“I already am. There’s a cart here that can carry you to your ferry. Must inform you that the ferry is now just one room in a more streamlined version of the ship.”
“More streamlined?”
“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.”