Slashdot Mirror
German Scientists Confirm NASA's Controversial EM Drive
MarkWhittington writes: Hacked Magazine reported that a group of German scientists believe that they have confirmed that the EM Drive, the propulsion device that uses microwaves rather than rocket fuel, provides thrust. The experimental results are being presented at the American Institute for Aeronautics and Astronautics' Propulsion and Energy Forum in Orlando by Martin Tajmar, a professor and chair for Space Systems at the Dresden University of Technology. Tajmar has an interest in exotic propulsion methods, including one concept using "negative matter."
Well NADA is an unlikely source for scams and it doesn't fit the pattern. The science behind it is openly shared without any secret sauce claims. The physics are uncontroversial.
The only thing there could be scam in is whether our engineering can really cash in on it.
At it's best its also not claimed to provide much thrust. You can't leave earth with it. But once you do even a tiny bit of thrust goes a long way. It's not even the only known way to get thrust without fuel - solar sails do that too.
I never got why so many people are so sceptical of this one. Engineering scams are nothing new but this breaks every pattern and the science is genuinely sound.
Unicode killed the ASCII-art *
What more do I need to say?
I'm very hopeful this works. It's easy to be cynical, so I won't say "meh it's all bullshit!" Still, I won't be convinced until I see it provide thrust in a vacuum, away from Earth's magnetic field. It's still far, far too likely it's pushing off something terrestrial. So I'll give them a healthy "go, team, go!"
That said, quoth the article:
"This is the first time that someone with a well-equipped lab and a strong background in tracking experimental error has been involved, rather than engineers who may be unconsciously influenced by a desire to see it work," notes Wired referring to Tajmar's work.
I don't know about that. He is a real professor at a real university, but he also has filed for a patent on a gravity generator, using a process no one has duplicated. Somebody who thinks they've got a gravity generator, but gosh just can't prove it to everybody else, is definitely somebody who may be "unconsciously influenced by a desire to see it work."
We don't have a state-run media we have a media-run state.
In the conclusion section:
The nature of the thrusts observed is still unclear. Additional tests need to be carried out to study the magnetic
interaction of the power feeding lines used for the liquid metal contacts. Our test campaign can not confirm or refute
the claims of the EMDrive but intends to independently assess possible side-effects in the measurements methods
used so far. Nevertheless, we do observe thrusts close to the magnitude of the actual predictions after eliminating
many possible error sources that should warrant further investigation into the phenomena. Next steps include better
magnetic shielding, further vacuum tests and improved EMDrive models with higher Q factors and electronics that
allow tuning for optimal operation. As a worst case we may find how to effectively shield thrust balances from
magnetic fields.
something with a very long, low-thrust burn such as DS1's ion propulsion* and enough fuel to run for half a century maybe, Voyager 1 left the Sun's influence last year - nothing launched from Earth will ever catch it using gravity assists. New Horizons might be travelling at twice the speed of Voyager right now but it's not even 40AU out, by the time it gets to apoapse it'll be travelling slow enough to drop back - it's in a 100AU heliocentric orbit.
*the Dawn spacecraft, currently in orbit around Ceres, also uses ion propulsion - the same NSTAR 2100W engine as DS1, in fact.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
Tajmar made a lot of hoopla over ten years ago about making gravitomagnetic waves orders of magnitude more powerful than GR predicted; some were claiming we were on our way to artificial gravity or a warp drive by his bold claims. Of course, his experiments could never be duplicated. Since then, he's been trying to make waves (ha!) with other dubious claims of making gravity effects by electromagnetic means and such.
Take anything he claims "confirmed" with a one hundred pound bag pinch of salt.
Ion thrusters still consume raw materials, so there's a finite fuel supply. If this does literally turn electricity into thrust without consuming anything then running out of reaction-mass is no longer an issue, and some probes could even be entirely solar powered.
Do not look into laser with remaining eye.
Neither Newton's nor Einstein's theory of gravitation were greeted with "extreme skepticism" by the general community.
Bad example. Light does exert radiation pressure, yes - but it is far, far too weak to drive a radiometer. The spinning radiometer isn't due to radiation pressure. It's a more mundane effect: Imperfect vacuum. The black side is warmed more than the white, which heats up adjacent air, which exerts higher pressure, causing the spin. It's just a plain old heat engine.
An ion thruster is a very efficient reaction mass based thruster,
It still has to drag all that reaction mass along, despite it's only real purpose being that it's thrown out like garbage just to provide thrust.
It takes thrust to push that reaction mass around the place, up until you actually throw it out the window, which is actually out the directed nozzle or whatever.
And what happens when you run out of reaction mass? You have no more thrust.
On the other hand, if you have a reactionless thruster, as long as you provide it with power, it will give you thrust. Slap on solar panels, or if it's a deep space mission, nuclear batteries or the like, and you are set.
As an added bonus, you can use that constant acceleration trick to really build up some speed. Something you can't do with reaction mass because you don't ever have enough, even for a tiny trip like to the moon.
The physics are most certainly NOT uncontroversial.
If this thing were to truly work, it would have insane implications to some basic assumptions about the universe - namely about the very laws of physics themselves.
This device working means that the laws of physics do vary by translation, which goes against every single other observation ever made. The science behind it is most certainly not clearly sound. Skepticism is the only logical option for this thing.
Scientists Confirm 'Impossible' EM Drive Propulsion
Science News, Space / July 27, 2015 / by Giulio Prisco/
Later today, July 27, German scientists will present new experimental results on the controversial, "impossible" EM Drive, at the American Institute for Aeronautics and Astronautics' Propulsion and Energy Forum in Orlando. The presentation is titled "Direct Thrust Measurements of an EmDrive and Evaluation of Possible Side-Effects."
Presenter Martin Tajmar is a professor and chair for Space Systems at the Dresden University of Technology, interested in space propulsion systems and breakthrough propulsion physics.
A Revolutionary Development for Space Travel
The EM Drive (Electro Magnetic Drive) uses electromagnetic microwave cavities to directly convert electrical energy to thrust without the need to expel any propellant. First proposed by Satellite Propulsion Research, a research company based in the UK founded by aerospace engineer Roger Shawyer, the EM Drive concept was predictably scorned by much of the mainstream research community for allegedly violating the laws of physics, including the conservation of momentum.
However, NASA Eagleworks – an advanced propulsion research group led by Dr. Harold G. “Sonny” White at the Johnson Space Center (JSC) – investigated the EM Drive and presented encouraging test results in 2014 at the 50th Joint Propulsion Conference.
White proposes that the EM Drive’s thrust is due to virtual particles in the quantum vacuum that behave like propellant ions in magneto-hydrodynamical propulsion systems, extracting "fuel" from the very fabric of space-time and eliminating the need to carry propellant. While a number of scientists criticize White's theoretical model, others feel that he is at least pointing to the right direction. The NASASpaceFlight website and forums have emerged as unofficial news source and discussion space for all things related to the EM Drive and related breakthrough space propulsion proposals such as the Cannae Drive.
Shawyer has often been dismissed by the research establishment for not having peer-reviewed scientific publications, but White and Tajmar have impeccable credentials that put them beyond cheap dismissal and scorn. Physics is an experimental science, and the fact that the EM Drive works is confirmed in the lab. "This is the first time that someone with a well-equipped lab and a strong background in tracking experimental error has been involved, rather than engineers who may be unconsciously influenced by a desire to see it work," notes Wired referring to Tajmar's work.
Hacked has obtained a copy of Tajmar's Propulsion and Energy Forum paper, co-authored by G. Fiedler.
"Our measurements reveal thrusts as expected from previous claims after carefully studying thermal and electromagnetic interferences," note the researchers. "If true, this could certainly revolutionize space travel."
"Additional tests need to be carried out to study the magnetic interaction of the power feeding lines used for the liquid metal contacts," conclude the researchers. "Nevertheless, we do observe thrusts close to the magnitude of the actual predictions after eliminating many possible error sources that should warrant further investigation into the phenomena. Next steps include better magnetic shielding, further vacuum tests and improved EMDrive models with higher Q factors and electronics that allow tuning for optimal operation."
Contrary to sensationalist reports published by the sensationalist press, the EM Drive is not a "warp drive" for faster than
There's no place I could be, since I've found Serenity...
It cannot be incomplete, it is a purely mathematical statement.
Particularly, for linear momentum, conservation of linear momentum is equivalent to the laws of physics being symmetric by translation.
If linear momentum is not conserved, the laws of physics are not the same throughout the universe and vice-versa.
Thank you for enlightening me. I read the wikipedia page on radiometers: https://en.wikipedia.org/wiki/...
I learned that radiometers do NOT work by "light pressure" which was Crooke's, the inventor's, hypothesis. Radiometers do NOT spin in a perfect vacuum. The two mechanisms that explain why they spin were proposed by the likes of Einstein (relativity guy), Maxwell (equations guy), and Reynolds (number, not aluminum, guy).
But I'll still be willing to listen to reasonable follow-up experiments instead of dismissing out of hand. So we get to Martin Tajmar and his claims (also not peer reviewed, but at least it's at a conference). Tajmar is not the guy I'd choose as the most reputable source. He has a history of claims about...creative physics from poor experimental setups. That is, he claims to observe new physics, but people have consistently had a hard time reproducing his results. Go ahead and google the guy.
I did, and appearantly it was Martin Tajmar himself, who found the flaw in his gravitational gyroscope thesis, and published it: FiberOpticGyroscope Measurements Close to Rotating Liquid Helium. So whatever you think about the guy, a superficial Google result seems to put him at least as honest. If he makes a mistake, he is able to admit it.
Here is the first page of the actual paper, including the abstract which says:
Our test campaign can not confirm or refute the claims of the EMDrive but intends to independently assess possible side-effects in the measurement methods used so far.
So the /. title says pretty much the exact opposite of what the actual
paper says.
I am still extremely skeptical that there is any actual effect. They powered their device with a 700 watt magnatron and measured plus or minus 20 micro-newtons of thrust. To put this in perspective, one Newton is roughly the weight of an apple near the surface of the Earth. If the thrust scales linearally with input power then you would need 50,000 x 700 Watts = 35 Megawatts to levitate a single apple. Of course the inventor claims that the thrust to power ratio is highly non-linear so at these higher power levels you would get a lot more thrust. I have not seen any sensible theoretical model that explains why this would be so.
If you are using hundreds of watts to produce a handful of micro-newtons then it is extremely likely there is no actual effect and what is being measured is just some form of noise. This is especially true when the so-called effect violates a primary law of physics.
We don't see the world as it is, we see it as we are.
-- Anais Nin
People are so sceptical of this one because if true the implications are universe-shaking. It would completely overturn not just modern physics but all of physics since Newton. The claim is that the device violates conservation of momentum. Then via Noether's theorem this implies that the laws of physics are not independent of location in space. (Alternatively, the device is creating a beam of hard to detect particles via some completely unknown but low energy mechanism.)
Also, the device was first designed using a provably incorrect analysis - an analysis using standard physics determined that the device would produce thrust without reaction mass, violating conservation of momentum. As all the standard physics used in the analysis conserves momentum, the analysis must be incorrect. If someone adds up many even numbers and comes up with an odd total, we know they have made a mistake, even without examining their calculations to find out where. This case is exactly analogous. So if this device really does violate momentum conservation, it is a complete and utter fluke, and not by design.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Looking at this another way:
When LHC were looking for the Higgs boson - a particle entirely expected by modern physics - they required a five sigma signal before they were satisfied that they had really found something.
This is a result not only entirely unexpected, but contradictory to almost all known physics. A two sigma (NASA) and three sigma (Germany) signal is not remotely enough to be convincing. At best it is convincing enough for someone to spend the money to further and better test it.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Except it doesn't. The microwaves are not emitted anywhere. They are generated into a sealed chamber. There's nowhere they can go.
The formulae you listed would be useful to describe thrust from a photon drive (or light drive), but those need an open-ended emitter. Also, the results you get from them are about three orders of magnitude too low for the observed ratio of thrust to power. A 700W microwave photon drive wouldn't be detectable by the experimental apparatus.
There's no place I could be, since I've found Serenity...
Photons have no rest mass. Their mass is entirely their energy. They do have mass.
This isn't new. They had to correct for Pioneers microwave thrust. Heat thrust is the accepted explanation for the Pioneer anomaly.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'