“Watch out, Adam,” I warn him. “Ninety meters, thirty seconds.”
Adam’s heartbeat is surprisingly calm again. The boy obviously can focus well.
“Thirty meters. Countdown,” a computerized voice begins counting backward from ten. At the count of zero, Adam jumps in our direction of travel, holding the harpoon far in front of him. This maneuver is calculated to give Adam a slight head start over Fred.
“Approaching target,” Adam says. “Contact in three, two, one, zero.”
I involuntarily expect a sound, but the charge detonates in complete silence. The harpoon enters deep into Fred’s surface. At least that is what it looks like as seen from the spaceship.
“Line pressure within the tolerance range,” Adam reports.
The line connecting the harpoon and the spaceship is briefly subjected to enormous pressure, but it does not appear to be damaged. What about the asteroid’s rotation? I wonder.
“Line is taut. Registering vertical course component,” Adam says.
Fred is rotating at only half the speed, but it is rotating and therefore pulling Messenger closer. The spaceship must not get too close to it.
“Adam, return to the ship,” I order.
I can see Adam hesitate. He receives the same messages as I do and understands that something is wrong.
“Come back. You can’t do anything about it,” I tell him. “We have to wait and see.”
Adam lets his own line pull him back to the hatch, but he does not enter the ship. “We can’t just wait,” he says.
Adam reaches into the hatch and picks up the backup harpoon made by the fabricators in case the first one failed. He slowly stands up and turns around his axis. He is looking for something. Then he jumps off. Now I realize what he is looking for: the other end of Fred. Force and counterforce, I remind myself. When he is close enough to the asteroid, he pushes the harpoon into the rock and the charge detonates. If we are lucky, this will compensate for the rotation, at least so much that the control jets of Messenger have a chance of overcoming it. Couldn’t fate let us be lucky at least for once?
“Rotation almost zero,” the automatic system reports. Adam has done it!
“Great work,” I say, but Adam does not answer. Now I realize why. His line has wrapped itself around the line of the second harpoon. A stupid accident. The motor inside the hatch pulls on it, making everything worse. I see Adam frantically trying to cut the line of the harpoon.
“Adam, stop!” I say, “It’s the wrong line. That’s monofilament, so you’ve got no chance.” I feel a shiver run down my spine. I have to recommend something absolutely forbidden to Adam.
“Cut your own line!” I insist.
Adam pauses for a moment. He can hardly believe it. ‘Never without a safety line,’ that is the iron-clad rule. But he does not hesitate long and starts sawing on his own line.
“Hold on to the harpoon line with your feet, like a trapeze artist,” I instruct him. “Otherwise you will fly off once the line is cut.” I don’t know whether Adam ever saw an image of trapeze artists, yet he hooks his feet around the line.
“I made it!” he says. I see an end of the line swinging sideways.
“Now carefully pull yourself toward the hatch,” I say. “Always have one hand on the line, never let go with both. It is only five meters.” ‘You’ve got time,’ I want to say, but then something beeps frantically inside my head.
“Collision warning,” the automated system reports.
“Govno!” I exclaim. Shit! A small asteroid is approaching from ahead. It is not clear whether it will hit Adam, but it would be extremely dangerous if it collides with the line the boy is holding on to.
“Adam, go! You have three seconds. Now!” Perhaps it is the panic in my voice, perhaps Adam can really react this fast, but he abandons any precaution and pulls himself with both arms and full force toward the hatch. I cannot hear him breathing—he is probably holding his breath due to the effort.
“All clear,” the automatic system reports the moment Adam reaches the hatch. He utters a long sigh.
“Congratulations, that was fantastic,” I say. Adam drops down without a word, and the hatch closes behind him.
“This was my first and last spacewalk. Who came up with the stupid term, anyway?”
I am proud of my son.
November 21, 18
The clock is ticking, and it is frustrating. Proxima Centauri is very predictable about its cyclical eruptions, but we have to keep to a sedate speed due to Fred’s struggles through the mass of its many co-travelers. It is doing great as a protective shield. While we cannot directly see the collisions, we can measure them—the shockwaves are transmitted to the rear side of Fred. Each collision that is at least partly within its direction of travel slows down the asteroid.
Here is the paradox of our situation: The slower Fred becomes, the faster we move. A lower orbital velocity leads to a smaller orbital radius, and that is exactly where we want to go—the inner zone of the system, on the other side of the asteroid belt. Thanks to our dual harpoon assembly, Messenger faithfully follows each of Fred’s braking maneuvers. We should have planned to use two harpoons and two lines from the very beginning. Always remember: Plan B should be at least as sophisticated as Plan A.
I watch the giant boulder that travels ahead of us, clearing the way. I feel a little like Captain Ahab following Moby Dick wherever he goes. However, we are going to cut the ropes once the ‘whale’ has led us through these shallows, and afterward, Moby Dick will go his own way. Did we interfere with its existence in a significant way? Perhaps it would have become the core of a new planet that would form in this orbit? In the end, though, Fred will have to follow a lonely path at the edge of the asteroid belt, but I probably shouldn’t worry about it. Realistically speaking, it is improbable for a planet to form this late in the history of a solar system.
Adam has changed since his experience in space. He seems to have matured from a boy into a man. He speaks even less than before, but I notice he is no longer afraid of assuming responsibility. He also seems to have learned that preparing as comprehensively as possible can be helpful in dangerous situations. Now he is actively participating in classes, just like Eve does, and is well on his way to making up for lost time.
Eve both admires and envies him. She did not have the chance to prove herself, and she resents me for it. I can understand this because I made the decision. I notice, though, that both of them are drifting away from me. Even though I know I should be proud, this sometimes keeps me awake at night, to the point where I have to manually force my consciousness to rest. At least this is an advantage over human existence—I do not have to suffer any more sleepless nights like those I used to experience before important deadlines.
These days we focus our lessons on our arrival at Proxima b. I enjoy applied mathematics, but my two pupils do not like it as much.
“How high do you estimate the degree of complexity for approaching Proxima b?” I ask.
“If you put it that way,” Adam says, “it is complicated.”
“Can you give any reasons for that?”
Adam first ponders the issue and then replies, “The planet moves around its star with a specific velocity. We have to match that velocity.”
“That’s good,” I say. “Which velocity are we talking about?”
“You mentioned an orbital period of about 11 days,” Eve answers, “and a distance to the sun of slightly less than half an astronomical unit. That’s approximately 70 million kilometers.”
I correct her, “Not quite. It isn’t 50 percent, but 5 percent of an AU.”
“So it’s seven million kilometers. So the planets cover it in 11 days, which amounts to 60 times 60 times 24 times 11 seconds, approximately 2 times pi times 7 million kilometers. 46 kilometers per second, I would say.”
Eve is good at mental arithmetic, and I praise her. “By the way, this is 50 percent faster than Earth,” I add. “What happens if we are slow
er?”
“Then the planet leaves us behind,” Adam answers.
“Oh well. But if we want to land, then what would this mean for our velocity?”
“It must be below the second cosmic velocity.”
“Correct, Eve. What does this mean in practice?”
“Hmm, I don’t know the radius.”
“Just estimate it based on Earth,” Adam interjects. “There the velocity would be 11.2 kilometers per second. With the same radius, Proxima b should weigh about 1.5 times as much. If we factor out 1.5 from the square root, then we would get 1.2 times the escape velocity of Earth, or about 13 kilometers per second.”
“Good deduction,” I say. “If you are missing a parameter, you just have to find a different way. But do you see what this means?”
As quick as a shot, Adam replies, “We have to decelerate from 46 kilometers per second to 13 kilometers per second in the shortest possible time.”
“Why in the shortest possible time?”
“Because otherwise the next flare will get us.”
December 2, 18
I only took us 19 days—instead of the anticipated 21—to make our way through the asteroid belt, and this consequently extends the time period for finding a safe shelter from 14 days to 16. The maneuver ahead of us is still anything but easy. In Earth’s solar system, if you were traveling on the way to Mercury, the innermost planet, you would use the gravity of both Venus and Earth to decelerate accordingly. Here, though, we can only use the direct path, as there is only a single planet.
Is there a better option? I examine the diagram of this simple solar system from all sides. The only object besides our destination is the star itself—the distances here are not that large. Would it be possible to use the gravitational pull of Proxima Centauri to decelerate as strongly as possible after an approach with maximum speed? The red dwarf has only 12 percent of the sun’s mass, but it is still far heavier than any planet in Earth’s solar system. Shouldn’t this be enough to capture a small ship like ours and forcefully slow it down?
The basic concept is to use a strongly elliptical course around Proxima Centauri. At the two cusps of the longitudinal, i.e. primary, axis of such a trajectory, the spaceship is particularly slow, while it is especially fast at the cusps of the secondary axis. Therefore one of the longitudinal cusps must be located near the planet’s back side. When we get there, Messenger needs to be slower than 13 kilometers per second in order to be successfully captured by the planet.
How do we reach such a trajectory? Calculating the specific numbers is a task for the navigation software. Additionally, there is one important condition: We have to be able to land on Proxima b prior to December 17th. I order the calculations and allow the software to use the quantum computer. Three seconds later I get a result. I do not like it.
I call Adam and Eve into the command module. They are currently exercising in their cabins, which by now are subject to a terrestrial gravity of 1.2 times. They come right away.
“The navigation software has calculated a few possible trajectories to Proxima b,” I say, displaying all the variants on the screen.
“It doesn’t actually look too bad,” Adam says.
“I have already left out the options that looked really bad.”
“When I look closer,” Eve says, “I see the problem.”
“Yes?” I do not want to influence her.
“The secondary axis is very short. Therefore we move dangerously close to the surface of the sun.”
“Yes, the red dwarf has a diameter of about 200,000 kilometers,” I confirm. “If we want to exit at the cusp of the main axis, which is 14 million kilometers, at a speed of only 13 kilometers per second, we have to get within 200,000 kilometers of the surface.”
“That is one third less than the distance between the moon and the earth,” Adam says.
“Yes, but we are dealing with a relatively-active star, not a boring planet. Most likely we will dive into the hot atmosphere of the star.”
“What kind of damage is to be expected?”
“That’s hard to say, Eve. We know too little about Proxima Centauri. If we are lucky and the star is currently calm... at least we are crossing this region at the highest possible speed.”
“Speed doesn’t help us if Proxima Centauri burns our ass,” Adam said.
“If we are too slow, we get roasted by the flare,” Eve retorted.
I have a crazy idea, and if we are clever about it, we can save a lot of time. As far as protection against solar flares is concerned, there is hardly a safer place than the far side of Proxima b. There the entire planet shields us from the solar fire racing toward us. A flare lasts less than an hour, so we won’t have to hide for long. We actually just have to be at the right place at the right time.
I explain my idea to Adam and Eve.
“Sounds logical,” Adam says. “That’s exactly what we should do.”
“If I understand correctly, it all depends on extremely precise timing,” Eve explains. “We have to run the trajectory calculations several times. If we do it, we should use the time gained to increase the distance from the sun.”
“By how much?” I ask her.
“As much as possible—100 percent. It is totally sufficient if we get to safety behind the disk of the planet at the exact moment of the flare.”
December 10, 18
So far, the plan is working out—we have just reached the point farthest from Proxima Centauri on our elliptical course. Our orbital velocity is 12.9 kilometers per second, and the radial velocity with which we move away from this sun will soon reach zero. The gravitation of the red dwarf threw us far into space, but it won’t let us escape and instead is bringing us back. This will further accelerate us day by day, pulling us closer to the star until we have reached our maximum velocity and race by, close to its surface. There are exactly four days left until that point.
Currently, our distance from the red dwarf is greater than that of its planet, Proxima b. The planet cannot be seen because it is directly behind its sun, as seen from our perspective. I use all of the spaceship’s sensors to examine the red dwarf. Due to the planet’s dense atmosphere, we will never get this clear a view of this sun once we have landed. Proxima Centauri will determine our existence with its life-giving energy, but also with its potential as the great destroyer using X-rays and flare eruptions.
I am always surprised at how diverse the universe is. On the one hand, Proxima Centauri is a main-sequence star, just like the sun. This means that its interior burns hydrogen into helium, but the similarities end there. Due to its size, one might expect a short lifespan for Proxima Centauri, yet the very opposite is true. The star uses its hydrogen supplies so sparingly that it might reach an age of four trillion years, about 300 times the current age of the universe. When our sun gets ready to swallow Earth, in about 7 billion years, Proxima b might be a safe alternative.
I focus the image on the glowing ball we are orbiting. It is hard to believe it is only one and a half times the size of Jupiter, since its gas is so densely packed. The image changes based on the wavelengths I use to observe Proxima Centauri. In the visible range I noticed a dull, weak white, while in infrared the star gets brighter, much brighter. But there is also something happening at the other end of the spectrum: Proxima Centauri radiates a lot of UV and X-rays, with the latter being even more copious than those of the sun. And then there are the metallic spectral lines that tell us about the past: Proxima Centauri seems to belong to at least the grandchildren’s generation of the star population.
I turn around. At least it feels that way to me when I look backward, even though I have been without a body for a long time. I am looking for the place we are coming from. To do so, I have to search in the constellation Cassiopeia. From here the constellations look surprisingly like I remember the night sky of Earth.
Even though we have been traveling for so long, we have only taken a tiny step. And there it is, a bit below the typical
W shape that makes the constellation so easy to find: A white, main-sequence star like many others, apparent magnitude 0.4, about as bright as the red supergiant Betelgeuse in the constellation Orion.
December 14, 18
We are racing above the surface of a star. No human has ever been this close to one of these gigantic fusion powerplants that have been illuminating space like beacons since the end of the Cosmic Dark Ages. Looking downward is both fascinating and frightening to me, a reminder of my long-ago approach to Jupiter’s moon, Io. Back then we orbited the gas planet at about the same distance as we do now, but Proxima Centauri is 50 percent larger. The storms raging in Jupiter’s atmosphere are nothing compared to the gas movement in the outermost shell of this core.
Jupiter could be compared to an onion—what happens in one layer hardly affects the next one—but Proxima Centauri is a glowing agglomeration of gases. The enormous heat created in the interior by the fusion of hydrogen atoms is moving outward. Yes, the star is too dense to radiate the heat from its interior. The heat has to fight its way to the outside by initiating enormous currents that transport hot gas outward into cooler regions, hot gas whose components are charged, and whose movement, therefore, creates huge magnetic fields. These fields burst like bubbles on the surface, flinging material into space as solar protuberances.
At a distance of some 250,000 kilometers, we are clearly outside the range of these normal protuberances. No one can exclude the possibility of a particularly strong magnetic field discharging, though. If this were to occur, we would see the millions-of-degrees-hot spurts of solar matter racing toward us, but we could hardly escape them. So I enjoy the unique chance to study this red dwarf from such a close distance. But while the disk of Proxima Centauri hangs below us and almost completely fills my field of vision, I cannot suppress a feeling of unease.
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