"Which one's the sun?" asked David Birch.

     Andrew Birch looked up into the sky. A million stars shone with impossible clarity, dazzling bright against the velvet blackness that separated them. His breath momentarily fogged the interior of his faceplate, but the heating elements, the invisibly fine strands of silver that lay between the layers of transparent silica, made it evaporate within less than a second, restoring his pristine view.

     "Ask your suit to highlight it for you," he said. "It'll put a pair of crossbars on your visor display."

     "Suit," said the boy. "Please show me where the sun is." There was a pause before the ten-year old spoke again. "I can see the crosshairs," he said, staring up into the sky, "but there's nothing inside them."

     "That's because the suit's keeping you from seeing it," his father replied. "It's too bright to look at directly, even at this distance. Your helmet's protecting your eyes. Two clusters of polarised elements in your faceplate, one in front of each eye, form tiny spots of black that block it from view. They move as you move your head, always keeping you from seeing it." Andrew heard him curse with disappointment and chuckled with amusement. "Six billion kilometres away," he said. "That's a long way, but it's still close enough to give us about half a watt of energy per square metre. Still close enough to hurt your eyes."

     The boy nodded thoughtfully, then lost interest in it and began picking his way across the hard nitrogen ice that covered the ground. The cleats on the soles of his boots scratched away at the surface layer, stained blue with impurities, to reveal the colourless white of the pure nitrogen beneath. The occasional tiny fragment of ice that he kicked up from the ground fell again as fast as if it were made of lead.

     "Stay in the light of the headlamps," his father warned. "And don't go too far."

     "We've all got our beacons on," David replied. "I can't get lost."

     "There might be crevasses or sharp outcrops of ice where it's shifted," his father replied, watching after him anxiously. "If you fall, you could tear the fabric or burst a heating pipe. If you lose the heating in your leg, your whole leg might be frozen solid before we can get you back inside..."

     "Dear," said the voice of Susan, his wife, over the intercom. "Don't fuss. You'll give him a complex."

     "I just want him to understand the dangers," Andrew replied. "The surface is unforgiving. It's constantly looking for ways to kill us."

     "I'll be careful, dad," David promised, picking his way carefully across the flat, featureless plain. The surface walk for which he'd been begging for weeks. A large part of Andrew wished he hadn't agreed to this, to let his son leave the safety of the hab-rover. but the truth was that the boy was long past the age where he should have had his first walk on the surface. Some kind of accident or emergency could occur at any time that would require him to leave the rover, and he needed to know what to do. How to put on a surface excursion suit for himself. Perform all the checks, go through the startup procedure and operate the airlock. This time, his father had done it all for him, but next time the boy would do it for himself while his father watched with even greater anxiety than he was feeling now.

     The boy was looking up into the sky again. Understandable, his father knew. All his life, he'd lived in the tunnels and caverns of New London. There's been the occasional trip in a hab-rover as his father's work took him here and there across the frozen world, but even then there had been a ceiling of steel and aluminium above him. Now, though, there was nothing but a couple of millimetres of fused silica between his bright, hazel eyes and the rest of the universe.

     Andrew envied him. He, Andrew, been only five years old when a broken axle had forced his family to leave their hab-rover and get a lift back to the city. Too young to really understand what was happening and appreciate the walk across the uneven, icy ground to the rescue vehicle. Having been outside once, his father had then thought nothing of taking him with him on many other occasions, so that by the time his ability to appreciate new experiences had fully matured the surface of their world had become totally familiar to him. David, on the other hand, was getting it all in one go and it would take him a while to process all that he was experiencing.

     Suddenly there was darkness where David had been standing and Andrew spun around in alarm. "David! Where are you?"

     "It's okay, dad," the boy replied. "I just turned my helmet light off. I wanted to get a proper look at the world."

     Andrew sagged with relief. He'd done the same thing during one of his first trips to the surface. With one's helmet light on, the brightness washed out everything else. There was only pitch blackness outside the small puddle of light it spilled on the ground, but if you turned it off and waited for your eyes to adjust to the darkness...

     Even from six billion kilometres way, the sun lit the landscape as brightly as a darkened room with the curtains half closed. Hills, even mountains, could be seen on the horizon; a dull, slate grey against the star speckled blackness of the sky. The vista stretched an impossible distance. Distances that couldn't be imagined when the insides of tunnels, caverns and roving vehicles were all you had ever known. Even virtual reality didn't prepare you for it. Andrew knew what his son was experiencing, therefore, and was prepared to cut him a little slack for that reason.

     Only a little, though. This was still the surface, and the surface was always looking for ways to kill you. "That'll do now," he said therefore. "Turn your helmet light back on now."

     "Just a little longer," his son protested.

     Andrew began striding anxiously towards him. There was vapour beginning to rise around the boy's feet, he saw, where even his superbly insulated boots couldn't keep a little heat from leaking out. "Walk around," he said. "Never stand in one spot too long. Remember your training."

     "I'm getting cold," David complained.

     "You're losing heat from conduction, it's all the vapour around you. Walk around."

     David did so, and Andrew relaxed as the boy turned his helmet light back on again. He saw his son wanting to run, to take advantage of the wide, uneven surface around him. Back in the city there were wide open spaces, caverns dug large enough to give the illusion of being outside, but the ground was always flat. Tiled walkways or neatly trimmed grass. Here, though, there were hummocks to run up and hollows to jump over. And jagged outcrops that a running boy might trip over causing him to tear his suit or shatter his visor. A tempting element of danger that few children could resist. Andrew tensed himself to give chase if his son did suddenly take off, therefore, but to his relief the boy restrained himself, climbing a low rise to see what lay beyond, only to turn back when he saw only darkness.

     "Come on, David," said Andrew. "Time to do what we came out here to do."

     David reluctantly turned back, retracing his own footsteps, the white scratches in the blue ice, the way he'd been taught. Following the path that had been proven to be free from threats and dangers. Only when he was three quarters of the way back did he turn aside, heading not for the familiar bulk of the hab-rover but for the smaller structure that stood about fifty metres from it. The life hutch. A safe refuge for anyone who, for one reason or another, found themselves marooned on the surface without transport back to the city. A place where they could wait until help arrived.

     It was a bright orange dome with a flashing light on top, located at the top of a low hill beside the road. Easy to see from a distance. Andrew paused in front of the door until his son had joined him there, skipping and jumping the last few steps in his happiness.

     "What are the numbers for, Dad?" he asked.

    He was pointing to the serial number printed above the door. B-0018208. "That's so we can tell which hutch it is," Andrew replied. "There's a radio inside, of course, or there's supposed to be, and the computer automatically adds a location tag whenever it's used so the rescuers know which hutch the message is coming from. If the hutch's radio isn't working for some reason, though, as it isn't here, and the refugee has to use his own radio, he can give the serial number to tell the rescuers where he is." The boy nodded seriously.

     Andrew turned the wheel in the airlock's outer door and pulled it open. He stepped inside and David squeezed in with him. There was just enough room for the two of them. "Everything okay over there, Sue?" he asked, glancing out at where he'd left the hab-rover, parked on the road of overlapping wheel scratch marks in the ice.

     "Fine, Andy," his wife replied.

     "Okay. Be back soon."

     "Take all the time you need. We're fine over here."

     "Okay." Andrew closed the door and the tiny chamber automatically began to pressurise.

     It took a couple of minutes for his visor display to tell him that the airlock was fully pressurised, but as soon as the small blue light lit up father and son unlocked their helmets and took them off. "The air's cold," said David curiously, his breath making a cloud in front of his face. It was the first time he'd ever felt cold air on his skin.

     "A lot warmer than it is outside," his father replied. "Let's get inside." He opened the airlock's inner door and stepped into the hutch.

     It was small but cosy. A single room with two padded cots, a table with two chairs and a row of cabinets along the far wall. The computer terminal was mounted on the wall beside the airlock door, below the window that gave a view out over the surrounding landscape. Andrew looked out at the hab-rover and saw his wife looking at him through the cockpit window. They waved to each other, and then Andrew turned, eager to get down to business.

     "How often do hutches go wrong?" asked David, staring around the room in fascination. He started opening drawers, looking down at the medical supplies, bottles of water and packets of preserved food. Enough to last two people for two weeks. It was getting warmer in the hutch as the heaters responded to the presence of two living people.

     "Not too often," his father replied. "The latest ones are very reliable, or at least they're supposed to be. There's nothing in the environment that can damage them. No running water to cause corrosion. No animals to chew cables. Theoretically, you set up a piece of equipment here and it can keep on running in perfect condition for hundreds of years."

     "So why didn't it?" he muttered to himself as he sat down at the computer terminal. He called up the diagnostics menu and scrolled down until he came to the communications sub-menu. There was a list of items, all ticked green, except for one that had an angry red cross beside it. Satellite connection. He clicked on it and another menu appeared beside it. He clicked on the one that said 'Establish alternate connection'.

     He turned on his suit radio. "Sue? You there?"

     "Right here," his wife replied. "You okay?"

     "Fine," Andrew replied. "Can you turn on the rover's hub function? I want to try using the rover as a relay. Pick up signals from the hutch and pass them on to the satellite."

     "Sure," she replied. There was a short pause. "Done," she said.

     "Thanks, Hon." A new message had appeared on the computer screen. 'Hub found. Connect? Y/N' Andrew clicked on the Y and the red cross turned into a green tick. Andrew nodded with satisfaction. That told him that the hutch's computer and software was working properly. The problem must lie with the hardware. Maybe something as simple as a wire coming loose. He took a screwdriver from a pouch and began unscrewing the wall panel behind which the wiring ran.

     "Can I go outside again?" asked David, standing in front of the airlock door.

     "Wait until I'm finished," his father replied. "Then we'll both go outside together. You can play as much as you like until your air gets low."

     "I can send James out to keep an eye on him," Susan suggested over the radio link.

     "James isn't much older than David..."

     "I'm fourteen!" the boy protested indignantly, his voice indistinct where it was picked up by his mother's headset. "I'm better on the surface than you are."

     "I could go," another voice suggested. Jasmine, their sixteen year old daughter. "I'm not doing anything."

     "You know the regs," Andrew reminded them. "Only two people outside the rover at any one time. The rules exist for a reason. The surface is dangerous, no matter how used to it you might think you are."

     "Technically, you're not outside," Susan reminded him, though. "You're in the hutch."

     "Please don't argue with me, Susan," said Andrew irritably. "I'm just thinking on your safety."

     "He's right, children," said Susan apologetically. "If your father says no..."

     "Son of a bitch!" swore Andrew suddenly. He'd taken the wall panel off and gotten his first glimpse of what lay on the other side. There was no damage. Instead, one of the wires had been carefully disconnected from its terminal and was dangling freely. All Andrew had to do to restore the hutch's satellite link was place it back in its socket and tighten the small screw that held it there. On the bare steel wall behind it, someone had written a short message with a crimson marker pen. It read 'Our only future is on Earth'.

     "Bloody remainers!" Andrew swore again. "They brought us fifty klicks from the dig site just to send a message that I have to include in the official report."

     "They actually sabotaged a life hutch?" said Susan. Andrew could hear the shocked tone in her voice.

     "If they'd just scrawled it on the wall we could have just ignored it," her husband replied. "This way, though, it becomes official. The message gets all the way to Tembo's inbox."

     "So Tembo will just ignore it," said Susan. "They've still accomplished nothing."

     "They accomplished costing us two days of work," said Andrew angrily. "Also, what if someone needed to use the hutch? Maybe injured, his body partially frozen. In no condition to perform a repair, no matter how simple and easy. They could have killed someone."

     He looked around to see David staring at him, disturbed by his father's anger. "It's okay, Davey," he said, going over to him and tousling the boy's hair. "I'm just a little tired, that's all. This is good news, really. I thought I might have to spend hours searching for the fault, but all I've got to do is reconnect one little screw." The boy grinned, his good humour restored.

     "I've a good mind not to put this in the report," he said as he went back to work with the screwdriver. "Deny them the publicity they want. I could say it was just a blown fuse or something."

     "Andy, no!" his wife warned him, fear in her voice. "Falsifying a repair report..."

     "Yeah, I know," he replied with a sigh. "It was just a thought. Maybe we can catch the perpetrators, though. Trace who's been this way during the past couple of days."

     "They'll have turned off their transponder," Susan replied. "And they'll have accomplices to cover for their absence from the city."

     Andrew nodded glumly as he tightened the screw holding the wire in its socket. "Okay," he said. "Turn off the rover's hub function. Let's see if the hutch can make contact with the satellite on its own."

     The green tick turned back into a red cross for a moment, but then the green tick returned. Andrew had the life hutch send a couple of test messages to New London to test the connection, then began screwing the wall panel back in place. "Done," he said in satisfaction when he'd finished. He packed his tools away in his belt pouches, then stood.

     "Okay, champ," he then said, turning back to his son. "Put your helmet back on. Time to go."

     Outside the hutch, Andrew paused for a moment, looking down at the ice covered ground. The people who had installed the life hutch, a decade or so ago, had left the ice scratched to hell as they'd walked and driven heavy machinery over it, and with no atmosphere to stir things up the impressions remained as fresh as the day they'd been made. Even so, though, he wondered whether the tracks left by the remainer could be made out from the rest. Theoretically, he should be able to track the man, or the woman, back to his own rover and then follow its wheel tracks all the way back to wherever it was now. Probably safely back in the city, he knew, but if, by some chance, it wasn't... There were thirty or so hab-rovers currently on the surface, he knew. Most of them out on their own with no-one to check whether they were really where they were supposed to be. He could track down the culprit and make him answer to the authorities for what he'd done...

     His son was staring at him, though, silently begging him to join him for some fun on the surface, and catching irresponsible fools wasn't his responsibility. To hell with it, he thought. One disconnected wire wasn't that big a deal. Let someone else worry about it.

     He reached down and used his gauntleted hands to gather up some of the scratched up ice. Heat leaking through the heavily insulated fabric immediately made it start to vaporise, chilling his hands. He squeezed it into a lump, applying pressure, pushing the nitrogen past its triple point so that some of it liquidised, gluing it into a snowball. He threw it at David who shrieked with joy as he ducked. The chunk of crushed, slushy ice hit him on the shoulder where it shattered into a cloud of glittering shards that fell to the ground like bricks.

     "It's war!" the boy cried, reaching down for his own handful of ice while his father similarly re-armed himself, and a moment later the snowball fight was in full swing.