I unfastened the drain cock on the fuel tank cautiously I thought maybe I might be in trouble. Many liquids boil at such low pressures, and I did not want to be scalded by a freezing jet of alcohol steam.
It was all right. In the deep cold of the shade of the rocket's interior, I merely ran off a little liquid which rapidly evaporated, surrounding me with heady, heavy fumes which I could smell through my mask as I drew in outer air mixed with oxygen. On Earth, I would have been afraid of fire. On Mars, I merely shut the tap again and thought.
I looked around the engine-room. The one thing I had was a superfluity of pipes and pumps. There was a six-inch fuel pump connected to that very tank, which had been used to deliver the mixture to the firing chambers. There was an oxygen pump, which, if used for its intended purpose, would deplete my supply of air in almost no time at all. There was a one-inch water pump connected to the domestic supply line, and a larger pump which had taken water to the motors, both connected to the cracked and empty tank There were pumps connected to the hydraulic machinery. The only thing I had more of than pumps was electric motors, and all were useless unless I intended to waste my substance on them.
Useless, that was, connected as they were.
I set to work. The first thing to do was to find two positions, one which would be in sunlight all the day and the other which would be in shade. When I had found these, I began to disconnect lengths of piping. It was slow, tedious work, disconnecting joints and elbows and remaking them. I had to make a grid of parallel pipes in the sunlight and another grid in the shade. Not all the joints and sections were intended for my purpose, and I had to improvise. But it was reassuring to discover, at the end of the morning, that in the hot pipes in the sun my petroleum vaporised at once, and that in the cold pipes in the shade it condensed again and became a liquid.
I worked on through the afternoon. I could see that the result was going to be very crude. I used a one-inch pump to pump the fuel liquid into the heating pipes. A six-inch pump was all I could find, the largest that is to say, for the boiling petroleum to drive. I hoped my memories of water-tube boilers on Earth was adequate. I stood back and looked at my work from time to time.
It happened even before I finished. I had run a quantity of fuel into the cold pipes, which were used as the condenser, and turned the small pump by hand to force some of the liquid into the hot pipes. The big pump, driven not by steam but by boiling petroleum, made one stroke, then another. Before I knew what was happening, she was running merrily away. I had to wait until the charge was exhausted before I could connect the two pumps.
The sun was sinking. I had not expected my heat engine to work at that time of day, though I had gone to the extent of burying the cold pipes in frosty earth which had had no sunlight on it. I had thought: perhaps in the mornings only, when the temperature difference was greatest. But I had forgotten that though the pressures I was dealing with were very small, so was gravity, and therefore friction, on Mars.
I stood back and watched the wheels go round. I doubt if anyone ever had the same sense of creation as I had then. I drew no power from the machine. I simply watched it. I had done that. Petroleum was being pumped into the hot pipes where it boiled in the sun's heat. The vapour developed pressure enough to drive the big pump. The big pump drove the small one. The vapour, after passing through the big pump, went through the condenser and returned as liquid to be pumped again by the small pump. The same petroleum went round and round, again and again, like the water in a marine steam engine. It was not burned or used at all, except for losses due to leaks. The power source was the sunlight and a temperature difference of only sixty degrees Fahrenheit.
Heat engines were more efficient on Mars than on Earth just because the atmosphere was so thin: because the heat which came from the sunlight was not distributed equally over the surface of the planet by that vast reservoir of heat which was the treacly atmosphere of Earth.
Begrimed, my hand trembling as it held the spanner, I watched those two pumps working, the one driving the other. I was the happiest man in the entire universe at that moment. Wheels were going round. I had a source of motive power. Already, even with my machine in its first, crude state, the electric motors, which I had left connected to the pumps, were acting as generators and showing a voltage on my meter.
Power.
Power in a form more flexible and more usable than fire. Beautiful power. With that, it seemed to me, I could do anything.
The sun slowly sank, and, as the shadows became long across the empty plain, each little hollow and curve of land becoming a pool of darkness, the machine came to rest, running more slowly and finally stopping. But I did not care. It had run and, when I went into the closed compartment of the rocket again that night, I felt confident enough to use my light freely, and to use the battery power to cook myself a meal. Late that night, I found myself sitting on my couch, with a blanket around me it was true, but sitting up, and looking with a kind of wonder at my own hand, my right hand, in which, quite causelessly, I held a spanner.
11
i MUST have stayed up late that night. There was, after all, no one to please but myself. I overslept the following morning. When I awoke, it was to the tune of two pumps hammering away wildly outside my compartments in the rocket. It might have been thought that, for a moment on waking, I would have imagined myself back on Earth, where machinery sounds were common. But I did not. I came to full consciousness on an instant, and knew what the sound was. I leapt and staggered from my couch, put on my mask and harness, and went out into the cool morning. I connected the electric motors on the pumps in series, and tore out wiring from the damaged portion of the rocket to connect them to the battery. I stood in the early sunlight and looked at an ammeter which indicated a steady charge. Then I went back inside for breakfast.
It was a crude method of adjusting the voltage of two motors so that they charged the battery which had once driven them. But it worked for days, until I found time to make my machine more efficient. Then, my power needs having risen, I adjusted the brushes of the motors, took two cells out of the battery, and was able to draw off a good and heavy charge.
But such niceties were for the future. On that, my first power-driven morning, I was still too much aware that, though I had a source of heat and energy, I was a long way from converting electricity into water and air.
Always, until I had my engine going, I had thought of the solution of my problems in biological terms. I had thought that the only possibility of my survival lay in getting together a sufficient quantity of plants under airtight glass. Perhaps, in the long-term view, it did. But glass was something I was short of. All I had were still more pumps and electric motors, piping, burst tanks and sound ones, steel plates, and two beautiful but completely useless gyros.
With this material, I needed a simple and direct solution of my immediate problems.
Water was easy. I solved that problem in six hours flat. I had observed that at night, when the temperature dropped over the desert plain, the dew settled down and turned to frost. It was on this frost, when it melted in the morning, that the surface-rooted plants were living. What I wanted, obviously, was large quantities of dew. To get it, I needed to duplicate the conditions of a sudden drop of atmospheric pressure.
The burst water tank was the obvious choice. What took me most of my time was the job of repairing it. On the face of it, it was a simple welding job, with leads taken from the battery, but whoever had installed that tank in the rocket had not contemplated it being cracked and then re-welded while in situ. I had to do some sawing first, before I could get at the broken parts.
I used the old oxygen pump to draw out the air. The only difficulty at that stage was to get the right adjustment. The air had to be sucked out of the tank, when it was gas-tight once more, and, as a continuous process, fresh Martian atmosphere had to be allowed to whistle in slowly, undergoing a drop of pressure, and therefore of temperature, as it did so. The theory was that the de
w, formed as in a cloud-chamber, would condense on the walls of the tank and run down. But it is difficult to do this kind of thing when the total outside pressure is only a hundred millibars. First the oxygen pump, which had a far too powerful motor, tended to run away with me, and also to use too much power. _ Then, when I had fixed that by dismantling the thing and working on trial and error with the field coils, the jet to allow the air into the tank proved to be a matter of critical dimensions. I had to drill an assortment of plugs in the end, and try them one by one until, at the end of a quarter of an hour's pumping, I got a trace of water in the tank.
As I say, it took me six hours' steady work, which I later thought, when the thing was working, and water was accumulating visibly every time I opened up the manhole, was rather good. At the time, I remember, it seemed awkward and an unnecessarily laborious business.
The truth was that my mind was not wholly on the job. I was worrying about the far more difficult problem of getting oxygen. The only immediate source of it was the Martian air, and the best Earth estimates were that there was only one per cent of it in that I was getting down on equipment, too. I had only a few small pumps left, largely from the hydraulic system. The gyro motors were intact, but by no strength of imagination could I see any way of making a gyro motor produce air.
It had to be the pumps. I could only hope that the spectroscopic analysis of the Martian atmosphere, taken from Earth, would be to some extent misleading. There was a case for this. The Martian air, though very thin, was a singularly deep and tenuous layer compared with Earth's. The pressure on Earth decreased rapidly with altitude until, at the height of the summit of Everest, it was comparable to the pressure on the Martian surface. Thereafter it still continued to decrease at the same rate. But Mars, starting at that low pressure, had a less steep gradient. The air was thinner, above the surface, but not so much thinner as it would have been on Earth. The curves crossed. The upper air of Mars was comparatively plentiful and extended a long way out. And it was this distant, upper air which had been measured by telescope and spectrograph from Earth.
There was a reasonable probability that air at the surface, which I was now enriching with oxygen and breathing, actually contained more oxygen itself than the mere one per cent which had been forecast by astronomers. But the trouble was, I could not know, when the pressure was so low and the quantities were in any event so small, until I embarked on some sort of fractional analysis.
I began on it that day, and it worried me all night. I was still working on it the next day and the next.
I set up my machine inside the ship. I had to. I had to start with the coldest Martian air I could get. That meant drawing it in at night, and specifically in the pre-dawn hours, when temperatures near the surface dropped to nearly as low a figure as 200° on the Absolute scale, or about, in Fahrenheit notation, a hundred and fifty degrees of frost. I could not work in those temperatures. They had to be kept inside the apparatus I was building.
I got my first step down by drawing the night air through the water-condensation plant. I already had a drop of a good twenty degrees there. I was getting down.
A dozen times I cursed those little pumps from the hydraulic machinery, which was all I had to work with. It is a tough industrial process, to liquefy air and boil off its constituent gases at their respective temperatures. At least, it is if you have not the right equipment.
But if you have enough pumps you can't really go wrong. And I had enough pumps. They were small, they were not intended for the purpose, but they worked. They compressed gases, and that was what I needed.
From the water-condensation tank, the air was drawn in and compressed again. It was fed back through a coil of pipe in the tank, to lose the heat it had gained by its compression. Then it was fed out through a Jet into another chamber, becoming colder as it expanded..
I duplicated this refrigerating system, and continued to duplicate it. Each cooling-coil was set in the previous stage's expansion chamber. When I was reaching the end of my resources, I built a box round the whole contraption and filled it with heat-insulation in the form of teased-out blanket. Then I used feed-back, sending the same cold air round the circuit once again.
It was, after all, only the getting of the first, pure drop of liquefied Martian air that was really difficult. After that, I was able to use the unwanted, cold, and almost frozen fluids to cool the earlier stages.
I had five pipes in a row branching off a main pipe along which I maintained a steady, rising slope of temperature. The main pipe was broad, and it dipped and curled. Inside, a bubbling was in progress. No alchemist of ancient times ever approached the results of his experiments so cautiously as I, feeding those cold gases, in small proportions, into my mask.
It was just a fortnight after I landed that I was drinking Martian water and breathing Martian air made by power drawn from Martian sunlight.
That was what really began my troubles: when I realised the possibility of my survival and how much depended on the aggressiveness with which I attacked my problems.
12
FOOD WAS my overwhelming need. I had not thought it would be. The production of air and water in an airless desert had seemed to me so difficult of accomplishment, and so much a near-miracle when it was accomplished, that I had thought the production of food in a place where there was already life of a rudimentary sort to be almost a matter of course.
Was not the desert surrounding the wreck, despite the mean appearance given to it by its narrow, pinched horizons, and the cold and lack of air and water, actually flowering? It was true that the plants were widely scattered and, even supposing I could somehow eat them directly, I would have to range over a wide area to get my food. But they were life, and the human digestion is wonderfully adaptable when it comes to the absorption of living things, and with water —I was getting a little then, and I did not doubt that I would get more in future—I could surely make them grow profusely. Besides, as a last resort, I had the insects and their honey.
I attacked the problem of food with aU the energy and directness which I had discovered was necessary if I was to survive. I gave myself an hour's relaxation on the morning after I had solved my immediate air and water problems, and spent it looking at the dun-coloured plain as I emerged from the rocket and at the sky above it, which changed, at different times of day, from dark blue-black to bottle-green. It was a strange sky, which, because the stars were always visible in it except in an area closely around the sun, gave a false impression of nakedness and altitude, but I did not spend too long on it. I was soon doing what I had to do. I went to the nearest of the plants and began gently to ease its spreading, radiating fibres from the dusty earth.
That was where I struck my first difficulty. It was a simple mechanical one. I was down on my knees, examining the plant critically and in detail for the first time, and it only needed my sense of touch to tell me that the apparently fine and succulent red-green tendrils above ground were in fact of the toughness and consistency of leather. I went for the roots, on the assumption that there must be some soft part somewhere. But it would have been more easy to separate the fine filaments of a mushroom root on Earth from the mould in which it grew than to take up and clean the root of that plant. The filaments spread for yards, but, digging in the soil, it was hardly possible to detect them with the naked eye.
The plant came up without its roots, every spreading runner breaking off at the point at which it made contact with the ground.
I was left with perhaps half a pound of tough stems, like a vine on Earth, and with perhaps two ounces of what, because of their green colour, I thought of as the leaves. These, which just conceivably might be edible, were like fine stems of curling grass.
I went back into the wreck. I took my prize into the galley. I prepared a pan of boiling water and put the leaves into it. For a quarter of an hour I watched them boil. Then, very gingerly, I took out one stem and tried to eat it.
It was then that I realised that
I was showing more energy than thought. Those leaves were capable of withstanding the great temperature variations of the Martian day and night. And the water I was boiling was not, at that low pressure, at anything like the temperature of boiling water on the surface back on Earth. It was at a comparable, but lower temperature, than the hundred and seventy degrees at which water boiled in the tents of the upper camps of Everest and which had made it impossible for the climbers to brew their tea there. To try to eat that leaf was like trying to eat the toughest, uncooked, frond of grass.
I did not have a pressure cooker. I had to make one from a pan with a tight-fitting lid, which I carefully ground in until I got a perfect fitting on the flange, then loaded with weights until, by the way the steam hissed out, I detected that I had a distinct steam pressure inside. I left the plant to cook in that, at the same time thinking grimly that, if I were to have to use that amount of electric power for every meal, I would soon be back where I started, searching for new sources of energy.
In the meantime I went out of the rocket again, after setting the pan on low heat. It was afternoon by then, but I spent half an hour watching the insects. The singular aspects about them were their methodical distribution, so that I rarely had more than one in my field of view at once, and their habit of travelling in straight lines to and from their nest. They had never taken any notice of the wreck or endeavoured to avoid it or me. I had noticed when I was working on my machines that any obstacle I placed in their way caused them first to draw back, but only for an instant, and then to try to go on over it. If that was impossible— and they lacked both the energy and the adhesion of our quick-climbing species—then they went off at right-angles in a semi-circle, trying again and again with greater diameters of turn until they were able to complete a full semi-circle without deviation from what was evidently for them a geometric course, until they could resume then-straight-line path again.
Rex Gordon Page 6