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NASA Confirms The Plausibility of Reactionless Drives??!!
Ace of Spades HQ ^ | 8-1-2014 | Ace

Posted on 08/01/2014 4:13:21 PM PDT by servo1969

Let me geek out on you (I love science) and explain to you the science (I love science) and why this had previously been confined to the pages of science fiction (I am a nerd; and oh Dear Sweet Bunsen-Burner Lighting Lord, do I love science).

So it's a pretty firmly established principle that every act causes, and requires, an equal and opposite reaction.

If I understand this right (did I mention I love science?), this means that any space vessel will have to carry with it an enormous amount of reaction mass.

You can't -- we think, or thought -- just push energy out the backside of a spaceship and make it go voom. (Voom is a term that we who love science use.)

You have to actually impart momentum to physical mass -- a gas, for example. You spurt the gas out of the back of the spaceship. The gas is going backwards quickly, which makes the spaceship go forwards.

Without actually ejecting mass in the opposite direction you want the spaceship to go, we think -- or thought (those of us who think about science because, oh right, we love it) -- you have no propulsion at all.

So this means that the various spaceships you see in movies are all wrong. (All wrong is a scientific term.) A real spaceship should have tremendously large tanks of reaction mass, which it uses in flight to propel it. The proportion of "tank" to actual ship should be enormous -- the actual ship part of the ship would be tiny.

Basically a real spaceship would be an enormous series of gigantic tanks, with a tiny little cockpit/living space somewhere on it like a pimple. (Pimples are small oil-filled sacs in the epidermis -- That's science!)

Not only does this look goofy, thus destroying our dreams of sleek spaceships, but it imposes considerable, considerable engineering challenges on spaceship design, as the ship would be something like 90% reaction mass.

You'd have to carry around that much mass-- and when you tried to propel yourself, you'd have to accelerate that much mass, and of course all that mass doesn't wish to be propelled and will resist you. (We call that resistance-of-mass-to-acceleration "inertia" -- now there's some deep Science for ya.)

All told, it would be so, so much easier if we were disburdened of this very inconvenient law that only a mass being ejected from the rear of the ship could propel the ship forward.

This is why science fiction often postulates "reactionless drives." The term describes a hypothetical, fanciful drive system which does not require mass to be ejected from the ship, but instead just pumps out energy.

Or something. Writers are rarely detailed about it because it's just silly.

This is -- or was -- widely believed to be simply impossible and a very silly, if nonetheless pleasing, background conceit of science fiction.

Or science fantasy, really, when you take into account a reactionless drive is physically (or should I say physics-ally) impossible. (Did you see that? That was a science joke.)

But is it impossible?

Short answer: Yes, it's impossible.

Long answer: But maybe not.

Nasa is a major player in space science, so when a team from the agency this week presents evidence that "impossible" microwave thrusters seem to work, something strange is definitely going on. Either the results are completely wrong, or Nasa has confirmed a major breakthrough in space propulsion.

British scientist Roger Shawyer has been trying to interest people in his EmDrive for some years through his company SPR Ltd. Shawyer claims the EmDrive converts electric power into thrust, without the need for any propellant by bouncing microwaves around in a closed container. He has built a number of demonstration systems, but critics reject his relativity-based theory and insist that, according to the law of conservation of momentum, it cannot work.

...

[A] US scientist, Guido Fetta, has built his own propellant-less microwave thruster, and managed to persuade Nasa to test it out. The test results were presented on July 30 at the 50th Joint Propulsion Conference in Cleveland, Ohio. Astonishingly enough, they are positive.

Now I gotta tell you: Frankly, I think this is all an error, and it will soon be disproven. I think there's some artifact going on here, something no one is checking.

I think it is true, and will remain true, that you have to shoot propellant out your rear to go forward.

But this does have one nice effect:

You can now read science fiction stories postulating reactionless drives and consider them plausible, rather than fantasy.

For now.

Until they disprove it all.

Thanks to various members of the blog's I Love Science/I am a Nerd team, @conarticritic, @rdbrewer4, and @comradearthur.


TOPICS: Astronomy; Books/Literature; Education; Science
KEYWORDS: alcubierre; electrogravitics; electromagneticdrive; emdrive; eugenepodkletnov; eugenepodlekov; ftl; guidofetta; mdrive; microwave; microwaves; miguelalcubierre; nasa; newtonsthirdlaw; propellentlessdrive; rogershawyer; spaceexploration; stringtheory; superluminal
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To: chaosagent
Nonsense.

The New York Times isn't The Physical Review. Physicists knew [and have known since Newton] that the reaction isn't against the air, but against the walls of the combustion chamber; if it were otherwise, the thrust developed would diminish the instant the rocket left the ground, since your hypothetical [and nonsensical] "push" is would initially be against the ground, which is much more resistive than air.

61 posted on 08/02/2014 10:36:01 AM PDT by FredZarguna (Das ist nicht nur nicht richtig, es ist nicht einmal falsch!)
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The video I’m listening to in another tab had a soundtrack resembling those YT vids purporting to reveal all about some top secret (and often imaginary) project. He should rethink that.

http://cannae.com/about

Here’s Shawyer’s site:

http://www.emdrive.com/

and a paper of his:

http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf


62 posted on 08/02/2014 1:48:37 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/)
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To: FredZarguna

You said this in your first post:

“NOBODY thought Goddard’s ideas were kooky in the least.”

I wasn’t talking about physicists. I was talking about the general public, you know, readers of the New York Times, not The Physical Review.

In 1920 the NY Times lampooned Goddard’s ideas. They didn’t officially retract them until the moon landing in 1969. And that was 24 years after Goddard died.

See here:

http://www.popsci.com/military-aviation-amp-space/article/2009-07/new-york-times-nasa-youre-right-rockets-do-work-space


63 posted on 08/02/2014 3:16:17 PM PDT by chaosagent (Remember, no matter how you slice it, forbidden fruit still tastes the sweetest!)
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To: chaosagent
My original comment was about silly lay people, not engineers or hard-discipline scientists. Too many people on FR have taken anti-science positions [like, ironically, the New York Times.] It's unlikely that Goddard cared one bit about the popular press which has eternally, invariably been populated by innumerate morons and scientific illiterates.
64 posted on 08/02/2014 3:28:48 PM PDT by FredZarguna (Das ist nicht nur nicht richtig, es ist nicht einmal falsch!)
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To: InterceptPoint

“Someone needs to explain how you change the wavelength of a photon without some non-linear mechanism. Are we really talking about somehow filtering the AVERAGE wavelength of a broadband energy source as a function of the direction of travel in the cavity?”

They say it’s just the geometry of the conical resonating chamber thats force the microwaves to change wavelength, which then alters the group velocity of the waves in a relativistic effect.


65 posted on 08/04/2014 7:37:17 AM PDT by Boogieman
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To: sten

“...each wave would bounce towards the other emitter and get cancelled... but the bounce point would receive the energy.”

I don’t know if this would work. You would have to attune the waves so that they would cancel each other out through destructive interference. If you did that, I think they would cancel out at the reflection point, with no net effect.

You might be able to time it to work though. You would have to turn on only one emitter, then, after that emission hit the front wall, turn on the other emitter to cancel it after the bounce.


66 posted on 08/04/2014 8:17:48 AM PDT by Boogieman
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To: FredZarguna

Your knowledge is greater than mine. I am interested in learning higher mathematics and physics. Can you recommend some good resources? I had a brief flirtation with Lorentz transformations, but what I did know I have forgotten. Similarly, I am interested in studying more advanced physics than what I know now.

Interestingly, I developed a theory to allow anti-gravity devices, a way to actually build such a device. I took it to a graduate level physics lecture (they were discussing Eigenvectors). After the class I approached the professor and presented my theory. He was unable to punch any holes in it and after about 40 minutes he decided that I had “discovered” relativity but from a different approach. I want to know if my theory is correct or not, but I need more education to help in that endeavor.


67 posted on 08/06/2014 8:08:56 PM PDT by lafroste (matthewharbert.wix.com/matthew-harbert)
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