I can no longer bear to read this story, now that Laika sleeps forever in the garden of the home we once shared.

When I heard Laika’s frantic barking, my first reaction was one of annoyance. I turned over in my bunk and murmured sleepily, ‘Shut up, you silly bitch.’ That dreamy interlude lasted only a fraction of a second; then consciousness returned – and, with it, fear. Fear of loneliness, and fear of madness.

For a moment I dared not open my eyes; I was afraid of what I might see. Reason told me that no dog had ever set foot upon this world, that Laika was separated from me by a quarter of a million miles of space – and, far more irrevocably, five years of time.

‘You’ve been dreaming,’ I told myself angrily. ‘Stop being a fool – open your eyes! You won’t see anything except the glow of the wall paint.’

That was right, of course. The tiny cabin was empty, the door tightly closed. I was alone with my memories, overwhelmed by the transcendental sadness that often comes when some bright dream fades into drab reality. The sense of loss was so desolating that I longed to return to sleep. It was well that I failed to do so, for at that moment sleep would have been death. But I did not know this for another five seconds, and during that eternity I was back on Earth, seeking what comfort I could from the past.

No one ever discovered Laika’s origin, though the Observatory staff made a few enquiries and I inserted several advertisements in the Pasadena newspapers. I found her, a lost and lonely ball of fluff, huddled by the roadside one summer evening when I was driving up to Palomar. Though I have never liked dogs, or indeed any animals, it was impossible to leave this helpless little creature to the mercy of the passing cars. With some qualms, wishing that I had a pair of gloves, I picked her up and dumped her in the baggage compartment. I was not going to hazard the upholstery of my new ’92 Vik, and felt that she could do little damage there. In this, I was not altogether correct.

When I had parked the car at the Monastery – the astronomers’ residential quarters, where I’d be living for the next week – I inspected my find without much enthusiasm. At that stage, I had intended to hand the puppy over to the janitor; but then it whimpered and opened its eyes. There was such an expression of helpless trust in them that – well, I changed my mind.

Sometimes I regretted that decision, though never for long. I had no idea how much trouble a growing dog could cause, deliberately and otherwise. My cleaning and repair bills soared; I could never be sure of finding an unravaged pair of socks or an unchewed copy of the Astrophysical Journal. But eventually Laika was both house-trained and Observatory-trained: she must have been the only dog ever to be allowed inside the two-hundred-inch dome. She would lie there quietly in the shadows for hours, while I was up in the cage making adjustments, quite content if she could hear my voice from time to time. The other astronomers became equally fond of her (it was old Dr Anderson who suggested her name), but from the beginning she was my dog, and would obey no one else. Not that she would always obey me.

She was a beautiful animal, about ninety-five per cent Alsatian. It was that missing five per cent, I imagine, that led to her being abandoned. (I still feel a surge of anger when I think of it, but since I shall never know the facts, I may be jumping to false conclusions.) Apart from two dark patches over the eyes, most of her body was a smoky grey, and her coat was soft as silk. When her ears were pricked up, she looked incredibly intelligent and alert; sometimes I would be discussing spectral types or stellar evolution with my colleague, and it would be hard to believe that she was not following the conversation.

Even now, I cannot understand why she became so attached to me, for I have made very few friends among human beings. Yet when I returned to the Observatory after an absence, she would go almost frantic with delight, bouncing around on her hind legs and putting her paws on my shoulders – which she could reach quite easily – all the while uttering small squeaks of joy which seemed highly inappropriate from so large a dog. I hated to leave her for more than a few days at a time, and though I could not take her with me on overseas trips, she accompanied me on most of my shorter journeys. She was with me when I drove north to attend that ill-fated seminar at Berkeley.

We were staying with university acquaintances; they had been polite about it, but obviously did not look forward to having a monster in the house. However, I assured them that Laika never gave the slightest trouble, and rather reluctantly they let her sleep in the living room. ‘You needn’t worry about burglars tonight,’ I said. ‘We don’t have any in Berkeley,’ they answered, rather coldly.

In the middle of the night, it seemed that they were wrong. I was awakened by a hysterical, high-pitched barking from Laika which I had heard only once before – when she had first seen a cow, and did not know what on earth to make of it. Cursing, I threw off the sheets and stumbled out into the darkness of the unfamiliar house. My main thought was to silence Laika before she roused my hosts – assuming that this was not already far too late. If there had been an intruder, he would certainly have taken flight by now. Indeed, I rather hoped that he had.

For a moment I stood beside the switch at the top of the stairs, wondering whether to throw it. Then I growled, ‘Shut up, Laika!’ and flooded the place with light.

She was scratching frantically at the door; pausing from time to time to give that hysterical yelp. ‘If you want out,’ I said angrily, ‘there’s no need for all that fuss.’ I went down, shot the bolt, and she took off into the night like a rocket.

It was very calm and still, with a waning Moon struggling to pierce the San Francisco fog. I stood in the luminous haze, looking out across the water to the lights of the city, waiting for Laika to come back so that I could chastise her suitably. I was still waiting when, for the second time in the twentieth century, the San Andreas Fault woke from its sleep.

Oddly enough, I was not frightened – at first. I can remember that two thoughts passed through my mind, in the moment before I realised the danger. Surely, I told myself, the geophysicists could have given us some warning. And then I found myself thinking, with great surprise, ‘I’d no idea that earthquakes make so much noise!’

It was about then that I knew that this was no ordinary quake; what happened afterward, I would prefer to forget. The Red Cross did not take me away until quite late the next morning, because I refused to leave Laika. As I looked at the shattered house containing the bodies of my friends, I knew that I owed my life to her; but the helicopter pilots could not be expected to understand that, and I cannot blame them for thinking that I was crazy, like so many of the others they had found wandering among the fires and the debris.

After that, I do not suppose we were ever apart for more than a few hours. I have been told – and I can well believe it – that I became less and less interested in human company, without being actively unsocial or misanthropic. Between them, the stars and Laika filled all my needs. We used to go for long walks together over the mountains; it was the happiest time I have ever known. There was only one flaw; I knew, though Laika could not, how soon it must end.

We had been planning the move for more than a decade. As far back as the nineteen-sixties it was realised that Earth was no place for an astronomical observatory. Even the small pilot instruments on the Moon had far outperformed all the telescopes peering through the murk and haze of the terrestrial atmosphere. The story of Mount Wilson, Palomar, Greenwich, and the other great names was coming to an end; they would still be used for training purposes, but the research frontier must move out into space.

I had to move with it; indeed, I had already been offered the post of Deputy Director, Farside Observatory. In a few months, I could hope to solve problems I had been working on for years. Beyond the atmosphere, I would be like a blind man who had suddenly been given sight.

It was utterly impossible, of course, to take Laika with me. The only animals on the Moon were those needed for experimental purposes; it might be another generation before pets were allowed, and even then it would cost a fortune to carry them there – and to keep them alive. Providing Laika with her usual two pounds of meat a day would, I calculated, take several times my quite comfortable salary.

The choice was simple and straightforward. I could stay on Earth and abandon my career. Or I could go to the Moon – and abandon Laika.

After all, she was only a dog. In a dozen years, she would be dead, while I should be reaching the peak of my profession. No sane man would have hesitated over the matter; yet I did hesitate, and if by now you do not understand why, no further words of mine can help.

In the end, I let matters go by default. Up to the very week I was due to leave, I had still made no plans for Laika. When Dr Anderson volunteered to look after her, I accepted numbly, with scarcely a word of thanks. The old physicist and his wife had always been fond of her, and I am afraid that they considered me indifferent and heartless – when the truth was just the opposite. We went for one more walk together over the hills; then I delivered her silently to the Andersons, and did not see her again.

Take-off was delayed almost twenty-four hours, until a major flare storm had cleared the Earth’s orbit; even so, the Van Allen belts were still so active that we had to make our exit through the North Polar Gap. It was a miserable flight; apart from the usual trouble with weightlessness, we were all groggy with antiradiation drugs. The ship was already over Farside before I took much interest in the proceedings, so I missed the sight of Earth dropping below the horizon. Nor was I really sorry; I wanted no reminders, and intended to think only of the future. Yet I could not shake off that feeling of guilt; I had deserted someone who loved and trusted me, and was no better than those who had abandoned Laika when she was a puppy, beside the dusty road to Palomar.

The news that she was dead reached me a month later. There was no reason that anyone knew; the Andersons had done their best, and were very upset. She had just lost interest in living, it seemed. For a while, I think I did the same; but work is a wonderful anodyne, and my programme was just getting under way. Though I never forgot Laika, in a little while the memory ceased to hurt.

Then why had it come back to haunt me, five years later, on the far side of the Moon? I was searching my mind for the reason when the metal building around me quivered as if under the impact of a heavy blow. I reacted without thinking, and was already closing the helmet of my emergency suit when the foundations slipped and the wall tore open with a short-lived scream of escaping air. Because I had automatically pressed the General Alarm button, we lost only two men, despite the fact that the tremor – the worst ever recorded on Farside – cracked all three of the Observatory’s pressure domes.

It is hardly necessary for me to say that I do not believe in the supernatural; everything that happened has a perfectly rational explanation, obvious to any man with the slightest knowledge of psychology. In the second San Francisco earthquake, Laika was not the only dog to sense approaching disaster; many such cases were reported. And on Farside, my own memories must have given me that heightened awareness, when my never-sleeping subconscious detected the first faint vibrations from within the Moon.

The human mind has strange and labyrinthine ways of going about its business; it knew the signal that would most swiftly rouse me to the knowledge of danger. There is nothing more to it than that; though in a sense one could say that Laika woke me on both occasions, there is no mystery about it, no miraculous warning across the gulf that neither man nor dog can ever bridge.

Of that I am sure, if I am sure of anything. Yet sometimes I wake now, in the silence of the Moon, and wish that the dream could have lasted a few seconds longer – so that I could have looked just once more into those luminous brown eyes, brimming with an unselfish, undemanding love I have found nowhere else on this or on any other world.