Interstellar and intergalactic travel

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Norsefire, Jan 4, 2008.

  1. phlogistician Banned Banned

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    Not according to the schematics I've seen;

    http://www.space.com/media/pdf/spc_lib_gdyson_preview.pdf

    check out the diagram on page 4.

    One single pusher plate. This thing, as proposed, could lift off, but not steer. At 200 tons, standard manouvering thrusters or retro rockets would not be able to orient the vehicle. It would be impossible, therefore, to stop. The only way it would work, was if it were a cube, and able to eject nukes in every direction.
     
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  3. Read-Only Valued Senior Member

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    Not necessarily. Only a slight, tiny angle change on the pusher plate would be necessary and even small steering jets could do the job slowly. No resistance to overcome, just inertia. So just a short burst would begin a very slow rotation about it's center axis allowing for re-pointing the nose.
     
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  5. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

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    Antimatter.
    That's your answer.
    The perfect Energy / mass efficiency.
    A few grams of the stuff could apparently get an unmanned probe to Mars in a month, compared to the 11 months of conventional rockets.

    The only issues are:

    (1) Production. At present production rates of artificial production it would roughly 2 billion years to produce just 1 gram of the stuff; It's said that all the production of artificial antimatter so far would light a single lightbulb for only a few minutes.
    (2) Storage. Current techniques can store antiprotons for roughly 10 seconds after production, and I don't think antihydrogen has ever been stored. And the storage container weighs a fair amount as well!

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    And then the main problem...
    Any fuel that has high-energy potential will have a military use far earlier than a scientific use. So as soon as anti-matter becomes available for scientific use / space-travel, it will most likely already be developed into weapons of global destruction.

    Hey ho!

    Ion propulsion is the most feasible "conventional means" at present, in my opinion. Granted it starts slow. But you can set the space-ship in motion long before you send people onto it (using conventional means). And given you're looking at 1000 years to travel the distances... a few years to get going won't make a huge difference.

    And then wormholes... but this needs exotic matter as well as some existing assumptions for wormhole feasibility to be proven.

    I guess we're stuck with interplanetary until then.

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  7. eburacum45 Valued Senior Member

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  8. phlogistician Banned Banned

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    Well, the schematics don't show a gimballed pusher plate, but I agree in principle. Your approach would allow for directional change, albeit slowly, and I guess once on the way to The Moon, or Mars, you have got plenty of time to orient the vehicle, but I have doubts about getting into orbit once Orion gets there. It would all have to be executed really accurately, as there is little wiggle room for error, especially considering the energy is in bursts. If the yield of the nukes could be dialed in as they were ejected, maybe that could give less quantised, and more variable thrust.

    Anyway, I don't think the concept was actually viable, the speed and frequency at which the nukes have to be ejected from the vehicle, to pass to the correct position beyond the pusher plate is problematic. The factor in gimballing the plate, and it's potential reaction speed (although simple brakes could be used to prevent some shock absorbers extending fully, I think that would be another tricky engineering task).
     
  9. Read-Only Valued Senior Member

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    Yes, personally I'm not real happy with the feasibility of the original thing anyway. It looks to me like something that a couple of engineers sketched out on the back of an envelope while on a coffee/tea break.

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    And from that point, someone else picked it up, wasted real money on it and somehow it became a "project" - for a while.

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  10. orcot Valued Senior Member

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    the most probable first stellar probe
    link

    from daedalus 54000 tons ship to orions 300 tons and now the starwisps 80 grams (altough their is a extra reusable space station).
    And it is by far the fastest daedalus would only reach 12%c orion a mere 5% and a starwisp 20%
     
  11. cosmictraveler Be kind to yourself always. Valued Senior Member

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    Even if this were to work just how can it transmit data back to the Earth?
     
  12. orcot Valued Senior Member

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    from the link
    and a correction a starwisp weights 1,80 kg

    These are the weights that we could possible speed up to such speeds and micronisation is the fastests growing science in these years.
     
  13. cosmictraveler Be kind to yourself always. Valued Senior Member

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    I agree, I thought there were some type of manuvering thrusters on it to allow it to turn. Looking at that image I can't see any. Thanks for posting it.

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  14. Read-Only Valued Senior Member

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    I would venture to say that there MUST be thrusters there somewhere. Any design that didn't allow for trimming would be the greatest engineering boondoggle of ALL time!

    No device can be so perfectly well aimed that it could travel millions of miles and arrive at a designated spot!!!! Besides, without the ability to maneuver, what could it possibly do in terms of observation? Just zoom by something at several hundred thousand miles per hour? That's as outrageous as expecting it to arrive at a predesignated set of coordinates that far from the starting point!!

    Absolutely none of that makes any sense at all.
     
  15. phlogistician Banned Banned

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    Well, that is my major problem with Orion, that the practical points never got thrashed out, but we had that loon who called himself 'ProjectOrion' (some guy called 'Wayne that Q is aware of) rattling on about it before.

    Here's a debunking I did of the ejection system;

    http://www.sciforums.com/showpost.php?p=718480&postcount=110

    To be honest, I have as much if not more issue with this, than with steering.
     
  16. eburacum45 Valued Senior Member

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    Steering is the same as with all rockets- point the ship in the right direction while accelerating and you will get where you want to go.

    The ejection system is a weak spot in the pusher plate concept; here is one solution I have found. This chap has made a series of well-thought-out models of Orion ships, depicting an alternate history where the Amerians and Soviets fight a war in deep space.
    http://rhysy.plexersoft.com/Deep Space Force Gallery/

    Here is an image of the pusher plate and trapdoor

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    As far as I can see, the 'trapdoor' doesn't close; instead it remains open, and a plume of plasma comes through with each firing, which is deflected by the conical shape of the spaceship above. When the shock absorbers reach their maximum compression, the delivery system in the centre makes contact with the plate and ejects another bomb package through.

    I'm not entirely sure that this is the best solution, but Freeman Dyson expected the plate itself to undergo minimal ablation - and the structures behind the plate would receive only a fraction of the ablation that the plate would receive. If well designed they should function well under such conditions.
     
  17. eburacum45 Valued Senior Member

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    Another solution could be to lob the pulse units around the edge of the plate, and detonate them when they get to the midline using precision guidance technology. Three or more catapults (say) could operate in turn, poking around the plate only when it was time to throw another bomb.
     
    Last edited: Jan 13, 2008
  18. phlogistician Banned Banned

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    The ship would have to have the same coating as the shield, and there is going to have to be a trap door mechanism of some sort, because those nukes are being detonated at just 140metres from the ship, and you don't want any exposure to that.

    That said, we still have the problem of this mechanism opening and closing at the frequency of 1hz, and the nukes travelling at 140m/s.
     
  19. Norsefire Salam Shalom Salom Registered Senior Member

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    However, you guys are forgetting that even getting to Mars in a month is still too damn slow.

    Is it possible to get to Mars in under a week? That's really the only convenient time scale, and even then it's too much if we want to colonize the solar system.

    Communications! Even if we reached a star 60 light years away, we'd need to find some better form of communication between Earth and that star otherwise it will take 60 years to transmit a message, which is obviously inconvenient.
     
  20. Avatar smoking revolver Valued Senior Member

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    A month of travel ain't that bad, considering how long it once took to reach India or Americas.
    Currently we are using the equivalent of a space raft.

    Humm, we could use pidgeon mail...
     
  21. orcot Valued Senior Member

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    it took colombus 2,5 month to reach america
    It took him 8 months to report back. Now it happens instantly try that explaining to someone who doesn't know anything abouth phones

    But in the end your yust as likly to use a ??? to travel to mars in hours and make a direct call on your ???. As Colombus could have used a plane and cellphone. Your born a couple of centuries to early for that.
     
  22. Norsefire Salam Shalom Salom Registered Senior Member

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    Yes, but there is nothing faster than light, and as for communications that hinders it quite badly
     
  23. orcot Valued Senior Member

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    And no boat will ever reach the speed of sound, you would need a plane.

    If you believe that there ever was a big bang then you must agree that at one time all matter/energy was more or less on the same place and then it expanded in a gravity field most likly higher then the speed of light.

    Humanity does not stop even if we have to. Technological developments are sure to come, it would be scifi to predict them especially something as poorly understood as fasther then light travel.
     

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