Propellantless thrust?

[Ser Scot A Ellison]

Here's an article from the Telegraph that seems to indicate confirmation that the "EM" Drive can produce thrust without propellant:

http://www.telegraph.co.uk/news/science/space/11769030/Impossible-rocket-drive-works-and-could-get-to-Moon-in-four-hours.html

From the article:
 

The drive is capable of producing thrust several thousand times greater than a standard photon rocket and could get to Mars within 70 days or Pluto within 18 months. A trip to Alpha Centauri, which would take tens of thousands of years to reach right now, could be reached in just 100 years.

"Our test campaign cannot confirm or refute the claims of the EM Drive but intends to independently assess possible side-effects in the measurements methods used so far," said Prof Tajmar in anew

"Nevertheless, we do observe thrust close to the actual predictions after eliminating many possible error sources that should warrant further investigation into the phenomena."

If this does prove true it is rather exciting. If nothing else because missions no longer need to bring along vast amounts of propellant to travel long distances. :)

[Yagathai]

It does not confirm anything. The experimental results are extremely dubious. No reputable scientist is calling it anything close to confirmed, and between you and me this is total bullshit vaporware.

[Ser Scot A Ellison]

Maybe. I hope not.

[Free Northman Reborn]

I have followed the progress on the EMdrive very closely on the NasaSpaceflight forum for the last year or so.

It is getting serious attention from some very learned people over there. Which is disappointing to me in that it drags attention away from the really exciting propellantless propulsion work that has been done on the Woodward Mach Effect by Prof. James Woodward and now continued by Prof. Heidi Fearn.

The problem with the Emdrive is that they have no plausible theory as to how it is generating the supposed thrust. Woodward in contrast has solid theory backing up his work which is consistent with Einstein and mathematically sound.

The EMdrive will most likely come to nothing, and 50 years from now we will regret the wasted years during which it diverted funding and research from the Woodward Effect, which will change the world as much as the steam engine did.

Edit

Just to add that the thread title is wrong. We are talking here of thrust without propellant, not thrust without propulsion, which wouldn't really make sense.

[Wise Fool]

Solar sails, laser propulsion, ion drives, there are a lot of propellant-less propulsions. Thing is, that doesn't really matter. This has been the case for as long as space travel has been around. Not having to carry around propellant is good, but it doesn't cheat the rocket equation. There's no getting around delta-v limitations. If propellant isn't the limitation, then power is, or thrust-to-weight, or time itself. There are always trade-offs and the problems facing space travel aren't really that we don't have the required miracle engine. Granted, something really miraculous, like a warp drive, now that would be a machine worthy of praise. But just something that isn't, strictly speaking, a rocket? Meh.

[ThinkerX]

I have been closely following the relevant threads at the NSF site for the past year. Lots of very bright people putting serious amounts of their own time and money into this. Yet the 'is it real' meter remains stuck at 'maybe.' There are quite a few tests with slightly differing setups showing thrust several thousand times that of a photon rocket...in an atmosphere. In a vacuum, there are now two sets of tests showing thrust on the order of a few dozen times that of a photon rocket.

There are *preliminary* MEEP models which show some downright fascinating and bizarre activity going on inside the device.

A convergence seems to be developing with the theory work, with some concepts not maligning Conservation of Energy or Conservation of Momentum.

More and more test devices are being built.

Yet severe artefacts - particularly thermal and thrust measurement remain. Allowing for those (and other assorted artefacts) the EM Drive remains 'interesting enough to warrant further research, but by no means validated.'

And for what little it might be worth at this point, very, very few folks involved in the NSF discussions are claiming an 18 month trip to Pluto anytime soon. Mostly, they are tackling various technical problems one slow step at a time.

[Altherion]

A convergence seems to be developing with the theory work, with some concepts not maligning Conservation of Energy or Conservation of Momentum.

How do you reconcile something like this with conservation of momentum?

[ThinkerX]

How do you reconcile something like this with conservation of momentum?

I leave that to greater minds than mine. I can say that the people putting forth these theories claim CoM is not violated, though others take issue with their approaches.

Hmm...

Tried a couple times to explain the current theories, didn't do so well. Hence, the Wiki

http://emdrive.wiki/Main_Page

Note that the wiki is a tool used for active research, theory and practical, by those on the NSF site. As such, it is updated frequently.

[Free Northman Reborn]

I leave that to greater minds than mine. I can say that the people putting forth these theories claim CoM is not violated, though others take issue with their approaches.

Hmm...

Tried a couple times to explain the current theories, didn't do so well. Hence, the Wiki

http://emdrive.wiki/Main_Page

Note that the wiki is a tool used for active research, theory and practical, by those on the NSF site. As such, it is updated frequently.

Hi ThinkerX.

I've followed the Emdrive discussion on NSF on a daily basis during the same period. I have come close to messaging you over here to ask whether you are the same ThinkerX from over there. Great to have that confirmed.

What has struck me is the subtle antipathy that guys like Rodal etc in that forum have towards the Mach effect while at the same time being willing to spend hundreds of hours trying to find a way to make the EMdrive theoretically plausible.

And yet after all this time, as late as yesterday Dr Tajmar in his latest presentation reiterated that the theory put forward for the EMdrive's operation doesn't make sense and that he doesn't have a clue how it supposedly works.

This while Woodward and Fearn have much more humbly, quietly and methodically developed a very sound theoretical basis for the Mach effect, to the point of proving it from first principles.

Rodal in particular seems to criticize the Mach effect mainly due to its low thrust signatures, but it seems to me that all of the supposedly higher thrust results for the Emdrive have been produced under highly suspect conditions - either not in a vacuum, or with magnetic shielding suspect or with thermal influences unclear etc.

And all of this while no one really knows how it supposedly works in the first place. Compared to this the Woodward Mach effect appears to be approached much more methodically and conservatively by its researchers, with magnetic, thermal, Dean drive effects etc already having been ruled out.

Note that Heidi Fearn presented the latest Woodward effect progress at the same confence as Tajmar's Emdrive presentation yesterday, but all of the media attention is once again fixed on the EMdrive. This despite the Emdrive on a theoretical basis being more akin to magic.

Can you give your thoughts on why there is so much more resistance to the Woodward effect, which in my view appears infinitely more elegant, experimentally tested and theoretically explained? For what it's worth, my view is that the guys doing the EMdrive work simply are much better at marketing themselves despite backing the wrong horse for all this time.

If the Mach effect could get the type of funding the Emdrive is getting we could well be on Europa or Titan much sooner than we we might have thought.

[Spring Bass]

I'm calling bullshit until it gets independent duplication and published in a peer-reviewed journal. If you're going to claim that you've found a loophole in the conservation of momentum, then you'd better have some strong evidence for it. 

[ThinkerX]

I'm calling bullshit until it gets independent duplication and published in a peer-reviewed journal. If you're going to claim that you've found a loophole in the conservation of momentum, then you'd better have some strong evidence for it.

That is *almost* the dominant attitude on the EM Drive threads at the NSF site. The principle movers possess a fair degree of skepticism, but not enough to dismiss the effect out of hand. At the moment, owing to issues with Tajmar's test, the needle is a bit closer to the 'false' end of the scale. But as many of Tajmar's issues are thought to stem from a flawed design, that could change.

I've followed the Emdrive discussion on NSF on a daily basis during the same period. I have come close to messaging you over here to ask whether you are the same ThinkerX from over there. Great to have that confirmed.

Are you a poster at NSF? Or strictly a lurker? ID?

I am ThinkerX on a number of sites dedicated to different topics.

What has struck me is the subtle antipathy that guys like Rodal etc in that forum have towards the Mach effect while at the same time being willing to spend hundreds of hours trying to find a way to make the EMdrive theoretically plausible.

My understanding is it was initially pressure from the site administrator that forced this disconnect. Woodward's device was considered to be a different animal altogether, yet it is very close in some ways to the EM Drive. Oh well, line had to be drawn somewhere.

[Free Northman Reborn]

That is *almost* the dominant attitude on the EM Drive threads at the NSF site. The principle movers possess a fair degree of skepticism, but not enough to dismiss the effect out of hand. At the moment, owing to issues with Tajmar's test, the needle is a bit closer to the 'false' end of the scale. But as many of Tajmar's issues are thought to stem from a flawed design, that could change.


Are you a poster at NSF? Or strictly a lurker? ID?

I am ThinkerX on a number of sites dedicated to different topics.


My understanding is it was initially pressure from the site administrator that forced this disconnect. Woodward's device was considered to be a different animal altogether, yet it is very close in some ways to the EM Drive. Oh well, line had to be drawn somewhere.

I'm strictly a lurker, but a daily one.

I find this topic fascinating. What I was wondering is why the Woodward effect thread on NSF doesn't receive similar levels of attention.

Also, I might then have seen you on Talk Polywell rather than NSF. I lurk there on a daily basis too.

[Mithras]

No need to get excited until someone discovers the secret of molecular transportation.

[Guest]

Scot - When I first saw this thread title I thought it was going to be a phrase coined by Stephenson in Seveneves. 

[Loge]

Conservation of momentum is a fundametal priciple and not just some pet theory physicists cling to for emotional reasons. You can't accelerate a spacecraft without accelerating something in the opposite direction. So what is the Woodward effect pushing against? No wonder nobody wants to research it. It's almost certainly bogus.

[Altherion]

Tried a couple times to explain the current theories, didn't do so well. Hence, the Wiki

http://emdrive.wiki/Main_Page

Note that the wiki is a tool used for active research, theory and practical, by those on the NSF site. As such, it is updated frequently.

Thanks. I browsed to the Frequently Asked Questions part of that wiki and they do have a link for Momentum Conservation, but sadly, all it says is "TBD".

 

Conservation of momentum is a fundametal priciple and not just some pet theory physicists cling to for emotional reasons. You can't accelerate a spacecraft without accelerating something in the opposite direction. So what is the Woodward effect pushing against? No wonder nobody wants to research it. It's almost certainly bogus.

It's not quite so bad as that. The claim is that it is pushing against distant matter in the universe via gravity or, if you prefer, recoiling against the gravitational field which then recoils against some very far away matter. The problem is that there is no evidence that gravity works that way.

[Free Northman Reborn]

Conservation of momentum is a fundametal priciple and not just some pet theory physicists cling to for emotional reasons. You can't accelerate a spacecraft without accelerating something in the opposite direction. So what is the Woodward effect pushing against? No wonder nobody wants to research it. It's almost certainly bogus.

Understand the theory before you criticize it.

It reacts against the rest of the matter in the universe. Much like a gravity assist maneuver steals a tiny bit of momentum from the planet it is sling shotting around, without expelling any propellant mass.

[Loge]

 

It's not quite so bad as that. The claim is that it is pushing against distant matter in the universe via gravity or, if you prefer, recoiling against the gravitational field which then recoils against some very far away matter. The problem is that there is no evidence that gravity works that way.

How do you reconcile that with causality? Ain't no such thing as instantaneus interaction over large distances. So is the effect generating gravity waves? Or does Woodward propose some kind of Aether?

[Free Northman Reborn]

How do you reconcile that with causality? Ain't no such thing as instantaneus interaction over large distances. So is the effect generating gravity waves? Or does Woodward propose some kind of Aether?

By way of Wheeler-Feynman absorber theory.

[Ser Scot A Ellison]

Loge,

How do you reconcile that with causality? Ain't no such thing as instantaneus interaction over large distances. So is the effect generating gravity waves? Or does Woodward propose some kind of Aether?

Not true. Quantum entanglement is instantaous interaction over long distances.