“Braking maneuver.”
The force of the main engine pushed her strongly against her safety harness. At a height of 1,500 kilometers, the sensors reported the first molecules of the atmosphere. Francesca tried to keep her eyes on the monitor. The face of the moon they were approaching at supersonic speeds did not change, though the disk was getting larger and larger. Behind her she heard one of the two men moan.
Watson gave them a short break and deactivated the engine. In free fall, the lander accelerated again. Out here, where the atmosphere was still thin, they could do it without burning up.
“Second burn phase,” Francesca ordered, after Watson indicated the suggestion on the display. This was a bit frustrating, because the computer basically issued the commands.
Titan filled the entire screen at an altitude of 450 kilometers, a featureless orangish-brown disk. They traversed a layer of haze. The temperature sensors reported 320 degrees at the bottom of the lander, no reason for concern. From now on they must not move any faster, just slower.
They reached the cloud layer at about 200 kilometers. The side cameras no longer showed images. They had entered what was basically a single cloud stretching around the entire moon. Here, the ultraviolet, high-energy radiation of the sun broke up the many methane molecules that were in the atmosphere. The fragments reassembled themselves into complex organic molecules, a kind of primal soup, which at higher concentrations had the consistency of tar.
The image from the camera located at the bottom of the lander was blurred. Watson warned them these molecule chains interfered with the sensors. At 160 kilometers, the AI reported, “Radar lock.” On the ground radar, they could see the profile of the target region, a valley between two mountains somewhat south of the equator. The land formations here seemed to be much smoother than on Enceladus. It was noticeable that erosion was constantly at work in the dense atmosphere, which rounded off the craggy structures. The coating on the cameras and sensors increased. The radar would not be bothered by it, but it felt dangerous to blindly race toward a strange moon. Francesca grabbed the armrest of her seat. What if it turned out the radar was wrong? To her, it seemed to be careless rather than courageous to rely on a single source of information.
“Watson, alternatives?”
“A v delta of 160 meters per second would probably remove the organic layers.”
The AI wanted her to ‘step on the gas pedal.’ The slipstream—but more particularly, the friction-generated heat—could then once more provide a clear view for the cameras.
“Create v delta as calculated, Watson. Watch out, guys, it’s going to be a bumpy ride.”
Francesca was always the epitome of calmness when things got tricky. She wasn’t less afraid than the others, but she only experienced her fear with a delay, once everything was over.
“Ahhhhh,” Martin hollered from behind her. Francesca knew the reason for his reaction—it felt like the seat was being ripped away below her, but she was still sitting in it. Watson had to correct the course again and again using the control thrusters, as high winds hit them from the side.
The maneuver was successful. The cameras could see better now, and the rough descent had been worthwhile. Now, at an altitude of 40 kilometers, they came through the layer of haze. They were almost there. In front of them lay a desert landscape with seemingly endless dunes. It looked like one of the large, sandy deserts on Earth, though in evening twilight, since the thick haze layers only let a part of the already weak sunlight reach the surface. Her target was in the mountains to the west, which Francesca detected at the edge of the screen. Watson had to significantly correct their course, and the control thrusters fired again. At a height of 16 kilometers they encountered a surprisingly strong current blowing eastward. Back when Huygens landed, the probe had not noticed this current.
Francesca expected the message before Watson said it—they would not reach their planned landing site. The short acceleration phase had quickly brought them into the denser surface regions, where the control thrusters worked less efficiently, and there was the eastward current to contend with. The AI confirmed this on the display. It was not sure whether they would be able to cross the mountains in the west with the lander.
“Landing at the edge of the dune field,” Francesca informed them. They would land immediately, and prepare for a little walk. Considering the upcoming eleven months in the spaceship, this would likely be the last opportunity for it.
“All systems go. Landing site secure,” Watson confirmed.
At an altitude of four kilometers the wind calmed down. The rest of the distance was covered silently by the lander. It moved at only 40 km/h and carefully decelerated, so it would land at no more than 15 km/h.
“High gate.” There was no turning back now.
“Watson, last check.”
Gradually, it became clear they were not dealing with a terrestrial desert here. The dunes appeared to be huge, but there seemed to be enough space between them to land safely.
“All systems go. Deceleration vector as planned.”
Francesca would have liked to have gone to the console to control the landing herself, but the machine was already doing it, and probably doing it better than she could have.
“Status of landing struts?”
“Nothing unusual.”
They were descending towards the huge dunes.
“150 meters. Low gate.”
Francesca looked at the screen of the camera that was aimed downward. The hot jet exhaust seemed to have no effect. On Earth, there would be a small sandstorm beneath them by now.
The monitor showed they were at a height of 30 meters when a black spot formed below the ship. Francesca immediately realized what she was seeing there—it was a lake. The flare of the burnt kerosene, at temperatures up to 700 degrees, was melting the ground. Francesca understood it at once. She should have known. The familiar scene had deceived her. Of course the sand was not sand at all, but fine-grained ice that became liquid after sufficient energy input. For Watson, everything looked normal. The radar upon which the AI relied showed a smooth surface. Yet the engine was burning a hole into the ground that grew deeper and deeper, into which the lander would disappear. The lander would vanish forever, because at ground temperatures of minus 180 degrees, the water would refreeze quickly. The crew couldn’t be saved, and they would never be seen again.
“Watson, turn off engine immediately. Emergency procedure.”
The AI would obey such an order without questioning it. The jet flare disappeared.
“Francesca, are you crazy?” she heard Martin call out, but she ignored him. She only hoped she had not interfered too late, and that the waterhole was not too deep yet. The lander no longer melted its own grave into the ice, but on the other hand, it fell like a stone from a height of 25 meters. Watson counted down the last meters, as it was part of his program. While the AI counted faster and faster, a shiver tingled up her spine. The lander would not softly touch down in the sand, that much was obvious. Below the water puddle, the depth of which she could not estimate, the ice was as hard as steel.
The impact pressed her so deeply into her seat that she got winded. Then, seemingly delayed, but in reality all at the same time, she heard a loud, terrible sound. Steel hit a surface as hard as steel, and the capsule groaned and shifted sideways with a horrible tearing sound that reached the lander via body-borne sound.
Then it was silent. Or did it just seem that way? After her hearing adapted, she noticed the loud warning messages, which must have been going on the whole time.
“Wow, what was that?” Martin seemed to have survived the landing. “Hayato, are you okay?” he asked. The Japanese man mumbled something.
“Watson, turn off warnings and report status,” Francesca ordered.
“Lander module hit the surface at 30 km/h. Structural integrity confirmed. Two landing struts broken.”
“Consequences for the crew?”
“Currently not in mortal
danger. Restart will only be possible after repairing the landing gear.”
“Looks like we’ve arrived,” Francesca said. It was the same sentence she had used after landing on Enceladus. “Rossi to Commander,” she radioed. “Reached surface, target in a distance of about 30 kilometers, two landing struts broken.”
“I understand, ground team. We are going to work on a plan to get you out of there.”
December 31, 2046, Enceladus
It was his impatience that drove him to get up, his tense expectations. If nothing interfered, he would be able to send a radio transmission with full power today. Marchenko inhaled through his nose. No ammonia this time, only his sweat. Time for a change of clothing. It seemed to be considerably warmer on board than yesterday, which was no surprise, because he had turned off the cooling system. At an external temperature of minus160 degrees, it should not be a problem.
Marchenko jumped up and his impulse carried him to the ceiling. Instinctively he threw his right arm protectively above him. He flinched, but the pain was bearable. So far today he had not taken any analgesic, so the arm seemed to be doing better. In his underwear, he walked to the computer in the front section and switched on the monitor. He now had a battery charge of 82 percent, which should be enough. Should he do it right away?
“Take your time, Mitya.”
His voice echoed inside the metal tube that was now his home. It sounded a bit raspy. He cleared his throat.
“Take your time, Mitya,” he said a bit louder. Much better.
He decided he would first check the analysis of the video recordings. He switched to the semantic analysis that ran in the background all night long. The drive icon was not blinking anymore, so the program seemed to have finished its task. It displayed the results on the screen in inscrutable numbers and units, a joy for any statistician. Marchenko selected the menu for the simplified display. The programmers must have expected that at one time even mathematical dummies like him would have to analyze something. First, the software gave an overview of the source material:
Data size 1,223 megabytes
16 minutes of usable material
60 frames per second
57,600 individual frames
The program had run a Fourier analysis on these images—Marchenko scratched his head, since the term meant nothing to him—and found characteristic changes that applied to 23 structures per frame, on average. The structures, Marchenko assumed, must have been the shining spots. According to the software, this resulted in 922,000 semantic units out of a possible 1,324,800 during this period. Thus the redundancy was only 31 percent, which absolutely contradicted the idea that this was random noise.
This sounded important. He probably was supposed to be impressed, Marchenko thought, and continued reading. The low redundancy was an indicator for a highly developed and very formal language. Human language, in comparison, showed a much higher redundancy. As such, what he had seen could be best compared to the formula language of mathematics and chemistry—but it was not intended as a merely factual communication.
Marchenko was impressed by the software’s clever arguments, as if it really knew something about the phenomenon of language. The program even dared to add an adjective—the word ‘poetic’ was the best way it had for describing the character of this formulaic language. He imagined someone, a poet who used mathematical formulas to write poems. Marchenko was fascinated, and he really wanted to know what the glowing dots said to him.
He scrolled further down and found there was a second part of the report that dealt with the content of the communication. For this purpose, the program had accessed any information sources that it could find. Among them was a treasure trove of which Marchenko was not aware, recordings Martin Neumaier had made during the Valkyrie expedition showing a mysterious ‘Forest of Columns’ at the bottom of the ocean.
The software prefaced the second part of its analysis with a warning. There were no indications this had been a purposeful communication. Marchenko might have just listened, eavesdropped on someone talking to himself. This raised a big question in Marchenko’s mind.
Afterward, the program became more cautious. It indicated that it lacked sufficient data to reach a final conclusion. It arrived at one prognosis, though—these might be blueprints. A layperson should imagine this to be similar to information in DNA, which encoded the structure of an entire organism, although with a lot of redundancy. The individual elements, about the nature of which the program couldn’t say anything, would thus have exchanged encoded structural information. Some of the data had a lot of similarity with the recordings of the Forest of Columns.
Error probability: 40 percent.
This was the end of the summary. Marchenko needed to sit down. Up to now he had not really believed what the Valkyrie crew had reported about this strange forest. He rather considered their experiences to be symptoms of too little oxygen in their air, but this forest, whatever it really was, appeared to be real. Marchenko decided to take a look at the recordings stored on the computer. He would really like to take Valkyrie there and see it for himself. These were the moments when he realized why he had loved this profession ever since he was a child.
Right now, though, it was time for a signal to show that he was still alive. Marchenko touched the console. He pitied Valkyrie in a strange way. Valkyrie was like a baby whose umbilical cord was cut too soon. The vehicle was meant to communicate with the outside world via an optical cable, but it had been torn off two weeks back. Then, he had further crippled Valkyrie by building his power station and taking away its intrinsic abilities. Still it provided him refuge without complaint. Marchenko’s expression changed to a sad grin. The loneliness must be bothering him more than he wanted to admit. Now he was thinking of a machine in terms of a living being.
The vehicle was never intended to have a large, efficient antenna, and this now presented him with a challenge. He had to compensate for this lack with pure transmission power. In doing so, he could not even aim at a particular location, but must broadcast into all directions of space. Instead of shooting a bullet into the target with a pistol, he needed to use the available equipment to construct an all-around sphere, the wall of which got thinner by the square of the distance with every kilometer the signal traveled. If he had bad luck, the target for his transmission might, at the necessary moment, be in the radio shadow of a massive object like the giant Saturn looming motionless in the sky over Enceladus.
He did not have any other option. Marchenko presented the facts and his chances in a message that was as short as possible. The facts were clear, but he hesitated when it came to his survival chances. What were they really like? Basically, it all depended on energy. As long as his little power station was working, he was pretty sure starvation was his worst enemy. ILSE would be close enough that they could possibly pick him up in time. He had to assume, however, that the ammonia circuit might fail at any time, due to the cold, the low pressure, or the aggressive chemicals. Then, even with batteries completely full, he would only survive for a few more days.
Marchenko decided to mention this only briefly.
“Survived, I repeat: I am alive. Current position: Valkyrie. Oxygen and food sufficient, limited energy resources. Three days sure survival, five days 70 percent, three weeks 40 percent, longer unlikely. Marchenko, over.”
He would repeat the information three times. This way the message would be short and concise, and if parts were garbled, they could be completed from the rest of the text repetitions. Marchenko read the message once more and turned the 40 into a 60, and the 70 into an 80. He did not want to stress the team aboard ILSE. He did not want his fellow astronauts to rush into danger to save him. Francesca should not die because of him. Then he touched the ‘Send’ button on the screen.
December 31, 2046, Titan
Francesca was panting. The cooling system of her suit was running at full speed. She could not stand still because the sand was tricky. At first glance one might mistake
it for common desert sand, tiny grains of silica, like on Earth. This ‘sand,’ however, was deceptive. It consisted of water ice mixed with numerous organic compounds that had rained down from the atmosphere. The grains had a temperature of minus 180 degrees and only a third of the mass of terrestrial sand.
This made it very challenging for Francesca to advance. Even on Earth it was exhausting to walk through dry sand, but here she sank in much deeper. This could make the sand lethal because the icy material drew heat from her boots much faster than the atmosphere of Titan did. The boots of her EMU were designed for the vacuum of space. While their coating prevented heat from radiating out, the material was unable to prevent heat transfer when in direct contact. It came down to this; Francesca needed to keep moving so she wouldn’t sink into the sand.
After about 200 meters the sand layer grew thinner, and she could take a break. The ground was rising slowly, and soon she would reach the next dune. Strong westerly winds, which blew for seven and a half (Earth) years in Saturn’s springtime and again during each autumn, had formed the ‘sand’ into towering walls. They were as hard as stone. Their slopes were free of the treacherous sand, and were covered only by a thin layer of solid carbon dioxide.
Francesca had agreed right away when Amy suggested this excursion. It was about 30 kilometers to the spot where Huygens had landed 40 years ago. A little trip into the desert, why not? Now she was annoyed that she had agreed to it so quickly, but she also had to admit to herself she would have bought into it anyway. She still thought Martin and Hayato were more skilled at repairing the struts of the lander module. She would have been in the way of the two engineers, and the fact that Martin got on her nerves for being such a know-it-all would not have helped. Before she left, Martin warned her about the peculiar characteristics of the sand. In spite of this, or maybe because of it, she tested how long she could stand still without getting into danger. She barely made it—the fact that the gravity on Titan was only one-seventh of that on Earth allowed her to save herself through a courageous leap.
The Titan Probe Page 8