The Battle of Titan

by Sudipto Majumdar

  I think the levels were not connected to all the spirals, because this did not happen thankfully, although I instructed Lt. Ma to keep looking backwards every few seconds for an ambush from that direction. As we were crossing the third level, we got our first indication that the levels were not inter connected, and also a sign of our original pursuers.

  I heard the sound of their projectile weapon and was startled, not having heard it for some time and hoping to have lost the aliens with the guns. It hit the limb of an alien who was trying to slash me, and thus blocking me from the line of sight of the alien shooter. The original pursuers were on the opposite spiral ramp at the third level taking potshots at us from there!

  I realized what had happened. While the original pursuers were stalking us, these new aliens were hiding. They were probably civilians or technicians, not tasked to defend or fight. When we tripped whatever invisible switch we did, while approaching the ramp, these new aliens went berserk and tried to swamp us.

  Our original pursuers must have followed, but they had no clear shot at us behind these crazed aliens, so as trained soldiers they are doing the best they can. Get to high ground, and take a shot from there. Unfortunately for them, this is a spiral, so we keep turning away from them most of the time, when we did come into their sight, they took a shot which hit the lead alien on this ramp rather than me. I also noticed that their own bullets have a much more severe effect on them than ours. The hit alien staggered and slinked back as another alien took its place.

  I immediately shouted at Ma and Lao warning them of the snipers. I need not have warned them, they had noticed and were crouching to lower their profile. We decided to run backwards and surprise the attackers on our ramp, as well as the other ramp, whenever we start facing the snipers. Hopefully they will take some time to catch on to the pattern.

  We managed to reach to the topmost 15th level this way somehow. Lt. Ma warned us that we are reaching the top, and I asked Sgt. Lao to stop and stay with me, while I asked Lt. Ma to go and scout ahead for any sign of exhaust vent, or any other opening to the top.

  We didn’t want to reach the absolute top, and let these aliens have the ability to spread out and attack again. We had to confine them to the ramp. Besides it would also give the snipers a clear shot at us. We were currently hidden behind the ramp. I realized that Ma may not have considered the snipers, and shouted out to her to crawl out and be mindful of the snipers.

  With one less person to defend we had to work that much harder, and the aliens were being able reach us much closer. We were getting really tired and could not hold on much longer. Thankfully Lt. Ma came back fairly quickly with good news and bad news.

  The good news was that pillar around which this spiral ramp was built went all the way up to the ceiling. That was expected, after all it was a pillar supporting the ceiling. It had thick tubes running along it going up to the ceiling. The thick tubes were not only hot, but vibrating with the typical profile of exhaust fan running inside.

  The bad news was that this was not an air ventilation system. It seemed like a thermal exhaust. The pipes were heavily insulated. The pipes went into the ceiling completely sealed and air tight. There was no proverbial grill to break down and exit.

  To make matters worse, the ceiling was almost 10 meters above the level, and even if somehow we managed to break some part of the ceiling, there would be no way to climb up. Since there was no way to look out of the ceiling, we could not even say how far the surface was. The ceiling could be 10 meters thick for all we know.

  Damn! I thought to myself we are stuck in a dead end now. We were exhausted and would soon be overwhelmed. I was about to let myself spiral into despondency, when an old lesson from my days with the Engineering corps came to mind.

  Thermal exhausts meant that there was a heat exchanger. I could easily guess why they required a thermal exhaust in this chamber. Whatever they were cooking in this chamber, gave out a large amount of heat. They couldn’t however fix a large exhaust fan on the ceiling, and vent out the hot air.

  The atmosphere outside was dangerous even to the aliens, but more importantly they would lose all the precious oxygen in the chamber, which I was getting convinced the aliens need just like us to breathe. So they would use a heat exchanger, which is why there was a breeze blowing into this chamber.

  They would have strong fans inside the chamber blowing the warm air of the chamber over densely packed pipes. These pipes would be carrying some kind of coolant which is sealed and circulating with one end flowing outside pumping out the hot fluid, while the other end would take in cold fluid from the outside, thus completing the circuit and being able to dump waste heat outside without having to open themselves to the atmosphere.

  On earth if we made a similar system, we would use water from a nearby stream or lake. What would one use here on Titan? What is flowing as liquid on the surface? Why methane of course? We would take in water from a stream, heat it up with our waste heat and turn it to steam, which would then be vented from a chimney.

  This must be a similar system using methane. They pump in liquid methane below which would come in under pressure due to gravity, get heated and turn to gas and blow out of the chimney above at high pressure. They don’t even need to pump the circulation system. It would run efficiently on the waste heat itself.

  So the pipe above was probably filled with high pressure methane gas. How does it help us escape? I couldn’t see any obvious use for it other than as a distraction. But it was a very dangerous distraction. It could kill us. Then I realized that we were going to die anyway within a few minutes, at least this gave us a chance however small to escape being cornered, and it may even enable us to find some other way out.

  I wanted to do this myself. It was too dangerous to ask Lt. Ma to do this, but I was the only one skilled with the sword, and was needed here to keep the aliens at bay. So I instructed her in what needed to be done. I knew she understood the risk we were taking, but she also knew our dire situation.

  Thankfully the aliens had used very little metal in their construction. I could understand why this was so. Titan did not have any metal on the surface to mine. Any metal you use will have to be brought with you, which is heavy and bulky to carry from space. They had instead made most of their structures from the same material that we had encountered lining the tunnels.

  It had the texture between a hard plastic and hard rubber. It was slightly flexible in feel. It didn’t feel as strong as steel or even concrete, but I suspected it would be able to take a lot of compressive stress, which is what is required to build a robust living habitat. As we had found out using my sword earlier, this could be punctured if pipes are made out of it.

  Lt. Ma tried the same strategy with the pipe. This pipe however had insulation made of some kind of ceramic outside, so she had to hammer very hard with her gun to even crack it. Inside the pipe was made of much thicker material, which she had to poke again and again with her bayonet.

  It was tough going and her knife broke, but she managed to make a small hole after a lot of time. The gas in the pipe was a high enough pressure, that she could hear a slight hissing on her external microphone. Lighting the gas was tricky, and she started from a point very far and sideways to the gas leak. It took her a few tries, every time coming a bit closer, until she succeeded.

  The result of the ignition was not dramatic initially. The fire spewed out horizontally, tracking the trajectory of the leaking gas for a meter or two, but no explosion or raging wildfire. Ma was relieved that there was no explosion, but then driven to tears as she saw the last hope of ours come to nothing. She ran back and was letting us know in a choking voice, when a dull but loud pop was heard along with her startled shout.

  The heat of the fire had weakened the already fractured pipe around the hole, and the pressure inside the pipe was finally able to blow out a much larger section of the pipe, which resulted in the dull pop we had heard. However what followed after that, could be described as what
you westerners would call a hell fire.

  Lt. Ma was literally climbing on top of us to escape the fire, and we in turn were pushing ourselves into the aliens, whom we had been running away from all this time. The aliens could easily have caught hold of us and crushed us, mauled us and killed is in a hundred different way, if not for the fact that they were equally busy running away from the fire.

  The aliens must have realized what had caught fire, because they were not just withdrawing to a safe distance to continue the fight, they were trying to get the hell out of there.

  We went a level below and hunkered down, wondering what to do next. We decided to wait and see how far the aliens retreated, before making a move. The heat of the fire was getting worse. It was uncomfortable inside the suit even one level down. It was at that point we heard the first explosions.

  They were not huge ones but a lot of small explosions all along the pipe we had lit, starting from the point we had lit running along both the directions. Just as we were getting used to the explosions, it was replaced by a howl. It started softly initially but very quickly it sounded like the howl of a tornado. I could see ice snow and debris swirling around our pillar.

  I looked up and down and immediately found the source of the noise. The flames and explosions had breached the air tight seal at the place where the pipe exited to the atmosphere, and the air of Titan was rushing in.

  The atmospheric pressure inside the habitat was at about 70% of what we have on earth, which meant that with an atmospheric pressure of 150% of earth outside, air was at more than twice the pressure outside compared to inside, and it was rushing in howling to equalize.

  Now I realized why the aliens attacking us were in such a hurry to leave. None of them had suits on. We were the only ones with suits in the chamber other than our original pursuers. It worried me that I could no longer spot those original pursuers in the chaos.

  But I had bigger worries. With the atmosphere leaking, this chamber will run out of oxygen soon, and the fires would die out. I could not predict when, but it would. If the aliens have designed their habitat well, they would have some mechanism to seal of this chamber to prevent their entire habitat from losing atmosphere.

  If they did that right now, we would be sealed and permanently trapped in this chamber. Suddenly it became crystal clear to me what the panic of the aliens was the moment they saw the fire! They were not running from the fire, they were running to get out of the chamber before it got sealed! Unfortunately the realization came a bit too late for us.

  As we rushed to exit the chamber ourselves, and must have descended just about one level, when we heard a low rumble from the direction of the entrance to the chamber. In the dim light, enhanced by fires still raging around, it was not hard to see the collapse of the entrance with loose rubble piles blocking the area near the entrance completely. This was their mechanism for compartmentalization of their habitat. Logical, brutal and efficient. I looked around the slowly dying fires at this huge chamber which was now likely our tomb.

  We must have been sitting on the floor of the level for over five minutes, exhausted and despondent, silent in our thoughts of the imminent death, when the radio crackled in our ears and jolted us out of our gloom.

  It was Major Takamori giving instructions for the retreat, and broadcasting the rallying point on our HUD! Ever since we had entered this infernal place, we had been cut off from the radio, as expected being deep underground. Now we could hear the radio, which meant there was an opening to the outside!

  The exhaust vent of course we all realized immediately! We ran the two levels up in the low gravity of Titan in no time and saw it for ourselves. The fires in the chamber had almost all died out with a flicker here and there visible. The vessels with the aliens inside had cooled down, we knew by switching to IR. There was no light in the chamber. We were alternating between IR and our helmet lights.

  When we reached the top, we could see a spot with the orange glow of Titan’s atmosphere. It was the sweetest light of my life. We traced the pillar with our head lamp. The pillar was still standing but there was a large hole all around it on the ceiling, leaking the light of Titan’s atmosphere.

  The ten meters on top would have been a treacherous climb of the pillar was on earth, but in the one seventh gravity of Titan it would not be difficult at all, if we found even small hand and foot holds. The fall all the way to the bottom of the chamber would still kill us in the low gravity, if we were not careful. The ruined exhaust pipe provided us with ample handholds and we were quickly on top, jumping out the last few meter with ease.”

  Chapter 25

  Fight to the death

  The first thing that Daniel noted about the missile that was following his ship, was that the thing was huge, really huge for a missile. It was either a very huge bomb, and he could not even imagine its yield if it was a thermonuclear bomb, or it had lots of rocket fuel.

  It was bad news either way you looked at it. He needed estimates if he would have the chance to outrun it, so he shouted out. “Dubois, I want a mass and volume estimate NOW. Marcello… spectral analysis of its reaction mass ejection. What kind of rocket fuel is it using?”

  Lt. Marcello was the first to reply. “Sir the spectral analysis strongly suggests a solid fuel rocket with more than 90% probability, and the chemical signature is of ammonium perchlorate. They are using the exact same rocket fuel as our missiles sir!”

  Daniel was relieved and told Marcello. “It shouldn’t surprise us Lieutenant, chemistry is the same across the universe, and looks like both our races have come to the optimum solution.”

  Justin reported in a minute later. “Sir the estimates on length and diameter are on your screen, but they are visual estimates, there is a high variability from the actual dimensions possible. Basically it is very big for a missile. It is about the same size as our Sentinel probe was. The missile may even be bigger.

  Daniel next gave a task to his XO, which he was good at. “Francis, now you know the volume of the missile. Give me an estimate of the yield if this was a thermonuclear device. Make two calculations one assuming 50% of the volume is the bomb and the other with 90% of the volume as bomb.”

  Then he turned back to Marcello. “Lt. Marcello, now that you know what fuel it is burning, as the propulsion expert I want you to estimate the amount of fuel it has compared to us, assuming 50% of the volume is engine and fuel and also assuming 90%.”

  Daniel turned towards his XO to see him shaking his head vigorously in disbelief. “What is it Francis?” Daniel asked.

  “This does not make sense. Even at 50% volume, the yield of the bomb would be more than 300 Megatons, which is ridiculous and would have several design problems. There should be no need to put such a huge bomb to kill any ship let alone a tiny ship like ours. It can kill a small asteroid. At 90% volume the figure gets absurd.” Francis was saying mostly to himself.

  Daniel heard what Francis was saying. He turned towards Justin who hesitating to say something. “Out with it Justin, this is hardly the time to hold anything back.” Daniel encouraged him.

  “Sir there could be a reason to have a ridiculously large bomb. As you know that most of the energy of a bomb is wasted in space, only a small fraction is delivered to the ship due to the geometry of the blast. That is why we are developing focused bomb.

  There is another problems with bombs in space due to physics and geometry. As you know sir, all radiation and heat, including radiation from a nuclear blast follows the inverse square law.” Justin hesitated looking at both Francis and Daniel to check if they were following.

  Daniel was sure Francis was following, he himself however needed some help. “Give me a quick refresher please.”

  Justin continued enthusiastically. “Well for our purposes it is enough to know that to get the same damage on a ship if you exploded the bomb at double the distance, you will have to have a bomb 4 times the size. Similarly to get the same damage at 3 times the distance you need a bomb 9 times
the size.

  You simply have to square the number which increases drastically as you go up. For example to get the same damage on the enemy ship from a 10 times distance you would need a bomb 100 times as big. So I was wondering, what if this bomb is designed to do damage not by precision targeting but from a distance.

  Our earth missiles are designed to kill earth ships made of similar technology, so this alien missile must be designed to kill another ship with similar ship like their own. We know that a 3 megaton bomb is just about enough to do serious damage to their ship, what if this missile is also aiming for a similar yield, just from 10 times the distance. That would explain needing 300 megaton bomb.”

  Daniel looked at Francis his go to man for all things scientific, and he was nodding in agreement. “I agree sir, it could certainly explain such a mega bomb. I just did a mental calculation. A 300 megaton bomb would do serious damage to their hull from over a kilometer in space. Two Km is probably a survivable distance for their ship from such a bomb.

  For a ship like ours 5 Km is probably survivable, but the radiation may still kill the people inside. I would say we shouldn’t let a 300 megaton bomb get any closer than 7-8 Km. With this new insight, an even bigger bomb inside that alien missile no longer sounds ridiculous. I say we need to keep a 10 Km distance with the missile.”

  Daniel sighed. That certainly created a lot of problems in their planned maneuvers for evasion. He better let the other know about it, especially Jiānjué which had two of those monsters on its tail. The Charles Martell may actually be more vulnerable, it was skimming the atmosphere, where a bomb blast would be more devastating.

  “Justin, let the other ships know what we know. I don’t think the Martell has turned round the corner yet, so they should be able to hear us. This is especially important for them.” Daniel ordered Lt. Dubois.