Marchenko saw himself lying in the crevasse, his right arm unnaturally twisted, with large cracks in the visor of his helmet. A film of ice must have protected him from the vacuum—this was the only explanation he could come up with. The image that had suddenly popped up in his memory did not belong there. He shook his head vigorously. What he just remembered must have been a dream—it could only be a dream, a creation of his own imagination. He obviously must have been asleep earlier.
Then again, he was not sure. He tried to suppress the big question, but in vain. Didn’t he have anything more important to do than to wonder why he had survived the crash into the ice? The answer to this would be useless if he could not solve a much more important problem: generating enough energy in order to survive beyond the next 48 hours—40 hours, he corrected himself after a glance at his display.
If only he had paid more attention in physics classes! Hayato or Martin would have probably found a solution by now. Actually, he knew enough physics to realize he was in a favorable situation as far as energy was concerned, since the conditions here were so extreme. In order to tap into energy one needed disparities, differences, extreme values, a gradient, and there was plenty of it on Enceladus. Coldness here, vacuum there, darkness there, and the geysers even provided movement. How could he derive energy from it? He really was not much of an engineer. To simply turn a crank was not enough. As a doctor, Marchenko knew how much mechanical work a human could generate, significantly less than one horsepower, or HP. This did not help him at all.
He sat down at the console. While he had no online connection to the ship’s archives, he might be lucky enough to find enough data stored here. What he would find depended to a degree on what Martin and Francesca had last been doing. He was not accustomed to typing with his left hand, but he quickly got used to it. Marchenko scrolled through the files and entered various search terms: energy, cold, heat, pressure. The computer chips, he found out, were being cooled by Peltier elements that could convert heat into electricity. However, they would not provide sufficient power, at least not with the small number of elements he could take from the on-board computers.
When he searched for the term ‘cold’ he found the scan of an old book Martin must have uploaded at some point. It was by a certain Hanns Günther, and its title was In a Century—The Future Energy Supply of the World. The original text was in German, but the computer had already automatically created an English translation. The short book was 115 years old and it seemed to date from a time when people still had full confidence in technology. Back then, the author was worried a coal shortage might wipe out civilization. He therefore suggested alternative sources of energy, among them the idea of blocking the Straits of Gibraltar with a giant dam and lowering the sea level of the Mediterranean by 200 meters in order to generate energy from this height differential. Marchenko scrolled through to a chapter describing a power station suitable for the cold regions of Earth—the Barjot polar power plant.
The principle was simple, conceptualized around the start of the 20th century. Liquid water, which always had a temperature around zero degrees at the poles, was pumped up from the ocean. Its heat made a working fluid evaporate that must be liquid under the outside temperature (Barjot assumed minus 22 degrees). The steam powered a generator. Marchenko nodded. What did he need? He felt he was on the right track. A pump was no problem. The jets of Valkyrie were perfectly suitable—and they could also be used as generators. The drill vehicle had several jets that could be controlled independently of each other. There was water below, a whole ocean of it. There were enough cold temperatures at the surface. Next, he wondered about the working fluid. He checked the on-board supplies. There were several tanks of ammonia because the cooling system used it. Ammonia would be very suitable. In order not to be poisoned, he would have to provide good insulation for the system in which the gas evaporated, as well as for the generator. He also would have to manage to keep the ammonia in liquid form, since it froze below minus 78 degrees.
Marchenko leaned back. It looked like a 150-year-old idea might save his ass. He laughed out loud. “How fitting, Mitya.”
“Tshyort vasmi! Damn it!” Marchenko was cursing now. He had been studying texts about electronics for three hours. It was amazing what was stored on this computer. Now he learned he needed not only physics but also chemistry. Turning the concept of the Barjot polar power plant into reality here on Enceladus turned out to be much more complicated than he had assumed. He was a doctor, damn it, not some fucking scientist! Nevertheless, he wrestled with terms like ‘enthalpy of vaporization’ and ‘critical pressure.’ The problem was that he was not dealing with 0 and minus 22 degrees, but with a much larger temperature range. This meant he would have to adapt Barjot’s idea to these circumstances. He called up the phase diagram for ammonia, which showed him the usable range. The chemical was used in the cooling system of Valkyrie, which is why the vehicle had a certain supply of it. Ammonia, NH3, melts at minus 78 degrees and evaporates at minus 33 degrees. However, these temperatures changed as soon as a certain amount of water was involved, which he probably could not avoid. And pressure also played an important role. Methane would have probably been more suitable. He himself produced a bit of it every day in his digestive system, but it would not have been enough for running a power plant.
Otherwise, the good news was that Valkyrie provided optimal circumstances. The jets could measure the temperature of material flowing through them at several points. He could also readjust things. If it got too warm, he would extract less water for heating, and if was too cold, the pump had to send more heating water from the ocean through the system. Marchenko grumbled. Who would have thought he would ever use ice-cold water for heating? In the technical articles, he read that ammonia was not only poisonous, but also explosive in a certain concentration. He absolutely must avoid contaminating his precious breathable air with the stuff. There was a critical moment, though—he would have to connect the coolant supply tank with his improvised power plant. The tank had a valve, but the pipe diameters did not match. He would have to construct an adapter pipe and slide it on like a condom. He was not afraid of the challenge. After all, Russian cosmonauts were well known for their talent for improvisation. Yet he also knew such jury-rigged solutions were never 100 percent perfect. He would be happy if it reached 99 percent, though this meant a certain amount of ammonia would escape. The lethal dose, his articles said, was well above the tolerable one. Marchenko briefly wondered whether this should make him happy or skeptical.
It did not matter. He needed to start now because there were only 24 hours remaining. He used the control system to reconfigure the drives so they could work as a pump or generator. He needed a primary system to suck water out of the ocean below him, and a secondary system, the ammonia circuit. The water, which at zero degrees was relatively warm, would cause the ammonia in the secondary system to evaporate, then power the generator and refreeze. Since he had plenty of water available, the primary system could be open. The secondary system, though, had to be closed. He could not replace the ammonia that was circulating through it.
The jets alone would not be enough. He would also need something that would let the ammonia circulate. In the archive he found a repair manual for Valkyrie. Between the jets at the front and those at the rear there was a duct, a flexible pipe with a diameter of about 25 centimeters. It served to equalize pressure differences in the ice created by the heated water during the drilling. He needed this pipe for his secondary circuit. Marchenko glanced down at his body. At that moment he would have liked to have been a bit shorter and more agile, because the diagrams showed him how tight things were inside Valkyrie. Half an hour ago he had given himself a shot of painkiller so his right arm would not act up.
Valkyrie had a maintenance access at the bow, and he barely managed to squeeze through it. He crawled on all fours. The duct smelled of dust, dirt, and metal. His flashlight picked out various devices, the functions of which he had already
forgotten. He was only interested in the pipe itself. According to the manual, the pressure equalization function started automatically if the pressure at the two ends differed. Without this pipe, Valkyrie would no longer be able to drill through the ice layers. Marchenko pitied Valkyrie—it felt as if he was taking part of its identity, like a doctor amputating a person’s leg. All the while, using his left hand, he loosened four bolts to pull the pipe from the opening.
Then it was time for the rear end. He crawled backward for a bit until he found enough space to turn around. In doing so, his right hand unexpectedly touched something soft. Marchenko quickly aimed his flashlight at it—it was a small, dead rat. He could not suppress a shudder. The animal must have managed to come aboard on Earth, maybe during one of the transports of the drill vehicle. Unlike the lander, Valkyrie did not go from a clean room directly into space, but had completed several prior missions on Earth. He wondered how the rat must have felt in zero gravity. It may have even starved to death before launch, he concluded.
Half an hour later he had removed the pipe at the rear end. Marchenko crawled back to the access panel and squeezed through it. His overall was dirty and covered with dust. The fresh air up here made him sneeze, but he felt fine. Everything was working according to plan. He slowly pulled out the pipe, hoping it would not get caught anywhere. He was in luck. Ha!
He sat down and looked at his watch: another 22 hours. It was definitely too early to take a break. Now he needed to go outside and install the pipe as the secondary circuit. First he wrapped it with anything he could find, hoping to keep the cold out.
He really did not want to step back into his stinking spacesuit, but he had no other choice. Then he remembered he could not go outside because the helmet’s visor was defective. “Tshyort vasmi.” His curse was not nearly as loud this time. Marchenko felt himself growing weaker. How was he supposed to fix the visor?
Slowly, Mitya. You can do it. It wasn’t so dramatic. The difference between normal pressure and zero pressure was minimal. He should be able to repair it with a piece of stiff polypropylene, the transparent material used for document protectors. He only needed a really good adhesive to avoid any leakage. The adhesive was two-component glue, an essential part of an astronaut’s basic emergency kit. Marchenko did not have to search long for the material he needed to repair the visor. It was right in front of him, covering the Valkyrie repair manual. He placed it on the helmet and cut out enough to leave a centimeter protruding on each side. The result was not pretty, but it would serve its purpose. He hoped! He put on the helmet and noticed that his nose touched the visor. Unlike the original material it did not curve much, but it should not be a problem.
Now he needed a thinner hose to get the water here and found something useful in the wastewater recycling system. This meant he would not be able to recycle his urine into drinking water in the future. Yes, there was plenty of water available, though it had to be filtered. And if he left Valkyrie now, he would lose part of his oxygen supply again. This aspect would not be so bad, for as soon as he had electricity again he could generate breathable air. He divided the narrow hose into two parts.
Then Marchenko got up and started to put on the spacesuit. Lower part, upper part, at least the right arm did not complain. Before putting on the helmet Marchenko held his breath for a moment. There was a strong, lingering smell, and the whole suit was still wet with his now-cold perspiration. Once he got moving, the moisture was going to warm up, though. He opened the emergency exit and took a little leap upward—the low gravity also had its advantages. “YEE-HAAA!” he yelled, feeling happy and relieved things were working well. The improvised visor held firm, although it lacked the glass coating. Without the coating, the water vapor from his breath condensed on his visor and ran down in drops, yet Marchenko could still see well enough to safely move about.
The area around Valkyrie was frozen, but this posed no problem. He used his helmet radio and ordered the computer to melt the ice with the jets. Marchenko watched the surface grow darker, and a bubbling hole developed. Marchenko commanded the computer to stop. Now he would go for a swim.
He eased himself down into the hole and immediately felt the intense cold. The water drained the heat much faster from his suit than did the vacuum on the surface, even though the water was considerably warmer. The heater turned itself on and successfully fought against the cold. His nose was the only part of him that was not doing well. Its tip firmly pressed against the makeshift visor and quickly became so cold that it hurt.
Marchenko did not have the time to deal with this issue. He looked for the two jets he needed to reconfigure. He placed the thick but flexible pipe in the shape of an ellipse around the jet that later would become the generator. It rose above the surface of the water and would soon freeze in place there. Then he would just have to fill ammonia into the circuit from the inside. He connected the thinner hose with the input and output of the other jet. As a pump it would pull water from the depths and use it to heat the primary circuit. Marchenko was curious what degree of efficiency he would achieve. Of course the pump also consumed energy. If the generator in turn provided a bit more energy, he would be saved.
He looked around. The water was dark. The headlamp of his helmet created a cone of light. The water appeared thicker than usual, like a gel. He even thought he could notice movement inside the water. He turned off the headlamp.
There was a deep and pervasive darkness surrounding him. When he closed his eyes it instead became brighter, not darker. The humming of the life-support system sounded so calming that he was not afraid. Did a child in the womb feel like this? Then small lights came on in the distance. Marchenko was amazed. Was it cosmic radiation hitting his retina? He closed his eyes and the lights disappeared. They were obviously part of reality. He swam forward until he hit the bare ice.
He could not go any farther. The lights were somewhere ahead in the distance, or at least it looked that way. They shined evenly, and this made them look artificial, which was impossible. Marchenko was glad he was no physicist. If he was one, he would be searching for reasonable explanations now. This way he could just simply marvel at it. The lights in front of his eyes began to change. They disappeared and reappeared, creating patterns resembling artful, elaborate script. He forgot about time, until all the lights finally faded away.
His arm display told him 15 minutes had passed, and he switched on his helmet lamp again. He had to test to see if the power plant was providing energy. Strangely enough, he felt this was not so important anymore after watching the light show, but he pulled himself together. Marchenko hurried into Valkyrie and out of his spacesuit. The tip of his nose was burning, but he decided to ignore the pain.
First of all, he had to divert the ammonia into the primary circuit. He prepared the adapter pipe, attached it, and then had to briefly open the valve. A small puff of gas drifted out, and the acrid smell almost made him vomit, but he managed to avoid it. The small amount of gas would distribute itself throughout the room and be rendered harmless by the life-support system.
He went to the control console and first changed the settings so that initially a small amount of water warmed the primary circuit. The pump started to work, and it only took a few seconds before the generator indicated it was indeed producing electricity. Marchenko slowly increased water flow to boost the performance of the pump. The temperatures remained in the correct range. The performance of the ‘power plant’ increased. After ten minutes he thought he had reached the point of maximum potential. He checked to verify his assumption and found out he was right—any more water per second led to a lower energy output.
Now, the two key questions: how much energy was he putting into the system, and how much was coming out of it? He performed a rough calculation and came up with a conversion efficiency of six percent. This meant that for each kilowatt-hour the pump consumed, the generator provided 1.06 kilowatt-hours by taking energy from the warm water via ammonia evaporation. This was not the
only important value, however. How much energy per hour could the system generate, and when would Valkyrie’s batteries be fully charged? Since he did not know where ILSE was located he could not use a direct message, but rather he had to send an interplanetary broadcast. For this purpose, he must have Valkyrie at full battery capacity.
Marchenko typed in the numbers. One press of a button and the result appeared: in about two days, he would be able to transmit his message into space.
December 29, 2046, ILSE
Francesca stood up straight and stretched. She had forgotten how straining it was to maintain the stooping posture required during gardening. Their garden module, the Closed Ecological Life Support System, or CELSS, had been stabilized and would provide fresh food again during the return journey. There were sufficient supplies of food available, but fresh lettuce and home-grown potatoes would improve the crew’s morale. The light in the module flickered, and then Watson spoke.
“Important transmission from Earth.”
Watson could have left out the word ‘important,’ Francesca thought. They were not supposed to be bothered with insignificant messages during their work shifts. She wiped the sweat off her face with the sleeve of her overall. Such clothing was required now that part of this module had become the baby's play area. It was hot and stuffy inside CELSS because a high CO2 content helped the plants to grow successfully, so they had previously agreed to work alone and in their underwear.
The Titan Probe Page 6