How do Starships stop?

Discussion in 'Trek Tech' started by Albertus, Nov 9, 2008.

  1. GodThingFormerly

    GodThingFormerly A Different Kind of Asshole

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    I don't know about "right", but it was certainly imaginative and based upon a very sound (for an aerospace engineer who specialized as a space vehicle dynamicist) understanding of quantum field theory and general relativity.

    No, the impulse engines are thrusting through the ship's center of mass, so any reverse thruster would have been placed on the leading edge of the saucer.

    Nobody connected with ST:TMP's production has ever made such a statement concerning Probert's impulse deflection crystal, which presumably functions by directionalizing gamma rays for optimum impulse thrust.

    He is presumably referring to the late physicist and LitSF writer Dr. Robert L. Forward.

    TGT
     
  2. Albertus

    Albertus Lieutenant Red Shirt

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    It was not my intention to insult anyone, and if Timo was insulted, then I of course offer my apologies.

    For someone castigating another on their manners in a thread, your patronising and peremptory reply is hardly an example to others.

    However, I did understand the point made. No mention in Trek of such a way of stopping a vessel in that manner, that I can remember, except perhaps in DS9: "Explorers"/ "Accession", and in ST:TVH.

    I doubt that such a solution would be very practical, or even possible, for a ship engaged in high speed impulse manouveres during a battle where velocities and vectors need to be altered rapidly.

    :techman:
     
  3. Cary L. Brown

    Cary L. Brown Rear Admiral Rear Admiral

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    Well, let's consider what's really being discussed... a field-effect that, under the right conditions (either when unenergized or when energized under other-than-propulsive conditions) effectively "clamps on" to the fabric of space/time. This device would provide what would seem, from a kinematic standpoint, like a set of brakes. It would provide drag... though not against any physical matter-based medium, but rather against space/time. It would act like a drag-chute, or like a fighter's airbrakes... or like an automobile's wheel-brakes. But without any matter-based interaction with anything.

    Since this is entirely hypothetical (we don't know how you could interact with space/time anyway, really) it's not inconceivable that this sort of "drag" effect might actually be MORE effective than a retro-thrust solution might be.

    Ultimately, since there's no actual physics to address (that we know of, at least) regarding any way of interacting with space/time in the manner with warp drive, or subspace-assisted impulse, or antigravity/artificial gravity, or any of the other various field-effect system that trek uses... the solution isn't really constrained, is it?

    The only real quibble I have with the "space/time drag" solution is that, other than that one episode of Voyager mentioned earlier, there's nothing in-fiction to support that. Of course, there's also nothing to contradict it... but I'm always edgy about inventing new concepts out of whole cloth like this.
     
  4. Robert Simmons

    Robert Simmons Commander Red Shirt

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    You turn off the projector.:eek::rolleyes:
     
  5. bintak

    bintak Lieutenant Commander Red Shirt

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    This is workable. It might not take the form of a drag brake, but more like the form of a "keel" which can function as a "centerboard" in the graviton soup of local masses. You'd have to combine it with the inertia flywheel effect, but why not? It violates nothing in physics. All that is required is some way to lens gravitation as a tractor force as a "drag" or "plane". You have justification in the "tractor" beam. This would just be the lensing effect on a more massive scale.
     
  6. Timo

    Timo Fleet Admiral Admiral

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    Oh, no damage done. And different people here simply have different posting styles. Some express mild feelings through strong language, others channel utter rage into fifteen-syllable technological terms... Live and let live, perhaps?

    Oh, that would be a solar sail - but the subspace drag chute would be different in a couple of key ways. Solar radiation is a very localized phenomenon, but subspace would be everywhere, much like there is tarmac beneath the wheels everywhere on the road so that it can be equally used for braking at all locations. Also, solar radiation is a known quantity, whereas subspace has unknown properties that can be assumed to be sufficient for efficient braking.

    Well, today's fighters maneuver exclusively by using drag forces, at very high speeds and accelerations and course deflections. Like Cary says, if subspace is "stiff" enough, it should theoretically allow for very tight turns - analogous to Batman throwing an anchor off the side of the Batmobile, hitting a sufficiently strong lamppost, and doing a 90-degree turn at 80 mph.

    The idea has the upside, though, that it doesn't require any new, unmentioned hardware: it would probably be done with existing warp or impulse engine subspace coils. And thus any commands aimed at stopping would be directed at warp or impulse engines anyway. Kirk or Picard wouldn't go technical and say "route reverse current in impulse coils so that they grip subspace in a motion-inhibiting manner", he'd say "impulse engines, full stop", even if the two expressions meant the very same thing. That is, if this were the normal way for these things to operate, and not some exotic emergency maneuver. But that's exactly what we want: a regular, normal explanation to the ability of the ships to stop movement far more easily than they start movement.

    Timo Saloniemi
     
  7. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    I hit on a simple enough solution a few years ago.

    Assume that warp/subspace fields are local distortions in spacetime such that effective speed of light within the field is higher than it is outside the field (which is the same as saying that the effective mass is lower, but with slightly different implications). Warp fields are what happens when the effective speed of light is not only higher, but is biased in a particular direction so all objects in the warp field are moving forward with respect to an outside of observer while at rest with respect to themselves. In other words, subspace fields are artificial or natural regions of space in which the rest state of an object within it is slightly different from the rest state of an object outside it.

    Which means all you have to do to stop the ship is turn the field off. Then the rest state of the ship returns to the rest state of local space wherever the ship happens to be, i.e. interstellar space or orbiting a planet or whatever. Now theoretically, since starships are built in orbit of planets and moons, the moment they turn on their subspace field for the first time, they already have a certain amount of momentum with respect to that planet. In interstellar space, then, the order "all stop" causes the impulse field to deactivate and the ship returns to its original rest state: coasting through space at, oh, nine or ten kilometers per second relative to its home planet (drifting, in other words). When it does this in orbit of a planet, it is now coasting at nine or ten kilometers per second relative to that planet; this is what is meant by "standard orbit:" It is whatever circular orbit the ship can achieve with its original non-distorted rest state.

    It requires no new hardware, just a little bit of new physics. "All stop" is what happens when you turn off whatever subspace field you're using (hence the "powering down" sound effects that invariably follow that order).
     
  8. Mister_Atoz

    Mister_Atoz Commander Red Shirt

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    Perhaps the shots of the new Enterprise provide an answer to this question, those large dropping sections of the warp nacelles just below what used to be the Bussard Colletors on other designs provide reverse thrust during Impulse flight, they certain look big enough to do the job and they look to be in the right place assuming the saucer section doesn't block them.
     
  9. bryce

    bryce Rear Admiral Rear Admiral

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    You mean space brakes.


    The ship doesn't stop...it stops the universe around it! :techman:
     
  10. Gep Malakai

    Gep Malakai Vice Admiral Admiral

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    In discussing warp core design with Probert, he mentioned that his intent with the deflection crystal was that it received the antimatter pumped up through the intermix shaft from slush tanks at the base of the secondary hull, and converted it into energy for the engines. I doubt it was intended to directionalize gamma rays, as the matter/antimatter reaction aspect of Probert's work didn't get thought through until Sternbach came onboard for TNG.
     
  11. Rick Sternbach

    Rick Sternbach Fleet Captain Fleet Captain

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    To drop out of warp, you just stop juicing the warp coils. There's so much "drag" in subspace that it isn't hard to coast to sublight. To slow down from sublight, though, there's a couple of ways, like reversing the order in which you juice the warp coils, where you extert a fractional reverse warp push, like "warp point five" (which we did on occasion); or you can flip the polarity, so to speak, of the impulse driver coils and thus cut down your velocity. In 24th century impulse engines, the exhaust doesn't do much, but the driver coils and the fields they create to push on the continuum do.

    Rick
    www.spacemodelsystems.com
     
  12. Timo

    Timo Fleet Admiral Admiral

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    Sometimes our heroes call for reversing the engines when wanting to stop. Sometimes they just order the ship to be stopped. Might be two ways of saying the same thing - or might be that "reversing" (either vectoring the jets, or reversing the coil pulsing sequence, or perhaps both) is a more aggressive and rapid way of doing it than the normal field shutdown is.

    But the field magic component of the sublight drives obviously plays an important role in this. How it does this may vary from situation to situation, or from ship to ship. Quite possibly Picard's ship uses a different combination of tricks than Kirk's ship did.

    Timo Saloniemi
     
  13. Bill Morris

    Bill Morris Commodore Commodore

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    I like Rick's answer, but another possibility is that impulse engines in effect create and eject virtual particles into space to move the ship forward and create and eject the respective antiparticles to impart braking force, resulting in not magic but a virtual-particle vacuum, which really would slow the ship down.

    A real-world example of the power of virtual particles is demonstrated by the Casimir effect.

    http://en.wikipedia.org/wiki/Casimir_effect

    In nanotech, researchers are now trying to devise ways of manipulating the Casimir effect, so far by just varying its strength on different parts of a surface by having differences in smoothness to create variation in masking out counterforce of virtual particles between two surfaces.
     
  14. Timo

    Timo Fleet Admiral Admiral

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    Any theory that deals with Trek braking has to explain why it seems to be so much easier to stop a ship than it is to accelerate her. Thus, a mere reversed impulse drive isn't a very good answer, regardless of whether it generates acceleration through rocketry or through magic fields.

    Some sort of asymmetry is preferable here - hence the idea of somehow coupling into a static subspace framework, rather than merely using the onboard resources and the homogeneous properties of real space.

    Timo Saloniemi
     
  15. Ronald Held

    Ronald Held Rear Admiral Rear Admiral

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    Rick's answer seems to be the best recent one.
     
  16. Cary L. Brown

    Cary L. Brown Rear Admiral Rear Admiral

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    Well, the problem with Rick's answer is that the word "impulse" isn't just a made-up word. It's a real, technical, scientific word with a real, technical, scientific meaning. And that meaning is so clear, so specific, and so unambiguous that there's no room for redefinition.

    If you want to say "sublight engines" the "field effect" idea is acceptable... but if you call them "impulse engines" then, BY DEFINITION, they are engines which produce propulsion through an impulse... that is, the application of a force over time.

    If you say "impulse" you can simply substitute "thrust" and it means, for all practical purposes, the same thing. That's not "treknobabble," that's REALITY.

    So "impulse engines" ... translation = "thrust engines"... have to be related to the generation of actual thrust.

    I could live with his definition... but only if these things weren't being called "impulse engines."
     
  17. Herkimer Jitty

    Herkimer Jitty Rear Admiral Rear Admiral

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    It could simply be a holdover term, like how the ships we're talking abotu aren't quite related to sea-fearing ships of old, and so on.
     
  18. Psion

    Psion Commodore Commodore

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    Cary, is there any reason the thrust or force applied over time can't be non-newtonian in impulse engines? That is, produced without tossing something out of a combustion chamber?
     
  19. Crazy Eddie

    Crazy Eddie Vice Admiral Admiral

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    Because thrust itself is a newtonian action and cannot be applied without an equal and opposite reaction. The subspace driver coils in impulse engines can be interpreted as adjusting the equation so that both the action and the reaction are of much greater magnitude to an outside observer as they are to anyone inside the ship (so in the ship's reference frame it accelerates at .3G while to an external observer it accelerates at a billion G) you still have a newtonian component of inertia behind it. The ship can only stop in one of two ways: by reversing thrust and stopping ("Reverse power!") or by cutting power to the driver coils ("Full stop!") or both (reverse thrust and stopping, cut driver coils in "Reverse power, full stop!") When you cut power to the driver coils, of course, the roaring .5C you just accumulated turns back into the crawling twenty meters per second you an everyone else in your ship experienced.
     
  20. CuttingEdge100

    CuttingEdge100 Commodore Commodore

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    The God Thing

    I didn't know he was an aerospace engineer...

    Actually it's not. The saucer when seperated has the impulse engines in the perfect spot. When connected the nozzles would have to be trimmed to prevent what would otherwise produce a strong nose down tendency.

    When connected the reverse thrust location right under the torpedo tube would be quite good.

    Of course, the fact that the ship has no reverse thruster on the saucer when a saucer seperation could happen is not a good design feature.