Slashdot stories can be listened to in audio form via an RSS feed, as read by our own robotic overlord.

 



Forgot your password?
typodupeerror
Sci-Fi Space Science

Using Fusion To Propel an Interstellar Probe 155

Posted by samzenpus
from the nukes-in-space dept.
astroengine writes "We've heard of nuclear pulse propulsion being the ideal way to travel through interstellar space, but what would such a system look like? In the 1970's, the British Interstellar Society's (BIS) Project Daedalus was conceived to fire pellets of fusion fuel out the rear of an interstellar space probe that were ignited using a powerful laser system. The 'pulsed inertial confinement fusion' wouldn't be 'vastly different from a conventional internal combustion engine, where small droplets of gasoline are injected into a combustion chamber and ignited,' says Richard Obousy, Project Leader and Co-Founder of Project Icarus. Now, building on the knowledge of Daedalus, the researchers of Project Icarus have prepared a nifty animation of a fusion pulse propulsion system in operation on the original Daedalus vehicle."
This discussion has been archived. No new comments can be posted.

Using Fusion To Propel an Interstellar Probe

Comments Filter:
  • Or fission (Score:3, Interesting)

    by the_humeister (922869) on Wednesday April 06, 2011 @10:17PM (#35740868)

    http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) [slashdot.org]">Project Orion from the 1950s

    • by Kozz (7764)

      Fixed URL.

    • Re:Or fission (Score:5, Interesting)

      by mirix (1649853) on Wednesday April 06, 2011 @11:01PM (#35741068)

      I read about this years ago, and also nuclear aircraft [wikimedia.org] more recently. a bit hazy on the rocket theory, but I was rather amazed they actually attempted airborne... the potential for fail is beyond ridiculous... like a B-52 doesn't make a big enough mess with just nuclear weapons [wikimedia.org], never mind a reactor on board...

      • by Sir_Lewk (967686)

        Fun fact: there are currently numerous nuclear reactors in orbit around the earth.

        No, not nuclear batteries. There are way way more of those.

        Nuclear Reactors.

      • by AmiMoJo (196126)

        Keep in mind that at the time it was a question of how much risk is acceptable to protect the US/USSR from total annihilation. The Russians actually flew some of their aircraft and irradiated the crews, but they were desperate. In the end ICBMs proved to be the better option so nuclear aircraft were abandoned.

      • by hey! (33014)

        Well, I think the reasons for looking at nuclear aircraft maybe weren't all so silly as having the biggest, baddest stick on the block, although no doubt that was part of the attraction. A nuclear powered aircraft could take off at the first hint of an emergency, and remain aloft indefinitely, randomly cruising the vast airspace of North America virtually untrackable by the Soviets until the order came to attack. Then they'd be able to strike any point on the globe from just about any other point on the

      • by GooberToo (74388)

        As a interesting bit of trivia, nuclear aircraft are the primary reason why we have modern IFR rules [wikipedia.org]. The aircraft required so much shielding, the pilots could barely see out of the aircraft. So to allow for safer operation, they started with some simple procedures used by submarines and it has evolved to what safely delivers you to the ground today.

      • by jgtg32a (1173373)
        You know what was hotter than a Nuclear Aircraft? A attack drone, that flies at mach 3 with a scram jet "fueled" by exposing its nuclear core directly to the atmosphere, and it carries 16 1MT nukes.

        http://www.merkle.com/pluto/pluto.html [merkle.com]
        • by wagnerrp (1305589)
          Just a minor point, but this was a ramjet, not a scramjet. While similar in basic operation, the scramjet has supersonic flow through the combustion chamber/heat exchanger, while a ramjet is subsonic. It would likely be very difficult to maintain supersonic flow through a heat exchanger. Beyond that, you simply can't get sufficient compression at Mach 3 for a scramjet to function.
    • by IrquiM (471313)
      Old news - Russia is starting to plan a new fission-spacecraft.
  • Unless we figure out something that allows us to beat light speed even the nearest star is 4 years + away.

    • Thanks to relativity / time dilation, you can get close w/o breaking it, and (at least to the passengers), it'll seem like a lot less time overall. Still more than four years to the nearest neighbor, but a lot less than the monster number of years it would take as we see it.

    • by Jamu (852752)
      If we beat light speed, I think we'll be having too much "fun" travelling backwards in time.
      • by Coren22 (1625475)

        Why do people say that so often? If we go 2 X c, do you somehow think that if we fly to Alpha Centauri and back we will arrive before we left? It is still 2 years there and back, so you will arrive 4 years later. Just because your light reaches the destination after you do, does not imply time travel.

        • If you can travel faster than c then relativity says that you can go back in time. It does not matter how you do it. We have a lot of data to say that relativity is correct. You must modify relativity as it stands if you want FTL and causality.
    • even the nearest star is 4 years + away.

      Don't bother telling them. People who think we'll be journeying to other star systems and colonizing them someday really have no appreciation of just how vast and empty space is. When I was a kid my ignorant teachers used to teach us that the next solar system was just beyond our own, and that one day we would be going there (along with cities on the moon, etc.). When I got older and began to learn from non-moronic sources, I realized just how silly that really was. Our fastest probes today take some 9 year

      • even if we were to come up with some incredible propulsion breakthroughs, it still wouldn't help all that much. If Einstein was right, near light speed is as good as it gets. And that would still make all but our closest galactic neighbors practically inaccessible.

        Space is vast and using conventional propulsion tech, you are correct.

        But it also would be looking at a bird and saying we'll never fly. Technology can greatly affect what is 'possible'.

        Einstein also agrees that worm holes are possible so faster than light travel *is* possible by his definition. You don't actually exceed the speed of light, but you get somewhere faster than the light would have by taking a shortcut.

        Are we anywhere near that sort of ability? of course not. But so far it isn't

      • by Gilmoure (18428)

        Will just have to make our own aliens. Who's up for some freaky body mods so they can settle and start an Ayn Rand asteroid settlement. Within a generation or two; totally alien.

        • by elrous0 (869638) *

          I actually think that is the more likely possibility. If humans are able to genetically mod themselves in the future, they could easily end up creating post-humans that are much more strange and bizarre than any alien we've ever conceived of.

      • by wagnerrp (1305589)
        Some estimates put the outer reaches of the oort cloud, and thus the limits of bodies orbiting our solar system, at the better part of a light year from the sun. So with our little home being over a light year and a half across, the next solar system just four light years away would be a short trip down the block.
    • Not quite so. We can't go faster than light, but with some energy we can make the travelling distance smaller, so we can get there in less than 4 years (on the traveler's reference frame).

      Relativity is funny like that.

  • Why Icarus? (Score:5, Insightful)

    by chihowa (366380) * on Wednesday April 06, 2011 @10:31PM (#35740944)

    I really don't get the fascination with naming space projects after a failed attempt at flight. If there's one thing Icarus didn't do, it was "[build] on the knowledge of Daedalus!"

    • If there's one thing Icarus didn't do, it was "[build] on the knowledge of Daedalus!"

      As I remember the story, Iccarus did build on the knowledge of Daedalus (who built his wings), and flew higher than Daedalus.

      • by drinkypoo (153816)

        Also, while immensely unfortunate for Icarus, the story is one of triumph for science. The next revision of the wings didn't utilize wax. Now we can fly to space.

    • by AmiMoJo (196126)

      Depends how you define "fail". His wings worked pretty well, too well in fact...

    • by RevWaldo (1186281)
      So, what are you trying to tell me here, little man? That you don't like Zep?

      .
    • by jgtg32a (1173373)
      It wasn't a failure, it worked just fine; just make sure the probe goes away from the sun and everything will be fine.
  • by bmo (77928) on Wednesday April 06, 2011 @10:52PM (#35741048)

    "Nukular" hysteria will kill it.

    Remember when we launched Cassini with a radioisotope thermo-electric generator?

    "OH GOD IT'S GOING TO SPLODE AND KILL EVERYONE!!!111ONE"

    Every time I see shit like that, I want to slap people.

    --
    BMO

  • Fusion would provide a higher specific impulse than fission - in theory. Due to the large weight of the laser systems and the fuel tanks though, it isn't clear that in a practical design a fission rocket wouldn't be better

    Its pretty easy to imagine a fission rocket that used it's fuel pretty efficiently, then used the waste products as reaction mass in an ion drive. . (you might even be able to use the fuel as a structural material before you burn it)

    If you are willing to use a solar system based drive lase

    • Two words: fuel availability.
      • Unless you are planning a to build a LOT of really big star ships, fuel cost isn't likely to be a big issue. Uranium is something like $50/Kg, so 10,000 tons (suitable for a comfortable sized spacecraft is only $50M, pretty insignificant.

        Mining uranium at your destination might be a big issue - not clear at that tech level how difficult it would be to mine metallic asteroids for fissionable materials.

        --- Joe Frisch

  • by Animats (122034) on Thursday April 07, 2011 @12:16AM (#35741398) Homepage

    40 years ago, the idea of triggering fusion with a laser seemed promising. That's what Lawrence Livermore's Nova laser was supposed to be for. But laser ignition didn't work as an energy source. [wikipedia.org]

    Maybe someday, but not yet.

  • http://en.wikipedia.org/wiki/NERVA

    'NERVA demonstrated that nuclear thermal rocket engines were a feasible and reliable tool for space exploration, and at the end of 1968 SNPO certified that the latest NERVA engine, the NRX/XE, met the requirements for a manned Mars mission. Although NERVA engines were built and tested as much as possible with flight-certified components and the engine was deemed ready for integration into a spacecraft, much of the U.S. space program was cancelled by the Nixon Administration

    • Is a better idea. For the idea using lasers, you need power to the lasers, and I think (ok, ok, i'm not a enginner) a constant impulse is better than one pulsed because the possible vibration (and failure modes, what happens if the pellet gets stuck?).
  • by Grapplebeam (1892878) on Thursday April 07, 2011 @12:45AM (#35741496)
    And they combine the knowledge from both Daedalus and Icarus, I'm guessing they'll call it Helios. Wild guess.
  • So, a really basic animation that practically anyone can do is worthy of a Slashdot story - why?

  • by RevWaldo (1186281) on Thursday April 07, 2011 @06:49AM (#35743064)
    They build a ship that can reach the nearest star in 100 years. Off it goes.

    25 years later, they build a ship that can make the journey in 50 years. Off it goes.

    74 and a half years later, they build a ship that can make the journey in a day.

    Hopefully there's no one in "suspended animation" or "space children" on the first two ships, otherwise they're gonna be pretty pissed off.

    This is why getting people to commit to the effort to build an interstellar probe is pretty much a non-starter. We're perfectly happy to wait for the "breakthrough breakthrough" thankyouverymuch.

    .
    • This is why getting people to commit to the effort to build an interstellar probe is pretty much a non-starter. We're perfectly happy to wait for the "breakthrough breakthrough" thankyouverymuch.

      Because everyone thinks like you. That's why nobody's ever moved off to a frontier, they'd rather wait for the airport to get built and fly there.

      Hey, wait a second...

    • no on is waiting because the tech isn't good enough to make it easy. if we had the tech and the economic might to get alpha centauri, even if it took 500 years, we'd have thousands of volunteers to make history like that

  • Technical term for "propulsion achieved by firing pellets from the rear".
  • priorities people

    petroleum funds ultraconservative wahhabi islam, coal gives us air pollution, fission?: fukushima, etc

    yes, fusion will have radioactive byproducts too, but not the 10,000 year half life variety (i believe it is a decade or two for the worst... tritium is it?)

    and yes i know the other standard answer: we already have fusion power, it's called the sun (solar panels... petroleum and coal even are fusion energy storage vectors, give or take a couple million years)

    and please don't give me the bou

  • The "aliens" use a fission-propelled starship; I believe Stephenson got the idea from project Daedalus.

    Great read, with the usual Stephenson caveat - you probably won't be happy with the ending.

  • Chevron nine... locked.

  • With luck, it will look like one of these designs (with the FTL engines hopefully added on soon after)

    Fusion Engines on a starship [startrekphase2media.com]

Physician: One upon whom we set our hopes when ill and our dogs when well. -- Ambrose Bierce

Working...