Saturday, April 30, 2016

Stages in the Star Travel Era

Star travel is most likely after an alien civilization reaches asymptotic technology (AT). Some premature attempts can be made, but the alien civilization is likely to understand the history of technology development long before any star travel activity can be started, and would recognize that almost all aspects of technology would be useful in developing means for star travel. There is very likely not going to be any driving need for star travel until this short period of technology development is passed, so likely even if some alien civilization thought it might be a good idea to try it early on, by the time the preparations were completed, so would AT.

Asymptotic technology does not mean that all engineering for every conceivable project has been done, just that all scientific knowledge is complete, and the basics of engineering using all of it has been figured out. Engineering is likely to be done by AI in the AT phase of an alien civilization, so it will not take a long time to design a starship. Preparing it will take a long time, even with AI doing the logistics.

Before star ship design is done, a tremendous amount of scientific learning will have been done that will be relevant to the star ship design. Interplanetary exploration and mining will provide much of it. Reliability is one aspect. Building spaceships to explore the home solar system will provide reliability information for the relatively short term of solar system trips, perhaps dozens or even hundreds of year in duration. Orbital stations that endure for long periods will also give information on centuries of reliability problems in space. Propulsors and energy sources are another aspect that will be developed for solar system travel, as will longer range communication systems. The development of AI ship commanders will contribute. Intellos that are self-regenerating and tolerant of space conditions, such as weightlessness and radiation, for space ship operations will be another major contributor.

Extending the reliability information to thousand year flights can either be done by putting off star travel to later in the AT era. With possible levels of recycling of materials of all kinds, and the development of fusion power sources should ensure that the alien civilization will endure far longer than this.

The one thing that is not likely to be done in full scope is the end stage of an interstellar voyage. Other posts have discussed the requirements for this phase. Braking into an appropriate orbit and sending down landers will be a piece of cake at this stage. Assessment of the state of the planet will be the troublesome part.

In seems absolutely inevitable that any alien civilization planning an interstellar voyage would build giant spaceborne telescopes and investigate the destination planet in great detail. As posted elsewhere, a continental map would exist, along with a large amount of information on the planet’s overall chemistry. The biology would not be detectable, only to the stage that there were no large detectable cities so no far-developed alien civilizations there. There is such a short period of civilizational development, a few thousand years or so, when there would be undetectable civilizations there, compared to the billions of years that planets last or that it takes life to get to that stage, that the probability of an alien star ship arriving when the planet when there was an undetected alien civilization is vanishingly small. The alien civilization sending the starship could even extend their observation time prior to launching the ship to cut this probability down further.

Thus, there are four phases in the star travel era. One might be called the destination search phase, where large observatories in the far reaches of the home solar system are used to scan nearby galactic space for candidates. By the way, one of the things that AT will develop in the alien civilization is patience. Taking whatever time necessary to find candidate destinations and scan them for a long time would be the only way the alien civilization would proceed. Is it possible that some peril is looming in a short period that would cause them to have to shift to fast star travel? Probably not, as short term ones they can deal with, and long term ones give them enough time to prepare properly.

A second phase would be the technology and reliability phase. This would overlap the destination search phase somewhat, but that phase is likely to conclude its main operations in a short time compared to the duration of a star trip. This involves the engineering of prototypes of the star ship and using it to travel through the solar system in shakeout mode. Because of the huge expense of the star ship project, there would be extreme measures of failure mode research, to find out what might cause the trip to fail, and then engineer solutions to the failure modes. Failure mode research as we know it now on Earth involves much preliminary work, then component level prototyping and failure mode research, followed by partial scale prototyping and failure mode research, then by full-scale prototyping and failure mode research, with failure mode work involving both long-term operations and also extreme event operations, so that both types of failure can be understood and accommodated. By the end of this era, a prototype star ship will be orbiting somewhere in the solar system. Think of centuries of duration.

During this phase the large observatories are not sitting idle. There would likely be a reassessment of the conditions in interstellar space, so that the density of different sized particles and elemental densities in different quadrants of interstellar space would be more exactly measured. Remember, this is the ‘asymptotic’ part of asymptotic technology.

In the third phase, operational testing would come next, with the AI commander of the star ship taking it from one planet or satellite to another, going through whatever portion of the actual operations at the destination planet that can be done. Again, think of centuries. Also think of several stages of ships being built, with problems found in earlier versions being solved in later versions.

The last phase involves the actual trip. After several centuries to build the ship and test it every possible way, it is launched. Traveling out, say, 250 light years at 0.01 c would take 25 thousand years. This dwarfs the time done in preparation, and so it is clear to see how difficult the reliability phase of the engineering of the ship would be. With the proper population controls, recycling measures, and interplanetary resource exploitation, the alien civilization could certainly survive to hear results coming back from their new colony.

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