The Enceladus Mission: Hard Science Fiction Read online

  Finally, a private company specializing in constructing on-demand satellite accessories succeeded in coming up with a solution. Princeton Satellite Systems, a spin-off of the university of the same name, had developed the Direct Fusion Drive (DFD) using only a small budget. This drive system was based on the nuclear fusion of helium-3 and heavy hydrogen (deuterium). This reaction did not produce any neutrons, which would have turned the material of the reactor radioactive sooner or later. Rather, it produced electrically charged protons and helium ions that could be diverted toward the thruster by using magnetic fields, thus propelling the spacecraft. At the same time, this would also generate electricity—two megawatts, for a total engine output of ten megawatts, the researchers at Princeton Satellite Systems estimated.

  The fact that this was merely an estimate initially concerned the leadership of NASA’s Jet Propulsion Laboratory, because the DFD system had never been tested in space. Princeton Satellite System had created a 1:1 model in a lab and started it successfully, roughly confirming the projections. However, the DFD had not yet been used as a spacecraft drive. There had been no need for it so far—on a trip to Mars, the flight time was bearable even with conventional engines, and missions to farther targets had always been unmanned, so speed was not as important.

  Martin had been partially responsible for the first test of the DFD. He had pointed out 27 bugs in the control software to the head engineer of Princeton Satellite Systems. The Japanese engineer, Hayato Masukoshi, was extremely embarrassed by this discovery, and he offered his immediate resignation to the chief executive officer. To the engineer's surprise, though, he was ordered to test the DFD in the weightlessness of space, together with this ‘JPL nerd.’ Some time later, Hayato told Martin how the CEO had described him.

  October 15, 2037, NASA

  Martin had always thought he was in control of his life. If I had known a bit of troubleshooting would sentence me to the depths of space, would I have managed to overlook those bugs? A few memory leaks here, a race condition there. ‘No one ever died from that,’ like Mother would say. In reality, however, a number of people had died because of such bugs, since software entities had been allowed to act independently in critical areas. India’s autonomous robots, for instance, had caused a massacre in a Hindu temple during the Kashmir War. Later, this event had been officially traced to a buffer overflow in the AI. By now the analysis of this source code had become required reading for computer science students. No, it was only logical that Martin found himself here today, even though in retrospect he would never have seen it coming.

  Of course, back then it had been no coincidence that his boss had sent him and Hayato to Tiangong-4. At that time, Martin was being considered a secret hero in his department. He felt uncomfortable about it, but it was a fact and could not be undone. All he had done, he thought, was sit around and press the right key at the right time.

  Naturally, Martin had fought tooth and nail against this assignment into outer space. “After all, it would be sufficient if the Japanese man flew into space,” he argued. Martin believed he would be better able to analyze the data generated by a test run of the drive while sitting comfortably down here in his office, but his boss did not budge. “I haven't even had any basic astronaut training,” he reasoned. When he brought up this point, his boss just smiled as he reached into a drawer and pulled out a letter-sized brochure designed in elegant blue.

  The Adventure of a Lifetime, Martin read, after his boss had silently handed him the folder. “Blue Origin will take you to the edge of space and back.”

  Martin had made the mistake of reading the brochure before going to bed. The thin leaflet advertised space trips in the capsules owned by the e-commerce billionaire Jeff Bezos. They looked elegant and sleek, and the passengers wore body-hugging suits of blue material while smiling at the camera. Training, the brochure said, was completely unnecessary. You must spend two days learning about launch, landing, and safety procedures, and then you could go into space. If only I had researched beforehand who was trying to participate in the Enceladus project, Martin reflected. It appeared Bezos had reserved two of his spacecraft for transport flights. After a boom in the 2020s, space tourism was no longer as popular as Bezos had hoped.

  Martin imagined slowly getting up from his launch couch, carefully floating to the wide observation window, and then promptly throwing up all of his stomach contents. His fellow passengers would turn away from him, partly disgusted, partly amused, and he would be unable to shake off his vertigo for the duration of the entire flight. Even the mere idea made his innards cramp.

  Reality, when it came, turned out to be much worse—and much better. He did not have to vomit, only because his digestive system chose another way out. He had concentrated on his task for 20 hours, the entire duration of the trip. For the whole time he tried to avoid looking into the abyss next to him, below him, behind him, and above him. He did not always succeed, but when he started to stagger, Hayato took his hand. Most of the time, though, Martin's strategy worked. He had felt best when he connected himself with a restraining strap to the external control console of the Direct Fusion Drive, and crawled inside a two-meter-long closed tube that reeked of oil. Then he had been in his element. The engine responded to his commands. He had no problems adapting the launch sequences to the supposed zero gravity. The problem the developers had not been able to solve on Earth was that liquids moved differently up here than under Earth’s gravity. This could be simulated and calculated, of course, and the Japanese engineer had succeeded in doing that very well. However, somebody had to adapt the results achieved by this method to reality.

  “That was it,” Hayato had finally said. Only then did Martin realize he had just spent two consecutive hours in space without getting dizzy. He had not been able to take off the adult diaper he still wore from launch, and now it was starting to chafe. During the landing, though, he was glad he still had it on.

  “Nice trip, see you next time,” the Japanese man said, bidding him farewell.

  Martin shook his head. “No one will ever get me into one of those things again,” he said. “But it was interesting to meet you. We have to talk sometime about the algorithms for the thermodynamic simulation of fluids. You solved that quite elegantly!”

  The Japanese engineer gave him an inscrutable smile and took his leave.

  July 16, 2038, NASA

  The most important task of the Enceladus project was to find the final proof for the existence of life. To do so, astronauts must catch life red-handed, which could only be expected in the salty ocean below the several-kilometers-thick ice crust. How could you dig such a deep hole with the limited resources of an interplanetary expedition, no more than six crew members, and no giant drilling rigs?

  The Europeans had the most extensive experience with such drilling attempts. They had reached a depth of 10 meters on Mars during their unsuccessful quest to find traces of life there. One could not learn very much from this, though. On Enceladus, temperatures were expected to reach minus 180 degrees Celsius. Ice would be as hard as steel, and metal drills would become brittle.

  NASA’s engineers came up with several ideas. They considered, for instance, landing a spacecraft vertically on the moon so the heat of its rocket engines would blast a hole into the ice. The 10-megawatt fusion drives would most definitely be involved in this. A non-flyable DFD prototype was taken to a glacier in Alaska to test the method. The energy proved sufficient for a sizable hole, but the jet of hot air could not be sufficiently focused. Instead, as it went deeper, the hole became wider and wider. It did not form a cylinder, as intended, but a cone with the tip facing downward. The engineers extrapolated that the pit would have to be over a kilometer wide to reach a depth of five kilometers. And how could they keep the rocket engine centered above it as the cone widened? The reason this idea was finally rejected was a different one, however—it turned out the melting water became more polluted by radioactivity than expected, which was not good for most
forms of life. However, the experiment had shown that, against ice, heat was a better weapon than a mechanical drill.

  How could they heat a device for a sufficient period of time? It soon became clear that adding energy once—like filling a hot-water bottle—would never be sufficient, unless one detonated an atomic bomb, or even better, a hydrogen bomb. This meant the drill head had to carry its own heat source. Space exploration had used a reliable, if not particularly popular, method for tapping into an inexhaustible source of heat—the decaying energy of radioactive materials. The engineers searched through their arsenal. Even the Cassini probe that had found the first indicators for life on Enceladus back in 2015 had contained an RTG, or Radioisotope Thermoelectric Generator, that generated electricity through the decay of plutonium-238. Enceladus Life Finder used the same proven technology 16 years later.

  Unfortunately, mathematics threw a monkey wrench into the NASA researchers’ project. How much energy is needed to heat a five-kilometer-deep, almost two-meter diameter ice cylinder to the melting point, and then fully melt it? The crust of Enceladus might as well have been made of iron—it wouldn’t have made the task any more complicated. A best-case scenario showed them reaching a depth of five kilometers in 200 days. To do this, the drill vehicle would have to carry along approximately one and a half tons of plutonium. For the Cassini probe, about 20 kilograms of the highly radioactive material had been enough. The decisive factor turned out to be money. A kilo of plutonium-238 cost about 10 million dollars, so a ton and a half would cost 15 billion dollars and thus devour a big part of the budget, not to mention the fact there was not that much plutonium available worldwide.

  A Nordic spirit creature who leads the honorably slain to Valhalla finally solved the problem—Valkyrie, the ice drill owned by the private-sector company Stone Aerospace. The device had already been successfully tested in Antarctica, though only using an unmanned version measuring 30 centimeters in diameter. The company was confident it could use the design for a model with a diameter of two meters, and that was enough incentive for NASA to finance the project. Valkyrie did not need an on-board heating plant, since it received all of its energy from the outside via a fiber-optic cable connected to a powerful laser. The cable itself must be less than a millimeter thick. It served as an umbilical cord that provided the drilling vehicle with the necessary energy, and also allowed for data transmission. The range was limited only by the length of the fiber-optic cable carried aboard. NASA specialists had demanded 100 kilometers, and in the light of the hundreds of millions offered, Stone Aerospace had gladly accepted any request. However, the space agency itself was supposed to be responsible for an energy source providing several megawatts of power to the laser while the vehicle was on Enceladus. At first the NASA specialists considered, with some misgivings, a small nuclear reactor, but then the fusion drives solved this problem.

  Nevertheless, it took until 2038 before the first large Valkyrie became operational. No one seemed to have the time to come up with a new name, so the old one stuck.

  The initial trial failed in a grandiose manner. In June of 2038, a team of technicians tested a new version on an Alaskan glacier that the U.S. government, for this very purpose, had excluded from national park status. The drill vehicle was transported on a cargo ship and was finally air-lifted to the glacier by a large helicopter. As the technicians tried to unhitch the carrying cable from the helicopter, Valkyrie started to slide. It was a perfect example of faulty planning leading to a disaster. No one had considered that a giant tube of steel might begin to move in an undesired manner on uneven ground. The helicopter carried the drill vehicle back to the cargo ship.

  Afterward, the technicians needed a week to level the starting area and to build scaffolding. The engineers had somehow forgotten that Valkyrie must be placed in a vertical position in order to drill into the ice. They had simply upscaled the miniature model that could be held upright by two men, and made a larger variant. Despite this, the company director, Stone Jr., son of the company founder and reputed to be a hothead, did not fire any employees.

  The second attempt began two weeks later. NASA streamed it live on its website. Martin remembered it for a long time afterward because the result had been typical in a certain way. The helicopter once more flew Valkyrie on-site and placed it on its scaffolding. The drill vehicle was supposed to perform an unmanned run first. An AI was trained to steer it, using the miniature model for practice. The company director himself insisted on activating the generator and switching on the laser it powered. A fraction of a fraction of a second later, the light reached Valkyrie via the fiber-optic cable. It performed two functions at once. It heated a metal plate to melt the ice near the drill head, and it generated electricity by means of photocells to power the pumps that pressed the heated water against the ice below Valkyrie, thus creating a hole.

  The technicians were optimistic and seemed to have thought of everything. In fact, the drill vehicle started moving as planned, and the audience applauded. Director Stone was cautious enough not to join the cheering just yet. The drum, from which the prototype of the fiber-optic cable unspooled, was turning slowly. They were not in a rush. This was only the first test of the new version. There would be many more, during which they could also raise the speed.

  The entire crew was listening. A deep rumbling could be heard, mixed with a constant hissing. The hole dug by Valkyrie was only a few centimeters larger than the vehicle itself. Everything seemed perfect. However, after exactly seven minutes and ten seconds, it stopped.

  “Shit,” Stone said. His face reddened, but he did not utter another word. The technicians looked embarrassed. One of them placed his ear on the ice.

  “Silence!” Stone barked.

  The sensors reported that Valkyrie was stuck at a depth of 87 meters. Suddenly, shrill alarm signals sounded from the control panel, as if the artificial intelligence had needed some time to think this over.

  “Turn it off! What happened?”

  Three of the specialists tried to answer Stone’s question at the same time.

  “The hot water jets are choked with crud.” The diagnosis was too obvious. “Sorry, I meant they are blocked by sediment.”

  “Are you serious?” Stone’s glare seemed to try to burn through the glacier without using Valkyrie. This did not sound like a question, but rather like a threat. All of them must have realized the drill vehicle would not be moving through laboratory ice but through a naturally-grown glacier. Wind and weather deposited fine sand and other small particles on it and the deposits gradually sank down into the polar ice. They not only suspected this, they knew it. The deposits must have clogged the hot water jets much faster than expected and made them inoperable.

  “I told you so,” one of the technicians said, and then quickly put his hand in front of his mouth when the others glared at him.

  “What did you just say?” Stone asked, standing before him with his hackles up.

  “It's a problem of scale. We simply scaled up everything. We thought the small particles might be dangerous for the miniature model, but only large pieces would be a problem for Valkyrie.”

  “Didn’t you simulate this? Why did I not hear anything about it?”

  “Sir, a description of the issue was sent to your inbox on ...” he scrolled through his tablet, “July 10.”

  Stone fell silent, turned around, and scratched his head. He was facing a real problem—the Valkyrie prototype was lost. How were they supposed to retrieve a metal tube weighing several tons from a gradually freezing hole that was 87 meters deep? The fiber-optic cable for the laser was much too thin to be used for pulling Valkyrie up by the scruff of the neck.

  The Director did not say anything else. He spoke to no one and walked down the glacier past the Valkyrie scaffolding. Eight hours later a helicopter could be seen taking off from the cargo ship and picking up a single person at the coast.

  Stone Aerospace pledged to build a new Valkyrie as soon as possible and at its ow
n expense, using the exact design of the old one. Valkyrie actually had all the necessary equipment to counteract the clogging, but the control software had not initiated those measures in time, since they had been unnecessary in the miniature version. Because NASA trusted this private contractor due to its boldness and talent for improvisation, but not for its ability to program an error-tolerant AI, Martin was sent on an official trip. At first he was even happy about that. For the moment, he was still able to suppress the thought that one day he would have to stand on the ice of Antarctica.

  June 28, 2045, Antarctica

  The cold was killing him. Martin glanced backward, and he could still guess where the station was. The other person with him, the station cook, might be surprised if he suddenly ran in the wrong direction, but this was the only way to survive. Small ice darts dug into the few unprotected areas of his skin, even though there was no wind today and the cook had praised the warm weather this morning. Martin felt like a fakir placing his face on glowing embers. He could not tell whether heat or cold was torturing him, but it did not matter, as he would die anyway.

  The cook was now walking ahead of him. At dinner, he had introduced himself as Tadeusz, though Martin had forgotten his last name. He was also one of the leading scientists of the Polish Antarctica Station. In the polar region, no one had just one job. Just as Martin was about to flee the freezing hell surrounding him, the man turned around and spoke to him in English. Martin could not understand what he said and only shrugged his shoulders. Tadeusz spoke up.

  “Marvelous landscape, isn’t it?”

  Martin thought, He can hardly expect an answer to that, can he? He at least managed to nod. The cooking researcher or researching cook laughed.

  “Your first time beyond the Antarctic Circle, isn’t it?”