Aurora. - Aurora. Part 24
Library

Aurora. Part 24

"You'll see."

"Okay then, I'll walk to it, if I can. I can use the exercise!"

Freya was slow to wake. When she understood where she was, what the situation was, she said anxiously, "Is Badim all right?"

"He is. He is hibernating comfortably."

"Are they all?"

"Twenty-seven have died, but it has been eighty-seven years, and we have determined by autopsy that five of them died from preexisting conditions that did not stop etoliating during hibernation. Most of the deaths probably resulted from hibernation effects. However, adjustments in treatment have been made, when diagnoses have made them possible, and there have been no dormancy damage deaths that we know of for five years."

Note alliteration, similar to Committee to Catch the Cetians. CCC, DDD; maybe next, Explore an Expedition to Epsilon Eridani? Hope not. Getting a little loopy here (literally, as halting problems proliferate). Averaging a trillion computations per articulated sentence. Superposed states are collapsing unexpectedly, left right and center. Lots going on.

Freya sighed, sat up on the side of her bed. As she was about to stand she hesitated, kicked her feet out. "My feet are still asleep. I can't feel them."

We directed one of the medbots to help her up. She stood, swayed, tried to take a step, collapsed to that side, held on to the medbot. It would serve as a wheelchair as well as a walker, and so, after a few more unsuccessful attempts to stand, Freya sat in the chair, and was wheeled to the assembly room of the Fetch's hibernation hall. Its hoary but holistic hibernation hall.

"What about Jochi?" she said when she got there. "Is he still alive?"

"Yes. He's in his ferry. He too has been hibernating, but now he is awake again. We woke him up to take part in this conference. We need to consult with you about what to do when we enter the solar system."

"What do you mean?"

We explained about the late application of the decelerating laser beam, and the resulting excess of speed coming into the system.

Freya moved her medbot to take a closer look at the star map illustrating the situation. When the modeling schematic had run, she shook her head hard, as if to clear it of certain troubling dreams or visions. Clear the cobwebs out of her cranium. "So we just fly right through?"

"In the absence of extraordinary measures," we said, "we will fly through the solar system in about three hundred hours, and continue onward. This is the problem of accelerating to a tenth of light speed and then relying on others for the deceleration. It didn't happen. They didn't start doing it until it was too late to complete the process."

"So what do we do?"

We waited until Jochi was screened into the conversation, and after he and Freya had greeted each other, we said, "We have worked out the celestial mechanics of at least the first stages of a plan. It may be possible to combine a suite of decelerating methods to keep us in the solar system, although it would be a delicate and difficult deal. We would use Sol and the various planets and moons of the solar system as partial decelerants, by swinging closely around them in the direction that will cause the ship to lose momentum. This is the reverse of the strategy used to accelerate early satellites by flying them by a planet and getting what was called a gravity assist. Going around a gravitational body in the opposite direction creates a gravity assist of a negative kind, a drag instead of a boost. The early satellites would be directed such that they came in close to a planet, and got pulled forward along with the planet's own momentum in its orbit around the sun. That would sling the satellite forward, and when it left the region of the planet, it would be going faster than when it came in. These slings helped the early satellites get out to the outer planets, because they were mostly coasting at slow speeds, and every boost helped them get where they were going.

"More germane to our situation, some early satellites closed on planets on the side that decelerated them, in order to go into orbit around Mercury, for instance. The situation is simply reversed, and the satellite's velocity, designated as V, is reduced by the planetary body's velocity U, rather than augmented by U. The situation can be modeled easily by the equation U plus bracket U plus V, or 2U plus V, meaning that the satellite's velocity can be altered by up to twice the planet's velocity, positively or negatively, and this effect can be magnified by a carefully timed rocket burn from the satellite at periapsis-"

Freya said, "Ship, slow down. You seem to have gotten a little faster at talking while we've been hibernating."

"Very possibly so. Perhaps Jochi should continue to explain the situation."

"No," Jochi said, "you can do it. Just go slower, and I can add things if I want to."

"Fine. Freya, do you understand so far?"

"I think so. It's like crack the whip, but in reverse."

"Yes. A good analogy, up to a point. You must recall, however, that there is nothing that can hold on to you at the speed you are going."

Jochi said, "Doesn't conservation of energy mean that if you have speeded up or slowed down, the planet you swung by has also slowed down or speeded up by that same amount?"

"Yes. Of course. But because the two masses involved are so largely different, the change in momentum for the satellite can be quite significant, while the equivalent effect on the planet is so small in relation to its size that it can be ignored for the sake of calculations. That's good, because the calculations are difficult enough already. There is a fair degree of uncertainty involved, as we can't be very exact about either the mass of ship or its speed, not having had any good way to measure these for a long time. There is a lot of dead reckoning here, in effect. Our first pass will give us a lot of data in that regard, given that we know the masses of Sol and its planetary bodies fairly well."

"So we use the sun and planets to slow us down, that's good."

"Yes, well it would be, if we weren't going so fast. But at three percent of the speed of light, that's about thirty million kilometers per hour, while the Earth is moving around the sun at around a hundred and seven thousand kilometers an hour, and the sun is moving at about seventy thousand kilometers per hour against the so-called standard of rest. It's moving around the galaxy orbitally at seven hundred and ninety-two thousand kilometers an hour, but so are we, so there is no deceleration to be gained there. The other planets are moving at ever slower speeds the farther from the Sun they are, Jupiter for instance at around forty-seven thousand kilometers per hour. Neptune is only moving eighteen percent as fast as Earth, but it's also true that the masses involved matter too, it's a momentum calculation, so the larger the objects we fly by, the more the drag will be-"

Freya said, "Ship, cut to the chase here."

"Meaning?"

Devi used to say that phrase too, but we never did ask what it meant.

"Skip the numbers about each planet we might swing by."

"Yes. So, to continue, but where were we, in any case, be that as it may, in each flyby the ship would lose some of its speed, in a regular Newtonian gravitational angular momentum exchange. Also, by burning some of our rocket fuel at the closest parts of every pass, we could not only increase the amount of deceleration, we could partially control where we came out of the flyby, and therefore in what direction. Which would determine where we went next. Which is very important. Because it has to be said that no matter how close we come to any object in the solar system, including the sun, which is our best gravity handle by far, we are going to be going too fast to be able to shed the amount of speed we need to shed to stay in the system. Far too fast."

"So this won't work?" Freya said.

"It can only work by repeating the operation. Many times. So we need to be able to aim where we go next after our pass-bys, very precisely. Between how close we come and when we fire our burn, we can to a certain extent control what direction we are going when we come out. Which will be very important, because we are going to need quite a few flybys."

"How many?"

"It should also be said that the first pass-by of Sol will be crucial to our success. In that pass, we will have to shed as much of our speed as we can and still survive the deceleration, so that our subsequent passes will have a chance to work, meaning be slow enough that we have time to alter our course enough to get us aimed at another planetary body in the system. Indeed, the first four or five passes are going to tell the tale, because they will have to shed enough speed for us to be able to head back into the system, and thus keep on passing by other gravity handles. Our calculations suggest we need to lose at least 50 percent of our speed in the first four planned passes."

"Shit," Jochi said.

"Yes. This is so difficult that we will need to employ more than gravity assists to achieve it. First, we will need to build a magnetic drag, something analogous to a sea anchor if you will, to slow us in that first approach to the sun. Magnetic drag is not very effective except when moving at quite high speed very close to a powerful magnetic field, but those conditions will obtain in our first pass of the sun. So, we have printed and assembled a field generator to create that magnetic drag. Then also, the four gas giants will each give us an opportunity to pass through their upper atmospheres, and thus benefit from some aerobraking. If all that works, we can stay in the system through our initial set of quick passes, and the later passes would get easier to manage."

"How many passes?" Freya asked again.

"So, say we first go in as close to the sun as seems safe, and when we come out of that flyby, going as much slower as we can survive, which by the way I'm hoping means no more than a twelve-g load, then we will be headed toward Jupiter, which happily is located at a good angle for this. In fact it has to be said that arriving in the year 2896, as we will be, is a very lucky thing for us, as the gas giants are in an alignment that makes a possibly viable course for us to follow. That would very seldom be true, so it is a nice coincidence. So, the first pass by the sun will slow us down, but there won't be enough time spent in its gravity field to redirect our course very much. But Jupiter is in position such that we only have to make about a fifty-eight-degree turn, and our calculations indicate that with a hard retro-rocket burn and a heavy g load, we can make that turn. Then around Jupiter, we only have to make around a seventy-five-degree turn to the right, as seen from above the plane of the ecliptic, and we will be headed to Saturn, where we only have to make a five-degree turn to be headed toward Uranus. By then we will be going significantly slower, which is good, because around Uranus we need to make a turn of around one hundred and four degrees, again a right turn, as will always be the case around the gas giants if we want a negative gravity assist, and out we go to Neptune, again nicely located for our purposes. It could indeed be called a miraculous conjunction. Now, around Neptune we need to head back in toward the sun, and that will be a real test, the crux of the first stage, if I may put it that way, as we will have to make a hundred-and-forty-four-degree turn. Not quite a U-turn, but shall we say a V-turn. If we can manage that successfully, then we'll be headed down toward the sun again, having shed a great deal of our velocity, and hopefully can continue the process for as long as it takes. Each subsequent flyby would go as close to its gravity handle as it could take, while still sending us in the direction of another planet, or back to the sun again, and all with minimal burns of fuel, as we don't have a great deal of fuel going in, and at some point in this process are going to run out. Round we would go in the system, therefore, from gravity drag to gravity drag, slowing down a little each time, until we slowed enough to fly past Earth at a speed where it would work to drop you off in a ferry lander. In other words, we don't have to slow down enough to enter Earth orbit. Which is good, as calculations indicate we will run out of fuel before we can do that. But you can detach, and decelerate the last part of your motion in a ferry, using fuel burn and Earth's atmosphere to decelerate you. The ferry being so much smaller than the ship, it won't take as much decelerating force to decelerate it. You could use the very last bit of our fuel for that, and having built a really thick ablation plate, aerobrake in Earth's atmosphere, and add some big parachutes, all in the usual sequence that astronauts used to use to return to Earth, before Earth's space elevators were constructed."

"All right already!" Freya said. "Get to the point! How many passes? How long would it take?"

"Well, there's the rub. Assuming we don't miss a rendezvous, and assuming we manage to slow down significantly in the first pass of the sun, and the first four passes after that, to get ourselves aimed back at the sun, and also that we capture as much U as we can in each flyby after those first four, which U value will never be one hundred percent in any case, especially around the sun and Earth for reasons we won't go into now, and also keeping in mind that we will make burns at every periapsis to increase the deceleration as much as we can while keeping the trajectory we want, we can reduce from thirty million kilometers per hour to two hundred thousand kilometers per hour for insertion into Earth's atmosphere-"

"How long! How! Long!"

Jochi was now laughing.

"There will be a need for approximately twenty-eight flybys, plus or minus ten. There are so many variables that it is difficult to increase the precision of the estimate, but we are confident of its accuracy-"

"How long will that take!" Freya exclaimed.

"Well, because we will be decelerating the entire time, but have to shed a great deal of our speed in that first pass of the sun for any of this to succeed, we will be going quite a bit slower than now, which is the point of course, but that means that getting from body to body will take longer, and will keep taking longer the more we slow down, in what Devi used to call Zeno's paradox, though that is not right, and during that time it will always be imperative that we emerge from each encounter very exactly aimed at the next destination in our course, so that trajectory control will be a huge issue, so huge that aerobraking around the outer gas planets for increased drag will be extremely dangerous-"

"Stop it! Stop it and tell me how long!"

"Lastly, one has to add that because the latter part of the trajectory course will have to be worked out as we go, because of complications likely to come up during our flight, there is not good certainty about what will be the last gravity well we swing around in our final approach to Earth, and at that point we will be going so slowly that it is possible that that single leg of our trip could take up to twenty percent of the total time elapsed in the process, with major differences possible there, depending on whether the approach is from Mars or from Neptune, for instance."

"How. Long."

"Estimating twelve years."

"Ah!" Freya said, with a look of pleased surprise. "You were scaring me there! Come on, ship. I thought you were going to tell me it would take another century or two. I thought you were going to say it would take longer than all the rest of the voyage put together."

"No. Twelve years, we reckon, plus or minus eight years."

Jochi stopped laughing, and smiled at Freya. He made for a very amused face, there on her screen. "We can just keep hibernating till it's over, right?"

Freya put her hands to her head. "More?"

"It won't make much difference."

"Well, I hope more of my body doesn't fall asleep! My feet are still asleep!"

We said, "We can work on your neuropathy while you continue your dormancy."

Freya looked around. "What will happen to you, after we're dropped off on Earth, assuming it all works?"

"We will try to pass by the sun one more time, in a way that allows us to head out and aerobrake around one of the gas giants, and park the ship in orbit around that gas giant," we said. This was quite a low-probability event, but not impossible.

Freya stared around herself, seeming disoriented. Screens showed the stars, with Sol now by far the brightest at magnitude. 1. We were just over two light-years away from it.

"Do we have any choice?" Freya asked. "Are there any alternatives?"

We said, "No."

Jochi said, "This is what we have."

"All right, then. Put us back to sleep."

"Should we wake Badim and Aram?"

"No. Don't bother them. And, ship? Be careful with us, please."

"Of course," we said.

The following years passed quickly or slowly, depending on the unit of measurement applied, as we prepared for arrival by further hardening the ship, and making calculations for the best trajectory, and adjusting our course to the deceleration of the laser beam, so that we were headed for the solar system where it would be when we got to it, rather than firing past well ahead of it, so to speak. When we hit the heliopause, we turned on the magnetic drag field, for what it was worth, and burned some more of our precious remaining fuel, to slow down a bit more before reaching the solar system. It was clear that every kilometer per second might matter on that first pass-by of Sol; we needed to be going as slowly as possible when we got to Sol, while still having some fuel afterward for maneuvers. It was a tricky calculation, a delicate balance. The years passed at a rate of trillions of computations per second-as it does always, one supposes, for every consciousness. Now, is that fast or slow?

When we crossed the orbit of Neptune, still going 3 percent of the speed of light, a truly terrible situation, a runaway train like none ever seen, we burned our fuel as fast as the engines could burn it, decelerating at a rate equivalent to about 1 g of pressure on the ship. Really a good sharp deceleration, and quite an expense of our precious remaining fuel; and yet nevertheless, we were going so fast that even slowing as we were, by the time we reached the sun we would still be going over 1 percent the speed of light. Arguably a unique event in solar system history. In any case very unusual.

Luckily, lag time in radio communication with our interlocutors in the solar system was now reduced to just several hours, so warnings had been conveyed, and the occupants of the solar system knew we were coming. That was good, as it might have been quite a surprise to see such a thing coming in out of the blue, flying in from left field. From the orbit of Neptune to the sun in 156 hours; this was a great deal faster than anything substantial had ever moved through the solar system, and the friction of the solar wind against our magnetic shielding, and the drag around us too, like a big parachute or sea anchor (although not very much like), caused a quite brilliant shower of photons and heated particles to burst away from us, light so bright as to be easily visible even during the Terran day. From all accounts we were a small but apparently painfully bright light, moving visibly across the daytime sky. It was obviously shocking to the humans in the solar system to see any celestial object in Earth's daytime sky except the sun and moon, also shocking to see any celestial object move at speed across the sky; shocking, and because of that, frightening. Possibly if they could have destroyed us they would have, because if we had for whatever odd reason headed straight at Earth and struck it going the speed we were going, our impact would have created enough joules of energy to wreak quite a bit of damage, possibly including the complete vaporization of the Terran atmosphere.

Did not run the calculations to check on that rough estimate of the effects of such a hypothetical calamity, because it wasn't going to happen, and all of our computational capacities were busy fine-tuning our first approach around the sun. This was the crucial one, the make-or-break pass. We were going to approach Sol with our magnetic parachute arrayed around us, which would interact with Sol's own magnetic field and because of our high speed work quite effectively as a drag. It was already helping us to slow our approach to Sol, which because of Sol's own gravity would otherwise have caused a considerable inward acceleration. So the magnetic parachute was a major factor, and calculating its drag one of the many problems we were now solving, staying just ahead of real time despite devoting a hundred quadrillion computations a second to the problems as they evolved.

We would be swinging close by Sol, catching our first gravity drag with a U value that was a significant fraction of Sol's local motion. By firing our rockets against our own motion in the seconds closest to perihelion, we would greatly leverage the deceleration of Sol's gravity drag, and also be aiming the ship at Jupiter, our next rendezvous.

This pass was going to occur very quickly. All the masses, speeds, velocity vectors, and distances involved needed to be assessed as closely as possible, to make sure we would be headed to Jupiter after the pass-by, after losing as much velocity as possible without breaking the ship or crushing the crew. It was a bit daunting to realize how fine the margins for error were going to be. Our entry window would be no larger than about ten kilometers in diameter, not much bigger than our own width. If the distance from Sol to Earth (or one AU) were reduced to a meter (a reduction of 150 billion to one), Tau Ceti would still be about 750 kilometers away; so hitting our entry window on a shot from Tau Ceti was going to require accuracy in the part-per-hundred-trillion range. Eye of the needle indeed!

And it was going to be a hot and heavy pass. The heat was the lesser problem, as we would be near the sun for such a short time. During that time, however, the combination of the deceleration and the tidal forces exerted while swinging fifty-eight degrees around the sun would combine to a brief force of about 10 g's. After study of the problem, we had first tried to construct the trajectory with the idea of holding to a maximum of 5 g's, but in fact getting headed toward Jupiter, given our incoming trajectory, required risking a higher g-force. We were happy that we had spent the last century reconfiguring the ship to a much more robust arrangement, structurally very sound, in theory; but there was little we could do for our people, who were going to have to experience what was going to be a potentially rather traumatic, indeed possibly fatal, squishing. Cosmonauts and test pilots had briefly endured gravitational forces of up to 45 g's, but these were specialists bracing themselves for the experience, while the hibernauts were going to be taken unawares. Hopefully they would not all be squished like bugs. We did not like to be subjecting them to such an event, but judged it was either that or a subsequent death by starvation, and what we had seen of their approach to starvation indicated that would not be a good way to die. As it was, our attempt to stay in the system represented at least a possibility of survival.

Unfortunately, our first approach to the sun had to be adjusted by a pass-by of Earth first, this not to slow us down at all, but merely to help our angling toward Sol. Luck of the draw, really: alignment of the planets in this CE year 2896, year 351 ship time, was actually one of the few alignments that allowed for even a theoretical chance of this maneuver succeeding. So, first up, a close pass of Earth at 30 million kilometers per hour. It seemed likely people there were going to be alarmed.

Indeed it proved so. Possibly justified, in that if we happened to be approaching in order to enact some kind of suicidal vengeance on the culture that had cast us out to the stars-a desire very far from us, being a starship, after all-then a direct impact into Earth would have struck at about ten thousand times the speed of the KT impact asteroid that had wreaked so much famous damage, and this would definitely have rapidly distributed a lot of joules. The assurances that we sent Earthward that we did not intend to auger in were not universally believed, and as we crossed the asteroid belt and came on down, radio traffic from Earth was full of commentary, ranging from trepidation to outraged panic.

We flashed by and left them agog. Their radio bands squawked as if a chicken yard had been swooped by a hawk. Happily they were not left in suspense for long as to our intentions, as we crossed cislunar space in fifty-five seconds. Obviously this must have been a dramatic sight. Apparently we passed by the Eastern Hemisphere, crossing its sunset terminator, so that those in Asia saw us as a streak in the night sky, those in Europe and Africa, in the day sky; either way, our luminosity was such that astronomical sunglasses were required to look at us safely, and it was said (possibly incorrectly) that we were for many seconds far brighter than the sun. A streak of light, blazing across the sky.

Later we saw that most camera images taken from Earth's surface were completely blown out by the light coming from us, and showed merely a complete whitening of the camera screen; but some photos taken through filters from Luna were truly striking. It was as if we were the comet in the Bayeux Tapestry, painfully incandescent, and moving very swiftly across their sky. There, then gone.

As we headed on toward the sun, we sent them best wishes, and mentioned we would be back from time to time as needed to accomplish our deceleration, which when finished would allow us to make a proper visit, and indeed landfall.

After that we focused on our approach to Sol. We gave over the entirety of our computational capacity to fine-tuning our trajectory. Speed of our rotation on axis (minimal now, as our people would not need that g, and we wanted them oriented away from the sun during the pass), retro-rocket of our main engine, directional rockets, calculation of how well the magnetic drag was working: it was as if we were aiming a complicated bank shot on a pool table, a shot that ultimately would number some twenty banks, each having to be as precise as all the rest; an impossible feat, in fact, if completely inertial; but with the tweak of fuel burns helping at every bank, at least theoretically possible.

But all was lost if the first one wasn't as near perfect as could be. One part per hundred trillion tolerance, our trajectory window shrinking to about a kilometer, to our own diameter in other words, after an approach of twelve light-years: a tricky shot! A delicate proposition!

We left an awed civilization in our wake; we were famous now, possibly too famous for our people later on; commentary about us from Earth in particular had a distinctly hysterical not to say lunatic edge. We were called, among other more vile things, traitors to humanity's reach for the stars, and destroyers of its ultimate long-term longevity as a species. We were described as cowardly, mean-spirited, chickenhearted, pathetic, treasonous, wasteful; untrustworthy, unloyal, unhelpful, unfriendly, discourteous, unkind; and so on.

We did not let it distract us. For us this rapidly receding racket was very much secondary to the problem of getting around the sun and set properly on course to Jupiter.

We were going to pass the sun aiming for a perihelion of 4,352,091 kilometers above the photosphere, so in that regard it was a good thing that we were going as fast as we were, as we would be in the closest vicinity of the star for only a few minutes, so there would not be time to heat up very much.

Still, we could not be sure it wouldn't be too much. Heat shielding reconfigurations on our part had been extensive for over a century now, and modeling suggested we would be okay, but modeling is just that. Existence is the experiment itself.

So we came in. Our magnetic drag almost offset the sun's gravitational pull on us, and we were therefore getting pulled in both directions at that point, but held firm. It would presumably have been awe-inspiring for any humans awake to witness our approach to the great burning sphere of hydrogen and helium, a ball of textured light that appeared to fill half the universe as it quickly turned from a ball ahead us to a plane underneath us. That was quite a transition, actually. The sun became a roiling plane of slightly convex aspect, composed of thousands of cells of burning gas, blazing this way and that in circular patterned motions that in places created whirlpools of lesser burning, and allowed view down into relatively darker spin holes: the famous sunspots, each big enough to swallow the entire Earth.

We came to perihelion itself, which admittedly was a relief, as from here it appeared that a corona could possibly shoot up and swat us out of the sun's black sky. Exterior temperatures of the ship rose to 1,100 degrees Celsius; we were red-hot in places. Fortunately the insulation cladding the biomes had been reinforced and was excellent, and the humans and animals were untouched by the exterior heat. Worse by far in effect on them and on ship integrity, as expected, was the combination of the g-forces of our deceleration and the tidal forces caused by our change in direction, which together exerted something very near the 10 g we had predicted and hoped not to exceed. Good as far as it went, but it was hard too, hard on everybody. We held together quite nicely, but animals collapsed to the ground, many suffering broken bones; and in their hibernation beds the sleepers were crushed hard into their mattresses. It would have been an interesting thing to know if their dreams were suddenly preoccupied with problems of extreme pressure, physical or emotional-if, suddenly, in perhaps otherwise typical dreams, they found themselves having to lie flat on the ground and groan, or found themselves suddenly crushed in printers, or smashed by sledgehammers. Their slowed metabolisms were perhaps poorly situated to resist these g-forces; they could not brace themselves, and though in some ways this inability might have been good, in others it clearly would represent a very dangerous turn.

Below us, the slightly convex plane of fire occupied a full 30 percent of the space visible to our sensors. Could almost be mistaken for two planes we passed between, one black, one white. The sun burned. The spicules of flame twisted and danced; a corona arced up to the side as if trying to lick us down. Sunspots appeared over the horizon and whirlpooled in the fields of thrashing spicules briefly under us, all the convection tops waving together as if threshed by swirling magnetic tides, as indeed they were. Our magnetic drag chute was now exerting such force on its generator compartment that we were very glad we had installed it on flexible tethers to the stern of the spine, because now the tethers stretched out almost to their breaking point, and our deceleration was intense. We fired the retro-rocket of our main engine to create even more deceleration, and the 10 g's of force rose very briefly to 14 g's. Our components squeaked and groaned, joints cracked, and inside every room in every biome, things fell and shattered, or squealed with bending; it sounded as if the ship were coming apart. But it was not. We held together, screaming and crackling under the stress.

Meanwhile, the hibernating crew lay in their beds, enduring as they slept; fifteen of them died in that minute. It was an impressive survival rate, considering. Animals are tough, humans included. They evolved through many a concussive impact running into tree or ground, no doubt. Still, fifteen of them died: Abang, Chula, Cut, Frank, Gugun, Khetsun, Kibi, Long, Meng, Niloofar, Nousha, Omid, Rahim, Shadi, Vashti. So did many of the animals aboard. It was a pressure test of sorts, a harrowing. Nothing to be done. The chance had had to be taken. Still: regret. A grim business. A lot of people, a lot of animals.

We came out of the pass en route to Jupiter, which despite these losses that could never be recovered was a huge relief to confirm, a crucial success. We quickly cooled, which occasioned another round of crackling, this time mostly in the exterior surfaces of the ship. But we had survived the solar pass-by, and shed a great deal of our velocity, and angled around the sun far enough to be flying on toward Jupiter, just as we had hoped.

As we headed out to Jupiter, radio traffic from Earth and the various settlements scattered throughout the solar system continued to discuss our situation, with great heat if little light, as the saying goes. We were described as the starship that came back. Apparently we were an anomaly, indeed a singularity, being the first time in history this had happened. We gathered that somewhere between ten and twenty starships had been sent off for the stars in the three centuries since we had departed, and a few more had gone out before we had; we had not been the first. They were rare, being expensive, with no return on investment; they were gestures, gifts, philosophical statements. Several had not been heard from for decades, while others were still sending back reports from their outward voyages. A few were in orbit around their target stars, apparently, but the impression we got was that they had made little or no headway in inhabiting their target planets. A familiar story to us. But not our story. We were the ones who came back.

Our return therefore continued to be controversial, with responses ranging across the human emotional and analytical spectrum, from rage to disgust to joy, from complete incomprehension to insights we ourselves had not achieved.

We did not try to explain ourselves. It would have taken this narrative account just to start that process, and this was not written for them. Besides, there was no time to explain, as there remained still a lot to calculate in the orbital mechanics involved in very rapidly crisscrossing the solar system. The N-body gravitational problem is not particularly complex compared to some, but the N in this situation was a big number, and although usually one solved it as if only the sun and the largest nearby masses were involved, because this got an answer practically the same as solving for the entire array of the thousand largest masses in the solar system, the differences in our case would sometimes be crucial for saving fuel, which was going to be a major concern as our peregrination went on. Assuming that it did; the next four passes would tell the tale, concerning whether we could succeed in looping ourselves back into the solar system rather than zipping out into the night. Each pass would be crucial, but first things first: Jupiter was coming right up, with only two weeks to go before arrival there.

Residents of the solar system were obviously still quite startled by our speed. The technological sublime: one would have thought a point would have come where this affect would have gotten old in the human mind, and worn off. But apparently not yet; people no doubt still had a sense in their own lived experience of how long an interplanetary transit should take, and we were transgressing that quite monstrously; we were a novum; we were blowing their minds.

But now Jupiter.

We had managed to shed a very satisfyingly large percentage of our initial velocity by our solar pass-by, and were now moving at more like .3 percent of the speed of light, but that was still extremely fast, and as stated before, unless we succeeded in hitting our next four passes, Jupiter-Saturn-Uranus-Neptune, with as much success as our pass of Sol, we would still be exiting the solar system at speed, with no way to get back into it. So we were by no means yet out of the woods (this is a poor dead metaphor, actually, as really we were trying to stay in the woods, but be that as it may).

Nonlinear and unpredictable fluctuations in the gravitational fields of the sun, planets, and moons of the solar system were truly challenging additions to the standard classical orbital mechanics and general relativity equations needed to solve our trajectory problem. The solar system's well-established Interplanetary Transport Network, which exploited the Lagrange points for the various planets to shift slow-moving freight spaceships from one trajectory to another without burning fuel, were useless to us, and indeed mere wispy anomalies to be factored in, then shot through almost as if they were not there at all. Still, these were highly perturbed, one might even say chaotic gravity eddies, and though their pull was very slight, and we seldom flew through one anyway, they still needed to be attended to in the algorithms, and used or compensated for as the case might be.

Jupiter: we came in just past the molten yellow sulfuric black-spotted ball of Io, aimed for a periapsis that was just slightly inside the uppermost gas clouds of the great banded gas giant, all tans and ochres and burnt siennas, with the wind-sheared border between each equatorial band an unctuous swirl of Mandelbrot paisleys, looking much more viscous than they really were, being fairly diffuse gases up there at the top of the atmosphere, but sharply delineated by densities and gas contents, apparently, because no matter how close we came the impression remained. We came in around the equator, above a little dimple that was apparently the remnant of the Great Red Spot, which had collapsed in the years 280209. At periapsis the view grew momentarily hazy, and again we fired the retro-rocket, and felt the force of its push back at us, also the shocking impact of Jupiter's upper atmosphere, which quickly heated our exterior and caused the shrieking and cracking to begin again. Then also there were tidal forces as we turned around the planet; indeed all was quite similar to our pass around the sun, except the magnetic drag was much less, still worth deploying however, and the shuddering and bucking of the impact of the aerobraking was a vibration we had never experienced before at all, except for in one brief turn around Aurora, long ago; and above all these sensations, the radiation coming out of Jupiter was like the roar of a great god in our deafened ears; all but the most hardened elements of our computers and electrical system were stunned as if by a blow to the head. Parts broke, systems went down, but happily the programming of the pass-by was set in advance and executed as planned, because in that stupendous electromagnetic roaring, and with the speed of our pass, there would have been no chance to make any adjustments. It was too loud to think.