Do you have any idea just how big space is? How empty? How lonely? I bet you don't. Maybe you know that the Earth is 92 million miles from the Sun, and that Jupiter is 500 million miles. But how many people truly have a handle on how fucking enormous that is? Not many.

The shops are a mile away. That is reasonable - it takes you fifteen minutes to walk there. Your friend lives ten miles away. That is reasonable – your car can drive you there in a few minutes. But see what we did? We added a layer of abstraction from the real world. You are isolated from the actual distance by your car, which does the work for you. You are beginning to lose touch with the distance already. One hundred miles is the distance to the next large city. That takes over an hour on good roads. Another layer of abstraction – we have these asphalt shortcuts that help reduce the distance and time. You use music to pass the time, the hour flies by without you noticing. We have abstracted time now, too. One thousand miles means that you go to the station and catch a train. Now you hop from point to point, insulated from the terrain rushing by at a significant fraction of the speed of sound by a quartz window on a silver bullet floating on a magnetic cushion. You arrive a couple of hours later, unaware of the distance you have covered. Houses, roads and rivers and hills have all been bypassed, pushed to the side of the track’s gleaming, razor-edged path. Ten thousand miles – you take a jet, drift in out of consciousness, the movies and a glass of cheap red wine fills the fleeting moments you have awake. You flit over mountains, cities, seas and oceans as if they were merely cracks in the stone pavement on the way to the shops all that time ago. You arrive, nearly at the other side of the planet, as if you had barely moved. You have no sense of the scale of the journey you made, let alone the hunk of rock that stands between you and the home and shops you left only a few hours ago. You can go little farther on our little world without beginning to return to your starting place. We now abstract again – one third of a million miles in a tin can gets you to our Moon. You have no sense of your velocity as you hurtle against the formless void, punching you world-lines out of the sphere of the Earth. But now you have gone 30 times further that your previous intra-aero journey, to a new world. You didn’t even notice – a week later you return to Earth, with only a rock or two to show for your reach to the stars. Now scale up over one thousand times to the distance to Jupiter. You have absolutely no concept of the relation of this to the walk to the shops to collect your newspaper and a bread roll for lunch. This scale is incomprehensible to the human mind – to fully embrace the emptiness is to stare into the infinite eyes of an Empty God, to release your soul to him, to dwell forever in nothingness. To know space is to know madness.

So, imagine how I feel now, by myself, halfway (one divided into two; I can at least deal with this number) across this inhuman expanse, floating in my box, unaware of the thousands of miles being stripped from the journey by the minute. It is so quiet out here. I have not seen another human for two weeks. This may not sound like much to you there on your bejewelled rock, but you always know there is another within reach, even on the sea or up a mountain. You can feel them in your mind, even if you don’t know it. This affinity does not stretch to the stars. You are alone. You can try to compensate with a radio link, sending out tenuous and intangible ripples in the vacuum to your fellow men, hoping that they will be collected, concentrated, amplified, and replied to after the Empty God has imposed his time delay that can only get ever worse. But the radio is a false prophet against the endless night. It is not natural – the Empty God may reject such objects and send his subtle fury against it. And then you are alone again.

I tried to fix the radio myself, but I am a fission engineer – I have little knowledge of the electronics in the cabinet behind the primary computer. I can recognise the components, I even can make out a few system blocks. This must be an amplification stage, but which? Is this the data buffer – but what format is it? I gave up after a week. I tried to use the low-gain antennae and the simpler emergency radio, but they were also too damaged. I did manage to get a crude receiver working, remembering my Elem. Phys. Lessons from primary school. I could just make out the screeching hiss of the data signal behind the surging ocean of static from the Sun, which would drown it out for hours on end and provide tantalising moments of clarity. I lay for days fiddling with it, trying to get a clear signal. Anything would do now, even a whisper of a commercial radio show, despite the fact that I was thousands of times further from them than the most remote farmstead. Anything that could hold back the icily cold grip of the Empty God around my heart. This was not supposed to happen. The chances against this failure are astronomical. The delicate irony does not escape me as I gingerly line up the guide stars by hand, remaining gas thrusters hissing minutely as I add a second of arc here, take one from here and try to cancel the three-axis rotation of the Caelestis LXI, hoping that the ravaged thrusters do not repeat what caused this. The guidance computer is still operational, but has limited control of the thrusters. It takes me a full day of gently nudging the craft to point her axis down the line to the Minerva Station, still hundreds of millions of miles away. After days of gradual adjustment, the axial rotation is slowed to a sedate rotation per seven minutes, enough so that objects float gradually to the outside of my cylinder, clearing my working space.

I still don't fully know what happened. We were preparing for our halfway “flip”, to point the ion thrusters in our direction travel to rob us of a full half of our speed before we arrived in the Earth-Moon system, where we were supposed to perform an elaborate gravity-brake before entering the Far Side Gauntlet where great magnetic fields would slow us down enough to shed our cargo, berth at Selene Station and then return to Troy or Jovia L4. Just as we were running our final checks, I was preparing the reactor for the not-so-taxing turn. All we had to do was fire the forward ventral thrusters and the rear dorsal thrusters phased to rotate the craft around her midpoint, while still spinning. The aim was a kind of rotating backflip – you see divers doing it all the time just before they slide into the blue water. In fact, we saw them do it in the 2112 Xijing Olympics, beamed to us just one week before T-Zero, as I like to call the start of my problem. Melodramatic and egocentric maybe, but it’s clear to me that it is a defining point in my life, or what if left of it. They were beautiful Olympics, I must say. After the fiasco in 2012, famous for its failure even now, it took exactly a century for the Games to return to Xijing. The stadium in the old region of Chensingden, near the People's Technical University and the Park of the Newly Departed, was glorious. The Sea of Light it was called. The Olympic Flame burned long and bright against the clear skies above the Blue River, Lan He, twisting and turning through the ancient city, which relinquished it's name to the modern world, but renewed its dignity. My father, who has lived there for 80 years, refuses to call it Xijing, the name symbolising the bright future of humanity together rather than apart – shrouded in historical darkness as it is, he prefers “London”.

The sequence of thruster firings was tried and tested. There have been sixty missions like this before; as far as I can tell, the last twenty-seven have used the same manoeuvre, fourteen have used this very vessel. But this time it went wrong. The thrusters sequence was initialised by the guidance computer and the chorus of susurrations permeated the ship, shifting as the thrusters phased around the rotation of our little oasis of light, air and warmth. It’s dark and cold out here now. I wish I was at home. I wish I had never left my Meiying for this life. I thought the stars could offer me more. I thought I could find myself up here, in the realm of abstractions. I was wrong. Here, in the boundless void, you can only lose yourself. You will slowly leak away in the darkness, your soul bubbling away like water in the vacuum. Without others to provide pressure to hold it in, it floats away, ethereal, sublime. You cannot regain it. You belong to the Empty God now.

One minute, seven seconds and five hundred and sixty-two milliseconds after the thrusters started there was a crackle running along the spine of the ship. 01:07.562. I cannot forget this number. It is etched on my visual cortex after so long staring at the logs of the incident. The guidance computer instantly shut down the thrusters, but it was too late. The first left dorsal distribution line to the thrusters had ruptured, spraying an entire tank of the propellant gas into the cavity between the pressurized crew capsule and the secondary micrometeoroid plating. The sudden pressure differential blew off at least six panels of the plating and imparted a slight oblique spin to our craft. Normally, this rupture would result in the loss of, at most, 200 millilitres of gas: insignificant. But none of the six flow rate sensors in the gas regulator tripped, the secondary valve was stuck open and the tank was not closed off as it should have been. It was a compound error of a type only seen in the most ridiculous of the far-fetched simulations of the People's Space Agency.

I have since been out there and inspected the damage that started this. I removed and brought all the defective components inside to examine them. This was nothing too arduous; we had been done the same for the First Left Ventral system only days before T-Zero (minus the hole in the plating, obviously). We just hadn’t yet done the First Left Dorsal line. It was even down for the next week – the schedule reads “Inspect and Repair FLD Propellant Distribution System”. You may ask why this wasn’t down to be done before the flip, and that is a good question, but life in space is busy when each system you rely on every second to keep your delicate human functions continuing is so complex. Besides, this incident was not too serious. We just had a slight spin and drift from the ejection of the gas and plating to correct. The craft can function with only a few thrusters, there are more than three times as many as we need. The components were merely badly made – they should never have passed quality control at whichever factory they were made. Alan Shepard was right all those years ago, before the new millennium ushered in its changes. "It's a very sobering feeling to be up in space and realise that one's safety factor was determined by the lowest bidder on a government contract." Damnable Americans, flooding the market with cheap tat. They should stick to making plastic toys and garden furniture. Leave the real manufacturing to those who know how to do it. One day, this way of doing things will be eliminated, the world will turn on the axis of adventure and glory, of exploration and curiosity. No longer will people make things cheaply to make a profit – the will make them the best they can, because they can. People will want to help their species blossom into star-farers; we will join together and defeat the Empty God; people and The People combined into a new force. Until then, my dear Meiying, we will suffer the inequities of the materialists and deal with the consequences.

We told ourselves that compared to a disaster like a Reactor Containment Breach and Radioisotope Habitat Incursion, as a certain prolonged agonising death at the cellular level is so coldly put, we have no problem. We were slowly but efficiently working to put the Caelestis back on course, to line up the axis of the craft with our trajectory, putting the body of the craft behind the engines and debris shield. We spent two hours analysing the spin of the craft, checking and double checking the calculations. It was not necessary to be so sure, but it can never usually hurt. Usually. We were almost ready to set ourselves straight when the Empty God struck his hammer blow to our little home. I was rechecking the reactor's systems from the primary reactor control unit in the rear compartment, when the ship rang like a bell. There was a sudden and terrible roar that started in an instant and only increased from there, and the air leapt forwards through the hatch way to the front of the crew habitat. The emergency section seals came down like guillotines, sealing the ship into segments. I was now trapped in the rearmost section, alarms ringing to confirm what did not need confirming.

I still remember the sight that greeted me when I had managed to release the seals that were not holding back a pressure differential, put my pressure suit on and entered the depressurised compartment. There is not a human alive that could not help but have that sight imprinted on his consciousness forever. We had clearly been hit by a meteoroid – there was a pair of holes in the hull, each about twenty centimetres across, like an inanimate sniper victim. I surmised that the impactor had passed close to our navigator and electronic specialist, as she was horribly twisted, as if battered by a landslide and hung from an invisible line. The pressure wave and vacuum left behind as the projectile tore through the atmosphere must have been terrible. As for the pilot, I could only assume he must have been in the way, as there were only blood stains on the walls and a couple of larger pieces of meat that had not been sucked away into the void by the escaping air. I still see them, in my imagination and on the docking radar. I put the remains in the airlock and flushed them away into space. I did not say anything – I could think of no words to fit their fate, and I just wanted rid of the grotesque remnants of the two people who were previously my only companions. They drifted away at a leisurely pace – I estimate it will be another five days before they are out of range of the radar. Then I will have only memories, not even a ghost on the guidance computer’s display.

If we had only performed the corrections sooner, it would have missed us. If only we had repaired the system ahead of schedule, we would have been behind our shield. If only we had left Earth one second later, the meteoroid would have missed us by miles. If only we had never left Earth, I would be sitting at home, I would never have left you. I’m sorry. I know you will not get this for months, but I want you to know I know I was wrong.

The power is failing now. On my first EVA after T-Zero, I counted seven holes in the ship, so we must have been hit by some sort of meteor cluster. I have never heard of such a thing. One has all but removed the high gain antenna and most of the multiply redundant but conjoined radio equipment, explaining my lack of ability to hear anything but sighs and whistles carried on the gentle breeze of the vacuum. Most have taken out minor systems and the backups could handle it. But two have hit the reactor. They have not breached the inner containment vessel, but there is a leak in the pipes carrying the vital coolant to the reactor’s core and the control rods have been mostly shot away or buckled. The coolant is leaking away, drop by drop, and there is nothing I can do to stop the furious fisson processes still burning. There are several independent coolant circuits, but I cannot find one where the pressure doesn’t creep down. I have already tapped into the reserve coolant reservoir of the Emergency Core Cooling System; if I hadn’t I would be dead already. But it will only last me a week more, ten days at most. After that, my air will dwindle, my lights will dim and splutter and I will freeze. Or I would, if I wasn’t crawling out here like an insect on a child’s model. You, see, when the coolant fails, the reactor will overheat, the core will melt and the plutonium will slowly melt its way through the walls of the ship’s heart. If that happens, a constellation of molten plutonium droplets will enter the Earth-Moon system. Maybe it will be spotted and stopped by the Inner System Transients Board, but maybe not. I cannot allow that.

You probably know that radiation is not that dangerous, in moderation. You measure it in the number of dental x-rays you have, the hours you spend on intercontinental plane journeys. But this is different. A Caelestis class interplanetary tug weighs almost half a million tonnes. The design is old, nearly half a century, but the reactor, though apparently vulnerable to meteor strikes, contains almost four tonnes of highly radioactive fuel, spent and unspent. This, when distributed into a cloud, as it will be if the reactor is breached and it escapes on a gush of coolant vapour, could irradiate a massive swathe of lunar soil, contaminate the Earth’s atmosphere for decades or just lie in Earth-Moon orbit, causing untold damage to the stations and traffic there. After all, besides being able to undo your cellular structure atom at a time, the droplets are heavy metal and are not far removed from armour piercing rounds. They could easily pass through a space station, especially if they come from an unexpected trajectory.

A Caelestis class tug looks like a stretched out stack of eight discs connected by a central shaft. Between the discs, the cargo containers are arranged, stacked outwards from the shaft. The front disc is slightly conical, is made of steel and spun diamond fibre. It would have stopped the meteors dead if we had been facing forward. The back disc is the same, but the ion engines protrude through it and project our momentum away in a faint haze of blue light. The reactor is behind the engines and is shielded from the rest of the ship by a steel and lunar concrete divider. In this way, less shielding is needed for the sides of the reactor – the radiation escapes into space to join the solar wind. However, every ship repairman and tug runner knows never to go near the rear section of a Caelestis. There are remote dockyard drones for that explicit purpose. The idea that I am maybe the first person in over forty years to venture over the barrier and approach Big Red, as I have come to know this lump of deadly metal and concrete, doesn’t comfort me as I secure one safety strap of my harness to the outermost aluminium rung on the front of the concrete disc. The gravity and perspective here play games with the mind, even of an experienced astronaut. If you let go here, the rotation of the ship will fling you off like a child from a roundabout. However, rather than a grazed knee, you will experience the icy cold, glacially slow embrace of the Empty God.

I carefully clip the harness to the first rung on the outer edge of the shield and check it is fast before undoing the first one and placing it one the next rung. I am now hanging from my fingers, dangling over the formless void. Stars wheel under my feet, and I fight the urge to vomit. If I do that, I could die here, pointlessly, hanging from my ship, suffocated by the last thing I ate. I cannot do that – I must submit to the worse fate ahead of me. My load is difficult to manoeuvre around the corner, its metallic bulk trying to peel me off and throw me to the stars. I curse the designers of the ship for not putting a door near the shield's centre for such fatal adventures. Didn’t they know I would be doing this?

The Caelestis LXI was carrying, amongst other things, a cargo of geological samples and metals from the Troy mining station to Earth for evaluation of industrial potential of the asteroids trapped at the fourth Lagrange point of Jupiter. This station is equipped for minor purification to reduce shipping weight, and has produced, amongst hundreds of other materials, ingots of zirconium. Zirconium is a common material in reactors like this one as it does not stop the neutrons that cause the fission and produce the immense power that drives the vessel. However, the zirconium ingots from Troy are not pure and contain an unusually high level of the rarer hafnium, which is a superb neutron poison – it absorbs the neutrons in the core and halts the reaction. It lasts a long time in the core too – as the neutrons pound away at its structure, it decays through a sequence of five elements, all of which will prevent Big Red from blowing himself apart in a blaze of subatomic fury.

I have spent five days working on the zirconium, hacking away at the long ingots in the cargo containers in the front section of the ship with what tools I have to hand. I have used half of my fuel for the cutting lance and I daren’t use more in case I need it later. I then have to haul the chucks of metal up to the spindle where their mass only manifests as a disdain for motion, rather than the active burden it causes near the rim of the ship. I float the pieces down the central corridor, through five other sections of the ship. Of course, the zirconium had to be at the far end of the ship, didn’t it? However I keep my mind focussed on the work ahead of me, my thoughts always drift back to what I am about to do. The entire sum of my life, every little experience, each minute slice of being seems the press against me from behind, forcing me onwards, a horribly finite integral of existence.

I've moved over a tonne of metal to the reactor, and I am now over the bioshield and committed to the plan. Even if I pull out of this stupid idea, I will die from radiation poisoning within days, just in time for me to be unable to tell which would kill me first, cold or cell death. The outer shell of the reactor does not yield easily to the cutting lance, and it is hours before I have cut away the ruined control rods and broken actuators, retaining the few remaining fragments of control rod to help me kill the decay continuing inside the shattered reactor. As I peel back the last layers of containment structure, I can feel the radiation billow out past me into space, ionising the air in my suit, tingling, burning. I know I don’t have long now. At most an hour, probably less. I am already feeling weak, and my vision is beginning to blur. I begin to slide the rough pieces of control rod and zirconium into the black eyes of Big Red. I think I can see the end of the control rod cavities glowing faintly with heat, but I can no longer tell if that is true, or if it is my eyes. There are eighteen control rod cavities to fill. I work steadily, trying not to exhaust myself in the onslaught of the invisible particles and photons streaming away from the crippled reactor, the ethereal blood of the dying beast. I hope this works.

I have used all the neutron poisons up now – fourteen cavities have been filled. I am lying on my back against the spindle in front of the reactor, up against the coolant system. The stars continue their dance around me, but I can only just make them out through the clouded faceplate of my suit. My corneas have misted up too, the light of my head-up display is diffuse now, your face just visible through the haze. It’s amazing the thing still works after this. I remember when we took the photo I am trying to look at – we were so happy. Your graduation from the People’s Technical University of Xijing, your face suffused with joy, standing on the lawn in front of the great square tower, holding the rolled document close to your heart. I wonder what you would have said if I had told you it would be the last thing I would ever see.

I can’t talk much longer, Meiying. My lips and face continue to swell, I feel like my suit is full of molten steel, and my mind is drifting away. I can’t hold my head up any more: I am lying on my back, looking along the side of the reactor. The hole where the impactor that struck the coolant system hit is about half a metre from my face, I can make out the black aperture in the pure white casing. Odd, now I’m here in person, it looks blackened and burnt at the edge. It should be a clean hole. Maybe it’s just me. I can’t see much now. At least I chose my fate. The Empty God shall not claim this soul.

I don't care about this ship anymore. If it wants, it will look after itself. I just want you now. I’m sorry. God, it hurts. I can’t hold out.

Please. Meiying. Be here. With me. Now. Forgive me. Help me. I’m sorry. Meiying. I love…