“Happy birthday Dad!” said Richard and Hazel together. “Happy forty fifth!” added Richard. “Hope you’re having a good time up there! We're having a great time down here.” To prove it, he produced a bottle of wine and poured himself a glassful, then took a deep swallow.

“I can see that,” said Paul Lewis, laughing. “I hope you’re not driving home.”

There was a speed of light delay of about two seconds as his words were bounced to a newly re-positioned satellite and down to the house in Lincolnshire before Hazel answered. “I'm designated driver for the occasion,” she said. “Don't worry. Me, Len and Cathy'll roll him home when we think he’s had enough party spirit.”

“And I'll make sure he doesn't have too much,” said Cathy, coming into view from the edge of the monitor screen to gently but insistently pluck the glass from her husband’s hand. Richard took a swig directly from the bottle instead before she took that from him as well.

“When are you coming home, Dad?” she asked, taking a three month old baby from her sister’s husband and holding him in the crook of her arm. “This little chap’s never seen his grand daddy except on a screen.”

“It's going to be a while yet, I'm afraid,” replied Paul. “They're using all the available launch windows to replace the satellites that couldn't be saved, it might be months before they can get a replacement crew up here. So long as we're all in good health they've asked us to stay up here a bit longer.”

“Couldn't you fake an illness?” said Richard, grinning. “Say you’re coming down with space lurgy. Just fake a few symptoms. Double vision, headaches, excessive flatulence...”

“You realise they monitor all communications, right?”

After the brief speed of light delay Richard slapped a hand to his head. “Guess I'm not cut out to be a criminal mastermind,” he said. Someone chuckled off screen.

“Who else is there?” asked Paul.

“Apart from mum? Just a few friends...” The sound of cheering came from off screen and a few heads popped into view, some holding drinks, some with party hats on their head. Hands were waved and a chorus of voices wished him a happy birthday. “Thought we'd make a day of it. Any excuse for a party.”

Paul laughed and waved back. “Thank you everyone. Have one on me!” The cheering intensified, then turned into laughter. “I'd like to talk to Mags now, before we lose the slot.”

“Yes, of course. She's in the spare room, so you can talk in private. Well, except for, you know. Anyway, I'll pass you over.”

He leaned forward to fill the screen, pressed a button and his face was replaced with that of his wife, Margaret. Sitting in a chair in front of the spare room computer. “Mags! How you doing?”

She smiled and leaned forward in the chair. “Paul! Happy birthday!”

“Thanks. Everything okay down there?”

“Everything's fine. The kids are fine, they’re both doing well in their jobs. The only thing not fine is you still being up there.”

“Yes, I know I promised I'd be back by now. It's the satellites, They’re using all the launch windows to...”

“I know about the satellites!” She tossed her head angrily to throw her glossy chestnut hair back out of her eyes. “You could come back down if you wanted to. They can’t keep you up there.”

“It'll probably be months before they can get a replacement crew up here. They've asked me to stay a little longer...”

“There are eight of you up there! I watch the telly, I know your operations have all been put on hold until they get everything back to normal. An expert was saying he was surprised you weren't operating on a skeleton crew until then. He said it only takes two people to do the basic housekeeping. The rest of you could come back down. You could just take one of the shuttles and come back down.”

“It's not that simple. We used most of our fuel just keeping the station up in orbit. The engines of the second shuttle are the only way we have of making a course correction if we see a big piece of space debris in our path. They're hoping to get us refuelled as soon as possible, but no-one seems to know when that will be.”

“You have the escape pods!” There was no delay, which told Paul she’d spoken before he'd finished speaking. “You could come down in the escape pods.”

“They're only for emergencies, we can't just take one. I'm sorry. I know I made you a promise, but...”He took a deep breath to calm himself. He hated seeing his wife becoming upset. “I’m afraid I'm stuck up here for a while. A few months at least.”

He looked at the timer at the bottom of the screen. Only a few seconds left. Until they got more satellites back into position there was a limit to how long they could keep the connection open. To conserve the satellites’ limited reserves of fuel, they were putting them into minimal fuel trajectories that would take weeks to get them back to where they were supposed to be. “I have to go now,” he said therefore. “I'm sorry. If there were any way to get back to you, I would, but there's just no way, not yet. I love you.”

She nodded unhappily. “I love you too. Take care up there. Don't do anything dangerous.”

“I won't. I promise...”

The picture broke up, then vanished and Paul found himself staring at his reflection in the dark screen. Then George Jefferson’s face appeared in it. “That's the best we can do, I'm afraid,” the ground controller said. “You'll be over her house in a couple of orbits. You can talk to her directly.”

“No, thanks, tomorrow will do. There's things I have to do. Thanks, George.”

“No worries mate.”

The screen went black again and Paul unstrapped himself from the chair. “I'm going to check the air filters,” he told Zhang Yong, on duty in the control module while Lauren was sleeping. The Chinese shuttle pilot nodded distractedly, then turned his attention back to the system overview monitor.

In space, the dust never settled. Without gravity to pull it down it just floated around in the air, and if it got too thick it could cause breathing problems for the astronauts. All the air was filtered, therefore. Each module had its own filter, sucking the air in and spinning it to centrifuge out the particles of lint, flakes of skin and grains of metal, compacting it into a cylindrical brick that could be removed and packed into a refuse bag for return to earth. Paul had heard that a university student was analysing the stuff as part of his graduate course, but what insights he expected to get was beyond him.

He went to the Colibri shuttle to get the dust canister, then checked the filter in the Vulcan module since that was the closest. Bao was there, doing some routine maintenance work on number two furnace, and he looked up as the assistant commander flipped open the filter’s casing, eased the compact brick of detritus out and opened the dust canister to allow the brick to drift into it. Then he closed both of the plastic boxes with a click of the fasteners, nodded to the scientist and kicked his way into the next module.

He made his way from one to the next, offering friendly greetings to each member of the space station crew as he passed them. He did them in the same order as he always did, that being the best way to make sure he didn't miss one, and that brought him back to the command module last, where he found that Susan Kendall had entered since he'd left. She was staring through the small, round porthole in what Paul tended to think of as the floor, even though there were no floors or ceilings in the weightless habitat. The chairs were all oriented the same way, though, and the pothole was in that part of the hull that was below them when they were sitting in them.

“Just in time,” she said in a flat voice as Paul emptied the air filter. “Come and look.” She moved aside to make room and Paul, curious, pushed himself down towards her. With their heads so close together that he could feel her hair brushing against his, he looked through the four inch thick glass.

“What are we looking at?” he asked.

“You see the horn of Africa?” she said. “Just west of Mogadishu.”

“That's the city on the south eastern coast?”

A reluctant chuckle escaped from the space scientist. “I thought it was we Americans who were supposed to be bad at geography. You see that moving point of light?”

“Yes. What is it?”

“That is Lockyer. My research platform. Burning up as it re-enters the atmosphere.”

He moved a couple of feet away so he could look at her properly. “Oh Susan! I'm so sorry!” She nodded, accepting the sentiment, but didn't seem comforted by it. “If there had been any way to save it...”

“The mule could have saved it. All they had to do was care enough about pure science instead of military paranoia. They saved a spy satellite, you know. A Chinese spy satellite they use for spying on the Indians. As if India is any threat to China.”

“The mule is Chinese, it was rather predictable that they'd use it to safeguard their military assets in preference to everything else. We, Europe I mean, we're always talking about launching a mule of our own...”

“They'd still have used it to save the military stuff first.” She looked back through the pothole. Paul, looking past the untidy tangle of dark hair, saw that the fireball had broken up into several smaller ones. As he watched, they went out one by one, fading like sparks from a fire.

He pulled himself away and returned to the centre of the module. After a moment, she joined him. A tear formed at the corner of her eye and floated away, a small, quivering globule glistening in the module's artificial light. “The only critical phase helium crystals in the universe, gone in a puff of vapour. It took me six months to grow them and I never even had the chance to look at them.”

“You have the camera images...”

“Shut up Paul.” She wiped her eyes with her hand. “I'm sorry,” she said. “It's just that, I was just getting to the point where I could start doing some useful science with them. Just discovering their melting point... You know, there are some theories that predict that they would be stable at room temperature. Imagine being able to hold solid helium in your hand. They could have told us so much! The boring part, the growing them, was over. I spent six months watching them grow, one atom at a time. Six months waiting to get some real work done.”

“Well, maybe it won't take so long next time.”

“What do you mean?”

“Well, there was this theory going around back in the last century. Morphic resonance. It was dreamed up by some chap called Rupert Sheldrake. Basically, he said that the universe somehow remembers how to make complex structures. It may take ages for the structure to form the first time, but next time it’ll be quicker because the universe somehow remembers.”

“That's ridiculous!”

“Says the Christian.”

Susan stared, then turned and kicked herself off from a chair towards the exit to node five. Paul cursed himself for an idiot and reached out to grab her ankle. “Susan! I'm sorry! I don’t know why I said that!”

“Let go of me!”

Paul let go of her ankle and she turned to glare back at him. “My faith is just a joke to you. You mock us, you mock our beliefs...”

“No, I don’t! I really don’t! It's true I don’t believe what you believe but... Look, I don't know if there's a god or not. Maybe there is, who knows? Please, I'm sorry. It was a thoughtless thing to say while you're... While...” He glanced back down at the porthole.

“So it would have been okay to say it at another time?”

“It's just that, you mock Sheldrake for having this ridiculous theory, and it is a ridiculous theory, I admit, but the things that Christians believe, you believe them so completely...”

“So you think it was just a coincidence that the scatter cloud passed by when it did?”

“What, you think God did it?”

“Think about it, moron. If the cloud had passed by just a hundred years ago, there would have been nothing up here to be disturbed by it. It might have passed by five hundred years ago, a thousand years ago, and mankind would have been completely oblivious. Why did it wait until we had hundreds of satellites up here? Coincidence?”

“Well, yes. I mean, we don’t know how common these things are. For all we know, there might be scatter clouds passing through the solar system all the time. Maybe that's what dark matter is.”

“They say the cloud had a total mass of about one per cent the mass of the moon. If things that massive were passing through the solar system all the time...”

“Yes, you're right,” Paul interrupted her. “That was a stupid thing to say, but to think it was the action of some kind of malign intelligence...”

“God is not malign. He loves us. The passage of the cloud must have benefited mankind in some way.”

“Then it’s strange that it’s the only Christian aboard who was affected the worst out of all of us.”

“We have to think of mankind as a whole, Paul. Somehow, the cloud benefits, or will benefit, mankind as a whole, maybe in a way that won't become clear until hundreds of years from now. And it wasn't God who lost me Lockyer. It was the asshats in Beijing who could have saved it and chose not to.” She kicked herself off again and swam through the hatch, leaving the assistant commander staring after her in dismay.

“It's not her fault,” said Zhang Yong, whom they'd both forgotten was there with them, at the other end of the module. “In the USA these days, everyone's either Christian or pretends to be. You could try being a bit more tolerant, though. Your kind of militant atheism just turns potential friends into enemies."

"What are you talking about? I admire her, respect her..."

“Is that what you were giving her just now, admiration and respect?”

“It just seems extraordinary to me that, I mean, she's a very intelligent woman whose risen to the very top of her field. You know how many people try to become astronauts and how few succeed. You have to really impress the judges to get up here. I always knew she called herself a Christian, lots of people do. It's just something they write on forms when it asks them for their religion. I suppose I just assumed she was the same.”

“But she’s not, is she?”

“Bao told me that... He thinks she's an actual creationist. Young earth, six days, talking snakes, the whole thing. Do you think that's true?”

“I wouldn't advise asking her. She probably wouldn’t take it well.”

“Yeah. I can probably never talk to her about religion again without her thinking I'm mocking her. Better to just avoid the whole subject. I'll find something else to talk to her about and, hopefully, the whole religion thing will just fade and be forgotten.”

“I suppose there's a chance of that.”

Paul chuckled. “Yeah, you're right. Snowball’s chance in hell, right? I suppose that’s something else she believes in, Hell. And that I deserve to go there.” He gave a heavy sigh. “Do you have religious beliefs, Zhang? What do the Chinese believe in?”

“China has many religions. There are Chinese Christians, Chinese Buddhists, Chinese Moslems. I myself was raised as a Taoist.”

“I really don’t know much about... “ Paul spread his hands helplessly. “Does Taoism have gods?”

“No. It's more of a lifestyle really. We try to achieve perfection by becoming one with the rhythms of the universe. I can give you some books to read if you like.”

“Later perhaps. Look, I’d better go find her. See if I can patch things up between us.”

“Good luck. Oh and don't forget the de-humidifier needs fixing. We don’t want mold growing on the walls.”

“Don't worry, I'll get to it.” He kicked his way out of the module, following after Susan.

He went back to the Colibri shuttle again first to drop off the dust box, then went looking for Susan. He found her in the biology module calibrating a centrifuge, a look of stoic calm on here face. She looked up as he entered, then turned back to her work, pointedly ignoring him.

He went over to the rodent habitat and pulled the first compartment out of the wall. Inside, twenty white mice were clinging by their claws to the strips of gauze strung across the main open area, which allowed them to move around quite happily, as though they were still back on earth. He opened the door in the side, reached in and gently took hold of the nearest mouse, removing it and closing the door again.

“When you've finished what you're doing,” he said, “Could you give me a hand with this?”

Susan grunted a reply. She would, he knew. She was too professional not to, and doing a job together was the best way he knew to move on from an argument. Strictly speaking, looking after the rodent colony was Jayesh Gudka's responsibility, but handling the mice was a fun job and he'd agreed to let everyone take turns. That made it the perfect task for this occasion. Paul needed something that two people could do together, forcing them to work together when one of them would rather have been alone. Forcing them to engage in conversation. Hopefully, but the time they’d finished, the argument in the command module would be forgotten and they'd be friends again.

A few minutes later, therefore, when she’s finished with the centrifuge, Susan came over and removed another mouse from the compartment, putting it in the centrifugal scales to weigh it and then touching its tiny feet to the biometric sensor, a tiny miracle of technology that simultaneously measured its temperature, its bone density, its blood pressure and glucose levels and half a dozen other things that, together, would allow the experts down on earth to assess its general state of health. A larger sensor in the medical module did the same for the human astronauts.

The mice were the fiftieth generation descendants of the dozen rodents who’d been launched into space twelve years before as part of an ambitious experiment to study the long term effects of microgravity over many generations. Other experiments like it had been done before, but this time they were hoping to continue to breed the rodents in space for a full twenty years. It was expected that, one day, there would be human children born in space, in massive space habitats having populations of several thousand people, but before that could happen it was important to know whether the descendants of those colonists, several generations later, would suffer any lasting ill effects. Every time a shuttle returned to earth it took some of the mice with them, to be bred back in a normal gravity environment, and the last Paul had heard they'd been breeding for several generations without showing any signs that their ancestors had ever been in space.

“Come on, little fella,” he said as he reached for the last occupant of compartment one. They'd all been handled many times before and were well used to it, but for some reason this one was suddenly reluctant to have its health checked and kept scrabbling along the strips of gauze away from Paul's reaching fingers. Paul was quite glad of that, though, because it gave him something to say to Susan.

“Been eating too many cakes, have you?” he said therefore, glancing across as Susan to share the joke with her. “Is that why you don’t want to be weighed?” Susan smiled back out of politeness but said nothing.

“You can run but you can't hide,” said Paul, making another lunge for the rodent. “I think this is a game for him. He's enjoying this.” Still no reply from the other astronaut, but at least she would know now that he was trying to make things right with her. Even if she wasn't ready to forgive him yet, he could hope that forgiveness would come at some point, perhaps tomorrow or the day after. However long it took for her wounded feelings to recover.

“Gotcha!” He cried triumphantly as his fingers closed around the reluctant mouse. He removed it from the compartment and read the tag fastened around its ankle. “Convict number 110125. I hope you know you've just blown your chances of parole. In fact, I wouldn’t be surprised if you get the chair for this.”

“I thought you Brits didn't have the death penalty,” said Susan, glancing up at him again.

Paul felt a surge of hope. “We make an exception in the case of exceptionally annoying miscreants,” he said, carefully placing the mouse in the cage that was attached to the end of the centrifugal scales’ rotating arm. He pressed the button and the arm rotated twice before stopping again. Paul noted the figure that appeared on the display, wrote it down on the record sheet and removed the mouse, which twitched its nose at him. “Thirty seven grams. I knew it! They've been smuggling food in. I suspect an accomplice on the outside.”

“Jayesh overfeeds them,” said Susan, placing the mice back in their compartment one at a time. She then slid it back into its alcove, flush with the wall. Twenty tiny white faces peered out at her. “I've warned him about it. If they get too overweight he risks invalidating the whole experiment.”

“He's due to go home on the next shuttle, whenever that is. We can indulge the little fellows that long. It's not like they're massively overweight. Thirty seven grams is just on the high side of normal.” He tapped the transparent plastic with the tip of his fingernail. The mice just twitched their noses at him.

“So does that mean you won't be bringing a criminal prosecution?”

“I think we can save the taxpayer’s money just this once and let them off with a warning.”

“We should get some activities for them. A ball or something. They must get bored in there.”

“Mice gnaw things when they're bored. These chaps don’t show any signs of being unhappy. All a mouse wants to do, really, is eat, sleep, poop and shag, and they can do all those things in there.”

“They’re not all that different from men then, really,” said Susan, and this time there was a glint of amusement in her eyes as she glanced sideways at him. Paul’s heart leapt with jubilation and relief. She’d made a joke! She'd forgiven him! They were friends again!

“Not quite,” he said. “We have beer as well. And football. You're right, a ball would be a good idea. There's never been an animal that didn't enjoy playing with a ball.” He then pulled the second compartment from the wall and opened the door to remove the first mouse.