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How Will Humans Fly to the Stars?

by Andreas Hein

The immense problems of time, distance and life support invariably mean that when we talk about an interstellar mission, we talk about robotics. But the imaginative team at Icarus Interstellar, which is now setting up projects on everything from beamed lightsails (Project Forward) to pulse propulsion engines (Project Helios), has pushed into the biggest what-if of all, the question of manned missions. And as project leader Andreas Hein reminds us in the following article, a variety of approaches have been suggested for this over the years from which a new concept study can grow.

Andreas Hein received his master’s degree in aerospace engineering at the Technische Universität München, and is doing his PhD at the same university in the area of space systems engineering at the Institute of Astronautics. He has participated in several mission studies: a lunar gravity measurement mission by EADS and a cubesat mission analysis. During his internship at ESA-ESTEC, he participated in the joint ESA/industry lunar architecture study of the human spaceflight division, applying different systems engineering methodologies such as stakeholder analysis. Andreas is currently supervising a course on concurrent engineering of space systems at the Institute of Astronautics whose objective is to design an Earth observation mission. His particular interest is in the early phases of systems design, which he lists as requirements engineering, functional analysis, concept design/trade offs.

News of recently discovered exoplanets reaches us almost weekly and it seems only a matter of time until an “Earth 2.0” is found out there. If this happens, is there any possibility for humans to travel to this planet with today’s or foreseeable technologies? This is the main question Project Hyperion deals with.

Project Hyperion is a research project whose main purpose is to assess the feasibility of crewed interstellar flight with current or near-future technologies.

I will first give a brief overview of existing concepts for crewed interstellar flight and then dwell on challenges apart from crossing the distance between the stars.

Image: Andreas Hein (left) and Alan Bond, designer of the Bond/Martin World Ship concept, at the headquarters of the British Interplanetary Society. Credit: A. Hein.

Ideas for the Long Haul

The primary purpose of crewed interstellar flight is the long-term colonization of an exosolar system. What are the concepts that exist today to achieve this goal? The most well-known concept was introduced by Robert Forward in 1984 [1], who discusses the feasibility of a crewed trip to the nearest stars by a laser-pushed sail. Another concept is the fusion-propelled “colony ship” by Gregory Matloff, published in 1976 [2] and the “world ship” concept of Alan Bond and Anthony Martin [3]. A recent analysis for an antimatter rocket was conducted by Robert Frisbee in [4]. Most of the existing “near-term” concepts can be put into four categories, based on the mode of crew transportation:

  • Crew lives on the spacecraft: world ships, colony ships [2-5]
  • Crew is in suspended animation or hibernates [6]
  • Crew is transported as embryos or single cells [7]
  • Crew is transported digitally [8]

We still know too little about each of these concepts. Nevertheless, some educated guesses can be made: From a) to d) an increasing level of technological sophistication is required in order to achieve the mission. On the other hand, the resources needed for transporting the crew decrease at the same time, which enables faster travel. Think of a lorry being slower than a Ferrari although they have the same horsepower. A world or colony ship is a massive spacecraft, several tens of miles-long. The crew lives and dies over generations on these small worlds, crossing the comic ocean between the stars taking centuries.

Image: A worldship dwarfs the imagination, offering a habitat for humans over the course of generations on a long, slow voyage to the stars. Credit: Adrian Mann.

A suspended animation / hibernation ship is still large but does not require a habitat as large as a world ship: most of time the crew “sleeps” during the trip like in the introductory sequence of the movie “Avatar”. However, some kind of habitat is probably still required for periodical “awakenings”. An embryo or single cell ship will likely have a payload the size of a house as no habitat is required and a digital crew spacecraft payload might have the size of a small car or even smaller.

Each concept is challenging in its own way: It is in principle possible to build a world ship or colony ship today, given the resources. However, how to design a habitat that enables human survival and comfort for centuries? This has analogies to people living on an island cut-off from the rest of the world. How will culture and technology develop under such conditions? Will people live like in the Stone-Age when they arrive at the target star system? How many people should be sent to maintain at least a certain level of cultural and technological diversity? How is the spacecraft maintained over centuries?

The feasibility of using a spacecraft with a crew in suspended animation or hibernation depends on the applicability of these concepts to humans. Whether or not it is possible to sustain a crew in this state for decades or even centuries is still an open question.

An embryo or single cell ship needs an approach to raise and educate them at the target system. Methods like android parenting have been mentioned in the literature. Furthermore, sophisticated automatic manufacturing is required to construct a shelter and to provide nourishment on the target planet. These are all technologies that are not available today. Whether or not a crew can be “resurrected” on the basis of digital data in the target system is an open question. If this becomes possible one day, this technology will not only make this special form of interstellar travel possible but will have a profound impact on our life on Earth.

Besides these technological challenges for each concept, different ethical questions have to be addressed as we are dealing with decisions that have far reaching consequences for the crew sent out to the stars and the ones that are yet unborn.

Building the Star Colony

We have now briefly covered the potential approaches for crossing the gap between the stars. But what happens once the crew arrives at the target star system?

Most of the scientific literature focuses on the trip between the stars. However, the establishment of a colony within the target star system is a neglected, but vital part for planning such a mission [9]. We often assume that a habitable exoplanet is very similar to Earth and human life is possible on its surface. But there are myriads of potential obstacles to colonizing such a planet: An ecosystem that does not provide edible food and water, diseases to which the human immune system can not adopt adequately, toxic substances etc.

It is difficult to say whether it is possible to anticipate these difficulties in advance as many issues will remain undiscovered, even after an exploration with precursor probes. Alternative approaches like terraforming and building artificial colonies in space were also considered [2, 9]. Terraforming aims at changing a planet in a way that human life is possible on its surface for extended periods of time. Artificial colonies might be the last fall-back-option, in case human life is not sustainable on a planetary surface. The concept of large space colonies has been proposed by the physicist Gerard O’Neill in the 70s as a mode of human existence in the future [10]. This might ultimately make colonization of another star system independent of the discovery of a habitable exoplanet. However, the immense difficulties associated with both approaches are difficult to anticipate today.

Image: The ISV Venture Star from James Cameron’s film Avatar. Credit: Ben Procter.

Most of the publications mentioned in this article have limited detail and are restricted to rough outlines and estimates without detailed engineering assessments. Think of the difference between a painter’s pencil sketch to prepare for a painting and the meticulous work that has to be put in to flesh out all the details on the canvas. Currently, only rough sketches exist.

With Project Hyperion we want to get from the sketch to the real painting! It is our conviction that today most of the required feasibility analysis for a crewed interstellar spacecraft can be done with current knowledge. Some readers will certainly think: “Ok, this is a nice exercise but won’t it take several centuries to realize such a mission? So why think about this today?” I agree that it is still a long time to go to see the first humans heading to the stars. However, we humans exist on Earth as a species for about 200,000 years. If one thousand years are one meter, this is a distance of about 200 meters, more than twice the length of a football field. If it takes about 300 years to send out the first humans to the stars, on this scale, this is about 30 cm. How insignificant in comparison to the distance in time we already traveled as a species and what a magnificent chance to take the first steps towards this goal today.

References

[1] Forward, R.L., “Roundtrip Interstellar Travel Using Laser-Pushed Lightsails”, Journal of Spacecraft and Rockets, Vol.21, No.2, March-April 1984.

[2] Matloff, G.L., “Utilization of O’Neill’s Model I Lagrange Point Colony as an Interstellar Ark”, Journal of the British Interplanetary Society, Vol. 29, pp. 775-785, 1976.

[3] Bond, A., Martin, A.R., “World Ships – An Assessment of the Engineering Feasibility”, Journal of the British Interplanetary Society, Vol. 37, pp. 254-266, 1984.

[4] Frisbee, R.H., “Limits of Interstellar Flight Technology”, Chapter 2 in Frontiers of Propulsion Science, ed. by Millis, M. and E. W. Davis, Progress in Astronautics and Aeronautics, 2009.

[5] http://enzmannstarship.com/

[6] Various articles on hibernation in JBIS, Vol. 59, pp.81-144.

[7] Crowl, A., Hunt, J., Hein, A., “How an Embryo Space Colonization (ESC) Mission Solves the Time-Distance Problem”, presentation at the 100 Year Starship Symposium, October 2011, Orlando, USA

[8] Tipler, F., The Physics of Immortality, Chapter 2, Doubleday, New York, 1994.

[9] Matloff, G.L., Mallove, E.F., “The First Interstellar Colonization Mission”, Journal of the British Interplanetary Society, Vol. 33, pp. 84-88, 1980.

[10] O’Neill, G.K., “The Colonisation of Space”, Physics Today, 27, No. 9, 32-40, September 1974.

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Comments on this entry are closed.

  • Tony P April 17, 2012, 9:37

    Great article. And thank you for the extensive reference list. It will make for some great reading this week.

  • ljk April 17, 2012, 10:34

    As always humans are either the key or the obstacle to such projects as this. I agree that unless there is some urgent even dire need to send lots of humans on a multigenerational journey to the stars, we should avoid this as our means of reaching the rest of the galaxy.

    Why? Because if by the time we are able and willing to build worldships and humans have remained largely unchanged either through genetic or technological manipulation, the thought of having to spend ones entire life with the same group of people – who except for the last generation know that their entire lives will be primarily to make the next generation for a far future destination – now strikes me as making the scenario in Orphans of the Sky look tame.

    The folks who used to work on The Ultimate Project, a cylindrical Worldship one mile long with one million people aboard that would take 500 years just to build and launch, said that a written constitution would keep the human crew civilized during the estimated ten thousand year journey to an Earthlike alien planet.

    Seeing as one anthropologist said that once a tribe of people get beyond 100 in number that dictatorships tend to arise, not to mention all the rest of our ancient baggage rearing its head regardless of the situation, I honestly have to wonder how a piece of paper would keep such a society intact without having to institute some draconian measures. Then again, plenty of people followed Hitler and Stalin and a bunch of other totalitarian rules willingly and without question. And just ask most religions about their groupies, which is probably about the only way short of drugs or brain surgery that most humans will probably remain together as an organized society under such conditions.

    I know there are people here who do not like to read cynicism when it comes to space (except for the concept of ETI, then it is cool and trendy), but as our reality, experience, and knowledge about what is technologically capable by current and near future humanity has certainly improved since Heinlein came out with his still classic novel over seventy years ago, the human factor seems more of a burden than a benefit when it comes to starships of just about any flavor. Remember that when von Braun designed his manned lunar ships in the 1950s, he anticipated about 75 men (and I mean men) in each spaceship doing tasks that were taken over by computers and other technology just a decade or two later. Same will be the case and even moreso with starships when we finally get around to building them.

    Elsewhere in CD I had written this mantra I created: Robots are for exploring space, humans are for colonizing the same. Both will need and benefit from each other off and on, but in the end that will be the main purpose of both types. And as for humans colonizing the galaxy and beyond, if they do not elect to stay in their Worldship (assuming it is very roomy with lots of variety and people like a terrestrial city), they will have to terraform any worlds they want to settle, as you know there will not be a copy of Earth out there ala Star Trek and the alien planet will have to be remade – again assuming that humans by then will be like us, which I doubt.

    While I can see some really rich cult or similar group wanting to escape Earth via such a manner (read the history of Biosphere 2 as a real-world example, and maybe even Heaven’s Gate; plus Frank Drake relayed a very funny story about meeting Timothy Leary while the latter was in jail to discuss how to build a starship so he and his followers could move to a less fuzz-infested corner of the Milky Way), the only other “practical” way I see a Worldship happening is if Earth is in danger – and by then it may be too late to do anything about it. Of course also by then we should have colonies throughout the Sol system, so not every human will be in one cosmic basket anyway.

    By the way – does anyone know whatever happened to The Ultimate Project? They seem to have fallen off the radar. Pity because they were already laying down the framework that the 100 Year Starship is just starting on.

  • ljk April 17, 2012, 10:42

    And oh yes, about those potential Earthlike worlds out there: Even if they are not duplicates of our planet the fact that they are similar to us means that there will likely be life of some kind. So do we just move in ala Avatar and declare manifest destiny, even if they are no smarter than, say, bears, or do we literally make our own worlds ala terraforming and harm no native creatures in the process?

    This is an issue that surprisingly does not get addressed very much except for tokenly bringing up the Prime Directive from Star Trek, which only applies to cultures that have not invented warp drive yet, which is incredibly narrow and humanocentric in focus. Then again, Star Trek always liked to assume that just about everyone in the galaxy looks and acts like us anyway, which I sincerely doubt is the case in our reality.

    And let us hope that any ETI out there with a Worldship has already considered the options and the ethics should they decide to appear over Earth anytime soon.

  • Tarmen April 17, 2012, 14:14

    I believe humans will have to take the example of Nature. ie. Send all possible “species” of interstellar colonial ships. Try all of them, knowing full well that most or all of them will fail in their quest to reproduce in this Springtime of humanity. Perhaps each nation will take a different approach. Probably, some of our shots-in-the-dark will live and reproduce Earth-life. And if our civilization fails, maybe there will be another “Spring” in another century or millenium in the future.
    Or maybe the dolphins will succeed in June of 3,441,345 AD !!

  • jkittle April 17, 2012, 15:13

    the time it takes to travel to the stars- compared to the existance of our human subspecies. Nicely done and very poetic
    This is why we need to apply steady effort . We are part of something bigger, perhaps.
    I still think the possibility of finding planet ready to move into and set our tents and fire up the grill is pretty remote, even in the whole galaxy. Therefore we are left with teraforming and space colonies… bet we can do that in our solar system in preparation to “galactic expansion”

  • ljk April 17, 2012, 15:51

    Tony P, when going through your new reading list from here, step carefully when encountering Frank Tipler’s book, whose full title is:

    The Physics of Immortality: Modern Cosmology, God and the Resurrection of the Dead

    Tipler discusses the Omega Point, which he says is where everything and everyone in the Universe will end up one day way down the road.

    French Jesuit Pierre Teilhard de Chardin had him beat on this idea anyway:

    http://en.wikipedia.org/wiki/Omega_Point

    More about Tipler here:

    http://blogs.discovermagazine.com/cosmicvariance/2009/01/05/the-varieties-of-crackpot-experience/

    Tipler was once famous (or infamous depending on your point of view) for declaring that since von Neumann machines did not populate the entire Universe that therefore ETI did not exist, otherwise we would be overrun by these alien duplicators by now.

    I distinctly recall Sky & Telescope magazine running his article on this subject circa 1980, which I found rather interesting at the time, because back in the day it was not quite as fashionable as it is now to have pieces on alien life in such publications. I kept wondering why they chose Tipler’s article and perspective over many other possibilities.

  • tesh April 17, 2012, 16:14

    @ ljk
    “Why? Because if by the time we are able and willing to build worldships and humans have remained largely unchanged either through genetic or technological manipulation, the thought of having to spend ones entire life with the same group of people – who except for the last generation know that their entire lives will be primarily to make the next generation for a far future destination – now strikes me as making the scenario in Orphans of the Sky look tame.”

    First, every generation exists and has existed for making and shaping and using the next. Second, most humans usually spend most of their lives both knowing and hanging out with a tiny fraction of their fellow humans.

    I don’t think these are show stoppers. Send enough and some will make it…

  • Michael April 17, 2012, 16:20

    There is no reason why we could not send a Daedalus type probe with people on it (couples) although long term radiation could be a real risk from space and the engines. We would have to halt or greatly slow down of the rate of aging and health issues due to the loss of gravity. Virtual reality would be needed as well. Hibernation and genetics advances would be needed, they could be linked. Each couple could take turns sleeping and been awake, say sleep for 20 years and be awake for 1 year. News from earth could be transmitted at the speed of light and any technology advances or issues could be sent via transmission. As fuel is used up the tanks could be used for extra space.

  • Marc G Millis April 17, 2012, 16:40

    These are good questions. I would like to emphasize that many of the questions about far-future colony ships, when finally answered, will help ALL humanity, not just the space travelers!

    Consider, for example, if we already had closed-loop-life-support (a necessity for colony ships). Those methods, applied to life on Earth, would greatly reduce waste. And from that technology we could finally calculate the actual population limit of Earth, rather than learning that limit the hard way, someday.

    Even ‘societal’ questions apply. Recall your last discussion about politics or religion. Heated, yes? In the context of today, these questions provoke emotionally-packed arguments.

    But for far-future colony ships, those discussions can proceed more rationally. For future citizens, instead of ourselves, we can frame our discussions of governance models (politics), finite resources, and cultural morals (including religion) in the scholarly quest for how to make life on a colony ship stable and rewarding. We have the luxury of dispensing with bad habits and unhealthy cultural conventions. In this ‘dispassionate’ science, we can examine the data about successes and failures of governance models, the positive and negative aspects of religion, and the raw nature of human behavior (sex, love, violence, compassion, corruption, collaboration) with less bias. We are free to face the ugly aspects of human behavior in a ‘compensating’ manner instead of just being repulsed. We can determine how to govern ourselves and provide rewarding lives. And after we determine all that in the context of colony ships… we can apply that wisdom to life on Earth.

    Interstellar flight is a human journey, even if we never get off this planet.

    Marc

  • Ole Burde April 17, 2012, 18:06

    Some people seem to believe it would be too hard for humans to live for generations in a starship without all the luxuries they enjoyed as kids themselves . . it would seem that THEY would NOT be the right kind of people to creew such a ship !
    My own favorite solution is that every crewmember will leave behind an identical twinbrother (or clone) . In that way each creewperson knows ,that children who could have been his own will be born on earth , even if gambling for the stars shold fail .

  • Rob Henry April 17, 2012, 19:49

    Marc G Mills, I thought a subtext implicit in your last comment was so important that I had to make it explicit. We probably have to bear the deficiencies of the political and governance structures that we inherit, but on a worldship we are free to optimise them by strictly analytic criteria.

    Could it even be true that it is the stay-at-homers that are more likely to eventually need rescue?

  • Alex Tolley April 17, 2012, 20:20

    Terraforming a planet will take about as long as we have been around a s species. It might make sense for robot probes to start teh process throughout the galaxy and then have planets waiting to be colonized. But evolution could still throw up surprises in these “earth” worlds.

    As regards the 4 options, why the implied mutual exclusivity? Suppose we can digitize minds and have these be the machine intelligences to raise the embryos, rather than the unobtainable (so far) AIs? I don’t expect current meat humans to make the journey, but possibly some gene-engineered/machine hybrid “human” might.

    For hopeful colonists, the question to ask is, “Is there any there, there?” Are there target worlds to colonize, or would we be much better off constructing them in solar space? Exploration I understand, but colonization…? Under domes…maybe.

  • Greg April 17, 2012, 21:02

    Sometimes I believe, possibly due to cheap easy communications of ideas, that solutions for interstellar travel have become stagnant. True there is a lot of merit in developing technologies based on Hyperion’s ideas, both for interstellar travel as well as for solving issues here on Earth, but it really isn’t anything new. Something like NIAC or BPP, something that we can get fresh ideas and possibly new perspectives.

  • amphiox April 17, 2012, 21:40

    If we have the technology to build worldships, we won’t need planets, except as sources of resources (and there are easier options here).

    A worldship is basically a de facto mobile colony, and it will be largely independent from the home planet, and will go where its citizens (I would not use the term crew anymore) want it to go, within the constraints placed by the need to replenish resources.

    If the worldships have the capacity to reproduce themselves, by building another worldship from resources harvested from space, and moving surplus population over, then the colonization of other star systems will most likely occur through a process of gradual diffusion, as an expanding cloud of self-replicating colonies move out from the solar system, seeking resources.

    Since worldship technology is easier to achieve than any of the others, I strongly suspect that the colonization of actual planets will not play a major role in humanity’s future, whether we colonize space or not.

  • Interstellar Bill April 17, 2012, 22:52

    It’s rather premature to study a voyage to a planet that most likely will be thousands of light years away. Even a generation ship would have to go 0.1c. Let’s face it, nobody’s ever doing that trip in one gulp.

    The ethical aspect of ‘colonizing’ such a biological treasure will grow over the next millenium from today’s abstract concern to a casus belli, due to its immense scientific & technological value. The first expedition to such a planet won’t be a lone one-off but the leading edge of a wave of Galactic Conquest. The last thing they’d do is ruin such a planet by colonizing it.

    No, interstellar travellers will be spacers already used to vacuum-homesteading. They’ll hate any planet with an atmosphere, which greatly complicates large-scale dismantlement. Their first love will be asteroids. They’ll bring all their foliage and wild-life with them.

    Students of interstellar travel must eschew the narrow confines of planetary chauvinism. Worrying about habitable planets is as pointless as Ponce de Leon’s quest for the Fountain of Youth, or de Soto’s for the Lost City of Cibola. Both of these mirage-chasers ignored the New World’s vast riches while bringing plagues and depopulation.

    Colonizing an Earth 2.0 would truly be a Cosmic Crime.
    Be a Spacer and stay out. It’s a Specimen-Extraction-Only zone.

  • Joy April 18, 2012, 1:49

    Good summary article and good comments.

    @Marc – I think I understand what you are saying and strongly disagree, if one intends the generation ship to be peopled by standard humans, all attempts at social engineering are doomed to eventual failure. Whatever the control system designed to avert social disaster, eventually some sociopath(s) will come along who is clever enough to subvert it without being recognized as a sociopath. Self interest, or even worse perverse malice, will find a way. Even more likely, if designed by the sort of social engineer knaves who have been tinkering with modern societies for the last century, your ship would be a fatally flawed dystopia from the outset and dead by the third generation.

    I would go for the full on eusocial model in a colony ship. Crew it with female clones, all same genome. Frozen clone embryos would keep allow the crew to renew itself. The “royal jelly” to produce and maintain the Captain/Queen/God-King (someone needs to be in charge, even though the crew is all identical) could be testosterone.

    When the Captain has to be replaced, you make another one. It doesn’t matter how the new Captain is chosen, designated from birth, consensus, secret ballot, lottery, trial by combat, any method works out the same. No privacy on the ship, open hive like living. That would be more of a naked mole rat nest than a human society, but quite stable, all that you need in a generation ship.

    Individual drones die, but the Crew genome is immortal. People will go on living due to inertia (hint, choose someone with a stable cheerful mood to clone, not a depressive or bipolar woman.). Genetically diverse frozen embryos (full of all the genetic types one wants for a frontier colony, but not on a generation ship) could be time-locked up in the “Do Not Open Until at Destination” vault.

  • ljk April 18, 2012, 8:36

    tesh said on April 17, 2012 at 16:14:

    “First, every generation exists and has existed for making and shaping and using the next. Second, most humans usually spend most of their lives both knowing and hanging out with a tiny fraction of their fellow humans.

    “I don’t think these are show stoppers. Send enough and some will make it…”

    The big difference between living on planet Earth or inside a giant spaceship is that for most of human history, we have thought that our world was IT, that there was nothing beyond and the gods and/or God put all their focus on our little species even though we were apparently so mortally beneath them (read Homer’s Illiad sometime to see how involved the ancient Greek gods got so wrapped up in one little war). The stars were just the lights of Heaven shining through some holes in the Big Dome over our heads. Those wandering sky lights were the gods going about their business and watching over us. A trip to anywhere took a long time and was fraught with danger. You know the phrase “To the ends of the Earth.”

    Oh sure, a few people have had inklings of what the Universe was really like starting a few thousand years ago, but most people straight through today view reality with their emotions, not through facts and logic. We may know intellectually that Earth is a pale blue dot in a Cosmos billions of years old and just as many light years wide, but that does not register for most humans, whose brains are still hardwired for hunting on the savannah and socially interacting with their tribe, not for realizing how far away the stars are. They’re only good for finding your way around at night and for adding to your tribe’s folklore.

    Given this thinking, we have more or less put up with living on Earth and hoping the next generations do better than us because we do not really see that we are on a Worldship that is eight thousand miles across going in an endless circle about a middle aged yellow dwarf star. Put unconditioned humans aboard a real starship, even a relatively big one say several miles across, and tell them that most will not live to see the destination star system, and let us see how far things get.

    And your statement about sending enough people so that some will make it. Do YOU want to be among the ones who likely don’t make it?

    Humans on starships are problematic. As I said before, maybe groups of a strong religious or political bent might be culturally strong enough to wait that long to get to another star (and presumably one with a nice planet there).

    We haven’t had individual humans stay in a space station for more than one year. And they always knew that Earth was just a few hundred miles below and they could be home in a matter of minutes. We have yet to build one single colony on the Moon or Mars and see how things go in a harsh environment where rescue is far, far away. This is why I want to see what happens to a local space colony first before we go popping folks in a big metal can on a journey thousands of years in the making. Saying that if we send enough of them a few should make it is a rather grim “experiment” you are placing on future human beings, don’t you think?

    Let us stick to machines. Most people here seem more comfortable with them any way and I think they will make much better interstellar explorers. Human colonizati0n of the stars is starting to seem rather archaic to me, along with an antique and misplaced sense of romanticism. This is not going to Antarctica, folks.

  • jkittle April 18, 2012, 9:10

    Life on the worldship is a small town. QED Humans are pre- adapted for worldship life, and in fact may cope better there than the average new yorker trying to live in the big city. The only constraint is to make the place roomy enough so that people can have some privacy. ” build them large and light” Even on earth the decision where to live and profession has huge impact on our children. At least the voyagers will not have to worry about being killed by atom bombs.. or a world war. ( well, maybe a very “small world” war!)

  • JohnHunt April 18, 2012, 11:36

    My perspective is that the lowest cost (i.e. low mass / low energy) interstellar missions will be launched well before a colony or worldship. I also think that if “bears” existed on a nearby exoplanet then complex life would have been common throughout the galaxy for a long time and at least some of them would have developed intelligence…but where are they?

    No, if we’re going to be the most productive, I think that we should focus on the low mass / low energy options.

  • tesh April 18, 2012, 12:13

    @ ljk
    “And your statement about sending enough people so that some will make it. Do YOU want to be among the ones who likely don’t make it?”

    This is irrelevant. Every ship sent out will have the best of intentions and be brimming with hope for a successful ending. I feel that these migratory journeys will be like those that have happened since the beginning of time (at least for humans). In the past humans have ventured in waves to the New world, the Polynesian migrations and probably many other destinations. In neirther case has the journey been risk free.

  • ljk April 18, 2012, 15:57

    Tesh, I still think there are better ways to explore and even spread ourselves out across the galaxy without having to stuff a bunch of people in a big tin can and hope for the best. My growing feeling on MGS (multigenerational starships) is that it is an antiquated and potentially fatal for all – not just risky – method of getting to another star system, whether just to stop by for resources or to stay put.

    I can just see something like a wealthy and megalomaniac cult leader (those descriptions of such a professional are probably all redundant) in an era when human civilization has extended itself into the Sol system dragging along his followers into deep space by such a method. Things could get ugly there in no time ala Jim Jones, David Koresh, or the less well known behind-the-scenes story of Biosphere 2, especially if the leader finds him or herself in a corner.

    This angle on interstellar travel is similar to how most humans still view ETI, as funny-looking (or near exact) versions of us, angels of salvation, or unholy monsters. The reality is probably much more diverse and interesting than that.

  • ljk April 18, 2012, 16:23

    tesh said on April 18, 2012 at 12:13:

    @ ljk
    “And your statement about sending enough people so that some will make it. Do YOU want to be among the ones who likely don’t make it?”

    “This is irrelevant. Every ship sent out will have the best of intentions and be brimming with hope for a successful ending. I feel that these migratory journeys will be like those that have happened since the beginning of time (at least for humans). In the past humans have ventured in waves to the New world, the Polynesian migrations and probably many other destinations. In neirther case has the journey been risk free.”

    While I am not foolish enough to think that any venture humans do in space or elsewhere will be perfectly safe, we have the advantage over our ancestors who crossed the seas in wooden vessels while thinking the world was flat and full of dragons of knowing far more about the realities of the sea of space and a true sense of what preventative measures to take than they ever did.

    It is one thing to be brave, bold, and adventurous. It is another thing to cling to old fashioned views and methods of machismo, sacrifice, and perceived human destinies. I am reminded of that line from the great 1960 film The Magnificent Seven about such attitudes: “Well, the graveyards are full of boys who were very young, and very proud.”

    That is where humanity is now in terms of the rest of the Universe and that is why I hesitate about using a Worldship full of people to see if we can get them to Alpha Centauri alive. Though I agree with Marc Millis that control type experiments along with much more experience and time in space could answer a number of questions about human capabilities and limits – though most anthropologists (and where are they on CD?) would probably agree with me that we are still third-order chimpanzees or thereabouts.

    In any event, as I like to say about METI, people will do what they want irregardless of what I think or say. Just putting my two cents out there.

  • ljk April 18, 2012, 16:43

    Just one more thought I must add about a slowboat Worldship: While I have little doubt that the first generation aboard will be practically dancing and shaking with joy over what they have accomplished and imagine what the future will bring for their distant children and the species in general – how might the next few generations feel when the are old enough to realize that their entire lives will be spent inside a big ship with the same people with literally nowhere else to go outside of suicide?

    Now they might be happy with the thought that their lives are predetermined for them and that they will be contributing to the success of the mission via their own children (but what happens to those who are unable to conceive through no fault of their own?). Or they might become very resentful and angry and endanger everyone’s lives. The reason that the Worldship in Orphans of the Sky went way off the original plan was due to a mutiny, which while left unexplained probably came about from a later generation group who wasn’t interested in being chained to the dictates of people long gone.

    As I said before, people will try things like this anyway, just as some will continue to send deliberate messages into the galaxy despite the perceived dangers. That is humanity as it has been for ages.

  • Warren April 18, 2012, 17:39

    @Amphiox
    “If we have the technology to build worldships, we won’t need planets, except as sources of resources (and there are easier options here). …A worldship is basically a de facto mobile colony, and it will be largely independent from the home planet…

    @interstellar Bill
    “No, interstellar travellers will be spacers already used to vacuum-homesteading. …..
    Students of interstellar travel must eschew the narrow confines of planetary chauvinism. Worrying about habitable planets is as pointless as Ponce de Leon’s quest for the Fountain of Youth, or de Soto’s for the Lost City of Cibola.” 

    Yes!  A being capable of interstellar travel must be well adapted to living there.  Any space traveler resembling a natural bipedal African primate will construct his own Tsoilkovsky/O’Neil settlement with its own little “sun” many years before he can make a trip to the stars.   It is hard to imagine that there will then be much interest in settling around other stars much less other habitable planets.  A few generations of practice and the artificial worlds will be as close to paradise as it is possible to get and natural stars and planets will be scary places.

    I think I read Adam Crowl say, someplace, that if aliens are nearby, that’s where they will be, in the Kuiper belt or the Oort cloud.  …bet he’s right.

  • Joy April 19, 2012, 1:00

    Re: worldships being like small towns

    This comment can only be appreciated by those who have actually lived in small towns. Small towns at their worst are only bearable in the sense that it is possible to leave by some means other than suicide. Stephen King knows small towns, “The Dome” should be required reading for worldship builders. I recently survived a very long 3.5 years in a remote town of 4,000 which the long suffering misfits called “scary Keri”. We had two child murders when I lived there, also suicides, rapes, assaults. Not to mention bullies, gossips, busybodies, etc. If I had been trapped on a worldship with those people, I would have suicided.

    Now I am in a somewhat different small town of 4,000. Life is better now. In part because in an hour I can be in a city of 1,400,000 and in 4 hours more can be in a distant city of 4,600,000. Plus I have the internet. This is more like living on a orbital colony close to a planet. I can’t imagine a worldship alone in deep space working out well at all.

    Again, the minimalist goal of a crewed generation ship should be to deliver a few working uteri (capable of incubating human colonists) to the destination. If genetically altered bonobos (with humanized uteri and wide pelvic outlets) could do the job, that would probably work better than a Homo sapiens crew.

  • Ronald April 19, 2012, 3:43

    Late joiner in this thread on worldships, space colonies etc. versus planets.

    Amphiox, Warren (“Worrying about habitable planets is as pointless as Ponce de Leon’s quest for the Fountain of Youth”).

    No, strongly disagree: as I have often argued on this website, planets are vastly cheaper per unit area per year than any space colony. It is really like the difference between finding a continent across the ocean or building platforms in the ocean.
    Besides, planets are also possess far far greater intrinsic long-term stability.

    Therefore, I think that space colonies will indeed be built, but either for very specific (space industrial, reasearch) purposes and/or for want of suitable planets within reach.
    Finally, we don’t even need perfectly habitable planets (though those would be very nice indeed): a civilization capable of building large space colonies and worldships will also be capable of terraforming, possibly in combination with genetically adapted species.
    Terrestrial and super-earth planets appear to be common, and even occurring, though more rarely, in the habitable zone. The real challenge is not utilizing the planets but getting there.

  • Eniac April 19, 2012, 9:52

    We are putting the cart before the horse. We cannot move humans to another star system without technology. We have to move the technology, and that is a lot harder than moving a few humans, be it as bodies or bits. The primary problem to be solved is how to produce an industrial seed: the minimum amount of machinery that will permit turning asteroids or planetary soil into more machinery, with or without human assistance. Only after this problem is solved can we consider ways to move humans on a one-way ticket, and it will be much easier with technology already established in the target system.

  • jkittle April 19, 2012, 10:09

    warren
    Right on!
    There tends to be lots of mass near stars and it is moving in regular orbits so… solar systems are going to be central nexus points for interstellar space civilizations. The total living space in icy bodies is likely to be MUCH larger than the rocky planets. Right nwo we are limited by power supplies but I do not think we will move out much past Mars anyway without improved powersources… at least fusion based on D-D reaction or barring that, finding lots of lithium ( for DT fusion ) or thorium out there.

    a couple generations in space and the inhabitants will have little interest in planets except to mine resources and for scientific study. may we can establish exbiotic zoos.
    This actually may be part of the answer to the Fermi paradox.. but why aren’t our asteroids inhabited by alien colonies? Maybe we have a system with too few low mass objects mass to merit much attention?
    by the way- Joy- I love the small town I grew up in. I had to leave for career, I did get to spend my time in Boston and Houston and LA but when I returned to live here, I found may happy people who never felt the need to leave.
    Maybe we need a small flotilla of ships heading in to any particular target, so that each can specialize and spread out the risks and offer some diversity of thought and environment .

  • tesh April 19, 2012, 13:23

    @ljk
    “While I am not foolish enough to think that any venture humans do in space or elsewhere will be perfectly safe, ***we have the advantage over our ancestors*** who crossed the seas in wooden vessels while thinking the world was flat and full of dragons of knowing far more about the realities of the sea of space and a true sense of what preventative measures to take than they ever did.”

    Those ancestors probably thought the same way of their ancestors. Perceived advantages and disadvantages we hold so highly will probably be far less consequential than we think. There are just too many unknowns.

    Migration from the Sol system is just as likely to be some disillusioned colonists in the outer Sol venturing into the deep unknown, in the wooden tub of their time and seeing if a better/less intrusive/away from everyone else/whatever life can he had somewhere far away, as it is for a colony ship to begin the process.

    Long and short of it is that migration off System Sol will be messy – just like every other migration.

    My feeling is there will never be a grand undertaking as long as there is such a thing as an economy and democracy – who can spare the dime?

    p.s. Even when Columbus knew that the earth was round, that there are likely no dragons and the sea was there to be conquered, he managed to bumped into an unexpected little piece of land that later came to be known as the Americas – who’d have thought…

  • tesh April 19, 2012, 14:34

    @ljk
    sorry did not see your previous post. We agree that migration off Sol system will be likely be messy. Many thousands, likely millions will die in the process. Whether we eventually succeed is up in the air.

    I don’t think we will wait for our ability to build huge ships, kilometres long, or the ability to travel instantaneously anywhere, to mature. There are too many curious/crazy/clever people about.

  • Ole Burde April 19, 2012, 15:25

    Many different ways here of relating to the human creew of a starship ,but some of them perhabs build on asumptions that are easily laid to rest .
    Here’s some of the most common :
    1 . The chance of finding an earthlike planet with an oxygenatmosphere produced by fotosyntesis , is so small that it would only happen statistcly thousands of lightyears away. …. Not true . Using only what is really known to us at present ,a reasonable guess would be that 1% of “relevant” stars could have such a planet , and that would translate to a distance of perhabs 80 LY .
    2. “Terraforming” of a planet similar to earth before life got started would take several millions of years….. Probably not true if life were intruduced in a controlled way , acording to a plan for maximum enviromental impact !
    Just imagine a few selected species of bacteria breeding exponentially without any natural predators , it would be fast and ugly !
    3 .Humans are not cabable of existing in small groups in stricly limited environments for many generations ,without all kinds of BAD things happening , such as cultural degeneration expressed here as “the second generation will not find any happyness or meaning to its life ”
    This will only be true if the crew is representative for mainstream Big-City behaviour patterns , which it ofcourse can not be . The crew wil have to be selected both geneticly and culturally , and long term experiments will have to be made in addition to the natural experiments that antropology has already documented in great variety .
    Small selfcontained human societys mostly break down when confronted with the alternative big-city way of living . Any relevant experiment would investgate the need for neutralizing this confrontation by layers of isolation.
    4 . Interstelar flight will only be possible AFTER the establishment of giant space colonies , because only such a colony will be capable of surviving by using spacematerials-only , when ariving at a less than Earthquality planet….this will not be true if the planet has resources which are easier to exploit than the ones in space . Even if the atmosphere are not perfect and the local life indigestible , it would still be alot simpler to survive by processing these almost-ready resources ,than to build a whole mini-planet from scratch by using only space rocks .
    Another consideration is that the giant mass of a industrial space colony would take thousands of times more energy to moove , than a compact lifesupportsystem for a hundred people , or a “tin can” as someboddy scornfully named it …

  • Warren April 19, 2012, 16:29

    @Ronald: “Late joiner in this thread on worldships, space colonies etc. versus planets….No, strongly disagree: as I have often argued on this website, planets are vastly cheaper per unit area per year than any space colony. “

    Yeah, I’m usually a late comer and the thread is dead (just as it’s getting interesting) so I rarely post comments. I do not recall your comments but would enjoy reading them. I have not done the arithmetic, but I have no idea where you get your cost estimates. Your comparison of sea platforms to land seems to ignore the cost of the starship development, the voyage, the likely cost of terraforming and the centuries of transit time.

    If we get serious about manufacturing our own land, it is easy to imagine automated facilities and robot systems to detect and deliver the needed raw materials. I would think that this process would begin early, in the asteroid belt, while the settlements are still dependant on the sun for energy. Why not talk about large pre-fab settlements eventually coming off of the assembly line often, like blowing bubbles? Geez, maybe, someday, we could each have our own 200km^2 bubble or build them to planet size if that is safer. Perhaps the factories could sometimes blow out copies of themselves. O’Neill thought a first generation settlement could have been constructed by the’90’s using the technology of the last century.

    Centuries before the founding of the first town on a planet thirty light years away, we could have a very large population of humans living in the Kuiper belt and probably well beyond. Sure, maybe comfortable settlements can and will be built on Mars and Ceres first, but if we master the art of making our own worlds, to our specs, there are no limits (unless ET objects).

    Our descendants might, for some reason, decide to “conquer” the galaxy, but those guys will not be human, any more than I am still a fish. I expect they’d be totally adapted to the interstellar environment with no need whatsoever for a habitable planet, habitable zone or an O’Neill habitat. They live in the space between the stars for free.

  • Warren April 19, 2012, 17:55

    @jkittle: “This actually may be part of the answer to the Fermi paradox.. but why aren’t our asteroids inhabited by alien colonies? Maybe we have a system with too few low mass objects mass to merit much attention?”

    Yes indeed. Right on to you. This does seem very much relevant to the Fermi paradox. I would think that hot spots in the Kuiper belt or Oort cloud would be of great interest. The asteroid belt, though, may be much too close to the sun.

    Yeah, we’re off topic here but I can’t resist. To beings adapted to interstellar space, our “habitable zone” and nearby may well be a very scary place, certainly not someplace where they would want to live or need to visit at all. If there were alien colonies in the asteroid belt, though, how would we know? There is no real reason to believe they would be making a lot of noise. There could be trillions living in nano-cities all over the solar system and we would not have a clue. We are not talking about hairless African primates adapted to the savannah but about beings who have been in control of their own evolution for tens of thousands to billions of years. It seems absurd to believe that we have any idea what to look for or any idea how they would behave.

  • Rob Henry April 19, 2012, 18:59

    Joy your eusocial crew is a strange and interesting one. My suspicion on the perfect type of crew is also that would be unnatural, but I lean towards an even mix of women and eunuchs. This would have advantages of being closer to our natural state and having been tried before with seeming success by some Eastern potentates.

    We might be familiar with the interactions of genetically identical siblings and their heightened cooperation vis a vis multizygotic ones, but we have no such data on ones of different ages. I am wondering if their elders become dangerously overprotective.

    I see your point of the usefulness of a single captain, but see no reason that she should be at the apex of any social hierarchy. I think that their should be a governing body – that might even constitute the entire remainder of the crew, that would rule supreme on all issues that were not mission critical.

  • Eniac April 19, 2012, 21:02

    On living in interstellar space: not likely. The Oort cloud maybe, if sufficient nuclear fuel can be found, but not empty space. There are no resources there, no energy. Nothing to sustain life. Life will have to be tied to stars, in one way or another. Interstellar space is for transit, only, with stored or transmitted energy and materials originating in star systems.

  • Daniel Alman April 19, 2012, 22:12

    Well i think some of the main limiting factors in building such a world ship are:
    1) Long term threats to the overall health of the ecology stored in the world ship. Such as cosmic rays and stuff like that. We wouldn’t the inhabitants to slowly go extinct out after years of continuous infertility caused by radiation damage.
    2) Technological progression on planet earth. The builders of the craft would be donating a LOT of money and resources to building such a craft that would not return and would take centuries or millennium to arrive. It could be possible that the descendants of the “volunteer” colonist could arrive to a planet colonized many years before due to advances in propulsive technology.
    3) Psychology of the inhabitants. The psychology of the inhabitants would be a major concern. Designers and planners would want to see paranoid nationalist isolationist movement erupt on one of these quadrillion dollar vessels. Such social and political activity could render the mission unsuccessful.

  • Ronald April 20, 2012, 4:21

    Warren: I did some back-of-the-envelope calculations of cost per unit area per unit time, some time ago (I forgot the post and searching within comments is not possible).

    Roughly:
    – A space colony: 1000 km2, 1000 year lifespan, 100 billion (10^11) US$ net present value (NPV), exclusing maintenance cost, are probably rather high. This works out as 100,000 US$ per km2 per year.

    – Terraformed terrestrial planet: 100 million km2 of inhabitable area, 100,000 years of stable lifespan (note: this is very short for any planet! It assumes a gradual reverting to unfavorable atmospheric conditions, which could most likely be easily prevented or mended), 1000 billion = 1 trillion = 10^12 US$ NPV. This works out as 0,10 US$ per km2 per year.

    Even if you modify these parameters somewhat (particularly the lifespan and cost of the planet), the outcome is always overwhelmingly in favor of the planet.

    And this still ignores three important facts in favor of a planet:

    – Planets are intrinsically/inherently long-term stable platforms, whereas any space colony (except maybe an adapted asteroid) is not. Put simply: a planet is naturally there and it does not fall apart, a space colony has to be manufactured and (intensively) maintained.

    – Planets are very large and therefore run very low risk of total extinction (i.e. there is nearly always refuge space from where to recolonize), whereas a space colony is a relatively small island which runs a much greater risk of total extinction, either by internal or external stochastic (random) forces. This is one of the fundamentals of island biogeography, the reason why island species are at much greater risk of extinction than continental species.

    – A great part, probably even the greatest part by far, of the ‘refurbishing’ of a potentially habitable terrestrial planet (in other words: terraforming) can and will be executed by the resilient self-replicating microbots that we know as microbes ;-). As Ole Burde also mentioned, this process can be much faster and cheaper (both because of the rapid and easy self-replication of microbes) than many realize.
    Once a potentially habitable terrestrial planet with a primordial atmosphere is found, adapted micro-organisms can multiply and convert it at exponential rates.
    I think that a future of interstellar colonization and terraforming largely hinges on biotechnology (in fact even the terraforming and colonization of Mars).
    The suitable planets (i.e. roughly right size and composition, right light and temperature conditions, water, primordial CO2/N2 atmosphere) are undoubtedly there. Of course we first have to get there.

  • Joy April 20, 2012, 6:14

    Hi Rob,

    Yes, I can see your idea also. The Chinese found the (much slandered) eunuchs to often be good administrators. They had enough drive to do their duties with diligence and vision, but being genetically incapable of forming a new dynasty, were not a threat to the status quo. You let ordinary reproductive humans loose in a sealed environment with a fixed population and the Darwinian genetic competition would go into overdrive.

    I can think of two types of worldships, one would be an automatic system with humans as a bipedal primate colony cargo, essentially fed and caged until arrival That could devolve to the law of the jungle and it wouldn’t matter as long as they didn’t go so crazy as to wipe themselves out.

    The other would be a properly crewed ship where the humans would have access to the controls for propulsion and life support. A truly crewed ship would definitely need a chief executive with ultimate authority, it just doesn’t work any other way. The captain need not be the smartest person, just someone willing to lead that the others are willing to follow. That’s how it works on nuclear subs.

  • Steve Bowers April 20, 2012, 8:38

    The most likely scenario would be
    1/ Send out a worldship that takes tens of thousands of years to arrive
    2/Develop faster ships in the home system
    3/Worldship arrives to find colony already well established in the destination system.
    That doesn’t mean to say that the worldship strategy is not worth doing; just be prepared to arrive as anachronistic late-comers when you get there.

  • ljk April 20, 2012, 9:28

    Rob Henry said on April 19, 2012 at 18:59:

    “Joy your eusocial crew is a strange and interesting one. My suspicion on the perfect type of crew is also that would be unnatural, but I lean towards an even mix of women and eunuchs. This would have advantages of being closer to our natural state and having been tried before with seeming success by some Eastern potentates.”

    Eunuchs? Are you saying that the Worldship women won’t have feelings and needs similar to men?

    The more baseline humans keep being shoehorned into the non-FTL interstellar journey plans, the less I am convinced they will be of benefit to exploring other star systems.

    As I said before, this does not mean that some future groups won’t try to fly off to Alpha Centauri in a hollowed-out planetoid or metal cylinder just the same, but to keep the status quo over many generations without draconian measures seems even more difficult than building an actual starship.

    Maybe they all need to be plugged into a virtual world ala The Matrix so that the crew do not know they are in a confined vessel quadrillions of miles from home and rescue. But when do you tell them the truth and how will they respond to that? Like I said, the human factor just becomes more complicated and less sanguine.

  • ljk April 20, 2012, 9:33

    Warren said on April 19, 2012 at 17:55:

    “If there were alien colonies in the asteroid belt, though, how would we know? There is no real reason to believe they would be making a lot of noise. There could be trillions living in nano-cities all over the solar system and we would not have a clue.”

    Do not say such things around here, Warren. You will be accused of believing in elves and trolls and angels. Even though ironically, future humans may be inhabiting the planetoid and comet belts themselves.

    [Whispers] But yes, flying under the current human radar should be a piece of cake for anyone who can actually make it to the Sol system. [End whispers]

  • ljk April 20, 2012, 11:36

    We have to start somewhere. Here is NASA’s new book on space psychology online in PDF format:

    http://history.nasa.gov/SP-4411.pdf

    The truth is that after 51 years of sending humans into space (primarily Earth orbit and in a few cases out to the Moon for a matter of days with Apollo), we still have much to learn and publicly discuss about humans living in isolated communities in deep space.

    We probably won’t start getting some really useful data in terms of psychology and social interactions until we start having non-professional astronauts and cosmonauts up there. Most government agency sponsored “star voyagers” are more than a little reluctant to admit to problems which could get them grounded to say nothing of public embarrassment.

    We also really need to get past the puritanical attitude towards reproduction and its surrounding behaviors that NASA has displayed since day one, otherwise those Worldship plans are really going to tank.

  • Ole Burde April 20, 2012, 17:59

    “It could be possible that the descendants of the “volunteer” colonist could arrive to a planet colonized many years before due to advances in propulsive technology.”
    It could also be possible that no starships would ever be build , because the planet ran out of critical rawmaterials , causing wars and ecnomic decline ,while everyboddy waited confidently for better propulsiontechnology.

  • Joy April 20, 2012, 18:36

    “Dragonfly: NASA and the Crisis Aboard Mir” is a great book by Brian Burroughs critical of NASA astronaut Linenger’s behaviour on board the Mir space station. NASA pulled strings to get a person who epically failed the Russian psych tests back on the flight roster. The Mir missions should have been a doodle, really no more challenging psychologically than men going to sea in sailboats. Yet things got so bad that Linenger was abandoned outside MIR alone after a difficult EVA. Linenger eventually found his own way back to the airlock before his air ran out, but at that point his shipmates couldn’t care less whether he made it back alive or not.

    We won’t even mention the strange case of NASA astronaut Lisa Nowak. The human challenges in building space colonies or worldships might be even greater than the engineering challenges.

  • tesh April 21, 2012, 5:31

    Looking at quite a few of the comments, is seems possible that we will never “solve” the problem of how stability of crew members will be reached. Each ship is likely to have a slightly different set of problems and circumstances particular to their journey. Thus, every ship will require a different set of rules, possibly a set that can only fully mature as the journey progresses.

  • Warren April 21, 2012, 13:24

    LJK:  OK, point taken.  Writing anything that is not to be taken literally is dangerous in any web discussion. And when any mention of the possibility of direct, real time, contact with ETI ruffles lots of feathers …….  What I  “believe” is “We don’t know”; hope that is clear from the context.  …also hope my would be accusers will at least hold off the attack until I post my first UFO story or find a new castle on Mars (CHUCKLE!!!).

    Ronald:  Thanks for repeating.  I found your discussion with the Greg Matloff interview last August. https://www.centauri-dreams.org/?p=19423.  You make a a good argument for settling nearby bodies, but the “we’ve got to get there” is the big one when we are talking about light years and centuries.

    An artificial world can be of any size, …Dyson sphere to a private little terraformed family comet.  Dozens to millions of tiny biospheres could be positioned very near to each other, in swarms. Small settlements need not be isolated at all.  

    I’d also point out that reaching the stars, eventually, with an expanding wave of conected O’Neill colonies, as discussed,  may go a long way toward solving the stability problem you bring up as well as as the social problems discussed at length here.

  • Eniac April 21, 2012, 18:32

    @Ronald:

    – Planets are intrinsically/inherently long-term stable platforms, whereas any space colony (except maybe an adapted asteroid) is not. Put simply: a planet is naturally there and it does not fall apart, a space colony has to be manufactured and (intensively) maintained.

    Unless you are thinking our colonists should revert to stone age status, living on a planet entails quite a lot of manufacturing and maintaining, also. Less than a space colony, for sure, but the gap will likely narrow in the future, and the cost decline.

    – Planets are very large and therefore run very low risk of total extinction (i.e. there is nearly always refuge space from where to recolonize), whereas a space colony is a relatively small island which runs a much greater risk of total extinction, either by internal or external stochastic (random) forces. This is one of the fundamentals of island biogeography, the reason why island species are at much greater risk of extinction than continental species.

    This is only a problem for species who are confined to one island. Twenty independent space colonies which can serve as each other’s refuge will be less likely to go extinct than a single planet, because they cannot all be hit by catastrophe at the same time.

    – A great part, probably even the greatest part by far, of the ‘refurbishing’ of a potentially habitable terrestrial planet (in other words: terraforming) can and will be executed by the resilient self-replicating microbots that we know as microbes ;-). As Ole Burde also mentioned, this process can be much faster and cheaper (both because of the rapid and easy self-replication of microbes) than many realize…

    Sure, it is easy to throw down some bugs and wait a couple of centuries, and voila, the planet is “terra”-formed. Or, maybe, “something”-formed, something not resembling the green hills of Earth at all. A brown cover of slime, perhaps. Very hard to predict, and not a lot of chance for perfecting the method by trial and error. And in the meantime, our colonists need to live in artificial habitats, anyway, to which they will have gotten quite accustomed after a few millenia of trying to terraform…

  • Eniac April 21, 2012, 22:03

    [Whispers] But yes, flying under the current human radar should be a piece of cake for anyone who can actually make it to the Sol system. [End whispers]

    You say we don’t know anything about them, and yet you are sure that they would want to hide from us. It is this presupposition of stealthiness that evokes the comparison with elves, rightfully so.

    A whole civilization of aliens, living their lives constantly and permanently obsessed with remaining invisible to us? Each and every one of them? You must be kidding. Get real.

  • Ole Burde April 22, 2012, 16:44

    “Sure, it is easy to throw down some bugs and wait a couple of centuries, and voila, the planet is “terra”-formed. Or, maybe, “something”-formed, something not resembling the green hills of Earth at all. A brown cover of slime, perhaps.”
    “Easy” ? If we ever get to seed other worlds with life it will be very , very difficult in all possible ways , and it will only happen after great advances are made in the almost nonexistent field of artificial ecosystems.
    Its never enough to have a “plan A” if you want to overcome areally hars problem , you need plan B and C as well .
    Plan A is to develop industrial spacehabitats , and eventually travel to anther star in such a habitat containing thousands of people , a habitat capable of surviving in another starsystem using only spacematerials ,such as asteroids and comets . No earthlike planets necesary.
    Plan B is the “Tin Can” where a hundred people and their decendants travels to another star in the cheapest possible way , capable only of surviving if they can land on an earthlike planet with an oxygen atmosphere ,and utilize its resources on a limited technological level . This ofcourse only becomes relevant in case Plan A ” doesnt work out” .
    Plan C is something even cheaper , in the short term . If no oxygen atmosphere is found , and no spacehabitats are build , the only way forward might be to seed a few planets with life , and wait for an oxygen atmosphere to become detectable . Such missions might be relatively cheap , because only a few kg of cargo is necesary , and because braking can be done at very high G , or perhabs be comletely eliminated .
    To detect ” Brown Slime” after a hundres years would be an incredible sucses , a good reason to break out your best champagne .

  • ljk April 22, 2012, 17:44

    Eniac said on April 21, 2012 at 22:03:

    From LJK – [Whispers] But yes, flying under the current human radar should be a piece of cake for anyone who can actually make it to the Sol system. [End whispers]

    “You say we don’t know anything about them, and yet you are sure that they would want to hide from us. It is this presupposition of stealthiness that evokes the comparison with elves, rightfully so.”

    I did not say ETI would want to hide from us. What I am saying is that if they wanted to for reasons such as studying us unobtrusively or simply not wanting to talk to us right now for whatever reason, it would be quite easy to do if they are in our Sol system. So the key words here are WANT TO if such being so desired, not that they are.

    “A whole civilization of aliens, living their lives constantly and permanently obsessed with remaining invisible to us? Each and every one of them? You must be kidding. Get real.”

    Again, read what I wrote above, and stop overhyping what I am saying to make my words look foolish.

    In my opinion, most ETI are nowhere near our Sol system and very likely have far bigger concerns than the juvenile actions and squabblings of a species that can barely keep its technological society together.