Alternate means to leaving gravity well, as opposed to launches

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Cretin42, Oct 28, 2001.

  1. [f] Registered Senior Member

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    wet1

    I don't think Teg was at all talking about usaing the moon as an anchor point... the discussion so far has talked about a number of ideas, not all of which were the "big tower - asteroid anchor" idea...

    I think (from simply reading) that he means that the moon would just be a good base.... with very low gravity launching vehicles would be easier.

    which doesnt exactly account for getting fuel, or payloads to the moon, which is basically what the problem is, how to get things from earth to orbit.... more efficiently
     
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  3. wet1 Wanderer Registered Senior Member

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    I quite agree with Teg that a moon base would be the way to go. A place for gathering resocures, doing astromincal work, and putting a fine edge on our present level of technology.

    As [f] made mention it is getting there that is the problem. (with equipment and supplies)

    Once there it would merely be a matter of setting up "camp" and then proceeding with the business at hand.
     
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  5. bruce walthers Registered Member

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    take as little as possible and get your materials from space, moon, asteroids etc. how much would it cost to get 10 tons of rock to the moon versus mining it there
     
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  7. Mandrax Registered Member

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    How to get there...

    I agree that the a solid moonbase is probably our ticket for further space exploration: Raw materials, Low gravity.

    Most of the proposes exotic transport solutions, whether it be guns, rockets, (s)ramjets, ion/electro motors, thethers, beanstalks etc. simply are more possible and cheaper to build on the moon.

    While the initial costs for a fully fledged industrial moonbase are VERY high it would pay-off as the moonbase starts to support itselve and no longer material from earth needs to be send in, the launch costs for further exploration will become much cheaper there

    So Instead of spending Billions in the development of high tec efficient new technology we could also choose to spend our billions on crude BIG sluggish but effective russian rockets to get there and then start saving.

    If we choose high tec, I think we should go for the electrodynamic thether solution and have a rotovator round the moon

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  8. ImaHamster2 Registered Senior Member

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  9. anim8er Registered Senior Member

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    The big gun.

    The multi-stage gun mentioned was the German V-3. It was built but never completed or worked properly.

    I've heard of another big gun approach using liquid or gas propellent. The problem with guns is that the "push" only lasts as long as it takes for the fuel to burn. For explosives, that's a very short time. By putting your propellent in a long pipeline, it takes longer for it to be consumed. You also provide a larger amount of propellent that way as well. Then you can use a longer barrel backed up by that longer sustained push as the fuel is consumed in the "pipeline" resivoir. I saw this in PopSci or other source.
     
  10. anim8er Registered Senior Member

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    Mercury used in anti-gravity designs.

    I would like to hear more about the experiment in sending an alternating current through mercury.

    About 10 years ago someone mentioned to me mercury in relation to UFO or anti-gravity propulsion system. This person explained nothing, but just put forth a relationship. The previously mentioned experiment is the only time I've heard anything else on the subject.

    Some people have suggested, but have not properly explained, "anti-gravity" devices using gyroscopes. I kind of put 2 and 2 together and came up with the following scenerio:

    What if you take a torroid chamber (donut) filled with liquid mercury. Being a metal, you can use electromagnets to force the liquid mercury to spin inside this tube. What happens to the gyroscopic force vector if the gyroscope is a liquid? Perhaps nothing more than generate heat, but an interesting experiment I would think.

    What ever happened to those electric generation plants that used liquid metal? (Liquid sulfur was it?)
     
  11. Gifted World Wanderer Registered Senior Member

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    The murcury thing works with any superconductor. Teh problem is that the weight reduction is somewhere around 2%, far too little to be of use. If the force can be inceased somehow, it cousl prove useful.

    The main problem(which is not a problem) is that the payload has to be hardened to withstand the force of the acceleration. The acceleration lasts as long as there is enoug hpressure behind the projectile. The calculations preformed showed that a 1m gun can fore a 4,000lb projectile. Think of a 5m gun...

    The moon, while only having 1/6g, is still not practal. I posted some ideas under the thread "Private Space Initiative." One of those was to use a suitably sized asteriod AS the ship. It would be simple, I think, to pressurize caves and tunnels cut in the rock. Then all we need is an engine, if you want to go somewhere.
     
  12. Dinosaur Rational Skeptic Valued Senior Member

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    No matter how it is done, getting humans and building materials off the earth and into space in large quantities requires incredible amounts of energy. Any approach to the problem must work solve the energy problem.

    Hydrogen fusion is likely to be the only source of such energy. Fission is not feasible due to the lack of sufficient fissionable materials. Hydrogen is the most plentiful material in the universe. Jupiter contains incredible amounts of it.

    We need to develop fusion technology, which might never be feasible outside of the interior of a star. Assuming it is possible, we then need to develop the technology to build hydrogen harvesting and fusion facilities on Jupiter. Using controlled hydrogen fusion for energy, launch containers of liquid hydrogen off of Jupiter and send to Earth or Earth orbit.

    BTW: For incredible amounts of energy, hydrogen fuel cells and other chemical processes are not sufficient. There is not enough oxygen or other chemicals. Hydrogen fusion is the only process for which there is sufficient fuel.

    An interesting possibility is to make an entire planet into a space ship. Hollow it out, fill it with hydrogen at pressures and temperatures sufficient for fusion. With nozzle like holes at say the South pole, the entire planet acts like a rocket. Replenish the hydrogen fuel from vast clouds of hydrogen found in most galaxies. Or perhaps replenish from other Jupiter like planets.

    While small scale controlled hydrogen fusion might not ever be possible, we might be able to develop the technology of large scale fusion. Containing hydrogen at millions of degrees and incredible pressures in the small quantities required for a power plant presents some formidable problems. It might be easier to develop the technology to to contain huge amounts in the interior of a planet.

    Consider the ratio of surface area to volume as the volume increases. The larger the volume the smaller the ratio. Heat loss is related to surface area. Per unit of volume, it is easier to keep a big object hot than a small one.
     
  13. Jthomas Registered Member

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    Gifted and anim8er... I think that the weight reduction of superconductors is different from that of the "mercury" experiments. Or, at least what they are looking at is. The superconductor change is a levitation effect from an opposing force. The mercury device is actually looking for an effective reduction in mass or change in the local G-field, but not an opposing field (unless you invoke torsion arguments). While the superconductor effect is well documented, there is no current evidence that the mercury devices work. (Not that they dont, it just hasnt been documented or published).
     
  14. Brett Bellmore Registered Senior Member

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    While putting something in orbit requires a lot of energy, (Not incredible, it's not that much worse than a flight on the Concorde.) the problem is that doing it with rockets requires many times a lot of energy, because most of the energy goes to lifting the rocket and the fuel, and rockets aren't terribly efficient at using energy to create momentum.

    Since I was in the L-5 society back in the 70's, I've heard of lots of non-rocket ways of getting into space, most of which were feasible from the standpoint of physics. The Lofstrom "launch loop", for instance, and all the allied kinetic structures, which use the force from deflecting high speed projectiles to support a very tall structure, and accelerate a payload.

    Then there's magnetic launching. Yes, you actually could lauch a payload into orbit by using opposing magnets. The one that stayed on earth would have to be many kilometers in diameter, though, and it's field would overwhelm the Earth's magnetic field over a sizeable portion of a continent. Try getting the enviromental impact statement for that approved, not to mention the NIMBY (Not in MY backyard!) problem to overcome.

    You can lauch objects into orbit using a mass driver, from the Earth's surface. The acceleration path has to be maintained in vacum, with a really fast door at the end to let the payload out, and then slam shut again before the vacum was lost. And the payload would have to be really tough, to survive punching up through the atmosphere at mach 25. The bigger the payload, by the way, the lower the acceleration it's subjected to by the atmosphere. You could send manned payloads up that way, but the mass driver would have to be really long, and the payload really heavy. The "bang!" when that freight train smashes through the air would blow people's eardrums out for miles around, too, so you'd need a site that was unoccupied, and ideally had a tall mountain on the east coast of someplace, so that you could lauch above most of the atmosphere, out over water. Oh, and near the equator, too.

    A varient of this I thought up myself, (Though I'm not claiming that nobody else thought of it!) would be to use the "Strong pusher plate with a shock absorber" concept which was to be used in Project Orion, together with a ground based mass driver, which would shoot bombs at the vehicle, which would be propelled by those conventional explosions. Most of the energy could be provided by electricity to the mass driver, and the vehicle doesn't need to carry it's own fuel, so it can be quite small and light for the payload it carries. Likewise the mass driver can be relatively small, because it's launching much smaller bombs than the size of the vehicle, albiet very frequently.
     
  15. kmguru Staff Member

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    11,757
    How about a microwave beam to supply the energy, where the vehicle rides on that beam (converting energy to electric propulsion). Many small loads to space - that way you do not have to carry and lift fuel....
     
  16. wet1 Wanderer Registered Senior Member

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    The lightcraft experimental laser launch vehicle

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    *here*
     
  17. anim8er Registered Senior Member

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    I wonder what has happened in the last year and a half? Are they still testing the Lightcraft? Is it now top secret?
     
  18. wet1 Wanderer Registered Senior Member

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    I would imagine that the hold up is that they need better technology and funding to build a huge laser.
     
  19. kmguru Staff Member

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    Here is the diagram of my electric propulsion.

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  20. RawThinkTank Banned Banned

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    Wow, This old thread was a great reading.

    Combine the three ideas. Create the gun barrel and magnetic rail into single component. The first problem come to mind is the height of this barrel; the solution is to build this barrel into the ground as deep as possible or in the deepest mine or something natural like that. The barrel is also composted of magnetic propulsion. The first stage of the rocket uses the barrel to explode fuel and gain high velocities quickly along with this the magnets too propel the rocket at the same time. And just as the rocket nears to leave the barrel the second stage booster or scram jet starts its action. Any problems here ?
     
  21. jamesm Lost in thought Registered Senior Member

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    A note on the tether approach...

    The problem with the tether idea is that one cannot get something for nothing.
    Even if a tether were anchored to a very massive object (such as an asteroid) in
    geosynchronous orbit, the reaction from the mass being accelerated up the tether
    would eventually force the anchor into a decaying orbit.
    If left alone, the anchor would eventually enter the atmosphere, after winding 36000km of tether around the earth - not a pleasant scenario.

    One could counteract this by boosting the anchor back into the correct orbit, using
    exactly the same amount of energy as was used to accelerate your object up the
    tether (assuming no friction, air resistance etc). Your net gain would be 0 - you
    have put as much work into keeping the anchor in the correct position as you have
    saved by climbing into orbit.

    Add this to the enormous amount of energy spent in positioning the massive anchor
    in the first place, and you have not really gained anything at all.

    Sorry to be a killjoy on an otherwise imaginative idea...
     
  22. ElectricFetus Sanity going, going, gone Valued Senior Member

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  23. eburacum45 Valued Senior Member

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    Thanks, James, and yes, that is true of all tether launch systems, even the smaller and more practical rotating tether systems.

    However you are assuming that there is no inwards movement of mass; it may be that imports down to the Earth are economically viable- mined He3 from the Moon for instance-
    or if not, the the outward material can be balanced by simple ballast, perhaps talings from Moon mining operations.

    If you use a lot of downwards ballast in a tether lifting system, you can gain energy from that system; this is one way of extracting energy from the rings of Jupiter and Saturn-
    magnetic energy could be converted to electrical energy by flinging mass into those giant planets
    (until the rings are all gone anyway)
     

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