving was just an electric razor; he had a little vacuum cleaner standing by to collect his spare whiskers. He cleaned his teeth with a napkin wrapped around his finger. It was loaded with mint-flavoured toothpaste; it got rid, at last, of the taste of vomit from his mouth. Geena said it was actually good for him because it meant his gums got a massage too.

Besides, toothbrushes would be impractical up here. After all, where would you spit?

Ultimately, he had to face it, he needed a dump.

Once again he faced a 1960s Soviet-era privy, mounted on the wall. He stripped off his longjohns, switched on the fan, held himself in place and pushed.

He had to strain harder than he’d expected; it seemed that Earth gravity even helped with this simple act.

It wasn’t so bad. One little floater escaped the air flow, and he was able to chase it down with a wet wipe.

At that, Geena told him, it wasn’t as bad a system as what the first Moon voyagers had to endure on Apollo, which was after all the same era as this Soyuz design. On Apollo, a crap involved stripping stark naked, and climbing into the storage bay under the three metal-frame couches. Then you took one of a collection of plastic bags, with adhesive coatings on the brim, and finger-shaped tubes built into the side. You had to dig into the bag with your, finger — nothing would fall, after all — and hook your turds down into the bag. And afterwards you had to break open a capsule of germicide, drop it into the bag, and knead it all together.

Things, Henry realized as he chased down his turds, could be a lot worse.