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Interstellar Missions from the Living Room

Seth Shostak and I independently hit upon the same topic yesterday, Seth in his regular venue on Space.com and I with a Centauri Dreams post that asked how advances in observational technology might replace actual interstellar travel. Seth’s take is somewhat different from mine, arguing as he does that while we’ll spread through the Solar System, we’ll likely explore the galaxy from home. I, on the other hand, argue that at least a small number of humans will find the means to make the long journey, but perhaps not in ways we often imagine.

Changing How We See Things

I return to the topic to get some of Seth’s observations into play here. For the point of both articles was that we’re making remarkable advances in how we see things, advances that are far more striking than what we’ve managed in propulsion. Thus it took seven decades to go from the V-1 moving at one mile per second to New Horizons, which moves toward Pluto/Charon at ten miles per second. A factor of ten increase in speed in seven decades, this occurred in a time when, as Shostak notes, our camera technology improved by a factor of ten thousand. Then this:

Now you might argue that human exploration is qualitatively different than sending mechanical proxies. We humans want to experience the frontier, not just watch it come up on our computer screen. We want to smell it, feel it, and look around.

OK, but what if we could send back all those sensations with a fidelity as good as being there? That’s becoming more and more practical. The bandwidth of a single human eye, recently measured at the University of Pennsylvania medical school, is roughly 2 megabytes per second. The bandwidth of your ears is much smaller – no more than a few hundred kilobytes per second. Your fingertips and other parts of your anatomy require even less of a data pipe.

In other words, we could send back everything a human could sense with a telemetry channel of, say, 10 megabytes per second. This is roughly the data rate you’ll soon be getting off a blue-ray disk. It’s not trivial to send data at this rate from star to star, but it’s a lot easier than sending ourselves.

Sending even the tiniest probe to a nearby star is a mammoth undertaking, one whose demands we’re nowhere near being able to meet. But it’s also clear that a robotic probe carrying the kind of remote sensing technologies Seth is talking about is a more attainable goal, for the near term, at least, than a crewed mission requiring life support over a period measured in decades if not longer. Throw nanotechnology into the mix and we could be talking about pushing tiny probes with assemblers that can create the needed facilities from asteroid debris upon arrival. Space-based lasers could supply the propulsion.

My hunch is that both outcomes are likely, with human missions obviously emerging later as propulsion technologies give us new options for getting there quicker. I’m also a believer in the Freeman Dyson notion that deep space exploration is not likely to happen as a result of massive government programs, but rather in the fashion of oceanic discovery in the 17th and 18th centuries. Yes, government-sponsored voyages opened up new territories (and let’s not forget Cook in the Pacific, working off Royal Society funding) but doughty bands of colonists driven by their own agendas played a huge role and, in doing so, re-defined the relationship between liberty and frontiers.

A Slow Scenario to Centauri

Here’s a slow scenario, just one of many: A culture capable of building space habitats and terraforming planets moves ever further into the Edgeworth/Kuiper Belt, harvesting resources and gaining expertise. Over a period of thousands of years, it moves deeply into the Oort Cloud and eventually to its outer edges, where the boundaries between the stellar debris of our own Sun and that of the Centauri stars may become indistinct. We find ourselves moving across the interstellar gulf in a series of small steps, an evolutionarily transformed spacefaring race.

It’s just a scenario. Faster is obviously better, but one way or another, a human presence in interstellar space seems as inevitable to me as tomorrow’s sunrise. And think of the reality shows it will provide the stay-at-homes! They’ll be watching people doing what Captain Cook said he would do, going not only “… farther than any man has been before me, but as far as I think it is possible for a man to go.”

Comments on this entry are closed.

  • James M. Essig January 16, 2009, 16:54

    Hi Paul;

    I have to agree that human presense in interstellar space will occur.

    Even in the event that FTL travel proves intractable, we still have the value of C, the Lorentz transformation factors, and the possibility of essentially limitless life span through medical intervention on our side.

    In the event that C is an unsurmountable limit, we can still relish in the fact that for ship board travelers, the speed limit of an infinite number of lightyears/second holds for the ships reference frame.

    Perhaps at some future distant time frame, we can slow time down within our stationary habitats inorder to match the high gamma factors of any ultrarelativistic interstellar or intergalactic manned juorneys. Perhaps somehow minipulating any existent chronons, which are particle like fundamental units of time according to some quantum gravity theories, could permit the slowage of time for stationary (with respect to the interstellar/intergalactic background) human habitats.

    If we manage only 0.1 C atmost over the next few centuries, that can get us out to 30 LYs from Earth and enable us to set up shop on perhaps hundreds of extrasolar planets and planetary moons. I think it is indeed “possible for a man to go.”



  • Dave Moore January 16, 2009, 17:06

    In a paper I presented at CONTACT, I looked into this scenario of slow colonization of the Kuiper belt and then the Oort cloud as a prerequisite to jumping interstellar distances.
    I looked at several interstellar propulsion scenarios from “Extraterrestrials, where are they?” by Zuckerman and Hart, and they all came up with a power requirements that clustered around the 100 Terawatt level. (These are 0.1c vessels)

    This is one hundred times our total power production at the moment and a million times the requirement for a nuclear powered Mars vessel (100 MW), which is a stretch with our current technology.

    At a 2% growth rate, our energy production increases by a factor of 10 every 116 years. At a 1% growth rate it is every 232 years.

    If we assume the ratio of the energy requirement of an interstellar vessel to the civilization that produces it is about the same as the ratio of our current energy production to the aforementioned nuclear Mars vessel, then at a 2% average energy growth rate an interstellar vessel would be built around about 2700 AD. If our energy growth rate is only 1%, then the interstellar vessel wouldn’t be ready until 3400 AD.

    Incidentally, there are already indications that even if we curtail or CO2 production, the waste heat of our growing energy production will be sufficient to overheat the Earth. A civilization confined to Earth is never going to produce anything like a million times more energy than we do now, so colonization of the solar system is a must if we are going to develop interstellar travel.

  • Adam January 16, 2009, 17:09

    If the human frame proves uploadable then in energy terms going as software to be implemented at destination makes the most sense. Shostak is right on that point. I’m agnostic on the issue – I don’t agree with Stuart Hameroff that it’ll never happen, but nor do I agree that it’s all classic computing and there’s nothing quantum going on. If travelling around at lightspeed proves possible then it’s preferable to slow-ships and similar time-consuming options – better to be beamed as software than wait millennia. On arrival a smart-matter android body should make a decent facsimile of the human frame, unless body-printing is much easier than it seems presently.

    Of course there’s the issue of what happens to the copy who stays behind…

  • Kenneth Harmon January 16, 2009, 19:31

    Hi Paul,

    Perhaps we have to start to differentiate between travel to Alpha Centauri which may be possible in the next ~100 years and everything else. Of course, human travel to the Alpha Centauri system is dependent first and foremost on there being something interesting to travel to. Assuming that we find planets in the Alpha Centauri System then the question becomes other then being the nearest known star system to our own for the next ~20,000 years are there other factors that may make a trip to the Alpha Centauri System more like a very long interplanetary trip then an interstellar one. Perhaps, we have to come up with some sort of new operating pardigm that defines Alpha Centauri as being within the “interplanetary zone” of Sol/ Terra.
    This is more then symmantics. There is enough emerging scientific data to indicate that while Alpha Centauri is cleartly interstellar in distance from Sol/Terra we are close enough to each other that traveling in the “local travel enviornment” between us is going to be substantially different then traveling from say Sol/Terra to a star system ~10 Light years from Sol/Terra. In essence, and for reasons other then just plain distance, traveling to Alpha Centauri may be marginally viable in the relative near term while traveling much beyond Alpha Centauri may be a much more challenging and longer term project. It seems that there are many people who assume that if humans can travel to Alpha Centuari then interstellar travel is now viable and we can go anywhere within at least a 50-100 Light year radius of Sol/Terra. This may not be the case and it is not just because of distance factors/travel times.


  • kurt9 January 16, 2009, 19:50

    I think Hameroff’s quantum theory of human cognition is a red herring. Regardless of whether cognition is quantum or classical process, it is still based on the arrangement of atoms and molecules that make up the human brain. If you recreate this arrangement of atoms and molecules, you “recreate” the person.

    If Hameroff is right, then you will not be able to create A.I. using classical computation. But you will certainly be able to create it using quantum computers. There are several start-up companies developing quantum computers. At some point in the near future, quantum computers will be sold in the marketplace just like classical computers are today.

  • Administrator January 16, 2009, 20:22

    kurt9, I don’t know anything about Hameroff. Where should I start to get an idea about what he’s saying? Any particular papers or books?

  • John Hunt January 16, 2009, 20:39

    they all came up with a power requirements that clustered around the 100 Terawatt level.

    I’ve got to imagine that these were addressing full-sized craft with living aliens (i.e. considerable mass). If we set aside those assumptions and go with Adam’s bodies-as-software or the frozen embryo approach then the 100 TW requirement become unnecessary. If advanced civilizations could master either approach then, it seems to me, that this would be the most efficient way of colonizing the galaxy. So for me power requirements don’t negate the question of “Where are they?”

    Right now we are able to accelerate gold atoms to very close to the speed of light. I once calculated what that would be equivalent to in carbon atoms accelerated to 0.1c. I believe that these machines are working in the 10s of MW level. I did this to see if it was possible to shoot a nanofactory on an interstellar mission. It turned out that it came to 410,000,000 carbon atoms. I think that that should be more than sufficient. Obviously surviving space dust, course correction, and deceleration are non-trivial issues. :)

  • Dave Moore January 16, 2009, 22:12

    One other thought. An obvious interstellar target for any Kuiperbelt/Oort cloud civilization would be Epsilon Eridani. It’s 10 ly away and has one hundred times the cometary mass of our system as well as 2 asteroid belts. That’s rich pickings.

  • Pete January 17, 2009, 0:01

    Don’t forget that we can also start talking about better astronauts.
    Progress in the life sciences is substantial and happening very fast. We will be able to engineer bodies that can live in space without structural failure, live much longer than at present and be much more repairable. Throw in nanotechnology and the revolution in materials that is coming and some humans will be able to go cosmic.
    I guess I could be satisfied if New Horizons is the last cool mission for my lifetime, given the economy and how out of it so many people seem to be.

  • David January 17, 2009, 1:59

    Hi Paul
    Hameroff is a long time collberator with Penrose on Conscioussness. I can refere youb to Penroses books but I dont know what Hameroff has written on his own Emporers New Mind was Penrose. I do think Tipler would agree with Kurt 9

    I agree humans will travel on interstellar missions in the distant future wither by solving th eengineering problem of sublight or the pysicas problem of FTL

    I am most interested in near term and that would be unmanned and very small or nanotech pushed by a laser

    Here is my question:
    Assume we build a very small probe say a gram incorporated into a very think sail how much laser power would we need to get it to 0.1 c?

    How far are we from that energy?

  • Ronald January 17, 2009, 4:24

    Small correction: 100 TW is not 100x our present human energy production/consumption (which is about 15 TW), but ‘only’ about 6 to 7 times.

    And 100 TW is most probably a calculation for manned travel, a small unmanned probe (1 ton range) would take only a (very) small fraction of that. And these could be spit out by a laser installation (either fusion powered on the moon or solar powered in space) in series.

    Robotic probe interstellar exploration could be very feasible from an energy investment point of view, once we master nuclear fusion. I agree with Kenneth Harmon, James Essig and others, that ultimately it is all a matter of incentive and priority (besides some ongoing technological development), not technical (im)possibility.

    Then again, we could question how much advantage that would offer us over, say, a good telescopic arrangement at the sun’s focal point.

    What a pity we are not part of a wide binary of solar stars, like Zeta Reticuli or 16 Cygni. What an incentive that would create (provided both components had terrestrial planets).

  • Tibor January 17, 2009, 7:19

    I think with this discussion we touch naturally the question about the further evolution of humans. Will we still be the same in two thousand years as today? Will be there a new humanlike species evolving during the colonization of the Solar System? I think e.g. on the “Ousters” in Dan Simmons Hyperion-Saga. Is the cyborg era coming? Or will be a coexistence of all/several of the possible ways?

    As Peter Ward writes in a brand new SciAm article: “Over the past 10.000 years humans evolved as much as 100 times faster than at any other time”.

    His offerings for the future:

    In short, humanity’s future could take one of several routes, assuming we do not go extinct:

    Stasis. We largely stay as we are now, with minor tweaks, mainly as races merge.

    Speciation. A new human species evolves on either this planet or another.

    Symbiosis with machines. Integration of machines and human brains produces a collective intelligence that may or may not retain the qualities we now recognize as human.

    Quo vadis Homo futuris?

    Here the link to the online-version of Ward’s article.

    My favourite is to remain human and I am with Paul Titze saying that “If there’s a mountain to climb, someone will climb it”.

  • James M. Essig January 17, 2009, 17:10

    Hi Adam;

    I rather like your reference to the idea of beaming a ship, transport, and/or a person’s body and brain in the form of bosonic mattergy.

    Obviously, there is the usual idea of breaking the person’s body down into electromagnetic energy then beaming it to subsequentially have it re-assembled over a stellar or galactic scale distance.

    Perhaps breaking the ship, transport, and/or a person’s body down into gravitons or gravity waves could be another way in which a persons identity could be transmitted.

    Note that the force of gravity, was the first force to branch of from the gravatic-strong-electroweak super force or super-gravity force during the first symmetry breaking event that occurred during the Big Bang. Also, gravitation seems to be the primary force by which all known and still theoretical particles interact within our universe and perhaps within our entire multiverse. These still theoretical partilcles include the supersymmetric mattergy particles as well as socalled mirror matter or shadow matter.

    The point that I am trying to convey is that perhaps gravitational radiation could be the perfect medium in which to transmit someones conscious identity after the physical underpinnings of such identies or parallell subsisting mattery to which the conscious identity would be attached, even if not dependant on matter for its existence, would be broken down into, and beamed in the form of, gravitational energy.

    If at some level, all individual particles are distinguishable, an idea involving hidden quantum variable perhaps or otherwise which is an anathema to modern quantum mechanicists, then perhaps merely assembling a body which is identical to that of a given human’s body on Earth even if the quantum mechanical information of the body would be quantum mechanically teleported with perfect fidelity, might not result in the transportation of the actual personality and/or for lack of a better word soul, of the person back on Earth.

    However, breaking the persons body down into gravitational energy might circumvent this problem since gravitational energy is a more, for lack of better word, primitive force, being that it was the first force to branch off from the superforce and also since gravitational energy, fields, and radiation is related to the very nature of curved space time. Perhaps psychodynamic elements or aspects of the human conscious states in this life are instilled in a somehow differentiatable unique mattergy.



  • Adam January 17, 2009, 19:57

    Hi Jim

    I incline more to the view that information is more fundamental and that the substrate is less important. But I think our physics is still too primitive to know one way or the other.

  • James M. Essig January 17, 2009, 20:51

    Hi Adam;

    Thanks for the above response.

    I have from time to time had the tendancy to reify abstract mathematical and logical entities in a manner in which Plato did in his ancient theories of Eternal Forms. The idea that such trancendent entities might exist as essence wise reified forms intrigues me. If it turns out that information is more fundamental and the substrate is less important, that would be good news for me.



  • Paul Hughes January 18, 2009, 3:54

    Hi Paul,

    My comment here is in response to your last two posts, which tie nicely together. I also like that your readers and yourself have considered nanotechnology, and the potential for “uploaded” minds to help make the journey. Here’s my take:

    Within the next 50 years we are likely to finally see some kind of bootstrapping intelligence take hold. This event will be the single most important event in the history of evolution, simply because a greater-than-human intelligence will be able to increase its own intelligence at an ever faster rate. Regardless of whether functionalism or physicalism is true, nanotechnology would allow us to increase the speed, density and functionality of current human brains. Whether this H+ intelligence is us (Intelligence Augmentation) or AI (Artificial Intelligence) is doesn’t matter for this argument.

    One radical intelligence increase enters the picture, the exponential advancement of space faring technologies should happen just as rapidly. Once the basic regenerative and self-sufficient space-faring systems for making anything from base space materials (asteroid, Oort and Kuiper materials), I can’t imagine why there would not be a myriads of “ships” of various kinds traveling to every “interesting” star/planetary system discovered the ever increasing “telescopes” that come on line. Whether these “ships” are capable of FTL or not, shouldn’t change this basic scenario.

    Personally I think something like Alcubierre’s warp drive or some other loophole to c will be found by this Hyper-intelligences before too long.

    Just my two cents on what is bound to be a VERY exciting time for exoplanetary astronomy in the coming years, no matter how conservative the technological outcome will be.

  • Shaun Steenkamp January 18, 2009, 23:06

    Why bother teleporting a human to a distant star system when you can simply beam back the required information from those places and have people “plugged” into the data stream. Since it is your brain is processing the information from your senses, it’s not your eyes that see, or your fingers that feel, it’s all in your brain. Naturally from this, if you could stimulate those areas of your brain that receive and process this input with technology, it would be as good as being in that distant system.

    I am pretty sure our ability to manipulate a human brain will be far more advanced by the time we can teleport people across the planet, let alone across interstellar distances.

  • ljk January 19, 2009, 10:31

    Why do we continue on this paradigm of big starships full of
    organic (namely human) crews operating it when we live in
    an age already conducting great computer and other technological

    Back when von Braun was planning manned missions to the Moon
    and Mars, his spaceships were full of dozens of men (and yes,
    they were men, no women allowed) performing tasks that made
    sense in his era when computers were the size of rooms and could
    do little more than calculate big numbers. They did not even
    consider sending automated probes to those worlds first because
    the foresight and technology was not there.

    Of course the reality became that robot probes were first to visit
    other worlds and humans only went to the Moon in small numbers
    and at great expense for mainly geopolitical reasons. This is still
    the case with space exploration as machines are overall better
    and – most importantly – still cheaper than sending humans out

    So why are we still going on with the 1950-60s Star Trek way of
    thinking about exploring other star systems? The main and likely
    ONLY reason we will ever send humans to Alpha Centauri is
    because we are still around in our current form and we need to
    get off Earth in a hurry for our survival. Of course another reason
    could be a group of people disatisfied with the way things are going
    here and want to live life their own way in a place that Earth
    authorities or society cannot reach them.

    But if you want to EXPLORE other star systems, then using machines
    is the way to go. Imagine what we will have 50 to 100 years from
    now in terms of AI, to say nothing of propulsion technology. Does
    it not make more sense to send a largely self-sufficient machine
    probe into the galactic neighborhood rather than a group of humans
    who will need all sorts of resources just to survive the trip.

    Regarding the “beaming” of a human mind to a destination system
    and have an Artilect waiting at the other end to reconstitute them in
    an android body – android in this case meaning its intent of a robot
    in human form – even if one did bother with so many extra steps to
    put a person out there (again, why other than survival, and if you
    already have the proper machines there, how does that help in
    terms of exploring the alien star system?), why chose to look and
    be like a human when there are probably far more efficient and
    interesting different forms to be?

    While I don’t want to see going off into fantasy land and having
    nothing good come of our ideas for interstellar travel and exploration,
    I worry that being mired in these dated paradigms will also bog us
    down from reaching another star any time soon. If we focus on
    fast machines with AI, then we could have a probe to AC on its way
    well before the end of the 21st Century. That would be a very nice
    gift to our children.

    If we keep trying to build the Starship Enterprise, then starships will
    remain film fantasies for centuries to come.

  • ljk March 24, 2009, 18:32

    Confessions Of An Alien Hunter

    By Michael Schirber

    for Astrobiology Magazine

    Moffett Field CA (SPX) Mar 24, 2009

    The search for extraterrestrial intelligence, or SETI, turns 50 years old this year. By scanning the cosmic radio dial, it has forged a scientific beachhead into the mystery of whether we are alone in the universe. One of its main disciples has written a book chronicling the history and offering an apologia as to why it is a worthy cause.

    As senior astronomer at the SETI Institute, Seth Shostak spends a good deal of his time publicly championing the search for extraterrestrial intelligence. He writes popular articles, gives presentations and even offers technical advice on movie sets (showing Keanu Reeves, for example, how to write the Greek letter “mu” on a blackboard).

    In his new book Confessions of an Alien Hunter: A Scientist’s Search for Extraterrestrial Intelligence, Shostak provides an insider’s account of the SETI universe.

    Shostak defends his choice of work from detractors that would say he and his companions are tilting at windmills. He is neither bitter nor strident – instead he weighs the opposing viewpoints very carefully (sometimes obscuring his own convictions).

    FUll article here:


  • ljk April 8, 2009, 13:34

    Interview with Seth Shostak in relation to his new book: