Saturday, August 29, 2015

Emigration Ships for Category Two Aliens

Category two aliens are those who do not like star travel, maybe it makes them seasick, and they refuse to do any until they absolutely have to, like when their planet is about to be destroyed or some such fate. They emigrate to some other really nice planet, where they set down roots and enjoy their pleasant lives, at least until that planet has a big problem.

There are two ways to do this emigration. One is to send some alien citizens there to get things going, and then reinforce them as much as necessary, by sending other starships after the first. This is what we called emigrant trains in a previous blog, where the possibility of detecting them was first raised. Nosecone heating doesn’t work, except if they fly through a Bok globule, which they shouldn’t.

Not all the aliens would emigrate, as the stellar problem or the planetary problem or the supernova problem or whatever it was that was going to ruin their planet for living there would all be predictable. They would have a neat way to emigrate, because they would have, as part of their development of asymptotic technology, developed long ago, have figured out how to do gestation of young aliens mechanically, rather than biologically. Actually, they could have developed good techniques for external gestation involving a combination of biological and physical tools. The point is that gestation of young aliens is decoupled from the presence of other aliens. They grow the next generation industrially, so to speak, rather than having whatever gender of aliens (if there was more than one, they might be hermaphrodites) used to give birth, lay eggs, bud, or whatever they used to do.

This decoupling means they just have to get the gestation machines over to the new colony, and turn them on. Of course, building the first city would be necessary, as well as exterminating the native flora and fauna if they didn’t want to adopt them. Starting a power plant and some mines to replace recycling losses would also be necessary, as well as developing a source of fuel for the power plant. Getting a spaceport set up is also clearly in the cards for them, unless they all plan to parachute down. In short, there is a lot to do there, but only a small fraction of the population needs to go. Obviously, they would have to develop a gigantic engineering plan, figuring out what to do first to minimize the amount of shipping from the old world they would need. But the main point is, that new aliens are all gestated on the new world, and the population gets gradually built up there. Back on the old planet, citizens live out the natural course of their lives, fifty years, a hundred years, five hundred years, or whatever. Emigration of the civilization is done without emigration of the population.

The second alternative is to do everything robotically, and only send a ship with some really spectacular artificial intelligence that could handle everything necessary to replicate the alien civilization on the new planet. The same idea of emigration of the civilization being unconnected with the emigration of the population holds.

How would the aliens decide between alternative one and alternative two? Flipping a coin is probably not the way super intelligent aliens, with master computing capability available at their fingertips, would do it. Likely they would do a cost-benefit analysis for emigration, which would be very different from a cost-benefit analysis for colonization. Category zero aliens are doing the latter, and category two’s are doing the former.

The cost benefit analysis would take into account the costs of the starships needed in the two alternatives, the time needed as compared to how much time they have before the basalt flood pops to the surface or whatever else what going to ruin the planet, how much of the home world resources would be required, and certainly other factors. Reliabiity would not be a factor, as they would build in backups, just as we do, so that reliability was high, and met whatever level of risk they were willing to take. It might just be that reliability, in the guise of taking care of unplanned events, is much higher with a ship with citizens on board, or it might be the other way around.

Suppose they chose alternative one, the emigration ship choice. What would an emigration ship look like? Here on Earth we have speculated a great deal about this, and there are interesting ideas in the areas of propulsion, power sources, artificial gravity, navigation, recycling, hotel requirements, hibernation if desired, shell hardness, and all the other things somebody building a starship would want to know about. There are even conferences on the subject.

Are any of these areas show-stoppers? In other words, is it impossible to design some component of the ship so that the requirements of carrying a crew over many light years can be met? One interesting area is artificial gravity. There have been some negative consequences found for humans living in zero gravity situations, and who knows, maybe aliens would also suffer from some. Or possibly, octopus people would not care one way or another. A civilization which lived underwater, if such things are possible, would just have to worry about not having any leaks. Mass requirements would be greatly different. Buoyancy reduces the effect of gravity and acceleration so much these octopus guys would hardly notice the launch. They would be looking for different worlds than land animal civilizations would, anyway.

For artificial gravity, a revolving wheel is the usual recommendation. Perhaps long-term revolving is bad for anything with a strong sense of gravitational direction, and then the question arises of how much awake time would be necessary if hibernation gets figured out for them. Since they are omniscient in the proper way, they would know if their species could handle living in a freezer for years. The other alternative is to keep propulsion going for a long part of the voyage, which provides some amount of gravity during both acceleration and deceleration. Using propulsion at a low level for the long term means that the average speed might be lower and the duration longer. Power requirements would be different as well.

It would be a foolish choice, and even we know this, to build the ship on their home planet. Building it as far out of the gravity well of the planet and its star saves on everything. The logistics of getting the components and supplies out to the distant construction orbit would have to be balanced against the difference in the costs of building the ship. The cost-benefit analysis of course includes all construction costs.

The first ship to arrive at the destination planet has to arrange the logistics of getting all necessary supplies and crew or passengers down to the surface of the planet. Perhaps the first ship would go into a planetary orbit around the star, and detach some smaller vessel to drop into planetary orbit, which would in turn have something smaller to land on the surface safely and securely. How large a load would have to be delivered?

The aliens’ cost benefit analysis cannot be done until they have determined what mass they need to put onto the new planet on their first trip there. This mass is determined by exactly how they plan to proceed. Materials which are not delivered must be mined on the planet. They can’t figure this out until they have determined the ease of access to minerals of various kinds.

Some alternatives are now apparent. Do they want to make a huge ship, capable of long endurance in orbit, with multiple third stage vessels going down to the surface with robotic mineral exploration probes, later to be followed by vessels with citizens? Or do they want to have the first ship just do exploration tasks, and drop citizens down from the second or later ships in the emigration train? It will be interesting to discuss some of these details later. If we can get an idea of which is better, lots of smaller ships or a few huge monster ships, it will make the job of detecting them easier. As noted in another blog, if the galaxy has as many populated planets as some calculations indicate, there will be emigration trains running in the galaxy much of the time, provided there are destination planets available.

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