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Sizing Up the Daedalus Interstellar Spacecraft

Posted by CmdrTaco on from the oh-this-will-be-fine dept.

astroengine writes "How big would an interstellar spaceship need to be? New artwork of the British Interplanetary Society's 1970's Project Daedalus by the non-profit organization Tau Zero Foundation gives the impression that the fuel economy for a nuclear pulse propelled vehicle might be a bit steep."

32 of 191 comments (clear)

  1. Spaceship? by stjobe · · Score: 3, Insightful

    Wouldn't "space probe" be more accurate? I don't believe it was ever intended to be manned.

    --
    "Total destruction the only solution" - Bob Marley
    1. Re:Spaceship? by Z00L00K · · Score: 2

      And if it were to be manned it wouldn't be a return trip so to allow for a sufficient genetic variation the crew needs to be at least 1600 individuals.

      Otherwise the risk of genetic degradation would be too great.

      --
      If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
    2. Re:Spaceship? by geogob · · Score: 5, Funny

      But... I was told that 2 was enough?!

    3. Re:Spaceship? by Anonymous Coward · · Score: 2, Interesting

      Or you could start with a small female crew, and thousands of "genetic samples". (Semen and eggs)

    4. Re:Spaceship? by careysub · · Score: 4, Interesting

      And if it were to be manned it wouldn't be a return trip so to allow for a sufficient genetic variation the crew needs to be at least 1600 individuals.

      Otherwise the risk of genetic degradation would be too great.

      Depends on what "too great" means. The Hutterite community in North America, a closed religious community, was founded around 1700 with a founding population of about 400 that was already highly inter-related (compared to world-wide human genetic diversity) and has now increased to 50,000. Genetic studies do show a measurable penalty in fertility and fitness with this high level of inbreeding, but the community is doing quite well nevertheless.

      What is more there is evidence of major human populations developing from even smaller founder groups PLoS Biology, June 2005, On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas asserts that "Taken together, the analyses in this study suggest a recent founding of the New World Amerind-speaking peoples by a small population of effective size near 70"

      Now the lack of diversity in the immune system of the American Indians later led to an epidemiological calamity when diseases from the Old World were imported 10 or 15 millenia later, but this is an avoidable hazard for interstellar colonists.

      But the key difference with a space mission is that there is much we can do to avoid genetic disorders and promote genetic diversity:
      * Select colonists (or colonist couples) for genetic diversity,
      * Use sperm/ova banks to import gentic diversity,
      * Use genomic screening to screen out lethal genes (which can be applied in a number of ways).
      These techniques can make inbreeding problems go away entirely.

      --
      Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
  2. From the article: A major drawback by Suki+I · · Score: 3, Insightful

    Or maybe not so major of a drawback.

    Says it would zoom past Barnard's Star in 50 years at 12.5% the speed of light because it is not designed to go into orbit. So, it is just getting a quick look there and everyplace else it travels. By the time this thing could be built, sensor technology might be up to the task.

    --
    Home of The Suki Series
    1. Re:From the article: A major drawback by Onuma · · Score: 3, Funny

      We could just harpoon & tow-cable the leg of Barnard's Star as we swoop by...

      --
      What else can happen when an unstoppable force collides with an immovable object?
    2. Re:From the article: A major drawback by macson_g · · Score: 2

      And by the time it gets there the sensor technology could be so beefed up that we will get better data w/o leaving our cosy solar system.

  3. Think Positron Engine Drive by tyrione · · Score: 3, Informative
    WSU Positron lab: http://www.cmr.wsu.edu/facilities/webster_547

    W.M. Keck Lab

    This article and video explains their research: http://wsutoday.wsu.edu/pages/publications.asp?Action=Detail&PublicationID=14531&TypeID=1

    1. Re:Think Positron Engine Drive by wagnerrp · · Score: 4, Insightful

      Antimatter reactions are ridiculously energetic, with an energy density of some 90PJ/kg. The problem is that there is no known naturally occurring source of antimatter, we have to produce all that we want to use. That makes it nothing more than a battery technology. Add in the inefficiencies of antimatter production, and you're talking about energy requirements equivalent to centuries at our current global consumption rate just to get into orbit. Finding a way to densely store the stuff is just one of many very difficult problems that need to be solved.

    2. Re:Think Positron Engine Drive by kiwix · · Score: 2

      That makes it nothing more than a battery technology.

      Given that the huge majority of the weight of any spacecraft is taken up by the fuel, an efficient "battery technology" would be a major breakthrough. If your fuel has a high energy density, it means your spacecraft will be lighter, and therefore require less energy.

  4. Absurd by burisch_research · · Score: 2

    Oddly enough, I was reading up on possible interstellar probes just a few days ago.

    Anyway, getting to another star system is just simply such a huge task. Take for example Daedalus' design -- the economics of building such a vehicle today are such that even if we had the political willpower to do so, it would just cost so much that it would soak up our global economic output for a very long time, possibly centuries.

    If we were to just wait 100 years or so, I'd put money on new physics being discovered which would allow an interstellar mission to be constructed for a tiny fraction of the cost of Daedalus (or Icarus), be completed in a fraction of the time, and have enormously increased capabilities (e.g. stopping at the target star, making a return journey, or even carrying Astronauts).

    It's an interesting study, but totally impractical today. We need a better understanding of the universe before we should even give serious thought to attempting this -- it doesn't pass the back-of-the-envelope test.

    --
    char*f="char*f=%c%s%c;main(){printf(f,34,f,34);}";main(){printf(f,34,f,34);}
  5. Re:Space and Sails by Lumpy · · Score: 3, Insightful

    So then what do you do when you pass the heilopause and you no longer have a solar "wind"?

    Honestly a redesign using ion engines of today would make a different craft. Plus it would allow the craft to not just speed on by in a ballistic trajectory, but even start breaking and enter a orbit that would allow the craft to stay and radio back info.

    It can be electrically powered by Nuclear reactors, and as each one get's past it's 20 year lifespan you jettison it making the craft lighter. Ion engines already are producing impressive thrust for the age of the technology. An unmanned interstellar probe moving at 12% the speed of light, assuming it does not plow into something out there is a very feasible project and could gather scientific data the entire way. Although the Doppler effect on communications would be interesting. But research into really measuring time dilation could be done as well.

    Sadly, we are far more interested in killing each other. It's more important to fund the war machine than the thinking machine.

    --
    Do not look at laser with remaining good eye.
  6. Nuclear fission propulsion by AC-x · · Score: 2

    What about using nuclear fission propulsion like Project Orion? We already have the material and technology to make one if a way to launch without causing fallout and EMP disruption could be found.

    1. Re:Nuclear fission propulsion by stjobe · · Score: 2

      I don't know where you get your figures from, but according to the Wikipedia page for Specific Impulse, the ISP for an Orion-style drive is 10.000 to 100.000.

      --
      "Total destruction the only solution" - Bob Marley
    2. Re:Nuclear fission propulsion by stjobe · · Score: 2

      Bah, preview fail. The ISP for an Orion-style drive is 10.000 to 1.000.000.

      --
      "Total destruction the only solution" - Bob Marley
    3. Re:Nuclear fission propulsion by stjobe · · Score: 3, Interesting

      Freeman Dyson published a paper called "Interstellar Transport" (Physics Today, October 1968, p. 41–45) on how to build an Orion spaceship to get to Alpha Centauri, so yes, it could carry enough fuel for interstellar travel. Your other two points are correct though.

      --
      "Total destruction the only solution" - Bob Marley
  7. Buyer's remorse by paiute · · Score: 2

    The problem is that if one undertakes a huge project to build a big ass ship and it launches, one hundred years later the technology will have advanced so much that we will be able to build another one which is bigger and faster. A hundred years later, the same thing. So the original ship gets to where it was going only to find that several ships are already there.

    I dimly recall some science fiction works with this theme.

    --
    If Slashdot were chemistry it would look like this:Cadaverine
    1. Re:Buyer's remorse by cowboy76Spain · · Score: 4, Insightful

      Yeah... but building it will be one of the ways of improving such technology (and every other way of improving the technology costs money, too).

      --
      Why can't /. have a rich-text editor? Editing your own HTML is so XXth century.
    2. Re:Buyer's remorse by Targon · · Score: 2

      The effort to construct each new ship is in itself a learning experience. As a result, even though each new ship would be that much better, it would take far longer to try to skip generations. Taken another way, if Intel waited until they could make a 16MHz chip, they would have gone bankrupt, so making the 4.77MHz 8088 was well worth the investment. While these ships may not be commercial vehicles, the technology that emerges as a function of building each ship(due to R&D) can help other projects, and will help mitigate the costs.

      Now, you also have to consider that while 100 years may seem like nothing when you are looking at the complete flow of time, look at how far science and technology have come in the past 110 years, from the automobile becomming something common, to flight, to rockets and satellites, and then to landing on the moon. From that perspective, the past 100 years have been fairly eventful when it comes to science and technology. I fully expect that in the next 100 years, we WILL have bases on The Moon, and possibly Mars.

    3. Re:Buyer's remorse by captainpanic · · Score: 2

      So, you're saying that you should never start any projects with a steep learning curve, but instead just wait (and wait, and wait) until someone else starts, and then be the 2nd to step in.

      Bah. I disagree. There's always a chance that the 1st project is actually the good one... and that it's considered good enough.

  8. Re:Automation has a long long way to go by Sockatume · · Score: 3, Interesting

    I think you'll find that we can do that, if by "we" you mean the human race. IKAROS has passed Venus, and is still going strong.

    --
    No kidding!!! What do you say at this point?
  9. Daedalus class by rossdee · · Score: 5, Funny

    I thought the Daedalus incorporated a lot of Asgard technology, including Hyperdrive and site to site beaming ability. It would be very useful to have since it can go to other nearby galaxies (Like Pegasus)
    Heres some info: http://stargate.wikia.com/wiki/Daedalus

  10. Re:How many people? by sznupi · · Score: 2

    It looks like 99% of the room is used for tanks and engines.

    Rocket equation and physics in general is a bitch, isn't it? (that 99% is not much worse than with all our current launch vehicles)

    --
    One that hath name thou can not otter
  11. Re:Space and Sails by sznupi · · Score: 2

    You coast until getting into the heliosphere of another star (they move quite predictably) - you can even slow down like that! (with the help of stellar aerobraking? That would be some sight...)

    Sails (also of more active kind) probably have one monumental advantage: they should be fairly easily mass-produced (without swallowing half of GDP of the planet like TFA projects would / that's some solution to constant (it was pretty much always like that, don't kid yourself it will ever change much) lack of funds for research)

    --
    One that hath name thou can not otter
  12. Re:Space and Sails by Seumas · · Score: 2

    We can't even coax ourselves into going back to the moon. At this point, we might as well be contemplating inter-dimensional travel, for all it matters.

  13. I strongly disagree by captainpanic · · Score: 4, Insightful

    Oddly enough, I was reading up on possible interstellar probes just a few days ago.

    Anyway, getting to another star system is just simply such a huge task. Take for example Daedalus' design -- the economics of building such a vehicle today are such that even if we had the political willpower to do so, it would just cost so much that it would soak up our global economic output for a very long time, possibly centuries.

    If we were to just wait 100 years or so, I'd put money on new physics being discovered which would allow an interstellar mission to be constructed for a tiny fraction of the cost of Daedalus (or Icarus), be completed in a fraction of the time, and have enormously increased capabilities (e.g. stopping at the target star, making a return journey, or even carrying Astronauts).

    It's an interesting study, but totally impractical today. We need a better understanding of the universe before we should even give serious thought to attempting this -- it doesn't pass the back-of-the-envelope test.

    It's not completely absurd. The projects that mankind undertakes today are enormous (in fact, there are multiple things that are way more expensive or complicated than this Daedalus spaceship). Take for example the entire road system of the world, including all rural roads, cities, traffic lights, cars, trucks, and whatnot. It's been an enormous undertaking - yet we don't mind rebuilding it entirely every decade because we don't like bumpy old asphalt or old cars.

    The ISS, with a weight of nearly 400 tons, and measuring 50x100 meters shows how much is possible for a relatively small-scale human project. All our civil achievements show how much is possible for the large-scale human projects. We don't mind changing the entire surface of our planet.

    We humans look at cost/benefit estimates. If the costs are high, we don't mind, as long as the benefits are there.

    The problem therefore with the Daedalus is not that it's not possible. It is that it just does not have enough benefits for mankind to invest the time, effort and resources in it.

    1. Re:I strongly disagree by Nethemas+the+Great · · Score: 3, Insightful

      In singular perhaps, but not in aggregate. US DoD funding for one year dwarfs the ISS. I personally would rather invest in something that can pay dividends even if the payout is some distance off. The slaughter of man and the destruction of infrastructure doesn't fit that bill. Stop making swords, start making pens, and go put the savings to productive use.

      --
      Two of my imaginary friends reproduced once ... with negative results.
  14. Re:Space and Sails by Chrisq · · Score: 2

    So then what do you do when you pass the heilopause and you no longer have a solar "wind"?

    I half remember some proposal where a sail plane would spend decades in ever increasing elliptical orbits building up speed until it would change course and head off at some reasonable percentage of the speed of light.

  15. A 100 years may be too late! by AGMW · · Score: 2

    ... If we were to just wait 100 years or so ...

    There are (clever) people who think that there is a window of opportunity for such a large project and that at some point the ever-growing population of the Earth will be so large that _just feeding_ everyone will take ALL the economic output of the planet. At that point, assuming we still have democracies, no Government is going to get elected if their manifesto includes such items as restricting the budget for feeding people and increasing the budget for some off-world boondoggle.

    This doesn't seem unlikely to me (too be clear, it seems like a logical extension of what's happening now!). How long have we got? well interestingly, the figure of 100 years had been bandied about. That may well just be the _nice round number syndrome_, but at some point it may be too late. That would be very sad because then the human species is doomed.

    We really need to be thinking about getting off this rock sooner rather than later ...

    (Sorry about the underscores, but italics don't seem to be working!)

    --
    Eclectic beats from Leeds, UK
    handmadehands.co.uk
  16. Re:Space and Sails by stevelinton · · Score: 2

    Ion engines don't have a high enough specific impulse (equivalently exhaust velocity). They would need far too much fuel.

    Even a perfectly efficient fusion rocket (which we have no idea how to build) would need a pretty huge mass ratio to achieve a total delta-V of .25c (ie speed up to Daedalus' proposed top speed and then stop again).

    Antimatter rockets could work, if we could find a way to (a) build them (b) make enough antimatter and (c) store it.

    Ramjets woudl be lovely but (a) we have no idea how to get hydrogen (as opposed to deuterium or helium 3) to fuse in less than billions of years, and a ramjet would have to do it in a few microseconds and (b) the solat system is in the middle of a big bubble in which the interstellar gas is exceptionally thin.

    Photon or magnetic sails powered by "ambient" power -- ie starlight, solar wind, etc. do not get nearly enough boost before they have escaped from the star and are too far away from it.

    The remaining option is beam riders. We send a beam of momentum, carried by photons (laser beam) or matter in some form (a stream of small very rugged missiles launched by a magnetic cannon at say 0.5c might work). This lets you leave your engine at home, which means it can be very nig and solar powered. The probe needs some way of catching the momentum, probably a light-sail or magnetic trap of some kind (blast the missiles to plasma and bounce them off a magnetic field). Stopping is harder -- Forward proposed detaching part of sail and sending it on ahead as a mirror and then using the reflected laser beam to brake.

  17. Re:HOW DO I VIEW ALL COMMENTS WITH NEW SLASHDOT? by Fnkmaster · · Score: 3, Informative

    You switch to D1 instead of the stupid D2 discussion system by clicking on Account while on the main page. D1 actually lets you view more-or-less all the comments for most stories.

    Then fix up the D1 system by creating/editing userContent.css (assuming you are using Firefox) in your profile/chrome directory:

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