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General Discussion => New Physics for Space Technology => Topic started by: Chris Bergin on 04/29/2015 06:00 PM

Title: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/29/2015 06:00 PM
Over two months of work went into this article, involving the methodical and patient work of several people involved with the massive EM Drive thread - with the goal of creating an accurate and understandable (it's still high level science) article to reflect the interest in this development.

There have been several articles - all feeding off our forum thread on this - but this is something we feel will be more of a full news overview article.

Article:
http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/

Written by José Rodal, Ph.D, Jeremiah Mullikin and Noel Munson - subedited by Chris Gebhardt. Thanks also Don Domonoske and member RotoSequence for the work in the special area where we built this article. We would obviously like to thank Paul March at Eagleworks for his interesting interactions on the thread, and the numerous other high level folk who may not be too obvious behind their usernames (standard for a forum - if only you knew some of the people behind usernames on the SpaceX and such sections!)

Main EM Drive Thread (now over 500,000 views):
http://forum.nasaspaceflight.com/index.php?topic=36313.0

Attached are larger versions of the some of the images - the ones hard to read/see in our CMS style - (more, when found, can be added to the thread).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: rokan2003 on 04/29/2015 06:24 PM
Absolutely fantastic. Thanks so much Chris, and to the whole team here. You guys rock!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jcopella on 04/29/2015 06:35 PM
Thank you to the authors & editors of this article, and to the contributors on the EM thread for sharing your expertise. Well done, everyone.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: NovaSilisko on 04/29/2015 06:39 PM
Wonderful. I've said it a lot before, but it makes me really happy to see this being handled rationally, scientifically, and skeptically. Good work, everyone involved.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: kevinof on 04/29/2015 06:45 PM
Chris,
Spent the last hour reading this wonderful article  (sitting in Regents Park!) . Love the engineering and the physics and looking forward to seeing this technology used in the future.

Great work by you and the team as NSF.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Tuts36 on 04/29/2015 06:51 PM
Thank you so much for this article.  I've been aware of the EM Drive threadnought for awhile, and surmised that there was Something There from the sheer enthusiasm therein, but haven't had the time or the brains to make much sense out of it.  Now I at least understand what the excitement is about!



Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/29/2015 06:55 PM
Chris,
Spent the last hour reading this wonderful article  (sitting in Regents Park!) . Love the engineering and the physics and looking forward to seeing this technology used in the future.

Great work by you and the team as NSF.

Thanks for the above and the other comments, although I really don't deserve any credit. All the work was done by the guys accredited in the opening post.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: scienceguy on 04/29/2015 07:03 PM
Is the trip time to alpha centauri based on the space drive, or based on the power source?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rocket Science on 04/29/2015 07:14 PM
Epic article! :) I’m really looking forward to the tests...  8)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Raj2014 on 04/29/2015 07:15 PM
Thank you for the article Chris, excellent work. This is great news. I hope there will be more testing done and hopefully this technology will be out soon.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tchernik on 04/29/2015 07:16 PM
I've read the old and new Emdrive threads complete, and I'm still enthralled reading this article.

Congrats for doing a very good overview!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 04/29/2015 07:16 PM
Thanks for that article all those who contributed to it. Nice to see the essence of what is spread across a huge thread condensed down to an easily digestible chunk.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: corrodedNut on 04/29/2015 07:17 PM
To quote another thread: "Who are you guys?"

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 04/29/2015 07:19 PM
Fantastic work 8) .
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Tuts36 on 04/29/2015 07:20 PM
Epic article! :) I’m really looking forward to the tests...  8)

Same here!  Although they are going to have to relocate to Bozeman, Montana first.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: cuddihy on 04/29/2015 07:22 PM
Great article Dr. Rodal, Mulletron, Chris, and others! Gets to the heart of the excitement!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: teookie on 04/29/2015 07:23 PM
I've been binging on emDrive papers, theorys, and forum banter for the past few days.  This is truly exciting stuff.  We may be on the cusp of new physics and new possibilities.  Many thanks to those who are making all this possible, and thanks for taking time to share it all with us on the forums.

I would like to throw out one question on the subject.  The paper linked at the top of this thread, along with most of the forum discussions regarding possible emDrive applications have been focused on space travel.  But wouldn't it be possible to use emDrives terrestrially as well?  Think helicopters with no downdraft, levitating cars or trains.  Heck, why not a emDrive SSTO vehicle?  Are these concepts within the realm of possibility?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Cherokee43v6 on 04/29/2015 07:31 PM
Articles like this were the reason I first started lurking here and later started to participate in the forums.

Great read and really interesting.  I look forward to seeing more on this very Star Trek technology.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 04/29/2015 07:32 PM
Before we gets lots of questions about terrestrial applications.

Quote
18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

http://emdrive.com/faq.html
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 04/29/2015 07:35 PM
I've been binging on emDrive papers, theorys, and forum banter for the past few days.  This is truly exciting stuff.  We may be on the cusp of new physics and new possibilities.  Many thanks to those who are making all this possible, and thanks for taking time to share it all with us on the forums.

I would like to throw out one question on the subject.  The paper linked at the top of this thread, along with most of the forum discussions regarding possible emDrive applications have been focused on space travel.  But wouldn't it be possible to use emDrives terrestrially as well?  Think helicopters with no downdraft, levitating cars or trains.  Heck, why not a emDrive SSTO vehicle?  Are these concepts within the realm of possibility?

If there is a mechanism to interact with the fabric of spacetime itself in a manner as the EM-drive type devices seem to do, then I think the imparted impulse on the virtual 'plasma' should show up in some suprising form or another in the vicinity of such a drive. I could imagine this effect as a 'gravity-like' interaction (maybe 'pulling' in front of the drive, 'pushing' behind the drive) with the surroundings. But hey.. let's first try and demonstrate that the new simulation code-predicted relation between input energy and thrust is observable.. shall we?
;)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Tuts36 on 04/29/2015 07:39 PM
... But wouldn't it be possible to use emDrives terrestrially as well?  Think helicopters with no downdraft, levitating cars or trains.  Heck, why not a emDrive SSTO vehicle?  Are these concepts within the realm of possibility?

Firstly, congrats on your first post!  And to answer your question, it probably wouldn't be cost effective because of the amount of electricity you'd need to generate just to fight earth's gravity.  The amount of thrust per kilowatt is extremely small.  But for space, it'd be worth it not to have to use chemical propellants to move or make orbital corrections.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: alang on 04/29/2015 07:40 PM
I think that NasaSpaceflight.com's credibility will survive this. Anyway, I'm an empiricist - fly the thing and we'll see if it's a boondoggle.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: rds100 on 04/29/2015 07:43 PM
So when can this be tested in real world conditions, i.e. on a satellite? How large a satellite would be needed? Would a cubesat suffice?

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: teookie on 04/29/2015 07:57 PM
I think that NasaSpaceflight.com's credibility will survive this. Anyway, I'm an empiricist - fly the thing and we'll see if it's a boondoggle.

Heh, thats why this is so interesting.  We have empirical results form multiple experiments, but no concrete theory as to why/how it works yet.  Stay tuned!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 04/29/2015 08:05 PM
Congratulations to all involved in this project!

Tomorrow Mars, next week Alpha Centauri!

(Ok, I'm rushing it a bit, but still...)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: indigodarkwolf on 04/29/2015 08:12 PM
Like many folks (I'd hope), I was initially skeptical of the claims that a seemingly closed system could create a measurable thrust due to anything besides experimental error (much like certain claims of low-energy nuclear reactions that caught the attention of mainstream press a few years back). I'm surprised, and excited, that this still has merit.

I'm sure that I have many extremely novice-level questions, but I have two in particular that I'm curious about.

Is the crux of Dr. White's theory that electron/positron pairs from the quantum vacuum are being asymmetrically displaced by the microwave resonance before annihilating with each other to return to the quantum soup? I can roughly follow the analogy of a boat motor pushing against the medium around it, but wouldn't positrons and electrons (even virtual ones, if we're talking about quantum electrodynamics) have equal and opposite reactions to an electric field, resulting in zero net thrust? Is there some reason that the quantum vacuum, or virtual particles from it, would prefer a particular charge to result in thrust?

Possibly related, but I couldn't help but notice at the tail end of the article that the subject switched from discussing thrust of the EM drive design at Eagleworks to discussing the possibility of spacetime distortions due to EM fields varying with time. Are there any theories about why varying EM fields would expand or contract spacetime? Does this relate to where the thrust of the EM drive comes from, or is this just a sneaky little "we're actually wondering if we've accidentally discovered warp drive technology"?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Elmar Moelzer on 04/29/2015 08:34 PM
Excellent article! I have originally been very skeptical of the claims, but I have since become a bit more optimistic. Lets hope all of this will work out.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: clongton on 04/29/2015 08:35 PM
Epic article. I have been following the EM Drive threads sense they began but I must admit that the physics those guys are working thru are beyond my ability to comment intelligently. This article actually pulls a lot of what they were saying together in a way that I can almost understand it. Beyond that I really don’t have much more to say – I am too blown away. We appear to be at the threshold of an entirely new ear of space transportation and I can’t wait to see what becomes of this. In light of the potential payoff in terms of capability and national prestige I really hope the Congress will provide sufficient funding to continue this work at a reasonable pace.

I’ll be going back into lurking mode on the newest thread now, trying my hardest to work thru what those guys are saying. Thank you for doing the article. Very much.
 :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 04/29/2015 08:43 PM
Epic article Chris. I have been following the EM Drive threads sense they began but I must admit that the physics those guys are working thru are beyond my ability to comment intelligently. This article actually pulls a lot of what they were saying together in a way that I can almost understand it. Beyond that I really don’t have much more to say – I am too blown away. We appear to be at the threshold of an entirely new ear of space transportation and I can’t wait to see what becomes of this. In light of the potential payoff in terms of capability and national prestige I really hope the Congress will provide sufficient funding to continue this work at a reasonable pace.

I’ll be going back into lurking mode on the newest thread now, trying my hardest to work thru what those guys are saying. Thank you for doing the article. Very much.
 :)

I believe that eventually we have to start to think and act as a species, not as individuals or national states. If this technology is what it appears to be, then this knowledge has to be shared with everyone. Which is basically happening right now in those precious NSFF threads.
;D
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ThereIWas3 on 04/29/2015 08:57 PM
That last illustration, with the double ring "Enterprise", shows a bluish exhaust or ionization trail.  Maybe I misunderstood something, but I thought the EM drive did not have an exhaust.  Artistic license?  Pre-existing picture?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: aceshigh on 04/29/2015 09:03 PM
I just want to point out that the final draft of the 3D Warp Drive, following Dr Sonny White's theories, is quite different. Sonny worked together with the 3D modeller to ensure the spaceship model followed his theory parameters... well, not the entire spaceship of course, just the part about the rings width and how close to the rings the entire ship needs to be (I guess that long cockpit would stay out of the warp bubble)


this is the final image that was circulating all over the internet some months ago (only links because the images are big and destroyed page formating)
http://www.icarusinterstellar.org/wp-content/uploads/2014/06/14305613177_9ef4f4e69d_o.jpg
http://i.kinja-img.com/gawker-media/image/upload/s--jf_6nN4K--/huktzitxzojen9b5nvoi.jpg


here, a smaller image
(http://www.geometrycode.com/wp-content/uploads/2014/06/torusInWarpDrive.jpg)



most noticeable of course is the width of the rings... the thinner they are, the more negative mass would be needed according to Sonny White, until you need "Jupiter like negative masses", like in Alcubierre Drive.

compare how thin they are here
http://www.icarusinterstellar.org/wp-content/uploads/2012/10/2011sotl_rademaker_r01.jpg
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Baranquilla on 04/29/2015 09:04 PM
That article is amazing. Thanks for the effort guys!

When I finish my Geography Master and my Thesis next month, I will apply for the Master of space science at my Uni, this is what put me over the edge. Things like this make me want to be part of the Space Industry!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: UneducatedNitwit on 04/29/2015 09:33 PM
This is great work, guys.  I just finished reading through the threads this morning.  I'm much more impressed now with how thorough and scientific you have been than I was when I first stopped in to investigate this claim.

This article will be an important resource for any journalists who wish to make your story known.  No matter what the ultimate outcome of your work is, even if it is nulled next week, I am glad I spent the time reading what you all have written.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tchernik on 04/29/2015 10:02 PM
Epic article Chris. I have been following the EM Drive threads sense they began but I must admit that the physics those guys are working thru are beyond my ability to comment intelligently. This article actually pulls a lot of what they were saying together in a way that I can almost understand it. Beyond that I really don’t have much more to say – I am too blown away. We appear to be at the threshold of an entirely new ear of space transportation and I can’t wait to see what becomes of this. In light of the potential payoff in terms of capability and national prestige I really hope the Congress will provide sufficient funding to continue this work at a reasonable pace.

I’ll be going back into lurking mode on the newest thread now, trying my hardest to work thru what those guys are saying. Thank you for doing the article. Very much.
 :)

I believe that eventually we have to start to think and act as a species, not as individuals or national states. If this technology is what it appears to be, then this knowledge has to be shared with everyone. Which is basically happening right now in those precious NSFF threads.
;D

Indeed. If these findings are validated, then most countries, enterprises and wealthy citizens would have the recipe for at least a functional space drive.

Of course, you need a lot of work, effort and development to produce even the simplest functional one. But once any open source designs exist (and they would be produced shortly after the initial validation), it should be feasible, for practically anyone to build one (compared with the  relative exclusivity of the existing Space Age technologies, like rockets). Something like the ongoing Drone Age but for space access and ships...

That means the problem of space access and use becomes everyone's, literally and metaphorically.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RanulfC on 04/29/2015 10:02 PM
Thank you so much for this article.  I've been aware of the EM Drive threadnought for awhile, and surmised that there was Something There from the sheer enthusiasm therein, but haven't had the time or the brains to make much sense out of it.  Now I at least understand what the excitement is about!

"Threadnought"? Oh I am SO stealing that word!

Randy
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: punder on 04/29/2015 10:09 PM
Indeed. If these findings are validated, then most countries, enterprises and wealthy citizens would have the recipe for at least a functional space drive.

Like Elon Musk.  Hard to imagine that he isn't looking into this to see if it passes his own personal "smell test." 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TomH on 04/29/2015 10:14 PM
Absolutely astounding. Interesting question about whether this damages the quantum vacuum. The only tiny nit I had was that Ohio class SSBNs launch SLBMs, not ICBMs.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: indigodarkwolf on 04/29/2015 10:16 PM
Could someone explain the role of the HDPE dielectric insert that NASA used, and why a magnetron as the microwave source didn't require it?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JackFlash on 04/29/2015 10:21 PM
I'd be real surprised if Google, Inc. isn't all over this in pretty short order, given their stated intent to mine the asteroid belt.

Who knows, this could be the technical catalyst required to really kick that industry into high gear.

Cheers, MANY Thanks for all the science, and Congrats :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 04/29/2015 10:46 PM
I just want to point out that the final draft of the 3D Warp Drive, following Dr Sonny White's theories, is quite different. Sonny worked together with the 3D modeller to ensure the spaceship model followed his theory parameters... well, not the entire spaceship of course, just the part about the rings width and how close to the rings the entire ship needs to be (I guess that long cockpit would stay out of the warp bubble)


this is the final image that was circulating all over the internet some months ago (only links because the images are big and destroyed page formating)
http://www.icarusinterstellar.org/wp-content/uploads/2014/06/14305613177_9ef4f4e69d_o.jpg
http://i.kinja-img.com/gawker-media/image/upload/s--jf_6nN4K--/huktzitxzojen9b5nvoi.jpg


here, a smaller image
(http://www.geometrycode.com/wp-content/uploads/2014/06/torusInWarpDrive.jpg)



most noticeable of course is the width of the rings... the thinner they are, the more negative mass would be needed according to Sonny White, until you need "Jupiter like negative masses", like in Alcubierre Drive.

compare how thin they are here
http://www.icarusinterstellar.org/wp-content/uploads/2012/10/2011sotl_rademaker_r01.jpg

The reason why the picture shown in the article was chosen is because it is the picture that appears on a NASA report authored by Dr. White. 

The picture you posted in your post, instead, has "All Rights Reserved" by the artist, Mark Rademaker, a term of art used by artists and content creators to prevent ambiguity and clearly spell out the warning that their content cannot be copied freely.  It has not appeared (to my knowledge) in that form, in a NASA report.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 04/29/2015 10:59 PM
Thanks to the whole team behind this for a superb piece of science journalism. :)

This latest round of tests has radically narrowed the number of possible sources of experimental error. While it's possible the readings are an experimental artifact that view is getting harder and harder to support.

The fact that Dr White's team had developed a model that explains not just their  results but also why other teams have been much larger is very exciting, as it also offers some direct ways to increase the thrust. The use of magnetrons by other teams is an interesting example of how a less "controlled" experimental component (probably used due to cost and availability reasons) actually gave better results.

I hope the team will be able to leverage NASA's experience with magnetron systems as they were a key part of the JPL work on satellite solar power systems in the 70's and 80's.

This has gone a long way to vindicating SPR's original work in the early 2000's, although I suspect it's too early to consider the use of SPR's "2nd generation" concept of increasing the cavity conductivity by making it a superconductor. Likewise I'd wonder is HDPE the optimum choice for a cavity insulator, or just one that was available? If the latter that suggests the efficiency of small units could be improved by evaluating different insulators in the cavity

Some of the projected mission times enabled by this technology are just astounding.
 
A few words of caution should be mentioned. While there are space reactor designs for systems in the GW range they are thermal reactors, designed as heat sources to expel a fuel (normally H2).

The biggest electrical space reactors are much smaller units, with 10Kw(e) being known. A 100x fold scale up is not impossible but it will be demanding.

Note the fact that this is a fixed mass is the intriguing part. In principal any mission can return to Earth.  A possible candidate for the Kilowatt Reactor Using Stirling TechnologY (KRUSTY) programme perhaps?

There is one joker in the pack. It seems force produced falls as the payload accelerates, so this is an engine with a "top speed" limit.  It's not clear to me how high that limit is.

I think when a history of the first 50 years of NASA is written this programme may turn out to be one of NASA's most enduring in its effects (and one of its cheapest).  :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 04/29/2015 11:03 PM
Absolutely astounding. Interesting question about whether this damages the quantum vacuum. The only tiny nit I had was that Ohio class SSBNs launch SLBMs, not ICBMs.
Excellent point thank you  :) .   I'm always appreciative of such careful eyes.

It originated from a statement in one of the tread discussions and it should have been edited. (A lot of the editing effort went into making the article understandable and double checking the numbers, and we missed that acronym). 

I bet there are other errors still remaining to be found.  ;)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/29/2015 11:08 PM
Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

Just passed 30,000 reads. About 10 percent follow through into the EM Drive threads, which is standard for an article (bar the launch/event articles, as more go through for live coverage on the forum). Main EM thread now at 512,000 views, but it's organically rising in tandem with the article boost.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: EMPaul on 04/29/2015 11:23 PM
That was an astronishing read. Of course, this is early days, but the key to this is it's a path. It actually doesn't matter if it becomes a dead end, it very, VERY likely produces branches to take a new direction in, eventually resulting in something takes us further down the line and eventually to a breakthrough.

That is why it makes me excited, because it's pushing out of the box, which is the only way we'll find breakthroughs.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Jose Martinez on 04/29/2015 11:27 PM
Technical, very techical, but that's the tradition of this site, not to patronize the reader with sensationalism or dumbing things down, so while this is out of NSF's comfort zone on the subject, I think it was an excellent decision to press ahead with an article and the quality and objectivity is superb.

Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

I know you didn't write it, and I know you're a chemical propulsion hugger (Shuttle, etc. ;) ) but where would you stand in the above "color me...." scale?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 04/29/2015 11:36 PM
... But wouldn't it be possible to use emDrives terrestrially as well?  Think helicopters with no downdraft, levitating cars or trains.  Heck, why not a emDrive SSTO vehicle?  Are these concepts within the realm of possibility?

Firstly, congrats on your first post!  And to answer your question, it probably wouldn't be cost effective because of the amount of electricity you'd need to generate just to fight earth's gravity.  The amount of thrust per kilowatt is extremely small.  But for space, it'd be worth it not to have to use chemical propellants to move or make orbital corrections.

Even the claimed 1 N/kW experimentally measured thrust is NOT small. It's roughly what you'd get out of a 100% efficient rocket engine with 200 seconds of specific impulse.

If they start talking about 10 N/kW or more, you could trivially build a perpetual motion machine for commercial power generation by putting drives like this one on a centrifuge with a ~200 m/s tangential velocity and a dynamo at the center (power out is force times velocity, which at a certain speed becomes higher than the input power if the engine thrust is independent of velocity). At that point, the nuclear reactor talked about in the article is completely unnecessary.

This is one of many reasons why claims like these are something you should be VERY sceptical of. The entire thing smells of unicorns and wish fulfillment.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: punder on 04/29/2015 11:38 PM
Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

Just passed 30,000 reads. About 10 percent follow through into the EM Drive threads, which is standard for an article (bar the launch/event articles, as more go through for live coverage on the forum). Main EM thread now at 512,000 views, but it's organically rising in tandem with the article boost.

Wouldn't you feel weird if this stuff does work out, and your website was instrumental in creating an "interest phase change" that finally led to adequate financing for these efforts?  And someday people are flying all over the Solar System, and you're thinking "wow... I helped do this."  Wouldn't that be weird?   :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KelvinZero on 04/29/2015 11:40 PM
With propellentless propulsion and with FTL respectively, the most important thing I want to see in an article is a discussion of what it means wrt to free energy and time paradoxes respectively.

This isn't a knee-jerk "It is impossible because..", it is just that these
* are the most important questions,
* can usually be discussed with very simple mathematics,
..and without which it is not even clear what is being claimed, let alone whether a test satisfies that claim.

The physics that can actually implement the claim is probably beyond the scope of any mere rocket scientist let alone myself so of course I must defer judgement there.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/29/2015 11:50 PM

I know you didn't write it, and I know you're a chemical propulsion hugger (Shuttle, etc. ;) ) but where would you stand in the above "color me...." scale?

Chemical propulsion hugger! True I suppose! ;D

I'd probably be in the middle of that scale. I mainly know engineers, but one of my friends is a pretty high level scientist at the University of York and his motto is to be skeptical about everything. I'm not really of that nature, but I get what he means.

Remember, we had EM Drive being discussed on here for a LONG time. I even shut down the first thread as it seemed wild, but it was also becoming loose for the subject matter of this site. The second thread (the big one) was a solution to get it specific to space flight and to focus people on building a thread as a resource of updates and discussions. That clearly worked, but I was still too busy running around in my comfort zone of SLS and SpaceX threads, etc to notice how that thread was building.

Then a few things happened, from a few notes from NASA friends I trust, to noticing how it was getting some interesting attention, so I followed it for a while - albeit not really understanding it - and then realized it was actually a very good thread per who was posting in there and how it was progressing.

So we made the jump to reflect the interest in the thread and see if we could perhaps write it up into a summary article, partly because of the interest, partly because of it being something fresh per what we normally publish (launch, dock, launch, land, launch, SLS, We love Elon, launch and so on) and partly because the best thing about this site is its community - which I'm both trying to tap into and provide a conduit to those who want to do more than just post on the forum.

The latter point is the interesting element for me, because I said I'd read the entire thread and try and get a grip on the subject, but I soon realized I clearly wasn't educated enough to process it, but I've always said over 50 percent of the readers here are more versed in the subject matter (all subjects) than I can ever dream to be - I just started a site for STS-114 and it just happened to take off, so I'm just a lucky guy.

Asking for people to help build an article was the only way this would work and we got Dr. Rodal and others - and we had a bit of fun trying to merge the challenge of their education with my goal of converting their knowledge (and that of the thread) into a news article. A bit like a square peg into a round hole, but we got there! ;D

Do I understand it all now? Nope, but I've got the basic idea behind what is being worked on here, thanks to that resulting article - and if that's progressed my own understanding, then that's the litmus test for our readership being able to read it - the "If Chris can read it, then we've done an OK job to translate it to Joe Public!" test and having my assistant editor, Chris Gebhardt, shake it more into a news article really helped too - as he's a super writer.

I'm digressing, but are we making any claims here? No. We're covering a subject that was already very interesting to a lot of readers here, and this site serves its readership. We've been fortunate enough to have some excellent help to ensure this article was the best we could hope to produce on this subject, so that's a job done in my eyes.

Back to launch, dock, launch for me tomorrow, but I have no doubt this subject will continue to run and IF there's progress, we now have a baseline article as a foundation for follow ups.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: arachnitect on 04/29/2015 11:55 PM
Skeptical does not even begin to describe how I feel about this.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/30/2015 12:09 AM

Wouldn't you feel weird if this stuff does work out, and your website was instrumental in creating an "interest phase change" that finally led to adequate financing for these efforts?  And someday people are flying all over the Solar System, and you're thinking "wow... I helped do this."  Wouldn't that be weird?   :)

That'd be cool, but I doubt we have that sort of influence.

Our best achievements are (we're up to nine that I know of over the years - and yes I'm keeping count) people who have turned up on the forum and have got a job in aerospace by talking to/getting noticed by people here who are already in aerospace, who went on to get them through the door.

I don't think we can beat that, but quiet frankly knowing the site helped facilitate the above keeps me sane when it gets a bit crazy here.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: a_langwich on 04/30/2015 12:18 AM
Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

Just passed 30,000 reads. About 10 percent follow through into the EM Drive threads, which is standard for an article (bar the launch/event articles, as more go through for live coverage on the forum). Main EM thread now at 512,000 views, but it's organically rising in tandem with the article boost.

Twitter is tough on some things, not so tough on others. 

I'm very skeptical still.  One smell test which it continually fails:  when people spend far more time talking about what it will mean if it's true, rather than focusing on whether it is true...bad smell.  Especially on a topic that at the most optimistic telling requires accepting extensive revision of many scientific principles, and accepting what its proponents acknowledge are a whole raft of theories that do not have mainstream acceptance.  Makes for great fiction, but very poor science, because it puts the spotlight front and center on what is to the researcher a conflict of interest, a source of impartiality which threatens the integrity of their work.  Queue up the Feynman quote about not fooling yourself.

It would not be the first bit of skanky science which NASA, or NASA researchers, have embraced.  (Arsenic-based life forms, anyone?)

I'll look forward to seeing results several orders of magnitude larger by the NASA team in a controlled environment.  And to see what the physics academic community thinks about the various theories put forward by the teams.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TomH on 04/30/2015 01:08 AM
Skepticism is what separates science from superstition. The branch of philosophy known as Epistemology deals with How do you know that what you claim to be true really is true? Historically, these are the main ways that people have claimed to know truth.

-A deity told me.

-It's written in an infallible book.

-It was stated by a holy man who is incapable of error.

-Conventional wisdom-acceptance by many

-Basic Aristototelian observation

-Logic: induction, deduction, syllogism, dialectic, rationalism, empiricism, idealism, constructivism, etc., each in isolation.

-Scientific methodology: integrated use of observation, induction, deduction, hypothesis, testing, conclusion, peer review, multiple independent concurrence. In some instances, placebo controlled double-blind trials.

The last of those, the hypothetic-deductive model of scientific investigation is the only one which actively tests and proves or disproves a hypothesis.

So far, I see nothing questionable in the research done to date, however jumping to conclusions is premature. Remember cold fusion?

To some, it may seem counterintuitive that you can push on nothing. On a highway, torque pushes on the pavement. In a vacuum, we have thus far had to depend on Newton who gives us equal and opposite reactions as the propellant burns or SEP or NEP propels gasses in the opposite direction. But what many conceive of as a complete vacuum actually isn't. That void does contain the fabric of spacetime, something we know can be warped by gravitational and EM fields. It has appeared that the only resistance to acceleration through spacetime relates to Einstein's theories: an object approaching c infinitely gains mass and cannot reach c. But what if it is possible actually to push against the fabric of spacetime? I am no quantum nor cosmological physicist, but what the article says about electron-positrons is intriguing. It sounds like the EM field is not pushing against NOthing, but SOMEthing that actually exists within what we typically consider to be the empty vacuum of space. Einstein's theories seemed very counterintuitive to the Newtonian physicists at first consideration. We are constantly learning more about quantum and cosmological physics. We've only just recently confirmed the existence of the Higg's Bosun; all other sub-atomic particles actually have no mass in isolation, but do have mass due to the extension of the Higg's Field around them. There is a great deal to investigate. MUCH more research has to be done. And yes, skepticism is one of the main driving components of science. After all the rigor has been applied, lets hope this turns out to be like Einstein's theories and not like cold fusion.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rocket Science on 04/30/2015 01:12 AM
When you have eliminated the impossible, whatever remains, however improbable, must be the truth...
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JackFlash on 04/30/2015 01:17 AM
@a_langwich: I rather think you're falling victim to the same sort of emotionally-charged evaluation you're assigning to others, only in reverse.

I don't work in the field, I'm a computer/network guy by trade, artist and dreamer by predisposition (yup), but I have to say, your insinuation that the greater volume in this discussion is of the 'what it will mean if it's true' sort is something I just can't get my head around.

The thread that is the source material for this article is so science and data dense it boggles the mind. More, your assertion that the theory building 'requires accepting extensive revision of many scientific principles, and accepting what its proponents acknowledge are a whole raft of theories that do not have mainstream acceptance' seems a little off base too, as the theory I've been able to find on the underlying subjects are quite old, some quite central to quantum mechanics ('Heisenberg's uncertainty principle' comes to mind). And seriously, how is the science presented by these researches in any way informed or impacted by what NASA has paid other people to do? Why the strawman?

Seriously, a bit of self-examination may be in order here. Just sayin'.

Follow the data, not your heart.

EDIT: Address individual in question, per suggestion of TomH (thanks)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 04/30/2015 01:18 AM
Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

Just passed 30,000 reads. About 10 percent follow through into the EM Drive threads, which is standard for an article (bar the launch/event articles, as more go through for live coverage on the forum). Main EM thread now at 512,000 views, but it's organically rising in tandem with the article boost.

Twitter is tough on some things, not so tough on others. 

I'm very skeptical still.  One smell test which it continually fails:  when people spend far more time talking about what it will mean if it's true, rather than focusing on whether it is true...bad smell.  Especially on a topic that at the most optimistic telling requires accepting extensive revision of many scientific principles, and accepting what its proponents acknowledge are a whole raft of theories that do not have mainstream acceptance.  Makes for great fiction, but very poor science, because it puts the spotlight front and center on what is to the researcher a conflict of interest, a source of impartiality which threatens the integrity of their work.  Queue up the Feynman quote about not fooling yourself.

It would not be the first bit of skanky science which NASA, or NASA researchers, have embraced.  (Arsenic-based life forms, anyone?)

I'll look forward to seeing results several orders of magnitude larger by the NASA team in a controlled environment.  And to see what the physics academic community thinks about the various theories put forward by the teams.

Further discussing in the article why Dr. White's theories do not have mainstream acceptance (beyond stating that the Quantum Vacuum is supposed to be immutable and not degradable, and it is supposed to be the zero-point energy, etc.) proved too difficult to do in an article aimed at a wider audience.  For example, Dr. White is invoking 5-dimensional branes from string theory and other conjectures like capability of the vacuum to support particle-vacuum or particle-particle interactions that allow lower energy, ground states (see http://hdl.handle.net/2060/20150006842 and   http://en.wikipedia.org/wiki/Brane_cosmology ) to justify this.  Properly discussing this for a wider audience proved impossible.

Another alternative was to discuss the experimental measurements as an artifact.  Here is an exact solution of the thermal buckling problem for the EM Drive's truncated cone base that I wrote that looks plausible

https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT

Although this will also explain the measurements in a vacuum, it suffers from the fact that buckling is very dependent on initial imperfections and therefore it does not explain why the thrust would consistently point in one direction.

@aero has contributed a 2-D MEEP (MIT's Finite-difference time-domain analysis of electromagnetic systems) of evanescent waves leaking from the EM Drive, and possibly interacting with the stainless steeel vacuum chamber.

However, Paul March conducted an experiment at NASA Eagleworks with the EM Drive completely outside the stainless steel chamber that appears to have nullified that explanation.

Analyses of other alternative explanations for the experiments as artifacts (and why they are inconclusive) proved to be too difficult to do in the text of the article.

I fully agree that skepticism is of paramount importance in science. Paul March (of NASA Eagleworks) has contributed detailed information about the experimental set-up, and if anybody is interested, they are very welcome to contribute in the EM Drive thread any engineering, preferably quantitative, theoretical, numerical or experimental analysis they may be able to contribute to try to show these experiments as experimental artifacts.

It is also true that (quoting here  ;) )  “Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire universe, and all there ever will be to know and understand.”
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TomH on 04/30/2015 01:20 AM
I rather think you're falling victim to the same sort of emotionally-charged evaluation you're assigning to others, only in reverse.

I don't work in the field, I'm a computer/network guy by trade, artist and dreamer by predisposition (yup), but I have to say, your insinuation that the greater volume in this discussion is of the 'what it will mean if it's true' sort is something I just can't get my head around.

The thread that is the source material for this article is so science and data dense it boggles the mind. More, your assertion that the theory building 'requires accepting extensive revision of many scientific principles, and accepting what its proponents acknowledge are a whole raft of theories that do not have mainstream acceptance' seems a little off base too, as the theory I've been able to find on the underlying subjects are quite old, some quite central to quantum mechanics ('Heisenberg's uncertainty principle' comes to mind). And seriously, how is the science presented by these researches in any way informed or impacted by what NASA has paid other people to do? Why the strawman?

Seriously, a bit of self-examination may be in order here. Just sayin'.

Follow the data, not your heart.

Whom are you addressing?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: watermod on 04/30/2015 01:21 AM
If Lockheed can get it's little Skunkworks Fusion Reactor working - these two technologies would be ideal mates.
 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: robertross on 04/30/2015 01:23 AM
Wow, what an inspiring article! Rarely do we get to see that side of spaceflight on the news site.
Great job to the team putting that one together.

I'm mainly into the physics side of things (despite not having a great grasp on the many nuances of the theoretical side of things) and have so many thoughts to throw out, but I'll save that for later.

I never even realized this was going on! I need to browse more of these other threads!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: indigodarkwolf on 04/30/2015 01:23 AM
Quote
It sounds like the EM field is not pushing against NOthing, but SOMEthing that actually exists within what we typically consider to be the empty vacuum of space.
My modern physics classes were a long time ago, but if memory serves, the idea is that particles are constantly popping in an out of existence in pairs - a particle and an anti-particle. They collide soon after. Their lifetime, and thus the the distance over which they can act, is bounded by uncertainty. They can even exchange wave packets with each other and with non-virtual particles, imparting force. "Something something something, Quantum Electrodynamics."

I probably just made a bunch of physics majors punch their monitors with how badly I butchered all that. I'm tired and trying to read all the math in Wikipedia's articles is making my head spin. I still have my notes from class somewhere, but I'll probably never dig them back up without being prompted to do so. Maybe someone could comment, whose education is a little less rusty than mine.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JackFlash on 04/30/2015 01:27 AM
@TomH:

This guy: a_langwich
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TomH on 04/30/2015 01:41 AM
@TomH:

This guy: a_langwich

I would recommend you edit the post to reflect that. You can quote part of what he said (just as I did here to you), or simply interpolate @a_langwich at the top.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: mheney on 04/30/2015 01:47 AM
I find myself skepitcial as well - but that's based on the old adage

“When you hear hoofbeats, think of horses, not zebras”

My suspicion is that, when all is said and done, this will turn out to be a horse, with a
mundane physical explanation that doesn't equate to a propellentless drive.  Because there
are an awful lot of plain old horses out there.

But - zebras exist.  And the best way to find a zebra is to look for one.

I AM impressed by the nature of the work being done in the investigation.  It's science at
its best.  Extraodinary claims require extraordinary proof - and the team is working on providing it.

So yeah, I'm expecting a horse.
But a zebra would be really cool ...
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Norm Hartnett on 04/30/2015 01:49 AM
“Eppur si muove“

While it is interesting to theorize on how and why EM may work and even more interesting to speculate on what the ramifications and applications of EM may be I would suggest that it is far more important to adequately fund experimental research to prove or disprove that it works at all. I know that there are many unfunded and underfunded questions in fundamental and theoretical physics that many feel are more important than EM but it would seem to me that clear focus on experimental tests for EM can be done at a fraction of the cost of most others. NASA and other national space agencies are the most likely to benefit immediately from such research and are the logical agencies to fund such research. All the arguments I have seen against EM rest on the lack of theoretical foundations, but eppur si muove!

I remain a hopeful skeptic. Hopefully further funding will become available as public interest grows.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: R.W. Keyes on 04/30/2015 03:03 AM
Thank you for writing this article. It nicely distills much of the information that has been posted here on the forums into a comprehensive and easy-to-read article. I've posted a link on Facebook, in hopes that my skeptical friends will be a bit more open to the idea of the EM-drive and the possibility of warp drive.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 04/30/2015 03:05 AM
“Eppur si muove“

While it is interesting to theorize on how and why EM may work and even more interesting to speculate on what the ramifications and applications of EM may be I would suggest that it is far more important to adequately fund experimental research to prove or disprove that it works at all. I know that there are many unfunded and underfunded questions in fundamental and theoretical physics that many feel are more important than EM but it would seem to me that clear focus on experimental tests for EM can be done at a fraction of the cost of most others. NASA and other national space agencies are the most likely to benefit immediately from such research and are the logical agencies to fund such research. All the arguments I have seen against EM rest on the lack of theoretical foundations, but eppur si muove!

I remain a hopeful skeptic. Hopefully further funding will become available as public interest grows.

Yes, adequate funding has been a huge issue to properly validate, or to nullify, the EM Drive.

For example, NASA's EM Drive truncated cone was made by Paul March (an engineer at NASA Eagleworks) himself in "his wife's dining room".

http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327937#msg1327937

(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=635221;image)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: kdhilliard on 04/30/2015 03:59 AM
Before we gets lots of questions about terrestrial applications.

Quote
18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

http://emdrive.com/faq.html

I assume that everyone here understands how important that quote is to their claim.  From the article, Yang is reporting a thrust over power efficiently of nearly  T/P = 1 N / kW, but March is projecting 500 to 1000 Newton/kW in 50 years time, though White's crewed missions to Mars is based on only 0.4 Newton/kW.

If constant efficiency were allowed, then with kinetic energy KE = 1/2 m v^2, dKE/dt = m v a = F v, so by the time a speed of v = P / F is reached, the kinetic energy would building at a greater rate than power is applied to the drive, so if you could do such a thing on Earth you could harness an engine to generate more power than it consumes, producing clean, cheap, unlimited power.  For Yang T/P = 1 N / kW, this break-even velocity is 1 km/s and for White's Mars ship it is 2.5 km/s, but for March's projected 500 to 1000 Newton/kW it is only 1 to 2 m/s.

Quote
6.
Q. Is the EmDrive a form of perpetual motion machine?
A. The EmDrive obeys the law of conservation of energy and is therefore not a perpetual motion machine. Energy must be expended to accelerate the EmDrive (see Equation 16 of the theory paper). Once the EmDrive is switched off, Newton’s laws ensure that motion is constant unless it is acted upon by another force.

http://emdrive.com/faq.html

What I don't understand, and what I didn't find in the faq, is how the drive remembers what reference frame it is suppose to be measuring its velocity against.  If the engine ran for a while to achieve a certain velocity and then shut down and coasted for a while, when it restarted, it must somehow still be tied to its initial reference frame so that it knows it already has some velocity which reduces its efficiency.  Do they offer any method by which that could happen?

~Kirk

Edit: Wording for clarity.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: luinil on 04/30/2015 04:16 AM
Yes, the speed reduces efficiency, there are only two ways for this to work :
- The drive remembers it's original reference frame to know it's speed
- There is an absolute reference frame for the universe the drive can accelerate/decelerate against (this contradicts relativity)

If someone has an explanation on this point I'd be happy to read it.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Ludus on 04/30/2015 04:38 AM
Excellent article. A lot of work went into distilling that huge thread.

A small spacecraft could provide unambiguous proof that the effect is real (if it's real). An EM drive satellite powered by PV could behave in ways that are impossible under conventional physics. It still wouldn't be clear what is happening but it would be undeniable that it's very important and worth a lot of funding.

What's the cheapest EM spacecraft design that should do clearly impossible things?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: QuantumG on 04/30/2015 04:49 AM
What's the cheapest EM spacecraft design that should do clearly impossible things?

About $10,000. You could Kickstarter it and get it on the next Dragon flight, ala A3R (http://en.wikipedia.org/wiki/Planetary_Resources#Arkyd_3_Flight_test_system). Heck, there's cubesats that have flown for less.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: aceshigh on 04/30/2015 07:10 AM
The reason why the picture shown in the article was chosen is because it is the picture that appears on a NASA report authored by Dr. White. 

The picture you posted in your post, instead, has "All Rights Reserved" by the artist, Mark Rademaker, a term of art used by artists and content creators to prevent ambiguity and clearly spell out the warning that their content cannot be copied freely.  It has not appeared (to my knowledge) in that form, in a NASA report.

thanks Dr Rodal.

It´s important to note that the warp-ship picture used in the NASA report authored by Dr White is also authored by Mark Rademaker and also has "all rights reserved" in his FlickR album
https://www.flickr.com/photos/yard2380/14469380046/in/set-72157644917560879

more than that, that warp-ship was only done in 3D by Mark Rademaker. The original design actually belongs to Matt Jefferies, the original designer of the Enterprise.
This ship used in the article is the XCV-330  Ringship, designed by Jefferies in the 60s AS a concept for the Star Trek TV show. (as we all know, this was not the ship concept favored by the producers)


Considering that BOTH ships images (XCV-330 Ringship and IXS Enterprise) have all rights reserved to Mark Rademaker, wouldn´t be better to contact him asking for permission and use the NEW design commissioned by Dr. Sonny White?

from Mark Rademaker's blog
"When I got invited by Dr. Harold "Sonny" White and Mike Okuda, I was absolutely stunned. Did that just really happen? A person from NASA contacted me to do artwork for them? Yes it did! After seeing my rendition of Matt Jefferies "Ring Ship", Dr. White thought that this would be a good starting point for a near future "Ring Ship". At least from a STEM perspective. Because that is the main goal: to get a warpship concept out there that would inspire young people to choose a career in STEM."

I find it weird that Dr White did not use the new drawings, since THOSE were the ones he advised Mark Rademaker and in fact, as Rademaker himself says, Dr White personally contacted him to ask him to make it.

The previous ship is Rademaker's "Ringship" and is not based in any real Warp drive Concept by Dr White. Rademaker did it from his own imagination, Dr. White liked it and used on a NASA paper, then later decided to contact Rademaker and suggest modifications so the ship would resemble "real warp drive theory by Dr White".




ps: Mark Rademaker recently "converted" his Warp Ship to a Q-Thruster (EM Drive) ship
his tweet
"Streaming the conversion of warp-ship to Q-thruster ship. Artist impression/ optimistic concept ;) http://www.twitch.tv/yard2380"


and here a link to Rademaker's FLICKR, where there are more images as well as diagrams of the ship
https://www.flickr.com/photos/123021064@N05/sets/72157644113972600/

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: aceshigh on 04/30/2015 07:14 AM
btw, not sure if the new Warp Ship image appears on any NASA paper, but on this video of Dr Sonny White, he shows the old Ringship design from Star Trek AND the new warp drive ship images based on his theories

starting at 26:40
https://www.youtube.com/watch?v=Wokn7crjBbA

screenshot from the video above, showing that Dr White has used the image on his presentations and probably some powerpoints.
http://i.imgur.com/P9vlaVY.jpg

so, considering that

1 - Dr White has used both ship images on his presentations/powerpoints

2 - both images are from the same author (Mark Rademaker) and are exclusive rights

3 - the ship image used in the article is actually based on a 60s concept art for Star Trek TV show

4 - the ship image used in the article does NOT follow the parameters established by Dr White for a warpship, while the newer images do follow those parameters, because they were commissioned by Dr White himself

I guess the image in the article should be changed.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: lele on 04/30/2015 09:11 AM
http://emdrive.com/ is maintained by Roger Shawyer (or by someone in his company, SPR Ltd.), I think the predictions written in this website should be taken with a grain of salt since there's no consensus on any theory which could explain the experimental results (whether or not they're an artefact).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WBY1984 on 04/30/2015 09:13 AM
I have limited understanding of this, but I'm still very skeptical (but hopeful!). The NASA experiments show exceedingly small thrust measurements, to the point where experimental error seems only too likely. The UK and Chinese experiments on the other hand, were comparative high power experiments in the open air that could have caused all kinds of convective effects.

There's all this talk of Mars missions, and we are nowhere even CLOSE to figuring out that this thing even works!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 04/30/2015 09:56 AM
I find myself skepitcial as well - but that's based on the old adage

“When you hear hoofbeats, think of horses, not zebras”
In Europe, yes.

In the US, yes.

On the Serengeti plain, no.

IOW context is important.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 04/30/2015 10:40 AM

can anyone explain this point better?

from http://emdrive.com/faq.html
Q. Why does the thrust decrease as the spacecraft velocity along the thrust vector increases?
A. As the spacecraft accelerates along the thrust vector, energy is lost by the engine and gained as additional kinetic energy by the spacecraft. This energy can be defined as the thrust multiplied by the distance through which the thrust acts. For a given acceleration period, the higher the mean velocity, the longer the distance travelled, hence the higher the energy lost by the engine.
This loss of stored energy from the resonant cavity leads to a reduction in Q and hence a reduction of thrust.

The key question is why can't you just turn the machine off and start again from a new reference frame, giving you a traditional interpretation of a propellentless drive and free energy.

Reading that Q/A, ascribing a 'book-keeping' ability to such a device in regards to reference frames sounds unphysical to me. I can't do anything with that. I tend to believe that Mr. Shawyer might have accidentally found something mind-blowing.. but his explanations just don't add up. It might work for, uh, different reasons than he assumes.
;)

Well you might ask how the electrons in the double slit experiment know they are being observed and therefore act differently.

Hmm.. I think that using the verb 'to know' in this context bears risk of mixing up human cognitive behavior and physical behavior of particles, that's actually also defined by the 'stuff' that's around it. When talking about EM-drives and Q-thrusters, I think it's correct to start thinking in terms of spacetime-engineering. Just as a double-slit experiment engineers spacetime by producing a local configuration of matter and a specific topology, what we might call Q-thrusters or EM-drives could be equally said to engineer spacetime by producing a local configuration of matter, time-varying energy and topology that possibly induces a hitherto unobserved behavior of QV.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KelvinZero on 04/30/2015 10:55 AM
It is notoriously difficult to understand what Quantum Mechanics means, but it tells you what is going to happen.

In this case I don't know what is claimed to happen if you turn the machine off and turn it back on later. There is a tree of obvious questions that would be best answered by a proponent who understands the maths.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Oli on 04/30/2015 11:55 AM

So this company SPR Ltd. has been working 15 years on this and the feasability of the concept is still not proven?

Well at least NASA is on it now, but I'm not optimistic.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tea monster on 04/30/2015 12:02 PM
What is the image of the bus-sized spacecraft pictured in the feature article? Who came up with that? It looks like a discarded blueprint from the modelshop of Zombies of the Stratosphere!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/30/2015 12:40 PM
What is the image of the bus-sized spacecraft pictured in the feature article? Who came up with that? It looks like a discarded blueprint from the modelshop of Zombies of the Stratosphere!

Page 21 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Norm38 on 04/30/2015 12:53 PM
Yes, the speed reduces efficiency, there are only two ways for this to work :
- The drive remembers it's original reference frame to know it's speed
- There is an absolute reference frame for the universe the drive can accelerate/decelerate against (this contradicts relativity)

If someone has an explanation on this point I'd be happy to read it.

I've seen acceleration and velocity used interchangeably.  Which is it?
Acceleration is absolute, a body is either at rest or accelerating and it takes a force to accelerate.  It at least makes some sense that force would fall off with acceleration (thrust is no longer asymmetrical?).

But for velocity?  Velocity with respect to what?  What is the frame of reference for these lab experiments conducted on the surface of a spinning rock hurtling around the sun that is also moving?

If the EM drive really is pushing against some quantum foam "ether", then an EM drive car should be able to go faster driving West than East, because going West it would be slowing down relative to absolute space-time and therefore gain acceleration.

Has anyone thought to do the experiment at two different points in Earth's orbit, when our absolute velocity vector is pointing in two different directions?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sghill on 04/30/2015 01:02 PM
CNet has a loving little article (albeit a bit hyped IMHO) regarding the NSF article and associated thread this morning.  They even reached out to Paul March (poor guy, I hope we didn't ruin his day) for a quote.

http://www.cnet.com/news/nasa-tests-physics-defying-method-of-space-travel-em-drive/
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 04/30/2015 01:04 PM

So this company SPR Ltd. has been working 15 years on this and the feasability of the concept is still not proven?

Well at least NASA is on it now, but I'm not optimistic.

Working for fifteen years on VERY limited funds, and having to use unpaid interns for much of the work.  (No knock against interns, just pointing out the shoestring nature of this project).

     That they've accomplished as much as they have to this point is remarkable.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Lampyridae on 04/30/2015 01:06 PM
I think velocity simply refers to the delta. The (theoretical) ability of the EM thruster to hover at high efficiency could be considered analogous to running a kerosene burner to fill a hot air balloon, as opposed to using the heat energy to drive a jet engine.

Oh and somebody get Paul March, Dr. Rodal and the rest a Bell's. It may yet be nothing but it would be a damn impressive nothing.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Jester on 04/30/2015 01:07 PM
Great work and article, found this:

Dr. Harold "Sonny" White performs an experiment using the White-Juday Warp Field Interferometer in the Eagleworks Laboratory
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Celebrimbor on 04/30/2015 01:09 PM
Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

Just passed 30,000 reads. About 10 percent follow through into the EM Drive threads, which is standard for an article (bar the launch/event articles, as more go through for live coverage on the forum). Main EM thread now at 512,000 views, but it's organically rising in tandem with the article boost.

One more for the "Yeah right - doubt it" camp.

It's too easy to fall into the trap of thinking "But just imagine...".  No surprise that the stats stack up that way.

I'm sceptical, but have no way of arguing one way or the other.  Keep the ISS in orbit and I'll start allowing myself some excitement.  Until then, I'll keep following those space saga's that are more likely to achieve real results.

Why don't I believe without even looking at the data?  Well, you've just got to come and hit me in the face with it - sorry.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tea monster on 04/30/2015 01:11 PM
Page 21 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf

Thanks for the answer Chris. My applogies, I should have been more specific, I meant the one that's labled 'Warpstar 1' and looks (probably more accurately) like the main cabin of the Fireball XL5. Sorry for the confusion.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/30/2015 01:16 PM
Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

Just passed 30,000 reads. About 10 percent follow through into the EM Drive threads, which is standard for an article (bar the launch/event articles, as more go through for live coverage on the forum). Main EM thread now at 512,000 views, but it's organically rising in tandem with the article boost.

One more for the "Yeah right - doubt it" camp.

It's too easy to fall into the trap of thinking "But just imagine...".  No surprise that the stats stack up that way.

I'm sceptical, but have no way of arguing one way or the other.  Keep the ISS in orbit and I'll start allowing myself some excitement.  Until then, I'll keep following those space saga's that are more likely to achieve real results.

Why don't I believe without even looking at the data?  Well, you've just got to come and hit me in the face with it - sorry.

To be honest, I expected a LOT more of that sort of comment, especially on an unforgiving (mean that in the best possible way) hardcore space site like ours.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 04/30/2015 01:18 PM
CNet has a loving little article (albeit a bit hyped IMHO) regarding the NSF article and associated thread this morning.  They even reached out to Paul March (poor guy, I hope we didn't ruin his day) for a quote.

http://www.cnet.com/news/nasa-tests-physics-defying-method-of-space-travel-em-drive/

I read that earlier & it's by far the best article I've seen of the ones generated by this site's coverage of the matter.

As a general comment the only way sceptics on mass are going to be persuaded is data, more data & yet more data. It wouldn't be the first time in science that an idea has taken the long route to general acceptance.:D
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Lampyridae on 04/30/2015 01:29 PM
20 years ago, astronomers thought there were two options with regard to expansion.

1. Expansion will slow and reverse into the Big Crunch.
2. Expansion will slow but just keep on going.

I don't think anyone seriously expected what we know accept as the truth. That's science for you - 99.9% of the time it's business as usual with a few corrections and the rest it decides to kick over the tea cart.

But, I got excited with the Mach Effect before and that didn't really prove anything conclusive. So let's just wait and see. More bucks, maybe we'll get our Buck Rogers and his antigravity ship.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WBY1984 on 04/30/2015 01:38 PM
I've been looking around the various 'news' stories being thrown around in the wake of the NSF article, some of it very silly and sensationaliist.
The Eagleworks team seem to be decent people, I hope that they don't get reprimanded by 'the higher ups' over letting this stuff out into the popular consciousness. NASA has a vested interest in appearing non-kooky after all, and the way this is being reported by the tabloid end of the media spectrum is contrary to that.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 04/30/2015 01:43 PM

I've been looking around the various 'news' stories being thrown around in the wake of the NSF article, some of it very silly and sensationaliist.
The Eagleworks team seem to be decent people, I hope that they don't get reprimanded by 'the higher ups' over letting this stuff out into the popular consciousness. NASA has a vested interest in appearing non-kooky after all, and the way this is being reported by the tabloid end of the media spectrum is contrary to that.

NASA cannot be held responsible for the silliness of aspects of the Internet.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/30/2015 01:44 PM
I've been looking around the various 'news' stories being thrown around in the wake of the NSF article, some of it very silly and sensationaliist.
The Eagleworks team seem to be decent people, I hope that they don't get reprimanded by 'the higher ups' over letting this stuff out into the popular consciousness. NASA has a vested interest in appearing non-kooky after all, and the way this is being reported by the tabloid end of the media spectrum is contrary to that.

To be fair it was well before this article. This isn't the first article on EM Drive. The difference is this "mainstream" sites are now linking to this latest article, so while they may still be using their tabloid angle, they are at least sending people who click through to us a more sane article to read.

The result is more sanity than Star Trek overall.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 04/30/2015 01:51 PM

I've been looking around the various 'news' stories being thrown around in the wake of the NSF article, some of it very silly and sensationaliist.
The Eagleworks team seem to be decent people, I hope that they don't get reprimanded by 'the higher ups' over letting this stuff out into the popular consciousness. NASA has a vested interest in appearing non-kooky after all, and the way this is being reported by the tabloid end of the media spectrum is contrary to that.

To be fair it was well before this article. This isn't the first article on EM Drive. The difference is this "mainstream" sites are now linking to this latest article, so while they may still be using their tabloid angle, they are at least sending people who click through to us a more sane article to read.

The result is more sanity than Star Trek overall.

It has also caused more pictures of the late Leonard Nimoy as Mr Spock to appear online around some articles. I'm sure Mr Nimoy would have approved.:)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WBY1984 on 04/30/2015 01:51 PM

NASA cannot be held responsible for the silliness of aspects of the Internet.

I'm not talking about being held responsible, I'm talking about image. I'm talking about them not appreciating being exposed to something that if proven to not work out, they'll look like they're indulging in fringe science, regardless of it being legitimate research or not.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 04/30/2015 01:53 PM

NASA cannot be held responsible for the silliness of aspects of the Internet.

I'm not talking about being held responsible, I'm talking about image. I'm talking about them not appreciating being exposed to something that if proven to not work out, they'll look like they're indulging in fringe science, regardless of it being legitimate research or not.

But isn't it NASA's job to be on the bleeding edge of science in these areas and sometimes that works out and sometimes it doesn't when it comes to their reputation.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 04/30/2015 02:02 PM
Page 21 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf

Thanks for the answer Chris. My applogies, I should have been more specific, I meant the one that's labled 'Warpstar 1' and looks (probably more accurately) like the main cabin of the Fireball XL5. Sorry for the confusion.
The picture of "Warpstar 1"

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=782189;image)

was posted by Paul March (an engineer at NASA Eagleworks) in the EM Drive thread

see: https://forum.nasaspaceflight.com/index.php?topic=36313.msg1331771#msg1331771

In his own words:

Quote
I have no doubt now that this quantum vacuum derived propulsion system will be able to meet and ultimately surpass my conjectured WarpStar-I concept vehicle performance that I wrote about in my STAIF-2007 paper based on Woodward's Mach Lorentz Thrusters (MLT) of the day.  A vehicle that could go from the surface of the Earth to the surface of the Moon with a crew of two and six passengers with luggage in under four hours and then return to the surface of the Earth in another 4 hours with the same payload using just one load of H2/O2 fuel cell derived electrical power assuming 500-to-1,000 N/kWe efficiency MLTs or Q-Thrusters.  And yes, I know that's a mighty big leap from the 1.0uN/Watt we currently have demonstrated at the Eagleworks Lab, but if Dr. White's QVF/MHD conjecture is anywhere close to reality, it will be doable, at least in the long term.

Best, Paul M.

Note that Paul's statement

" I know that's a mighty big leap from the 1.0uN/Watt we currently have demonstrated at the Eagleworks Lab"

refers to the measured force in a vacuum per input electric power at NASA Eagleworks.  The highest measured force per input power was 1 Newton/kiloWatt for the experiments by Prof. Yang in China with a non-superconducting truncated cone EM Drive and by Cannae LLC in the USA for their superconducting EM Drive shaped like a pillbox.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RonM on 04/30/2015 02:05 PM
Absolutely fascinating to see the reaction on twitter (which is the "tough crowd" on the internet). About five percent "yeah right - doubt it", 20 percent "sceptical, but interesting", 25 percent "cool!", 25 percent "very interesting" and 25 percent "OMG!" ;D

Just passed 30,000 reads. About 10 percent follow through into the EM Drive threads, which is standard for an article (bar the launch/event articles, as more go through for live coverage on the forum). Main EM thread now at 512,000 views, but it's organically rising in tandem with the article boost.

One more for the "Yeah right - doubt it" camp.

It's too easy to fall into the trap of thinking "But just imagine...".  No surprise that the stats stack up that way.

I'm sceptical, but have no way of arguing one way or the other.  Keep the ISS in orbit and I'll start allowing myself some excitement.  Until then, I'll keep following those space saga's that are more likely to achieve real results.

Why don't I believe without even looking at the data?  Well, you've just got to come and hit me in the face with it - sorry.

That's a good attitude. The results from these experiments are contrary to current accepted theory, so all possible experimental error needs to be eliminated. If the experiments eventually show a result that cannot be ignored, then it's time for the theorists to get to work. That's science.

In the meantime, if engineers can build devices that product usable thrust and are more efficient that current thrusters, we don't have to wait for theory to use them.

Great article guys!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 04/30/2015 02:11 PM

It has also caused more pictures of the late Leonard Nimoy as Mr Spock to appear online around some articles. I'm sure Mr Nimoy would have approved.:)

"Fascinating" ;D


NASA cannot be held responsible for the silliness of aspects of the Internet.

I'm not talking about being held responsible, I'm talking about image. I'm talking about them not appreciating being exposed to something that if proven to not work out, they'll look like they're indulging in fringe science, regardless of it being legitimate research or not.

I can understand that, but at the same time if you e-mail NASA PAO and ask them for a picture of SLS, they'll show you an all-white vehicle and complain to you when you use your own artists to show it's actually got an orange core like the Shuttle ET - which is 100 percent the case (and we know they will soon change their official images to reflect).

Very loose answer, but NASA's "image" isn't even consistent internally, so if they "appreciate" this or not is not really my over-riding concern.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Semmel on 04/30/2015 02:21 PM
I go with "Extraordinary claims require extraordinary evidence". The claim here defies known laws of physics. Therefore, the evidence must be very conclusive. So far, the evidence is enough to support further investigation, but not enough to believe the claim is true. As exciting as this is, there are tons of examples where extraordinary claims were crumbled to dust. Most recently: faster than light neutrinos, primordial gravitational waves, etc.

There are some extraordinary claims that came true though, bending of light through gravity, microwave background, etc. But these examples are VERY rare. Far rare than extraordinary claims that could not have been supported. So I will remain skeptical until there is really conclusive evidence. But I absolutely support the idea to generate this evidence, or at least try to.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tea monster on 04/30/2015 03:41 PM
Supposing for a moment that this does actually work and space travel is eventually simpler than travelling between continents at the moment, it's going to highlight a few questions.

If you can zoom around the solar system using the product of an afternoon in the High School Metal Shop, then why haven't we been awash in vistors from nearby star systems?

Secondly, how much acceleration could this thing conceivably kick out? If you pour juice into it will it just keep accelerating? What's the limit to that? How many G's can it sustain and for how long? Are we looking at a torchship, but just without the torch?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 04/30/2015 04:04 PM
To be honest, I expected a LOT more of that sort of comment, especially on an unforgiving (mean that in the best possible way) hardcore space site like ours.
Perhaps it's because quite a lot of the people here have to measure stuff for a living and understand how thorough Dr White and his team have been to rule out experimental artifacts. AFAIK the sensationalist comments have been made by various parts of the media, IOW everyone but Dr White and his team.

The general level of physics knowledge here is also good enough to limit the number "Well I don't know much but this can't possibly work" comments.

Instead they are more likely to be specific objections, which can be quantified or demonstrated to be irrelevant. Answering such questions only strengthens the idea.

Note that teams in at least three countries using two different microwave sources and four cavity designs (as it's doubtful any were exact copies of the others) have all produced force readings.

Could they all be suffering some kind of collective delusion that makes them all ignore some major source of experimental error?  :(

Almost anything's possible, but does that sound a plausible explanation for what's been reported?

Time (and ever tighter experimental protocols) will tell.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 04/30/2015 04:11 PM
There are several questions in this thread regarding the issue of free energy and the issue of acceleration. 

If the quantum vacuum is immutable and not degradable, as understood by mainstream physicists, Dr. White's conjecture is not viable.  Dr. White et.al. argues that the quantum vacuum is mutable and degradable, this is his latest paper arguing this:  http://hdl.handle.net/2060/20150006842 (it just came out in http://ntrs.nasa.gov/  days ago, I don't know whether it was submitted to any peer-reviewed journal).

Now, momentum and energy are mixed together in general relativity in the stress-energy tensor http://en.wikipedia.org/wiki/Stress%E2%80%93energy_tensor which contains, momentum density, energy density, momentum flux, shear stress and pressure components.  If the quantum vacuum would be degradable as conjectured by Dr.White, then, if one can extract momentum from it, one should also be able to extract energy from it, as has been repeatedly pointed out.  A very loose (and admittedly imperfect) analogy is using air for sailing (extracting momentum)  and air for windmills (extracting energy).  This is clearly not a mainstream physics concept, because if the quantum vacuum would behave that way, it would no longer be the zero-point energy (a term probably first used by Einstein), as one should not be able to extract energy from the lowest possible quantum state.

Dr. White apparently argues that the quantum vacuum may contain different levels of "lowest" energy, depending on the applied electromagnetic field, the proximity of matter, etc., and not a universal "zero-point energy".  He has also resorted to using 5 dimensional branes from string theory.  In any case, he argues for the EM Drive system to be an open system.  Paradoxes will also occur if one performs analysis for a sailing boat as a closed system, ignoring the power from the wind, as it is able to accelerate without any engine power.  To what extent one would be able to extract momentum or energy from the quantum vacuum is highly conjectural at this point, and it is difficult to discuss the consequences of such a non-mainstream conjecture.

Concerning the acceleration I agree with several posters that it is unlikely that one would be able to accelerate "forever" (if at all), just like extracting momentum and energy from open systems (using the wind, or the ocean, or the power from the Sun) necessarily runs into nature's constraints. 

Besides Dr. White's conjecture, there are several other possible explanations for what is at play here (ranging from an experimental artifact to a possible means of space propulsion based on an anisotropic nonlinearity of the quantum vacuum).

Rather than engage too deeply into conjectures (which unfortunately a lot of physics nowadays is, for example string theory and the multiverse), I agree that the best thing to do is to closely examine the experimental data in the US, the UK and China, and perform more, better, consistent experiments, replicated at separate centers (NASA Glenn?, JPL ?)  :).

Quote from: Richard P. Feynman
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 04/30/2015 04:17 PM
Supposing for a moment that this does actually work and space travel is eventually simpler than travelling between continents at the moment, it's going to highlight a few questions.

If you can zoom around the solar system using the product of an afternoon in the High School Metal Shop, then why haven't we been awash in vistors from nearby star systems?
You're confusing 2 different projects that Eagleworks is researching.

This thing is a propellentless drive, that accelerates a vehicle without propellant. It will not exceed the speed of light. The study of space warping as a drive system, is the other project they are working on.

And if you can run up a 1MW nuclear reactor in an HS Metal shop more power to you.  :)
Quote
Secondly, how much acceleration could this thing conceivably kick out?
How good is your maths? A target figure for a developed version is 1 Newton /Kw of electricity.
Quote
If you pour juice into it will it just keep accelerating? What's the limit to that? How many G's can it sustain and for how long? Are we looking at a torchship, but just without the torch?
No. Read the article and most of your questions will be answered.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: punder on 04/30/2015 04:25 PM
There are several questions in this thread regarding the issue of free energy and the issue of acceleration. 

The various posts here predicting what amounts to perpetual motion machines are, how shall I say it, distressing.  Are these posters misinterpreting something, or is violation of conservation of energy really a possible outcome?  Thanks.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 04/30/2015 04:33 PM
Before we gets lots of questions about terrestrial applications.

Quote
18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

http://emdrive.com/faq.html
Oookaaaay. So I start up my 1000kg hover car, in Ecuador, in the spring, and I'm going to work, at the sunrise.

See any problem with that?

Let me spell it out just in case: unless this drive is pushing against Earth, Earth's orbital energy is increasing at a rate of about 300 megawatts (according to the Sun's rest frame).

Worse if taking Sun's motion around the centre of the galaxy.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 04/30/2015 04:35 PM
I go with "Extraordinary claims require extraordinary evidence". The claim here defies known laws of physics. Therefore, the evidence must be very conclusive. So far, the evidence is enough to support further investigation, but not enough to believe the claim is true. As exciting as this is, there are tons of examples where extraordinary claims were crumbled to dust. Most recently: faster than light neutrinos, primordial gravitational waves, etc.

There are some extraordinary claims that came true though, bending of light through gravity, microwave background, etc. But these examples are VERY rare. Far rare than extraordinary claims that could not have been supported. So I will remain skeptical until there is really conclusive evidence. But I absolutely support the idea to generate this evidence, or at least try to.

     At present, I'd definately say that this project has passed well beyond the "Cold Fusion" bench mark into the "Something interesting is going on" territory.  Nobody's really quite sure WHAT exactly is causing the results, but it appears to be controllable, repeatable and varies in output due to both power input variations as  a modulated signal.

    While at first glance, one could be expected to write the phenomena off as "Electric Wind" or heating of the air, as this experiment has been tested in a vacume with the same results, this explaination becomes a nonsequitor.

     If the phenomena is confirmed in the next round of tests, and a test in orbit is attempted, and, if my suspicions about the nature of the phenomena are correct, then it is quite possible that, the further up the gravity well that this device goes, the more efficiently it will work, producing more "thrust" for less power.  Also, if my conjecture holds up, the optical varience with the interferometer in space should also increase the farther out of the gravity well the test item goes.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: lcs on 04/30/2015 04:38 PM
 
Quote
The various posts here predicting what amounts to perpetual motion machines are, how shall I say it, distressing.  Are these posters misinterpreting something, or is violation of conservation of energy really a possible outcome?  Thanks.

Quoting 'papers' which have not been peer-reviewed, published, presented before a skeptical, disinterested audience, etc. etc. is of little value beyond this limited enclave of sci-fi enthusiasts. 
 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: arachnitect on 04/30/2015 04:41 PM
There are several questions in this thread regarding the issue of free energy and the issue of acceleration. 

The various posts here predicting what amounts to perpetual motion machines are, how shall I say it, distressing.  Are these posters misinterpreting something, or is violation of conservation of energy really a possible outcome?  Thanks.

It breaks conventional physics no matter what. If it breaks something too obvious, they adjust the theory to break something else instead.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Davinator on 04/30/2015 04:42 PM
Before we gets lots of questions about terrestrial applications.

Quote
18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

http://emdrive.com/faq.html
Oookaaaay. So I start up my 1000kg hover car, in Ecuador, in the spring, and I'm going to work, at the sunrise.

See any problem with that?

Let me spell it out just in case: unless this drive is pushing against Earth, Earth's orbital energy is increasing at a rate of about 300 megawatts (according to the Sun's rest frame).

Worse if taking Sun's motion around the centre of the galaxy.

We should be discussing the article, not an external link that we have nothing to do with.  Star One seems addicted to posting as many links as his fingers will allow him! ;D
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: watermod on 04/30/2015 04:46 PM
If one assumes it does work, what would it cost to make a heavily instrumented small sat test bed and carry it up as a secondary payload on an ISS or commercial launch?

Sort of a sink or swim test.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: indigodarkwolf on 04/30/2015 04:47 PM
@Rodal
This is the kind of information I was hoping to see more of in the article.

The analogy I've latched onto is a boat motor, pushing against the quantum vacuum the way a propeller would push against water. The idea of a sailboat and wind, instead, is interesting but I'm struggling with how it would introduce limits to the technology. A sailboat has a maximum speed determined by "however hard the wind blows, versus the resistance of the ocean". But it's hard to understand how there would be a resistance factor to prevent arbitrary acceleration, or a maximum "velocity" of the quantum vacuum since we would always be thinking in a reference frame relative to the Emdrive. Wouldn't an Emdrive always be able to extract force from the quantum vacuum, regardless of velocity relative to an object?

Unless the medium we're pushing against is, itself, a product of another object in space. I wonder if there's a shoestring way to experimentally determine whether the medium that the Emdrive is acting on is a product of, or dragged along by, the Earth itself.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Norm Hartnett on 04/30/2015 04:47 PM

Quote
The various posts here predicting what amounts to perpetual motion machines are, how shall I say it, distressing.  Are these posters misinterpreting something, or is violation of conservation of energy really a possible outcome?  Thanks.

Quoting 'papers' which have not been peer-reviewed, published, presented before a skeptical, disinterested audience, etc. etc. is of little value beyond this limited enclave of sci-fi enthusiasts. 
 

Yes, I wish that the entire "Applications" section of the article had been omitted, not really up to NSF standards. EM may be viable but it is difficult to evaluate when it comes with such wildly speculative window dressing.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: nadreck on 04/30/2015 04:48 PM
So, I was 100% skeptic, and save having glanced at the EM Thread a couple of times because of it's high traffic, I was not taking it any more seriously than I currently take Ponds/Fleischmann's stuff. However, I was interested and hopeful when Ponds/Fleischmann's work hit the news way back when, but it failed to be reproducible.  When Chris Bergin (thanks man!) brought attention to it again a week or so ago I delved much deeper in to the thread and then gobbled up the article that came out. Now I am interested and hopeful, but also I don't need to be skeptical because this seems something that can be verified experimentally and is being. As far as I can tell, there is enough information out there for many groups to experiment. I think that if this attention from NSF has done anything, it has brought the attention of a lot of people who could work on verifying this to the topic and in a way that is surprisingly supportive.

What I do presume is that whatever force interactions are at play in the results to date is that what has been seen seems to indicate that rethinking underlying principles of physics (which we have had to do before) is required. Also what is observed seems to be applicable to spacecraft.  So on with more research, please!

I would like to remind the readers of SF of James Blish's Cities in Flight where a new space drive technology was quite simple and easy to build, but that verifying and understanding the physics of it became mankind's largest Giga project.  However this works out in the end, I don't think any of us have any certainty of how that will be.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: indigodarkwolf on 04/30/2015 04:49 PM
If one assumes it does work, what would it cost to make a heavily instrumented small sat test bed and carry it up as a secondary payload on an ISS or commercial launch?

Sort of a sink or swim test.
What's the cheapest EM spacecraft design that should do clearly impossible things?

About $10,000. You could Kickstarter it and get it on the next Dragon flight, ala A3R (http://en.wikipedia.org/wiki/Planetary_Resources#Arkyd_3_Flight_test_system). Heck, there's cubesats that have flown for less.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mongo62 on 04/30/2015 05:04 PM
There are several questions in this thread regarding the issue of free energy and the issue of acceleration. 

The various posts here predicting what amounts to perpetual motion machines are, how shall I say it, distressing.  Are these posters misinterpreting something, or is violation of conservation of energy really a possible outcome?  Thanks.

I have read those objections. They all seem to be working from an unstated assumption: that the device produces a constant thrust and therefore acceleration for a given power input. If that were the case, then the kinetic energy would indeed eventually exceed the total input of energy into the drive.

So the obvious solution is that for a given energy input, thrust is not linear, but delta kinetic energy is linear instead. So as the kinetic energy increases, the thrust for a given power input would decrease, but the kinetic energy imparted would continue to increase at a steady rate over time.

This would mean that there must be a local reference frame for the velocity and hence kinetic energy to me measured against, which contradicts standard SR but is in agreement with some more recent relativistic theories.

This would also mean that trip times for a given input energy would be longer than in the article, but you still avoid the negative effects of the rocket equation, so they remain a lot better than with conventional propulsion.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: chipguy on 04/30/2015 05:13 PM
I think the article should have stuck with the new test results and a brief history of research in this area. This whole "warpstar-1" extrapolation of an EM drive equipped craft could " travel from the surface of Earth to the surface of the moon within four hours" when even unambiguously measuring any thrust at all under lab conditions is problematic is just way too far out there and does disservice to this site.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 04/30/2015 05:18 PM
There are several questions in this thread regarding the issue of free energy and the issue of acceleration. 

The various posts here predicting what amounts to perpetual motion machines are, how shall I say it, distressing.  Are these posters misinterpreting something, or is violation of conservation of energy really a possible outcome?  Thanks.

I have read those objections. They all seem to be working from an unstated assumption: that the device produces a constant thrust and therefore acceleration for a given power input. If that were the case, then the kinetic energy would indeed eventually exceed the total input of energy into the drive.

So the obvious solution is that for a given energy input, thrust is not linear, but delta kinetic energy is linear instead. So as the kinetic energy increases, the thrust for a given power input would decrease, but the kinetic energy imparted would continue to increase at a steady rate over time.

This would mean that trip times for a given input energy would be longer than in the article, but you still avoid the negative effects of the rocket equation, so they remain a lot better than with conventional propulsion.
1 m/s^2 acceleration of 1kg object, according to an observer moving in the direction of the rear of the drive, at 1 meter per second, is raising the kinetic energy at an instantaneous rate of 1 joule per second (1 watt). According to an observer moving at the velocity of 1km/s , by 1000 watts .  Which observer is correct?

Keep in mind that anything stationary on Earth is moving at hundreds kilometres per second relatively to, say, cosmic microwave background, or any other such frame of reference than you could pick as preferred.

If you were to try to build a theory it would have to simultaneously produce such thrust and not alter the behaviour of microwaves in any equipment ever built sufficiently for someone to have gone "that's funny, why is this device's parameters vary as a sine wave in the course of a day?"
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 04/30/2015 05:20 PM
If one assumes it does work, what would it cost to make a heavily instrumented small sat test bed and carry it up as a secondary payload on an ISS or commercial launch?

Sort of a sink or swim test.
The problem with that would be the power requirement.

Dr White's test setup produces something around 50-80 x 10^-6 N of force for 100w of input.

The last time I checked triple junction PV cells have hit 43% and thin film types around 16%. A 4 wing roll out design would need 4 wings 10cm x about 1.3m, or 18 10x10cm plates of rigid plates.

Either way you're looking at a fairly tricky mechanism construction job to unfold enough array to be useful.  :(
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 04/30/2015 05:24 PM
Yeah... I'm not getting how this does not violate conservation of momentum and energy. For example if this works you should be able to construct a perpetual motion free energy machine. If constant electrical power produces constant acceleration you have a problem since kinetic energy increases with the square of velocity. You will quickly reach a point where your kinetic energy vastly exceeds the electrical energy input.

Sorry, I smell the stench of cold fusion. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mongo62 on 04/30/2015 05:30 PM
Yeah... I'm not getting how this does not violate conservation of momentum and energy. For example if this works you should be able to construct a perpetual motion free energy machine. If constant electrical power produces constant acceleration you have a problem since kinetic energy increases with the square of velocity. You will quickly reach a point where your kinetic energy vastly exceeds the electrical energy input.

Sorry, I smell the stench of cold fusion.

Again, as I said above, why are you assuming constant acceleration? Constant increase in kinetic energy would eliminate this objection, at the cost of requiring a fixed inertial reference frame to measure the kinetic energy against. Standard special relativity theory does not allow this, but some newer theories that are equivalent to special relativity in their observed effects do allow this.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 04/30/2015 05:37 PM
There is one joker in the pack. It seems force produced falls as the payload accelerates, so this is an engine with a "top speed" limit.

This would be a violation of Lorentz invariance of spacetime wrt boosts: laws of physics would not be the same in different reference frames moving relative to each other. This is a VERY tall claim.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 04/30/2015 05:37 PM
If one assumes it does work, what would it cost to make a heavily instrumented small sat test bed and carry it up as a secondary payload on an ISS or commercial launch?

Sort of a sink or swim test.
The problem with that would be the power requirement.

Dr White's test setup produces something around 50-80 x 10^-6 N of force for 100w of input.

The last time I checked triple junction PV cells have hit 43% and thin film types around 16%. A 4 wing roll out design would need 4 wings 10cm x about 1.3m, or 18 10x10cm plates of rigid plates.

Either way you're looking at a fairly tricky mechanism construction job to unfold enough array to be useful.  :(

Ok if acceleration is not constant (The article implied that it is.) then you are creating a preferred frame of reference in violation of relativity. That would mean the laws of physics would change depending on your inertial frame. Not a good thing.

And you are still violating conservation of momentum.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 04/30/2015 05:37 PM
If one assumes it does work, what would it cost to make a heavily instrumented small sat test bed and carry it up as a secondary payload on an ISS or commercial launch?

Sort of a sink or swim test.
The problem with that would be the power requirement.

Dr White's test setup produces something around 50-80 x 10^-6 N of force for 100w of input.

The last time I checked triple junction PV cells have hit 43% and thin film types around 16%. A 4 wing roll out design would need 4 wings 10cm x about 1.3m, or 18 10x10cm plates of rigid plates.

Either way you're looking at a fairly tricky mechanism construction job to unfold enough array to be useful.  :(

Just stick it in a shielded hermetic box, powered off a RC airplane battery on a timer, hang it off a hanging Cavendish style torsion pendulum (insensitive to shifts in CoM), and test it in different orientations to rule out magnetic effects. You'd be easily able to get all the drifts into sub-micronewton range with a fully shielded set up.

That's a lot cheaper than a satellite and a positive result would be much more convincing.

edit: a couple hundred grams of lithium batteries (non rechargeable) and 1kg of ice (for sinking heat while keeping temperature constant, if needed) would allow for 50 minutes of operation at 100 watts.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tchernik on 04/30/2015 05:46 PM
If one assumes it does work, what would it cost to make a heavily instrumented small sat test bed and carry it up as a secondary payload on an ISS or commercial launch?

Sort of a sink or swim test.
The problem with that would be the power requirement.

Dr White's test setup produces something around 50-80 x 10^-6 N of force for 100w of input.

The last time I checked triple junction PV cells have hit 43% and thin film types around 16%. A 4 wing roll out design would need 4 wings 10cm x about 1.3m, or 18 10x10cm plates of rigid plates.

Either way you're looking at a fairly tricky mechanism construction job to unfold enough array to be useful.  :(

Just stick it in a shielded hermetic box, powered off a RC airplane battery on a timer, hang it off a hanging Cavendish style torsion pendulum (insensitive to shifts in CoM), and test it in different orientations to rule out magnetic effects. You'd be easily able to get all the drifts into sub-micronewton range with a fully shielded set up.

That's a lot cheaper than a satellite and a positive result would be much more convincing.

That will happen. This is not a secret technology controlled by a single guy claiming it works, or anything like that. The data on how to build one is in the open, accessible and feasible to replicate for anyone with enough resources and technical ability to do so.

And given its "eppur si muove" type claims, it will unavoidably emerge to the light if it works or not, as long as people keep an open and transparent review process for the test setup and the results.

 And as more people perform replications on their own, they will certainly try this. So I'm really hopeful because we will soon known if it works, of if it was just a waste of time. Either way, we win (a revolutionary invention, or just knowledge).

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 04/30/2015 05:58 PM
Yeah... I'm not getting how this does not violate conservation of momentum and energy. For example if this works you should be able to construct a perpetual motion free energy machine. If constant electrical power produces constant acceleration you have a problem since kinetic energy increases with the square of velocity. You will quickly reach a point where your kinetic energy vastly exceeds the electrical energy input.

Sorry, I smell the stench of cold fusion.

Again, as I said above, why are you assuming constant acceleration? Constant increase in kinetic energy would eliminate this objection, at the cost of requiring a fixed inertial reference frame to measure the kinetic energy against. Standard special relativity theory does not allow this, but some newer theories that are equivalent to special relativity in their observed effects do allow this.

The observed effects are that laws of physics are invariant relative to Lorentz boosts. Maxwell equations of electromagnetism are explicitly invariant relative to Lorentz boosts. This is a purely electromagnetic device. Which part of Maxwell equations is wrong?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: M Gibbons on 04/30/2015 06:01 PM
Quote
The problem with that would be the power requirement.

Dr White's test setup produces something around 50-80 x 10^-6 N of force for 100w of input.

The last time I checked triple junction PV cells have hit 43% and thin film types around 16%. A 4 wing roll out design would need 4 wings 10cm x about 1.3m, or 18 10x10cm plates of rigid plates.

Either way you're looking at a fairly tricky mechanism construction job to unfold enough array to be useful.

Perhaps the Dragon trunk section could be used as a platform for the test after separation from the capsule.  I suppose this would require the addition of thrusters of some kind to control the orientation of the solar panels.  Probably more effort than a dedicated satellite, but just a thought.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 04/30/2015 06:07 PM

Before we gets lots of questions about terrestrial applications.

Quote
18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

http://emdrive.com/faq.html
Oookaaaay. So I start up my 1000kg hover car, in Ecuador, in the spring, and I'm going to work, at the sunrise.

See any problem with that?

Let me spell it out just in case: unless this drive is pushing against Earth, Earth's orbital energy is increasing at a rate of about 300 megawatts (according to the Sun's rest frame).

Worse if taking Sun's motion around the centre of the galaxy.

We should be discussing the article, not an external link that we have nothing to do with.  Star One seems addicted to posting as many links as his fingers will allow him! ;D

I posted it in response to a question that was asked and to stop the question being repeated and derailing the thread.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Cherokee43v6 on 04/30/2015 06:07 PM
Quote
The problem with that would be the power requirement.

Dr White's test setup produces something around 50-80 x 10^-6 N of force for 100w of input.

The last time I checked triple junction PV cells have hit 43% and thin film types around 16%. A 4 wing roll out design would need 4 wings 10cm x about 1.3m, or 18 10x10cm plates of rigid plates.

Either way you're looking at a fairly tricky mechanism construction job to unfold enough array to be useful.

Perhaps the Dragon trunk section could be used as a platform for the test after separation from the capsule.  I suppose this would require the addition of thrusters of some kind to control the orientation of the solar panels.  Probably more effort than a dedicated satellite, but just a thought.

Why not as part of a Dragonlab mission?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 04/30/2015 06:09 PM
There are several questions in this thread regarding the issue of free energy and the issue of acceleration. 

The various posts here predicting what amounts to perpetual motion machines are, how shall I say it, distressing.  Are these posters misinterpreting something, or is violation of conservation of energy really a possible outcome?  Thanks.

It breaks conventional physics no matter what. If it breaks something too obvious, they adjust the theory to break something else instead.

Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time. And yet we obviously do (at least locally) exist as beings of matter and thus equivalent energy. It follows logically that net energy can (at least locally) be 'created' - most likely from the quantum vacuum. What kind of physical process this is, we don't know yet. Going by the simple observation that energy exists, there should logically exist a physical process to locally generate net energy from the quantum vacuum. I mean, we can't just ignore all existing matter and energy and still claim that neither of them should be able to come to be.  ;)

I think that time will tell whether or not we have a propulsion system here that can also draw usable energy from higher dimensions or whatever as a byproduct. For now, the only thing that makes sense is to do the experiments and follow the data.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TomH on 04/30/2015 06:15 PM
Skepticism and Closed Mindedness are not the same thing. The first is an important frame of mind in scientific investigation; the second is antithetical to science.

At the close of the 19th century, virtually every physicist alive was of the belief that everything that could be learned about physics was already known. As described in Thomas S. Kuhn's The Structure of Scientific Revolutions, the world of physics was about to be turned on its head. There were more than a few who accepted neither Relativity nor Quantum Mechanics. The skeptics needed to see the proof, but a skeptic examines evidence and accepts it if reasonable. A closed minded person refuses to abandon old models, in spite of new evidence to the contrary.

For over a century now, physics has found itself in limbo, a no man's land of seemingly irreconcilable contradiction between Relativity and Quantum Mechanics. Much has been learned and new discoveries continue to happen, but there is not yet a Unified Field Theory, nor a Grand Unified Field Theory, nor a Theory of Everything (each of those has a different meaning). String Theory is the leading candidate at the moment, yet there are over ten differing models of how String Theory might work. The theory of Loop Quantum Gravity is the second favored theory, and then there are lesser known theories such as Garrett Lisi's E8 Theory.

What we understand about the fabric of spacetime, about the Quantum Vacuum is still very limited. We do, however, know that it is something and not nothing. And yet we do not need fully to understand a phenomenon in order to make use of it. Roentgen put X-Rays to use long before the mechanism behind their production was understood. In like manner, it is entirely possible that EM Drive may work and that it may be put to use before the entirity of the physics behind it is fully understood.

Reactions in this thread range from exuberance to completely closed minds. Science is not about jumping to conclusions, either that a theory is correct or that it is incorrect. Science is about approaching a hypothesis with an open mind, a neutrality regarding belief. It embraces a healthy skepticism for results that tend to be extreme outliers, but does accept them if they are shown to be independently repeatable by other scientists.

We used to ask whether the expanding universe had enough inertia to continue expanding forever at a decreasing rate, or if it would stop expanding and all mass implode into one singularity. Only recently did we discover the inflation is ocurring at an accelerating rate, leading us to theorize Dark Energy. It is all about the evidence. We have to follow the evidence. Whether we think this is the next great breakthrough in science or whether we think this is absurd, neither matters. This is not about opinion. What matters is the evidence. At present, there is no proof this is impossible, and there is no proof it is possible. We have to follow the evidence.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 04/30/2015 06:21 PM
If one assumes it does work, what would it cost to make a heavily instrumented small sat test bed and carry it up as a secondary payload on an ISS or commercial launch?

Sort of a sink or swim test.
The problem with that would be the power requirement.

Dr White's test setup produces something around 50-80 x 10^-6 N of force for 100w of input.

The last time I checked triple junction PV cells have hit 43% and thin film types around 16%. A 4 wing roll out design would need 4 wings 10cm x about 1.3m, or 18 10x10cm plates of rigid plates.

Either way you're looking at a fairly tricky mechanism construction job to unfold enough array to be useful.  :(

Just stick it in a shielded hermetic box, powered off a RC airplane battery on a timer, hang it off a hanging Cavendish style torsion pendulum (insensitive to shifts in CoM), and test it in different orientations to rule out magnetic effects. You'd be easily able to get all the drifts into sub-micronewton range with a fully shielded set up.

That's a lot cheaper than a satellite and a positive result would be much more convincing.

That will happen. This is not a secret technology controlled by a single guy claiming it works, or anything like that. The data on how to build one is in the open, accessible and feasible to replicate for anyone with enough resources and technical ability to do so.

And given its "eppur si muove" type claims, it will unavoidably emerge to the light if it works or not, as long as people keep an open and transparent review process for the test setup and the results.

 And as more people perform replications on their own, they will certainly try this. So I'm really hopeful because we will soon known if it works, of if it was just a waste of time. Either way, we win (a revolutionary invention, or just knowledge).
Look at it from the point of view of a reasonable physicist. The theory makes little sense to them, so they treat it as a random attempt, those are very unlikely to succeed - an epsilon probability that it works.
The epsilon is pretty tiny because without a sensible theory we're shooting in the dark and are unlikely to hit the target.

So you hear of a positive from an experiment where there's, say, a 20% chance of a false positive or a false negative. Look up Bayes rule. You get p=0.8*epsilon/(0.8*epsilon+0.2*(1-epsilon)) ~= 4*epsilon after taking the experimental positive into account.

You need a good test with a low chance of a false positive to convince a reasonable skeptic.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 04/30/2015 06:29 PM
Yeah... I'm not getting how this does not violate conservation of momentum and energy. For example if this works you should be able to construct a perpetual motion free energy machine. If constant electrical power produces constant acceleration you have a problem since kinetic energy increases with the square of velocity. You will quickly reach a point where your kinetic energy vastly exceeds the electrical energy input.

Sorry, I smell the stench of cold fusion.

Again, as I said above, why are you assuming constant acceleration? Constant increase in kinetic energy would eliminate this objection, at the cost of requiring a fixed inertial reference frame to measure the kinetic energy against. Standard special relativity theory does not allow this, but some newer theories that are equivalent to special relativity in their observed effects do allow this.

The observed effects are that laws of physics are invariant relative to Lorentz boosts. Maxwell equations of electromagnetism are explicitly invariant relative to Lorentz boosts. This is a purely electromagnetic device. Which part of Maxwell equations is wrong?
Exactly. There's also very tight bounds on how wrong they can be. There's all sorts of highly sensitive electronics that works the same as Earth rotates around it's axis, around the Sun, in addition to Sun's high velocity around the centre of the Milky Way.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 04/30/2015 06:33 PM
Skepticism and Closed Mindedness are not the same thing. The first is an important frame of mind in scientific investigation; the second is antithetical to science.

At the close of the 19th century, virtually every physicist alive was of the belief that everything that could be learned about physics was already known. As described in Thomas S. Kuhn's The Structure of Scientific Revolutions, the world of physics was about to be turned on its head. There were more than a few who accepted neither Relativity nor Quantum Mechanics. The skeptics needed to see the proof, but a skeptic examines evidence and accepts it if reasonable. A closed minded person refuses to abandon old models, in spite of new evidence to the contrary.

For over a century now, physics has found itself in limbo, a no man's land of seemingly irreconcilable contradiction between Relativity and Quantum Mechanics. Much has been learned and new discoveries continue to happen, but there is not yet a Unified Field Theory, nor a Grand Unified Field Theory, nor a Theory of Everything (each of those has a different meaning). String Theory is the leading candidate at the moment, yet there are over ten differing models of how String Theory might work. The theory of Loop Quantum Gravity is the second favored theory, and then there are lesser known theories such as Garrett Lisi's E8 Theory.

What we understand about the fabric of spacetime, about the Quantum Vacuum is still very limited. We do, however, know that it is something and not nothing. And yet we do not need fully to understand a phenomenon in to make use of it. Roentgen put X-Rays to use long before the mechanism behind their production was understood. In like manner, it is entirely possible that EM Drive may work and that it may be put to use before the entirity of the physics behind it is fully understood.

Reactions in this thread range from exuberance to completely closed minds. Science is not about jumping to conclusions, either that a theory is correct or that it is incorrect. Science is about approaching a hypothesis with an open mind, a neutrality regarding belief. It embraces a healthy skepticism for results that tend to be extreme outliers, but does accept them if they are shown to be independently repeatable by other scientists.

We used to ask whether the expanding universe had enough inertia to continue expanding forever at a decreasing rate, or if it would stop expanding and all mass implode into one singularity. Only recently did we discover the inflation is ocurring at an accelerating rate, leading us to theorize Dark Energy. It is all about the evidence. We have to follow the evidence. Whether we think this is the next great breakthrough in science or whether we think this is absurd, neither matters. This is not about opinion. What matters is the evidence. At present, there is no proof this is impossible, and there is no proof it is possible. We have to follow the evidence.

It is not close mindedness to point out that violating conservation of energy and momentum create massive problems for the supposed effect. This is especially true when many of the proponents do not understand that the conservation laws are being violated or understand the consequences of those violations.

Cold fusion should have taught us to be very very skeptical of these types of revolutionary results. Instead I suspect we will see people claiming that the EM drive finally explains where the excess energy in cold fusion comes from.

It isn't impossible that there is something interesting here. It is just very very unlikely. This combination of low probability and high desire creates a strong possibility of self deception.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Cinder on 04/30/2015 06:47 PM
Let's keep in mind that we, here and now, got to this point after 100+ pages of attitude and discussion that's on the opposite end of that spectrum.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Bubbinski on 04/30/2015 06:48 PM
Many thanks to the authors of the article and to NSF.com.

I've peeked at the EM drive thread but never understood what was being talked about. I'm afraid my expertise and education are at the "caveman" level with regard to physics, but this article did a good job of making the "state of play" of this tech at least slightly more understandable for me.  *If* this works it would be a total game changer for space exploration and exploitation, and I imagine it would upend a whole bunch of assumptions about what exploration architectures to use (fuel depots, SLS, etc.).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: indigodarkwolf on 04/30/2015 06:57 PM
What I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?

Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mongo62 on 04/30/2015 07:18 PM
It is not close mindedness to point out that violating conservation of energy and momentum create massive problems for the supposed effect. This is especially true when many of the proponents do not understand that the conservation laws are being violated or understand the consequences of those violations.

You are assuming that conservation of energy or momentum would be violated. This is only true if the device (and its attached spaceship, if any) is a closed system, but the basis of the proposed theories of how it works is that it is NOT a closed system. Instead it is coupled to the quantum vacuum somehow, and the change in momentum of the device could be balanced by an equal but opposite change in the local momentum of the quantum vacuum, which could propagate from virtual particle to virtual particle in a wave-like manner (like a sound wave) until it is transfered to (possibly quite distant) non-virtual matter. Although by then the momentum transfer per unit mass would be so tiny that it would probably be quite undetectable.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TomH on 04/30/2015 07:18 PM
It is not close mindedness to point out that violating conservation of energy and momentum create massive problems for the supposed effect. This is especially true when many of the proponents do not understand that the conservation laws are being violated or understand the consequences of those violations.

Cold fusion should have taught us to be very very skeptical of these types of revolutionary results. Instead I suspect we will see people claiming that the EM drive finally explains where the excess energy in cold fusion comes from.

It isn't impossible that there is something interesting here. It is just very very unlikely. This combination of low probability and high desire creates a strong possibility of self deception.

I agree, it isn't closed minded to point that out. However it is closed minded if you believe what has been accepted as a LAW of physics can never be disproven or modified. That was the problem of many Newtonian physicists at the end of the 19th century. You are not going to prove this issue one way or the other through logic. It will only be proven by experimentation.

It's just like the transit time of Mercury across the sun. The measured time was said to be impossible because it violated accepted mathematical theory. All manner of bizarre explanations were proposed, until Einstein proved that the sun's gravity was warping spacetime in Mercury's orbit. Newtonian physics had to be altered to acommodate Special and General Relativity. Einstein was proven right via experiment when the moon's gravity warped spacetime and allowed the sun's corona to be seen during a total lunar eclipse. (The moon covers a slightly wider angle of the sky than the sun.) Thus was proven gravitational lensing.

Regarding these posters who are specualting about perpetual motion machines or machines with higher output than input, my skepticism is much greater about that than it is about the ability of EM to push against something in the Quantum Vacuum. Air turbine engines have much higher ISP than bi-propellant chemical rocket engines due to the ability of the turbofan to focus and thermally expand the air coming into the turbine. I do highly doubt that anything will violate conservation of momentum and energy. Nevertheless, a nuclear reactor might provide the energy for the EM Drive to push against something in the fabric of spacetime/Quantum Vacuum. We also do know that sub-atomic particles enter our universe, apparently out of sub-space. That violates the Law of Conservation from a certain POV. Perhaps the EM Drive may be activating some kind of potential energy in the Quantum Vacuum that we otherwise have not yet detected and changing it to kinetic energy. If so, that would not violate the Law of Conservation.

This theory will not be disproven by logic. It will only be disproven, or proven, by scientific experimentation and examination of emperical evidence. Anyone who thinks it will be proven solely by logical argument of currently known physics IS CLOSED MINDED. You have to experiment according to scientific method protocol and then you have to FOLLOW THE EVIDENCE.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Ludus on 04/30/2015 07:58 PM
What's the cheapest EM spacecraft design that should do clearly impossible things?

About $10,000. You could Kickstarter it and get it on the next Dragon flight, ala A3R (http://en.wikipedia.org/wiki/Planetary_Resources#Arkyd_3_Flight_test_system). Heck, there's cubesats that have flown for less.

This seems about right and is a major reason I'm skeptical. Lab experiments are pointless for convincing anyone. Based on everything reported it should be quite easy to put an EMdrive on a little satellite paid for by Kickstarter and get it a free ride in the trunk of a Dragon. It just has to change it's orbit in a way that according to claims should be easy for First Gen EM drive but also be impossible for any accepted technology. It should be able to keep up orbital maneuvering long after it would be impossible using any known design. This would be transparent and open to the world. Cue Nobel prize, whatever funding they want, Heinlein prize, eternal glory. What's stopping this?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 04/30/2015 08:05 PM
What I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?

Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.

It isn't clear to me what you are saying here.

Take a car. It takes four times as much energy to accelerate from 10 mph to 20 mph as it took to accelerate from zero to ten mph. A rocket has the same problem but much worse because it takes its reaction mass with it.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 04/30/2015 08:21 PM
It is not close mindedness to point out that violating conservation of energy and momentum create massive problems for the supposed effect. This is especially true when many of the proponents do not understand that the conservation laws are being violated or understand the consequences of those violations.

You are assuming that conservation of energy or momentum would be violated. This is only true if the device (and its attached spaceship, if any) is a closed system, but the basis of the proposed theories of how it works is that it is NOT a closed system. Instead it is coupled to the quantum vacuum somehow, and the change in momentum of the device could be balanced by an equal but opposite change in the local momentum of the quantum vacuum, which could propagate from virtual particle to virtual particle in a wave-like manner (like a sound wave) until it is transfered to (possibly quite distant) non-virtual matter. Although by then the momentum transfer per unit mass would be so tiny that it would probably be quite undetectable.

I'm not assuming it I'm pointing out that it appears to be violating energy and momentum. You can have it reacting against some quantum vacuum but that does not solve the problem yet. If the thing accelerates constantly you still have conservation of energy problems. If it does not then you have created a preferred frame of reference in violation of relativity.

Now you may find a way around these problems but first you need to understand that these problems exist.

I have thought about a science fiction drive that reacts against the local gravitational gradient. This would not violate energy or momentum. But that isn't a scientific theory. It is a work of fiction. Almost certainly no such device is possible.

The problem with these these cold fusion type claims is it causes us to confuse science and science fiction.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 04/30/2015 08:23 PM
Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.

The latter does not follow from the former.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 04/30/2015 08:34 PM
I agree, it isn't closed minded to point that out. However it is closed minded if you believe what has been accepted as a LAW of physics can never be disproven or modified.

Do you see anyone here saying such a stupid thing? I don't.

Quote
This theory will not be disproven by logic. It will only be disproven, or proven, by scientific experimentation and examination of emperical evidence. Anyone who thinks it will be proven solely by logical argument of currently known physics IS CLOSED MINDED. You have to experiment according to scientific method protocol and then you have to FOLLOW THE EVIDENCE.

You are not getting what we "the skeptics" are saying.

We are not saying that evidence should be ignored.

We are saying that implications of the device working as claimed are so extraordinary that fantasizing about building spaceships to Alpha Centauri is the last thing we need to do. Doing this *now* just makes one look a bit like an obsessed person.

The thing to do now is to provide extraordinary, compelling evidence. Experiment needs to be redone in a much more clean environment. Eventually, if/when tests in vacuum but on Earth seem to still show the effect, it will need to be redone in space, away from Earth magnetic field, IR radiation etc.

*THEN* the claims will be taken by most scientists very seriously.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 04/30/2015 08:38 PM
Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.

The latter does not follow from the former.

If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: indigodarkwolf on 04/30/2015 08:43 PM
What I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?

Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.

It isn't clear to me what you are saying here.

Take a car. It takes four times as much energy to accelerate from 10 mph to 20 mph as it took to accelerate from zero to ten mph. A rocket has the same problem but much worse because it takes its reaction mass with it.
A car doesn't contain reaction mass? What about gasoline?

Also, it doesn't take 4x the energy to double a car's velocity. A car has 4x the KE after doubling velocity, but that is not the same thing as saying 4x KE was required to get there.

Not to mention, the energy requirements of accelerating a car include overcoming wind resistance and friction, which resists the forward motion of the car. Maintaining a velocity against these forces is a measure of work, not energy. And since the formula for the force of drag resistance also includes V2, that means that there is 4x as much drag at 20mph as there is at 10mph, and so 4x as much work is required to maintain velocity each time you double velocity. This is still not the same thing as 4x as much energy.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Karlman on 04/30/2015 08:56 PM
(snip...)
The thing to do now is to provide extraordinary, compelling evidence. Experiment needs to be redone in a much more clean environment. Eventually, if/when tests in vacuum but on Earth seem to still show the effect, it will need to be redone in space, away from Earth magnetic field, IR radiation etc.

*THEN* the claims will be taken by most scientists very seriously.

From the article, it looks like NASA Eagleworks has replicated the results in a vacuum in the lab:
Quote
However, Paul March, an engineer at NASA Eagleworks, recently reported in NASASpaceFlight.com’s forum (on a thread now over 500,000 views) that NASA has successfully tested their EM Drive in a hard vacuum – the first time any organization has reported such a successful test.

To this end, NASA Eagleworks has now nullified the prevailing hypothesis that thrust measurements were due to thermal convection.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: coypu76 on 04/30/2015 09:12 PM
I'm not a scientist or an engineer, just a geek, so I've been reticent to post.  A couple of observations:

1. The blogosphere and various social media seem to have really jumped the shark on the "Warp drive" stuff. 

2.  Thrust in vacuum has been verified - but what was the range of thrust Eagleworks observed with 100W input?  The article says the Chinese saw ~700mN with 2.5KW input.

3.  Is the speculation about "warp drives" and such related to the interesting diffraction pattern that resembles, at least superficially, what one might expect from a warp bubble?  (a lot of other things look like concentric waves, so I think perhaps I'll limit my response to this to, "Hmm.  Interesting."

4.  Suggestions for modest space experiments:  The trunk on SpaceX's Dragon has solar cells that generate up to 5KW.  Seems to me a fairly inexpensive experiment would be to mount an EMDrive in the trunk on a pivoting frame with actuators and a telemetry/control unit.  The trunk could be used to experiment with the EMDrive after the Dragon jettisons it for re-entry. Or a mini-sat with solar cells, batteries, telemetry/control and an EMDrive test unit could easily be stowed in a Falcon 9 second stage or Dragon's trunk for deployment as a secondary mission.  Isn't it feasible that some sort of test article with control/telemetry can be crowdsourced and lofting purchased (or begged) on a mission, riding in an F9 stage 2 or Dragon's trunk?

5.  Has anyone contacted Roger Shawyer for a comment?  I'd be interested to see what he has to say about what seems to be an emerging consensus of vindication for his drive.

Thanks for allowing a mere mortal to add my 2 cents worth of questions and comments.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Cinder on 04/30/2015 09:16 PM
What's the cheapest EM spacecraft design that should do clearly impossible things?

About $10,000. You could Kickstarter it and get it on the next Dragon flight, ala A3R (http://en.wikipedia.org/wiki/Planetary_Resources#Arkyd_3_Flight_test_system). Heck, there's cubesats that have flown for less.

This seems about right and is a major reason I'm skeptical. Lab experiments are pointless for convincing anyone. Based on everything reported it should be quite easy to put an EMdrive on a little satellite paid for by Kickstarter and get it a free ride in the trunk of a Dragon. It just has to change it's orbit in a way that according to claims should be easy for First Gen EM drive but also be impossible for any accepted technology. It should be able to keep up orbital maneuvering long after it would be impossible using any known design. This would be transparent and open to the world. Cue Nobel prize, whatever funding they want, Heinlein prize, eternal glory. What's stopping this?
Insufficient characterization?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 04/30/2015 09:21 PM
(snip...)
The thing to do now is to provide extraordinary, compelling evidence. Experiment needs to be redone in a much more clean environment. Eventually, if/when tests in vacuum but on Earth seem to still show the effect, it will need to be redone in space, away from Earth magnetic field, IR radiation etc.

*THEN* the claims will be taken by most scientists very seriously.

From the article, it looks like NASA Eagleworks has replicated the results in a vacuum in the lab:
Quote
However, Paul March, an engineer at NASA Eagleworks, recently reported in NASASpaceFlight.com’s forum (on a thread now over 500,000 views) that NASA has successfully tested their EM Drive in a hard vacuum – the first time any organization has reported such a successful test.

To this end, NASA Eagleworks has now nullified the prevailing hypothesis that thrust measurements were due to thermal convection.

No the gas in a car is not reaction mass. An electric car has no gas and does the same thing. You don't seem to know what I mean by reaction mass. If you are on roller skates and throw a brick that is your reaction mass. For a car the earth is its reaction mass. That is what it is reacting against. But unlike a rocket it does not have to carry its reaction mass with it.

And a car going twice as fast has four times the Ke. That energy has to come from somewhere. Chemical, electrical whatever.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 04/30/2015 09:31 PM
What I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?

Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.

It isn't clear to me what you are saying here.

Take a car. It takes four times as much energy to accelerate from 10 mph to 20 mph as it took to accelerate from zero to ten mph. A rocket has the same problem but much worse because it takes its reaction mass with it.
A car doesn't contain reaction mass? What about gasoline?

Also, it doesn't take 4x the energy to double a car's velocity. A car has 4x the KE after doubling velocity, but that is not the same thing as saying 4x KE was required to get there.

Not to mention, the energy requirements of accelerating a car include overcoming wind resistance and friction, which resists the forward motion of the car. Maintaining a velocity against these forces is a measure of work, not energy. And since the formula for the force of drag resistance also includes V2, that means that there is 4x as much drag at 20mph as there is at 10mph, and so 4x as much work is required to maintain velocity each time you double velocity. This is still not the same thing as 4x as much energy.


Sorry, I keep replying to the wrong message.

No the gas in a car is not reaction mass. An electric car has no gas and does the same thing. You don't seem to know what I mean by reaction mass. If you are on roller skates and throw a brick that is your reaction mass. For a car the earth is its reaction mass. That is what it is reacting against. But unlike a rocket it does not have to carry its reaction mass with it.

And a car going twice as fast has four times the Ke. That energy has to come from somewhere. Chemical, electrical whatever. I did misstate a little. If it takes one unit of energy to reach x velocity it will take 3 units to go from there to 2x velocity. Four in total. Again Ke is just energy that has to come from a chemical or electrical source.

Wind resistance and other energy losses are irrelevant to this discussion as they can in principle be made as small as you like. We can assume they are zero for our purposes.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 04/30/2015 09:32 PM
Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.

The latter does not follow from the former.

If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.

No. There are theories in which the past has no beginning (say, cyclic Big Bang/Big Crunch models). In such theories, energy "was always there", there was no point in time when it had to be created.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 04/30/2015 09:35 PM
(snip...)
The thing to do now is to provide extraordinary, compelling evidence. Experiment needs to be redone in a much more clean environment. Eventually, if/when tests in vacuum but on Earth seem to still show the effect, it will need to be redone in space, away from Earth magnetic field, IR radiation etc.

*THEN* the claims will be taken by most scientists very seriously.

From the article, it looks like NASA Eagleworks has replicated the results in a vacuum in the lab:

I know. I did read the article. However, on Earth, vacuum chambers by necessity, are small. It's hard to be sure that some unforeseen electromagnetic interaction still managed to spoil the experiment. This experiment is not yet convincing enough to support the extraordinary claim made.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 04/30/2015 09:37 PM
What I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?

Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.

This part is simple newtonian mechanics. Work = force * distance. So outputPower = Work / unit time = force * distance/unit time = force * velocity.

For the EM drive, the article implies a linear relation between thrust and input power independent of the velocity: thrust = efficiency*inputPower, so we have we have outputPower = inputPower*efficiency*velocity.

So for velocity > 1/efficiency, we get outputPower > inputPower. If this threshold velocity is a few hundred m/s as implied by the numbers given in the article, you can easily stick the EM-drive on a flywheel with a tip velocity higher than 1/efficiency, and feed more than enough energy into the rotation of the flywheel to power the drive if you connect a generator to the flywheel.

Ergo, if you are proposing a mission to Saturn or alpha centauri as in the article, implying that you have a black box constant acceleration drive, you don't need any nuclear reactor to power the drive. You can just use the same kind of drive that is used for propulsion for power generation.

The reason why it doesn't lead to energy nonconservation for rockets is that you'd have to accelerate the propellant to the tip velocity of the flywheel first. But you don't have that problem with a drive that requires no propellant. Although even in that case, it is still a common way to turn heat and pressure into mechanical energy(see reaction turbines).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: A_M_Swallow on 04/30/2015 09:52 PM
From the article the Chinese test "... higher input power (2.5kW) and tested thrust (720mN) levels of an EM Drive."

For equipment massing say 10 kg using F = m a if placed on a mini rail track this should produce an acceleration of
0.72 N / 10 kg = 0.072 m/s2

Using v = u + a t after 10 seconds the vehicle could reach 0.072 m/s2 * 10 s = 0.72 m/s (=1.6 mph)
That is a speed we can see with our eyes.

The power may have to be passed through the rails. Friction and air resistance will produce a slower speed. The weight is a guess.

This experimental setup will allow directional effects and possibly velocity effects to be tested. NASA may have a sufficiently large vacuum test chamber.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 04/30/2015 10:16 PM
Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.

The latter does not follow from the former.

If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.

Conservation of energy is not a fundamental law of the universe. The more fundamental relation is Noether's theorem (http://en.wikipedia.org/wiki/Noether%27s_theorem), which with very general assumptions tells you exactly when and why quantities like energy and momentum are conserved, and when they are useful quantities to define. Specifically, they are conserved because of symmetries.

In particular, energy is not conserved on long time scales in an expanding universe. Light does lose energy to cosmological redshift, for example. But energy and momentum certainly is conserved locally by both general relativity, the standard model, and by pretty much every form of quantum gravity proposal such as string theory, since those are all described by Lagrangians and thus obey Noether's theorem.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 04/30/2015 10:36 PM
Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.

The latter does not follow from the former.

If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.

No. There are theories in which the past has no beginning (say, cyclic Big Bang/Big Crunch models). In such theories, energy "was always there", there was no point in time when it had to be created.

What value is a theory that can never be tested? At best, it's a hypothesis. Sounds an awful lot like religion to me.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Stormbringer on 04/30/2015 10:45 PM
Those cosmologies are testable though. measurements of expansion, total mass, the cosmic  background radiation and so forth have shot them down in the past. But recent questions thrown onto the expansion rate have possibly opened them up again.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 04/30/2015 11:45 PM
Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.

The latter does not follow from the former.

If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.

No. There are theories in which the past has no beginning (say, cyclic Big Bang/Big Crunch models). In such theories, energy "was always there", there was no point in time when it had to be created.

What value is a theory that can never be tested? At best, it's a hypothesis. Sounds an awful lot like religion to me.

You seem to be trying to derail my argument by switching the subject. I hope, unwillingly.

My point is not that cyclic Universe theory is a correct description of Universe.

My point is, existence of energy does not prove its nonconservation: there are logically consistent theories which have nonzero energy but have no point in time where it jumped from zero to nonzero.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/01/2015 12:14 AM
When you have eliminated the impossible, whatever remains, however improbable, must be the truth...
http://en.wikipedia.org/wiki/Bayesian_statistics

You're still much more likely to have fooled yourself than to have found something that is impossible by the known and most well-accepted laws of physics.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: FutureStormtrooper on 05/01/2015 12:32 AM
There are people who believe this is an incredibly exciting, civilization-changing breakthrough, and there are people who believe that it's all pseudo-scientific bunk. But in the interim, both opinions mean far less than the fact that regardless of this spirited, generally well-meaning debate, there are people who are continuing to do these experiments, and that data is being generated, and that sooner or later we will know the truth of the matter once and for all.

I encourage everybody to keep that in the forefront of their mind while reading all threads related to this research.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Prunesquallor on 05/01/2015 01:27 AM
Is the trip time to alpha centauri based on the space drive, or based on the power source?

The Joosten/White IEEE paper shows that constant spacecraft acceleration of around 0.001 g should be possible with Q-Thruster performance of 0.4 N/kWe and reasonable power plant and thruster masses.  The interstellar trip times merely reflect that constant acceleration.  Those computations are quite straightforward, as special relativity as opposed to general relativity can be used, even for the decelerated case.

It ignores the "paradox velocity".
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/01/2015 03:05 AM
Is the trip time to alpha centauri based on the space drive, or based on the power source?

The Joosten/White IEEE paper shows that constant spacecraft acceleration of around 0.001 g should be possible with Q-Thruster performance of 0.4 N/kWe and reasonable power plant and thruster masses.  The interstellar trip times merely reflect that constant acceleration.  Those computations are quite straightforward, as special relativity as opposed to general relativity can be used, even for the decelerated case.

It ignores the "paradox velocity".
Of course, your kinetic energy would be ridiculously high, thousands of times greater than the energy you put into the drive.

For .4N/kW and 40kg/kW specific power for a 1kW craft (weighing 40kg) just to make things easy:

(Kinetic Energy)/(Energy input)=
(.5*40kg*(92years*.4N/kW/(40kg/kW))^2)/(1kW*92years)
=
5806.5

Make no mistake, this is also a method to gain free energy.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robert Thompson on 05/01/2015 03:11 AM
imho I never read the EM drive / Star Trek threads. (I promise myself) I'll truncate my reading of EM stuff here.

 :-\ Do the experiment in heavily shielded containment. In vacuum. Suspended vertically by strong supple inelastic wire from a motion-isolated framework. Covered in temperature and vibration sensors. Motions measured to the nanometer by laser. For thousands of hours. In multiple orientations. Thoroughly probe the parameter space of earth rotation and revolution (first order). Latitude, longitude, altitude, pressure, temperature, humidity, local and global magnetic field, local seismic conditions, tidal/quadrupole orientations of sun, moon, Jupiter. (Second order) What were the galactic/cosmological position and momentum space of every experiment performed so far? Any commonalities from a galactic/cosmological framework.

Synanpses are cheap, digital text is cheap, broad constituencies of imaginations fired by evocative riddles are cheap - that's all a net gain. It also reflects well that a technical problem can be intensively crowd sourced, cheaply. A utility or discovery or success will be located more quickly by crowd source. A futility or lesson or failure will be located more quickly by crowd source. In either case, Mr Spock would (I wager) say NSF is "one" logical place to piranha-ize or sigma clip radical claims, pertaining to space flight, involving NASA employees, that have at least the basis of hardware and data. (Cosmoquest has an advanced topics thunderdome, for another.)  :) /imho
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/01/2015 03:16 AM
Yeah... I'm not getting how this does not violate conservation of momentum and energy. For example if this works you should be able to construct a perpetual motion free energy machine. If constant electrical power produces constant acceleration you have a problem since kinetic energy increases with the square of velocity. You will quickly reach a point where your kinetic energy vastly exceeds the electrical energy input.

Sorry, I smell the stench of cold fusion.
Much worse than cold fusion, IMHO. At least with cold fusion, you're still conserving momentum and energy.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 04:01 AM
There are people who believe this is an incredibly exciting, civilization-changing breakthrough, and there are people who believe that it's all pseudo-scientific bunk. But in the interim, both opinions mean far less than the fact that regardless of this spirited, generally well-meaning debate, there are people who are continuing to do these experiments, and that data is being generated, and that sooner or later we will know the truth of the matter once and for all.

I encourage everybody to keep that in the forefront of their mind while reading all threads related to this research.

The thing to keep at the forefront of your mind is that decades after the first claim of cold fusion there are people still "generating data" and "doing experiments".  It seems like every few years there is a new wave of results. Tech dirt was hyping the latest just last year I think. Every few years Rossi produces a new E-cat that he shops around. Decades from now people will still be debating the EM-drive along with the E-cat. Desire produces suspension of disbelief. That suspension hides the monstrous improbability of the claims. You really are the easiest person for you to fool.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: FutureStormtrooper on 05/01/2015 04:16 AM
The thing to keep at the forefront of your mind is that decades after the first claim of cold fusion there are people still "generating data" and "doing experiments".  It seems like every few years there is a new wave of results. Tech dirt was hyping the latest just last year I think. Every few years Rossi produces a new E-cat that he shops around. Decades from now people will still be debating the EM-drive along with the E-cat. Desire produces suspension of disbelief. That suspension hides the monstrous improbability of the claims. You really are the easiest person for you to fool.

Paul March has been very forthcoming on NSF with experimental setup and data, allowing other experts to cross-check both and suggest possible sources of error. Other groups and individuals have been setting up similar experiments to further the body of data available. This isn't some conspiracy where one individual or small group has a financial incentive to fool the world. Either usable thrust is being generated, or it isn't; one way or another we will know in time.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sanman on 05/01/2015 04:21 AM
http://angryflower.com/experi.html

(http://angryflower.com/experi.gif) (http://angryflower.com/experi.html)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 05/01/2015 06:17 AM
The beauty of reality is that it doesn't give a damn about personal opinions. Accepted physics was derived from observations, hypotheses, real-world experimentation and falsification attempts. I recommend letting the Eagleworks team do what they do, collect experimental data and compare them to their predictions. When there comes a point that there seems to be conclusive evidence, I recommend Eagleworks to compile a detailed HOWTO replicate those setups for just about anybody on the planet to repeat the experiment(s). Prolonging the current non-expedient bickering about whether or not this adheres to 'known' physics is truly pointless. Multiple experiments already showed that something happens.

The right thing to do is to follow the data. Personal opinions don't mean anything.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/01/2015 06:26 AM

The thing to keep at the forefront of your mind is that decades after the first claim of cold fusion there are people still "generating data" and "doing experiments".  It seems like every few years there is a new wave of results. Tech dirt was hyping the latest just last year I think. Every few years Rossi produces a new E-cat that he shops around. Decades from now people will still be debating the EM-drive along with the E-cat. Desire produces suspension of disbelief. That suspension hides the monstrous improbability of the claims. You really are the easiest person for you to fool.

Paul March has been very forthcoming on NSF with experimental setup and data, allowing other experts to cross-check both and suggest possible sources of error. Other groups and individuals have been setting up similar experiments to further the body of data available. This isn't some conspiracy where one individual or small group has a financial incentive to fool the world. Either usable thrust is being generated, or it isn't; one way or another we will know in time.

Precisely. It's not like these experiments have been hidden away from the public view.

As to the conservation of momentum question the number of times that gets asked and answered suggests that a FAQ is needed.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 05/01/2015 06:37 AM
Of course, your kinetic energy would be ridiculously high, thousands of times greater than the energy you put into the drive.

For .4N/kW and 40kg/kW specific power for a 1kW craft (weighing 40kg) just to make things easy:

(Kinetic Energy)/(Energy input)=
(.5*40kg*(92years*.4N/kW/(40kg/kW))^2)/(1kW*92years)
=
5806.5

Make no mistake, this is also a method to gain free energy.
Another useful meme is to beware of people who have simple answers to complex questions.

If Dr White's team is right this thruster is more akin to a propeller or the air breathing nuclear ramjet of project PLUTO, and the "reaction mass" are the virtual particles being preferentially accelerated by the system.

An interesting (but off topic) question would be does a virtual particle cease to exist entirely IE it's whole life is the single existence it's there for, or does it pop up "elsewhere," and is that "elsewhere" this universe, or another universe?

But let me ask you a simpler question.

Do you believe there is something there or IYHO it's all a set of experimental artifacts that have simply not been analyzed out thoroughly enough?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sanman on 05/01/2015 06:46 AM
An interesting (but off topic) question would be does a virtual particle cease to exist entirely IE it's whole life is the single existence it's there for, or does it pop up "elsewhere," and is that "elsewhere" this universe, or another universe?

LOL, maybe the EM drive allows you to propel objects in another universe   ;D
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 07:01 AM
The thing to keep at the forefront of your mind is that decades after the first claim of cold fusion there are people still "generating data" and "doing experiments".  It seems like every few years there is a new wave of results. Tech dirt was hyping the latest just last year I think. Every few years Rossi produces a new E-cat that he shops around. Decades from now people will still be debating the EM-drive along with the E-cat. Desire produces suspension of disbelief. That suspension hides the monstrous improbability of the claims. You really are the easiest person for you to fool.

Paul March has been very forthcoming on NSF with experimental setup and data, allowing other experts to cross-check both and suggest possible sources of error. Other groups and individuals have been setting up similar experiments to further the body of data available. This isn't some conspiracy where one individual or small group has a financial incentive to fool the world. Either usable thrust is being generated, or it isn't; one way or another we will know in time.

And March of next year the debate will still be going on. And the march after. This is so exactly like the early days of Pons  and Fleischmann. Either excess heat is being generated, or it isn't; one way or another we will know in time. Yet 26 years later they are still having conferences.

It isn't about conspiracy or con men. It is about self deception and the desire to believe.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 05/01/2015 07:02 AM
An interesting (but off topic) question would be does a virtual particle cease to exist entirely IE it's whole life is the single existence it's there for, or does it pop up "elsewhere," and is that "elsewhere" this universe, or another universe?

LOL, maybe the EM drive allows you to propel objects in another universe   ;D

Yeah.. and maybe matter is actually an opening in higher-dimensional space that sucks virtual particle pairs into micro-wormholes (=gravity) and randomly spews them out again elsewhere, which we can then observe as an expansion of space. Riiight.. now back to data collection.
;)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 07:23 AM

The thing to keep at the forefront of your mind is that decades after the first claim of cold fusion there are people still "generating data" and "doing experiments".  It seems like every few years there is a new wave of results. Tech dirt was hyping the latest just last year I think. Every few years Rossi produces a new E-cat that he shops around. Decades from now people will still be debating the EM-drive along with the E-cat. Desire produces suspension of disbelief. That suspension hides the monstrous improbability of the claims. You really are the easiest person for you to fool.

Paul March has been very forthcoming on NSF with experimental setup and data, allowing other experts to cross-check both and suggest possible sources of error. Other groups and individuals have been setting up similar experiments to further the body of data available. This isn't some conspiracy where one individual or small group has a financial incentive to fool the world. Either usable thrust is being generated, or it isn't; one way or another we will know in time.

Precisely. It's not like these experiments have been hidden away from the public view.

As to the conservation of momentum question the number of times that gets asked and answered suggests that a FAQ is needed.

A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it? 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 08:02 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
According to Shawyer, when the EMDrive accelerates, the resonate cavity loses energy to the accelerating mass and it's Q drops, which reduces the generated force. To maintain constant force, the primary energy source needs to restore the lost resonate cavity energy. End result is COE is conserved.

When Shawyer builds a demonstrator EMDrive it is serious hardware: http://emdrive.com/demonstratorengine.html

No microNewtons here:

Quote
The engine was built with a design factor of 0.844 and has a measured Q of 45,000 for an overall diameter of 280 mm. The microwave source is a water cooled magnetron with a variable output power up to a maximum of 1.2 kW.

To obtain the predicted thrust the engine must maintain stable resonance at this high Q value. Major design challenges have included thermal compensation, tuning control and source matching.

The engine was tested in a large static test rig employing a calibrated composite balance to measure thrust in 3 directions, up, down and horizontal. A total of 134 test runs were carried out over the full performance envelope, with a maximum specific thrust of 214mN/kW being measured.

You could feel the 22 grams of thrust with your hand.

My question is why didn't EagleWorks test this unit as it appears to be almost fully self contained and travel ready?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 08:29 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
According to Shawyer, when the EMDrive accelerates, the resonate cavity loses energy to the accelerating mass and it's Q drops, which reduces the generated force. To maintain constant force, the primary energy source needs to restore the lost resonate cavity energy. End result is COE is conserved.

Yeah, see that isn't very clear. And at best it does not solve your problem. Worse, I can't even tell if you understand the problem.

Ok lets say you have a spaceship powered by the Em-drive. Say you are motionless in space and turn it on and a thousand watts of power gives you a tenth of a gravity of acceleration. You accelerate up to a mile per second. Ok now how many watts of power does it take to continue accelerating at a tenth of a gravity? The same thousand? A million watts? more?

If it is the same thousand watts then you are violating conservation of energy. Do you understand this?

If you need more power at higher velocity then you can tell your absolute velocity by how much energy your engine needs to accelerate. This effectively creates a preferred frame of reference in violation of just about all modern physics. Do you understand this?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 08:38 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
According to Shawyer, when the EMDrive accelerates, the resonate cavity loses energy to the accelerating mass and it's Q drops, which reduces the generated force. To maintain constant force, the primary energy source needs to restore the lost resonate cavity energy. End result is COE is conserved.

Yeah, see that isn't very clear. And at best it does not solve your problem. Worse, I can't even tell if you understand the problem.

Ok lets say you have a spaceship powered by the Em-drive. Say you are motionless in space and turn it on and a thousand watts of power gives you a tenth of a gravity of acceleration. You accelerate up to a mile per second. Ok now how many watts of power does it take to continue accelerating at a tenth of a gravity? The same thousand? A million watts? more?

If it is the same thousand watts then you are violating conservation of energy. Do you understand this?

If you need more power at higher velocity then you can tell your absolute velocity by how much energy your engine needs to accelerate. This effectively creates a preferred frame of reference in violation of just about all modern physics. Do you understand this?
EMDrive creates force from microwave energy input. To do work, accelerate the ship's mass, the EMDrive acts like a conversion conduit, converting source electrical energy into microwave energy, stored in the resonate cavity, into kinetic energy gain as the ship accelerates.

COE is conserved.

At one time it was not known an electrical current, flowing in a coil, could produce a magnetic field, that produced force on nearby ferrous objects. However for the magnetic field to do work on the ferrous objects / move them, that energy came from the primary electrical energy source and not from the coil's magnetic force field.

Different dog, same leg action.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 09:11 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
According to Shawyer, when the EMDrive accelerates, the resonate cavity loses energy to the accelerating mass and it's Q drops, which reduces the generated force. To maintain constant force, the primary energy source needs to restore the lost resonate cavity energy. End result is COE is conserved.

Yeah, see that isn't very clear. And at best it does not solve your problem. Worse, I can't even tell if you understand the problem.

Ok lets say you have a spaceship powered by the Em-drive. Say you are motionless in space and turn it on and a thousand watts of power gives you a tenth of a gravity of acceleration. You accelerate up to a mile per second. Ok now how many watts of power does it take to continue accelerating at a tenth of a gravity? The same thousand? A million watts? more?

If it is the same thousand watts then you are violating conservation of energy. Do you understand this?

If you need more power at higher velocity then you can tell your absolute velocity by how much energy your engine needs to accelerate. This effectively creates a preferred frame of reference in violation of just about all modern physics. Do you understand this?
EMDrive creates force from microwave energy input. To do work, accelerate the ship's mass, the EMDrive acts like a conversion conduit, converting source electrical energy into microwave energy, stored in the resonate cavity, into kinetic energy gain as the ship accelerates.

COE is conserved.

At one time it was not known an electrical current, flowing in a coil, could produce a magnetic field, that produced force on nearby ferrous objects. However for the magnetic field to do work on the ferrous objects / move them, that energy came from the primary electrical energy source and not from the coil's magnetic force field.

Different dog, same leg action.

Yeah, even less clear. your failure to answer my question leaves me no choice but to assume that you don't understand the problem. You simply assert COE and never even mention the problem with a preferred frame of reference. If you will not answer my question I don't know how to proceed but I'm pretty sure A FAQ isn't going to help. But feel free to go tell your friends that the COE question has been asked and answered countless times and I'll tell people how pointless it is to play chess with a pigeon.

Or you can try to understand and answer the questions I asked.


 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 09:24 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
Force is not Work.

Shawyer clearly states when the cavity moves, it's Q drops, which means it's load impedance as seen by the microwave generator on board the ship drops. This causes the microwave generator to deliver more energy into the resonate cavity to restore the lost cavity energy (due to lower cavity Q due to cavity energy converted into Kinetic energy by the EMDrive) from the electrical source

No where does Shawyer claim the EMDrive will constantly accelerate, as you assume, without needing more microwave energy to be inputted into the resonate cavity.

If you would like to review what Shawyer has said, please read all the papers and links here: www.emdrive.com

See his theory paper and equations for power needed to support EMDrive acceleration:
http://www.emdrive.com/theorypaper9-4.pdf
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sanman on 05/01/2015 09:32 AM
Someone said that the reference frame of the wave inside the resonant cavity becomes a preferred frame of reference, since the wave is what's said to be losing energy. I don't know enough to say if that's plausible or outright nonsense.


Here's one of the very first refutations published against Shawyer's EMdrive - it's by someone named John Costella:

http://johncostella.webs.com/shawyerfraud.pdf

Costella is apparently a PhD in electrodynamics, and his website shows an interest in investigating diverse things, including JFK's assassination.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RotoSequence on 05/01/2015 09:42 AM
Here's one of the very first refutations published against Shawyer's EMdrive - it's by someone named John Costella:

http://johncostella.webs.com/shawyerfraud.pdf

Costella is apparently a PhD in electrodynamics, and his website shows an interest in investigating diverse things, including JFK's assassination.

I'm not really okay with any attempt to discredit someone's analysis/critique of EM drive by invoking what they have to say about something else. EM Drive needs to be able to stand on its own two feet, and if the critics are right, they're right, and if they're wrong, they're wrong. What they have to say about other things aren't relevant.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Stormbringer on 05/01/2015 09:46 AM


A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?

I heard a sacred cow lowing in the meadow. I must slay it.

The universe does have preferred directions. Time is an obvious example. But the data from the cosmic background radiation and studies of the large scale structure of the universe have issues that are best tentative explained (at least for now) by it having preferred directions WRT  some of it's other properties.
The rotations of galaxies has a preferred alignment. Dark Flow also seems to indicate a preferred direction as well. The universe itself appears to be spinning.

Die cow, die.   ;D
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 09:46 AM
Someone said that the reference frame of the wave inside the resonant cavity becomes a preferred frame of reference, since the wave is what's said to be losing energy. I don't know enough to say if that's plausible or outright nonsense.


Here's one of the very first refutations published against Shawyer's EMdrive - it's by someone named John Costella:

http://johncostella.webs.com/shawyerfraud.pdf

Costella is apparently a PhD in electrodynamics, and his website shows an interest in investigating diverse things, including JFK's assassination.
Calling the EMDrive a fraud is walking the plank, especially as multiple labs, in multiple countries, testing various build variations, all found significant thrust.

Still don't understand why EagleWorks didn't test Shawyers 2009 demo device? 214mN/kW would be SO FAR above noise/error as to totally remove any doubt. But instead they built their variation that produced microNewton thrust at mosquito levels and introduced room for doubters to live another day.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 09:51 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
Force is not Work.

Shawyer clearly states when the cavity moves, it's Q drops, which means it's load impedance as seen by the microwave generator on board the ship drops. This causes the microwave generator to deliver more energy into the resonate cavity to restore the lost cavity energy (due to lower cavity Q due to cavity energy converted into Kinetic energy by the EMDrive) from the electrical source

No where does Shawyer claim the EMDrive will constantly accelerate, as you assume, without needing more microwave energy to be inputted into the resonate cavity.

If you would like to review what Shawyer has said, please read all the papers and links here: www.emdrive.com

See his theory paper and equations for power needed to support EMDrive acceleration:
http://www.emdrive.com/theorypaper9-4.pdf

I never said force is work. Force times distance is work but I have no idea why that is relevant here.

I do not assume that the thing accelerates constantly. I asked you if it accelerates constantly. You see if it accelerates constantly you have one problem and if it does not you have a different problem.

Ok you are going with it does not accelerate constantly although getting that out of you was like pulling teeth. Do you understand how this violates relativity and just about all of modern physics? It would almost be simpler to violate COE.

For example it creates the problem that the power needed by the drive would change massively depending on the time of year. Do you understand why?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 10:04 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
Force is not Work.

Shawyer clearly states when the cavity moves, it's Q drops, which means it's load impedance as seen by the microwave generator on board the ship drops. This causes the microwave generator to deliver more energy into the resonate cavity to restore the lost cavity energy (due to lower cavity Q due to cavity energy converted into Kinetic energy by the EMDrive) from the electrical source

No where does Shawyer claim the EMDrive will constantly accelerate, as you assume, without needing more microwave energy to be inputted into the resonate cavity.

If you would like to review what Shawyer has said, please read all the papers and links here: www.emdrive.com

See his theory paper and equations for power needed to support EMDrive acceleration:
http://www.emdrive.com/theorypaper9-4.pdf

I never said force is work. Force times distance is work but I have no idea why that is relevant here.

I do not assume that the thing accelerates constantly. I asked you if it accelerates constantly. You see if it accelerates constantly you have one problem and if it does not you have a different problem.

Ok you are going with it does not accelerate constantly although getting that out of you was like pulling teeth. Do you understand how this violates relativity and just about all of modern physics? It would almost be simpler to violate COE.

For example it creates the problem that the power needed by the drive would change massively depending on the time of year. Do you understand why?
I'm just a hack engineer who designs, builds and commissions stuff. Mostly guided by a well educated gut, from making lots of stupid mistakes.

I see the "Laws of Physics" as a set of assumptions, which seem to closely fit and predict what we have so far observed. That the EMDrive works is beyond doubt. That it seems to violate the LAWS as you understand them is, with respect, your issue. Shawyer has no issue with his understanding of the LAWS nor do I.

As for me, I think I can design one into a ship and make it work. What happens inside the resonate cavity and why is above my pay grade. What it works, is for me beyond doubt. That how it reacts to power input and kinetic energy output is understood enough to use it to move stuff.

BTW my frame of reference is my gut, which is now asking me for a nice glass of Red.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 10:23 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
Force is not Work.

Shawyer clearly states when the cavity moves, it's Q drops, which means it's load impedance as seen by the microwave generator on board the ship drops. This causes the microwave generator to deliver more energy into the resonate cavity to restore the lost cavity energy (due to lower cavity Q due to cavity energy converted into Kinetic energy by the EMDrive) from the electrical source

No where does Shawyer claim the EMDrive will constantly accelerate, as you assume, without needing more microwave energy to be inputted into the resonate cavity.

If you would like to review what Shawyer has said, please read all the papers and links here: www.emdrive.com

See his theory paper and equations for power needed to support EMDrive acceleration:
http://www.emdrive.com/theorypaper9-4.pdf

I never said force is work. Force times distance is work but I have no idea why that is relevant here.

I do not assume that the thing accelerates constantly. I asked you if it accelerates constantly. You see if it accelerates constantly you have one problem and if it does not you have a different problem.

Ok you are going with it does not accelerate constantly although getting that out of you was like pulling teeth. Do you understand how this violates relativity and just about all of modern physics? It would almost be simpler to violate COE.

For example it creates the problem that the power needed by the drive would change massively depending on the time of year. Do you understand why?
I'm just a hack engineer who designs, builds and commissions stuff. Mostly guided by a well educated gut, from making lots of stupid mistakes.

I see the "Laws of Physics" as a set of assumptions, which seem to closely fit and predict what we have so far observed. That the EMDrive works is beyond doubt. That it seems to violate the LAWS as you understand them is your issue. Shawyer has no issue with his understanding of the LAWS nor do I.

As for me, I think I can design one into a ship and make it work. What happens inside the resonate cavity and why is above my pay grade. What it works, is for me beyond doubt. That how it reacts to power input and kinetic energy output is understood enough to use it to move stuff.

BTW my frame of reference is my gut, which is now asking me for a nice glass of Red.

Yes well as a "hack engineer" you may want to figure out why your ship works fine in December but fails to produce significant thrust in June. To do that you will need to understand frames of reference. But if you take the time to do that you may rethink your confidence in the drive.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 10:39 AM
Yes well as a "hack engineer" you may want to figure out why your ship works fine in December but fails to produce significant thrust in June. To do that you will need to understand frames of reference. But if you take the time to do that you may rethink your confidence in the drive.
Your reference link?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Layllah on 05/01/2015 11:29 AM
So Nasa tested the EM drive and it worked according to several news generators? Doesn't that defy Newtons laws of motion?Don't get me wrong this is wonderful news and the fact that some age old set in stone laws now have question marks could change the way we think about space travel. I mean we've been looking for the elusive "Gravaton" to no avail the fact EM drive works indicates different rules apply. I hope the results generate more experiments! Great work!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 05/01/2015 11:42 AM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
Force is not Work.

Shawyer clearly states when the cavity moves, it's Q drops, which means it's load impedance as seen by the microwave generator on board the ship drops. This causes the microwave generator to deliver more energy into the resonate cavity to restore the lost cavity energy (due to lower cavity Q due to cavity energy converted into Kinetic energy by the EMDrive) from the electrical source

No where does Shawyer claim the EMDrive will constantly accelerate, as you assume, without needing more microwave energy to be inputted into the resonate cavity.

If you would like to review what Shawyer has said, please read all the papers and links here: www.emdrive.com

See his theory paper and equations for power needed to support EMDrive acceleration:
http://www.emdrive.com/theorypaper9-4.pdf

So how exactly does that apply to the case where it is traveling at a constant velocity and fighting friction? By the principle of relativity, there is no difference between the case of static thrust and the case of static velocity. So you can still use this to create more work than you put into it.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 05/01/2015 12:22 PM
Commander Chris Hadfield just tweeted it to his 1.3 million followers.  :o
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 12:36 PM
Yes well as a "hack engineer" you may want to figure out why your ship works fine in December but fails to produce significant thrust in June. To do that you will need to understand frames of reference. But if you take the time to do that you may rethink your confidence in the drive.
Your reference link?

What link? If the thrust is frame dependent then your ship will be in very different inertial frames in December and June and your drive will perform very differently depending on the time of year. That is a logical consequence of your choice to say that it does not accelerate constantly with constant energy input.

You don't even understand the nature of the problem I'm trying to explain.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 12:44 PM
So how exactly does that apply to the case where it is traveling at a constant velocity and fighting friction? By the principle of relativity, there is no difference between the case of static thrust and the case of static velocity. So you can still use this to create more work than you put into it.
If the ship is travelling at constant velocity, there is no acceleration occurring, no thrust being produced by the EMDrive, so the EMDrive is switched OFF.

When the EMDrive generates thrust, unless restrained from moving, it will cause the mass of what ever it is attached to move / accelerate, dropping resonate cavity Q, causing the EMDrive microwave load impedance to drop, causing the microwave generator to transfer more energy into the resonate cavity to restore the loss of cavity energy converted to kinetic, causing the microwave generator to draw more power from the primary electrical energy source.

COE is conserved.

All EMDrive does is to convert electrical energy into, if the EMDrive moves, kinetic energy. No OU. No free energy.

Ok a new / strange energy conversion technique but so was the 1st coil generating a magnetic field, so was the 1st motor, converting electrical energy into a magnetic field, into torque.

For the coil, the motor and the EMDrive, COE was conserved.

Interesting history of the development of electrical energy being converted into torque:
http://en.wikipedia.org/wiki/Timeline_of_the_electric_motor

Soon to be added: History of the development of electrical energy being converted into kinetic energy:
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 12:48 PM
What link? If the thrust is frame dependent then your ship will be in very different inertial frames in December and June and your drive will perform very differently depending on the time of year. That is a logical consequence of your choice to say that it does not accelerate constantly with constant energy input.

You don't even understand the nature of the problem I'm trying to explain.
When did I say the EMDrive will not constantly accelerate if supplied with a constant energy input to the magnetron, maintaining a constant level of microwave energy in the resonant cavity as cavity microwave impedance drops, due to acceleration, from cavity stored energy conversion into kinetic?

It converts electrical energy into kinetic energy, if the EMDrive is allowed to move.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Ben the Space Brit on 05/01/2015 01:10 PM
That last illustration, with the double ring "Enterprise", shows a bluish exhaust or ionization trail.  Maybe I misunderstood something, but I thought the EM drive did not have an exhaust.  Artistic license?  Pre-existing picture?

I don't know the provenance of this particular picture but it's based on a much, much older work. The 'S.S. Enterprise' was production art that originally came from the Star Trek art studio in the late 1970s. The original oil painting was used in a licensed book called "Spaceflight Chronology (http://en.memory-alpha.org/wiki/Star_Trek_Spaceflight_Chronology)" (1979) in which it was described as a pre-Federation star liner. Prints and models based on the original work have also been used as set dressings in several of the Next Generation-era shows.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 05/01/2015 01:23 PM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
Force is not Work.

Shawyer clearly states when the cavity moves, it's Q drops, which means it's load impedance as seen by the microwave generator on board the ship drops. This causes the microwave generator to deliver more energy into the resonate cavity to restore the lost cavity energy (due to lower cavity Q due to cavity energy converted into Kinetic energy by the EMDrive) from the electrical source

No where does Shawyer claim the EMDrive will constantly accelerate, as you assume, without needing more microwave energy to be inputted into the resonate cavity.

If you would like to review what Shawyer has said, please read all the papers and links here: www.emdrive.com

See his theory paper and equations for power needed to support EMDrive acceleration:
http://www.emdrive.com/theorypaper9-4.pdf

I never said force is work. Force times distance is work but I have no idea why that is relevant here.

I do not assume that the thing accelerates constantly. I asked you if it accelerates constantly. You see if it accelerates constantly you have one problem and if it does not you have a different problem.

Ok you are going with it does not accelerate constantly although getting that out of you was like pulling teeth. Do you understand how this violates relativity and just about all of modern physics? It would almost be simpler to violate COE.

For example it creates the problem that the power needed by the drive would change massively depending on the time of year. Do you understand why?

Ok,

     Let me see if I can break this down to its simplest elements that laymen can understand.

     One, in order for it to the drive to work, energy has to be expended to create a propulsive force. (ie. Thrust)

     Two, "for every action, there has to be an equal and opposite reaction".  Basic Newtonian Physics, not a hundred percent accurate, but close enough.

     Three, electricity is being used to create Radio Frequencies within "The Device".

     Four, somehow, these "Radio Waves" are imparting their energy to "The Device" in such a way as to produce kinetic force in one particular direction.  (ie. Thrust)

     Five, the "Radio Waves" seem to be being expended in a direction opposite of the direction of thrust, if I understand the diagrams I have seen so far.

     Six, since energy is matter in a more coherent form than lasers or plasma, mass is being expended in a direction opposite the direction of motion.

     Seven, again, unless I am misunderstanding these diagrams, heat is being generated as part of this conversion of energy to thrust.

     Eight, in order to continue to generate thrust, more energy must be expended in order to generate RF, which is converted by "The Device" into heat and thrust.

     Nine, so, in order to generate thrust; mass, in the form of energy, is being expended and expelled in a direction of motion opposite of the direction of thrust, energy is being used to impart this motion. Heat is being generated as a byproduct of this process, and an amount of energy, similar to or larger than the normal amount of energy needed to break free of inertia and produce thrust, is being used, and if no additional energy is applied to the device, it stops generating thrust.  I think that pretty much sums up what we know so far.

     So, Ten, it appears as though this device is a more efficient form of thrust convertion device than are chemical, plasma or nuclear rockets, which require mass be expended in the form of propellent, in order to produce thrust.  It appears that mass, in the form of electrons, in this case, are being expended in order to impart thrust, but doing so in a much more energy efficent manner.

     Finally, if "The Device" is indeed producing thrust in this manner, and we don't quite have a grasp on HOW it's doing what it does, (I'm pretty sure there is some very simple explaination that everybody is overlooking, as these things usually wind up being) I'm not really quite sure WHAT particular law of physics that it is violating. none of the laws of motion or thermodynamics appear to be violated on the face of it. So, if it is indeed producing thrust, as all the tests so far seem to indicate, now all we need to do is figure out HOW it's doing it!

Oh! I also forgot to mention that the amount of theurst varies according to both the input of energy and the frequency of the RF generated.  (From what I think I understand, the higher the frequency, the more thrust is directly cvreated by "The Device")  Again, no violation of thermodynamics or Newtonian physics.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Ben the Space Brit on 05/01/2015 01:29 PM
Jason, thanks for the explanation that's simple enough for a guy who flunked A-level physics to understand!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 01:36 PM
What link? If the thrust is frame dependent then your ship will be in very different inertial frames in December and June and your drive will perform very differently depending on the time of year. That is a logical consequence of your choice to say that it does not accelerate constantly with constant energy input.

You don't even understand the nature of the problem I'm trying to explain.
When did I say the EMDrive will not constantly accelerate if supplied with a constant energy input to the magnetron, maintaining a constant level of microwave energy in the resonant cavity as microwave impedance drops from cavity energy conversion to kinetic?

It converts electrical energy into kinetic energy, if the EMDrive is allowed to move.

That is what I was asking when I asked if it accelerated constantly. I mean constantly with constant power input. If power input is constant then total energy input increases linearly with time producing constant acceleration so velocity increases linearly with time. But kinetic energy increases with the square of velocity and so increases with the square of time.

Power input (electrical energy) is constant while energy output (kinetic energy) is growing much faster and at an ever increasing rate. That violates COE. That is because kinetic energy is proportional to the square of velocity.

If you had an electric car, 100% efficient and no friction losses, and gave it constant power input it would not accelerate constantly. It would start off with good acceleration but that would quickly fall to near zero as its velocity increased. You would need ever higher power inputs in order to just maintain constant acceleration. If your EMdrive works any different then it violates COE.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 01:36 PM
Ok,

     Let me see if I can break this down to its simplest elements that laymen can understand.

     One, in order for it to the drive to work, energy has to be expended to create a propulsive force. (ie. Thrust)

     Two, "for every action, there has to be an equal and opposite reaction".  Basic Newtonian Physics, not a hundred percent accurate, but close enough.

     Three, electricity is being used to create radio Frequencies within "The Device".

     Four, somehow, these "Radio Waves" are imparting their energy to "The Device" in such a way as to produce kinetic force.  (ie. Thrust)

     Five, the "Radio Waves" seem to be being expended in a direction opposite of the direction of thrust, if I understand the diagrams I have seen so far.

     Six, since energy is matter in a more coherent form than lasers or plasma, mass is being expended in a direction opposite the direction of motion.

     Seven, again, unless I am misunderstanding these diagrams, heat is being generated as part of this conversion of energy to thrust.

     Eight, in order to continue to generate thrust, more energy must be expended in order to generate RF, which is converted by "The Device" into heat and thrust.

     Nine, so, in order to generate thrust; mass, in the form of energy, is being expended and expelled in a direction of motion opposite of the direction of thrust, energy is being used to impart this motion. heat is being generated as a byproduct of this process, and an amount of energy, similar to or larger than the normal amount of energy needed to break free of inertia and produce thrust, is being used, and if no additional energy is applied to the device, it stops generating thrust.  I think that pretty much sums up what we know so far.

     So, Ten, it appears as though this device is a more efficient form of thrust convertion device than are chemical, plasma or nuclear rockets, which require mass be expended in the form of propellent, in order to produce thrust.  It appears that mass, in the form of electrons, in this case, are being expended in order to impart thrust, but doing so in a much more energy efficent manner.

     Finally, if "The Device" is indeed producing thrust in this manner, and we don't quite have a grasp on HOW it's doing what it does, (I'm pretty sure there is some very simple explaination that everybody is overlooking, as these things usually wind up being) I'm not really quite sure WHAT particular law of physics that it is violating. non-of the lawsof motion or thermodynamicsa appear to be violated on the face of it. So, if it is indeed producing thrust as all the tests so far seem to indicate, now all we need to do is figure out HOW it's doing it!

Heat is created by eddy currents in the walls of the cavity. They draw energy from the cavity energy, reducing stored cavity energy and cavity Q which is energy input per cycle to energy loss per cycle. This lost cavity energy reduces cavity stored energy and resultant generated thrust. The heat loss is not involved in thrust generation. It actually reduces thrust.

No mass is being expelled.

Please read: http://www.emdrive.com/theorypaper9-4.pdf
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 05/01/2015 01:38 PM
Jason, thanks for the explanation that's simple enough for a guy who flunked A-level physics to understand!

      Hey, I try.  I'm just trying to simplify the concepts enough that everybody can wrap their heads around what is happening.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 05/01/2015 01:40 PM
Ok,

     Let me see if I can break this down to its simplest elements that laymen can understand.

     One, in order for it to the drive to work, energy has to be expended to create a propulsive force. (ie. Thrust)

     Two, "for every action, there has to be an equal and opposite reaction".  Basic Newtonian Physics, not a hundred percent accurate, but close enough.

     Three, electricity is being used to create radio Frequencies within "The Device".

     Four, somehow, these "Radio Waves" are imparting their energy to "The Device" in such a way as to produce kinetic force.  (ie. Thrust)

     Five, the "Radio Waves" seem to be being expended in a direction opposite of the direction of thrust, if I understand the diagrams I have seen so far.

     Six, since energy is matter in a more coherent form than lasers or plasma, mass is being expended in a direction opposite the direction of motion.

     Seven, again, unless I am misunderstanding these diagrams, heat is being generated as part of this conversion of energy to thrust.

     Eight, in order to continue to generate thrust, more energy must be expended in order to generate RF, which is converted by "The Device" into heat and thrust.

     Nine, so, in order to generate thrust; mass, in the form of energy, is being expended and expelled in a direction of motion opposite of the direction of thrust, energy is being used to impart this motion. heat is being generated as a byproduct of this process, and an amount of energy, similar to or larger than the normal amount of energy needed to break free of inertia and produce thrust, is being used, and if no additional energy is applied to the device, it stops generating thrust.  I think that pretty much sums up what we know so far.

     So, Ten, it appears as though this device is a more efficient form of thrust convertion device than are chemical, plasma or nuclear rockets, which require mass be expended in the form of propellent, in order to produce thrust.  It appears that mass, in the form of electrons, in this case, are being expended in order to impart thrust, but doing so in a much more energy efficent manner.

     Finally, if "The Device" is indeed producing thrust in this manner, and we don't quite have a grasp on HOW it's doing what it does, (I'm pretty sure there is some very simple explaination that everybody is overlooking, as these things usually wind up being) I'm not really quite sure WHAT particular law of physics that it is violating. non-of the lawsof motion or thermodynamicsa appear to be violated on the face of it. So, if it is indeed producing thrust as all the tests so far seem to indicate, now all we need to do is figure out HOW it's doing it!
Heat is created by eddy currents in the walls of the cavity. They draw energy from the cavity energy, reducing stored cavity energy and cavity Q which is energy input per cycle to energy loss per cycle. This loss energy reduces cavity stored energy and thrust. The heat loss is not involved in thrust generation. It actually reduces thrust.

No mass is being expelled.

Please read: http://www.emdrive.com/theorypaper9-4.pdf

Simple question; Do electrons have mass?  If not, you are correct, if so, mass is being expended.  Perhaps minute quantities, but it IS being expended.

From Jefferson Labs in Virginia: Electron = 9.1093897*10-31 kg.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 01:43 PM
That is what I was asking when I asked if it accelerated constantly. I mean constantly with constant power input. If power input is constant then total energy input increases linearly with time producing constant acceleration so velocity increases linearly with time. But kinetic energy increases with the square of velocity and so increases with the square of time.

Power input (electrical energy) is constant while energy output (kinetic energy) is growing much faster and at an ever increasing rate. That violates COE. That is because kinetic energy is proportional to the square of velocity.

If you had an electric car, 100% efficient and no friction losses, and gave it constant power input it would not accelerate constantly. It would start off with good acceleration but that would quickly fall to near zero as its velocity increased. You would need ever higher power inputs in order to just maintain constant acceleration. If your EMdrive works any different then it violates COE.
Deep space Ion / Hall thrusters have constant energy input, resultant constant thrust as long as fuel lasts. They accelerate the craft to faster and faster velocities.

EMDrive is no different, has constant energy input, resultant constant thrust, except it doesn't expel mass at a high velocity nor require fuel other than to supply the electricity generators.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 01:52 PM
Simple question; Do electrons have mass?  If not, you are correct, if so, mass is being expended.  Perhaps minute quantities, but it IS being expended.

From Jefferson Labs in Virginia: Electron = 9.1093897*10-31 kg.
Forget me. I'm just the messenger.

Shawyer has been building and testing EMDrives since 2003. In 2009 he had a demo EMDrive available for anyone to test. See attached photo. Did anyone / NASA test? I assume the Chinese did and built their own EMDrive with Shawyer's help.

Please refer to his equations: http://www.emdrive.com/theorypaper9-4.pdf

Nothing is leaving the cavity but eddy current skin heat losses, which REDUCE the thrust. Note Shawyer has gone to superconducting cavity walls to REDUCE heat losses, that reduce cavity Q, which reduce cavity thrust generation.

Think of this as coil DC resistance losses, which reduce AC coil Q and the level of mag field "B" generation.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 05/01/2015 01:57 PM
So how exactly does that apply to the case where it is traveling at a constant velocity and fighting friction? By the principle of relativity, there is no difference between the case of static thrust and the case of static velocity. So you can still use this to create more work than you put into it.
If the ship is travelling at constant velocity, there is no acceleration occurring, no thrust being produced by the EMDrive, so the EMDrive is switched OFF.

When the EMDrive generates thrust, unless restrained from moving, it will cause the mass of what ever it is attached to move / accelerate, dropping resonate cavity Q, causing the EMDrive microwave load impedance to drop, causing the microwave generator to transfer more energy into the resonate cavity to restore the loss of cavity energy converted to kinetic, causing the microwave generator to draw more power from the primary electrical energy source.

COE is conserved.

All EMDrive does is to convert electrical energy into, if the EMDrive moves, kinetic energy. No OU. No free energy.

Ok a new / strange energy conversion technique but so was the 1st coil generating a magnetic field, so was the 1st motor, converting electrical energy into a magnetic field, into torque.

For the coil, the motor and the EMDrive, COE was conserved.

Interesting history of the development of electrical energy being converted into torque:
http://en.wikipedia.org/wiki/Timeline_of_the_electric_motor

Soon to be added: History of the development of electrical energy being converted into kinetic energy:

Sigh. The thrust reported from the EM drive tests is from a static test article. It is not moving. Does that mean the drive is turned off? Of course not.

Now consider the exact same test stand, but on a train moving at a constant speed. The difference here is that since the train is moving in the direction the force is applied, you will get work out of it. If the train's speed is higher than the power to thrust ratio of the drive, the work applied to the train is higher than the power fed into the drive. So you can connect a dynamo to the train's wheels to take out energy that you can feed back into the drive.

For rockets, this is just the Oberth effect. The kinetic energy of the propellant is fed into what remains of the rocket. But in the case where there is no propellant used up, you violate conservation of energy.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 01:58 PM
A FAQ will not change the fact that you are on the horns of a dilemma. Either the thing accelerates constantly and you violate energy and momentum or it does not and you create a preferred frame of reference. Which is it?
Force is not Work.

Shawyer clearly states when the cavity moves, it's Q drops, which means it's load impedance as seen by the microwave generator on board the ship drops. This causes the microwave generator to deliver more energy into the resonate cavity to restore the lost cavity energy (due to lower cavity Q due to cavity energy converted into Kinetic energy by the EMDrive) from the electrical source

No where does Shawyer claim the EMDrive will constantly accelerate, as you assume, without needing more microwave energy to be inputted into the resonate cavity.

If you would like to review what Shawyer has said, please read all the papers and links here: www.emdrive.com

See his theory paper and equations for power needed to support EMDrive acceleration:
http://www.emdrive.com/theorypaper9-4.pdf

I never said force is work. Force times distance is work but I have no idea why that is relevant here.

I do not assume that the thing accelerates constantly. I asked you if it accelerates constantly. You see if it accelerates constantly you have one problem and if it does not you have a different problem.

Ok you are going with it does not accelerate constantly although getting that out of you was like pulling teeth. Do you understand how this violates relativity and just about all of modern physics? It would almost be simpler to violate COE.

For example it creates the problem that the power needed by the drive would change massively depending on the time of year. Do you understand why?

Ok,

     Let me see if I can break this down to its simplest elements that laymen can understand.

     One, in order for it to the drive to work, energy has to be expended to create a propulsive force. (ie. Thrust)

     Two, "for every action, there has to be an equal and opposite reaction".  Basic Newtonian Physics, not a hundred percent accurate, but close enough.

     Three, electricity is being used to create Radio Frequencies within "The Device".

     Four, somehow, these "Radio Waves" are imparting their energy to "The Device" in such a way as to produce kinetic force in one particular direction.  (ie. Thrust)

     Five, the "Radio Waves" seem to be being expended in a direction opposite of the direction of thrust, if I understand the diagrams I have seen so far.

     Six, since energy is matter in a more coherent form than lasers or plasma, mass is being expended in a direction opposite the direction of motion.

     Seven, again, unless I am misunderstanding these diagrams, heat is being generated as part of this conversion of energy to thrust.

     Eight, in order to continue to generate thrust, more energy must be expended in order to generate RF, which is converted by "The Device" into heat and thrust.

     Nine, so, in order to generate thrust; mass, in the form of energy, is being expended and expelled in a direction of motion opposite of the direction of thrust, energy is being used to impart this motion. Heat is being generated as a byproduct of this process, and an amount of energy, similar to or larger than the normal amount of energy needed to break free of inertia and produce thrust, is being used, and if no additional energy is applied to the device, it stops generating thrust.  I think that pretty much sums up what we know so far.

     So, Ten, it appears as though this device is a more efficient form of thrust convertion device than are chemical, plasma or nuclear rockets, which require mass be expended in the form of propellent, in order to produce thrust.  It appears that mass, in the form of electrons, in this case, are being expended in order to impart thrust, but doing so in a much more energy efficent manner.

     Finally, if "The Device" is indeed producing thrust in this manner, and we don't quite have a grasp on HOW it's doing what it does, (I'm pretty sure there is some very simple explaination that everybody is overlooking, as these things usually wind up being) I'm not really quite sure WHAT particular law of physics that it is violating. none of the laws of motion or thermodynamics appear to be violated on the face of it. So, if it is indeed producing thrust, as all the tests so far seem to indicate, now all we need to do is figure out HOW it's doing it!

Oh! I also forgot to mention that the amount of theurst varies according to both the input of energy and the frequency of the RF generated.  (From what I think I understand, the higher the frequency, the more thrust is directly cvreated by "The Device")  Again, no violation of thermodynamics or Newtonian physics.

If the thing is getting thrust by ejecting mass then it is just a rocket. But it cannot be getting thrust by ejecting electrons or photons as that would be easily noticed and would need a great deal of energy to do. It also has the problem of any rocket in that it quickly runs out of whatever it is using as reaction mass. The best it can do is eject photons and to get the thrust reported you would need a huge power input and you would probably burn down the lab.

But that is a change of subject. If the thing gets constant acceleration with constant power input then it violates COE because Ke goes with the square of velocity. And if the thing does not accelerate constantly with constant power input it violates relativity.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 02:02 PM
Ok,

     Let me see if I can break this down to its simplest elements that laymen can understand.

     One, in order for it to the drive to work, energy has to be expended to create a propulsive force. (ie. Thrust)

     Two, "for every action, there has to be an equal and opposite reaction".  Basic Newtonian Physics, not a hundred percent accurate, but close enough.

     Three, electricity is being used to create radio Frequencies within "The Device".

     Four, somehow, these "Radio Waves" are imparting their energy to "The Device" in such a way as to produce kinetic force.  (ie. Thrust)

     Five, the "Radio Waves" seem to be being expended in a direction opposite of the direction of thrust, if I understand the diagrams I have seen so far.

     Six, since energy is matter in a more coherent form than lasers or plasma, mass is being expended in a direction opposite the direction of motion.

     Seven, again, unless I am misunderstanding these diagrams, heat is being generated as part of this conversion of energy to thrust.

     Eight, in order to continue to generate thrust, more energy must be expended in order to generate RF, which is converted by "The Device" into heat and thrust.

     Nine, so, in order to generate thrust; mass, in the form of energy, is being expended and expelled in a direction of motion opposite of the direction of thrust, energy is being used to impart this motion. heat is being generated as a byproduct of this process, and an amount of energy, similar to or larger than the normal amount of energy needed to break free of inertia and produce thrust, is being used, and if no additional energy is applied to the device, it stops generating thrust.  I think that pretty much sums up what we know so far.

     So, Ten, it appears as though this device is a more efficient form of thrust convertion device than are chemical, plasma or nuclear rockets, which require mass be expended in the form of propellent, in order to produce thrust.  It appears that mass, in the form of electrons, in this case, are being expended in order to impart thrust, but doing so in a much more energy efficent manner.

     Finally, if "The Device" is indeed producing thrust in this manner, and we don't quite have a grasp on HOW it's doing what it does, (I'm pretty sure there is some very simple explaination that everybody is overlooking, as these things usually wind up being) I'm not really quite sure WHAT particular law of physics that it is violating. non-of the lawsof motion or thermodynamicsa appear to be violated on the face of it. So, if it is indeed producing thrust as all the tests so far seem to indicate, now all we need to do is figure out HOW it's doing it!
Heat is created by eddy currents in the walls of the cavity. They draw energy from the cavity energy, reducing stored cavity energy and cavity Q which is energy input per cycle to energy loss per cycle. This loss energy reduces cavity stored energy and thrust. The heat loss is not involved in thrust generation. It actually reduces thrust.

No mass is being expelled.

Please read: http://www.emdrive.com/theorypaper9-4.pdf

Simple question; Do electrons have mass?  If not, you are correct, if so, mass is being expended.  Perhaps minute quantities, but it IS being expended.

From Jefferson Labs in Virginia: Electron = 9.1093897*10-31 kg.

Yes electrons have very tiny mass and to get thrust you would need huge amounts of them traveling at near light speed. The energy demand would be huge and the radiation would cook you.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 02:20 PM
Yes electrons have very tiny mass and to get thrust you would need huge amounts of them traveling at near light speed. The energy demand would be huge and the radiation would cook you.
Please read Shawyer. www.emdrive.com

The higher the Q, the higher the effect of bouncing cavity stored energy mass on thrust. Shawyer has been doing this since 2003. Building real world devices that produce 1,000x the thrust of EW's mosquito thrust devices.

BTW nothing but waste eddy current heat leaves the cavity. Causes NO thrust. In fact reduces cavity Q, stored energy and thrust. This is why Shawyer / Cannae went to superconducting walls. to reduce wall eddy current losses that reduce cavity Q and reduce thrust force generation.

This is a real world almost self contained 2009 EMDrive device demo device that produces 25g thrust from 1.2 kW magnetron input energy: http://emdrive.com/demonstratorengine.html

Why was it NEVER publicly tested by NASA?
Hard to miss 214mN/kW thrust when pwr input is 1.2 kW. Should get 25g thrust. Can feel that with your hand.

Either is bends the EW thrust test system from over the top thrust generation or it is nothing. Simple to test. Ends all discussion about if it works or not.

Paul / Sonny why was this Shawyer demo 2009 EMDrive NEVER tested?
End the does it work or not speculation.
Test it.
Draw a line in the sand.
It works as claimed or it is nothing and time to move on.

Or is there an issue that Shawyer helped the Chinese to build their EMDrive, after the West rejected / called him a fraud and he is not welcome at the EW/NASA door?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 02:37 PM
That is what I was asking when I asked if it accelerated constantly. I mean constantly with constant power input. If power input is constant then total energy input increases linearly with time producing constant acceleration so velocity increases linearly with time. But kinetic energy increases with the square of velocity and so increases with the square of time.

Power input (electrical energy) is constant while energy output (kinetic energy) is growing much faster and at an ever increasing rate. That violates COE. That is because kinetic energy is proportional to the square of velocity.

If you had an electric car, 100% efficient and no friction losses, and gave it constant power input it would not accelerate constantly. It would start off with good acceleration but that would quickly fall to near zero as its velocity increased. You would need ever higher power inputs in order to just maintain constant acceleration. If your EMdrive works any different then it violates COE.
Deep space Ion / Hall thrusters have constant energy input, resultant constant thrust as long as fuel lasts. They accelerate the craft to faster and faster velocities.

EMDrive is no different, has constant energy input, resultant constant thrust, except it doesn't expel mass at a high velocity nor require fuel other than to supply the electricity generators.

A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.



Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 02:54 PM
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.

EMDrive does the same. Just no mass/ fuel is expelled, However some form of primary energy is used to generate electrical energy (as occurs in Ion / Hall thruster), which is then converted into kinetic energy and accelerates / decelerates the craft.

Different dog. same leg action.

Some form of primary energy is converted into kinetic energy.
COE is conserved.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: gospacex on 05/01/2015 03:16 PM
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.

EMDrive does the same.

Gosh.

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 05/01/2015 03:23 PM
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.

EMDrive does the same. Just no mass/ fuel is expelled, However some form of primary energy is used to generate electrical energy (as occurs in Ion / Hall thruster), which is then converted into kinetic energy and accelerates / decelerates the craft.

Different dog. same leg action.

Some form of primary energy is converted into kinetic energy.
COE is conserved.

I'll ask you to read this wikipedia article (http://en.wikipedia.org/wiki/Oberth_effect) before you make any further comment on rockets and conservation of energy. The fact that rockets have to bring their propellant with them is central to conservation of energy.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/01/2015 03:27 PM
Of course, your kinetic energy would be ridiculously high, thousands of times greater than the energy you put into the drive.

For .4N/kW and 40kg/kW specific power for a 1kW craft (weighing 40kg) just to make things easy:

(Kinetic Energy)/(Energy input)=
(.5*40kg*(92years*.4N/kW/(40kg/kW))^2)/(1kW*92years)
=
5806.5

Make no mistake, this is also a method to gain free energy.
Another useful meme is to beware of people who have simple answers to complex questions.

If Dr White's team is right this thruster is more akin to a propeller or the air breathing nuclear ramjet of project PLUTO, and the "reaction mass" are the virtual particles being preferentially accelerated by the system.

An interesting (but off topic) question would be does a virtual particle cease to exist entirely IE it's whole life is the single existence it's there for, or does it pop up "elsewhere," and is that "elsewhere" this universe, or another universe?

But let me ask you a simpler question.

Do you believe there is something there or IYHO it's all a set of experimental artifacts that have simply not been analyzed out thoroughly enough?

I was talking about the article, which suggests it is useful for interstellar travel and the article gave some example calculations. If you look at the kinetic energy from those equations and compare it to the energy input, you see they are orders of magnitude apart. No doubt it would be fantastic for interstellar travel. But by the same logic, you can get a huge amount of energy out of it, far more than you put in. Call that what you will, but those are the results.

And yes, never underestimate the ability to fool yourself. "The first principle is that you must not fool yourself, and you are the easiest person to fool." I think most people who have not had at least an undergraduate education in physics have a hard time appreciating this fact. And it's even worse in graduate school, where the training wheels start to come off, and you realize just how hard it is to puzzle out what's real and what isn't in experiments that are not set up for you by someone holding your hand through the whole thing. When this has been appreciated, then we can start talking about virtual particles and the like.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 03:39 PM
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.

EMDrive does the same. Just no mass/ fuel is expelled, However some form of primary energy is used to generate electrical energy (as occurs in Ion / Hall thruster), which is then converted into kinetic energy and accelerates / decelerates the craft.

Different dog. same leg action.

Some form of primary energy is converted into kinetic energy.
COE is conserved.

No, the constant power input of any rocket is an illusion created by not taking into account the energy used to accelerate your fuel. By pumping Kinetic energy into the fuel you are giving it more energy and so the power input of a rocket is far from constant.

Say I'm on roller skates and throw a brick converting one unit of my chemical energy to one unit of kinetic energy and gaining one unit of velocity. Now say I throw another brick using the same amount of chemical energy and gaining another unit of velocity. But since Ke goes with the square of velocity this time I have gained three units of Ke. Why did the first unit of chemical energy convert to one unit of Ke while the second unit of chemical energy convert to three units of Ke? And the next brick would convert one unit of chemical energy to five units of Ke. It seems like constant power input produces an ever increasing output. How do we resolve this paradox?

Well first I'm neglecting the weight of the bricks but the more important answer is that I'm neglecting the higher Kinetic energy of each successive brick. The first brick imparts some Ke into the second brick which must be taken into account when I throw the second brick. The input from the second brick is the chemical energy plus the Ke of the second brick. Thus the power input of my roller skate rock isn't really constant.

You cannot say the same about the EMdrive. It does not throw bricks and it does not carry reaction mass. Therefore the input power really is constant and the output really is ever increassing until it violates COE.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: AdrianW on 05/01/2015 03:59 PM
@TheTraveller: You seem to be misunderstanding very, very basic physical concepts (kinetic energy, closed/open systems, and conservation of energy), which is reflected by your inability to properly respond to ppnl's questions. I suggest you read up on these concepts if you want to participate in any reasonable discussion about advanced physics problems.

Hats off to ppnl for his/her patience in explaining the dilemma! :)

Note: I'm not saying that the reported effects are real or not. I'm also not saying that the EM drive works/doesn't work as advertised. Heck, I'd gladly throw relativity or the law of CoE in the trash if there's overwhelming evidence to the contrary. Right now, there really isn't.
Let's wait for further experimental evidence, whether it's supporting or refuting the claims.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: notsorandom on 05/01/2015 04:34 PM
This all pretty much boils down to two questions.
1. Is this device creating thrust? - Has not been ruled out that this is an artifact of the experiment but possible causes are being retired.
2. Can this device generate thrust in the stated application in space? - Dunno yet

This seems almost too good to be true. It is a small device and uses a manageable amount of power. This isn't like the warp drive theories which require negative density matter and all other sorts of unattainable or horrendously expensive things. When it comes to a lot of these other breakthrough propulsion concepts they are not realistically testable at this point. Debating the theory behind them is the most that can practically be done. This EM drive is different because it can be tested. This should be one particularly easy dragon to slay without even needing to worry about theory. So other labs should build and measure these things to build up rigor and drive down the chance there is something in the experiment causing this effect. If it still seems to work then fly a test in space. If it does what its supporters claim it will then I for one won't really care how it works. Not like I could understand it if I did care.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/01/2015 05:10 PM
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.

EMDrive does the same.

Gosh.

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.
EMDrive violates the Rocket Equation as no ISP from expelled high velocity fuel mass but not overall COE.

The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.

See Shawyer's equations for dynamic operation:
http://www.emdrive.com/theorypaper9-4.pdf

Apologies if my explanations fails to convey how EMDrive works different to expelled mass rocket engine. Suggest need to stop comparing to conventional rocket engine and focus on overall primary energy input to final accelerating mass kinetic energy gain.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: AdrianW on 05/01/2015 05:48 PM
The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.
This implies that there's a preferred frame of reference, which in turn implies that the thrust and the efficiency of the EM drive depends on it's orientation (because the Earth is moving through space) and on the time of day (because the Earth is rotating and thereby changing the experiment's velocity relative to the preferred frame of reference).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Raj2014 on 05/01/2015 05:59 PM
A lot of news websites have been posting about this. The news about the EM drive has grown a lot in the last two days. When they have done more testing and the results as promising. Soon it will be on the news channels. They should get a lot of funding. How many years will it be when we see this technology be used?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 06:01 PM
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.

EMDrive does the same.

Gosh.

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.
EMDrive violates the Rocket Equation as no ISP from expelled high velocity fuel mass but not overall COE.

The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.

See Shawyer's equations for dynamic operation:
http://www.emdrive.com/theorypaper9-4.pdf

Apologies if my explanations fails to convey how EMDrive works different to expelled mass rocket engine. Suggest need to stop comparing to conventional rocket engine and focus on overall primary energy input to final accelerating mass kinetic energy gain.

Actually he seems to be claiming that there is no constant acceleration with constant power input. If so then there may be no COE violation but we are back to the problem of a preferred frame of reference. And your ship will preform very differently in December than in June because of the orbit of the earth putting it in a different inertial reference frame.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Ghozer on 05/01/2015 06:14 PM
Has anyone thought simply on this?

It could be that the microwaves are causing miniature quantum explosions and what we're seeing with the interference of the lasers is a bubble created by the explosion (like a shockwave)

it's this quantum bubble that is causing the space around the bubble to alter - (displacement) and thus causing a quantum ripple of some sort..

What if it's like water - but an un-compressible quantum liquid?

I have always thought of space like a quantum liquid! :)

Forgive me but i'm no scientist or student have no qualifications or training in thermal dynamics, particle physics, or anything - i'm just a really interested person who has lots of thoughts and ideas - I could be way off the mark - but at least I have (now) found a place I can talk and discuss them :D
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: arachnitect on 05/01/2015 06:26 PM
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.

EMDrive does the same.

Gosh.

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.
EMDrive violates the Rocket Equation as no ISP from expelled high velocity fuel mass but not overall COE.

The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.

See Shawyer's equations for dynamic operation:
http://www.emdrive.com/theorypaper9-4.pdf

Apologies if my explanations fails to convey how EMDrive works different to expelled mass rocket engine. Suggest need to stop comparing to conventional rocket engine and focus on overall primary energy input to final accelerating mass kinetic energy gain.

Actually he seems to be claiming that there is no constant acceleration with constant power input. If so then there may be no COE violation but we are back to the problem of a preferred frame of reference. And your ship will preform very differently in December than in June because of the orbit of the earth putting it in a different inertial reference frame.

This is only a problem if you stubbornly insist that the increasingly dubious heliocentric THEORY is correct. There's a lot of empirical evidence that we actually live in a geocentric universe... maybe this device will help settle the question.

(teach the controversy!)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mongo62 on 05/01/2015 06:27 PM
The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.
This implies that there's a preferred frame of reference, which in turn implies that the thrust and the efficiency of the EM drive depends on it's orientation (because the Earth is moving through space) and on the time of day (because the Earth is rotating and thereby changing the experiment's velocity relative to the preferred frame of reference).

Couldn't it be a local inertial frame instead? With the inertial frame at any given point in space being tied to the local gravitational potential at that point (in this case, that of the Earth being dominant)?

(Actually the local inertial field, defined in this way, might just be the definition of the local gravitational field.)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: AdrianW on 05/01/2015 06:38 PM
Couldn't it be a local inertial frame instead? With the inertial frame at any given point in space being tied to the local gravitational potential at that point (in this case, that of the Earth being dominant)?
Only if that frame rotates with the Earth, I guess, otherwise the effect depends on the orientation of the device (I seem to remember that different orientations gave the same measurements, though I might be mistaken).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 06:54 PM
The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.
This implies that there's a preferred frame of reference, which in turn implies that the thrust and the efficiency of the EM drive depends on it's orientation (because the Earth is moving through space) and on the time of day (because the Earth is rotating and thereby changing the experiment's velocity relative to the preferred frame of reference).

Couldn't it be a local inertial frame instead? With the inertial frame at any given point in space being tied to the local gravitational potential at that point (in this case, that of the Earth being dominant)?

(Actually the local inertial field, defined in this way, might just be the definition of the local gravitational field.)

You could postulate a mechanism to react against the local gravitational gradient. This would solve the preferred frame problem and COE problem. But that isn't what the inventor claims, it isn't the theory he puts forward nor is there any other theory that would allow such a thing. It is more of an SF plot than a scientific theory.

For example I could claim that the moon is made of cheese by postulating a relatively thin crust of rock on top. You can always postulate some bogus mess that allows you to believe what you want. But when you do that you are doing science backwards.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jordan.greenhall on 05/01/2015 06:55 PM
Since Eagleworks started doing real work on the EM Drive, there has been growing interest from outside in finding ways to support their work. So far this has been frustrated largely due to NASA regulations (you can't donate money, equipment, etc. directly to a NASA project). There are some work-arounds ([through the SSI](www.ssi.org)) but these are uninspiring.

I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation.  My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.

Given that, I can see three more aggressive approaches to funding EM Drive research:

1) Convince the Eagleworks crew to take their work outside of NASA and fund the efforts directly. After some research I'm reasonably confident that some form of crowdfunding could be expected to be able to raise $2.5M to $5M for this kind of effort. Would that be enough to a) get the Eagleworks crew feeling safe to make the leap; and b) provide the materials and resources necessary to really kick the tires on this thing? Hard to say - but we should note that an effort like this would also open the doors on allowing interested allies loan equipment. Which is to say that you could likely get a nice multiplier on actual cash contributions.

2) Assemble some other team than the Eagleworks team and fund them to do the research in a similar manner to the above. This could be a sort of public/private combo where two teams collaborate to enhance each-other's work. The gating item here, of course, would be the team - what is the right mix of people to get this done right? 

3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.

Notably, we could really be innovative and use something like a cryptofunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.

I am in a position that I could organize any of these three and would be delighted to collaborate to make any of them happen.  Obviously, #1 is gated by the eagleworks team and #2 is gated by identifying and assembling an alternate team. 

I'm interested in the thoughts of those folks who have been close to the developments (and the people) so far.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/01/2015 06:59 PM
....
I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation.  My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.

....
Can you please further elaborate as to why you think this approach would be better than the present program to eventually have these tests replicated at NASA Glenn, JPL, John Hopkins or other academic institutions?

Is there an argument that can be made that this is a better approach than conducting the research at institutions like NASA and Universities, and proceeding to private funding once it has been scientifically replicated?

How would the effort differ from Roger Shawyer's setup at SPR in the UK for about 15 years?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 05/01/2015 07:01 PM
While your cavity and ours arn't exactly the same one could say the situations are quite similar.  The NASA Eagleworks system operated at 935MHz at (?)W, Roger Shawyer 2.45GHz at 850W, and Dr Yang at (?)MHz at 2.5KW (apologize if these missing values have been published, I didn't immediately see them).   
Welcome to the thread and the site.

Eagleworks studies were done around 100W power level. However they did comment that it needed an HDPE insert in the cavities to make it work.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jknuble on 05/01/2015 07:02 PM

Good luck, I can pass you some names off-line if that is of interest.   If you havn't already, it would be useful to consult a high-power RF engineer, not necessarily and EM physicist (sorry guys!  :) ).  As stated, I am not an expert on this phenomenon but if there are further questions I can perhaps pass them along.

-Joseph Knuble

(Also, I hope I'm wrong!)
My understanding is the current setup is a little over 1.9 GHz @ 50 watts.

From what I can find out online, the end caps of the cavity are single sided FR4, but I couldn't find out if they were baked and post coated or not. Do you think they could be getting some out gassing or other effects from the FR4? Would glass Teflon be a better choice of dielectric?

Is there a photo, drawing or block diagram of the current resonator I could see?  50W is lower than I expected to hear but that is still a large amount of power in the RF world and high power design techniques would still need to be employed.  FR4 and Teflon would both out-gas to some degree and I don't believe one is necessarily better than the other.   For either, the materials would need to be in the chamber for sufficient time to outgas enough prior to applying high power.

-JK
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/01/2015 07:07 PM
If you do a yahoo image search for "emdrive frustum" there are a few drawing by Dr. March ( the link didn't copy for me)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jordan.greenhall on 05/01/2015 07:10 PM
Largely to unconstrain the research from:

A) Resources allocated by these specific institutions;

B) Institutional politics

There is absolutely no reason why the efforts at Glenn, JPL, etc. couldn't or shouldn't be run in-parallel, but the ability to combine material resources with the open contribution of everyone in the world who is interested in the project ("open source R&D"?) presents a potentially powerful addition.  We have reason to believe (cf the original X-prize, the work at SpaceX, etc.) that these kinds of "entrepreneurial" R&D can do things that existing institutions can't.

I'd suggest, for example, that the synergy of many of the good folks on this forum with the work at Eagleworks (including notably your recent excellent article) is a sample of what could be done.  A properly architected crowd/funded + crowdsourced R&D effort could be extremely powerful.

It would differ from Dr. Shawyer's work in several ways:

1.  All results would be open and available to the public.  (In principle, any intellectual property would be public domain.) 
2.  There would be deliberate architectures in place to both engage and utilize the capacities of anyone who would be interested.  e.g., small teams who could take specific problems and run their own efforts supporting the broader effort.
3.  There would be substantial resources to enable the team to be relatively unconstrained in doing the necessary work. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/01/2015 07:12 PM
In order for White's proposed explanation to make any sense at all, you need to assume 3 things:

(1) momentum can be stored and propagated through virtual particle pairs that are created in the vacuum fluctuations of free space.  Call this the QVP.  Obviously this is White's controversial claim, but let's entertain the idea.

(2) storing momentum int the QVP must be "difficult".  If it were easy, then momentum would be lost into the QVP all the time, from all different types of interactions, and we wouldn't observe conservation of momentum in general.  For some reason, we must accept that the situation of standing waves in a specially shaped resonant cavity is a special situation that does enable momentum transfer into the QVP.

(3) it must be similarly difficult for the QVP to transmit momentum back into conventional particles.  If the QVP could easily give back momentum, then any virtual particles in the cavity that absorbed this momentum would just give it back when it interacted with the cavity walls, and there would be zero net thrust recorded.

Given assumptions (1) and (2) and (3), we can finally imagine that the EmDrive creates a sort of "wake" in the QVP behind it as described by White...in other words, momentum is transferred through the QVP from one virtual particle pair to the next, as a wave.

Honestly, these assumptions seem very implausible to me.  In particular, (3) seems even more difficult to accept than assumptions (1) or (2).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/01/2015 07:13 PM


Dr. Rodal:

"That amplitude, frequency and phase modulation of the carrier wave results in greater thrust force is a prediction from Dr. White's computer code, and not yet an experimentally proven fact."

I think I may have verified today the need for large time rate of change of the resonant circuit phase changes as the RF amplifier driven 1,937.088 MHz, +/- ~25kHz sine wave oscillates back and forth through the resonance frequency of the frustum cavity.  Through a methodical tuning campaign using our triple stub Z-matching tuner and 2 feet of RG-8 coax as the main transmission line to the frustum, I marched the Smith Chart solution circle around its impedance space while checking the thrust output for each over a dozen stub tuner configurations.   Only those tuning solutions that maximized the phase change through resonance over the smallest frequency span generated the largest thrust signatures and in fact it overcame its lower Q-factors that those solutions provided.  In fact a running solution that yielded Q-factor solutions as high as 7,500 were out performed by two or even three to one in thrust output by tuning solutions that had half these peak Q-factors, but maximized the resonant phase change per kHz.  And yes, the input power was maintained at around 50W for all tests.  More data later this week as I continue this investigation.

BTW, our Eagleworks Dynamics of the Quantum Vacuum paper has finally been published on the NASA/NTRS server.  You can find it here: 

http://tinyurl.com/mw64rsn

Best, Paul M.
JK: an earlier post by the good doctor with some details on the test setup.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Kansan52 on 05/01/2015 07:21 PM
"For example I could claim that the moon is made of cheese by postulating a relatively thin crust of rock on top. You can always postulate some bogus mess that allows you to believe what you want. But when you do that you are doing science backwards."

Except the Apollo lunar seismic experiment proved it was rock! (Sorry, couldn't help myself. Now back to our regularly scheduled program.)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: flux_capacitor on 05/01/2015 07:24 PM
While your cavity and ours arn't exactly the same one could say the situations are quite similar.  The NASA Eagleworks system operated at 935MHz at (?)W, Roger Shawyer 2.45GHz at 850W, and Dr Yang at (?)MHz at 2.5KW (apologize if these missing values have been published, I didn't immediately see them).   
Welcome to the thread and the site.

Eagleworks studies were done around 100W power level. However they did comment that it needed an HDPE insert in the cavities to make it work.

No, actually Eagleworks' RF power amplifiers has now power ranges of up to 125 W, but they used powers ranging from a few watts to 17W in experiments conducted in ambient air (see the original full paper (http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf)) then up to 50W in a hard vacuum (5×10−6 torr) but with a failing (arcing) RF amp, as stated in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608) by Paul March aka Star-Drive.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Art Harmon on 05/01/2015 07:25 PM
So let's assume the EM drive works as described and Alpha Centauri can be reached in approximately 130 earth years accounting for acceleration, cruising and  deceleration. Can anyone calculate the approximate time dilation spent? (i.e. the theory of relativity that shows  time slowing down relative to earth time and stops at light speed.) Obviously gravitational effects on time dilation would probably be impossible to factor in.

If time were slowed down enough would it allow reaching Alpha Centauri in a generation or two? Assuming one didn't die of radiation poisoning, a spec of dust piercing a hole through  them at that speed, or outright insanity.  ::)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/01/2015 07:25 PM
Largely to unconstrain the research from:

A) Resources allocated by these specific institutions;

B) Institutional politics

There is absolutely no reason why the efforts at Glenn, JPL, etc. couldn't or shouldn't be run in-parallel, but the ability to combine material resources with the open contribution of everyone in the world who is interested in the project ("open source R&D"?) presents a potentially powerful addition.  We have reason to believe (cf the original X-prize, the work at SpaceX, etc.) that these kinds of "entrepreneurial" R&D can do things that existing institutions can't.

I'd suggest, for example, that the synergy of many of the good folks on this forum with the work at Eagleworks (including notably your recent excellent article) is a sample of what could be done.  A properly architected crowd/funded + crowdsourced R&D effort could be extremely powerful.

Quote from: MIT physicist Marc Kastner
Competitors around the world are increasing their investment in basic research, but science funding in the U.S. federal budget is at "the lowest it has been since the Second World War as a fraction of the federal budget," says MIT physicist Marc Kastner, who led the committee that wrote the report. "This really threatens America's future."

http://www.infoworld.com/article/2917200/government/mit-report-cuts-to-federal-funding-threaten-the-countrys-future.html
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/01/2015 07:27 PM
3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.

Notably, we could really be innovative and use something like a cryptofunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.

This option is the best.  It encourages more people to collaborate and work on the project and prevents you from needing to identify and specifically put together a "dream team" or worrying about giving away the money to crackpots.  Also, I highly doubt that the Eagleworks team would accept quitting their jobs to temporarily work under some ad hoc crowdsourced funding.

While we are on the subject, I've been thinking about this lately and I would be even more interested in contributing to an independent campaign or prize to send a probe to explore the oceans of Titan for signs of life.  Titan is the only body in our solar system that might actually harbor macroscopic and prolific life on the surface, and yet we would never know it from the limited imagery gathered by Cassini-Huygens.

The Titan Mare mission was estimated to cost $425 million, less than the cost a single 747 aircraft, and would probably be capable of revealing to us whether or not there is macroscopic life "not as we know it" there.

http://en.wikipedia.org/wiki/Titan_Mare_Explorer
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: cfs on 05/01/2015 07:27 PM
Largely to unconstrain the research from:

A) Resources allocated by these specific institutions;

B) Institutional politics

There is absolutely no reason why the efforts at Glenn, JPL, etc. couldn't or shouldn't be run in-parallel, but the ability to combine material resources with the open contribution of everyone in the world who is interested in the project ("open source R&D"?) presents a potentially powerful addition.  We have reason to believe (cf the original X-prize, the work at SpaceX, etc.) that these kinds of "entrepreneurial" R&D can do things that existing institutions can't.

I'd suggest, for example, that the synergy of many of the good folks on this forum with the work at Eagleworks (including notably your recent excellent article) is a sample of what could be done.  A properly architected crowd/funded + crowdsourced R&D effort could be extremely powerful.

Quote
Competitors around the world are increasing their investment in basic research, but science funding in the U.S. federal budget is at "the lowest it has been since the Second World War as a fraction of the federal budget," says MIT physicist Marc Kastner, who led the committee that wrote the report. "This really threatens America's future."

http://www.infoworld.com/article/2917200/government/mit-report-cuts-to-federal-funding-threaten-the-countrys-future.html

The question is how do you convince enough people to donate to your cause via crowdfunding when the underlying science isn't even established?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/01/2015 07:29 PM
I like the X Prize idea.

That's exactly what I would do if I could.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ragingrei on 05/01/2015 07:30 PM
Since Eagleworks started doing real work on the EM Drive, there has been growing interest from outside in finding ways to support their work. So far this has been frustrated largely due to NASA regulations (you can't donate money, equipment, etc. directly to a NASA project). There are some work-arounds ([through the SSI](www.ssi.org)) but these are uninspiring.

I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation.  My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.

Given that, I can see three more aggressive approaches to funding EM Drive research:

1) Convince the Eagleworks crew to take their work outside of NASA and fund the efforts directly. After some research I'm reasonably confident that some form of crowdfunding could be expected to be able to raise $2.5M to $5M for this kind of effort. Would that be enough to a) get the Eagleworks crew feeling safe to make the leap; and b) provide the materials and resources necessary to really kick the tires on this thing? Hard to say - but we should note that an effort like this would also open the doors on allowing interested allies loan equipment. Which is to say that you could likely get a nice multiplier on actual cash contributions.

2) Assemble some other team than the Eagleworks team and fund them to do the research in a similar manner to the above. This could be a sort of public/private combo where two teams collaborate to enhance each-other's work. The gating item here, of course, would be the team - what is the right mix of people to get this done right? 

3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.

Notably, we could really be innovative and use something like a cryptofunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.

I am in a position that I could organize any of these three and would be delighted to collaborate to make any of them happen.  Obviously, #1 is gated by the eagleworks team and #2 is gated by identifying and assembling an alternate team. 

I'm interested in the thoughts of those folks who have been close to the developments (and the people) so far.

There are plenty of things in science that don't have an explanation for using modern understanding but that we find applications for -- the placebo effect, for example -- but I highly doubt anyone would have accepted as science any research into confirming the placebo effect if it hadn't been done in a completely academic setting.

Even if an independent group succeeds in replicating and isolating the phenomenon, it might take another Harold White to convince a reputable institution to take it seriously again -- and there aren't that many Harold Whites.

Ultimately the only reason people (myself included) are taking this seriously at all right now is because the experiments confirming the phenomenon were done at NASA. Once the major objections to the existence of a new phenomenon have been weeded out, I think people at more institutions will naturally begin to attempt to replicate and advance the experiments.

Crowdfunding might or might not work financially, but I don't think it'd be safe reputation-wise until everything can be ruled out that might potentially say the observations were all some kind of mistake. People will become even more skeptical than they are, and they'll begin to wonder if the crowdfunding money was the real motivation for the project all along.

I personally have nothing against crypto, but I do worry that working on what many consider to be alternative science using what most consider to be alternative currency would just bring the alternativeness of the project over the edge and turn a lot of people off. I also don't think there are any political impediments to the project. No one is trying to shut it down or hide it or anything (at least for now), so half of the value of crypto is moot.

Lastly, the research is slow-going, but it's not stalled. I'm as eager as anyone -- naysayer or not -- to see more come out of this, but the phrase "don't fix what isn't broken" comes to mind.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Peter NASA on 05/01/2015 07:33 PM
Some of the media aren't doing a great job translating what this excellent site has produced, but I think this news piece is great for being enthusiastic, correct, objective and interesting...

http://www.newsy.com/47123/
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jordan.greenhall on 05/01/2015 07:36 PM
"The question is how do you convince enough people to donate to your cause via crowdfunding when the underlying science isn't even established?"

This is a good question.  It will continue to be very challenging to get chunky private capital while the science is still leaning hard in the "science fiction" direction.  However, this is one of the areas where crowdsourcing can be very powerful indeed.  Far less compelling efforts have been crowd funded to the tunes of millions in recent years and after chatting with several groups in and around the crowdfunding/cryptofunding area, I have reasonable confidence that it could be accomplished. What would be necessary is:

* A clear statement of the intended objectives of the project.  My personal favorite is unimpeachable demonstration of material thrust. 

* A highly qualified team that gives a strong sense that the money donated will be wisely used - i.e. not wasted.

* A compelling (and also true!) story explaining why interested people should participate.

I look at this as a classic "white swan" event.  What are the chances that it is real?  Lets say 1%.  What are the consequences?  Game Changing.  Can something like this convince 50,000 people to part with $100?  Absolutely.   
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: cfs on 05/01/2015 07:36 PM
I like the X Prize idea.

That's exactly what I would do if I could.

Ditto - if this idea takes off I'd be happy to join any group that successfully gets the funding for this  :D
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/01/2015 07:36 PM
The question is how do you convince enough people to donate to your cause via crowdfunding when the underlying science isn't even established?

Simple.  All you need to do is get a number of smaller labs to replicate the experiment with positive results that sufficiently hype the entire internet up on the prospect of attainable interstellar travel which was previously thought impossible.  Oh, and it would help if one of those labs had the four letters "NASA" associated with it.  Now why does all this seem familiar?  Oh, right...because all that just happened.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JordanLeDoux on 05/01/2015 07:41 PM
I haven't been following these threads closely until recently, but I'm really curious if anyone here has examined whether or not Modified inertia from Hubble scale Casimir effects (MiHsC), which is a theory I just came across today, makes any sense at all. I never got far enough in math to really evaluate this level of physics on my own, but the "crackpot" alarms in my head didn't sound as I was reading about it.

The basics of it are, any object moving to the right will create an event horizon somewhere to left beyond which information cannot be observed. Like other event horizons, this will result in radiation (similar to Hawking radiation) called Unruh radiation. The wavelengths for this radiation are at normal accelerations on the order of light years.

But if you have something like a tube with light inside and reflective surfaces, the photons (because of their speed) will generate Unruh wavelength that are the exact resonant frequency of the tube.

In a uniform tube, this does nothing, but in a cone shaped tube, it would bias the direction of force toward the narrow end.

Again, this isn't my theory, it is proposed by a physicist at Plymouth U in the UK, but it seemed... reasonable.

The theory evidently also has the nice benefit of explaining the effects of dark matter and dark energy without any special tuning, and it explains how inertia works in general from what I was reading.

Does any of that make sense or sound plausible?

EDIT: I ask mainly because a device like the EmDrive is one of the only testable predictions that you could make with this theory given the technology we have now.

Hi Jordan,

Good summary. I have tested MiHsC on the emdrive & the results are encouraging / not conclusive, see my paper:

http://www.ptep-online.com/index_files/2015/PP-40-15.PDF

Best wishes,
Mike

Hey Mike. Thanks for replying! I was curious if you had any response to this objection that was raised to me elsewhere:

"What he derives is the Tully-Fisher relation but what he ignores is that the Tully-Fisher relation is empirical and it doesn't always give you an exponent of 4, in different bands (colours of light) you get a different answer.

The Tully-Fisher relation is not the issue (it can be explained by appealing to galaxy formation), the main issue is rotation curves which he hasn't shown he can explain. He claims all velocities should reduce to one universal number, but rotation curves don't all flatten out at one number that is the point of the Tully Fisher relation. Then there is gravitational lensing and the CMB power spectrum.

His CMB stuff is also wrong. He confuses the l=2 dipole term and the monopole to derive an expression which doesn't fit almost all of the power spectrum."
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RonM on 05/01/2015 07:43 PM
So let's assume the EM drive works as described and Alpha Centauri can be reached in approximately 130 earth years accounting for acceleration, cruising and  deceleration. Can anyone calculate the approximate time dilation spent? (i.e. the theory of relativity that shows  time slowing down relative to earth time and stops at light speed.) Obviously gravitational effects on time dilation would probably be impossible to factor in.

If time were slowed down enough would it allow reaching Alpha Centauri in a generation or two? Assuming one didn't die of radiation poisoning, a spec of dust piercing a hole through  them at that speed, or outright insanity.  ::)

From the article:

Quote
The speeds discussed in the Alpha Centauri mission proposal are sufficiently low that relativity effects are negligible.

http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/ (http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: flux_capacitor on 05/01/2015 07:47 PM
Sorry to be against the tide but: doesn't Xprize reward a team among others in competition, after some goal has been achieved?

Eagleworks' team doesn't need to be motivated. They don't need to be rewarded after they reach, say, a 1N milestone. Repeatable 1 newton of thrust and they will already have NASA and the whole world backing them, X-Prize or not. A lower goal, less impressive (millinewtons) and layman people won't even bother to donate. That would not make them dreaming.

Anyway, the issue is not within the goal itself.

The real problem is funding. Eagleworks needs money for equipments to run better experiments. They need money before they can reach any ambitious goal, and specifically they need money in order to reach that ambitious goal.

Or maybe there is something in X-Prize type funding that I do not know?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/01/2015 07:50 PM
a) the force measurements of the EM-drive,

They are inconsistent.  For example, with the EM Drive re-oriented, rotated by 180 degrees so that it points in the opposite direction, the measurements differ significantly.  Need to have consistent measurements replicated at several labs (NASA Glenn, JPL, John Hopkins have been mentioned) for the evidence to be conclusive. Also, even if the data would be consistent, and the EM Drive can be used for space propulsion, that would not be conclusive evidence that its operation is due to a degradable and mutable quantum vacuum as there are several other explanations being explored.

Propellant: The Earth's magnetic field? 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jordan.greenhall on 05/01/2015 07:53 PM

Quote
There are plenty of things in science that don't have an explanation for using modern understanding but that we find applications for -- the placebo effect, for example -- but I highly doubt anyone would have accepted as science any research into confirming the placebo effect if it hadn't been done in a completely academic setting.

Even if an independent group succeeds in replicating and isolating the phenomenon, it might take another Harold White to convince a reputable institution to take it seriously again -- and there aren't that many Harold Whites.

Ultimately the only reason people (myself included) are taking this seriously at all right now is because the experiments confirming the phenomenon were done at NASA. Once the major objections to the existence of a new phenomenon have been weeded out, I think people at more institutions will naturally begin to attempt to replicate and advance the experiments.

Crowdfunding might or might not work financially, but I don't think it'd be safe reputation-wise until everything can be ruled out that might potentially say the observations were all some kind of mistake. People will become even more skeptical than they are, and they'll begin to wonder if the crowdfunding money was the real motivation for the project all along.

I personally have nothing against crypto, but I do worry that working on what many consider to be alternative science using what most consider to be alternative currency would just bring the alternativeness of the project over the edge and turn a lot of people off. I also don't think there are any political impediments to the project. No one is trying to shut it down or hide it or anything (at least for now), so half of the value of crypto is moot.

Lastly, the research is slow-going, but it's not stalled. I'm as eager as anyone -- naysayer or not -- to see more come out of this, but the phrase "don't fix what isn't broken" comes to mind.

Your point on crowdcrypto as being a doubling-down on "edge" is well taken.  At the same time, the cure to that problem is simple: provide unimpeachable evidence that the phenomenon is real.  A multi newton thrust is more proof than an ocean of equations, simulations or presentations. 

Intriguingly, I find that the concern that "but I don't think it'd be safe reputation-wise until everything can be ruled out that might potentially say the observations were all some kind of mistake. People will become even more skeptical than they are, and they'll begin to wonder if the crowdfunding money was the real motivation for the project all along." is one of the more compelling reasons why a more entrepreneurial approach might be necessary.  When reputations and motivations are inhibiting efforts to get direct access to truth, something is broken. 

Let me reverse the discussion: assuming that material resources could be raised to fund R&D, what *harm* would it do to the effort?  Presumably the deep harm would be if the "private" R&D were irresponsible - lots of hype and little discipline; and this irresponsibility tarnished the entire concept making it impossible for responsible folks to try it on. 

Certainly a risk.  Implies that the X-prize approach would be the most appropriate. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jordan.greenhall on 05/01/2015 07:58 PM
Sorry to be against the tide but: doesn't Xprize reward a team among others in competition, after some goal has been achieved?

Eagleworks' team doesn't need to be motivated. They don't need to be rewarded after they reach, say, a 1N milestone. Repeatable 1 newton of thrust and they will already have NASA and the whole world backing them, X-Prize or not. A lower goal, less impressive (millinewtons) and layman people won't even bother to donate. That would not make them dreaming.

Anyway, the issue is not within the goal itself.

The real problem is funding. Eagleworks needs money for equipments to run better experiments. They need money before they can reach any ambitious goal, and specifically they need money in order to reach that ambitious goal.

Or maybe there is something in X-Prize type funding that I do not know?


Right.  The X-prize approach would appear to have two advantages:

1.  It would motivate *other* groups to begin work on trying to hit that milestone. 
2.  It would reward the Eagleworks team if they are able to get there first.

Thus it is a generalized way to increase the all-in probabilities of hitting the goal. 

Right now we are putting all of our collective chips on a largely unfunded group of folks doing this out of their own passion.  Seems that is a sub-optimal approach for something this impactful.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/01/2015 08:02 PM
Sorry to be against the tide but: doesn't Xprize reward a team among others in competition, after some goal has been achieved?

Eagleworks' team doesn't need to be motivated. They don't need to be rewarded after they reach, say, a 1N milestone. Repeatable 1 newton of thrust and they will already have NASA and the whole world backing them.

If a team engineers a device with 1N of thrust, then the entire world would be skeptical of them...and they might have a very difficult time getting contracts simply because people won't take them seriously.  In order to take them seriously, they would need to divulge all the details of their experiments and subject it to public scrutiny -- but if they do this, they completely lose their competitive advantage.  If it turns out to be valid, then larger companies like Boeing etc would immediately jump in and beat them out of the market.

Thus, by creating an XPrize like goal, that becomes a financial objective thats easier to shoot for and will encourage more teams to take on the time and risk of development.

NASA teams cannot accept direct contributions, and the NASA Eagleworks team is not necessarily the best suited team to solve this problem -- and their theories of how it works might be completely wrong, even if it does work.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: rgreen on 05/01/2015 08:04 PM
I read the article and have been looking through a lot of the main thread. Very interesting stuff, though most is over my head. As a chemist, I can't help but wonder about what's going on with the copper surface of the frustum. A quick back of the envelope (well, python) calculation shows that there's certainly enough energy in these devices to somehow atomize a small amount of copper , and propel them with enough momentum to produce a small amount of thrust. I'm not sure what the mechanism of atomization would be.

For example, a 30 watt emdrive where 0.001% of the energy went towards atomization and 1% went toward addtional momentum of the particles... You'd have a device with 91uN thrust, propelling 1.4ng of copper a second at 65500m/s.

I know it's far-fetched, but have they stuck an ion detector behind the thing? Have they looked at the surface with SEM for signs of corrosion?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ragingrei on 05/01/2015 08:10 PM

Quote
There are plenty of things in science that don't have an explanation for using modern understanding but that we find applications for -- the placebo effect, for example -- but I highly doubt anyone would have accepted as science any research into confirming the placebo effect if it hadn't been done in a completely academic setting.

Even if an independent group succeeds in replicating and isolating the phenomenon, it might take another Harold White to convince a reputable institution to take it seriously again -- and there aren't that many Harold Whites.

Ultimately the only reason people (myself included) are taking this seriously at all right now is because the experiments confirming the phenomenon were done at NASA. Once the major objections to the existence of a new phenomenon have been weeded out, I think people at more institutions will naturally begin to attempt to replicate and advance the experiments.

Crowdfunding might or might not work financially, but I don't think it'd be safe reputation-wise until everything can be ruled out that might potentially say the observations were all some kind of mistake. People will become even more skeptical than they are, and they'll begin to wonder if the crowdfunding money was the real motivation for the project all along.

I personally have nothing against crypto, but I do worry that working on what many consider to be alternative science using what most consider to be alternative currency would just bring the alternativeness of the project over the edge and turn a lot of people off. I also don't think there are any political impediments to the project. No one is trying to shut it down or hide it or anything (at least for now), so half of the value of crypto is moot.

Lastly, the research is slow-going, but it's not stalled. I'm as eager as anyone -- naysayer or not -- to see more come out of this, but the phrase "don't fix what isn't broken" comes to mind.

Your point on crowdcrypto as being a doubling-down on "edge" is well taken.  At the same time, the cure to that problem is simple: provide unimpeachable evidence that the phenomenon is real.  A multi newton thrust is more proof than an ocean of equations, simulations or presentations. 

Intriguingly, I find that the concern that "but I don't think it'd be safe reputation-wise until everything can be ruled out that might potentially say the observations were all some kind of mistake. People will become even more skeptical than they are, and they'll begin to wonder if the crowdfunding money was the real motivation for the project all along." is one of the more compelling reasons why a more entrepreneurial approach might be necessary.  When reputations and motivations are inhibiting efforts to get direct access to truth, something is broken. 

Let me reverse the discussion: assuming that material resources could be raised to fund R&D, what *harm* would it do to the effort?  Presumably the deep harm would be if the "private" R&D were irresponsible - lots of hype and little discipline; and this irresponsibility tarnished the entire concept making it impossible for responsible folks to try it on. 

Certainly a risk.  Implies that the X-prize approach would be the most appropriate.

I think creating multi-newton thrust at this point would require much better equipment, which means more money. So we end up back with the chicken-egg problem, except, at risk of taking the idiom a little too far, they already have an egg, and I can't see a reason for them to hurry it into a chicken.

For something that hasn't even been published yet, I think the amount of information Eagleworks is sharing is pretty unusual. Access to truth doesn't seem to be an issue.

There are a bajillion cosmetics companies selling age-reversal products meant both cosmetically and literally, and while I believe that some (if not many) of their claims are indeed true, they're so buried in snake oil and marketing mumbojumbo that no one knows what of it to take seriously at all. Many of these companies are extremely profitable and well-respected in the business community. I worry that even if something can be demonstrated visibly moving, if it were to come from a private or enthusiast-funded group, people will continue to question it.

I mean, just look at all the supposed perpetual motion and free energy machine videos on YouTube. The only way I would even give them a second thought is if they came from an institution like NASA or if they didn't appear to violate fundamental laws of physics. EM Drive does the latter, so the former is the only reason people still have optimism.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jknuble on 05/01/2015 08:12 PM
While your cavity and ours arn't exactly the same one could say the situations are quite similar.  The NASA Eagleworks system operated at 935MHz at (?)W, Roger Shawyer 2.45GHz at 850W, and Dr Yang at (?)MHz at 2.5KW (apologize if these missing values have been published, I didn't immediately see them).   
Welcome to the thread and the site.

Eagleworks studies were done around 100W power level. However they did comment that it needed an HDPE insert in the cavities to make it work.

No, actually Eagleworks' RF power amplifiers has now power ranges of up to 125 W, but they used powers ranging from a few watts to 17W in experiments conducted in ambient air (see the original full paper (http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf)) then up to 50W in a hard vacuum (5×10−6 torr) but with a failing (arcing) RF amp, as stated in this post (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608) by Paul March aka Star-Drive.

Thanks! I had not seen the original paper, only the abstract.  I note they claim in effect even as low as 2.6W (although, not repeatable?).  That does seem quite low.  I'll ask a few guys involved with our diplexer investigation and see what they think.

-JK
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Vballer18 on 05/01/2015 08:12 PM
a) the force measurements of the EM-drive,

They are inconsistent.  For example, with the EM Drive re-oriented, rotated by 180 degrees so that it points in the opposite direction, the measurements differ significantly.  Need to have consistent measurements replicated at several labs (NASA Glenn, JPL, John Hopkins have been mentioned) for the evidence to be conclusive. Also, even if the data would be consistent, and the EM Drive can be used for space propulsion, that would not be conclusive evidence that its operation is due to a degradable and mutable quantum vacuum as there are several other explanations being explored.

Propellant: The Earth's magnetic field?

Momentum can be conserved if the em waves are pushing against Higgs bosons, which should be detectable by a deformation in the local Higgs field. This would mean that the engine would lose efficiency outside of the Oort Cloud in the Alpha Centauri scenario.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: flux_capacitor on 05/01/2015 08:30 PM
About crowd-funding and all ideas to find a way to circumvent NASA's inability to accept any donation, I understand the excitement and that you all know the ins and outs. But keep in mind one thing:

In most people's head, NASA is a powerful and magical organization populated by top-level scientists and engineers wearing glasses and white smocks, working in clean and marvelous big labs like the one you can see in the last Pixar movie Big Hero 6.

Those people do not know the struggling of a scientist to get just a little more funding in their lab where only 3 or 4 other colleagues work with them. Eagleworks has an old dying RF amp and they do not even have the bucks to replace it… Paul had to build the copper frustum at home, in his wife's dining room! Really people would be shocked if they knew that.

On the opposite, the tweetosphere already believes NASA is secretly working on the U.S.S. Enterprise after having accidentally invented a warp drive in their best gigantic 1000 sq.ft underground secret lab… OK I exaggerate a bit, but have you read all those articles in the media with the picture of the Star Trek spaceship? This has triggered people's attention.

And now you want to explain people in the streets they should donate their money to NASA? They will answer: "What? They've invented that warp engine to explore the universe, but they can't even build it to change mankind's future? WTF where does my tax go? Come on guys, you're NASA!"

The problem is not with people, it's with NASA, and right up there, with funding from the congress. And how science and its relationships with politics (and military…) is taught at school. How to really help I don't know :(
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/01/2015 08:31 PM
And now we have a pretty good video, objective  (even including Sean Carroll from CalTech, and Alcubierre stating that he thinks his warp-drive concept is not practically feasible for centuries) about the NSF article on the EM Drive !

http://www.newsy.com/47123/

 :)

There is some hope for the media, as these guys got this "right", fair and balanced, respecting science and yet keeping up some hope and they put the video together in a short amount of time
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/01/2015 08:33 PM
A test that should be performed:

NASA Eagleworks should very precisely measure the mass of the test article, and verify that it is not losing any mass while it is generating force.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: zen-in on 05/01/2015 08:38 PM
Sorry to be against the tide but: doesn't Xprize reward a team among others in competition, after some goal has been achieved?

Eagleworks' team doesn't need to be motivated. They don't need to be rewarded after they reach, say, a 1N milestone. Repeatable 1 newton of thrust and they will already have NASA and the whole world backing them.

If a team engineers a device with 1N of thrust, then the entire world would be skeptical of them...and they might have a very difficult time getting contracts simply because people won't take them seriously.  In order to take them seriously, they would need to divulge all the details of their experiments and subject it to public scrutiny -- but if they do this, they completely lose their competitive advantage.  If it turns out to be valid, then larger companies like Boeing etc would immediately jump in and beat them out of the market.

Thus, by creating an XPrize like goal, that becomes a financial objective thats easier to shoot for and will encourage more teams to take on the time and risk of development.

NASA teams cannot accept direct contributions, and the NASA Eagleworks team is not necessarily the best suited team to solve this problem -- and their theories of how it works might be completely wrong, even if it does work.

If the Eaglework's apparatus could consistently produce a force of just 100 microNewtons in forward and reverse configuration I would be convinced.   To their credit they have provided a lot of information about their experiments and have disclosed sources of error and what they have done to mitigate these errors.   However as these error sources have been mitigated it appears the thrust has also decreased.   Without knowing any more details about their experiments, the protocol they use, and any unpublished null results I can still unequivocally state there is no thrust being produced because none of the claimed thrust  waveforms show the same response as the calibration pulse (a capacitor).   Instead the thrust waveforms show thermal and mechanical deformation responses.    I think they should continue their research but they should be doing some tests that rule out conventional explanations.   Earlier I stated they should heat the cavity with a DC power source and measure the response (apparent movement which is construed as a force).   This is different from the dummy load test where the dummy load did not heat up the cavity.
As to crowd funding or some kind of prize, I would not be one to say no to that.   However any prize should not be limited to this technology because it will eventually be proven to be inconclusive as the measured "thrust" decreases further.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ragingrei on 05/01/2015 08:43 PM
And now we have a pretty good video, objective  (even including Sean Carroll from CalTech, and Alcubierre stating that he thinks his warp-drive concept is not practically feasible for centuries) about the NSF article on the EM Drive !

http://www.newsy.com/47123/

 :)

There is some hope for the media, as these guys got this "right", fair and balanced, respecting science and yet keeping up some hope and they put the video together in a short amount of time

I'm glad for that. I wrote an article in the pop sci column of the local Japanese community magazine I work for, and it was very much the same description of the current situation as in this video, along with a little history beginning with Shawyer's work.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/01/2015 08:48 PM
As to crowd funding or some kind of prize, I would not be one to say no to that.   However any prize should not be limited to this technology because it will eventually be proven to be inconclusive as the measured "thrust" decreases further.

This is a good point.  Any prize that is set up should be general enough that it is "winnable" by a successful demonstration of something like an EmDrive, but also that it does not immediately become irrelevant if the EmDrive concept is shown to be a fluke.

I propose, as an objective, any propellentless thruster that generates more thrust than a perfectly efficient photon drive.

On the other hand, if the EmDrive is shown to be a mistake, I think most people would go back to saying that "this is impossible" and a waste of time to even think about.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/01/2015 08:49 PM
Well if it sparks a slight uptick in the people's interest in space then even that is a positive development.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: BL on 05/01/2015 08:59 PM
"The real problem is funding. Eagleworks needs money for equipments to run better experiments. They need money before they can reach any ambitious goal, and specifically they need money in order to reach that ambitious goal."

I am a newby and have little interest in the 'down and dirty' theoretical goings on here, since I can't do the math, but I AM interested in anything that would help Eagleworks with their testing.  I am not a 'true believer', but I am definitely a 'true hoper'.

There is apparently a pool of people, including Jordan Greenhall, who have access to funds and/or people to speed the process along but:

NASA can't accept private funding.

NASA can't accept volunteer labor.

How about having Eagleworks come up with a dream list of equipment that they think would help them advance the process, pass it to Mr. Greenhall (for example) have Mr. Greenhall assemble the package, and then lease the equipment to Eagleworks for a VERY attractive fee?

For example, there has been recent speculation that pure CW is not the optimum signal source, and suggesting that a ‘dirty’ magnetron would work better.  However, the spectral output of  a magnetron is neither predictable or controllable.  How about using something like a Vector Signal Generator similar to this:

 http://literature.cdn.keysight.com/litweb/pdf/5991-0038EN.pdf

This would allow precision tailoring of the output spectrum as well as providing an extremely clean CW source with millihertz resolution.  It would also allow computer control of the output frequency to compensate for changes in the resonant frequency of the thruster as it heated. ( Or, hopefully, as it mechanically deformed when producing prodigious thrust.)

It could be used to drive an amplifier similar to this these: 

http://www.ifi.com/index.php/amplifiers/twt-amplifiers/343-t-200-a-t-250-series-high-power-twt-microwave-power-amplifiers.html

which provide a couple of hundred watts of power and are stable into any load.  More money buys more power.

Other problems such as obtaining vacuum rated amplifiers and spurious signals from DC currents inside the test chamber could possibly be addressed by using Mulletron’s suggestion from the original thread:  couple the energy onto the pendulum via an air gap TX/RX link, with all active components outside the chamber.  The signal would be passed into the chamber via coax or waveguide feedthroughs.  According to Mulletron, he built and tested a rudimentary link and found that the coupling loss was in the range of a dB.  An air gap using standard gain horns similar to these:

http://www.pasternack.com/standard-gain-horn-antennas-category.aspx

would probably do better.

At any rate, I agree with several of the other posters:  the important thing is to obtain incontrovertible evidence of SOME thrust.  If THAT is obtained, money will be no problem and theory can catch up.  Of course incontrovertible evidence that NASA, the Chinese, and Shswyer test procedures were flawed, identifying the flaws, correcting the flaws, and proving that with rigorous testing there was NO thrust would ALSO be valuable, but not what I am hoping for.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: PaulF on 05/01/2015 09:09 PM
Since Eagleworks started doing real work on the EM Drive, there has been growing interest from outside in finding ways to support their work. So far this has been frustrated largely due to NASA regulations (you can't donate money, equipment, etc. directly to a NASA project). There are some work-arounds ([through the SSI](www.ssi.org)) but these are uninspiring.

I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation.  My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.

Given that, I can see three more aggressive approaches to funding EM Drive research:

1) Convince the Eagleworks crew to take their work outside of NASA and fund the efforts directly. After some research I'm reasonably confident that some form of crowdfunding could be expected to be able to raise $2.5M to $5M for this kind of effort. Would that be enough to a) get the Eagleworks crew feeling safe to make the leap; and b) provide the materials and resources necessary to really kick the tires on this thing? Hard to say - but we should note that an effort like this would also open the doors on allowing interested allies loan equipment. Which is to say that you could likely get a nice multiplier on actual cash contributions.

2) Assemble some other team than the Eagleworks team and fund them to do the research in a similar manner to the above. This could be a sort of public/private combo where two teams collaborate to enhance each-other's work. The gating item here, of course, would be the team - what is the right mix of people to get this done right? 

3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.

Notably, we could really be innovative and use something like a cryptofunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.

I am in a position that I could organize any of these three and would be delighted to collaborate to make any of them happen.  Obviously, #1 is gated by the eagleworks team and #2 is gated by identifying and assembling an alternate team. 

I'm interested in the thoughts of those folks who have been close to the developments (and the people) so far.
Hi all, and Jordan,

I read your post with the three options, and I also noticed people favor option #3.

I am myself at the moment working on a business plan which quite coincidentally is to propose a large-scale Wi-Fi network in the Port of Rotterdam. I enjoy entrepreneuring, this is my first time so fingers crossed :)

As a business man, I would like to point out that offering a prize will make teams secretive about their work and probably also will mean the working results will be patented. And we all know what that means as far as this revolution becoming public domain....

Unless contracts are signed prohibiting this, this will happen (at least I fear it). The problem with contracts is that they are contracts. And we don't really want those.

I am not ramming option #3 into the ground, I think it is a good idea initially. But corruption is in the heart of every human I'm afraid, especially when it comes to money.

Now I am not completely up to speed ont he tread, so someone else might have pointed this out already. My apologies in that case.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: bad_astra on 05/01/2015 09:13 PM

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.

Does a magsail?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: cfs on 05/01/2015 09:25 PM
Since Eagleworks started doing real work on the EM Drive, there has been growing interest from outside in finding ways to support their work. So far this has been frustrated largely due to NASA regulations (you can't donate money, equipment, etc. directly to a NASA project). There are some work-arounds ([through the SSI](www.ssi.org)) but these are uninspiring.

I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation.  My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.

Given that, I can see three more aggressive approaches to funding EM Drive research:

1) Convince the Eagleworks crew to take their work outside of NASA and fund the efforts directly. After some research I'm reasonably confident that some form of crowdfunding could be expected to be able to raise $2.5M to $5M for this kind of effort. Would that be enough to a) get the Eagleworks crew feeling safe to make the leap; and b) provide the materials and resources necessary to really kick the tires on this thing? Hard to say - but we should note that an effort like this would also open the doors on allowing interested allies loan equipment. Which is to say that you could likely get a nice multiplier on actual cash contributions.

2) Assemble some other team than the Eagleworks team and fund them to do the research in a similar manner to the above. This could be a sort of public/private combo where two teams collaborate to enhance each-other's work. The gating item here, of course, would be the team - what is the right mix of people to get this done right? 

3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.

Notably, we could really be innovative and use something like a cryptofunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.

I am in a position that I could organize any of these three and would be delighted to collaborate to make any of them happen.  Obviously, #1 is gated by the eagleworks team and #2 is gated by identifying and assembling an alternate team. 

I'm interested in the thoughts of those folks who have been close to the developments (and the people) so far.
Hi all, and Jordan,

I read your post with the three options, and I also noticed people favor option #3.

I am myself at the moment working on a business plan which quite coincidentally is to propose a large-scale Wi-Fi network in the Port of Rotterdam. I enjoy entrepreneuring, this is my first time so fingers crossed :)

As a business man, I would like to point out that offering a prize will make teams secretive about their work and probably also will mean the working results will be patented. And we all know what that means as far as this revolution becoming public domain....

Unless contracts are signed prohibiting this, this will happen (at least I fear it). The problem with contracts is that they are contracts. And we don't really want those.

I am not ramming option #3 into the ground, I think it is a good idea initially. But corruption is in the heart of every human I'm afraid, especially when it comes to money.

Now I am not completely up to speed ont he tread, so someone else might have pointed this out already. My apologies in that case.

A frequent practice in academia especially among experimental groups is collaborative competition whereby the entire collaboration is split into teams which communicate with each other openly about their respective projects, but compete in order to be the first to obtain definitive results.  If something like this could be fostered it would be the best option to really finding out if we have something here... but I don't know how one would apply this in principle outside of academia.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/01/2015 09:25 PM
If your in the US, please write or email your senators and congressman, and let them know how important proper funding for NASA is to our future. Let them know you think underfunding NASA is BAD public policy. If they hear it enough from enough people they might be more receptive to funding requests.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/01/2015 09:28 PM

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.

Does a magsail?

A magsail is neither constant acceleration nor reaction-less. It is true that it does not carry its reaction mass with it but it is reacting against an external medium. But then so does a car, airplane or boat.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: jknuble on 05/01/2015 09:35 PM
A test that should be performed:

NASA Eagleworks should very precisely measure the mass of the test article, and verify that it is not losing any mass while it is generating force.

Similar idea:  Talking to a colleague involved in our breakdown issues, he suggested a repeated test with a TQCM added to the chamber. (Looking over the paper*, it isn't clear if this was done or not.) Pull a decent vacuum until all out-gassing events have subsided. Then turn on your RF power. If particles are being generated by dielectric breakdown you will see them on the TQCM. This was used to validate that breakdown was occurring in our diplexer and not some other purely RF effect. 

He also points out that maybe this isn't a bad thing!  Perhaps a solid dielectric as your fuel could last a very long time...

-JK

*http://arc.aiaa.org/doi/pdf/10.2514/6.2014-4029
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/01/2015 09:39 PM
So let's assume the EM drive works as described and Alpha Centauri can be reached in approximately 130 earth years accounting for acceleration, cruising and  deceleration. Can anyone calculate the approximate time dilation spent? (i.e. the theory of relativity that shows  time slowing down relative to earth time and stops at light speed.) Obviously gravitational effects on time dilation would probably be impossible to factor in.

If time were slowed down enough would it allow reaching Alpha Centauri in a generation or two? Assuming one didn't die of radiation poisoning, a spec of dust piercing a hole through  them at that speed, or outright insanity.  ::)

I get around a month difference.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/01/2015 09:39 PM
A frequent practice in academia especially among experimental groups is collaborative competition whereby the entire collaboration is split into teams which communicate with each other openly about their respective projects, but compete in order to be the first to obtain definitive results.  If something like this could be fostered it would be the best option to really finding out if we have something here... but I don't know how one would apply this in principle outside of academia.

Easy: Don't.  Offer a prize to teams in academia, such that the results of their work are public domain. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mongo62 on 05/01/2015 10:18 PM

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.

Does a magsail?

A magsail is neither constant acceleration nor reaction-less. It is true that it does not carry its reaction mass with it but it is reacting against an external medium. But then so does a car, airplane or boat.

It is argued that the EM-drive is also reacting against an external medium, in its case the quantum vacuum.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 05/01/2015 10:42 PM
Well, here's a quick synopsis of my summary:

1: There is a substantial inconsistency between results obtained in one orientation and the opposite orientation. This means there are unaccounted-for errors of comparable magnitude to the effect. The onus is on the proponents to eliminate such errors, not on the opponents to calculate the errors precisely (the insistence that the opposite is true is hallmark of pseudoscience).

What was the pair of the graphs again? Rodal, can you at least include them in the article, to avoid misleading the public?

2: Independent replication is less than none. The results are not replicated with the same apparatus in the same lab, when the device is turned 180 degrees. Note: mere presence of a thrust does not constitute a replication; the experiments should be consistent as inconsistency implies some environmental effect.

3: 217 years ago, Henry Cavendish has measured forces smaller than a single pixel on any of the force plots here, and he made an error of 1.1%. This really is mind blowing. What did go so wrong here?

4: A far simpler experimental set up directly based upon that used by Henry Cavendish, if used on an enclosed shielding box containing the apparatus and batteries, would not be subject to emissions by the test article and would obtain far higher accuracy, at a far lower cost, while screening out most of the conventional forces (as those would act between the drive and it's enclosure, netting zero for the whole).

It would also permit easy testing in 10 degree increments to rule out interactions with Earth's magnetic field, and to shed light on the important theoretical questions with regards to the interaction of the force with Earth's orbital motion, dark matter flux through the cavity, neutrino flux through the cavity, et cetera et cetera. Placement of test masses around the article could clarify whenever this is a long range force or a short range one acting between the drive and the environment.

When it comes to the drive itself, due to much higher sensitivity of the 217 years old design, lower power levels could be employed, simplifying the construction and alleviating material degradation within the cavity.

5: Such significant unknown coupling between EM radiation and anything else would interfere with operation of many telecommunication and radar devices as well as many common laboratory items, which are sensitive to any deviations from Maxwell's equations and quantum electrodynamics, down to parts per trillion. If the momentum is conserved, microwaves can not be producing thrust without a corresponding reaction on the microwaves. As the EM radiation pressure is very low (incident and reflected power divided by the speed of light), even very small forces correspond to very huge deviations from Maxwell's equations.

Anyhow, all in all it looks really bad.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: R.W. Keyes on 05/01/2015 10:48 PM
Since Eagleworks started doing real work on the EM Drive, there has been growing interest from outside in finding ways to support their work. So far this has been frustrated largely due to NASA regulations (you can't donate money, equipment, etc. directly to a NASA project). There are some work-arounds ([through the SSI](www.ssi.org)) but these are uninspiring.

I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation.  My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.

Given that, I can see three more aggressive approaches to funding EM Drive research:

1) Convince the Eagleworks crew to take their work outside of NASA and fund the efforts directly. After some research I'm reasonably confident that some form of crowdfunding could be expected to be able to raise $2.5M to $5M for this kind of effort. Would that be enough to a) get the Eagleworks crew feeling safe to make the leap; and b) provide the materials and resources necessary to really kick the tires on this thing? Hard to say - but we should note that an effort like this would also open the doors on allowing interested allies loan equipment. Which is to say that you could likely get a nice multiplier on actual cash contributions.

2) Assemble some other team than the Eagleworks team and fund them to do the research in a similar manner to the above. This could be a sort of public/private combo where two teams collaborate to enhance each-other's work. The gating item here, of course, would be the team - what is the right mix of people to get this done right? 

3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.

Notably, we could really be innovative and use something like a cryptofunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.

I am in a position that I could organize any of these three and would be delighted to collaborate to make any of them happen.  Obviously, #1 is gated by the eagleworks team and #2 is gated by identifying and assembling an alternate team. 

I'm interested in the thoughts of those folks who have been close to the developments (and the people) so far.

These would all be good methods in another field. I don't think they're appropriate here. It's hard to pull work out of NASA, not by intellectual property issues but by the scientists not wanting to leave NASA. I don't know how "entrepreneurial" the Eagleworks scientists are, but I suspect that they are more interested in doing science than engineering. There's no shortage of great things going on at Eagleworks and NASA. I wouldn't want the work that Eagleworks does to become proprietary, or become sucked into the Silicon-Valley venture-capitalist mode of thought in any way. That's not to sat that others shouldn't take up refining the science into engineering. There are other groups working on this, but they're not talking, either because it's defense related and the work is secret, or because there is a commercial need for a low profile. I don't think the Chinese have backed off their research, nor have Boeing, and Roger Shawyer/SPR are engaged in something as well. A few years ago, I was exchanging email with Roger over the EMDrive and related topics, but he's become quite hushed lately - I think that he doesn't want to mix up my ideas with his and create any doubts regarding intellectual property. By the way, he has filed for (and I believe has been granted) patents related to the EMDrive. To move forward commercially, you would have to either come to an agreement with him/SPR, or wait for his patents to expire, or find some way around them. I'd guess that Guido Fetta has also protected his invention as well.

I think the best way to support Eagleworks is through vocal and active political support. This means support not only of NASA, but of Eagleworks specifically. I have thought of the idea of utilizing the whitehouse online petition system as a way to direct more resources to Eagleworks directly, but I'd need to hear what Eagleworks thinks they need as far as resources and other support, and then craft the petition.

Hi all, and Jordan,

I read your post with the three options, and I also noticed people favor option #3.

I am myself at the moment working on a business plan which quite coincidentally is to propose a large-scale Wi-Fi network in the Port of Rotterdam. I enjoy entrepreneuring, this is my first time so fingers crossed :)

Paul, I have been involved with WiFi mesh networks in the past, for public Internet access. I know people who have done this in other places, and had much more success than I did in Cambridge/Boston, such as in Vienna. I don't want to drift off topic any further, so contact me and we can speak privately, if you'd like.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KelvinZero on 05/01/2015 10:57 PM
It is argued that the EM-drive is also reacting against an external medium, in its case the quantum vacuum.
The important question is whether this medium, whatever it is, is fixed (like a plane moving through air and a boat through water) or always seems stationary in your current frame in which case you can get more energy than you put in. This wouldn't kill the idea but it would make it puzzling to only focus on the application as a better ion drive.

There comparatively straightforward drives that propose pushing against the interstellar medium (the very thin ionised gas between stars), for example http://en.wikipedia.org/wiki/Bussard_ramjet#Electrostatic_ion_scoop
Potentially these could far outperform a rocket because a rocket has to carry its own reaction mass and that gets exponentially bad. Pushing on a fixed medium would allow a mere square relationship between energy and velocity. This velocity is relative the the medium. I think I read somewhere that we are moving through the interstellar medium at about 30km/s but I couldnt find the reference.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: neuroMatt on 05/01/2015 11:01 PM


Is there a photo, drawing or block diagram of the current resonator I could see?  50W is lower than I expected to hear but that is still a large amount of power in the RF world and high power design techniques would still need to be employed.  FR4 and Teflon would both out-gas to some degree and I don't believe one is necessarily better than the other.   For either, the materials would need to be in the chamber for sufficient time to outgas enough prior to applying high power.

-JK

Not having worked much with high power RF in a vacuum I'll talk about the non-vac testing. Assuming there's some kind of corona, since the cavity is closed, wouldn't the corona be on the inside of the cavity and therefore apply equal force in both directions when the particles bounce off the other side of the cavity? The cavity is sealed so I'm not sure what amount of leakage would be needed to produce this kind of thrust, but the particles released from the surface by the corona effect should be mostly reflected internally keeping all the momentum cancelled out.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 05/01/2015 11:02 PM
It is argued that the EM-drive is also reacting against an external medium, in its case the quantum vacuum.
The important question is whether this medium, whatever it is, is fixed (like a plane moving through air and a boat through water) or always seems stationary in your current frame in which case you can get more energy than you put in. This wouldn't kill the idea but it would make it puzzling to only focus on the application as a better ion drive.

There comparatively straightforward drives that propose pushing against the interstellar medium (the very thin ionised gas between stars), for example http://en.wikipedia.org/wiki/Bussard_ramjet#Electrostatic_ion_scoop
Potentially these could far outperform a rocket because a rocket has to carry its own reaction mass and that gets exponentially bad. Pushing on a fixed medium would allow a mere square relationship between energy and velocity. This velocity is relative the the medium. I think I read somewhere that we are moving through the interstellar medium at about 30km/s but I couldnt find the reference.
We're spinning around the Sun at about 30km/s and the Sun is spinning around the centre of the Milky Way at about 230km/s . If you're pushing on some preferred frame that isn't geocentric then you get huge seasonal and daily variation. Even if I believed the drive worked, experimental set up still gets an F- for failing to be accurate enough to even guide theoretical work.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/01/2015 11:18 PM
To move forward commercially, you would have to either come to an agreement with him/SPR, or wait for his patents to expire, or find some way around them. I'd guess that Guido Fetta has also protected his invention as well

This is getting off topic, but that's really not something to be worried about...you can patent a specific design but you can't patent the concept.  Once the physics concept is understood, its trivial to modify the design in some way that still operates on the same basic physics principles.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Superfastjellyfish on 05/01/2015 11:32 PM


Is there a photo, drawing or block diagram of the current resonator I could see?  50W is lower than I expected to hear but that is still a large amount of power in the RF world and high power design techniques would still need to be employed.  FR4 and Teflon would both out-gas to some degree and I don't believe one is necessarily better than the other.   For either, the materials would need to be in the chamber for sufficient time to outgas enough prior to applying high power.

-JK

Not having worked much with high power RF in a vacuum I'll talk about the non-vac testing. Assuming there's some kind of corona, since the cavity is closed, wouldn't the corona be on the inside of the cavity and therefore apply equal force in both directions when the particles bounce off the other side of the cavity? The cavity is sealed so I'm not sure what amount of leakage would be needed to produce this kind of thrust, but the particles released from the surface by the corona effect should be mostly reflected internally keeping all the momentum cancelled out.

http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327937#msg1327937

According to this post, Mr. March says that 'BTW, the copper frustum is vented, so its internal pressure matches the chamber pressure after a short time period at vacuum.'

I've been drinking, but this quote seems relevant(could be only for the vac tests though.  My memory isn't what it used to be).  :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: GDIKnight on 05/01/2015 11:50 PM
Upon a cursory glance, I would like to remind everyone about certain general concepts that are overlooked:
1.  Small EM vortices constructively interfere to produce a large EM vortex, much like the funnels of a tornado feeding a large central core.  The Magnetron configuration is like the barrel of a Colt 45 revolver, generating 4 EM vortices as shown in the NASA magnetic measurements pic.  This large vortex is compressing space at the base of the vortices and expanding space at the top of the vortices.
2.  What generates radio waves, heat, and electromagnetic disturbances in nature?  A black hole.  Likewise, I believe this configuration is generating an unstable wormhole.  Literally, pulling the vehicle along while compressing space behind it.  A change in weight of the device along the direction of thrust would confirm this hypothesis if the device were to be placed upside down with the thrust pointing up.  The observation would be a lighter object contrary to gravitation physics.
3.  A secondary magnet is needed to keep the field in place.  That magnet is directing the flow of charge from the vortices.  I believe an EM torus positioned with the hole inline with the downstream would focus the flow more effectively and increase the thrust considerably.
4.  If this hypothesis pans out, I believe higher energy, larger devices at two ends of a path could generate a stable wormhole.
5.  That... And it would change how our outlook about how microwaves really work in that the heat is from the compression of space due to the formation of EM vortices... And why you should not be putting metal into a microwave.  Heehee.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/02/2015 01:24 AM

IT IS NOT THE SAME!!!!!!

Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.

Constant acceleration reactionless drive of any type violates COE.

Does a magsail?

A magsail is neither constant acceleration nor reaction-less. It is true that it does not carry its reaction mass with it but it is reacting against an external medium. But then so does a car, airplane or boat.

It is argued that the EM-drive is also reacting against an external medium, in its case the quantum vacuum.

Yes but the quantum vacuum must be Lorentz invariant. That is the quantum vacuum must look the same to all observers regardless of their inertial frame of reference. Kinda like the speed of light looks the same to all observers. Otherwise you create a special inertial frame against which you can measure absolute motion. This would be in severe conflict with relativity and just about all of modern science.

Also it creates the problem that the performance of the drive would change drastically depending on the time of year. Your state of absolute motion would differs by many miles per second over the year vastly changing the amount of power needed to operate the drive. Of course that would be one of the least problems caused by a universal frame of reference.

 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/02/2015 03:20 AM
...

Those people do not know the struggling of a scientist to get just a little more funding in their lab where only 3 or 4 other colleagues work with them. Eagleworks has an old dying RF amp and they do not even have the bucks to replace it… Paul had to build the copper frustum at home, in his wife's dining room! Really people would be shocked if they knew that....
Yes, the more crude the instrumentation, the stronger the effect.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: groundbound on 05/02/2015 04:02 AM
Commander Chris Hadfield just tweeted it to his 1.3 million followers.  :o

I have a conservation of energy question that I don't think has been asked before in any of these threads.


Where is the energy going to come from to run all the extra servers to handle this new NSF traffic??   ;D

Which leads to a more legitimate question: is there any portion of all of this discussion that makes sense to move inside the L2 bubble? Without putting any damper on the productive open threads, it would be nice to see know there is a little more revenue to offset the traffic.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Prunesquallor on 05/02/2015 04:44 AM
So let's assume the EM drive works as described and Alpha Centauri can be reached in approximately 130 earth years accounting for acceleration, cruising and  deceleration. Can anyone calculate the approximate time dilation spent? (i.e. the theory of relativity that shows  time slowing down relative to earth time and stops at light speed.) Obviously gravitational effects on time dilation would probably be impossible to factor in.

If time were slowed down enough would it allow reaching Alpha Centauri in a generation or two? Assuming one didn't die of radiation poisoning, a spec of dust piercing a hole through  them at that speed, or outright insanity.  ::)

I get around a month difference.

Yep, me too.  0.067c max velocity, t-tau=36 days for 0.001 g's.  No "cruise", just accelerate then decelerate for minimum flight time.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/02/2015 05:01 AM
So let's assume the EM drive works as described and Alpha Centauri can be reached in approximately 130 earth years accounting for acceleration, cruising and  deceleration. Can anyone calculate the approximate time dilation spent? (i.e. the theory of relativity that shows  time slowing down relative to earth time and stops at light speed.) Obviously gravitational effects on time dilation would probably be impossible to factor in.

If time were slowed down enough would it allow reaching Alpha Centauri in a generation or two? Assuming one didn't die of radiation poisoning, a spec of dust piercing a hole through  them at that speed, or outright insanity.  ::)

I get around a month difference.

Yep, me too.  v=0.067c at turnaround, t-tau = 36 days for 0.001 g's
That violates energy conservation. You're talking about way more kinetic energy than you put into it in the first place.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Prunesquallor on 05/02/2015 11:34 AM
So let's assume the EM drive works as described and Alpha Centauri can be reached in approximately 130 earth years accounting for acceleration, cruising and  deceleration. Can anyone calculate the approximate time dilation spent? (i.e. the theory of relativity that shows  time slowing down relative to earth time and stops at light speed.) Obviously gravitational effects on time dilation would probably be impossible to factor in.

If time were slowed down enough would it allow reaching Alpha Centauri in a generation or two? Assuming one didn't die of radiation poisoning, a spec of dust piercing a hole through  them at that speed, or outright insanity.  ::)

I get around a month difference.

Yep, me too.  v=0.067c at turnaround, t-tau = 36 days for 0.001 g's
That violates energy conservation. You're talking about way more kinetic energy than you put into it in the first place.

The OP qualified his question "So let's assume the EM Drive works as described..."  My response was based on that qualification.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/02/2015 12:38 PM
So let's assume the EM drive works as described and Alpha Centauri can be reached in approximately 130 earth years accounting for acceleration, cruising and  deceleration. Can anyone calculate the approximate time dilation spent? (i.e. the theory of relativity that shows  time slowing down relative to earth time and stops at light speed.) Obviously gravitational effects on time dilation would probably be impossible to factor in.

If time were slowed down enough would it allow reaching Alpha Centauri in a generation or two? Assuming one didn't die of radiation poisoning, a spec of dust piercing a hole through  them at that speed, or outright insanity.  ::)

I get around a month difference.

Yep, me too.  v=0.067c at turnaround, t-tau = 36 days for 0.001 g's
That violates energy conservation. You're talking about way more kinetic energy than you put into it in the first place.

The OP qualified his question "So let's assume the EM Drive works as described..."  My response was based on that qualification.

It is known to be impossible to violate energy conservation. Stating that it clearly does is a non-sequitur, as it implies complete knowledge of how Emdrive works (if it really does work). There is no accepted theory of operation for this thing.

For all we know, the universe might be a ginormous energy bank that you can borrow from and loan to; if you know how. You still have to balance the books at the end of the day. (pure conjecture)

I think we need to remember that until proven otherwise, this copper can is a black box. It is what it is, regardless of what some guy's theory says about it, which is likely wrong until proven correct.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tea monster on 05/02/2015 12:51 PM
The nice thing about this is that it's just a copper kettle with a magnetron attached. Any medium sized lab or even a home enthusiast could make one.

To properly evaluate it, you need a high-energy source and a vacuum chamber and proper equipment. But we aren't talking about a billion dollar research program here.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sanman on 05/02/2015 01:18 PM
So I wanted to ask...

The wave inside the resonant cavity is a standing wave, and it can exert force on the cavity itself. And in regards to its motion, that standing wave can be construed as a soliton. Ordinarily, a soliton on its own (outside of a resonant cavity) is said to be a "delicate balance of linear and nonlinear effects which counter dispersion" - but here we have a resonant cavity to counter the dispersion, with the consequence that cavity has force interaction with the trapped wave.

Is it possible that the power feed to the asymmetric cavity can somehow force the soliton to move, and thus make the cavity move with it? And thus your apparatus is then "surfing the wave"? (ie. surfing the soliton)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/02/2015 02:00 PM
So I wanted to ask...

The wave inside the resonant cavity is a standing wave, and it can exert force on the cavity itself. And in regards to its motion, that standing wave can be construed as a soliton. Ordinarily, a soliton on its own (outside of a resonant cavity) is said to be a "delicate balance of linear and nonlinear effects which counter dispersion" - but here we have a resonant cavity to counter the dispersion, with the consequence that cavity has force interaction with the trapped wave.

Is it possible that the power feed to the asymmetric cavity can somehow force the soliton to move, and thus make the cavity move with it? And thus your apparatus is then "surfing the wave"? (ie. surfing the soliton)

I'm not clear as to what effect you are referring to.  Are you referring to a Kerr-type-nonlinearity cavity soliton ?, as for example :

https://www.osapublishing.org/oe/viewmedia.cfm?uri=oe-21-7-9180&seq=0

In any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect   :)

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JackFlash on 05/02/2015 02:07 PM
Begging your pardon Dr. Rodal, but when you assert that:

 "In any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect",

I have to think that this is only necessary in order to preserve the validity of the current understanding of such things.

In any case, I'm loving what you folks are doing here. Keep chasing the data :D

Cheers
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: SH on 05/02/2015 02:17 PM
I have to think that this is only necessary in order to preserve the validity of the current understanding of such things.

While it is important to recognize that our understanding of physics is never perfectly correct and complete, you really can't mess with the basic conservation laws.  If energy or momentum is not conserved, the universe would become a completely unstable system. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sanman on 05/02/2015 03:22 PM
In any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect   :)

Alright, so the standing wave loses energy in an amount that offsets the kinetic energy gain associated with acceleration - and this is supposed to satisfy conservation of energy. And conservation of momentum is satisfied by using energy-mass equivalency?

I was just wondering what the mechanism is by which pumping up the standing wave then creates a net force on the cavity.


Here's a debunking by Greg Egan, showing why you can't have net force just because the cavity happens to be asymmetric:

http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Simple.html

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: BroncoBill on 05/02/2015 04:17 PM
What US/international laws/regulations must be satisfied to legally allow the flight of a nuclear reactor ?  Also, is it possible that the DoD X-37B is carrying such a prototype reactor ?  technology that  would need to be brought back to earth and not wilfully disposed on re-entry.  Or even a prototype thruster ? DoD timing on "Hall" thruster masking more exotic technology ?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Stormbringer on 05/02/2015 05:30 PM
actually no. It was outside critics that insisted they need to see how it performed in a vacuum chamber. :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 05/02/2015 05:35 PM
actually no. It was outside critics that insisted they need to see how it performed in a vacuum chamber. :)
From the day one, they've been performing experiments in a vacuum chamber (at ambient pressure lol).

And I always insisted on shielding it in a box.

edit: I don't think most critics even realized that the test article was un shielded and influencing the measurement apparatus (exhibit A, "baseline drift"). A sealed box in the vacuum would be the best test, a sealed box in the air second best, and without the sealed box you're just rigging an experiment to be as sensitive to as many stray classical forces as possible. Again, widely disrespected scientists (Andrea Rossi for example) are known to deliberately do similar things to get an effect.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/02/2015 06:22 PM
In any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect   :)

Alright, so the standing wave loses energy in an amount that offsets the kinetic energy gain associated with acceleration - and this is supposed to satisfy conservation of energy. And conservation of momentum is satisfied by using energy-mass equivalency?

I was just wondering what the mechanism is by which pumping up the standing wave then creates a net force on the cavity.


Here's a debunking by Greg Egan, showing why you can't have net force just because the cavity happens to be asymmetric:

http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Simple.html

Greg Egan is just showing the standing wave solution to Maxwell's equation for a truncated cone for mode shapes that have constant field in the transverse, azimuthal direction.   The solutions shown by Egan are known since the 1930's. 

That Maxwell's equations and special relativity satisfy conservation of momentum is known in general, for any problem, for any geometrical shape.  Thus, Egan is just "debunking" attempts (as done by Roger Shawyer for example or by Prof. Yang in China) trying to justify EM Drive space propulsion just using Maxwell's equations and special relativity.  Egan's paper does not and cannot debunk Dr. White's conjecture for example, or Prof. Woodward's conjecture.  Dr. White's conjecture can be objected on the grounds that it implies a mutable and degradable quantum vacuum, for example, but not solely on the grounds discussed by Egan.  Prof. Woodward's conjecture can be objected on the grounds that it needs a Wheeler–Feynman absorber theory to justify its instantaneous action from distant objects.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 05/02/2015 06:35 PM
If it doesn't work with Maxwell's equations, then it requires a violation of Maxwell's equations, and any violation above some tiny (parts per billion? trillion?) would be very detectable by it's effects on the electromagnetic fields in many practical devices. Keep in mind that 6.66 uN , which are hard to detect, correspond to 1KW worth of EM reflecting off a surface, which is hard *not* to detect.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/02/2015 06:57 PM
In any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect   :)

Alright, so the standing wave loses energy in an amount that offsets the kinetic energy gain associated with acceleration - and this is supposed to satisfy conservation of energy. And conservation of momentum is satisfied by using energy-mass equivalency?

I was just wondering what the mechanism is by which pumping up the standing wave then creates a net force on the cavity.


Here's a debunking by Greg Egan, showing why you can't have net force just because the cavity happens to be asymmetric:

http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Simple.html

Greg Egan is just showing the standing wave solution to Maxwell's equation for a truncated cone for mode shapes that have constant field in the transverse, azimuthal direction.   The solutions shown by Egan are known since the 1930's. 

That Maxwell's equations and special relativity satisfy conservation of momentum is known in general, for any problem, for any geometrical shape.  Thus, Egan is just "debunking" attempts (as done by Roger Shawyer for example or by Prof. Yang in China) trying to justify EM Drive space propulsion just using Maxwell's equations and special relativity.  Egan's paper does not and cannot debunk Dr. White's conjecture for example, or Prof. Woodward's conjecture.  Dr. White's conjecture can be objected on the grounds that it implies a mutable and degradable quantum vacuum, for example, but not solely on the grounds discussed by Egan.
Right. A lot of the handy-wavy "theoretical" justification isn't even falsifiable. Someone just makes up some other theoretical nonsense.

And the computer simulations are worse. They are based on Maxwell's Equations which literally don't allow something like the EM-drive as they conserve both momentum and energy perfectly. If you get a different result, it's either because you modified the equations that you're solving or you're just seeing an artifact of the computation.

So the theoretical work can be safely ignored.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/02/2015 07:27 PM
...

And the computer simulations ...are based on Maxwell's Equations which literally don't allow something like the EM-drive as they conserve both momentum and energy perfectly. ..
...
Yes, the COMSOL Finite Element solutions are just based on Maxwell's equations (which satisfy conservation of momentum and conservation of energy).  NASA Eagleworks performed those finite element calculations for the following reasons:

1) To calculate the natural frequencies of the truncated cone cavity, so that they know at what frequency they can excite resonance at a high Q

2) To calculate the Q for the different mode shapes

3) To calculate the different mode shapes (whether they are transverse magnetic or transverse electric modes) and the field distributions for different modes

4) To calculate the resulting temperature from induction heating by the magnetic field (those calculations compare very well with the temperatures measured by a thermal camera)

NASA Eagleworks does not use the COMSOL Finite Element analysis to calculate any thrust forces.


Of course, there is an implicit admission here by NASA Eagleworks team that any claimed interaction with the Quantum Vacuum does not have any appreciable effect on the above calculated quantities (which are solely based on Maxwell's equations).

NASA Eagleworks has not reported any force calculations (based on Maxwell's stress tensor) or Poynting vector calculations based on Maxwell's equations.  They say that they are aware that such force calculations would give zero net thrust.  This is much better than Prof. Yang's Chinese publications that report calculations for net thrust based on Maxwell's stress tensor (which does not make sense.  Therefore any such calculation reported in Prof. Yang's calculation may be due to incorrect restraining in the finite element analysis, preventing  rigid body modes, as the finite element matrix becomes singular for an unrestrained structure.)

Dr. White's calculations for the thrust are based on a separate code, which apparently he wrote based on his Quantum Vacuum theory.  I have not seen the actual formulation for this code.

Since nobody (Shawyer, Yang or NASA) had published images of the Poynting vector field for the EM Drive truncated cone I calculated the Poynting vector field, based on the exact solution of Maxwell's equations for a truncated cone (with two eigenvalue problems: one for associated Legendre functions and the other for spherical Bessel functions solved numerically) "for fun" and curiosity, to see what it looks like.  Other authors have referred to the Poynting vector.  Of course one cannot obtain a thrust of the EM Drive from the Poynting vector (for solutions of Maxwell's equations) because it flips orientation every half period, and hence it is self-cancelling. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 05/02/2015 07:38 PM
In any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect   :)

Alright, so the standing wave loses energy in an amount that offsets the kinetic energy gain associated with acceleration - and this is supposed to satisfy conservation of energy. And conservation of momentum is satisfied by using energy-mass equivalency?

I was just wondering what the mechanism is by which pumping up the standing wave then creates a net force on the cavity.


Here's a debunking by Greg Egan, showing why you can't have net force just because the cavity happens to be asymmetric:

http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Simple.html

Greg Egan is just showing the standing wave solution to Maxwell's equation for a truncated cone for mode shapes that have constant field in the transverse, azimuthal direction.   The solutions shown by Egan are known since the 1930's. 

That Maxwell's equations and special relativity satisfy conservation of momentum is known in general, for any problem, for any geometrical shape.  Thus, Egan is just "debunking" attempts (as done by Roger Shawyer for example or by Prof. Yang in China) trying to justify EM Drive space propulsion just using Maxwell's equations and special relativity.  Egan's paper does not and cannot debunk Dr. White's conjecture for example, or Prof. Woodward's conjecture.  Dr. White's conjecture can be objected on the grounds that it implies a mutable and degradable quantum vacuum, for example, but not solely on the grounds discussed by Egan.
Right. A lot of the handy-wavy "theoretical" justification isn't even falsifiable. Someone just makes up some other theoretical nonsense.

And the computer simulations are worse. They are based on Maxwell's Equations which literally don't allow something like the EM-drive as they conserve both momentum and energy perfectly. If you get a different result, it's either because you modified the equations that you're solving or you're just seeing an artifact of the computation.

So the theoretical work can be safely ignored.

I wouldn't use the words "non falsifiable"... most of so called "non-falsifiable" things start off pre-falsified by a very huge set of past experiments, but they may be sufficiently vague as to prevent concrete examples. Only a very good theory wouldn't trip up on some existing well verified data.

Let's say we have a theory where you got the force they measured on the cavity from EM waves exchanging their momentum with the cavity.

If it is claimed that this is all in accordance with Maxwell's equations, that's an algebraic error.

If it is claimed that microwaves exchange momentum with the quantum vacuum, you have a claimed deviation from Maxwell's equations which would have far reaching effects beyond some tiny forces on microwave cavities - namely the electromagnetic fields in the cavities would have to differ from those predicted by Maxwell's equations, by a huge % even when the force is very small. It is semi-plausible that nobody would notice a small force acting on enclosed resonant cavities, it is not plausible that nobody would notice the EM fields necessary to push the cavity with such force.

Any daily or seasonal variation (introduced for sake of conservation of energy given Earth's orbital motion) would be particularly bad.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Eye_one on 05/03/2015 12:02 AM
I apologize in advance my understanding is likely no where near where it should be but, there are no stupid questions only stupid people so prove me stupid.

Is it possible this device is condensing spacetime at one side and expanding it at the other creating a gravitational flow to one side?

This could explain some things like why when more power is put in the force becomes more directional or why the force changes depending on its orientation to the Earth's gravitational field.

Maybe somebody should place an atomic clock in the force it is producing.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/03/2015 05:43 AM
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2,  you loose 99% of the power.

Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.

If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Lourens on 05/03/2015 07:12 AM
Interesting stuff. Either there's something odd with these experiments, or there's something odd with the laws of physics. Without a PhD in physics I can't judge, but it does seem like an extraordinary claim, and those require extraordinary evidence, so right now my money is on an experimental artifact. Exciting though, feels like reading a Greg Egan novel :).

On the other hand, I do think we can figure out just how extraordinary the claim is using basic high school physics. Does a propellantless drive necessarily violate conservation of energy? So I went and played around a bit, and came up with this high school-level thought experiment involving a bowling ball rocket. So, for everyone else who'd like a concrete example and some numbers that anyone can understand to go with Jason's explanation, read on :).

Bowling ball rocket
A bowling ball rocket is an ordinary rocket (a mass driver), with bowling balls for fuel. These are of course high-tech aerospace grade bowling balls: they mass only 4 kg each, and they have a spring attached that is coiled up and held in that position with a bit of string. The spring on each bowling ball stores 24 J of potential energy and has no mass.

The bowling ball rocket itself has an empty mass of 8 kg, and it carries two bowling balls for fuel. It hovers in space somewhere conveniently far away from everything else, and next to it is us, wearing space suits and measuring things.

So, here's the initial situation:
m_b1 = m_b2 = 4 kg      mass of each bowling ball
m_r = 8 kg              mass of rocket
v_r = 0 m/s             velocity of rocket
v_b1 = 0 m/s            velocity of bowling ball 1
v_b2 = 0 m/s            velocity of bowling ball 2
And the energy balance looks like this

E_kin = 1/2 * m_r * v_r + 1/2 * m_b1 * v_b1 + 1/2 * m_b2 * v_b2 = 0 J
E_pot = 2 * 24 J = 48 J
E = 0 J + 48 J = 48 J

Notation note: I'm using primes in the following to denote instances of time, not derivatives.

First bowling ball
Now, the rocket uses its robot arm to place one bowling ball against the back side of its hull, with the spring touching the hull, and then it cuts the string. The spring uncoils, pushing away the bowling ball in the backward direction, and the rocket in the forward direction. All the potential energy in the spring is converted into kinetic energy.

Now, we want to know the new velocities (relative to our still stationary selves) of all the objects involved:
v_r' = ?                velocity of rocket after first bowling ball launched
v_b1' = ?               velocity of first bowling ball after launch
v_b2' = ?               velocity of second bowling ball after launch of first
Since the second ball is still on board the rocket, we know that v_b2' = v_r'. Also, this is an ordinary rocket, so energy is conserved, so the total kinetic energy of all the objects must equal the amount of energy stored in the spring. That gives us

1/2 * m_b * v_b1'^2 + 1/2 * (m_r + m_b) * v_r'^2 = 24 J

Secondly, momentum is conserved, so we have

m_b * v_b1' + (m_r + m_b) * v_r' = 0 kg*m/s

Solving these equations, we get

v_r' = 1 m/s
v_b1' = -3 m/s
v_b2' = 1 m/s

We can also calculate the kinetic energy (again relative to our stationary selves) of the various objects in the system:

E_kin_r' = 1/2 * m_r * v_r'^2 = 1/2 * 8 * 1 = 4 J
E_kin_b1' = 1/2 * m_b1 * v_b1'^2 = 1/2 * 4 * 9 = 18 J
E_kin_b2' = 1/2 * m_b2 * v_b2'^2 = 1/2 * 4 * 1 = 2 J

Also, we can calculate the momenta

p_r' = m_r * v_r' = 8 * 1 = 8 kg*m/s
p_b1' = m_b1 * v_b1' = 4 * -3 = -12 kg*m/s
p_b2 = m_b2 * v_b2' = 4 * 1 = 4 kg*m/s

Second bowling ball
Now, the rocket launches its second bowling ball. Rocket and second bowling ball together had 6J of kinetic energy, and 24J of kinetic energy is added by the spring, so the total kinetic energy of rocket and ball 2 must be 30J after the second launch:

E_kin_r'' + E_kin_b2'' = 30 J

1/2 * m_r * v_r''^2 + 1/2 * m_b2 * v_b2''^2 = 30 J

Momentum is again conserved:

m_r * v_r'' + m_b1 * v_b1'' + m_b2 * v_b2'' = 0 kg*m/s

Solving this (exercise for the reader :) ), with v_b1'' = v_b1', we get

v_r'' = 1 + sqrt(2) ~= 2.41 m/s
v_b1'' = -3 m/s
v_b2'' = 1 - 2 * sqrt(2) ~= -1.82 m/s

E_kin_r'' = 1/2 * m_r * v_r''^2 = 12 + 8 * sqrt(2) ~= 23.3 J
E_kin_b1'' = 1/2 * m_b1 * v_b1''^2 = 18 J
E_kin_b2'' = 1/2 * m_b2 * v_b2''^2 = 18 - 8*sqrt(2) ~= 6.7 J

p_r'' = m_r * v_r'' = 8 + 8*sqrt(2) ~= 19.3 kg*m/s
p_b1'' = m_b1 * v_b1'' = -12 kg*m/s
p_b2'' = m_b2 * v_b2'' = -7.3 kg*m/s

So that's an ordinary rocket, and everything works as expected.

Moving frame of reference
There's one more interesting property of this: it works from a moving frame of reference. If we had not been stationary in our space suits, but had done our measurements while moving along at 1 m/s relative to the starting speed of the rocket, then energy and momentum would still have been conserved.

In that case, we start with an initial kinetic energy of 1/2 * 16 kg * 1 m^2/s^2 = 8 J and momentum of 16 kg * -1 m/s = -16 kg*m/s (we're moving at 1 m/s relative to the rocket, so we measure the rocket moving at -1 m/s relative to us). After the first bowling ball is released, we measure velocities

v_r' = 0 m/s
v_b1' = -4 m/s
v_b2' = 0 m/s

which gives a kinetic energies

E_kin_r' = 1/2 * m_r * v_r'^2 = 1/2 * 8 * 0 = 0 J
E_kin_b1' = 1/2 * m_b1 * v_b1'^2 = 1/2 * 4 * 16 = 32 J
E_kin_b2' = 1/2 * m_b2 * v_b2'^2 = 1/2 * 4 * 0 = 0 J

The total kinetic energy is now 32 J, which equals the initial 8 J plus the 24 J contributed by the spring. Energy is conserved. For momentum we get

p_r' = m_r * v_r' = 8 * 0 = 0 kg*m/s
p_b1' = m_b1 * v_b1' = 4 * -4 = -16 kg*m/s
p_b2 = m_b2 * v_b2' = 4 * 0 = 0 kg*m/s

So the total is -16 kg*m/s, which equals what we had initially as well. Momentum is also conserved in this moving frame of reference. I'll leave the situation after the second bowling ball is launched for the reader.

Magic spring rocket
So, now let's try a propellantless rocket. We replace our aerospace grade bowling balls with magic springs. Those are just the springs from the bowling balls, still storing 24 J of energy, but now without the bowling balls attached. They have no mass whatsoever, but when they uncoil, they still push the rocket ahead.

First magic spring
So, we go back to our unmoving reference frame, reset the rocket to 0 m/s, and have it trigger its first magic spring. Assuming that the magic springs conserve energy, this converts 24 J of potential energy into 24 J of kinetic energy, which is added to the rocket. Its kinetic energy relative to us space suited observers will become

1/2 * m_r * v_r'^2 = 24 J

from which we get velocity and momentum

v_r' = sqrt(6) ~= 2.45 m/s
p_r' = m_r * v_r' = 8 * sqrt(6) ~= 19.6 kg*m/s

Now here's something odd, because momentum has not been conserved. Apparently our magic spring has transferred 19.6 kg*m/s of momentum somewhere else. If I understand the reasoning a bit, this is supposed to be taken care of by mass-energy equivalence, which requires the extended concept of momentum from Special Relativity, and is beyond the simple Newtonian physics we're using here.

Second magic spring
Now, the rocket triggers the second magic spring. This adds another 24 J of kinetic energy, for a total of 48 J, giving velocity and momentum

v_r'' = sqrt(12) ~= 3.46 m/s
p_r'' = m_r * v_r'' = 27.7 kg*m/s

There are two interesting observations here: the delta-v we got from the second magic spring is less than what we got from the first magic spring (1.01 m/s vs. 2.45 m/s). Also, the momentum change is less, 8.1 kg*m/s vs. 19.6 kg*m/s. But energy is conserved. This is one type of propellantless rocket.

Constant thrust magic spring rocket
TheTraveller claimed (http://forum.nasaspaceflight.com/index.php?topic=37438.msg1367438#msg1367438) that the EMDrive gives constant thrust at a constant power input. For the magic coil rocket, that would mean that each coil gives the same delta v. Let's see what happens with the total energy of the system if we assume that the second coil gives as much of a velocity change as the first:

v_r = 0 m/s
v_r' = sqrt(6) ~= 2.45 m/s
v_r'' = 2 * sqrt(6) ~= 4.90 m/s

E_kin = 1/2 * m_r * v_r^2 = 0 J
E_kin' = 1/2 * m_r * v_r'^2 = 24 J
E_kin'' = 1/2 * m_r * v_r''^2 = 96 J

So, here we have a situation where we put in two coils of potential energy, for a total of 48 J, but we're getting 96 J of kinetic energy back for it, at least relative to an unmoving observer. Constant acceleration, but no conservation of energy. That's a second type of propellantless rocket, and this is what ppnl is describing when (s)he says you can't have constant acceleration without violating conservation of energy.

So, which of the two types of propellantless drive is the EMDrive? According to the whitepaper linked by TheTraveller:

Quote from: http://www.emdrive.com/theorypaper9-4.pdf
Thus as the velocity of the waveguide increases in the direction of thrust, the thrust will decrease until a limiting velocity is reached when T=0.

So, apparently it's the first type. Which means that it doesn't necessarily violate conservation of energy, at least, based on Newtonian physics.

There's one more issue though. According to AdrianW (in Reply #216 (http://forum.nasaspaceflight.com/index.php?topic=37438.msg1367632#msg1367632)), while the first propellantless rocket type doesn't violate conservation of energy, it implies that it now matters from which reference frame you are measuring. So let's reset the type 1 rocket one more time, fire our suit thrusters to get us up to 1 m/s relative to the rocket, and measure the initial situation:

v_r = -1 m/s
E_kin = 1/2 * m_r * v_r^2 = 4 J
p_r = m_r * v_r = -8 kg*m/s

After the first spring, we get

v_r' = sqrt(6) - 1 ~= 1.45 m/s
E_kin' = 1/2 * m_r * v_r'^2 = 4 * (sqrt(6) - 1)^2 = 28 - 8 * sqrt(6) ~= 8.40 J
p_r' = m_r * v_r' = 8 * (sqrt(6) - 1) ~= 11.6 kg*m/s

So, from this perspective, we again lost 19.6 kg*m/s of momentum by uncoiling the first spring, but now energy isn't conserved! We get different results when measuring from different moving frames of reference! That is a violation of Galilean relativity!

This can only work if there is some very special observing velocity at which everything works out, and a rule that says that observers at other velocities need to compensate for their velocity relative to the special one. But if that is the case, then we should be measuring different values when the Earth is moving in the same direction as this special velocity, compared to six months later when it is moving in the opposite direction. Which we probably would have noticed by now.

Conclusion
So, assuming Newtonian physics, which none of the actual physicists working on this are doing of course, it appears that a propellantless rocket either violates conservation of energy, or requires one frame of reference to be special. That's a very extraordinary claim. Now if someone can explain to me how dr. White sidesteps this issue (in the simplest terms possible) I'd be much obliged :).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RotoSequence on 05/03/2015 07:31 AM
What kind of damage would a special, or preferred frame of reference do to our understanding of the cosmos?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 05/03/2015 07:55 AM
One might argue that there can't be a true inertial frame, because there is no truly field-free volume of space anywhere in the universe. Also, NASA's Marc G. Millis pointed out (sorry, no link right now) that something like inertial frames may exist, but that the origin of inertial frames remains an unknown till today.

On a side note, in case the refined EM-drive experiments unequivocally demonstrate a thrust generation, it would not demonstrate that the laws of physics are 'broken' by such a device. It would rather demonstrate that our current understanding of the physical world, as we perceive it, is 'broken'.
There is Zero chance to 'violate' anything in physics itself.. because that, which works, works. And that, which doesn't work, doesn't work. Maybe some physicists would feel 'violated' by a working EM-drive or Q-thruster.. who knows :P .

Good luck to Eagleworks (and of course Roger Shawyer).
8)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Dmytry on 05/03/2015 12:27 PM
If the forces were in nanonewton range for very high electric fields in the drive, maybe it would be just our understanding that's broken. But when you have some momentum in the double digit percentage of the total momentum being carried by the EM radiation in the cavity, that's like our communication and radar equipment that would be broken, probably our microwave ovens even, to speak nothing of more sensitive devices. You can't get such momentum to the cavity walls through microwaves without changing how microwaves are!

Everyone's so into talking about the "laws" they forget about actual observations and applications of said laws in practice, in related situations.

There's experiments dating back up to 115 years measuring the momentum that electromagnetic waves impact upon a metal surface. Notably, even the very first experiment had accuracy and repeatability far higher than "yep, looks like there may be a force".

Granted, a lot of it is not in a cavity, but that's some literal magical thinking - an individual piece of copper, an individual electron, those things don't know if they're part of cavity any more than particles of paint would know they're a part of some magical summoning pentacle. This has to be explainable in terms of elementary interactions, which we tested down to parts per trillion, tested especially well for anything involving electromagnetic waves in particular.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/03/2015 02:58 PM
What kind of damage would a special, or preferred frame of reference do to our understanding of the cosmos?

Very, very, bad not good. Because we live on the surface of a very massive body we humans instinctively think in terms of an absolute frame of reference. Even Galilean relativity is counter intuitive to us. But much of modern science depends on squeezing out that bias. Special relativity for example took Galilean relativity seriously and extended it in a new domain. 

Could Galilean relativity and ultimately special relativity be wrong? Sure, I mean it is profoundly unlikely but I'm willing to consider it. But here is the problem, Shawyer has never shown the first clue that he understands that he is violating Galilean relativity. And when it comes down to it that would be the most important part of his discovery. Launching a few satellites cheaply is small potatoes compared to what may be possible with a deeper understanding of fundamental physics. And if Shawyer's work is valid it will change fundamental physics beyond all recognition. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RonM on 05/03/2015 03:24 PM
And now we have a pretty good video, objective  (even including Sean Carroll from CalTech, and Alcubierre stating that he thinks his warp-drive concept is not practically feasible for centuries) about the NSF article on the EM Drive !

http://www.newsy.com/47123/

 :)

There is some hope for the media, as these guys got this "right", fair and balanced, respecting science and yet keeping up some hope and they put the video together in a short amount of time

I went to check local headlines this morning on ajc.com, the Atlanta Journal and Constitution newspaper website, and the newsy.com article and video was posted there this morning. Three hours after it was posted it is listed as number one on their most read article list.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Stormbringer on 05/03/2015 03:35 PM
What kind of damage would a special, or preferred frame of reference do to our understanding of the cosmos?
It would most probably slightly modify current theories. Special frames of reference are possible. At least according to new cosmological and astronomical data analysis of such things as WMAP and Plank observatory data. And there are always theories that invoke them despite the disrepute. There appears to be a preferred alignment of things in the universe like the rotational plane of the galaxies. and this evokes such things at the universe was spinning since it's inception and or dark flow and things like that. These things do lead to the dreaded preferred reference frame. If these observations prove true...

The world as we know it will not end. Theory will adjust to take it into account. It will be a special case and thus be considered as part of the trans-relativity regime. Newton was not destroyed by Einstein. We still use it. Relativity will not be destroyed by something that goes beyond it.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: vide on 05/03/2015 04:47 PM
In order for White's proposed explanation to make any sense at all, you need to assume 3 things:

(1) momentum can be stored and propagated through virtual particle pairs that are created in the vacuum fluctuations of free space.  Call this the QVP.  Obviously this is White's controversial claim, but let's entertain the idea.

(2) storing momentum int the QVP must be "difficult".  If it were easy, then momentum would be lost into the QVP all the time, from all different types of interactions, and we wouldn't observe conservation of momentum in general.  For some reason, we must accept that the situation of standing waves in a specially shaped resonant cavity is a special situation that does enable momentum transfer into the QVP.
If electromagnetic waves transfer a fraction of their own momentum to QVP that is a perturbation of the propagation of electromagnetic waves. There may be a very small experimental bound on that in resonant cavities.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/03/2015 05:09 PM
I want to openly acknowledge @TheTraveller who dropped in on the main thread to help out.

He offered fresh insight and stimulated discussion leading to progress being made today. He identified problems and offered solutions.

That kind of can do attitude is exactly what we need around here. I know an expert problem solver when I see one. Hats off to you! Hope you're here to stay.

Others dropping by should follow his example.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/03/2015 07:36 PM
Just a general comment even by the low standards of space & science reporting online it seems this particular article has suffered terribly in its wider reporting and analysis. I hope this hasn't caused any damage to the site's reputation.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: vide on 05/03/2015 07:51 PM
From another thread on this forum:
I'm sorry if this question is covered somewhere else, but is there a list of recent force plots that were posted on this forum?

Those are all the force plots I'm aware of concerning the frustum test article at Eagleworks

Source file name or figure in 2014 Brady report :
1/ Page 15, Fig 19 top
2/ Page 15, Fig 19 middle
3/ Page 15, Fig 19 bottom
4/ Page 17, Fig 21 top
5/ Page 17, Fig 21 bottom
6/ Page 18, Fig 22 Eagleworks Lab Conical Resonant Cavity Test Article Data-1, TE012 Mode_03-06-2014.jpg
7/ July 01, 2014 Copper Frustum PTFE_901.93MHz TM010 Thrust Signal in-Air.jpg
8/ March 2015 Copper Frustum 1,937.15MHz_50W_Forward_in-Air_Foam-Board Encl_Data Run.jpg
9/ Frustrum 2 energy and pressure Plus Lab Data_Polycarbonate-1_May 07, 2014.jpg
10/ Copper Kettle Data-Runs_TM212_12-12-2014A_5x10-6 Torr_50W.jpg
11/ Jan 16 2015_ Copper Frustum 1,937.188MHz in-5x10-4 Torr_35W_Reversed_Data Run-1B.jpg

Of those only the last 2 are results in vacuum

There is also
12/ Jan 2015 Copper Frustum 1,937.15MHz in-Air_50W_Forward & Reversed_Data Runs.jpg
but I'm unsure the forward data is different from one of the previous forward plots
Thank you so much. I took the liberty of uploading vacuum graphs into an album (http://temp bana/oosju).

Did the theory predict an increase in the rise/fall time constant in vacuum? If it did not, why is it not falsified by the experimental data?

Does the theory predict thrust disparity in those two graphs? If it does, why is it not falsified?

This paragraph seems very unclear to me.
Quote
The NASASpaceflight.com group has given consideration to whether the experimental measurements of thrust force were the result of an artifact. Despite considerable effort within the NASASpaceflight.com forum to dismiss the reported thrust as an artifact, the EM Drive results have yet to be falsified.
Can someone clarify what exactly would it take for "NASASpaceflight.com forum to dismiss the reported thrust as an artifact"?

Quote
After consistent reports of thrust measurements from EM Drive experiments in the US, UK, and China
In which of the competing theories was 0.7 N at 2.5kW consistent with ~78uN at 50W (linear extrapolated 14 000 uN)  ? How was this non-linear relationship (quadratic?) consistent with 54uN at 2.6W ?

What is the relation between this website ("nasaspaceflight.com") and NASA?

re: Star One, can you give me some examples?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/03/2015 07:59 PM

From another thread on this forum:
I'm sorry if this question is covered somewhere else, but is there a list of recent force plots that were posted on this forum?

Those are all the force plots I'm aware of concerning the frustum test article at Eagleworks

Source file name or figure in 2014 Brady report :
1/ Page 15, Fig 19 top
2/ Page 15, Fig 19 middle
3/ Page 15, Fig 19 bottom
4/ Page 17, Fig 21 top
5/ Page 17, Fig 21 bottom
6/ Page 18, Fig 22 Eagleworks Lab Conical Resonant Cavity Test Article Data-1, TE012 Mode_03-06-2014.jpg
7/ July 01, 2014 Copper Frustum PTFE_901.93MHz TM010 Thrust Signal in-Air.jpg
8/ March 2015 Copper Frustum 1,937.15MHz_50W_Forward_in-Air_Foam-Board Encl_Data Run.jpg
9/ Frustrum 2 energy and pressure Plus Lab Data_Polycarbonate-1_May 07, 2014.jpg
10/ Copper Kettle Data-Runs_TM212_12-12-2014A_5x10-6 Torr_50W.jpg
11/ Jan 16 2015_ Copper Frustum 1,937.188MHz in-5x10-4 Torr_35W_Reversed_Data Run-1B.jpg

Of those only the last 2 are results in vacuum

There is also
12/ Jan 2015 Copper Frustum 1,937.15MHz in-Air_50W_Forward & Reversed_Data Runs.jpg
but I'm unsure the forward data is different from one of the previous forward plots
Thank you so much. I took the liberty of uploading vacuum graphs into an album (http://temp bana/oosju).

Did the theory predict an increase in the rise/fall time constant in vacuum? If it did not, why is it not falsified by the experimental data?

Does the theory predict thrust disparity in those two graphs? If it does, why is it not falsified?

This paragraph seems very unclear to me.
Quote
The NASASpaceflight.com group has given consideration to whether the experimental measurements of thrust force were the result of an artifact. Despite considerable effort within the NASASpaceflight.com forum to dismiss the reported thrust as an artifact, the EM Drive results have yet to be falsified.
Can someone clarify what exactly would it take for "NASASpaceflight.com forum to dismiss the reported thrust as an artifact"?

Quote
After consistent reports of thrust measurements from EM Drive experiments in the US, UK, and China
In which of the competing theories was 0.7 N at 2.5kW consistent with ~78uN at 50W (linear extrapolated 14 000 uN)  ? How was this non-linear relationship (quadratic?) consistent with 54uN at 2.6W ?

What is the relation between this website ("nasaspaceflight.com") and NASA?

re: Star One, can you give me some examples?

Too many to list & I don't want to clutter this thread up with links but if you Google the terms "warp drive" or "EM" drive you'll soon get the general gist of things.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Flyby on 05/03/2015 08:05 PM
Just a general comment even by the low standards of space & science reporting online it seems this particular article has suffered terribly in its wider reporting and analysis. I hope this hasn't caused any damage to the site's reputation.
It is not so much the "low standards" but the uncontained urge for sensational reporting that usually does more damage then good.
News reporting feels compelled to scale down information to its lowest understandable form, omitting all nuances and subtleties, hence stripping it from its real content and meaning. That's how the casual "mentioning of an observation of an anomaly reported by a NASA engineer" turns into "NASA discovers Startrek-type warpdrive" in no time...
Sadly, this does way more harm then good, because it tends to discredit any research attached to the subject.

In the same category, you have those who insist in turning the EMdrive into an over-unity device. It really doesn't help for the credibility of the EMdrive. Just stay away from any of those "contaminated" topics and focus on the device, on the theoretical and practical issues of the device...

The upcoming high power test, scheduled for July (according P.March), will be the make or brake event for me as I'm still on the balance. I remain skeptical, yet I do carry the hope it turns out to be a positive test, simply because it would mean a giant leap forward for human space exploration (stationary orbital spacestations, human interplanetary travel and even interstellar probe travel).. we'll see... give it another 2-3 months......
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: arachnitect on 05/03/2015 08:11 PM

What is the relation between this website ("nasaspaceflight.com") and NASA?


No official relation.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/03/2015 09:22 PM
This may sound off the wall, but I have an idea for low cost experiments. 

Use a Crooke's Radiometer positioned adjacent to the device in the thrust direction.  Distance to the device, pane charge, temperature, pressure, polarization of light allowed through the radiometer wall, and mill pane materials are controls to be varied.  Very low mass panes should be constructed, perhaps by coating thin slivers of aerogel through vacuum metalization or other very thin layer material application processes for the emissive and aborbant sides of the pane. 

Hypothesis: If any propellant is present, to include virtual particles temporarily conferred enough energy to bring them into a non-virtual state, then it should be possible to observe radiometer motion under the right combination of conditions and materials.  The conditions and materials that achieve radiometer motion then provide insight into the nature of propellant.

I do not have the expertise to evaluate which materials and conditions should be tried, nor in which order. 

Skepticism: The mass and friction of the radiometer system must be low enough that a fraction of the thrust generated by the device is sufficient to cause rotation.  Experiments using materials with thermoelectric properties or other sophisticated materials may be required and may not be inexpensive. 

edit: To clarify, the goal in the experiments would not necessarily be to demonstrate thermal phenomena, but to adapt the operating principle of the radiometer to different interactions with the environment until the correct interaction is discovered.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Prunesquallor on 05/03/2015 10:13 PM
*snip*

I would like to remind the readers of SF of James Blish's Cities in Flight where a new space drive technology was quite simple and easy to build, but that verifying and understanding the physics of it became mankind's largest Giga project.  However this works out in the end, I don't think any of us have any certainty of how that will be.

It would be disappointing if it took a Jovian Bridge or a Lunar Pionizer to solve the physics.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KittyMoo on 05/03/2015 10:33 PM
This may sound off the wall, but I have an idea for low cost experiments. 

Use a Crooke's Radiometer positioned adjacent to the device in the thrust direction.  Distance to the device, pane charge, temperature, pressure, polarization of light allowed through the radiometer wall, and mill pane materials are controls to be varied.  Very low mass panes should be constructed, perhaps by coating thin slivers of aerogel through vacuum metalization or other very thin layer material application processes for the emissive and aborbant sides of the pane. 

Hypothesis: If any propellant is present, to include virtual particles temporarily conferred enough energy to bring them into a non-virtual state, then it should be possible to observe radiometer motion under the right combination of conditions and materials.  The conditions and materials that achieve radiometer motion then provide insight into the nature of propellant.

I do not have the expertise to evaluate which materials and conditions should be tried, nor in which order. 

Skepticism: The mass and friction of the radiometer system must be low enough that a fraction of the thrust generated by the device is sufficient to cause rotation.  Experiments using materials with thermoelectric properties or other sophisticated materials may be required and may not be inexpensive. 

edit: To clarify, the goal in the experiments would not necessarily be to demonstrate thermal phenomena, but to adapt the operating principle of the radiometer to different interactions with the environment until the correct interaction is discovered.
You do know how a Crooke's device works don't you? Why would this elucidate anything to do with an EM drive?
Maybe I am missing something though...
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/03/2015 10:45 PM

Just a general comment even by the low standards of space & science reporting online it seems this particular article has suffered terribly in its wider reporting and analysis. I hope this hasn't caused any damage to the site's reputation.
It is not so much the "low standards" but the uncontained urge for sensational reporting that usually does more damage then good.
News reporting feels compelled to scale down information to its lowest understandable form, omitting all nuances and subtleties, hence stripping it from its real content and meaning. That's how the casual "mentioning of an observation of an anomaly reported by a NASA engineer" turns into "NASA discovers Startrek-type warpdrive" in no time...
Sadly, this does way more harm then good, because it tends to discredit any research attached to the subject.

In the same category, you have those who insist in turning the EMdrive into an over-unity device. It really doesn't help for the credibility of the EMdrive. Just stay away from any of those "contaminated" topics and focus on the device, on the theoretical and practical issues of the device...

The upcoming high power test, scheduled for July (according P.March), will be the make or brake event for me as I'm still on the balance. I remain skeptical, yet I do carry the hope it turns out to be a positive test, simply because it would mean a giant leap forward for human space exploration (stationary orbital spacestations, human interplanetary travel and even interstellar probe travel).. we'll see... give it another 2-3 months......

Even if it does work there's a vast gap between that & going on holiday to the moon on a regular four hour shuttle flight. It seems as if people expect to be flying around the Solar System by next year.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: aceshigh on 05/03/2015 10:51 PM
It is known to be impossible to violate energy conservation. Stating that it clearly does is a non-sequitur, as it implies complete knowledge of how Emdrive works (if it really does work). There is no accepted theory of operation for this thing.

For all we know, the universe might be a ginormous energy bank that you can borrow from and loan to; if you know how. You still have to balance the books at the end of the day. (pure conjecture)

I think we need to remember that until proven otherwise, this copper can is a black box. It is what it is, regardless of what some guy's theory says about it, which is likely wrong until proven correct.


I just started reading a sci-fi book where they have relativistic, non FTL travel that work exactly like that. I almost thought I was reading something about the EM Drive when the author started describing it.

Starfarers, by Poul Anderson
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/03/2015 11:07 PM
This may sound off the wall, but I have an idea for low cost experiments. 

Use a Crooke's Radiometer positioned adjacent to the device in the thrust direction.  Distance to the device, pane charge, temperature, pressure, polarization of light allowed through the radiometer wall, and mill pane materials are controls to be varied.  Very low mass panes should be constructed, perhaps by coating thin slivers of aerogel through vacuum metalization or other very thin layer material application processes for the emissive and aborbant sides of the pane. 

Hypothesis: If any propellant is present, to include virtual particles temporarily conferred enough energy to bring them into a non-virtual state, then it should be possible to observe radiometer motion under the right combination of conditions and materials.  The conditions and materials that achieve radiometer motion then provide insight into the nature of propellant.

I do not have the expertise to evaluate which materials and conditions should be tried, nor in which order. 

Skepticism: The mass and friction of the radiometer system must be low enough that a fraction of the thrust generated by the device is sufficient to cause rotation.  Experiments using materials with thermoelectric properties or other sophisticated materials may be required and may not be inexpensive. 

edit: To clarify, the goal in the experiments would not necessarily be to demonstrate thermal phenomena, but to adapt the operating principle of the radiometer to different interactions with the environment until the correct interaction is discovered.
You do know how a Crooke's device works don't you? Why would this elucidate anything to do with an EM drive?
Maybe I am missing something though...

Crooke's Radiometer works by inducing a pressure difference in partial vacuum.  One side of each mill pane is engineered to be more thermal absorbent and the other to be more thermal emissive.  The gas must be at a sufficiently low pressure that thermal potential difference is possible, but sufficiently high pressure that heat radiates on the emissive side. 

I don't see why this wouldn't work via any means of creating a thermal energy differential between different sides of the panes.  Aerogel is an extraordinarily low-mass thermal insulator, and materials may be selected to convert electromagnetic energy to thermal to fulfill the operating principle in subsequent tests.  This facilitates a platform for testing of various frequencies of electromagnetic radiation, attempts at generating the thermal differential via exothermic reaction, or whatever else the more knowledgeable engineers at NASA may deem worthy of testing.

Continuing along that line of reasoning, any particles of any kind that act as a propellant must carry energy in symmetry with that presenting via thrust, if this device does not demonstrate a violation of the conservation of momentum.  Therefore, if the hypothetical propellant carries any energy in a form convertible to thermal, then it may be detected this way.  The means of detection then facilitate inference of the propellant's properties.

This may be used to eliminate possibilities. 

Personally, I'd use four high speed cameras arranged at 0 radians, pi/2, pi, and 3pi/2, with the thruster device at an angle between two of the cameras.  Then, a computer could time video recording for an effective motion framerate equal to four times that of one of the cameras (purely for motion detection purposes).  MIT has software that can detect and highlight motion imperceivable to humans. 

I'd begin with gold nanocrystals on one side of each mill pane and vacuum metalized iridium on the other side.  But then, that's just a guess off the top of my head.  If I'm correct that gold nanocrystals have significant heat conduction properties and specific heat while iridium has significant conduction properties and low specific heat, then this should work as a very sensitive thermal energy detector. 

From there, light polarization film on the outer glass enclosure of the Crooke's apparatus, various experiments with electromagnetic interference with any EM waves passing into it, and whatever other trials may suit the researchers allow for elimination of various possibilities, one by one.  Different kinds of energy tested for using a similar experimental setup provide a framework to demonstrate significance if rotation of the radiometer is achieved.

But like I said earlier, it's a very old tool with a few tweaks in this idea.  There are explanations for the thrust that would not be detected this way.

Another useful experiment would be to point two of these devices' thrust direction at each other to see if the principal of propulsion can even interact with itself.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: vulture4 on 05/03/2015 11:16 PM
...

Those people do not know the struggling of a scientist to get just a little more funding in their lab where only 3 or 4 other colleagues work with them. Eagleworks has an old dying RF amp and they do not even have the bucks to replace it… Paul had to build the copper frustum at home, in his wife's dining room! Really people would be shocked if they knew that....
Yes, the more crude the instrumentation, the stronger the effect.
I also do basic research at a NASA center and I agree that even the most meager resources are extremely hard to come by. I had to personally buy a lot of our equipment on E-bay with money I made working weekends at a second job. I strongly feel that all NASA centers should have a substantial budget for internally selected research projects. Our nation is falling behind in basic research. Unfortunately it requires at least modest taxpayer funding, and the NASA budget is flat, and every dollar is spoken for. NASA's viewpoint is they give you a little seed money and in less than a year you have to turn your idea into something venture capitalists will be fighting to finance. Not so easy when you are trying to understand basic science. I'd be happy to see this project better financed, and certainly to see a physicist added to the team,  but there are many other deserving projects that are rejected or abandoned every year without notice but aren't talked about much because they are not as controversial.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KittyMoo on 05/03/2015 11:16 PM
But a Crooke's device will rotate even in a uniform radiation field, even your fancy variant.
I am not clear how it could be used to test an EM drive, which doesn't emit any photons in a preferred direction.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Prunesquallor on 05/03/2015 11:23 PM

Even if it does work there's a vast gap between that & going on holiday to the moon on a regular four hour shuttle flight. It seems as if people expect to be flying around the Solar System by next year.

NASA is an applied research organization. To justify spending any resources on this, a space flight application is needed. I don't see a problem with pointing out potential applications if they fall within postulated performance. Yes, there are many unknowns about the emdrive's practical performance given it works at all. But if it just a laboratory curiosity, NASA is the wrong group to be working on it.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/03/2015 11:27 PM
But a Crooke's device will rotate even in a uniform radiation field, even your fancy variant.
I am not clear how it could be used to test an EM drive, which doesn't emit any photons in a preferred direction.

It doesn't emit EM radiation that has been detected so far.  That does not mean that every possible mode of energy transference to ... something ... has been eliminated. 

The experiment would need to be calibrated by measuring rotation caused by ambient energy, or (better yet) such rotation could be eliminated completely if at all possible.  But if there is any way to convert whatever comes from the back of that thing into thermal energy then there is some way to have it affect the rotation of the radiometer.  And if thermal energy is transmitted across space, then the energy can be measured to establish conservation of momentum.

The benefit of these experiments is that they can eliminate possibilities at low cost. 

The only three things I can think of that would not at all be detectable this way are gravity, extraordinarily short-lived virtual particles, or some means by which a microwave is split such that one interacts with the other. 

For the virtual particle possibility, I'd suggest tapping these people:

http://scitation.aip.org/content/aip/journal/apl/98/23/10.1063/1.3597793. 

For the gravity possibility, I'd suggest eliminating every other possibility, even if it involves some blind alley testing.  For the microwave self-interference (correct term?) possibility, I'd suggest using two of these devices in an attempt to elicit an interaction between them such that detectable radiation indicating the effect results.

edit: To be clear, the radiometer idea may seem crazy, but it's an attempt to come up with a very low cost means of experimentation. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KittyMoo on 05/03/2015 11:34 PM
You make good and fair points.
I just disagree that it is worthwhile for EM drive experiments.
Probably no harm in trying, but I just can't see it myself.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/03/2015 11:38 PM
To be fair, I wouldn't be surprised if I'm flat out wrong.  It's just the next step I'd take.  Studying and debating theory only gets one so far when it seems that the theory doesn't suffice.  Sometimes, it's necessary to bang rocks together.  :D 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: vulture4 on 05/03/2015 11:47 PM
"It doesn't emit EM radiation that has been detected so far. "  The resonator in the NASA reports clearly emits EM radiation in the infrared band, and in an asymmetrical manner. IR radiation produces a recoil force and is now believed to be responsible for the anomalous acceleration of the Pioneer probes.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KittyMoo on 05/03/2015 11:55 PM
"It doesn't emit EM radiation that has been detected so far. "  The resonator in the NASA reports clearly emits EM radiation in the infrared band, and in an asymmetrical manner. IR radiation produces a recoil force and is now believed to be responsible for the anomalous acceleration of the Pioneer probes.
That would make it a photon rocket which the EM device clearly is not... Read the main thread for analysis of this.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/04/2015 01:12 AM
I must agree with a FAQ suggestion I saw from the main thread at this point.  It's not a trivial task to compile it, but perhaps instead a topic index with brief synopses and links would suffice if a sufficiently qualified person can identify worthy posts. 

This kind of thing excites people who have a passion for science because in an open question, it's feasible that a nudge in the right direction can come from anywhere.  This is also an important enough topic that it can clearly be used to spur public interest in NASA and interest in related topics.  But the discussion needs a framework that's approachable from an interdisciplinary perspective. 

After that point, reference material might be discussed to assist those of us running to catch up.  After the vacuum test, it appears to be likely that this will be an increasingly popular topic with time, and that calls for preparation.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Collapsar on 05/04/2015 01:52 AM
Before we gets lots of questions about terrestrial applications.

Quote
18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

http://emdrive.com/faq.html

Maybe this is a stupid question, but if thrust drops off rapidly when used to accelerate the vehicle along the thrust vector, how can it be useful for interstellar travel?  You would be wanting to accelerate the vehicle in the same direction of the thrust for a long period of time (toward the target star system).  I can only imagine that it would be useful for lifting payloads to a certain altitude, or repositioning from LEO to GEO.  Watching the Shawyer Youtube videos, he even says that a propellant is needed to get up to orbital velocity once the altitude is achieved.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ragingrei on 05/04/2015 02:16 AM
Question from a layman... if the EM Drive works as described, would there be a force against whatever is behind it?

For example, a helicopter causes a lot of wind beneath the blades and displaces dust. Would an EM Drive do the same?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ChrisWilson68 on 05/04/2015 02:33 AM
Question from a layman... if the EM Drive works as described, would there be a force against whatever is behind it?

For example, a helicopter causes a lot of wind beneath the blades and displaces dust. Would an EM Drive do the same?

That's kind of like asking if a Unicorn existed what it's horn would be made of.

There are different proposed theories for what might cause an EM Drive to work, if it did work.  Some people think all the proposed theories are likely wrong, even if it does work.

This is like people speculating about what the canals of Mars were made from, back during the craze when so many people thought they saw canals at the fringe of detectability through their telescopes.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 02:41 AM
Before we gets lots of questions about terrestrial applications.

Quote
18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

http://emdrive.com/faq.html

Maybe this is a stupid question, but if thrust drops off rapidly when used to accelerate the vehicle along the thrust vector, how can it be useful for interstellar travel?  You would be wanting to accelerate the vehicle in the same direction of the thrust for a long period of time (toward the target star system).  I can only imagine that it would be useful for lifting payloads to a certain altitude, or repositioning from LEO to GEO.  Watching the Shawyer Youtube videos, he even says that a propellant is needed to get up to orbital velocity once the altitude is achieved.

Yeah, think it on through. Forget interstellar, think of the power difference required to move east rather than west on the earth. Due to the rotation of the planet you are traveling at 1000 mph to the east. Trying to go that way would be like hitting a brick wall. But it gets worse. The earth orbits the sun at 66000 mph so trying to go up at the wrong time of day would be far worse.

The device makes no sense as stated.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KelvinZero on 05/04/2015 02:45 AM
Maybe this is a stupid question, but if thrust drops off rapidly when used to accelerate the vehicle along the thrust vector, how can it be useful for interstellar travel?  You would be wanting to accelerate the vehicle in the same direction of the thrust for a long period of time (toward the target star system).  I can only imagine that it would be useful for lifting payloads to a certain altitude, or repositioning from LEO to GEO.  Watching the Shawyer Youtube videos, he even says that a propellant is needed to get up to orbital velocity once the altitude is achieved.
Obeying conservation of energy could still give you a 'velocity proportional to kinetic energy squared' relationship, which is what they are trying to claim here. This is still vastly better than the exponential relationship between propellent and velocity that you get from the rocket equation.

The problem is that they are glossing over that in the case where energy is conserved there appears to have to be a particular frame of reference, such as the air that a plane moves through. They sort of imply you are always stationary wrt to this frame of reference at the moment you turn the machine on. In this case energy you can get more energy than you put in by continually turning the machine off and on.. but it is not really clear what is being claimed which to me is the most significant problem by far. Without a clear claim there is no way to falsify it.

My impression is that the original theory that lead to the experiment has been found in error, but experimenters still feel they found an effect, though the reason for such an effect is now up in the air. It is the lack of one specific theory that makes it very hard to distinguish effect from artefact.

Science is often willing to invest far more, and make conclusions on the basis of far more sensitive phenomena than what is claimed here. Consider the multibillion dollar searches for new particles that only occasionally collide with supercooled detectors far below the surface to avoid cosmic rays (or perhaps it is colliders that get the big bucks, it doesnt matter). The difference is that these are testing very well defined theories, so it is far easier to discard anomalous values as not proof of a specific claim. In those tests getting a result a thousand times stronger than you predicted is not lauded as a step forwards, it is time to rip out your hair, retest all your equipment and finally rip up your theory and try to think of another one. :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ragingrei on 05/04/2015 03:01 AM
Question from a layman... if the EM Drive works as described, would there be a force against whatever is behind it?

For example, a helicopter causes a lot of wind beneath the blades and displaces dust. Would an EM Drive do the same?

That's kind of like asking if a Unicorn existed what it's horn would be made of.

There are different proposed theories for what might cause an EM Drive to work, if it did work.  Some people think all the proposed theories are likely wrong, even if it does work.

This is like people speculating about what the canals of Mars were made from, back during the craze when so many people thought they saw canals at the fringe of detectability through their telescopes.

Correct me if I'm wrong, but those don't sound like very pertinent analogies.

It seems reasonable to suppose that if they were able to measure some thrust, then they might have measured or might be able to surmise what effects are observed nearby.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WarpTech on 05/04/2015 03:55 AM
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2,  you loose 99% of the power.

Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.

If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.

I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;

As a waveguide, the group velocity is something like;

v_g = c x sqrt(1 - (c/2d*f)^2)

Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.

c/2d = fc,  is the Low cut-off frequency of the waveguide.

The refractive index depends on the Low cut-off frequency as a function of the diameter,

K = 1/sqrt( 1 - (fc/f)^2)

For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.

There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.

Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.

Here is how it conserves momentum;

In the PV Model, momentum transforms as,

p => p*sqrt(K)

In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity. 

However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.

The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.

That’s IMHO as an engineer of course. Any comments?

See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering

Todd D.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 04:14 AM
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2,  you loose 99% of the power.

Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.

If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.

I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;

As a waveguide, the group velocity is something like;

v_g = c x sqrt(1 - (c/2d*f)^2)

Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.

c/2d = fc,  is the Low cut-off frequency of the waveguide.

The refractive index depends on the Low cut-off frequency as a function of the diameter,

K = 1/sqrt( 1 - (fc/f)^2)

For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.

There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.

Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.

Here is how it conserves momentum;

In the PV Model, momentum transforms as,

p => p*sqrt(K)

In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity. 

However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.

The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.

That’s IMHO as an engineer of course. Any comments?

See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering

Todd D.

In what sense does this conserve momentum?

Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WarpTech on 05/04/2015 04:46 AM
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2,  you loose 99% of the power.

Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.

If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.

I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;

As a waveguide, the group velocity is something like;

v_g = c x sqrt(1 - (c/2d*f)^2)

Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.

c/2d = fc,  is the Low cut-off frequency of the waveguide.

The refractive index depends on the Low cut-off frequency as a function of the diameter,

K = 1/sqrt( 1 - (fc/f)^2)

For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.

There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.

Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.

Here is how it conserves momentum;

In the PV Model, momentum transforms as,

p => p*sqrt(K)

In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity. 

However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.

The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.

That’s IMHO as an engineer of course. Any comments?

See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space
_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering

Todd D.

In what sense does this conserve momentum?

Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.

When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.

(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,

p => p*sqrt(K)

THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.


Regards,
Todd D.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 05:04 AM
Gravity certainly conserves momentum.

When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

Did you really think that orbital mechanics did not conserve momentum? 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WarpTech on 05/04/2015 05:19 AM
<snip>

In what sense does this conserve momentum?

Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.

When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.

(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,

p => p*sqrt(K)

THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.


Regards,
Todd D.

Gravity certainly conserves momentum.

When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

Did you really think that orbital mechanics did not conserve momentum?

You are referring to Newtonian gravity. I'm referring to a form of GR, where it is the curvature of the manifold intersecting the object that causes it to fall, not some "action at a distance" or exchange of gravitons. In this case, that curvature is simply the gradient in the refractive index. Inside the cone, photons are moving in a variable refractive index. This causes red & blue shift and an imbalance in momentum. This is exactly what the Earth does to the vacuum surrounding it, it filters field modes and that causes the refractive index to increase. The cone is like the falling object, falling relative to the imbalance in the internal momentum which is the curved manifold.

I agree, this is not standard GR, it is certainly not accepted physics. It is based on my own understanding of the Polarizable Vacuum Model of GR which I referenced earlier, as well as the Quantum Vacuum by Milonni, and my own work. Which predicted some 10 years ago, that it is easier to mimic gravity in over a limited bandwidth, than it is to create artificial gravity that affects all frequencies of light and matter.

Todd D.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 05:41 AM
<snip>

In what sense does this conserve momentum?

Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.

When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.

(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,

p => p*sqrt(K)

THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.


Regards,
Todd D.

Gravity certainly conserves momentum.

When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

Did you really think that orbital mechanics did not conserve momentum?

You are referring to Newtonian gravity. I'm referring to a form of GR, where it is the curvature of the manifold intersecting the object that causes it to fall, not some "action at a distance" or exchange of gravitons. In this case, that curvature is simply the gradient in the refractive index. Inside the cone, photons are moving in a variable refractive index. This causes red & blue shift and an imbalance in momentum. This is exactly what the Earth does to the vacuum surrounding it, it filters field modes and that causes the refractive index to increase. The cone is like the falling object, falling relative to the imbalance in the internal momentum which is the curved manifold.

I agree, this is not standard GR, it is certainly not accepted physics. It is based on my own understanding of the Polarizable Vacuum Model of GR which I referenced earlier, as well as the Quantum Vacuum by Milonni, and my own work. Which predicted some 10 years ago, that it is easier to mimic gravity in over a limited bandwidth, than it is to create artificial gravity that affects all frequencies of light and matter.

Todd D.

Sorry dude but that's just word salad. Momentum cannot "imbalance", GR is simply not relevant and if you have a black box that has gained momentum then you have to point to another object that has equal momentum in the other direction or you have violated conservation of momentum. By definition. If your version of GR allows this then your version of GR violates conservation of momentum.

I suggest we move on.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: geza on 05/04/2015 11:30 AM
EM drive is a very clear case of pseudoscience. Not because it contradicts physics, as we know it. Questioning current science is a normal scientific endeavour - provided that the questioner knows what he/she is doing. It is pseudoscience because of the double-talk about acceptance, or non-acceptance, of the "usual" physics.

Chris' article explains that the EM drive supposedly exchanges momentum with the so called "Quantum Vacuum". The well-established physics knows absolutely nothing about this possibility. That is, they propose existence of a completely new physical phenomenon, which may, or may not exist. (Probably not.) However, look this site:
http://emdrive.com/principle.html
Here they explain EM drive without the slightest mention of the revolution they propose in physics. The attached theory paper makes specific calculations about the operation of the drive, apparently on the basis of the usual physics. Again, there is no mention of a momentum exchange with the "Quantum Vacuum". Chris' paper mentions also a "new computational code that models the EM Drive’s thrust". Again, this implies that their thinking is based on a known theory, instead of some speculation about a currently unknown phenomenon.

So, do they revolutionize physics? Or, they just apply the existing ones? In the first case, how can they make calculations without developing the quantum theory of their alleged momentum exchange to "Quantum Vacuum"? There is no such thing in their their theory paper. In the second case, momentum conservation prohibits EM drive to work and they calculations must be wrong. Momentum conservation is not something optional: Within the framework of the known quantum physics, momentum conservation is a direct consequence of translation invariance. You cannot tamper it without questioning the very basics of quantum physics.

It is pseudoscience.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: TheTraveller on 05/04/2015 11:38 AM
EM drive is a very clear case of pseudoscience. Not because it contradicts physics, as we know it. Questioning current science is a normal scientific endeavour - provided that the questioner knows what he/she is doing. It is pseudoscience because of the double-talk about acceptance, or non-acceptance, of the "usual" physics.

Chris' article explains that the EM drive supposedly exchanges momentum with the so called "Quantum Vacuum". The well-established physics knows absolutely nothing about this possibility. That is, they propose existence of a completely new physical phenomenon, which may, or may not exist. (Probably not.) However, look this site:
http://emdrive.com/principle.html
Here they explain EM drive without the slightest mention of the revolution they propose in physics. The attached theory paper makes specific calculations about the operation of the drive, apparently on the basis of the usual physics. Again, there is no mention of a momentum exchange with the "Quantum Vacuum". Chris' paper mentions also a "new computational code that models the EM Drive’s thrust". Again, this implies that their thinking is based on a known theory, instead of some speculation about a currently unknown phenomenon.

So, do they revolutionize physics? Or, they just apply the existing ones? In the first case, how can they make calculations without developing the quantum theory of their alleged momentum exchange to "Quantum Vacuum"? There is no such thing in their their theory paper. In the second case, momentum conservation prohibits EM drive to work and they calculations must be wrong. Momentum conservation is not something optional: Within the framework of the known quantum physics, momentum conservation is a direct consequence of translation invariance. You cannot tamper it without questioning the very basics of quantum physics.

It is pseudoscience.
Use of the QV as a momentum dump is a idea from Dr. White of Eagleworks (a part of NASA).

Roger Shawyer, inventor of the EM Drive, claims there is no need for the QV and it is not involved.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/04/2015 11:48 AM
EM drive is a very clear case of pseudoscience. Not because it contradicts physics, as we know it. Questioning current science is a normal scientific endeavour - provided that the questioner knows what he/she is doing. It is pseudoscience because of the double-talk about acceptance, or non-acceptance, of the "usual" physics.

Chris' article explains that the EM drive supposedly exchanges momentum with the so called "Quantum Vacuum". The well-established physics knows absolutely nothing about this possibility. That is, they propose existence of a completely new physical phenomenon, which may, or may not exist. (Probably not.) However, look this site:
http://emdrive.com/principle.html
Here they explain EM drive without the slightest mention of the revolution they propose in physics. The attached theory paper makes specific calculations about the operation of the drive, apparently on the basis of the usual physics. Again, there is no mention of a momentum exchange with the "Quantum Vacuum". Chris' paper mentions also a "new computational code that models the EM Drive’s thrust". Again, this implies that their thinking is based on a known theory, instead of some speculation about a currently unknown phenomenon.

So, do they revolutionize physics? Or, they just apply the existing ones? In the first case, how can they make calculations without developing the quantum theory of their alleged momentum exchange to "Quantum Vacuum"? There is no such thing in their their theory paper. In the second case, momentum conservation prohibits EM drive to work and they calculations must be wrong. Momentum conservation is not something optional: Within the framework of the known quantum physics, momentum conservation is a direct consequence of translation invariance. You cannot tamper it without questioning the very basics of quantum physics.

It is pseudoscience.

Casimir momentum is old news:

Here's some lectures to read. Make sure you follow up with the rest of the supporting materials going back 60+ years.

http://qvg2013.sciencesconf.org/conference/qvg2013/program/Donaire_qvg2013.pdf
http://www.iesc-proceedings.org/articles/iesc/pdf/2012/01/iesc_qed2012_02004.pdf

In case the above links don't work:
https://drive.google.com/folderview?id=0B4PCfHCM1KYoTXhSUTd5ZDN2WnM&usp=sharing

I'm so sick of all this handwaving. Hit the books!

Challenge your preconceptions, or they will challenge you. - Velik
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: geza on 05/04/2015 11:54 AM
Casimir effect is, of course, old news. It does not carry momentum away. Moreover, the theory paper on EM drive does NOT mention and/or take into account Casimir effect in the calculation.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/04/2015 11:56 AM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: geza on 05/04/2015 12:10 PM
This thrust should not exist according to physics, as we know it. An unquestionable experimental result would mean a scientific revolution. Still, people who allegedly measure this force calculate it as if it were a consequence of known physics. Something is wrong here.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/04/2015 01:04 PM
... Something is wrong here.
Notwithstanding the known-objections to the proposed theoretical explanations (already pointed out in the article), the challenge has been to show whether the measurements are an experimental artifact or whether there is anything useful here for space propulsion.

Here is an experimental artifact explanation that I proposed:

https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT

Can you offer alternative explanations for the experimental measurements in the US, UK and China?

Thanks
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: alexterrell on 05/04/2015 02:46 PM
Page 21 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011213.pdf

Thanks for the answer Chris. My applogies, I should have been more specific, I meant the one that's labled 'Warpstar 1' and looks (probably more accurately) like the main cabin of the Fireball XL5. Sorry for the confusion.
The picture of "Warpstar 1"

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=782189;image)

was posted by Paul March (an engineer at NASA Eagleworks) in the EM Drive thread

see: https://forum.nasaspaceflight.com/index.php?topic=36313.msg1331771#msg1331771

In his own words:

Quote
I have no doubt now that this quantum vacuum derived propulsion system will be able to meet and ultimately surpass my conjectured WarpStar-I concept vehicle performance that I wrote about in my STAIF-2007 paper based on Woodward's Mach Lorentz Thrusters (MLT) of the day.  A vehicle that could go from the surface of the Earth to the surface of the Moon with a crew of two and six passengers with luggage in under four hours and then return to the surface of the Earth in another 4 hours with the same payload using just one load of H2/O2 fuel cell derived electrical power assuming 500-to-1,000 N/kWe efficiency MLTs or Q-Thrusters.  And yes, I know that's a mighty big leap from the 1.0uN/Watt we currently have demonstrated at the Eagleworks Lab, but if Dr. White's QVF/MHD conjecture is anywhere close to reality, it will be doable, at least in the long term.

Best, Paul M.

Note that Paul's statement

" I know that's a mighty big leap from the 1.0uN/Watt we currently have demonstrated at the Eagleworks Lab"

refers to the measured force in a vacuum per input electric power at NASA Eagleworks.  The highest measured force per input power was 1 Newton/kiloWatt for the experiments by Prof. Yang in China with a non-superconducting truncated cone EM Drive and by Cannae LLC in the USA for their superconducting EM Drive shaped like a pillbox.

Just going through this information. I ignored the thread for several months thinking it was nonsense, but obviously it's worth looking at in more detail. If it it true, then it could be the biggest breakthrough since the man made motion from heat (I guess the steam engine).

However, I remain sceptical - and this doesn't help (sorry if this is dissected elsewhere):
- 28 tons to the moon, assuming 60MJ/kg (100% efficient) requires 1.68E12 Joules
- Enthalpy of formation of water = 285KJ/mol = 15.83E9 J/ton
- Assuming 100% chemical to Gravitational energy, we need 1.68E12/15.83E9 tons = 106 tons. ONE WAY.

So the vehicle above breaks the laws of conservation of energy and could be used as a perpetual motion machine.

I can accept an incredible static thrust level, but not a breaking of this law.

The figure of 1W providing 30N implies that the reaction mass, whatever it is, is moving at 2m/s. That's a very slow exhaust.

To not break laws, Energy In > Delta GPE + Delta Kinetic Energy. No chemical reaction can lift itself to orbit (about 30MJ/kg) (ie without dumping the reactant).

However, you might be able to take a ballistic missile submarine, replace the missiles with this drive, and put your nuclear submarine in orbit - over the course of a few weeks (and ignoring the fact that the reactor won't work without cooling water).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Flyby on 05/04/2015 03:24 PM
EM drive is a very clear case of pseudoscience. ..................................
.................
It is pseudoscience.

Personally, I'd wait till begin July, when Eagleworks perform their high power test, before making any such bold statements. It is not because theoretical physicists and aeronautic engineers are unable to formulate a coherent theory on something that might or might not work that it doesn't carry any value.

With such an attitude of dismissal, scientific research would simply get no where.
Curiosity and investigation are the key elements for science, so... until the experiments are validated (positively or negatively) by several different parties, in a scientific manner, there is currently absolutely nothing substantial to be said, except for personal opinions and theories that address the "why?" question.

At this stage, there is no flawless proof for it to work, but neither has it been disproved.
The only real constructive discussions are those that concerns possible flaws and shortcomings in current and past experiments, as they help to improve the next tests...
The end goal is to assess whether or not the experiment shows enough scientific evidence for a definitive conclusion.

Dismissing it without hard evidence does not help...
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 03:28 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: kch on 05/04/2015 03:41 PM

This thrust should not exist according to physics, as we know it.

That's the point -- there are still (at least a few) things we don't know.



An unquestionable experimental result would mean a scientific revolution.

It very well might.  They do happen (occasionally) ... :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/04/2015 03:52 PM
1) if I put 50 watts into the drive and can't account for where even 1 micro watt goes, you can't just say it disappears. If it goes into work in the form of motive force, I don't see the violation here.

2) here are some tests by Eagleworks and the thrust per watt.

A) 1932.6 MHz 5.4 uN/W
 B) 1936.7 MHz 3.0 uN/W
C) 1880.4 MHz 21.3 uN/W
D) 2168 MHz no thrust detected, cause thought to be the lack of the dielectric resonator.

And the China tests at 2.45 (2.457 seemed to be peak) with a dirty source and they got a lot of thrust as well.

There is something known that could explain why A produced more thrust than B. It would also explain why D failed to produce thrust, resonator not withstanding, while the others did. It would also in my mind validate Dr. White's theory, or at least show he is going in the right direction.

I'll go into detail after Star-Drive's next log in just incase he would like me to keep my big fat mouth shut.  :)




Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/04/2015 05:05 PM
For those interested this has now reached the hallowed halls of Forbes who have taken an understandable very cautious approach. Actually  the article could be interpreted as yet another in the line of it sounds too good to be true.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/04/2015 05:31 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?

Nothing. Momentum from nothing.

There is actually real science here. You have to let go of your preconceptions first, and only stick to the facts.

https://www.google.com/search?q=momentum+from+nothing&ie=utf-8&oe=utf-8

And a post I put together about the history of this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1358659#msg1358659

I need you to acknowledge what you know to be fact, and embrace what you don't know. Let any emotional attachment to your worldview go, and you'll find the truth.

All of these experimentalist are telling us they're seeing an anomaly. They can't all be idiots. Nature is telling us something. Listen.
http://physicsandphysicists.blogspot.it/2012/05/what-does-it-mean-to-be-experimentalist.html
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 05/04/2015 05:34 PM
(I see the original post was deleted by the person making it.....but the below still stands).

Some of these big "general interest" sites only want your clicks for their mass of advertisers, so basically one is patting them on the back by linking them. I always felt linking is not unlike liking. I know it'll always happen, but I don't think (X mass media site) will lose any sleep over criticism of their articles. I would also point out that big sites that are late to the game (as they are) tend to use an armwavey attitude via being upset they missed the boat on the considerable interest (both for and against) on this news. I assume that is the case before even reading it.

As far as bad reporting of content on this site, nothing we can do about that. They did link the article, so anyone who doesn't click through and read our article is doing themselves a disservice.

Moving on.....

PS A writer with a big site has got in touch and clearly is on the right side of the media, so we'll help him! :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/04/2015 05:49 PM
That's good to hear Chris. Surely that's what reporters should be doing speaking to the original sources but then maybe I'm naive in the way these things work.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tchernik on 05/04/2015 06:29 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?

Nothing. Momentum from nothing.

There is actually real science here. You have to let go of your preconceptions first, and only stick to the facts.

https://www.google.com/search?q=momentum+from+nothing&ie=utf-8&oe=utf-8

And a post I put together about the history of this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1358659#msg1358659

I need you to acknowledge what you know to be fact, and embrace what you don't know. Let any emotional attachment to your worldview go, and you'll find the truth.

All of these experimentalist are telling us they're seeing an anomaly. They can't all be idiots. Nature is telling us something. Listen.
http://physicsandphysicists.blogspot.it/2012/05/what-does-it-mean-to-be-experimentalist.html

As Feynman said:

Quote
Nature is going to come out the way she is

Let the experiments do the talking, become your own worst critic, and find the truth regardless if that inconveniences some or most people's preconceptions. Including yours.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 06:33 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?

Nothing. Momentum from nothing.

There is actually real science here. You have to let go of your preconceptions first, and only stick to the facts.

https://www.google.com/search?q=momentum+from+nothing&ie=utf-8&oe=utf-8

And a post I put together about the history of this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1358659#msg1358659

I need you to acknowledge what you know to be fact, and embrace what you don't know. Let any emotional attachment to your worldview go, and you'll find the truth.

All of these experimentalist are telling us they're seeing an anomaly. They can't all be idiots. Nature is telling us something. Listen.
http://physicsandphysicists.blogspot.it/2012/05/what-does-it-mean-to-be-experimentalist.html

Well as long as you understand that you are getting momentum from nothing then fine. I have no problem with oddball theories as long as you follow the logic all the way through. I'm not getting how this can be called a sail but whatever. You are also in stark disagreement with Shawyer here. That isn't a bad thing as I actually agree with you. The problem is Shawyer is wrong in a very simple and obvious way. That utterly destroys any confidence that he is competent to be involved at all. There are still the other tests but they have their own problems with frame dependence and such that they need to address.

And as for my emotional attachment to my "world view" I'm sorry but that's crap. I only note that COM, COE and frame independence are very useful principles and violating them is extremely problematical. If you can do it then my hats off to you but until then my Bayesian priors are elsewhere to say the least.

This idea of "emotional attachment" often comes up in fringe subjects. From bigfoot and UFOs to cold fusion the claim is made that people are only protecting the status quo because they have so much invested in it. Emotionally, professionally, financially they are committed. This argument rarely works out. Proponents of cold fusion for example charged that there was a "hot fusion mafia" actively opposing cold fusion research. How did that work out for them? I will leave bigfoot and UFOs for you to ponder.

I could offer the counter proposition that people are emotionally drawn to these kinds of hopeful theories. Christians who are sure the second coming is just around the corner. Spiritualists who believe in ghosts and a rich rewarding afterlife. UFO buffs with "I want to believe" t-shirts. And yes space buffs who would really like to have a reactionless drive. Me? I have a lotto ticket that I'm sure has a good chance this week. I think history is much kinder to this proposition than it is to yours.




 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: aceshigh on 05/04/2015 06:34 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?

the luminiferous aether? :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tchernik on 05/04/2015 06:49 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?

Nothing. Momentum from nothing.

There is actually real science here. You have to let go of your preconceptions first, and only stick to the facts.

https://www.google.com/search?q=momentum+from+nothing&ie=utf-8&oe=utf-8

And a post I put together about the history of this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1358659#msg1358659

I need you to acknowledge what you know to be fact, and embrace what you don't know. Let any emotional attachment to your worldview go, and you'll find the truth.

All of these experimentalist are telling us they're seeing an anomaly. They can't all be idiots. Nature is telling us something. Listen.
http://physicsandphysicists.blogspot.it/2012/05/what-does-it-mean-to-be-experimentalist.html

Well as long as you understand that you are getting momentum from nothing then fine. I have no problem with oddball theories as long as you follow the logic all the way through. I'm not getting how this can be called a sail but whatever. You are also in stark disagreement with Shawyer here. That isn't a bad thing as I actually agree with you. The problem is Shawyer is wrong in a very simple and obvious way. That utterly destroys any confidence that he is competent to be involved at all. There are still the other tests but they have their own problems with frame dependence and such that they need to address.

And as for my emotional attachment to my "world view" I'm sorry but that's crap. I only note that COM, COE and frame independence are very useful principles and violating them is extremely problematical. If you can do it then my hats off to you but until then my Bayesian priors are elsewhere to say the least.

This idea of "emotional attachment" often comes up in fringe subjects. From bigfoot and UFOs to cold fusion the claim is made that people are only protecting the status quo because they have so much invested in it. Emotionally, professionally, financially they are committed. This argument rarely works out. Proponents of cold fusion for example charged that there was a "hot fusion mafia" actively opposing cold fusion research. How did that work out for them? I will leave bigfoot and UFOs for you to ponder.

I could offer the counter proposition that people are emotionally drawn to these kinds of hopeful theories. Christians who are sure the second coming is just around the corner. Spiritualists who believe in ghosts and a rich rewarding afterlife. UFO buffs with "I want to believe" t-shirts. And yes space buffs who would really like to have a reactionless drive. Me? I have a lotto ticket that I'm sure has a good chance this week. I think history is much kinder to this proposition than it is to yours.

From my part, I will be very happy when we reach a closure about this. Whatever that is.

If after doing the replications, the experiments say "It doesn't work, it's a fluke/a mistake/a fraud", I'll be very relieved that science have been made and another dead end has been rooted out.

The same in case of having positive results. The truth, whatever that is, has to come out.

What I would be very disappointed to see, is for the experiments to be never performed or concluded, because pre-conceptions prevent us from properly validating things out.

Happily, this proposals seems to have already entered into popular consciousness, and people, those most unruly and disobedient things,  will check things out now. For good or bad for the proposal and/or its critics, they will see it by themselves.

It isn't like this is the LHC or ITER either. You don't need billions of dollars for testing this out. It is really cheap, as potential breakthrough-testing setups go.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/04/2015 06:50 PM
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2,  you loose 99% of the power.

Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.

If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.

I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;

As a waveguide, the group velocity is something like;

v_g = c x sqrt(1 - (c/2d*f)^2)

Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.

c/2d = fc,  is the Low cut-off frequency of the waveguide.

The refractive index depends on the Low cut-off frequency as a function of the diameter,

K = 1/sqrt( 1 - (fc/f)^2)

For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.

There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.

Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.

Here is how it conserves momentum;

In the PV Model, momentum transforms as,

p => p*sqrt(K)

In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity. 

However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.

The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.

That’s IMHO as an engineer of course. Any comments?

See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space
_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering

Todd D.

In what sense does this conserve momentum?

Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.

When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.

(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,

p => p*sqrt(K)

THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.


Regards,
Todd D.

What would be the equation for the acceleration or the force, given the geometrical dimensions of the truncated cone, the Q, the input power, the frequency, and any other variables? Do you have a closed-form solution that could be compared to actual experimental results and also compared with the equation of Shawyer, and also to the equation of McCulloch ?

Regards,

JR
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 07:19 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?

Nothing. Momentum from nothing.

There is actually real science here. You have to let go of your preconceptions first, and only stick to the facts.

https://www.google.com/search?q=momentum+from+nothing&ie=utf-8&oe=utf-8

And a post I put together about the history of this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1358659#msg1358659

I need you to acknowledge what you know to be fact, and embrace what you don't know. Let any emotional attachment to your worldview go, and you'll find the truth.

All of these experimentalist are telling us they're seeing an anomaly. They can't all be idiots. Nature is telling us something. Listen.
http://physicsandphysicists.blogspot.it/2012/05/what-does-it-mean-to-be-experimentalist.html

Well as long as you understand that you are getting momentum from nothing then fine. I have no problem with oddball theories as long as you follow the logic all the way through. I'm not getting how this can be called a sail but whatever. You are also in stark disagreement with Shawyer here. That isn't a bad thing as I actually agree with you. The problem is Shawyer is wrong in a very simple and obvious way. That utterly destroys any confidence that he is competent to be involved at all. There are still the other tests but they have their own problems with frame dependence and such that they need to address.

And as for my emotional attachment to my "world view" I'm sorry but that's crap. I only note that COM, COE and frame independence are very useful principles and violating them is extremely problematical. If you can do it then my hats off to you but until then my Bayesian priors are elsewhere to say the least.

This idea of "emotional attachment" often comes up in fringe subjects. From bigfoot and UFOs to cold fusion the claim is made that people are only protecting the status quo because they have so much invested in it. Emotionally, professionally, financially they are committed. This argument rarely works out. Proponents of cold fusion for example charged that there was a "hot fusion mafia" actively opposing cold fusion research. How did that work out for them? I will leave bigfoot and UFOs for you to ponder.

I could offer the counter proposition that people are emotionally drawn to these kinds of hopeful theories. Christians who are sure the second coming is just around the corner. Spiritualists who believe in ghosts and a rich rewarding afterlife. UFO buffs with "I want to believe" t-shirts. And yes space buffs who would really like to have a reactionless drive. Me? I have a lotto ticket that I'm sure has a good chance this week. I think history is much kinder to this proposition than it is to yours.

From my part, I will be very happy when we reach a closure about this. Whatever that is.

If after doing the replications, the experiments say "It doesn't work, it's a fluke/a mistake/a fraud", I'll be very relieved that science have been made and another dead end has been rooted out.

The same in case of having positive results. The truth, whatever that is, has to come out.

What I would be very disappointed to see, is for the experiments to be never performed or concluded, because pre-conceptions prevent us from properly validating things out.

Happily, this proposals seems to have already entered into popular consciousness, and people, those most unruly and disobedient things,  will check things out now. For good or bad for the proposal and/or its critics, they will see it by themselves.

It isn't like this is the LHC or ITER either. You don't need billions of dollars for testing this out. It is really cheap, as potential breakthrough-testing setups go.

But you see there will never ever ever be closure. There was not closure for cold fusion. The latest conference was just last month. There was not closure with UFOs, just watch the history channel. My lotto tick my not win but there is always next week. Whatever experiment that is done there will be objections that it was not done correctly.

And if there is an effect there is no doubt that it will be discovered. In fact the main thing that convinces me that there is no effect is that it has not been discovered already.

And yes the experiments are pretty cheap. If there were any detectable probability of success the free market would be all over this. You don't need public spending for something like this. Not that I really object much to public spending. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: squid on 05/04/2015 07:28 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

A sail in what medium?

Nothing. Momentum from nothing.

There is actually real science here. You have to let go of your preconceptions first, and only stick to the facts.

https://www.google.com/search?q=momentum+from+nothing&ie=utf-8&oe=utf-8

And a post I put together about the history of this:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1358659#msg1358659

I need you to acknowledge what you know to be fact, and embrace what you don't know. Let any emotional attachment to your worldview go, and you'll find the truth.

All of these experimentalist are telling us they're seeing an anomaly. They can't all be idiots. Nature is telling us something. Listen.
http://physicsandphysicists.blogspot.it/2012/05/what-does-it-mean-to-be-experimentalist.html

No, not momentum from nothing. Thank you for the links to these papers about Casimir momenta, as they are quite interesting from a pure physics standpoint. Fiegel's 2004 paper is unfortunately rather mathematically dense, if coherent. I will direct you to a different mathematical approach (using Green's functions, rather than QED considerations) by Birkeland and Brevik: http://arxiv.org/pdf/0707.2528v2.pdf You may find the discussion section (at the very end) very illuminating.

Unfortunately, they also show that this momentum is not generated from nothing. I quote:

Quote
. On physical grounds one may ask: where does the net electromagnetic
momentum come from? Obviously, it cannot come from ’nothing’. We are
actually comparing two different physical situations here. The first is when
the conducting plates are infinitely far separated. This is our initial ’vacuum’
state. The final state is when the plates have been brought close to each other,
infinitely slowly.

We can think of this situation analogously to many others incorporating "hidden momentum" in E&M theory, in more conventional situations. An additional momentum appears because we have not fully accounted for momentum in our initial conditions. Please see this excellent paper by Babson, Reynolds, Bjorkquist and Griffiths (I believe with some googling you might be able to find a colloquium he gave on the subject): http://gr.physics.ncsu.edu/files/babson_ajp_77_826_09.pdf

These are rather subtle theoretical points, and probably not well appreciated by most physicists, who for the most part have not thought about electromagnetic theory since fighting through Jackson problems through graduate school.

However, the end result is always the same: we cannot get something for nothing. Conservation of momentum relies on translational invariance of the theory, which is strictly preserved in all reasonable physical theories. There simply is no evidence that we need anything beyond simple E&M to understand the physics of the EM drive.

Besides, consider the prediction of the momentum imbalance [really referring to a difference in momentum between left and right propagating fields due to the chiral nature of the dielectric] derived by Birkeland and Brevik -- equation 89 in their paper. The pre-factor before chi is on the order of 10^(-21), even for plates separated by 1 micron... and chi is a small parameter [especially in vacuum, whose biefringence is negligible until you reach incredibly high magnetic fields]. I think we can rule out "Casimir momentum"-type explanations for the EM drive.

Speaking to your comment... why do you discount the possibility that what the experimentalists are telling us is that they have not accounted for all sources of error? Occam's razor would after all lead us to this explanation. The barely repeatable 'thrusts', the differences when pointing in different directions (even in vacuum) also lead us to this conclusion.

And why do you discount the many, far more precise experiments testing E&M and special relativity that this drive clearly violates? The preponderance of even experimental evidence is not in favor of the EM drive being a real effect.

I am looking forward to the July experiments as well, so we can conclusively put this to bed. I still can't understand
why the first thought wasn't to fully enclose the test article and RF supply and do a torsion pendulum type experiment. It's obvious, and if it was good enough for Cavendish it should be good enough for NASA.

One final point: criticism based on existing theory is a perfectly valid way to judge experiments. It happens all the time when scientists submit grant proposals or papers for review. And the comments in this forum have been far less vicious than what you see every day as a working scientist...


Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JPHar on 05/04/2015 07:40 PM
Let the experiments do the talking, become your own worst critic, and find the truth regardless if that inconveniences some or most people's preconceptions. Including yours.

This is the point we should be starting at.  This is why I suggested an affordable experiment design.  I'd love to see more affordable experiment designs by others.  Even if an idea seems like it may not pan out, or uses old tools, it's better to have the means to falsify an idea than to argue theory until we're blue in the face.

I like theory.  It's fun!  But experimentalists are the ultimate moderators.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WarpTech on 05/04/2015 07:47 PM
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2,  you loose 99% of the power.

Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.

If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.

I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;

As a waveguide, the group velocity is something like;

v_g = c x sqrt(1 - (c/2d*f)^2)

Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.

c/2d = fc,  is the Low cut-off frequency of the waveguide.

The refractive index depends on the Low cut-off frequency as a function of the diameter,

K = 1/sqrt( 1 - (fc/f)^2)

For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.

There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.

Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.

Here is how it conserves momentum;

In the PV Model, momentum transforms as,

p => p*sqrt(K)

In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity. 

However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.

The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.

That’s IMHO as an engineer of course. Any comments?

See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space
_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering

Todd D.

In what sense does this conserve momentum?

Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.

When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.

(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,

p => p*sqrt(K)

THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.


Regards,
Todd D.

What would be the equation for the acceleration or the force, given the geometrical dimensions of the truncated cone, the Q, the input power, the frequency, and any other variables? Do you have a closed-form solution that could be compared to actual experimental results and also compared with the equation of Shawyer, and also to the equation of McCulloch ?

Regards,

JR

Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;

p = h/lambda

wavelength depends on velocity, and v_g is a variable inside the frustum.

That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.

I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.

Todd D.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ThereIWas3 on 05/04/2015 07:47 PM
2) here are some tests by Eagleworks and the thrust per watt.

A) 1932.6 MHz 5.4 uN/W
 B) 1936.7 MHz 3.0 uN/W
C) 1880.4 MHz 21.3 uN/W
D) 2168 MHz no thrust detected, cause thought to be the lack of the dielectric resonator.

Does this indicate some resonance effect with the dimensions of the copper frustrum?  I note that the wavelength at 1936 MHz is about 15.4cm and at 1880 MHz it is 15.9cm.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Space Ghost 1962 on 05/04/2015 08:11 PM
The theory papers out there are clearly not the issue to debate here. The device producing anomalous thrust is the issue here. Anybody can come up with a bunk theory. The Emdrive is still a black box deserving expert attention.

Everybody assumes that this thing is acting like a quantum rocket (and taking all sorts of liberties with established science to justify that), based off what I see, it is a sail.

It looks more to me like a form of  "frame dragging" propulsion. Where its cryptic is that the "details" and "model" might depend on dragging in e/m field mesh, or gravitational field mesh - that's not consistent.

Also, group and phase velocities seem to be not kept straight. That might be where the "unacceptable"  to many aspects might come in. Alternatively, a juxtaposition of "near field" and "far field" terms could be present here, and a form of chaotic leveraging explains some of these experimental results. In that case, the reconciliation of where the forces come from is tedious examination of apparatus to follow a chain.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 08:37 PM
So this made me think about the time I took a 3 port circulator apart. For those that are not familiar with circulators, the work like this:
Put power in port 1 and it comes out port 2, put it in 2 and it comes out 3, put it in 3 and it comes out 1. All with out much loss. But if you try to go backwards, say 3 to 2,  you loose 99% of the power.

Cool little device. So when I take it apart all it is is a flat triangle of copper, 2 triangle shaped pieces of ferrite, and a magnet.

If you don't know the math behind it, is looks at first blush as "silly" as the emdrive. No way could it do that. But it does. This thing may well work, we just don't know the math.

I'm an Engineer and I've studied the Polarizable Vacuum Model of General Relativity. What it would say is the following;

As a waveguide, the group velocity is something like;

v_g = c x sqrt(1 - (c/2d*f)^2)

Where, c is the usual speed of light, d is the diameter of the cylinder, and f is the frequency of the microwave excitation.

c/2d = fc,  is the Low cut-off frequency of the waveguide.

The refractive index depends on the Low cut-off frequency as a function of the diameter,

K = 1/sqrt( 1 - (fc/f)^2)

For f >> fc, K~1. But for frequencies in the band fc1 < f <~ fc2, K is much larger.

There is a strong gradient in the refractive index from one end of the cone to the other. This "mimics" gravity, as interpreted in the PV Model.

Therefore, we can assume there is a "gravitational" gradient in the microwave band refractive index, along the length of the cone. At one end they have diameter d1, and at the other end they have diameter d2, and d1 > d2. Below fc1, the mode frequencies exponentially decay to zero. Just like the Casimir effect.

Here is how it conserves momentum;

In the PV Model, momentum transforms as,

p => p*sqrt(K)

In a resonant cavity, p is the SUM of all the photons “in phase", minus the losses of the cavity. 

However, as photons “fall” from the large end toward the small end, they gain momentum, which is passed on to the cone when they are reflected from the small end. The photon then loses momentum as it travels back to the large end, where it imparts “less” momentum to the large end. The result is a NET propulsion in the direction of the small end. In other words, the photons are blue-shifted falling forward, and red-shifted going backwards, due to the gradient in the refractive index. It is literally gravitational red & blue shift, according to the PV Model.

The interesting thing is, the refractive index in the waveguide does not depend on the power of the microwaves, or the energy density. It is simply a matter of the geometry and frequency band relative to the cut-off. What matters more, is having enough resonant momentum stored to make the effect noticeable.

That’s IMHO as an engineer of course. Any comments?

See PV Model: https://www.researchgate.net/publication/223130116_Advanced_Space
_Propulsion_Based_on_Vacuum_%28Spacetime_Metric%29_Engineering

Todd D.

In what sense does this conserve momentum?

Treat the device as a black box. I don't know or care what is happening inside it. At time T0 it has no momentum. Turn it on and let it accelerate so that it has some velocity and so momentum at time T1. Unless you can point to something with the same amount of momentum going in the other direction then by definition you have violated conservation of momentum. What happens inside the box simple does not affect that fact.

When you drop an object and it falls to the ground. Relative to you, it gained momentum from the gravitational field. It did not expel any propellant to fall. The gravitational field is simply a gradient in the refractive index of the vacuum surrounding the Earth. If you can explain conservation of momentum for falling objects in a gravitational field, then you have your answer.

(Edit) In other words, if the cavity were not tapered, then you have equal momentum inside traveling left and right. At T0, it will go nowhere. However, because it is tapered such that you have a gradient in the refractive index, then "just like gravity", photons will be blue shifted moving into higher K, and red shifted moving into lower K, because momentum,

p => p*sqrt(K)

THIS is a violation of conservation of momentum. Therefore, the cavity must move to conserve momentum, as it tries to establish equilibrium with it's own internal stress.


Regards,
Todd D.

What would be the equation for the acceleration or the force, given the geometrical dimensions of the truncated cone, the Q, the input power, the frequency, and any other variables? Do you have a closed-form solution that could be compared to actual experimental results and also compared with the equation of Shawyer, and also to the equation of McCulloch ?

Regards,

JR

Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;

p = h/lambda

wavelength depends on velocity, and v_g is a variable inside the frustum.

That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.

I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.

Todd D.

Well I certainly agree that You will never get Newtonian-type COM equation out of this. That's what makes it a violation of COM. Hard and simple. You are free to develop a theory that does not conserve momentum but you should call it what it is.

And I don't care what frames are inside the thing. Frames of reference are mathematical fictions. They don't exist. I should not need two frames of reference but only one and it is chosen only for convenience not truth. Any frame should do. Again you are free to develop a theory with a preferred frame that is real but you need to know that that is what you are doing and tell people that that is what you are doing.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: rfmwguy on 05/04/2015 08:57 PM
Big spike at 1.89 GHz. Is this ideal cavity resonance? Believe I read a circulator is used to deal with isolating standing waves from the signal source. Any standing wave/return loss measurements been made on the frustrum?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/04/2015 09:08 PM

What would be the equation for the acceleration or the force, given the geometrical dimensions of the truncated cone, the Q, the input power, the frequency, and any other variables? Do you have a closed-form solution that could be compared to actual experimental results and also compared with the equation of Shawyer, and also to the equation of McCulloch ?

Regards,

JR

Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;

p = h/lambda

wavelength depends on velocity, and v_g is a variable inside the frustum.

That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.

I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.

Todd D.


What is the acceleration vs. time profile that you envision out of your model under a constant power input? 
Would it be like a short-time impulse or a Dirac delta function when the system is energized? or
would it be a constant acceleration forever and ever under a constant power input ? (in which case it is extremely difficult to understand how momentum would be conserved with a completely enclosed metallic cavity and it would also appear to involve an energy paradox)

Regards

JR
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WarpTech on 05/04/2015 10:39 PM
<snip>

Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;

p = h/lambda

wavelength depends on velocity, and v_g is a variable inside the frustum.

That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.

I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.

Todd D.

Well I certainly agree that You will never get Newtonian-type COM equation out of this. That's what makes it a violation of COM. Hard and simple. You are free to develop a theory that does not conserve momentum but you should call it what it is.

And I don't care what frames are inside the thing. Frames of reference are mathematical fictions. They don't exist. I should not need two frames of reference but only one and it is chosen only for convenience not truth. Any frame should do. Again you are free to develop a theory with a preferred frame that is real but you need to know that that is what you are doing and tell people that that is what you are doing.

If you insist on using Newtonian mechanics, then you will never understand COM in terms of General Relativity. I have not formulated a "new" theory, I'm using GR correctly. If you learn how to do COM in GR, then you would have no trouble seeing that this does indeed conserve momentum. The fact that you "don't care what is inside" is what is preventing you from learning. The "gravitational" field effect of a variable speed of light, acting on the photons inside the Frustum is what makes it move. If you neglect that it has a gravitational field inside it, then you neglect the very essence of how it works and why momentum is conserved. If you want to neglect GR and "believe" COM is violated, then that is your prerogative.

As for why it was not discovered already, I'm kicking myself in the a** for not thinking of this setup 10 years ago when I realized we can mimic gravity over a limited bandwidth with much less energy than over the full bandwidth of all light and matter waves. When my colleague and I wrote our EGM III paper, we had a resonant cavity like this in mind, but we didn't consider the taper.

Best Regards,
Todd D.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/04/2015 11:28 PM
Big spike at 1.89 GHz. Is this ideal cavity resonance? Believe I read a circulator is used to deal with isolating standing waves from the signal source. Any standing wave/return loss measurements been made on the frustrum?
There is a dual directional coupler to take the measurements, it feeds a 2' cable to the frustum. I don't think he could hang the ddc directly to the frustum without compromising the thrust measurement.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/04/2015 11:31 PM
<snip>

Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;

p = h/lambda

wavelength depends on velocity, and v_g is a variable inside the frustum.

That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.

I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.

Todd D.

Well I certainly agree that You will never get Newtonian-type COM equation out of this. That's what makes it a violation of COM. Hard and simple. You are free to develop a theory that does not conserve momentum but you should call it what it is.

And I don't care what frames are inside the thing. Frames of reference are mathematical fictions. They don't exist. I should not need two frames of reference but only one and it is chosen only for convenience not truth. Any frame should do. Again you are free to develop a theory with a preferred frame that is real but you need to know that that is what you are doing and tell people that that is what you are doing.

If you insist on using Newtonian mechanics, then you will never understand COM in terms of General Relativity. I have not formulated a "new" theory, I'm using GR correctly. If you learn how to do COM in GR, then you would have no trouble seeing that this does indeed conserve momentum. The fact that you "don't care what is inside" is what is preventing you from learning. The "gravitational" field effect of a variable speed of light, acting on the photons inside the Frustum is what makes it move. If you neglect that it has a gravitational field inside it, then you neglect the very essence of how it works and why momentum is conserved. If you want to neglect GR and "believe" COM is violated, then that is your prerogative.

As for why it was not discovered already, I'm kicking myself in the a** for not thinking of this setup 10 years ago when I realized we can mimic gravity over a limited bandwidth with much less energy than over the full bandwidth of all light and matter waves. When my colleague and I wrote our EGM III paper, we had a resonant cavity like this in mind, but we didn't consider the taper.

Best Regards,
Todd D.

I don't believe GR is even relevant but even if it were it makes no difference.

Take your engine. No power attached, no resonance it is just cold and dead. Calculate the momentum of the entire system. By whatever definition of momentum you are using.

Turn on the power. Now you can have imbalanced momentum, resonance whatever you want. I don't care. Let it accelerate up to some velocity.

Turn it back off. Let it cool to a cold dead object again. Melt it down to a simple copper sphere if you want. Now calculate the momentum of the system. Again by whatever definition of momentum you are using.

If the second calculation does not equal the first then you have violated COM. GR never enters into it because any definition of momentum must reduce to Newtonian momentum on the limit of ordinary objects moving at small speeds in flat space. That value is not conserved and therefore your GR did not conserve momentum. The whole point of momentum is as a conserved value that prevents this kind of thing. Take that away and the whole concept of momentum isn't very useful.

There is no reasonable definition of momentum that can call this a conservation of momentum. There is no reason to even want to. Bite the bullet and call it what it is.

If you want a mechanism for GR to violate COM that's fine with me. But you do have to call it what it is. And you will have problems showing a detectable GR effect on these energy scales.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/04/2015 11:40 PM
New article over on NextBigFuture which might be worth people's time to have a read through.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KittyMoo on 05/04/2015 11:58 PM
<snip>

Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;

p = h/lambda

wavelength depends on velocity, and v_g is a variable inside the frustum.

That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.

I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.

Todd D.

Well I certainly agree that You will never get Newtonian-type COM equation out of this. That's what makes it a violation of COM. Hard and simple. You are free to develop a theory that does not conserve momentum but you should call it what it is.

And I don't care what frames are inside the thing. Frames of reference are mathematical fictions. They don't exist. I should not need two frames of reference but only one and it is chosen only for convenience not truth. Any frame should do. Again you are free to develop a theory with a preferred frame that is real but you need to know that that is what you are doing and tell people that that is what you are doing.

If you insist on using Newtonian mechanics, then you will never understand COM in terms of General Relativity. I have not formulated a "new" theory, I'm using GR correctly. If you learn how to do COM in GR, then you would have no trouble seeing that this does indeed conserve momentum. The fact that you "don't care what is inside" is what is preventing you from learning. The "gravitational" field effect of a variable speed of light, acting on the photons inside the Frustum is what makes it move. If you neglect that it has a gravitational field inside it, then you neglect the very essence of how it works and why momentum is conserved. If you want to neglect GR and "believe" COM is violated, then that is your prerogative.

As for why it was not discovered already, I'm kicking myself in the a** for not thinking of this setup 10 years ago when I realized we can mimic gravity over a limited bandwidth with much less energy than over the full bandwidth of all light and matter waves. When my colleague and I wrote our EGM III paper, we had a resonant cavity like this in mind, but we didn't consider the taper.

Best Regards,
Todd D.

I don't believe GR is even relevant but even if it were it makes no difference.

Take your engine. No power attached, no resonance it is just cold and dead. Calculate the momentum of the entire system. By whatever definition of momentum you are using.

Turn on the power. Now you can have imbalanced momentum, resonance whatever you want. I don't care. Let it accelerate up to some velocity.

Turn it back off. Let it cool to a cold dead object again. Melt it down to a simple copper sphere if you want. Now calculate the momentum of the system. Again by whatever definition of momentum you are using.

If the second calculation does not equal the first then you have violated COM. GR never enters into it because any definition of momentum must reduce to Newtonian momentum on the limit of ordinary objects moving at small speeds in flat space. That value is not conserved and therefore your GR did not conserve momentum. The whole point of momentum is as a conserved value that prevents this kind of thing. Take that away and the whole concept of momentum isn't very useful.

There is no reasonable definition of momentum that can call this a conservation of momentum. There is no reason to even want to. Bite the bullet and call it what it is.

If you want a mechanism for GR to violate COM that's fine with me. But you do have to call it what it is. And you will have problems showing a detectable GR effect on these energy scales.

You puff and blow, but EW is trying to eliminate external forces and so investigate *anomalous forces*
I support them in a difficult task... Do you?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/05/2015 12:07 AM
<snip>

Not yet... I'm just now coming to grips with this myself. My light-bulb went off when I realized if the frequency of the microwaves is very close to the cut-off frequencies, then the speed of light will have a very large gradient inside the Frustum. Relative to the "traveling" waves (photons) attempting to move at the speed of light from end to end. When they approach the small end, their wavelength is squeezed by the reduced group velocity. Momentum depends on wavelength;

p = h/lambda

wavelength depends on velocity, and v_g is a variable inside the frustum.

That is where the momentum is coming from. Inside the Frustum, relative to the traveling waves you have an accelerated reference frame, into which you are injecting photons that are affected by this manufactured "gravitational" field, that must be compensated for by moving the Frustum.

I'll see what I can come up with for a formal equation, but I've got a day job. As for @ppnl, you will never get a Newtonian-type COM equation out of this. The two frames are the Frustum, and the frame of the moving photons inside it. The acceleration is caused by the geometry of the waveguide or a variable refractive index, i.e. the GR or PV Interpretation lead to the same result.

Todd D.

Well I certainly agree that You will never get Newtonian-type COM equation out of this. That's what makes it a violation of COM. Hard and simple. You are free to develop a theory that does not conserve momentum but you should call it what it is.

And I don't care what frames are inside the thing. Frames of reference are mathematical fictions. They don't exist. I should not need two frames of reference but only one and it is chosen only for convenience not truth. Any frame should do. Again you are free to develop a theory with a preferred frame that is real but you need to know that that is what you are doing and tell people that that is what you are doing.

If you insist on using Newtonian mechanics, then you will never understand COM in terms of General Relativity. I have not formulated a "new" theory, I'm using GR correctly. If you learn how to do COM in GR, then you would have no trouble seeing that this does indeed conserve momentum. The fact that you "don't care what is inside" is what is preventing you from learning. The "gravitational" field effect of a variable speed of light, acting on the photons inside the Frustum is what makes it move. If you neglect that it has a gravitational field inside it, then you neglect the very essence of how it works and why momentum is conserved. If you want to neglect GR and "believe" COM is violated, then that is your prerogative.

As for why it was not discovered already, I'm kicking myself in the a** for not thinking of this setup 10 years ago when I realized we can mimic gravity over a limited bandwidth with much less energy than over the full bandwidth of all light and matter waves. When my colleague and I wrote our EGM III paper, we had a resonant cavity like this in mind, but we didn't consider the taper.

Best Regards,
Todd D.

I don't believe GR is even relevant but even if it were it makes no difference.

Take your engine. No power attached, no resonance it is just cold and dead. Calculate the momentum of the entire system. By whatever definition of momentum you are using.

Turn on the power. Now you can have imbalanced momentum, resonance whatever you want. I don't care. Let it accelerate up to some velocity.

Turn it back off. Let it cool to a cold dead object again. Melt it down to a simple copper sphere if you want. Now calculate the momentum of the system. Again by whatever definition of momentum you are using.

If the second calculation does not equal the first then you have violated COM. GR never enters into it because any definition of momentum must reduce to Newtonian momentum on the limit of ordinary objects moving at small speeds in flat space. That value is not conserved and therefore your GR did not conserve momentum. The whole point of momentum is as a conserved value that prevents this kind of thing. Take that away and the whole concept of momentum isn't very useful.

There is no reasonable definition of momentum that can call this a conservation of momentum. There is no reason to even want to. Bite the bullet and call it what it is.

If you want a mechanism for GR to violate COM that's fine with me. But you do have to call it what it is. And you will have problems showing a detectable GR effect on these energy scales.

You puff and blow, but EW is trying to eliminate external forces and so investigate *anomalous forces*
I support them in a difficult task... Do you?

My support isn't going to help him and my opposition isn't going to harm him. I strongly encourage everyone to do what they think is useful. I am doing the same.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: rfmwguy on 05/05/2015 12:10 AM
I'm starting to believe COM, linear and angular, is no longer the brick wall I once thought, especially in the quantum realm:

http://arxiv.org/abs/0803.2811

...from Cornell, and other sources regarding "Transmutation of Momentum"

Way over my humble head: "Transmutation methods are developed for equations of the form x2 φ“ + x2(k2” - q̃(x)) φ = (v2 - (1/4)) φ, with v as spectral variable, which correspond to problems in quantum scattering theory at fixed energy k2 (here v ˜ l + (1/2) with l complex angular momentum). Spectral formulas for transmutation kernels are constructed and the machinery of transmutation theory developed by the author for spectral variable k is shown to have a version here. General Kontrorovič-Lebedev theorems are also proved."

Transmutation via the momentum plane

R. Carroll andD. S. Jones Communicater
Article first published online: 6 JUN 2011
DOI: 10.1002/mma.1670060129
Copyright © 1984 John Wiley & Sons, Ltd

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: PushHigher on 05/05/2015 01:13 AM
Gravity certainly conserves momentum.

When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

PPNL

I think you answered your own question here.  Assuming the EM drive can create a gravity gradient, the created gravity well extends to infinity via inverse square law.  It is essentially tugging at whatever is in front of it.  The reason it tugs harder toward the front rather than the back is due to the front having a larger more shallow gravity well than the one in the back - the larger one wins by virtue of being closer. 

(http://i.imgur.com/l6pKM5C.png)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/05/2015 02:21 AM
Gravity certainly conserves momentum.

When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

PPNL

I think you answered your own question here.  Assuming the EM drive can create a gravity gradient, the created gravity well extends to infinity via inverse square law.  It is essentially tugging at whatever is in front of it.  The reason it tugs harder toward the front rather than the back is due to the front having a larger more shallow gravity well than the one in the back - the larger one wins. 

(http://i.imgur.com/l6pKM5C.png)

Well understand that I seriously doubt that any gravitational field is being generated here. You want to theorize that it is? I think the theoretical problems with artificial gravity are massive. But fine we can leave it to the experimentalists for now.

If it is tugging at whatever is in front then that thing will move and that will balance momentum. We don't have to talk about unbalanced momentum in the device or worry about GR at all. That whole discussion becomes pointless.

Now if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.

Now I could propose that the amount of power needed to generate a gravitational field depends on the motion of what that field is pulling on. That seems reasonable even in the absence of any mechanism. But the absence of a credible mechanism creates serious doubt.

I said long ago that if you had a mechanism to react against the local gravitational gradient then you could solve both COM violations and COE violations. But there is no reason to suspect there is any mechanism to do that. And it is in stark disagreement with what Shawyer claims is happening - this drive would be far more useful. It really would be kinda like sailing.

You want to claim that the EMdrive is doing this? Fine, but lets end this nonsense of claiming that this or that theory does not violate COM when it obviously does.

And given a choice of owning the patten on the drive and owning next weeks lotto ticket I will choose the lotto ticket. Much much better odds.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: PushHigher on 05/05/2015 03:01 AM
Now if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.

Thanks for your response

No, from what I'm reading - constant input energy does lead to a sub-C speed barrier.  What I visualize is happening is that as drive accelerates the shape of the frustum becomes more cylindrical until it is and there is no gravity gradient and therefore no more acceleration.

I cannot attest to Shawyers statements nor prove that a gravity gradient is being created.  I agree this is all conjecture at this point.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/05/2015 03:22 AM
Now if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.

Thanks for your response

No, from what I'm reading - constant input energy does lead to a sub-C speed barrier.  What I visualize is happening is that as drive accelerates the shape of the frustum becomes more cylindrical until it is and there is no gravity gradient and therefore no more acceleration.

I cannot attest to Shawyers statements nor prove that a gravity gradient is being created.  I agree this is all conjecture at this point.

No I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: whoster69 on 05/05/2015 03:42 AM
I just found you guys.  I can't say this enough, THANK YOU!  I am so excited I don't think I can sleep tonight!  I can't wait to hear more!
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sanman on 05/05/2015 04:27 AM
If EMdrive becomes a sufficiently huge issue in the public eye, then couldn't Mythbusters be called in to spend some money on proving or disproving it? Or are they not professional enough?

(http://www.jedihawk.com/wp-content/uploads/2013-09-15_mb_reject_your_reality_600x450.jpg)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tchernik on 05/05/2015 04:36 AM
If EMdrive becomes a sufficiently huge issue in the public eye, then couldn't Mythbusters be called in to spend some money on proving or disproving it? Or are they not professional enough?


I doubt they will be interested in anything that doesn't explode, breaks or ends up flying away.

And the initial Emdrive tests would hardly have enough force to push a sheet of paper.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: PushHigher on 05/05/2015 04:55 AM
No I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.

I haven't read anything regarding frame reference problems, I'll look into that - thanks for the tip.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/05/2015 06:16 AM
I'm starting to believe COM, linear and angular, is no longer the brick wall I once thought, especially in the quantum realm:

http://arxiv.org/abs/0803.2811

...from Cornell, and other sources regarding "Transmutation of Momentum"

Way over my humble head: "Transmutation methods are developed for equations of the form x2 φ“ + x2(k2” - q̃(x)) φ = (v2 - (1/4)) φ, with v as spectral variable, which correspond to problems in quantum scattering theory at fixed energy k2 (here v ˜ l + (1/2) with l complex angular momentum). Spectral formulas for transmutation kernels are constructed and the machinery of transmutation theory developed by the author for spectral variable k is shown to have a version here. General Kontrorovič-Lebedev theorems are also proved."

Transmutation via the momentum plane

R. Carroll andD. S. Jones Communicater
Article first published online: 6 JUN 2011
DOI: 10.1002/mma.1670060129
Copyright © 1984 John Wiley & Sons, Ltd

Quantum mechanics can violate conservation of momentum locally but not globally. To see how this works consider the experiments that demonstrated the violation of Bell's inequality. The local measurement of a particle on one end is ruled by probability and can be anything. But when you connect that measurement to the measurement of its entangled twin they must match. That matching is driven exactly by the need to conserve angular momentum. It will do so even if it has to apparently cheat by violating Bell's inequality.

In the matrix mechanics formulation of quantum mechanics that conservation of momentum is built in at the ground level. In fact all the classical conservation laws are built in. In fact all of Newtonian and classical physics is built in on the classical limit. In the wave mechanics formulation it was less clear that conservation of momentum was preserved. It turned out that the two formulations were equivalent.

So if you want quantum mechanics to violate momentum conservation you are out of luck. It is like squaring the circle or trisecting the angle. The math just will not allow it. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: alexterrell on 05/05/2015 06:51 AM
But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.



You get back to the perfect EM-Drive machine:

Electrical Energy in = Delta Kinetic Energy + Delta Gravitational Energy.

Which means that a chemically powered "Perfect" EM Drive cannot reach orbit* (Required: about 30MJ/kg)  . It can however levitate to 100km altitude (Required: about 1MJ/kg - and atmospheric oxygen can be used for the first 50km), where upon solar panels can accelerate it to where ever.

*Unless it dumps its fuel-product overboard like a normal rocket. So a fuel cell, then dump the water product away. In this case, a rocket-equation can apply, and I'm not sure if the device is that much better than a fully reusable single stage to orbit rocket.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: CW on 05/05/2015 11:26 AM
But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.



You get back to the perfect EM-Drive machine:

Electrical Energy in = Delta Kinetic Energy + Delta Gravitational Energy.

Which means that a chemically powered "Perfect" EM Drive cannot reach orbit* (Required: about 30MJ/kg)  . It can however levitate to 100km altitude (Required: about 1MJ/kg - and atmospheric oxygen can be used for the first 50km), where upon solar panels can accelerate it to where ever.

*Unless it dumps its fuel-product overboard like a normal rocket. So a fuel cell, then dump the water product away. In this case, a rocket-equation can apply, and I'm not sure if the device is that much better than a fully reusable single stage to orbit rocket.

And here I thought that the whole purpose of an EM-drive was to do away with anything chemical needed for propulsion..
;)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sghill on 05/05/2015 01:37 PM
From the article: "Mr. Joosten and Dr. White stated that “a one-way, non-decelerating trip to Alpha Centauri under a constant one milli-g acceleration” from an EM drive would result in an arrival speed of 9.4 percent the speed of light and result in a total transit time from Earth to Alpha Centauri of just 92 years."

I just want to point out that if Pioneer 10 had been an EM Drive equipped probe (with appropriate power source) when it was launched in March 1972, it would be just shy of being half-way to Alpha Centauri right now! (about 47%)

There are plenty of readers on this forum who remember when it was launched.

For those who don't know, Pioneer 10 was the first man-made object to achieve solar escape velocity.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/05/2015 04:05 PM
So rather than delve into any known physics, I decided to look at this with a "clean sheet" approach and see if I could find rhyme or reason in any of this:


2) here are some tests by Eagleworks and the thrust per watt.

A) 1932.6 MHz 5.4 uN/W
 B) 1936.7 MHz 3.0 uN/W
C) 1880.4 MHz 21.3 uN/W
D) 2168 MHz no thrust detected, cause thought to be the lack of the dielectric resonator.

And the China tests at 2.45 (2.457 seemed to be peak) with a dirty source and they got a lot of thrust as well.



1. D and the China test had no dielectric resonator, so it doesn't seem to be an absolute requirement.
2.  The China test used a dirty fat wide harmonically filled signal. Paul M. Also observed that with FM and AM on his signal provided more thrust. That made me wonder if there was a pattern to the harmonics effecting the operation of the drive. It seems there is....

The only test that provided no thrust is the only test that did not have an odd harmonic close to 160.2 GHz, the others did. Between A and B, more thrust per watt was provided by the unit at a lower Q but the harmonic was closer.

I find it somewhat perplexing, but there seems to be some relationship between the drives operation and the peak of the CMBR. But I have a very limited data set to work with. :'( It may be a tenuous connection at best, but it might provide some insight to what is going on.

If there is some connection, tests at 1884.7, 1907.1, and 1930.1 MHz would be useful, as well as 2464 MHz with a dirty magnetron.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RonM on 05/05/2015 04:14 PM
If EMdrive becomes a sufficiently huge issue in the public eye, then couldn't Mythbusters be called in to spend some money on proving or disproving it? Or are they not professional enough?

I doubt they would do it, but if they did the Mythbusters would go large.

Instead of some puny magnetron out of a microwave oven, the Mythbusters would use one out of a surplus radar system. The bigger the better. Then they would crank it up until molten copper started spewing out of the thing and there's your thrust!  :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/05/2015 05:27 PM
There's an article on the Extreme Tech website now about this which is probably the best I've seen on a general tech/science website, not that this is saying much considering the low standard of most of the articles.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Hanelyp on 05/05/2015 05:43 PM
The Mythbusters, despite being the best regular demonstration of scientific method in popular media, don't generally operate to the necessary precision to properly review EMdrive.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 05/05/2015 06:24 PM
No I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.

I haven't read anything regarding frame reference problems, I'll look into that - thanks for the tip.

That's actually a very good point.  If space is being expanded behind and contracted in front of a craft, the "faster" one would go, likely would require exponentially more power as more space is compressed behind the craft and space is being expanded much further out to achieve the effective velocities.  It would almost seem that something like the "Cube Square Law" when it comes to the volume of space affected, should apply here.

     On the other hand, if it is a constant volume of space being expanded and compressed, but at a higher cyclic rate, then the power requirements would still increase, but likely at a pretty much linear rate.  Or so it would seem.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: masonke on 05/05/2015 06:55 PM
Chris I read that the confirmation of the EM Drive also helps to validate to possibility of a WARP DRIVE from Dr. White.

Is this TRUE?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/05/2015 07:14 PM
No. Vastly different orders of magnitude.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/05/2015 07:20 PM
No. Vastly different orders of magnitude.
Honestly, I think you're underestimating what EM Drive would represent if true. EM Drive if real is an enormous departure from the current accepted laws of physics. Anyone who says otherwise is lying to you.

If EM drive is real (which it isn't), then something like a warp effect could certainly be part of the new physics behind it.

Which is all the more reason to take EM drive with an enormous grain of salt. There's a powerful temptation to let wishes be horses.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Robotbeat on 05/05/2015 07:35 PM
I'm saying it's as certainly not real as just about anything I can imagine. Nothing can be 100%.

But while I'm certain the effect is an artifact, if it WERE to be true, the implications would be absurd. Unlimited energy (and yes, I know people try to tack on energy conservation whenever someone points it out, but it seems super contrived and kind of gutless), human interstellar travel in our lifetimes, even the possibility of engineering a reverse in the heat death of the Universe.

The laws of physics do not yield easily. I am confident this is a fluke as much as I'm confident of anything in physics. But I just want people to be aware of what the real implications of this would likely be, partly because it informs the likelihood of whether or not it should be taken seriously and how high the standard of proof really needs to be.


Remember, because it'd be so incredible, there's an enormous temptation to trick yourself into thinking it's real even when it's not.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Space Ghost 1962 on 05/05/2015 08:22 PM
No. Vastly different orders of magnitude.
Honestly, I think you're underestimating what EM Drive would represent if true. EM Drive if real is an enormous departure from the current accepted laws of physics. Anyone who says otherwise is lying to you.

If EM drive is real (which it isn't), then something like a warp effect could certainly be part of the new physics behind it.

Which is all the more reason to take EM drive with an enormous grain of salt. There's a powerful temptation to let wishes be horses.

Your god like omnipotence is impressive here and obviously there's no need to continue testing it. This sort of attitude has bedevilled this thread and I expected better of a regular poster on this forum. Especially when you're making claims about it that have been explained on multiple occasions are not applicable to it, even with my limited understanding I can understand it is not a free unlimited energy device. It only puts out kinetic energy wise what's put into it electromagnetically, it isn't a magical device from Harry Potter.

He's politely expressing skepticism without being rude or defamatory. Why be hostile back?

There's considerable to prove if real. If one is an advocate, one wants skepticism and to eventually marshal enough proof.

Whole lot better than outright conclusory declarations.

Maybe I'm just fed up with seeing this attitude replicated a hundred times in the media coverage of this story. Did those at NASA who kindly posted here deserve the harsh treatment that they were subjected to by some on this thread?

Nope. Understand the sensitivity. You have no idea how well I understand it.

I'm afraid that's the times we live in. My preference is for a neutral environment. But others seem to have different tastes.

Unlike Robobeat, more willing to give the benefit of the doubt to allow time to sort things out. However this has dangers too, so it's not all for free.

Among others, I spent time going through Pons and Flieschmann, as well as the cavitation bubble stuff too at UCLA. As well as some pharmaceutical things too - 2 out of 10 actually worked out to be real. Amazing what a physics and mathematics background brings.

Oh, and the Lorenz effects with SSC magnets that bent abruptly. And the broken wire in the superluminal radiation stuff. Been polite and thoughtful through it all. You see, I'd like *any* part of it to even *slightly* be true.

Luis Alvarez was an inspiration. Miss him and Owen Chamberlain - was at their memorials, as well as the shindig for  Charles Hard Townes at SSL (he had me record a personal message for Apollo Saturn team members at his 99th - any out there let me know and I'll play it for you in person).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RonM on 05/05/2015 08:32 PM
But while I'm certain the effect is an artifact, if it WERE to be true, the implications would be absurd. Unlimited energy (and yes, I know people try to tack on energy conservation whenever someone points it out,....

@Robotbeat.  Serious question for you.  You've mentioned several times that a working EMDrive would be an unlimited energy device.  I don't follow your logic though.  The EM drive converts electromagnetic input energy into output kinetic energy at some efficiency yet to be discovered, minus friction and other parasitic factors.  How does that make a free energy device?  Are you suggesting that it converts at greater than 100%?  How so?

I think what Robotbeat is referring to has to do with differences in kinetic energy. To double the velocity of an object takes four times the energy. However, many EM drive theories state that to double the velocity of an object only takes double the energy. So, you use the EM drive to increase the velocity, then use a normal system to convert the KE into heat for your heat engine, and you get extra energy from nowhere, free energy.

If your theory gets you free energy it is wrong.

Maybe something interesting and useful is going on in these devices, but it isn't going to throw away the past hundred years of physics.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 05/05/2015 09:24 PM
Right then!

So, these two EM Drive threads are wall to wall clever people, but clearly that does not automatically mean such people know how to present themselves on the interweb. I've stepped in and cleaned up this thread for the following reasons.

1) The forum rules: http://forum.nasaspaceflight.com/index.php?topic=36479.0 - apply for all the threads on this forum (I know, crazy! Who'd have thought that!)

2) When you post on here, especially when you are responding to another poster, the forum software doesn't transport you both to a dark private room for you to go at each other. You're responding to both that person and the THOUSANDS of people reading the thread. Don't let yourself down by posting in the style of someone who's waving one's backside in the air whilst sobbing about people kicking it. ;)

3) This thread is for the discussion of the article on this thread. There's been 101 articles generated on other sites as a result, so why the main crap one has to be linked on this thread and discussed is not only a disservice to the effort that went into this site's article, it's also falling for the mass media trick of click bait. Don't fall for that, or at least respond on THAT site's comment section.

4) There were a few posts that appear to have been typed using one's nose bashing into one's keyboard, resulting in a very messy post. Remember, lots of people reading, they don't need to have to put posts through a translator to work out what is being said.

5) I'm sure this will get the traditional "OMG. Moderation like China or somefink! They appreciate my LOLZ jokes on Reddit and Facebook!". That's great, but I started this site and this forum out of the ashes of the mess that was SDC and I promised the 12 members who joined here that we'd never allow that to happen here. 30,000 members - or whatever - members later, I'm sticking to that plan.

Carry on................ :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: PushHigher on 05/05/2015 09:49 PM
I think what Robotbeat is referring to has to do with differences in kinetic energy. To double the velocity of an object takes four times the energy. However, many EM drive theories state that to double the velocity of an object only takes double the energy. So, you use the EM drive to increase the velocity, then use a normal system to convert the KE into heat for your heat engine, and you get extra energy from nowhere, free energy.

Thanks RonM,

ppnl's concerns are starting to make more sense to me.  The only way I can explain this away is the EM Drive's gravity gradient.  If you envision spacetime as a bed and a bowling ball as a spaceship, to get the bowling ball to roll forward - you have to push it laterally and also overcome the friction of the bed because it's making a large indentation into the bed.  Except in space there is no friction that hampers speed, there is friction that hampers acceleration (it becomes harder to accelerate as you approach the speed of light).   

Now imagining the bowling ball as the EM Drive.  The drive pushes down on the bed deeply and more acutely towards the back and gently and more broadly towards the front.  Push the bowling ball a bit from behind and it starts falling forward.  So in essence we are taking an enormous piece of the puzzle out of the equation. 

Thinking three dimensionally - if the EM Drive can create a more pronounced gravity well in the back and a less pronounced and broad gravity well in the front.  Same energy on both sides but the front wins because the back gravity well is mostly inside the frustum chamber pulling at the walls while the less pronounced and broad gravity well expands (more prominently) outside the frustum chamber.

Please take this with a grain of salt because I'm not a scientist and this is all based on my wild thoughts.

---
Edit - I personally don't feel that antigravity exists.  You can't pull the bed up and make the bowling ball roll. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: frobnicat on 05/05/2015 11:22 PM
But while I'm certain the effect is an artifact, if it WERE to be true, the implications would be absurd. Unlimited energy (and yes, I know people try to tack on energy conservation whenever someone points it out,....

@Robotbeat.  Serious question for you.  You've mentioned several times that a working EMDrive would be an unlimited energy device.  I don't follow your logic though.  The EM drive converts electromagnetic input energy into output kinetic energy at some efficiency yet to be discovered, minus friction and other parasitic factors.  How does that make a free energy device?  Are you suggesting that it converts at greater than 100%?  How so?

I think what Robotbeat is referring to has to do with differences in kinetic energy. To double the velocity of an object takes four times the energy. However, many EM drive theories state that to double the velocity of an object only takes double the energy. So, you use the EM drive to increase the velocity, then use a normal system to convert the KE into heat for your heat engine, and you get extra energy from nowhere, free energy.

If your theory gets you free energy it is wrong.

Maybe something interesting and useful is going on in these devices, but it isn't going to throw away the past hundred years of physics.

Here is a concrete contraption to get unlimited energy, and unlimited deltaV, given the hypothesis of constant "propellantless thrust" at constant power :
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=619550;image)
bigger (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=619549;image)

Em drives mounted on a rotor turning at 2000m/s tangential velocity (not easy but this is the kind of tangential velocity attained in some energy storage flywheels...). Em drives consuming 1kW microwave, radiating some (all ?) of this power as heat and thrusting at 1N : 1N/kW is in the ballpark of what has been experimentally claimed already. This gives 2000m/s * 1N = 2kW mechanical power to the shaft of the rotor. 2kW mechanical power at the shaft are converted to 1800W DC current by a generator (and 200W radiated as heat). Of this 1800W DC electrical power, 250W are diverted for any use we like. To keep it in line with the topic I put it to good use to power another Em drive but really we are free to use those 250W for whatever (creating mass for instance). The power splitter is not 100% efficient, it radiates 50W of power. 1800-250-50 = 1500W to feed the RF amplifier. The RF amplifier wastes (radiates) 500W as heat and pumps 1000W of clean microwave back into the Em drives on the rotor.

The process needs an initial investment in energy (to make rotor move at 2000m/s tangential velocity) but then this is a free energy generator for all practical purpose. If small variations in efficiency make the rotor lose a bit of velocity, just divert a little more power to the RF amplifier : this is just a regulation problem, there is ample margins to adjust and stabilize around the optimal operating point.

If this consequence is a feature of the Em drive, great. If this is a problem then the problem rests in the initial hypothesis of  "propellantless thrust magnitude at constant power". But we often see by proponents the contradictory position that "of course EM drive respects COE, and somehow at constant power input at some (ill defined) point thrust has to surrender" and that "with that technology we could reach Proxima in less than a century", that later hope being made possible only by breaking COE, that is considering "constant thrust at constant power".

So either "constant thrust at constant power" is true and this is (apparently) breaking COE.
Then let's state it : "This journey to the stars is made courtesy of free energy", and be consistent : stop advocating nuclear power generators as Em drive tech could then be self powering.

Or either "constant thrust at constant power" is not true, COE might be preserved, then we would like to see a not so ill defined formula of thrust=function(power, other objective parameters ?), and short of that at least not be sold deep space mission profile that do presuppose constant thrust at constant power, undercover.

BTW "acquired kinetic energy" could by no way be an objective parameter in the mysterious thrust function that would leave COE unscathed, as has been clearly stated above by PPNL about frames, either we have a physical favored rest frame of "something" we are pulling onto, or we don't and "acquired kinetic energy" is going mystical as it depends on arbitrary choice of frame and we know frames are a fiction (even if some are more convenient and look more "natural").

Short journeys to the stars depend on (apparent) COE breaking. No (apparent) COE breaking (ie free or dirt cheap energy), no short journey to the stars. Even if we had an asphalt road to drive on between Sun and Proxima this would be of little help unless there were also cheap gas stations along the way : this is not a problem of shortage of momentum but of shortage of energy.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: RotoSequence on 05/06/2015 02:42 AM
Please forgive the dumb question, but I recall a comment along a similar line of thought before, so I figured I'd ask it here.

Would an imaginary solar-electric vehicle, with imaginary, 100% efficient solar cells and a 100% efficient electrical system, with an arbitrarily high specific impulse (say, Oh My God Particle equivalence) and arbitrarily high propellant reserves attain a final velocity and kinetic energy equivalent to the energy absorbed by the solar cells?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KelvinZero on 05/06/2015 03:22 AM
Please forgive the dumb question, but I recall a comment along a similar line of thought before, so I figured I'd ask it here.

Is it theoretically possible for an imaginary solar-electric vehicle, with imaginary, 100% efficient solar cells and a 100% efficient electrical system, with sufficiently high specific impulse and reaction mass to impart more kinetic energy into the rocket than the equivalent solar flux it used to accelerate?
This probably isn't the question you really meant to ask, or I am reading it wrong, but low ISP is what would allow this, and very easily. If two masses bounce off each other, most of the energy goes into the smaller faster object. A huge amount of light bouncing off you would hardly move you at all, but the same energy could move you quite fast if you were an electric train and could push against the entire earth.

(this is because momentum is conserved (mass*velocity), but kinetic energy is proportional to velocity squared)



Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: vulture4 on 05/06/2015 03:31 AM
If the spacecraft is accelerating (under thrust) it appears the photons approaching the "forward" end of the resonator where they would add momentum in the direction of travel will be redshifted by the acceleration of the resonator to a somewhat lower energy,
http://www.microwaves101.com/encyclopedias/waveguide-mathematics#velocity

Good article on the dynamic Casimir effect. http://arxiv.org/abs/1105.4714
Unfortunately the thrust from this mechanism is less than using the same energy to produce a stream of photons as an exhaust stream.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/06/2015 05:00 AM
If the spacecraft is accelerating (under thrust) it appears the photons approaching the "forward" end of the resonator where they would add momentum in the direction of travel will be redshifted by the acceleration of the resonator to a somewhat lower energy,
http://www.microwaves101.com/encyclopedias/waveguide-mathematics#velocity

Good article on the dynamic Casimir effect. http://arxiv.org/abs/1105.4714
Unfortunately the thrust from this mechanism is less than using the same energy to produce a stream of photons as an exhaust stream.

The Casimir article is confusing in that it talks about a moving mirror. The dynamic Caismir effect depends on an accelerating mirror not just a moving mirror. So if you are thinking of this as propulsion I just don't think so.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: rrb6699 on 05/06/2015 10:47 AM
perhaps I have an idea.  terrestrially, it could be that a method of accumulation of energy build-up could be harnessed.  at some point a power curve would be reached that would allow a controlled release of sufficient thrust to propel.  just a thought ahead.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 05/06/2015 11:22 AM
I'm starting to believe COM, linear and angular, is no longer the brick wall I once thought, especially in the quantum realm:

http://arxiv.org/abs/0803.2811

...from Cornell, and other sources regarding "Transmutation of Momentum"

Way over my humble head: "Transmutation methods are developed for equations of the form x2 φ“ + x2(k2” - q̃(x)) φ = (v2 - (1/4)) φ, with v as spectral variable, which correspond to problems in quantum scattering theory at fixed energy k2 (here v ˜ l + (1/2) with l complex angular momentum). Spectral formulas for transmutation kernels are constructed and the machinery of transmutation theory developed by the author for spectral variable k is shown to have a version here. General Kontrorovič-Lebedev theorems are also proved."

Transmutation via the momentum plane

R. Carroll andD. S. Jones Communicater
Article first published online: 6 JUN 2011
DOI: 10.1002/mma.1670060129
Copyright © 1984 John Wiley & Sons, Ltd

Quantum mechanics can violate conservation of momentum locally but not globally. To see how this works consider the experiments that demonstrated the violation of Bell's inequality. The local measurement of a particle on one end is ruled by probability and can be anything. But when you connect that measurement to the measurement of its entangled twin they must match. That matching is driven exactly by the need to conserve angular momentum. It will do so even if it has to apparently cheat by violating Bell's inequality.

In the matrix mechanics formulation of quantum mechanics that conservation of momentum is built in at the ground level. In fact all the classical conservation laws are built in. In fact all of Newtonian and classical physics is built in on the classical limit. In the wave mechanics formulation it was less clear that conservation of momentum was preserved. It turned out that the two formulations were equivalent.

So if you want quantum mechanics to violate momentum conservation you are out of luck. It is like squaring the circle or trisecting the angle. The math just will not allow it.

Indeed. In fact conservation laws are even more apparent in QM because Noether's theorem becomes a lot more straightforward to use. If the hamiltonian is invariant under say translation symmetries exp(i*p*x), we have exp(-i*p*x) H exp(i*p*x) = H for any x. Taylor expanding the exponentials to first order in x, this must imply pH - Hp = 0. Therefore, the Hamiltonian commutes with  the total momentum operator which means that the latter must be a conserved quantity.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/06/2015 12:31 PM
But while I'm certain the effect is an artifact, if it WERE to be true, the implications would be absurd. Unlimited energy (and yes, I know people try to tack on energy conservation whenever someone points it out,....

@Robotbeat.  Serious question for you.  You've mentioned several times that a working EMDrive would be an unlimited energy device.  I don't follow your logic though.  The EM drive converts electromagnetic input energy into output kinetic energy at some efficiency yet to be discovered, minus friction and other parasitic factors.  How does that make a free energy device?  Are you suggesting that it converts at greater than 100%?  How so?

I think what Robotbeat is referring to has to do with differences in kinetic energy. To double the velocity of an object takes four times the energy. However, many EM drive theories state that to double the velocity of an object only takes double the energy. So, you use the EM drive to increase the velocity, then use a normal system to convert the KE into heat for your heat engine, and you get extra energy from nowhere, free energy.

If your theory gets you free energy it is wrong.

Maybe something interesting and useful is going on in these devices, but it isn't going to throw away the past hundred years of physics.

Here is a concrete contraption to get unlimited energy, and unlimited deltaV, given the hypothesis of constant "propellantless thrust" at constant power :
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=619550;image)
bigger (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=619549;image)

Em drives mounted on a rotor turning at 2000m/s tangential velocity (not easy but this is the kind of tangential velocity attained in some energy storage flywheels...). Em drives consuming 1kW microwave, radiating some (all ?) of this power as heat and thrusting at 1N : 1N/kW is in the ballpark of what has been experimentally claimed already. This gives 2000m/s * 1N = 2kW mechanical power to the shaft of the rotor. 2kW mechanical power at the shaft are converted to 1800W DC current by a generator (and 200W radiated as heat). Of this 1800W DC electrical power, 250W are diverted for any use we like. To keep it in line with the topic I put it to good use to power another Em drive but really we are free to use those 250W for whatever (creating mass for instance). The power splitter is not 100% efficient, it radiates 50W of power. 1800-250-50 = 1500W to feed the RF amplifier. The RF amplifier wastes (radiates) 500W as heat and pumps 1000W of clean microwave back into the Em drives on the rotor.

The process needs an initial investment in energy (to make rotor move at 2000m/s tangential velocity) but then this is a free energy generator for all practical purpose. If small variations in efficiency make the rotor lose a bit of velocity, just divert a little more power to the RF amplifier : this is just a regulation problem, there is ample margins to adjust and stabilize around the optimal operating point.

If this consequence is a feature of the Em drive, great. If this is a problem then the problem rests in the initial hypothesis of  "propellantless thrust magnitude at constant power". But we often see by proponents the contradictory position that "of course EM drive respects COE, and somehow at constant power input at some (ill defined) point thrust has to surrender" and that "with that technology we could reach Proxima in less than a century", that later hope being made possible only by breaking COE, that is considering "constant thrust at constant power".

So either "constant thrust at constant power" is true and this is (apparently) breaking COE.
Then let's state it : "This journey to the stars is made courtesy of free energy", and be consistent : stop advocating nuclear power generators as Em drive tech could then be self powering.

Or either "constant thrust at constant power" is not true, COE might be preserved, then we would like to see a not so ill defined formula of thrust=function(power, other objective parameters ?), and short of that at least not be sold deep space mission profile that do presuppose constant thrust at constant power, undercover.

BTW "acquired kinetic energy" could by no way be an objective parameter in the mysterious thrust function that would leave COE unscathed, as has been clearly stated above by PPNL about frames, either we have a physical favored rest frame of "something" we are pulling onto, or we don't and "acquired kinetic energy" is going mystical as it depends on arbitrary choice of frame and we know frames are a fiction (even if some are more convenient and look more "natural").

Short journeys to the stars depend on (apparent) COE breaking. No (apparent) COE breaking (ie free or dirt cheap energy), no short journey to the stars. Even if we had an asphalt road to drive on between Sun and Proxima this would be of little help unless there were also cheap gas stations along the way : this is not a problem of shortage of momentum but of shortage of energy.

@frobnicat: how general are the statements above, concerning the hypothesis of constant "propellantless thrust" at constant power ?

Do they apply for example, to:

1) An idealized military search light used as a photon rocket (assuming, for argument's sake, in a Gedankenmodell that components have an infinite life without degradation, and you operate it an indefinite amount of time with energy supply)

(http://www.cckw.org/weare_2006_083.JPG)

2) Woodward's propellant-less Mach Effect (assuming, for argument's sake, that Woodward's conjecture is valid, and you can operate it an indefinite amount of time with energy supply)

If there are differences that constrain the energy paradox between the above two and the EM Drive, please point out the differences, as it may be instructive for this discussion to unveil these differences regarding what is possible and what is not possible (under conservation of energy and conservation of momentum).

Thanks
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/06/2015 01:37 PM
...

Though, I suppose this discussion isn't about the article, and should go over to the main EMDrive thread...

From one co-author to another co-author of the article   ;)

I argue to keep the energy paradox discussion here, because what appears to bother scientists and engineers the most about the article is whether the article should have had more, stronger skeptical warnings, particularly inserted in the Applications section (that paraphrased Dr. White's previous AIAA papers on constant acceleration at constant power trips to the planets and to Alpha Centauri), concerning the energy paradox  issues.  Conservation of Momentum and Conservation of Energy (both are tied together in the stress-energy tensor in relativity  https://en.wikipedia.org/wiki/Stress%E2%80%93energy_tensor , and are fundamental pillars of physics, from General Relativity to Quantum Mechanics - Ehrenfest theorem - ) is the crux of why the scientific and engineering community is so skeptical of the EM Drive, so, in a sense, the engineering and scientific community has decided that's what the article is about.

So it is healthy to discuss it here  :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: zero123 on 05/06/2015 02:33 PM

Do they apply for example, to:

1) An idealized military search light used as a photon rocket (assuming, for argument's sake, in a Gedankenmodell that components have an infinite life without degradation, and you operate it an indefinite amount of time with energy supply)

A photon rocket does not have this problem because even at its theoretical maximum thrust per power ratio (which is about 3.336 * 10^-9 N/W), the speed it would have to reach in order to start the violation is the speed of light in vacuum. So, even though it has a constant thrust per power input it will simply never reach the required speed no matter what you do.

But any increase in the thrust/power ratio will decrease the speed to something that can be reached and at 1N/kW that speed is only 1 km/s.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sghill on 05/06/2015 02:35 PM
Fair enough Rodal! :)

<soapbox>Though, I think many people who don't follow the threads are missing the background that we wrote the article to summarize the activity and discussions going on in the forum for all of the great readers patient enough to follow along, but for whom the science is sometimes unapproachable. 

Our article went viral. Sobeit. A friend at Boeing emailed me just yesterday to tell me our article came across the internal Boeing news feed to employees, so I'd like to think we struck the right balance between explaining the "what is going on" and "why I should care."  Your complete rewrite of my closing paragraphs were particularly strong while remaining professionally restrained IMHO. :)  The article wasn't meant to be a white paper, but in an information vacuum I guess it filled that roll- if imperfectly.  I also noticed the click-bait articles began appearing the day after Chris announced we were working on an article (about 2 weeks before we released it), so to the people who wrote them who lurk on the forum, I ask you to exercise more care next time.  It does a disservice to the technology and the people exploring it to state: "Did NASA just discover warp technology by mistake?" as your headline.</soapbox>

Having said all that, I think it's super terrific that some new qualified people are now participating in the forum because of the article, and I encourage everyone else who is new to take the time to read all the thread discussions before raising a hand (the Search function works too!), and exercise patience when things get too deep to understand.  It's a rare gift that we all get to see this kind of sausage being made firsthand- especially when the pay-off could be so big.  Let's not ruin it.  And Mr. March, if you're reading this.  Please come back!

I'll just leave it at that...
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/06/2015 02:47 PM

Do they apply for example, to:

1) An idealized military search light used as a photon rocket (assuming, for argument's sake, in a Gedankenmodell that components have an infinite life without degradation, and you operate it an indefinite amount of time with energy supply)

A photon rocket does not have this problem because even at its theoretical maximum thrust per power ratio (which is about 3.336 * 10^-9 N/W), the speed it would have to reach in order to start the violation is the speed of light in vacuum. So, even though it has a constant thrust per power input it will simply never reach the required speed no matter what you do.

But any increase in the thrust/power ratio will decrease the speed to something that can be reached and at 1N/kW that speed is only 1 km/s.

Correct, that is one limit that should be pointed out.  Now, how about the Woodward Mach Effect ?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: hhexo on 05/06/2015 03:43 PM
Hello everybody.
First of all, thanks to all who have made this discussion possible. I think that some good scientific discussion is being done here and in the other EmDrive thread. I have started lurking in this forum two weeks ago when the buzz about the new tests started, but only now I've decided to register and post some comments.

First of all, disclaimer: I am an engineer, not a physicist, but for my degree I had to do several exams to do with electromagnetism and even some quantum-related effects (the ones related to how a semiconductor works). So I have a healthy interest in physics, and I've read more on the matter than just what I studied for the exams, but I am not an expert.

I am perplexed by this paragraph in the article:

In Dr. White’s model, the propellant ions of the MagnetoHydroDynamics drive are replaced as the fuel source by the virtual particles of the Quantum Vacuum, eliminating the need to carry propellant. This model was also met with criticism in the scientific community because the Quantum Vacuum cannot be ionized and is understood to be “frame-less” – meaning you cannot “push” against it, as required for momentum.

I'd like to know more about Dr. White's model than just this description, and I don't know enough about the QV in terms of the complicated quantum mechanics maths, but I can wrap my head around virtual particles. I trust in their existence because they are related to black hole Hawking radiation, and we have observed that radiation. We have a model, and it works.
From what I understand of the model, though, I think I have a further observation about the model of "pushing against the virtual particles" that could lead to an experiment to disprove it.

Suppose you have a fluctuation where a particle-antiparticle couple spawns into existence and then annihilates pretty much immediately, just as in the model for virtual particles; in very simplistic terms (and I'm sure the reality is more complicated) they "borrow" some energy and momentum and "return" it when they annihilate (gah, I know, I'm butchering it, but bear with me). Now suppose that it was possible to "push" that particle-antiparticle pair as reaction mass with some (magic?) apparatus in the time while the pair is briefly in existence. The pair would gain a total momentum p equal and opposite to the apparatus pushing it.
Then the pair annihilates - but wait! Now the two particles have more momentum (and energy) than what they "borrowed" to come into existence. Because of CoM, that extra momentum must go somewhere. It can't just disappear. The system would have to transform in such a way that it's conserved.

The only way I can see this happening is if it is released as radiation (or other by-product particles). We know that radiation has momentum, so this is possible. In other words, a device using the virtual particles as reaction mass would "shine" with some extra radiation that can't be explained in any other way.
This radiation is either massive (i.e. it's made of particles) or massless (i.e. it's light).

In the latter case, energy and momentum for radiation are related by the E = pc relation. If we have measured a momentum variation p in our apparatus, and therefore we have an equivalent momentum variation to be radiated, then the energy released as radiation would be pc, which for any meaningful value of momentum would be utterly huge and it would likely destroy the apparatus. Plus, where is the energy coming from?!?

In the former case, then this extra stream of particles is radiated from the apparatus in such a way that it must be detectable by some experiment. Granted, it might be difficult (it they're neutrinos, we're basically stuffed) but it must be conceptually possible.
We might even be able to estimate a range of bounds for the average total mass generated by this interaction, because for each particle E = mc^2 + pv which can be summed over all the particles, and we know the upper bound of the total E (because of CoE that is at most what energy we pumped into the apparatus as input), the total p (which is equal to the momentum change of the apparatus) and we know that for every massive particle it must be true that 0 <= v < c.

So, I would argue that another objection to the "pushing against virtual particles" model is that since we haven't observed a huge amount of gamma rays melting the lab, then some mass must be created somehow from the expended energy. However it has not been explored in the experiments whether this extra mass was produced (and personally I suspect we won't find it, but that's just my opinion).

Does this make sense?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: john smith 19 on 05/06/2015 04:10 PM
As someone commented about another dispute over the momentum of particles (RV Jones "Instruments & Experiences) "We are in such a state of confusion that we must learn something."  :)

Perhaps it will only be how to build longer lasting magnetrons  :( , perhaps it will open up the solar system.

Time, and more data, will tell.   
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ppnl on 05/06/2015 04:18 PM
Hello everybody.
First of all, thanks to all who have made this discussion possible. I think that some good scientific discussion is being done here and in the other EmDrive thread. I have started lurking in this forum two weeks ago when the buzz about the new tests started, but only now I've decided to register and post some comments.

First of all, disclaimer: I am an engineer, not a physicist, but for my degree I had to do several exams to do with electromagnetism and even some quantum-related effects (the ones related to how a semiconductor works). So I have a healthy interest in physics, and I've read more on the matter than just what I studied for the exams, but I am not an expert.

I am perplexed by this paragraph in the article:

In Dr. White’s model, the propellant ions of the MagnetoHydroDynamics drive are replaced as the fuel source by the virtual particles of the Quantum Vacuum, eliminating the need to carry propellant. This model was also met with criticism in the scientific community because the Quantum Vacuum cannot be ionized and is understood to be “frame-less” – meaning you cannot “push” against it, as required for momentum.

I'd like to know more about Dr. White's model than just this description, and I don't know enough about the QV in terms of the complicated quantum mechanics maths, but I can wrap my head around virtual particles. I trust in their existence because they are related to black hole Hawking radiation, and we have observed that radiation. We have a model, and it works.
From what I understand of the model, though, I think I have a further observation about the model of "pushing against the virtual particles" that could lead to an experiment to disprove it.

Suppose you have a fluctuation where a particle-antiparticle couple spawns into existence and then annihilates pretty much immediately, just as in the model for virtual particles; in very simplistic terms (and I'm sure the reality is more complicated) they "borrow" some energy and momentum and "return" it when they annihilate (gah, I know, I'm butchering it, but bear with me). Now suppose that it was possible to "push" that particle-antiparticle pair as reaction mass with some (magic?) apparatus in the time while the pair is briefly in existence. The pair would gain a total momentum p equal and opposite to the apparatus pushing it.
Then the pair annihilates - but wait! Now the two particles have more momentum (and energy) than what they "borrowed" to come into existence. Because of CoM, that extra momentum must go somewhere. It can't just disappear. The system would have to transform in such a way that it's conserved.

The only way I can see this happening is if it is released as radiation (or other by-product particles). We know that radiation has momentum, so this is possible. In other words, a device using the virtual particles as reaction mass would "shine" with some extra radiation that can't be explained in any other way.
This radiation is either massive (i.e. it's made of particles) or massless (i.e. it's light).

In the latter case, energy and momentum for radiation are related by the E = pc relation. If we have measured a momentum variation p in our apparatus, and therefore we have an equivalent momentum variation to be radiated, then the energy released as radiation would be pc, which for any meaningful value of momentum would be utterly huge and it would likely destroy the apparatus. Plus, where is the energy coming from?!?

In the former case, then this extra stream of particles is radiated from the apparatus in such a way that it must be detectable by some experiment. Granted, it might be difficult (it they're neutrinos, we're basically stuffed) but it must be conceptually possible.
We might even be able to estimate a range of bounds for the average total mass generated by this interaction, because for each particle E = mc^2 + pv which can be summed over all the particles, and we know the upper bound of the total E (because of CoE that is at most what energy we pumped into the apparatus as input), the total p (which is equal to the momentum change of the apparatus) and we know that for every massive particle it must be true that 0 <= v < c.

So, I would argue that another objection to the "pushing against virtual particles" model is that since we haven't observed a huge amount of gamma rays melting the lab, then some mass must be created somehow from the expended energy. However it has not been explored in the experiments whether this extra mass was produced (and personally I suspect we won't find it, but that's just my opinion).

Does this make sense?

I think you have a fair grasp of the problem. The only thing I would add is that it takes a whole lot of energy to produce a tiny amount of mass. The energy needs of the thing would be worse than if you were only producing photons. And you would still burn down your lab with intense radiation. Even if you were producing neutrinos you would have to produce them in such numbers that they would become detectable.

There are actually several experiments being done where a beam of neutrinos are beamed through the earth and detected elsewhere. One of them claimed that the neutrinos were going faster than light but that turned out to be a loose cable.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/06/2015 05:31 PM
Hello everybody.
First of all, thanks to all who have made this discussion possible. I think that some good scientific discussion is being done here and in the other EmDrive thread. I have started lurking in this forum two weeks ago when the buzz about the new tests started, but only now I've decided to register and post some comments.

First of all, disclaimer: I am an engineer, not a physicist, but for my degree I had to do several exams to do with electromagnetism and even some quantum-related effects (the ones related to how a semiconductor works). So I have a healthy interest in physics, and I've read more on the matter than just what I studied for the exams, but I am not an expert.

I am perplexed by this paragraph in the article:

In Dr. White’s model, the propellant ions of the MagnetoHydroDynamics drive are replaced as the fuel source by the virtual particles of the Quantum Vacuum, eliminating the need to carry propellant. This model was also met with criticism in the scientific community because the Quantum Vacuum cannot be ionized and is understood to be “frame-less” – meaning you cannot “push” against it, as required for momentum.

I'd like to know more about Dr. White's model than just this description, and I don't know enough about the QV in terms of the complicated quantum mechanics maths, but I can wrap my head around virtual particles. I trust in their existence because they are related to black hole Hawking radiation, and we have observed that radiation. We have a model, and it works.
From what I understand of the model, though, I think I have a further observation about the model of "pushing against the virtual particles" that could lead to an experiment to disprove it.

Suppose you have a fluctuation where a particle-antiparticle couple spawns into existence and then annihilates pretty much immediately, just as in the model for virtual particles; in very simplistic terms (and I'm sure the reality is more complicated) they "borrow" some energy and momentum and "return" it when they annihilate (gah, I know, I'm butchering it, but bear with me). Now suppose that it was possible to "push" that particle-antiparticle pair as reaction mass with some (magic?) apparatus in the time while the pair is briefly in existence. The pair would gain a total momentum p equal and opposite to the apparatus pushing it.
Then the pair annihilates - but wait! Now the two particles have more momentum (and energy) than what they "borrowed" to come into existence. Because of CoM, that extra momentum must go somewhere. It can't just disappear. The system would have to transform in such a way that it's conserved.

The only way I can see this happening is if it is released as radiation (or other by-product particles). We know that radiation has momentum, so this is possible. In other words, a device using the virtual particles as reaction mass would "shine" with some extra radiation that can't be explained in any other way.
This radiation is either massive (i.e. it's made of particles) or massless (i.e. it's light).

In the latter case, energy and momentum for radiation are related by the E = pc relation. If we have measured a momentum variation p in our apparatus, and therefore we have an equivalent momentum variation to be radiated, then the energy released as radiation would be pc, which for any meaningful value of momentum would be utterly huge and it would likely destroy the apparatus. Plus, where is the energy coming from?!?

In the former case, then this extra stream of particles is radiated from the apparatus in such a way that it must be detectable by some experiment. Granted, it might be difficult (it they're neutrinos, we're basically stuffed) but it must be conceptually possible.
We might even be able to estimate a range of bounds for the average total mass generated by this interaction, because for each particle E = mc^2 + pv which can be summed over all the particles, and we know the upper bound of the total E (because of CoE that is at most what energy we pumped into the apparatus as input), the total p (which is equal to the momentum change of the apparatus) and we know that for every massive particle it must be true that 0 <= v < c.

So, I would argue that another objection to the "pushing against virtual particles" model is that since we haven't observed a huge amount of gamma rays melting the lab, then some mass must be created somehow from the expended energy. However it has not been explored in the experiments whether this extra mass was produced (and personally I suspect we won't find it, but that's just my opinion).

Does this make sense?
If you are interested in Dr. White's conjecture regarding the above, see this:   

https://en.wikipedia.org/wiki/Woodward_effect#Quantum_mechanics

and associated references.   Woodward's Mach-Effect theory predicts a transient (inertial) mass fluctuation that arises according to his transient mass equation.  The NASA Engineer (Paul March) quoted in the NSF article posits that Dr. White's and Prof. Woodward's theories are "two sides of the same coin".  The section of the NSF article dealing with Applications paraphrased numerous previously published papers of Dr. White and Paul March (and other co-authors) to show the motivation for their research.  Unfortunately there was not enough space to objectively, concisely, comprehensively and adequately discuss these conjectures in an article directed towards a larger audience.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: hhexo on 05/06/2015 05:36 PM
The only thing I would add is that it takes a whole lot of energy to produce a tiny amount of mass. The energy needs of the thing would be worse than if you were only producing photons. And you would still burn down your lab with intense radiation.

Well, no, actually, the radiation being massive instead of massless is what saves it from burning the lab. With massive radiation most of the spent energy would go into the creation of mass and you would only get a handful of particles propelled at a high speed, just as in an ion drive. The only difference is that you've spawned the particles out of energy (how? I have no idea - but let's just discuss it).

A quick back-of-the-envelope calculation (in pure engineer style, and pure speculation at this stage)...

Let's suppose we pump a certain amount of energy in our apparatus, and let's suppose that some of it is transferred to the virtual particles, some to the apparatus, and some is dissipated, for CoE.
Suppose we have 100J (e.g. 100W for one second) going into the virtual particles, which then annihilate and the extra 100J is released as massive radiation. We have:

100 = m * c^2 + p * v = m * c^2 + m * v * v = m * (c^2 + v^2)

So, m = 100 / (c^2 + v^2). Generally in these experiments massive particles created this way have a significant velocity... I don't know what they would have in this case, let's pretend it's on the same order of magnitude as c but smaller... let's say 1*10^8 m/s (while c is 3*10^8). The square of c is about 9 times 10^16, the square of v is about 1 times 10^16. So the denominator becomes 10^17 just to make the calculation easier. :)
The generated mass of the massive radiation is in the order of magnitude of 10^-15 kg. Very small, but possibly detectable.

If as we said v = 1*10^8, then the momentum of the massive radiation is of the order of m * v = 10^-7. This is the same momentum gained by the apparatus, which however has a much bigger mass and therefore will gain a much smaller velocity.
However, we also know that the change in momentum is basically the thrust times the time it's been applied for, i.e. delta-p = F * delta-t. Since we suppose that we've pumped our energy all within 1 second, the thrust F would be again of the order of 10^-7 Newtons.

... which is not too distant from the micro-newtons they claim to have measured, actually.  :o
Vary the m and v of the generated massive radiation, and you might be able to fit the data. Maaaybe.

In other words, I think the creation of massive radiation instead of massless radiation might be closer to explaining this (and incidentally it would make this magical apparatus a plain old reaction-mass drive, not "reactionless", therefore avoiding issues with CoM and CoE), but there hasn't been any experiment that demonstrated such additional massive radiation. Nor I can see how the "magic" of mass generation would work.

... can we have an experiment just to check? :)
Personally, I think by now somebody would have detected a stream of particles with 100W of power leaving the apparatus with a momentum bias towards the back... so I'm not hopeful and I remain of the idea that "pushing on virtual particles" is probably the wrong explanation.

Also, somebody (I think in the other thread) mentioned the possibility that EmDrive could be atomizing its own shell and propelling ions just like an ion drive, which would be a much simpler explanation. Again, a massive radiation detector would give some insight on this possibility.

It's all about the experiments, after all.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: hhexo on 05/06/2015 05:38 PM
If you are interested in Dr. White's conjecture regarding the above, see this:   

https://en.wikipedia.org/wiki/Woodward_effect#Quantum_mechanics

and associated references.

Thanks very much for the link! I will definitely look into it.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Chris Bergin on 05/06/2015 08:52 PM
Interesting post from Star One moved - with responses - to the main EM Drive thread per report to mods that it is where this is being discussed, so all in one place:

http://forum.nasaspaceflight.com/index.php?topic=36313.msg1370652#msg1370652
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Carl G on 05/06/2015 11:18 PM
A reminder of the post made by Chris several times, this is not a thread for collecting links of sites that are making a very poor attempt to cover this. This thread is for discussing the article here.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: frobnicat on 05/07/2015 12:12 AM
...
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29276.0;attach=619550;image)

Em drives mounted on a rotor turning at 2000m/s tangential velocity (not easy but this is the kind of tangential velocity attained in some energy storage flywheels...). Em drives consuming 1kW microwave, radiating some (all ?) of this power as heat and thrusting at 1N : 1N/kW is in the ballpark of what has been experimentally claimed already. This gives 2000m/s * 1N = 2kW mechanical power to the shaft of the rotor. 2kW mechanical power at the shaft are converted to 1800W DC current by a generator (and 200W radiated as heat). Of this 1800W DC electrical power, 250W are diverted for any use we like. To keep it in line with the topic I put it to good use to power another Em drive but really we are free to use those 250W for whatever (creating mass for instance). The power splitter is not 100% efficient, it radiates 50W of power. 1800-250-50 = 1500W to feed the RF amplifier. The RF amplifier wastes (radiates) 500W as heat and pumps 1000W of clean microwave back into the Em drives on the rotor.

The process needs an initial investment in energy (to make rotor move at 2000m/s tangential velocity) but then this is a free energy generator for all practical purpose. If small variations in efficiency make the rotor lose a bit of velocity, just divert a little more power to the RF amplifier : this is just a regulation problem, there is ample margins to adjust and stabilize around the optimal operating point.
...

@frobnicat: how general are the statements above, concerning the hypothesis of constant "propellantless thrust" at constant power ?

Do they apply for example, to:

1) An idealized military search light used as a photon rocket (assuming, for argument's sake, in a Gedankenmodell that components have an infinite life without degradation, and you operate it an indefinite amount of time with energy supply)


zero123 concise reply on that (http://forum.nasaspaceflight.com/index.php?topic=37438.msg1370370#msg1370370) is spot on. To make a short story long :

As often remarked : for any propellantless device yielding "given constant thrust for given constant power" (ie. a definite thrust/power ratio) there is a velocity relative to a power feedback loop system above which net power surplus can be generated (indefinitely, wear apart).
This velocity is simply the inverse of the thrust/power ratio : V (m/s) = power (W) / thrust (N).

For a perfect photon rocket, that is indeed a "propellantless device yielding given constant thrust for given constant power" the ratio thrust/power is 1/c, the velocity above which the photon rocket should run relative to a power feedback loop would be c, which it can't. This saves the photon rocket as a theoretically correct device, which is fine for the current frameworks since it is also experimentally proven.

Side note 1 : I have also often seen 2*power/thrust as the velocity above which propellantless devices start to exhibit COE issues. This is the value that is given when comparing the acquired kinetic energy relative to "start frame" (inertial rest frame of the device just when switched on) taking together :
->  Ek = 1/2 * m * V²
->  V = a t
->  thrust = m a
->  Ee = power * t
and equating Ek (acquired kinetic energy) with Ee (expanded energy, used by the drive to do its thrust)
That yields 1/2 * (thrust/a) * V² = power*(V/a) => V=2*power/thrust

This is correct to state that above velocity of 2*power/thrust there is clearly a COE issue, but it is misleading to assume it is a good upper bound, ie. that below that we are "safe" : for a device with 1.99 times the thrust/power performance of a perfect photon rocket, the velocity 2*power/thrust is just a tiny bit above c and can't be reached. That don't prevent such a device to be put to use as a power harvester above  V=power/thrust, just make it spin at 200000km/s tangential speed on the above contraption for instance. Not very practical but still frowned upon in usual frameworks.

In summary : power/thrust is the speed limit, and since apart from c all speeds are arbitrary (depend on arbitrary choice of rest frame, or arbitrarily high tangential speed in above contraption) every "propellantless device" that claims better than 3.33 * 10^-9 N/W  must either come with a hidden energy source to pump, or plainly break COE. And this is from the first second of operation : can't have a tolerance window when Ek<Ee before COE police realise there is a problem and intervene, because Ek is a fiction (depends on arbitrary frame).

Side note 2 :
One may wonder how the above unlimited energy generator scheme would behave with a conventional action/reaction thruster, those being known to have much better than 3.33 * 10^-9 N/W. Since such a reactor needs to expel mass, it needs to be fed mass (otherwise the scheme is no longer "unlimited" as the thruster would deplete quickly). If the mass flow goes through the shaft and is distributed radially to the tangentially mounted thrusters, the apparent "Coriolis forces" acting from the propellant flow on the radial pipes would yield a counter torque of such magnitude that it would keep the energetic cycle below breakeven (or just at breakeven assuming no losses at all, which is impossible). Reality of COE is implacable.

The device depicted above would work as an unlimited energy generator only with a better than photon rocket propellantless drive (given the fact that the Coriolis effect of an energy flow is negligible due to the extreme lightness of energy compared to conventional reaction mass, so to speak, this would need further justification when talking about relativistic conventional action/reaction thruster). Happen to be that this is not only a thought experiment but it becomes a technologically achievable possibility starting at about 1N/kW Em drive (if such a thing exists). Note that I took care of inefficiencies in the feedback cycle (there is some margin). Even more so above the 10N/kW some are dreaming of : an unlimited energy generator then becomes trivial, and with quite a good power/mass ratio at that.

Quote
2) Woodward's propellant-less Mach Effect (assuming, for argument's sake, that Woodward's conjecture is valid, and you can operate it an indefinite amount of time with energy supply)

If there are differences that constrain the energy paradox between the above two and the EM Drive, please point out the differences, as it may be instructive for this discussion to unveil these differences regarding what is possible and what is not possible (under conservation of energy and conservation of momentum).

Thanks

There is no difference of consequence : with a better than photon rocket propellantless drive at hand, there is an unlimited energy generator possible, at least in principle, and in practice starting at above 1N/kW (steady state, or averaged steady state). This derives directly from the phenomenology of the device, not its operating principle.

The difference being that Woodward theory (and ME thruster assumed principle) posits an exchange of energy/momentum with rest of the Universe (past and future), the energy problem gets "diluted" to the horizon of it all, kind of. So, some proponents of ME thrusters seem less reluctant to state explicitly, on some forum, that the device is indeed a cheap energy harvester (and that operating could be accelerating the demise of reality BTW, and that dark energy is the signature of all people, past and future, using ME thrusters on cosmic scales). My knowledge of GR is way too feeble to tackle seriously the pros and contras of "Mach principle" and derived Woodwards works, but my gut feeling is not good. Looks like it's just a more sophisticated way to be wrong.

Obviously no one (Woodward, White, Shawyer) wants to make too much publicity about how their drives are good unlimited energy generators, but they all sell those same drives for energetically dirt cheap fast space transportation, which really is the same. Using steady state thrust/power ratio to put forward impressive mission profiles, and failing to say at the same time that those very same steady state thrust/power ratios imply "apparently free energy", is lie by omission. If not outright deceit I dare say when in the same paper the issue of COE is supposedly addressed as an ill defined lowering thrust/power and in the next chapter a constant thrust/power used with no remorse to reach deep space.

Trying to make the propellantless drives to comply with apparent COE yields so much inconsistencies that I'm convinced that, if they are for real (which I'm not convinced), they must indeed be energy harvesters, and COE is to be saved by determining what is (silently) harvested. For White this means altering/lowering the ZPF density (which in principle can't be done since it's already a baseline). Could be detected locally. For Woodward this means imparting some entropy (unsure about that one) on the spatio-temporal walls of reality. Would be hard to prove, but experimental proof of apparently unlimited energy generation from a closed box could be indirect evidence. For Shawyer, propellantless drives do comply with apparent COE, there is therefore nothing harvested (except momentum ?) but as a consequence a lot of inconsistencies.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/07/2015 01:29 AM
I'm confused about something ( o.k. many things). I have now read many articles that say this can't work and is all junk science. It violates COM/COE etc.

But isn't that taking a Newtonian view of something operating at a quantum level? Tunnel diodes have negative resistance, but they are quantum tunneling diodes after all. We have been making tunnel diodes for 50+ years but the logic that says the emdrive can't work, in my mind, says tunnel diodes can't work either.

Am I missing something?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: PushHigher on 05/07/2015 01:53 AM
If you study the shape of the new frustum being used - it basically redirects the photons toward center-line of the spherical end plates.  If a photon bounces say a billion times in the chamber before dissipating into heat - it will eventually focus in on that center-line along with many of the other photons in the chamber.  This is momentum along that axis.  Turning the frustum in any direction would be the 3D equivalent of turning a spinning flywheel - energy loss.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Damon Hill on 05/07/2015 01:53 AM
Tunnel diodes have been in mass production for decades.

Massless propulsion devices, not so much.  If the effect can be reliably duplicated, that may change.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 05/07/2015 02:02 AM
I'm confused about something ( o.k. many things). I have now read many articles that say this can't work and is all junk science. It violates COM/COE etc.

But isn't that taking a Newtonian view of something operating at a quantum level? Tunnel diodes have negative resistance, but they are quantum tunneling diodes after all. We have been making tunnel diodes for 50+ years but the logic that says the emdrive can't work, in my mind, says tunnel diodes can't work either.

Am I missing something?

Quantum mechanics and quantum field theory still has conservation of energy-momentum. As mentioned, it is even more explicit there than in classical physics. Tunnel diodes were a straightforward application of known physics and have no relation to this.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: LasJayhawk on 05/07/2015 02:41 AM
I'm confused about something ( o.k. many things). I have now read many articles that say this can't work and is all junk science. It violates COM/COE etc.

But isn't that taking a Newtonian view of something operating at a quantum level? Tunnel diodes have negative resistance, but they are quantum tunneling diodes after all. We have been making tunnel diodes for 50+ years but the logic that says the emdrive can't work, in my mind, says tunnel diodes can't work either.

Am I missing something?

Quantum mechanics and quantum field theory still has conservation of energy-momentum. As mentioned, it is even more explicit there than in classical physics. Tunnel diodes were a straightforward application of known physics and have no relation to this.

I do understand that, kinda.  :) 

What I am thinking of is the PEPCON explosion in 88. A spark from a welder wound up setting off a million pounds of AP. BOOM! A small energy input released a large amount of stored chemical energy.

If the QV is a large storage of negative energy, I might only need to put a little in to get a lot out?? I didn't put the same energy in as I got out, I just just my small energy to tap a large pile of stored energy. That wouldn't be a violation of COE, would it?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/07/2015 03:59 PM
....

If the QV is a large storage of negative energy, I might only need to put a little in to get a lot out?? I didn't put the same energy in as I got out, I just just my small energy to tap a large pile of stored energy. That wouldn't be a violation of COE, would it?
Good point.  My understanding is that @frobnicat attempts to address that with what he calls "Harvesting" energy from the Quantum Vacuum or "Harvesting" energy from the universe in Woodward's formulation.

Quote from: frobnicat
Trying to make the propellantless drives to comply with apparent COE yields so much inconsistencies that I'm convinced that, if they are for real (which I'm not convinced), they must indeed be energy harvesters, and COE is to be saved by determining what is (silently) harvested. For White this means altering/lowering the ZPF density (which in principle can't be done since it's already a baseline). Could be detected locally. For Woodward this means imparting some entropy (unsure about that one) on the spatio-temporal walls of reality. Would be hard to prove, but experimental proof of apparently unlimited energy generation from a closed box could be indirect evidence.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: sanman on 05/09/2015 03:28 PM
You mean accelerating the "heat death" of the universe? Who cares - we'll all be long dead before that happens.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KelvinZero on 05/09/2015 10:45 PM
If true, wouldn't this degrade the universe by using up a finite resource?

Perhaps other advanced species figured this out at some point, and hense a solution to the Fermi paradox!
There is another way this could explain the fermi paradox.

Interstellar travel is hard, even with free energy. Free energy implies free mass. Why not just build more places to live right here? there is plenty of spare space. Growth is now exponential. Any group that shuns this technology will simply be outcompeted. However exponential growth always reaches a limit. In this case it will happen when the mass in your vicinity makes the escape velocity to any other galaxy exceed the speed of light.. crunch. ;)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: maciejmarosz on 05/09/2015 10:51 PM
IN 2012 Poland I made test

Exist three types EM drive

http://2.bp.blogspot.com/-XOxE9OYcVys/VP1HK3fFPgI/AAAAAAAACQc/EnJXXu4d2lg/s1600/CIMG3541.JPG


EM presure has got Si Units

http://2.bp.blogspot.com/-C1cgolGV6r0/VUCw2IWncwI/AAAAAAAACWQ/8RhssZGNGKA/s1600/22.JPG


1 Type 1 (closed chamber )

http://3.bp.blogspot.com/-nCDH5-n3VTU/VT2AQ_J2eBI/AAAAAAAACV8/RuuDYzzBh3s/s1600/11.png

http://4.bp.blogspot.com/-WTceRhi-hIU/VUG8UhWdZ_I/AAAAAAAACWk/Tbv1iX73BFA/s1600/22.JPG



2 Type 2 ( open chamber - designed by Marosz Me )

http://1.bp.blogspot.com/-spFELf_xcJ0/U_CBPKLmCEI/AAAAAAAAB5M/FfYELmw3M6c/s1600/pytanie1.jpg



3 TYpe 3 ( dynamic )

http://2.bp.blogspot.com/-tw7h9kfZcf0/VBk0W5TEt6I/AAAAAAAAB_o/aoG9y_DNPs0/s1600/CIMG3331.JPG




I made in home many tests
BR
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/10/2015 02:05 AM
....
If true, wouldn't this degrade the universe by using up a finite resource?

Perhaps other advanced species figured this out at some point, and hense a solution to the Fermi paradox!

http://www.scientificamerican.com/article/how-wind-turbines-affect-temperature/
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/11/2015 04:53 PM
Good post about shooting out tachyons. 

Concerning  the above-referenced posts in a blog, it is full of insults and name calling, but devoid of substance not already known by scientists and engineers.  Same arguments were made much more succintly in the NSF article (conservation of momentum, that the Quantum Vacuum is inmutable and not degradable, etc.).

In contrast to the insults in that blog post, which never bothers to offer a scientific explanation for the measurements (except non-scientific arguments like "it could be a mosquito"), I worked out the following detailed explanation as a thermal buckling artifact, (which contains equations instead of insults):

https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT

Concerning the EM Drive thread, even the tachyon comment discussed above was previously posted in the EM Drive thread by @frobnicat who also has worked tirelessly to objectively address the experimental measurements and the paradoxes that accompany the EM Drive.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Jared on 05/11/2015 06:04 PM

https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT


As an observer, I have been taking huge interest in the ongoing discussion for the last couple of weeks. I am deeply convinced that the discovery of even the slightest possibility of feasible and realistic interstellar superluminal travel would profoundly and positively alter our species' trajectory. Thus, I want to thank all of you for investing so much in this slight chance.

However, Dr. Rodal's paper seems to effectively end these investigations with respect to the EM Drive, as it makes a lot of sense with a very strong argument.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Rodal on 05/11/2015 06:39 PM

https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT


As an observer, I have been taking huge interest in the ongoing discussion for the last couple of weeks. I am deeply convinced that the discovery of even the slightest possibility of feasible and realistic interstellar superluminal travel would profoundly and positively alter our species' trajectory. Thus, I want to thank all of you for investing so much in this slight chance.

However, Dr. Rodal's paper seems to effectively end these investigations with respect to the EM Drive, as it makes a lot of sense with a very strong argument.
Thanks. But not the end I'm afraid, as buckling is very sensitive to initial imperfections, and hence unlikely to affect all experiments in the same direction.  There are other mechanisms that could explain the measurements.

Thus the thread, as well as life goes on. 

Hopefully such discussions will lead us to find the truth, and if we don't get there, at least they are fun  :)
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Jared on 05/11/2015 07:31 PM
Thank you for your further explanation! :) So I am looking forward to all future developments regarding conjectures, theories and tests.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/11/2015 07:45 PM
If these drives do work I'd put reasonable money that they turn out to be obtaining all the rules just that they are doing it in a very novel & subtle way. It's probable our current prospective that's wrong.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/13/2015 08:13 AM
EM Drive X-Prize Planning thread here at NSF:
http://forum.nasaspaceflight.com/index.php?topic=37563.0

http://www.xprize.org/about/what-is-an-xprize

We've been asked to help develop the challenge design.

What better way to spur development of such a high risk/high reward endeavor? An XPRIZE.

Interested teams who compete have quite a challenge ahead.
1) Prove the reports of anomalous thrust are genuine.
2) Contribute something new to the current state of the art.

Needless to say, those who are successful stand to benefit immensely, simply by leading from the front.

Even if there is ultimately no success, there is still immense value associated with applying lessons learned.

A nice rundown here about the history of spurring innovation:
http://www.washingtonpost.com/wp-dyn/content/article/2010/12/31/AR2010123104063.html

Positive coverage of this effort, links back to EM Drive X-Prize Planning thread (http://forum.nasaspaceflight.com/index.php?topic=37563.0)
http://www.examiner.com/article/a-x-prize-competition-for-nasa-s-impossible-em-drive

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ThereIWas3 on 05/13/2015 11:30 PM
The judging panel must include a profession stage magician. Some extravagant claims in the past have been debunked this way, because they see things that observing physicists have missed.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Misha Vargas on 05/14/2015 12:55 AM
The judging panel must include a profession stage magician. Some extravagant claims in the past have been debunked this way, because they see things that observing physicists have missed.

No, stage magicians are useful for catching deliberate fraud. The tiny effects are more easily explained by small unanticipated (but conventional) forces.

These guys at NASA are not Uri Geller. They're independently testing a design.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: ThereIWas3 on 05/14/2015 01:54 AM
If there is xprize money at stake, the possibility of fraud is there.  Not from NASA but from independent "researchers" who may come out of the woodwork.   
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Ben the Space Brit on 05/14/2015 08:42 AM
For the second time in two weeks, the Daily Mail is reporting on EM Drive (http://www.dailymail.co.uk/sciencetech/article-3080846/Fly-moon-FOUR-hours-British-scientist-says-s-secret-Star-Trek-s-wrap-speed.html).

This second article is pretty much a summary of the principles of the concept and the objections raised against it in pure layman's terms. The overall tone is neutral (with a gleeful hint of 'who knows what else THEY aren't telling us!').

Still, It's odd that the DM should report on this twice in such quick succession. The first article was, oddly enough, heavily drawn from the threads here on NSF. I'm wondering if the Rothschilds (who ultimately own Associated Newspaper Group) may have invested some cash in EMDrive and are trying to talk it up.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/14/2015 10:33 AM
From tabloid:
Quote
Claimed it could fly for eons at the equivalent of 450 million miles an hour

Quote
Its inventor calculates that an interstellar probe would take ten years to reach two-thirds the speed of light, which he sees as pretty much the limit of how fast we could practically travel.

Dang that's fast.....guess I missed that source. Like their tone though.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: A_M_Swallow on 05/14/2015 11:17 AM
The Daily Mail article on Mr Shawyer reports

"Its inventor calculates that an interstellar probe would take ten years to reach two-thirds the speed of light, which he sees as pretty much the limit of how fast we could practically travel."

Which is presumably where the "450 million miles an hour" comes from.

Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/14/2015 12:54 PM
The Daily Mail article on Mr Shawyer reports

"Its inventor calculates that an interstellar probe would take ten years to reach two-thirds the speed of light, which he sees as pretty much the limit of how fast we could practically travel."

Which is presumably where the "450 million miles an hour" comes from.

Quote from tabloid:
Quote
When I tracked down Mr Shawyer to his base in Havant, Hants, he said he was pleased Nasa was ‘having fun’ with his creation and felt some vindication after years of scepticism.

Ah I get the source now, they interviewed him in person. Looks like things are looking up and up for Mr. Shawyer now days.

That stuff always happens:
http://en.wikipedia.org/wiki/Semmelweis_reflex
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/14/2015 03:27 PM
I don't know if many of you encountered this kind of debate on other websites in response to this article. It basically ran along the lines of this concept was discovered sometime back and if there was anything in it we would have known by now. The response to that argument either seemed to be well that's it then case closed or it does work & is in use in the classified world already & that's why we don't know.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Hanelyp on 05/14/2015 07:53 PM
Given the known physics this violates the question naturally rises "why didn't we notice anything related to this before?"
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 05/14/2015 08:20 PM
Given the known physics this violates the question naturally rises "why didn't we notice anything related to this before?"

Likely, the effect was so small that no one noticed it before.  In this case, someone was looking for just such a result.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 05/14/2015 08:24 PM
If one were to use an alblative shield of some sort ahead of the probe and a huge solar sail during decelleration, the probe could arrive after achieving nearly 3/4 C, and decellerate enough to make a more leasurely pass through the starsystem.  (Mind you, this also assumes a turn over along the course, in conjunction with the use of the solar sail).
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: tchernik on 05/14/2015 08:28 PM
Given the known physics this violates the question naturally rises "why didn't we notice anything related to this before?"

Likely, the effect was so small that no one noticed it before.  In this case, someone was looking for just such a result.

If you add there likely are material (the internal dielectric) and physical parameter dependencies (e.g. the resonant frequencies dependent on shape) for seeing any thrust, it's not that surprising nobody has seen it before.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: txdrive on 05/14/2015 11:25 PM
Given the known physics this violates the question naturally rises "why didn't we notice anything related to this before?"

Likely, the effect was so small that no one noticed it before.  In this case, someone was looking for just such a result.
Except that the effect isn't small. The force may be small, but the difference to the standing wave pattern necessary to push the cavity with such net force is really huge, the coupling between microwaves and this neo-aether is huge, etc.

Short of having some God of Space Travel who looks for a specific arrangement of metal, you can't have an isolated instance of little thrust from microwaves without causing a major contradiction with highly sensitive, accurate, and very well repeated experiments.

edit: furthermore, NASA's thrust per watt is much closer to zero than to Shawyer's or Chinese, while Shawyer's scatter plot is linear and would predict much higher thrust per watt. So, NASA's results are much more of a (not particularly high quality) falsification than confirmation. The highly accurate and well repeated experiments supporting established physics are within parts per million from one another. edit2: meanwhile these results are not even consistently within parts per ten from one another within a single lab.

There's thousands of experiments (and billions of practical devices) which confirm that microwaves behave in a particular way, all consistent with one another to a very high degree of accuracy - most do not measure forces, but they do measure microwaves directly, and thus any momentum carried by microwaves and any interactions involving microwaves. And there's a handful of results that disagree, which are so inconsistent that each new casts more doubt than support towards the others.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Stormbringer on 05/15/2015 03:37 AM
If one were to use an alblative shield of some sort ahead of the probe and a huge solar sail during decelleration, the probe could arrive after achieving nearly 3/4 C, and decellerate enough to make a more leasurely pass through the starsystem.  (Mind you, this also assumes a turn over along the course, in conjunction with the use of the solar sail).

Assuming that the orbital mechanics work out you should be able to slow all the way in from the stellar pause (what the heck is a helio-pause around another star?) to near the star hook a "u turn" go back out ward hook another "U turn" and deploy the sail again. Rinse and repeat until enough velocity is lost enough to enter orbit. What i am talking about it a magneto-plasma sail powered by a modest sized tank of gas and whatever is powering the primary propulsion system.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: StrongGR on 05/15/2015 12:14 PM
For the second time in two weeks, the Daily Mail is reporting on EM Drive (http://www.dailymail.co.uk/sciencetech/article-3080846/Fly-moon-FOUR-hours-British-scientist-says-s-secret-Star-Trek-s-wrap-speed.html).

This second article is pretty much a summary of the principles of the concept and the objections raised against it in pure layman's terms. The overall tone is neutral (with a gleeful hint of 'who knows what else THEY aren't telling us!').

Still, It's odd that the DM should report on this twice in such quick succession. The first article was, oddly enough, heavily drawn from the threads here on NSF. I'm wondering if the Rothschilds (who ultimately own Associated Newspaper Group) may have invested some cash in EMDrive and are trying to talk it up.

Not such a good article. Emphasis is on warp drive while EM Drive, if ever will work, had nothing to do with that. Eventually ion drive or solar sails are to compare.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: kdhilliard on 05/15/2015 08:06 PM
The Daily Mail article on Mr Shawyer reports

"Its inventor calculates that an interstellar probe would take ten years to reach two-thirds the speed of light, which he sees as pretty much the limit of how fast we could practically travel."

How does he reconcile that with his "because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector"? (#18 in http://emdrive.com/faq.html)

~Kirk
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: A_M_Swallow on 05/16/2015 01:31 AM
The Daily Mail article on Mr Shawyer reports

"Its inventor calculates that an interstellar probe would take ten years to reach two-thirds the speed of light, which he sees as pretty much the limit of how fast we could practically travel."

How does he reconcile that with his "because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector"? (#18 in http://emdrive.com/faq.html)

~Kirk

With no trouble at all. That is why the EM Drive stops at two-thirds of the speed of light.

Similar rules apply to cars, only with lower top speeds.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Raj2014 on 05/16/2015 05:30 PM
What are they planning to do next with the EM Drive?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Mulletron on 05/16/2015 07:21 PM
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268

I'm linking to this because it mentions us, is mostly accurate (not completely) and is fair and balanced. It has lots of quotes from Shawyer himself. The final comment from him about the West has me extremely unnerved.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/16/2015 08:16 PM

http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268

I'm linking to this because it mentions us, is mostly accurate (not completely) and is fair and balanced. It has lots of quotes from Shawyer himself. The final comment from him about the West has me extremely unnerved.

That was posted to the main thread a few days back. It seems a bit of an odd mix material as it sounded like the interview quotes might have been recycled from an article from last year.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Nilof on 05/16/2015 11:28 PM
I'd say both the article above and several of the commenter above clearly have the wrong idea about which Eagleworks project is more likely to pan out into anything.

A warp drive does not break any obvious laws of physics, and is merely an esoteric construct that happens to require yet undiscovered forms of matter, but is clearly allowed by GR if these forms of matter are allowed. The Alcubierre metric is straightforward enough to show up as a source of homework exercises in general relativity courses.

The EM-drive on the other hand does break some rather important laws of physics, and otherwise should set off enough red lights that calling it a cargo cult is warranted.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: KelvinZero on 05/17/2015 02:13 AM
All the warp drives I have heard of concern FTL and allow time paradoxes. There apparently are all sorts of theoretical issues (eg energy conditions, whatever they are) with negative mass and paradoxes are probably an indication of trying to do something silly.
http://en.wikipedia.org/wiki/Negative_mass

Interestingly if you only warp space with positive mass you could travel approaching lightspeed for no cost... for example if there was a big rod-shaped cloud of dark matter between here and alpha centauri you would gain great speed falling into it and slow down at the other end.

Also the fact that we can imagine sending a digital description of ourselves and a machine reconstructing a copy at the other end makes it clear that physics does not exclude the basic concept of travel at light speed in some more analog fashion.

I have often thought that these sort of non-causality-violating ideas are highly underrated. I mean they would still be amazing while not containing glaring indicators that they have codependent relationships with unicorns.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/17/2015 11:10 AM
I'd say both the article above and several of the commenter above clearly have the wrong idea about which Eagleworks project is more likely to pan out into anything.

A warp drive does not break any obvious laws of physics, and is merely an esoteric construct that happens to require yet undiscovered forms of matter, but is clearly allowed by GR if these forms of matter are allowed. The Alcubierre metric is straightforward enough to show up as a source of homework exercises in general relativity courses.

The EM-drive on the other hand does break some rather important laws of physics, and otherwise should set off enough red lights that calling it a cargo cult is warranted.

I wonder if people even know what that phrase "cargo-cult" means as the way it's banded about would seem to indicate they don't especially in application to this topic.

It's fair enough to criticise the whole endeavour but at least do it in appropriate terms.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Raj2014 on 05/17/2015 02:00 PM
Assuming the EM drive has passed peer review and has had many tests done to verify it works. What will be the next step?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: kdhilliard on 05/17/2015 04:29 PM
With no trouble at all. That is why the EM Drive stops at two-thirds of the speed of light.

Similar rules apply to cars, only with lower top speeds.

I don't think you're following me.

Shawyer's FAQ (http://emdrive.com/faq.html) #18 deals with terrestrial applications:
Quote
The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.

The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.

Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

This reduction in specific thrust is important to public acceptance of Shawyer's claim because otherwise his device would be more easily recognized as a free energy machine.  His attempt to enforce energy conservation is not invariant under Galilean transformation (more on that in a later post), but that's a point lost on the layman who doesn't understand the issues raised by a reactionless drive.

What we should all be asking after reading this interview is, if specific thrust drops so rapidly upon acceleration along the thrust vector that his proposed flying car (http://emdrive.com/terrestrialapplications.html) can be levitated by EmDrive but requires auxiliary engines for propulsion, then how is it able to accelerate a spacecraft to 2/3 c in 10 yr.?  Let's crunch some numbers and figure out what kind of power density he is envisioning for its power source.

He addresses the reduction of specific power (thrust per unit power = T/P) with velocity (due to acceleration along the thrust vector of the EMDrive) starting on page 8 of his Theory Paper (http://www.emdrive.com/theorypaper9-4.pdf).  Combining equation (16) with his formulas for thrust and taking the limit on Q gives (T/P)max < 1 / v, with the maximum specific thrust approaching the inverse of the velocity as Q increases without bound.  Figure 3.2 plots the specific thrust against Q for a velocity of 3 km/s and shows it maxing out at 333 mN/kW.

Assume that our spacecraft of mass m and power P starting from rest is somehow able to achieve its maximum permitted specific thrust at all times.   Combing T/P = 1/v and T = m v-dot (where v-dot = dv/dt, acceleration) yields the differential equation v-dot = (P/m) v-1 with the initial condition v(0) = 0 and solution v(t) = sqrt(2Pt/m).  Plugging in v(10 years) =  2/3 c and solving for power density gives P/m = (2/90) c2 / yr = 63.3 MW / kg.  But that isn't even taking relativity into account.  2/3 c is not highly relativistic, but it does yield a Lorentz factor of 3/sqrt(5) = 1.34, so doing the calculations relativistically reveals a required power density of 97.3 MW / kg.  Accounting for electrical losses, payload, and the mass of the EmDrive itself will further increase the required power density of the spacecraft's power source.

Proponents of VASIMR driven 39 day trips to Mars are rightly taken to task for not pointing out that their plan requires a power source capable of generating an astounding 1 kW / kg.  Shawyer's zero to 2/3 c in 10 years spacecraft needs a power source with five orders of magnitude greater power density.

~Kirk
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Peter Svancarek on 05/17/2015 07:14 PM
With no trouble at all. That is why the EM Drive stops at two-thirds of the speed of light.

Similar rules apply to cars, only with lower top speeds.

I don't think you're following me.

Shawyer's FAQ (http://emdrive.com/faq.html) #18 deals with terrestrial applications:
Quote
The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.

The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.

Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

This reduction in specific thrust is important to public acceptance of Shawyer's claim because otherwise his device would be more easily recognized as a free energy machine.  His attempt to enforce energy conservation is not invariant under Galilean transformation (more on that in a later post), but that's a point lost on the layman who doesn't understand the issues raised by a reactionless drive.

What we should all be asking after reading this interview is, if specific thrust drops so rapidly upon acceleration along the thrust vector that his proposed flying car (http://emdrive.com/terrestrialapplications.html) can be levitated by EmDrive but requires auxiliary engines for propulsion, then how is it able to accelerate a spacecraft to 2/3 c in 10 yr.?  Let's crunch some numbers and figure out what kind of power density he is envisioning for its power source.

He addresses the reduction of specific power (thrust per unit power = T/P) with velocity (due to acceleration along the thrust vector of the EMDrive) starting on page 8 of his Theory Paper (http://www.emdrive.com/theorypaper9-4.pdf).  Combining equation (16) with his formulas for thrust and taking the limit on Q gives (T/P)max < 1 / v, with the maximum specific thrust approaching the inverse of the velocity as Q increases without bound.  Figure 3.2 plots the specific thrust against Q for a velocity of 3 km/s and shows it maxing out at 333 mN/kW.

Assume that our spacecraft of mass m and power P starting from rest is somehow able to achieve its maximum permitted specific thrust at all times.   Combing T/P = 1/v and T = m v-dot (where v-dot = dv/dt, acceleration) yields the differential equation v-dot = (P/m) v-1 with the initial condition v(0) = 0 and solution v(t) = sqrt(2Pt/m).  Plugging in v(10 years) =  2/3 c and solving for power density gives P/m = (2/90) c2 / yr = 63.3 MW / kg.  But that isn't even taking relativity into account.  2/3 c is not highly relativistic, but it does yield a Lorentz factor of 3/sqrt(5) = 1.34, so doing the calculations relativistically reveals a required power density of 97.3 MW / kg.  Accounting for electrical losses, payload, and the mass of the EmDrive itself will further increase the required power density of the spacecraft's power source.

Proponents of VASIMR driven 39 day trips to Mars are rightly taken to task for not pointing out that their plan requires a power source capable of generating an astounding 1 kW / kg.  Shawyer's zero to 2/3 c in 10 years spacecraft needs a power source with five orders of magnitude greater power density.

~Kirk

Shawyers equations are in my opinion rubbish. If you can float a car, that means you can accelerate at the rate of at least 10 m/s^2 (1g is 9.8m/s^2). If you can do this then you can slowly float higher and higher and accelerate as gravity grows weaker and acceleration wouldn't change from 10m/s^2...
2/3c looks like someone doesn't know what it means relative velocity. You can fly 99.99c but you are effectively staying at the same place, unmoving. You can walk around your hypothetical rocket and it would look like it isn't moving at all... You can look at it like the space is moving around yourself.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: kdhilliard on 05/17/2015 09:33 PM
Shawyers equations are in my opinion rubbish. If you can float a car, that means you can accelerate at the rate of at least 10 m/s^2 (1g is 9.8m/s^2). If you can do this then you can slowly float higher and higher and accelerate as gravity grows weaker and acceleration wouldn't change from 10m/s^2...

His distinction between hovering (unlimited) and accelerating horizontally at 9.8 m/s^2 (limited due to reduction in specific thrust) would appear to violate the equivalence principle.

~Kirk
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Peter Svancarek on 05/18/2015 09:13 AM

His distinction between hovering (unlimited) and accelerating horizontally at 9.8 m/s^2 (limited due to reduction in specific thrust) would appear to violate the equivalence principle.

~Kirk

Yeah, and not only that. It is said that mathematics is a servant of physics. But if you instruct your servant poorly, you will end with ill results.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: WBY1984 on 05/22/2015 04:08 PM
Shawyer's a nut. That whole The West is slowly dying, and that's all for the good' business is wild speculation. His math has been shown to be nonesense by many people smarter than him, and the boffins in the other thread are closing in on more conventional and mundane explanations for EMDrive thrust.

End of.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Star One on 05/22/2015 07:31 PM

Shawyer's a nut. That whole The West is slowly dying, and that's all for the good' business is wild speculation. His math has been shown to be nonesense by many people smarter than him, and the boffins in the other thread are closing in on more conventional and mundane explanations for EMDrive thrust.

End of.

What are you defining as mundane?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: cometo on 06/09/2015 03:08 PM

http://2.bp.blogspot.com/-C1cgolGV6r0/VUCw2IWncwI/AAAAAAAACWQ/8RhssZGNGKA/s1600/22.JPG


Your schematic is wrong. If you put 500kg in the 50x side, then you need 500x50 = 25.000 kg in the small jack, not 10 kg.

Regards.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JasonAW3 on 06/09/2015 08:00 PM
Regardless of how one feels about the EM drive, something IS happening, it is repeatable, not only by those who came up with it, but by many others using the same or very similar rigs.  Be it real or some sort of measuring error, calling it some sort of "cargo cult" thing is both misleading, if not more than a bit insulting.

     I don't know what is happening, I know what I hope is happening, but tests thus far have been mostly inconclusive.  If this IS a real phenomena, then I have some ideas, far fetched though they might be, of what MAY be happening, but again, the evidence is inconclusive.

     At worst, one could say I am skeptical, but hopeful.  I am trying to keep an open mind about this, but am tempering it with a large measure of skeptisism.

     If this does turn out to be a real phenomena, then we will have to rexamine some of our fundemental laws of physics, but I'm not quite ready to do that just yet.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: dustinthewind on 06/09/2015 08:05 PM
I'd say both the article above and several of the commenter above clearly have the wrong idea about which Eagleworks project is more likely to pan out into anything.

A warp drive does not break any obvious laws of physics, and is merely an esoteric construct that happens to require yet undiscovered forms of matter, but is clearly allowed by GR if these forms of matter are allowed. The Alcubierre metric is straightforward enough to show up as a source of homework exercises in general relativity courses.

The EM-drive on the other hand does break some rather important laws of physics, and otherwise should set off enough red lights that calling it a cargo cult is warranted.

No real world device breaks the laws of physics.  It obeys the rules of the universe perfectly.  It is only our understanding that is limited.  Therefore we are looking into the physics of it to fully explain what is going on.  Until what is happening can be fully understood "satisfactorily" the search will continue.  If we can understand it in our framework of physics (convection propulsion maybe) then not much will change other than our improved ability to solve problems.  If we can't make a law to explain it then it will remain a mystery to be solved.  If we can explain it via a new hypothesis then it is possible the new hypothesis may become a law over time.  It is also possible a new and useful use of already known physics can be found. 
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: cichy on 07/31/2015 12:54 PM
Are the scientists absolutely sure that the thrust does not come from the interaction between test article and the Earth's magnetic field?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: michael.suede on 11/05/2015 09:28 PM
From the article:

Quote
One possible explanation for the optical path length change is that it is due to refraction of the air.  The NASA team examined this possibility and concluded that it is not likely that the measured change is due to transient air heating because the experiment’s visibility threshold is forty times larger than the calculated effect from air considering atmospheric heating.

This sounds like plasma self-focusing (https://en.wikipedia.org/wiki/Self-focusing).  Someone should look into that.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Trevor Aiden Kirkwold on 02/09/2016 02:18 PM
I'm just a student in high school, but couldn't you possibly apply the Internet of Things to increase efficiency? This, along with an advanced magnetic fusion core, could possibly increase the efficiency of this "warp" drive, couldn't it?

It could also be possible to attach solar glitter "wrapping" in to certain parts of the hull to increase power output.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: D_Dom on 02/09/2016 03:49 PM
Welcome to the forum Trevor! You asked a good question, let me attempt a reasonable answer...
When I think of "internet of things" it breaks down into two distinct areas, sensors and actuators. I want to know what is going on within various areas of interest, be it astronomical, microscopic or somewhere in between. Sensors provide that information. I also want to be able to control various aspects of these interesting areas, sometimes as an experiment when I am not sure of the result, sometimes as part of an industrial process when I know exactly the desired result.
 FYI, I am in the rocket launching business, when I say exactly I mean within "advertised parameters". Say for the sake of argument, a six ton satellite, launched from W-154 degrees on the equator, into a geosynchronous orbital slot one mile wide on E-120 degrees providing coverage of Asia and Australia.
I use a lot of sensors to monitor what is happening during this launch. I use a lot of actuators to control the rocket and ground support equipment. All these systems communicate via computer networks, "the internet of things". For the EM drive experiments it is important to keep in mind we are talking about experiments where the outcome is not well understood. We use various sensors to monitor the experiments in an attempt to better understand the results. We have various control inputs, frequency, power, dimensional aspects of the frustum etc.

I am not sure how you mean to increase power output by applying glitter wrap.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Trevor Aiden Kirkwold on 02/09/2016 05:14 PM
Thank you for welcoming me into the community, I'm terrible at using social media. I see what you're getting at, and you're right on that. For satellites, the Internet of Things would be ideal for control, but with an experimental ship, or other experimental technology, it would be better off with a person controlling it, rather than an automated system.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Trevor Aiden Kirkwold on 02/09/2016 05:20 PM
On the topic of solar glitter, they are, simply put, Glitter-sized Photovoltaic cells that are magnetized. As far as I know, they can be applicable to almost anything, and a pickle jar of these could produce more energy than a normal Industrial solar panel.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Trevor Aiden Kirkwold on 02/09/2016 05:21 PM
Sorry, magnified, not magnetized.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: Trevor Aiden Kirkwold on 02/09/2016 05:25 PM
By the way, I just joined this site today, so I'm brand-new here. Is there a forum somewhere here about possible tests to see if two hydrogen bombs launched directly at each other in deep space might create a star?
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: philw1776 on 02/12/2016 04:23 PM
By the way, I just joined this site today, so I'm brand-new here. Is there a forum somewhere here about possible tests to see if two hydrogen bombs launched directly at each other in deep space might create a star?

No, but anyway nothing like that would happen.  The core of stars has many orders of magnitude of "hydrogen bomb" explosions going off in fractions of a second.
Stars need mass, HUGE amounts, and an H-bomb actually loses mass, the mass it converts to energy. E=MC^2
When the huge amount of mass in a galactic dust & gas cloud compresses because of gravitation, the center creates increasing pressure and temperature that fuses atoms, just like in a H-Bomb.  This fusion continues to "burn" and light up the outer layers of the star which we see.  No fusion at or near the surface, it's all buried in the much much higher pressures and temperatures at the core.
Title: Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
Post by: JohnFornaro on 02/24/2016 02:38 AM
http://www.ibtimes.co.uk/emdrive-warp-drive-are-two-different-things-nasas-still-working-emdrive-1501268

I'm linking to this because it ... has me extremely unnerved.

Yeah, me too, Mull!

"EmDrive is based on the theory of special relativity that it is possible to convert electrical energy into thrust without the need to expel any form of repellent."

Good to know these things... even if one is late to the party!