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On the Role of Humans in Starflight

What does it take to imagine a human future among the stars? Donald Goldsmith asks the question in a recent op-ed for Space.com called Does Humanity’s Destiny Lie in Interstellar Space Travel, playing off the tension between successful robotic exploration that has taken us beyond the heliosphere and the human impulse for personal experience of space. Along the way he looks at options for star travel both fast (wormholes) and slow (nuclear pulse, or Orion).

A fine science writer who worked with Neil deGrasse Tyson on Origins: Fourteen Billion Years of Cosmic Evolution, Goldsmith nails several key issues. The successes of robotic exploration are obvious, and we’re in the midst of several more energizing episodes — the arrival of Dawn at Ceres and the approach of New Horizons to Pluto/Charon, as well as the recent cometary exploits of Rosetta. We have much to look forward to and, as mentioned yesterday, new impetus has arisen for the Europa Clipper mission, which would constitute a fine tandem operation with the ESA’s Jupiter Icy Moons Explorer.

Freeman Dyson, in fact, thinks the success of robotics is so marked that the real work will necessarily be done by machines, with human travel in space in the category of entertainment rather than science. But Goldsmith finds this unsatisfying, and I think he speaks for quite a few people when he says a human presence on places like Mars speaks to our deepest impulses:

Just about everyone welcomes new information about the solar system, but what many really — really — want is for humanity to plant its boots on new soil, as Earth-bound explorers have done for many centuries. Lonely humans in space speak directly to our emotions, but pioneering spacecraft far less so. (Even an apparent exception, such as the hero of the movie “WALL-E,” connects with us through its seeming humanity, a fact that won’t surprise anyone who reflects for a moment on how storytelling works.)

Machines get more powerful at a mind-numbing pace, while the evolutionary changes that help us adapt to new environments move with far slower rhythms. Hybrids of human and machine may one day be feasible, or some kind of mind-uploading (a prospect I still think unworkable, as it tries to fit a consciousness that is the result of evolution in a physical body into an alien matrix). There is also the prospect of artificial intelligence achieving human-like capabilities, as witness the poetic, deeply introspective star-probe of Greg Bear’s novel Queen of Angels.

But for those who insist upon human bodies aboard a starship, these options aren’t enough, which leads us to the confrontation with the reality of distance, the nearest star, Proxima Centauri, being approximately 260,000 times the distance from the Earth to the Sun. Goldsmith takes a look at the Project Orion study in which Dyson played such a major role, envisioning a spacecraft that would be driven by a series of nuclear explosions behind the craft, their energies extracted by a pusher plate and a crew-saving system of enormous shock absorbers.


Image: An early conception of Orion as an interplanetary vehicle, one that would eventually be reworked into Freeman Dyson’s interstellar design. Credit: Adrian Mann.

Dyson’s 1968 paper on the ultimate Orion, a starship capable of reaching the nearest stars in 140 years, gave us what Goldsmith calls ‘the gold standard for visions of interstellar travel,’ in that Orion used technologies not impossibly far from what was currently available. But it’s telling that Dyson still sees the key requirement for interstellar flight as a society that can think in terms of centuries and work with long-term planning and execution of generational projects. Orion ran afoul of test ban treaties and the ever-controversial issue of radiation, but in any case it’s hard to see a culture with such short time-horizons as ours building such a vessel.

I’m glad to see Goldsmith referring to Steve Kilston’s ideas on slow expansion, which throws out the false dichotomy between fast results or none at all. Kilston’s idea is best described as a worldship, one we’ve looked at before in these pages. An astronomer and something of a philosopher, Kilston believes that within 500 years we will be able to build a vast structure capable of carrying a million people on a journey at a small fraction of the speed of light. It’s a generation ship, and one that banks on serious changes in the human outlook. Says Goldsmith:

Kilston’s “Plausible Path,” like any other low-velocity journey, requires that generations upon generations of spacefarers pass their entire lives short of their goal. Today, this plan would attract few volunteers. But if human society came to feel sure of its long-term viability, so that our time horizon stretched beyond the current limits of (at most) our grandchildren’s lifetimes, the situation would become quite different. Perhaps the wisest aspect of Kilston’s plan lies in its final pre-launch phase: a 100-year cruise through the solar system to demonstrate the full feasibility of the spacecraft and the willingness of its crew to pass their lives in space.

You can read more about Kilston’s ‘plausible path’ in The Ultimate Project, a presentation the scientist made at the Jet Propulsion Laboratory back in 2006. What he is arguing is that starflight will not become a reasonable expectation unless we reach a point where at least some people think that travel times of thousands of years are acceptable given the goal to be accomplished. Here I want to quote Kilston himself, from a comment he wrote on this site in 2013, responding to a suggestion that there may be reasons for interstellar flight that are irrational:

I’m not sure there is such a thing as an “irrational reason” — explanations and motivations certainly should pay attention to emotional factors. The pursuit of long-term goals and dreams is as vital for our mental and societal health as a concern and empathy for other humans is.

Children respond with wonder and enthusiasm when they hear about a grand project like interstellar travel. It can continue to magnificently inspire them long after we initiate it. As Pierre Teilhard de Chardin wrote, “The future belongs to those who give the next generation reason for hope.”

Goldsmith himself seems to be in this camp. And I think he’s practical enough to acknowledge that the outcome is very much up to us. There is no certainty that our species will ever attain interstellar flight, but if we are to make it happen, we’ll have to learn how to live off the Earth long-term. That would in my view involve ever increasing colonization within the Solar System to master the technologies needed for starflight and the human issues of survival in deep space.

At that point, I see no reason why space habitats on the scale of what Steve Kilston has long studied could not be built, either as explicit starships or as O’Neill-style colony worlds. Would generations accustomed to living in constructed habitats like these eventually decide to take one of their vessels all the way to another star? We have trouble imagining people who would be willing to live this way, but several centuries of technological development and experience in space could make the prospect far less onerous. I agree with Kilston that it’s a plausible path, and whether it happens or not, we still have rapidly advancing artificial intelligence to fall back on. In one form or another, I think human efforts will indeed result in interstellar journeys.


Comments on this entry are closed.

  • william February 5, 2015, 10:51

    In the movie ‘Interstellar’ I was especially impressed with the fact that the astronauts were placed in a sleep mode type of tank apparatus. It is said that space travel like warfare is long periods of boredom punctuated by intense adrenaline producing activities, I believe that to the very maximum. Especially long voyages to the outer planets of the solar system (unless there is some type of extraordinary propulsion system developed). This will be primarily a waiting game in which you are in some type of ballistic trajectory to your target.

    Thus humans can be in outer space with us humans can be in outer space, with the proviso that something be done to keep them either occupied or unconscious. In the event that you are going to deal with humans as being part of your cargo, then you are going to need people who are extraordinarily motivated to undertake this mission and all the associated risk and boredom with it, or you’re going to need people who can be rendered unconscious for long periods of time.

    In connection with all this I have often felt that the most promising type of suspended animation (although I hate the word suspended animation since this has the implication that people do not age, which is a far from proven fact) is the type of animation in which a person would be sustained by a some type of food product that would yield no sustainable solid waste, thus keeping the individual able to be non-wakened. If you have to perform solid elimination you will have problems with keeping the person a sleep. Whether or not such a feat can be performed due to special biochemical needs of the human body is an interesting question, at least to me.

  • william February 5, 2015, 11:23

    “Orion ran afoul of test ban treaties and the ever-controversial issue of radiation, but in any case it’s hard to see a culture with such short time-horizons as ours building such a vessel.”

    With regards to information regarding nuclear tests (for what it’s worth on the accuracy part). I submit the following:


    Supposedly, that this test showed the almost lack of radiation in a nuclear bomb. So take it for what it’s worth


    17:56.00.3 27 May 1956 (GMT)
    5:56.00.3 28 May 1956 (local)

    Bikini Atoll, Eninman (Tare) Island

    Test Height and Type:
    Surface burst, Height 9 Feet

    3.5 Mt

    The Bassoon device fired in Zuni was the first test ever of a three stage thermonuclear design. Surprisingly, this substantial innovation was also the first successful thermonuclear device design ever fired by Lawrence Livermore (then known as UCRL, now LLNL). The configuration fired in this test was a “clean” (low fallout) version that used a lead tamper around the thermonuclear third stage. Only 15% of the energy yield was from fission. A “dirty” version of this design, the Bassoon Prime device, was later fired in Redwing Tewa. The predicted yield for Zuni was 2-3 Mt.

    The Bassoon device was 39 inches in diameter, and 135.5 inches long. It weighed 12,158 lb. Crater dimensions were 2330 feet wide, 113 feet deep.

    This design was later developed into the Mk-41 bomb, the highest yield (25 Mt) weapon ever deployed by the U.S.

  • Erik Landahl February 5, 2015, 12:47

    Humanity’s survival beyond the 21st century depends on the creation of a frontier with the promise of a new beginning that allows hopes and dreams to be realized. In Earthbound society, one’s hopes and dreams must overcome the stifling, discouraging, nearly omnipotent power structure on Earth, ruled with an iron hand by the symbiotic co-regency of corporations and politicians.

    These two great rulers of Earth coerce the vast majority of humankind to value money and entertainment above all else. This society they created is destined to implode if it continues on this path. There is no sign yet that its rulers desire to change direction.

    Humans must be able to develop faith in the existence of a frontier where talent, determination and unshakable belief in one’s ability are the elements needed for hopes and dreams to come alive. The development of such a frontier would be a lifeboat for humanity. Space is the only place this frontier can be created. Robotic probes or artificial intelligence can’t create it. Only humans can.

  • ljk February 5, 2015, 14:01

    I wrote about The Ultimate Project here back in 2008, complete with an interview with Dr. Kilston:


    To be honest I was and am still skeptical about a constitution keeping a Worldship crew happy and in line, but perhaps if it took on religious meaning….

    Should we ever decide to send actual human beings to the stars, by the time it happens they will no doubt not be quite the same humans we are dealing with now. They may be modified in such a way that living for generations in deep space won’t be the hotbed of problems a baseline human crew would likely encounter.

  • Ron S February 5, 2015, 14:22

    This problem of short-term-ness brings to mind a time in university when (for no good reason) I studied number theory. We came to work on several classes of problems with no analytical solutions but that could be solved numerically. That is, by computer. These could take a long time, even an indeterminately long time.

    A professor of mine discussed this point. He defined infinite solution time to be any solution which takes longer than our attention span. More such problems are solvable today, since computers are much faster, yet our attention spans are much the same.

    The same is true of interstellar travel. Go faster or find ways to hold society’s attention for longer. As stated in the article the idea of interim, incremental objectives with concrete value could do it. There is still no guarantee that a future generation’s attention won’t wander, but that’s for them to decide.

  • Alex Tolley February 5, 2015, 17:05

    If we just want to get reports of what is out there, machines are sufficient. They are the proxy for explorers of old returning from their explorations of distant lands.
    If we need to see things in real time, we need instantaneous communication ( new physics).
    If we need to be there, my best guess is to send fertilized eggs, or a means to construct them, and create humans “at the target”.
    If we can upload minds and embody them in androids, this would be the best way to directly experience the stars.

    Looking at Kilston’s presentation, it looks hopelessly expensive compared to the above alternatives. In addition, the target worlds are so limited in suitability, that machines are going to be much more suitable if planetary colonization is desired.

    For O’Neill’s, cycling within the solar system makes a lot more sense than striking out to the stars. There is energy and resources, recycling will be less stringent. There will be both information and physical access to solar system civilization. Humans living in such worldlets may not see any advantage in star traveling except to find new energy and resources around another star. But the problem may be that robot AIs will long since have laid claim to those stars and resources. They will be the “spacers” of Asimov’s robot stories, constraining Earth humans to Earth.

    Humans will expand into the solar system, with O’Neill’s as the preferred habitat for most of solar system humanity. Robots in contrast will colonize the physical bodies as well as free space. More importantly, robots will do this well in advance of humanity, and also populate the stars simply because they can do this much more easily and cheaply than humans. If robotic AI ultimately exceeds human intelligence, then I see little reason to doubt that robots will be the inheritors of the stars. Humans in meat form are not adapted to conditions off Earth. If we are to go to the stars, I think that we will have to be in a different form to achieve this, even if new physics overcomes the main barriers to star flight.

  • rms February 5, 2015, 17:13

    “Freeman Dyson:…real work will necessarily be done by machines, with human travel in space in the category of entertainment…”

    To be fair, ‘entertainment’ cheapens that quality of human desire somewhat, though I think he’s correct in saying machines will do the work. It will be human consciousness, it’s desire to know/explore/experience, that will make the endeavor meaningful.

    Another of Dyson’s quotes from the reference article says:
    “If you want to have a program for moving out into the universe, you have to think in centuries, not in decades.”

    This long-term thinking is the core of the question. I’ll offer that it comes hand-in-hand with moving out into the universe, with the proviso that it will take generations to develop…if–and this is a big if–each successive generation accepts the concept and passes it to the next.

    All the baby steps and backslides by space-faring nations, continuing apace into any foreseeable future, contribute to both moving out into the universe and strengthening a culturally intrinsic long-term sensibility. Too bad, this alone is not enough. A mature long-term perspective would do wonders for all aspects of humanity, and Earth in general.

  • Harold Daughety February 5, 2015, 17:19

    Space travel may save the species but cannot solve overpopulation on earth. If near earth space colonies are meant to absorb population growth they will fail: there is an old textbook example that if a particular country sent its people four abreast in a fast walk into oblivion the remaining population would continue to grow. There is no way that space habitats could be built fast enough: population limitation is a necessity for human life on earth is to continue. There is no reason to believe that will happen.

    If people can live in space habitats and not die of boredom, then they can live in multigenerational starships. Other than power sources, they seem to be essentially identical. Planetary colonies then have no purpose.

    In a short story I wrote in a writing class (never submitted for publication) a con artist escaped arrest by stealing a prototype stasis chamber. He arrived 300 years in the future to a world that, other than himself, was populated by women, a communal agrarian society of mid 19th century technology except with wind generated electric power. New births were created by fertilizing an egg cell with a bare nucleus of the other parent. As it was explained, every child was planned, every child was wanted, loved and valued. The population was 10 percent of the old earth and dropping. He was warned that he had no humyn rights and would be terminated for any violation of rules. He was giving the job of shoveling out the stables for he had already demonstrated a facility in throwing manure around.

    Such a static society with self- limiting births can survive indefinitely. I simply ask the question, but why? The last scene of On The Beach (1959 movie, directed by Stanley Kramer) was for me, is some odd way, comforting.

  • Black Sci-Fi February 5, 2015, 18:11

    Our species needs cooperation from our entire planet to undertake such an elaborate venture. We can’t even cooperate as well as bacteria or virus. The term ” space nations” is used in most sci-Fi novels where old world colonialism is celebrated to segregate us one fom another. The irony is that world destroying events caused by industrial pollution should be the target of all of this investment in technology. Are we really so shortsighted to have dreams based on running away from our planet, with no real alternative planet known..?? What type of pollution will atomic rockets leave in NEO..??
    The advance of humans into deep space will parallel our advance toward being a species that regards all human life is precious and needed to increase the odds of quantum leaps in technology.

  • william February 5, 2015, 19:02

    In the third entry in this comment section, the person stated that those who go to the stars will have to be almost a divine type of being pure in thought and word and deed, and able to grapple with all types of morality questions.

    Since I have often been times told that I can be perhaps blunter than may be best advisable, I’ll be the one to bite the bullet and ask the hard and dirty question(s) that possibly needs to be asked here and now.

    And that is simply the question of humanity; why does everyone believe that people who will make these journeys, whether within our solar system or to the furthest stellar system imaginable will be any less greedy, jealous, hateful, etc. etc. then, is shown on a day-to-day basis every day in the most despairing news events that we see every day ? These are just people who will be making the journey to expect them to be anything less than humans be lies the idea that people are just people no matter what the situation are the time in which something is transpiring. Any thoughts and comments on this observation ?

  • Astronist February 5, 2015, 19:19

    Why does Goldsmith call Orion ‘the gold standard for visions of interstellar travel’ when it was developed into the far more sophisticated Daedalus design over 30 years ago, and is continuing development now under the Icarus banner?

    Stephen A.

  • ProjectStudio February 5, 2015, 19:20

    I remember the 70’s sci-fi film Silent and the wonderful filming of the interior of its beautiful domed greenhouses resplendent with life. Life is its own purpose. Whether that continues on extra-solar worlds, in O’Neil colonies, or hybridised space trees floating through the Oort cloud, it is the continuation of that spark. On the Beach was a wonderful film too, with splendid character acting (Gregory Peck, Ava Gardner, Fred Astaire, Tony Perkins) that only underscores the charming warmth and worth of life if the face of the cold war’s maddening death wish.

  • Joy February 5, 2015, 19:27

    @Erik Landahl
    + 10^100!

    Our current oligarch owners would be happy with a 90% die off and return to the dark ages as long as they get to stay on top of the ruins. Nothing else matters to these people.

    Greece>Ukraine>Somalia is the progression of decay. The US, the EU, and Japan are at the pre-Greece stage but all will enjoy Greek conditions before the end of the decade. A frontier is necessary, but there is no hope of even building a small L5 colony without first debt repudiation and the establishment of an honest monetary system to replace private central banking.

  • Joy February 5, 2015, 19:51

    Re: Kilston’s ‘plausible path’

    Ok, with a modification to semi-plausible, I would agree. Slow voyages are exponentially more energy efficient than fast trips, so are preferred unless some magic energy source is discovered.

    Earth herself demonstrates that a almost closed system can maintain life for gigayears if powered by an external fusion power source. Exactly how big a sealed space habitat would have to be to support a biosphere + humans indefinitely is unknown. But, I agree with Gerard O’Neill that colonies on his scale (32 km long) at 1 AU from Sol would likely by sustainable as closed systems for at least thousands of years once built.

    My qualification relates to the problem of onboard power for the colony in interstellar cruise phase. This is actually a bigger problem than using external nuclear explosions to get the colony moving. Keeping nuclear reactors (fission or fusion) going for thousands of years in a closed system is nontrivial to say the least. The only viable system I can think of is to launch the colony with a large inventory of reactor cores and eject them into space when they reach the end of their service life.

  • tchernik February 5, 2015, 20:12

    First, I am a Singularity-skeptic. Not in the sense of rejecting the notion of accelerated, possibly exponential development for some areas for a while, but about the notion of “computing power presumably equal to human brain = artificial consciousness becomes fact”.

    I don’t believe we will crack consciousness as easily and as soon as Kurzweil et al believe. So in my view, we won’t have to deal with the problem of super-intelligent AIs exterminating us or taking the universe from us. They will most likely be there, they will even be super-human for many things… and they most assuredly still won’t be human-like, being mostly our super-talented servants for possibly a long while.

    Nevertheless, I also think scientists, artificial intelligence and robotics will be doing a lot of incredible things in the not so far term future. Including fully formalizing, simplifying and performing all the steps for industrial kickstart and self-replication in space. We will start with valuable resource gathering by drones for delivery to Earth, and move into resource processing for using them on space (e.g. transforming water ice into fuel, and then some asteroid ores into metals), then producing some derived goods, and finally into making complex assembled goods.

    And that’s when the fun starts. As such capabilities grow and become self replicating, they will eventually take us into building arbitrarily large amounts of space infrastructure in situ, with minimal or no human intervention.

    This process, once started, becomes practically unlimited. We eventually could build cities and manned bases in space, possibly without ever leaving Earth at all. Of course we will go up there, because we are human beings and we want to see and participate, but the real workers will be AIs and robots.

    Even without breakthroughs in physics (which is a naive expectation, even assuming only the now “standard” fields of physics & technology are and remain there), we could end up filling the Solar System with robotic infrastructure and human habitats in a relatively short time frame, on historical terms.

    Habitats and infrastructure that will be built with space resources (mostly asteroids), fed by the Sun and/or advanced energy sources (e.g. fusion) and built+maintained by robots.

    Of course, the volume of interest for humans will still be Earth and its immediate entourage. Just by virtue of such volume having the biggest number of humans living there. But as some people start moving into the opened frontier, that sphere of human interest will grow, until covering the Solar System.

    What then? isn’t the Solar System enough for having a good enough civilization? Well, most likely yes, and I think it probably will be so for a long while. Civilization can eventually reach a point of stability between human desires and capabilities that we don’t yet know.

    Because if we really think about it, in such a Solar System civilization we could grow our numbers, happily exist for millenia upon millenia, have plentiful resources, opportunities and peaceful living in space without ever leaving the neighborhood of the Sun.

    This civilization could even sate its curiosity about other stars and worlds, by pursuing the development of ultra advanced telescopes, very possibly taking them into the Solar gravity lens, peering and maybe mapping distant worlds with them. Enough knowledge and wonders to keep future astronomers and the public busy with news practically forever.

    But, if we remain human and don’t fundamentally change ourselves into other kinds of beings, I think we will retain that longing, that desire for seeing and knowing more, for being out there, at the ever expanding frontiers.

    Because at that point of civilization’s development, it would be more a matter of wanting it and following that desire than of practical possibility. Even if it takes generations of automated+human expansion into farther and farther worlds and worldlets, hopping from to the next deep into the void, humanity still can reach the Stars. Human life and history is more than the life of any individual or set of individuals, it’s a long and multitudinous flow of events.

    If any mixture of human longings, historical trends and technical capabilities allow it and start taking us there, we can be certain that one day, someone (or a lot of people at once) will reach the distant shores on other stars.

  • Andrew Palfreyman February 5, 2015, 21:15

    If we find a way to maintain roughly 1 gee all the way (using it for braking too) then 4.2 LY takes only about 3.5 years ship time. This is theoretically possible using staged micro black holes, but we shall have to wait some centuries for the tech to catch up with the physics.

  • Malcolm Davis February 5, 2015, 21:37

    The author suggests a 500 year time-frame to build a world-ship and travel times in thousands of years. I’ve posted on this group before the reasons I don’t think that this will work. By all means, we should be thinking about space habitats, O’Neill worldlets, converting asteroids to space colonies, and even terraforming as options. People can come and go from such colonies and return to Earth – its not a closed system and it works for this reason. But I do not support the idea of a group of humans, generation after generation, somehow living for thousands of years in one ship that is slowly crossing the gulf between stars at velocities little better than Voyager. Socially I think its going to be a disaster. Nor can such a solution be artificially managed through political imposition of some form of authoritarianism. Without exception (so far) every type of authoritarian system has failed.

    Uploading, and evolving humans into post-humans – I’m dubious about because we don’t know what a conciousness is, and if we don’t know that, we can’t transfer it to another structure, be it a super computer or a robot. And there are all sorts of ethical and moral dilemmas that the post-humanists refuse to confront. They are too entranced by the prospect of living forever almost as if Gods.

    So, finally, we come to putting ‘humans 1.0’ on ships and sending them to the stars. That’s challenging too because we don’t know how to accelerate a ship up to a reasonable fraction of the speed of light to make the journey to nearby star systems of acceptable duration (thirty to forty years). But I think that we should be trying to find a way. This is where much of the debate over interstellar travel loses meaning and gets sidetracked – people talk in ridiculously long time-frames and make an assumption that no progress or advances in propulsion, materials, energy physics or other areas will happen within centuries, so space arks are the only solution. I don’t think that will be the case.

    We are discovering more and more exoplanets and there is an increasing likelihood we’ll discover habitable exoworlds soon, potentially relatively nearby. At the same time, there are greater risks to long-term human survival on Earth from a variety of factors – climate change, the risk of nuclear war, potentially-hazardous near-Earth Asteroids, pandemics – take your pick. If humanity wants to survive for aeons, it must go to the stars, or to quote from Interstellar ‘Humans evolved on Earth but they were never meant to go extinct on Earth.’ But the survival of humanity will mean developing a means so that hundredsof thousands if not millions of humans 1.0 can go, and do it in a reasonable time-frame on many ships, not some unlucky few on some generation ship that becomes increasingly socially fragmented and fragile as the years progress. They tear each other apart before the ship even gets near another solar system.

    The future demands fast starships. That is what we should be developing. Interstellar travel for everyone. That’s the solution – my view.

  • Craig Watkins February 6, 2015, 1:05

    We’ve seen the steady extension of human life expectancy and I think soon we will soon see the growth in maximum life span. To me, it is much more feasible to project than FTL travel, suspended animation, massive worldships, or human level AI. What medicine and lifestyle can’t do, I think genetics can unlock. Genetically engineering children to live longer healthier lives seems like a much easier choice than choosing to bear children that live and die on a spaceship isolated in the depths of interstellar space.

  • stargazer787 February 6, 2015, 3:53

    With all respect to Professor Dyson, unless or until humans are replaced as the dominant intelligent species on Earth we, or our forebears, will have the lead role in interplanetary and eventually interstellar exploration and colonization – and not just as tourists. I regard the current preponderance of interplanetary exploration by unmanned probes as a transitory phase during which human deep space travel technology is being perfected. Once that is accomplished, humans will never settle for second place in the exploration and expansion into interstellar space. As our species advances the probability of hybrid humans combining the best features of biological and other advanced technologies seems likely to emerge as the human path forward and cement our role as the dominant species for the foreseeable future. These will be more advanced humans – but they will not be perfect or god-like humans and they will contain many of our imperfections.
    Regarding short and medium term prospects for human interstellar travel, barring any extraordinary breakthroughs in propulsion, massive starships multi-generation or world ships are inefficient, ineffective, and comparatively slow. More importantly, they pose the very real risk of loss of identity from with the mainstream human culture from which they were sent. This could easily result in a completely unpredictable result when the ship arrives at its destination – that is if the human passengers & crew don’t change their mind entirely and go off on a mission of its own purpose and design. The only serious justification I see for using one or more of these world ships is if the human race is facing immediate extermination and we have no alternative but to ship out every living being we can before Earth/Sol is destroyed.
    Under less catastrophic circumstances, to speed up the process of expansion of the human race and produce far better results, our best course of action would be to use smaller , higher speed probes with a cargo of adult humans in hibernation and a stock of frozen human/hybrid embryos. These vessels should be able to reach their target star systems in a matter of a few decades. As the vessel travels, it would be continually updated on technology, science and other developments thus reducing the risk of technological and social divergence from mainstream human civilization. This vessel would contain technology making it capable of replicating equipment needed to build O’Neill space habitats for human habitation and any other devices needed to create and maintain a fully functional long-term human colony in that solar system. After accomplishing an initial survey of their target solar system, the probe would seek out one or more mineral rich asteroids to be the source of necessary minerals to build essential ships and equipment and ice for water. These would all be one-way missions originating from Earth or other colonies. Theory to the contrary, it may still be possible to use quantum entanglement as a means of faster than light communication between human colonies and Earth and manned spacecraft coming from Earth or another home base. This would enable a “real-time” human civilization to exist on all colonized worlds and manned probes. Interestingly, this may also be the explanation for the lack of radio signals detected by SETI searchers.
    Unless or until we develop radically improved propulsion systems enabling us to travel close to or faster than light or an end-around allowing us to use worm-holes or warp space, this seems like the best way to expand the human race out to star systems up to say 20 to 30 light years from the Sol system. This should keep us busy for the next 500 to 1000 years by which time we should have resolved issues of the light barrier and faster ways to get between point A and point B.

  • Michael February 6, 2015, 4:18

    On such a long journey the spacecraft would most likely be over taken by faster crafts later on, so if the slow moving ship will be overtaken by the faster ones we could configure the slower ship with a faster ‘lifeboat’ on-board that speeds up to the faster ship which has the new tech and room for the crew leaving the slow ship behind. In effect we could have a stream of colonists moving to the stars at various speeds.

  • DCM February 6, 2015, 5:34

    “Harold Daughety February 5, 2015 at 17:19

    Space travel may save the species but cannot solve overpopulation on earth. ………”

    Overpopulation is an illusion, at best a temporary situation as long as people realize that crushing people into poverty and treating them as cattle solves nothing.
    The wealthier a social group the fewer children they have and the longer they live. Thus capitalism is the long term solution to “overpopulation” if we are to avoid a crash.
    Rigid control of people, the favored solution to anything of rulers, perpetuates disaster. It would prevent the long range development of space habitats and human survival.
    Don’t get caught up in that nonsense.

  • Michael Spencer February 6, 2015, 8:17

    Kim Stanley Robinson’s latest books imagine a near-term future where the solar system is populated over the course of the next few hundred years. During that time, humans become accustomed to an entirely different sort of life with the ability to move about the system; in the end, without spoiling these recent books, a logical progression of tech and lifestyle-comfort leads a group to make an outward trip.

    This makes sense. Extrapolating existing tech into an interstellar future, at least for me, sometimes borders on silliness: exploding atomic bombs to propel a spaceship? Really? Our interstellar future depends on tech not even imagined.

  • Wojciech J February 6, 2015, 12:27

    “Kilston’s “Plausible Path,” like any other low-velocity journey, requires that generations upon generations of spacefarers pass their entire lives short of their goal.”
    If we find suitable exoplanets nearby we can send ships where the first generation will still be alive upon arrival.This kind of diminishes the “generations of generations” effect.But personally I believe any good Oort-cloud alike system will do as will cometary discs and asteroids. These places are even better for space colonization than habitable planets(gravity well, potential alien life that has more value when not tempered with).

  • Daniel Suggs February 6, 2015, 15:10

    @Michael Spencer Which Kim Stanley Robinson titles are you talking about? I am about half way through ‘Red Mars’ and looking forward to the rest of the trilogy. Are they the books you mentioned?

  • Alex Tolley February 6, 2015, 20:16

    KSR. – 2312: A Novel

  • DCM February 6, 2015, 20:21

    “Wojciech J February 6, 2015 at 12:27

    …..potential alien life….”

    Exactly why I favor building ever more complex habitat ships that will eventually reach world proportions.
    Of course if we find potentially useable but uninhabited worlds we can terraform them. IF.

  • Jim Early February 7, 2015, 10:23

    The fundamental limitation of non-intelligent robotic exploration is that the invention, construction and launch of the probe must all occur on the Earth. The probe can have its programming updated, but that activity still requires active communication with Earth. Only humans (or intelligent robots) can ask new questions, find new goals, construct new machines, and launch new probes from remote locations on other planets or star systems. Only by going into space ourselves will we truly explore our universe.

  • Enzo February 7, 2015, 15:55

    “The wealthier a social group the fewer children they have and the longer they live.”

    Maybe. And what happens when the population grows faster than the wealth that is supposed to stop it ? Like Africa now :

    Some “illusion”

  • Ole Burde February 7, 2015, 16:05

    The bad news is , that the main bottleneck for achieving ”humans in starflight” wil not be technology . Just like today , the main thing holding us back is the cultural-political nature of the human being , or in short our selves . No major powers are going to give up on their gigantic investments in military systems , investments which are atleast a hundred times bigger than space budgets .
    Add to this an ever present resentment against the tiny spacebudgets from various ideological groups , which could anytime mutate or recombine into real destructive capabilities .
    There are no known reason to believe any of this is going to change .
    The good news is , that the very same human nature is capable of sucseeding against incredible odds . If the polynesians were capable of crossing the pacific ocean in canoes , and actually reaching almost any island worth living on , then surely we should be capable of living in a tin can for a few hundred years in order to reach another star . Many island populations were established in the pacific by less than thirty people ….. in short the understanding and incorporation of human nature will be the key to manned spaceflight

  • Wojciech J February 7, 2015, 16:08

    Regarding Robinson, he is now working on novel about generation ship and colonization of other star system. The title is “Aurora” and should be available in July this year


  • Lionel Ward February 7, 2015, 18:21

    Methinks that if we will be building human crewed interstellar vessels then they will be constructed from asteroid-mined metal, propelled by asteroid-extracted fuel, and launched from deep space cos its a whole lot better not to be needing to escape from a planet’s gravity-well before even getting started. Let us get along with the business of mining asteroids then, and building asteroid mining robots!

  • Moran February 7, 2015, 23:20

    A point often overlooked in amy discussions of interstellar flight is this – by the time we have the technology(large amounts of space-based mining, transport, and production facilities) to build a starship, and the societal will, space habitats are likely to exist. These habitats will have different social organisation than communities on Earth, as anyone who has read Heinlein’s The Moon is a Harsh Mistress will understand; in a place where even air is not free, and negligence can mean everyones death, things must perforce be different. The point is, that these societies, used to living in a ‘world’ that needs maintenance, are more likely to have the views and attitudes that would enable a slow-boat starship. Thus we should direct efforts toward colonisation of the Solar system, with interstellar travel as a logical follow on, rather than the prime goal.

  • Brett Bellmore February 8, 2015, 11:05

    Why is Orion, and not Daedalus, the gold standard?

    Essentially, because we know how to build Orion. Could start building it tomorrow. Daedalus is an interesting design, but the technology is purely speculative.

  • Antonio February 8, 2015, 14:06

    I think Dyson is totally wrong when he says that the exploration will be unmanned because robots are better than humans at the job. All exploration missions are unmanned today, yes, but that is only by political reasons, not efficiency reasons. Just compare the amount and diversity of lunar rocks bring back to Earth by astronauts (around 300 kg) and by robots (around 2-3 kg). Or compare Curiosity with a profesional geologist. An entire hour to run 30 meters? C’mon… And the human is many orders of magnitude more versatile, independent and capable (Curiosity can’t search for fossils, for example).

  • william February 8, 2015, 15:50

    Super great points on everything stated, and also too very thoughtful analysis. As an engineer, when I see problems I always go by the old tried-and-true rule (my own personal rule by the way that I made up) when you have two extreme positions, go for the middle!

    Societal stability in a closed ecological system. Fast is better than slow and 10 to 15% the speed of light is better than lightspeed (which is unattainable). Need people who can be dedicated to the mission, even without earth in dire straits to drive the project. Perhaps the Orion line type of system (microexplosions don’t exist, but clean thermonuclear bombs do-see my first comment) so a feasible means of propulsion DOES EXIST and we don’t have to wait for some kind of breakthrough that may be 1000 years in the making.

    “Theory to the contrary, it may still be possible to use quantum entanglement as a means of faster than light communication between human colonies and Earth and manned spacecraft coming from Earth or another home base. This would enable a “real-time” human civilization to exist on all colonized worlds and manned probes.” This quote from a individual above and does seem to have some merit as experiments are being currently conducted to check the reality of it. Keeps the travelers in the mix with what is going on back home allows them to keep their sanity.

    The only stopgaps appeared to be questions concerning radiation, closed ecosystems, dedication to what scientific resources must be employed and experiments that will need to be devised, psychological and social logical investigations will need to be ongoing, and finally the big bugaboo that is always in the mix: MONEY ! Unlike the Daedalus project, which would require special fuels, which you would be in a a huge drain in money and time to accomplish the clean fusion bomb(s) actually exist, and could serve as propulsion.

    Finally, targets: I would advocate that close by stellar systems (Max distance of permitted be 11 light-years; the epsilon system) as stopping points. Why? Simply because when you arrive, you are engaging the crew in something productive, which is not occupying them in what will hopefully be scientific pursuits. Obviously, you would choose a star system that would have marginally if not better planetary candidates where they might be able to spend some time and perhaps do some colonization. Brief and dirty tutorial, but one that has the elements of do ability, speed, reason, and doesn’t require that you go extremely slow, are extremely fast to reach a potentially useful target in a reasonable time frame (Decades?). There, I’ve given you my two cents worth.

  • william February 8, 2015, 18:58

    Secret stash of Moon artifacts found hidden in Neil Armstrong’s closet


  • DCM February 8, 2015, 19:56

    ” @DCM:
    “The wealthier a social group the fewer children they have and the longer they live.”

    Maybe. And what happens when the population grows faster than the wealth that is supposed to stop it ? Like Africa now :

    Some “illusion” ”

    Leftist dictators take over, keep most wealth, and let millions die from starvation and disease unless the people are able to slaughter the rulers and stabilize things.
    Scientific American, incidentally, is a leftist propaganda sheet that puts a negative twist on everything.
    Self-hatred is not objectivity.

  • ljk February 9, 2015, 11:45

    Limits to Growth was right. New research shows we’re nearing collapse

    Four decades after the book was published, Limit to Growth’s forecasts have been vindicated by new Australian research. Expect the early stages of global collapse to start appearing soon.

    Graham Turner and Cathy Alexander

    Monday 1 September 2014 21.15 EDT

    The 1972 book Limits to Growth, which predicted our civilisation would probably collapse some time this century, has been criticised as doomsday fantasy since it was published. Back in 2002, self-styled environmental expert Bjorn Lomborg consigned it to the “dustbin of history”.

    It doesn’t belong there. Research from the University of Melbourne has found the book’s forecasts are accurate, 40 years on. If we continue to track in line with the book’s scenario, expect the early stages of global collapse to start appearing soon.

    Limits to Growth was commissioned by a think tank called the Club of Rome. Researchers working out of the Massachusetts Institute of Technology, including husband-and-wife team Donella and Dennis Meadows, built a computer model to track the world’s economy and environment. Called World3, this computer model was cutting edge.

    The task was very ambitious. The team tracked industrialisation, population, food, use of resources, and pollution. They modelled data up to 1970, then developed a range of scenarios out to 2100, depending on whether humanity took serious action on environmental and resource issues. If that didn’t happen, the model predicted “overshoot and collapse” – in the economy, environment and population – before 2070. This was called the “business-as-usual” scenario.

    The book’s central point, much criticised since, is that “the earth is finite” and the quest for unlimited growth in population, material goods etc would eventually lead to a crash.

    Full article here:


    Slice it any way you like, the point is that Earth *is* finite and will not support our growing technological civilization indefinitely. Will humanity smarten up in time and do the right thing? Or will we wait until things get drastic and by then it will be too late, especially to do anything so ambitious as launch a Worldship to save at least some of our species and our culture.

    Will humanity learn from its past? We shall see.

  • david lewis February 9, 2015, 18:31

    “A million people at a small fraction of the speed of light”

    Pretty impressive. Wonder what sort of society they would have though? Certainly capitalism is out, other than maybe a system parallel to the one that would be needed to keep the ship running. I could see people writing games/books and creating other things for trade, but when it comes to the nuclear reactors the vessel would require, or the farms, or the systems that would keep the air breathable…. Doubt it. Certainly one would hope it’s at least somewhat democratic though.

  • david lewis February 9, 2015, 18:46

    Just to add … how to fund such an expansion into space.

    1. Rob the military of their funding for just “1” year, which globally might be as much as 2 trillion dollars.

    2. Build nuclear reactors, maybe 200 to 400 of them.

    3. Profits are used to fund the next generation of reactors, with any excess put into space research and infrastructure.

    We eliminate a major source of pollution, improving people’s health, and get permanent funding for moving towards a space-based infrastructure that isn’t dependent upon the whims the current administration of a certain country, or government.

  • Brett Bellmore February 10, 2015, 7:44

    “Limits to Growth was right. New research shows we’re nearing collapse”

    Thanks, I appreciate starting the day with a horse laugh.

  • Wojciech J February 10, 2015, 11:53

    “Wonder what sort of society they would have though? ”
    It would require centuries upon centuries of planning and control. I believe religious groups would be the right kind of societies to preserve the society and the mission.
    Of course that might not be the ideal society envisioned by these who envision such interstellar star vessels.
    Personally I believe a faster ship, with limited crew or no biological crew at all is more likely.
    However when it comes to colonizing space religious groups are quite interesting and provide good source of potential organized societies that would be interested to invest long term planning and resources into such projects:


    Hutterites are interesting because they have a concept of medium rural colony that starts another colony after it reaches certain size. They could be a good role model for small O’Neill type or asteroid colonies.

    Quiverfull see no limit to population growth and rising childbirths as a blessing.
    If it ever becomes restricted by world culture, and space colonization is viable, they might be tempted by potential unlimited space to grow even on certain limited areas like Bishop Ring.

    Of course that is just a nice SF speculation, but interesting nevertheless to demonstrate my line of thought.

  • DCM February 10, 2015, 19:54

    Religious type societies can be designed for such purposes.

    I have in mind constructing increasingly large, increasingly complex biosphere worlds that can after some centuries of functioning near home set out in groups of several with different social or biological environments.
    Much life can be included simply as DNA and life forms can be designed for various colony worlds or worlds that can be terraformed. Don’t have to keep earth creatures as such, though it’s also a good idea in some worlds.

  • Alex Tolley February 11, 2015, 16:22

    @DCM Don’t have to keep earth creatures as such, though it’s also a good idea in some worlds.

    That strikes me as a hubristic comment given the billions of years of co-evolved organisms creating ecosystems. Engineering new organisms to work similarly is a non-trivial task to put it mildly.

  • Larry Kennedy February 13, 2015, 14:38

    I love this discussion. I do have a problem with one assumption that is very common. It seems to be assumed that almost miraculous outcomes from “AIs” require a rise of consciousness. I disagree. I would say that fruit flies live in a much more computationally complex environment than interstellar probes, yet they do quite well without human style consciousness. After watching computation advance for a half century I have little doubt that it will evolve capabilities that we can barely imagine.

  • Eniac February 14, 2015, 0:52

    Larry Kennedy is right. Even the dumbest of living beings, bacteria, can grow successfully in environments more complex than interstellar space. Neither human control nor AI are required to fill the galaxy with machines.

    Nevertheless, it is quite plausible that our descendents in just a few hundred years will all be AI. It does not matter whether we manage to “upload” our own minds. We have never uploaded our minds to our biological descendants, so there is no need to do so for our prospective artificial offspring.

    Although, of course, from a selfish point of view it would be nice.