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Keith Ness
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Joined: Fri Jun 06, 2014 6:53 am

Re: EmDrive

Unread post by Keith Ness » Mon Dec 12, 2016 3:36 pm

...and my apologies for littering this thread with as much rubbish as I did. As an amateur, I've been very careful in the past about doing research before speaking, but lately I've been slipping up. Hopefully I'll keep my wits more about me going forward.

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Re: EmDrive

Unread post by WLMorgan » Sun Mar 19, 2017 11:18 am

The experiment was badly designed since they had to shoe horn the apparatus into a very small vacuum chamber. That the proximity to the vacuum chamber doesn't affect the experiment is a dubious claim at best. This experiment needs to be performed in space. Perhaps the Chinese will do it.

Their article, published nearly two years ago in a fringe journal, is interesting but it's not clear what bearing it has upon this experiment.

Their error analysis of the experiment is lousy. I calculated their error bars, which are shown in the graph. There is essentially no information in their data. Perhaps with 10x as many measurements they might have something but there's still the issue that it was a badly designed experiment.
calculated error bars (1 sigma) on EM drive experiment
calculated error bars (1 sigma) on EM drive experiment

Keith Ness
Posts: 41
Joined: Fri Jun 06, 2014 6:53 am

Re: EmDrive

Unread post by Keith Ness » Sun Mar 19, 2017 3:31 pm

My eyes are too tired to study this for the time being, but they are on page 165 of thread 9 of the main EmDrive discussion, viewed about a half a million times, over at nasaspaceflight. People are actually independently building and testing models, communicating with the study authors, and travelling to China in that thread...

https://forum.nasaspaceflight.com/index ... 41732.3280

Hopefully someone can someday clue me in to how people read so much video text without going blind... :)

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Re: EmDrive

Unread post by allynh » Fri Nov 03, 2017 12:36 pm

Have physicists finally worked out how NASA's 'impossible' EmDrive propulsion system works?
http://www.dailymail.co.uk/sciencetech/ ... Drive.html
Scientists around the world are working to develop the first ‘reactionless’ propulsion system – a so-called impossible engine that could slash space-travel times and reduce the costs of future missions.

But, many argue a theoretical EmDrive system that uses a microwave field to generate thrust defies the fundamental laws of physics, and could never be brought to life.

New research over the last year, however, now suggests scientists may finally be getting closer to uncovering how the ‘impossible engine’ could work, according to theoretical physicist Giulio Prisco.

The most recent, published by scientists in Portugal, claims a type of ‘pilot wave’ theory could explain the ‘strange’ quantum-like behaviour seen in the experiments.

Scroll down for video

Scientists around the world are working to develop the first ¿reactionless¿ propulsion system ¿ a so-called impossible engine that could slash space-travel times and reduce the costs of future missions. A prototype is pictured
Scientists around the world are working to develop the first ‘reactionless’ propulsion system – a so-called impossible engine that could slash space-travel times and reduce the costs of future missions. A prototype is pictured

The concept of an EmDrive engine is relatively simple.

It provides thrust to a spacecraft by bouncing microwaves around in a closed container.

Solar energy provides the electricity to power the microwaves, which means that no propellant is needed.

The implications for this could be huge. For instance, current satellites could be half the size they are today without the need to carry fuel.

Humans could also travel further into space, generating their own propulsion on the way.

But when the concept was first proposed it was considered implausible because it went against the laws of physics.

Its allegedly fuel-free nature also means the drive may directly contradict the law of conservation of momentum.

It suggests it would produce a forward-facing force without an equal and opposite force acting in the other direction.

In the new study, led by researchers at the University of Lisbon, the team proposes an explanation designed to bridge the gap between quantum and macroscopic systems – a current challenge in the feasibility of the EmDrive.

By the pilot wave theory, bouncing fluid droplets on a vibrating fluid path create what’s known as a pilot-wave field, Prisco explains in an article for Motherboard.

This field then guides the motion of the droplets.

This explanation relies on a nonlinear approach, the authors explain in the study, in which the thrust can be explained as a consequence of the field intensity as it interacts with the particles in the device.

Under the right conditions, such as those in the proposed EmDrive device, the researchers argue that such a system can eschew Newton’s third law, which states that for every action, there is an equal and opposite reaction.

‘Consequently, since we are in the nonlinear realm it may happen that, in general, action does not equal reaction, even taking into account the intermediary of fields,’ the authors argue.

‘This means that in certain specific conditions a minor action may give rise to a huge reaction.’

Over the last few years, researchers have proposed several explanations for the impossible engine, with efforts ramping up after a NASA paper appeared to show scientist had successfully created a working EmDrive prototype.

While some initially cited a ‘quantum vacuum theory’ to explain the findings, others claim a phenomenon known as the ‘Mach effect’ could be to blame.

By this effect, which was first theorized in the 1990s by physicist Jim Woodward, some of the force applied to an accelerating body of mass is stored as potential energy in its body rather than generating kinetic energy, according to Motherboard.


A new propaganda video claims that scientists in China have created a working prototype of the 'impossible' fuel-free engine.

The radical EmDrive has been hypothesised for years by Nasa, but the space agency has been unable to create a working version.

If the physics-defying concept is brought to reality, it's said the engine could get humans to Mars in just 10 weeks.

The video was posted by CCTV.com, and is titled 'Propellantless propulsion: The Chinese EmDrive by CAST scientist Dr Chen Yue, China's Space Agency.'

Is this proof China have cracked Nasa's 'impossible engine'?

It claims that Chinese scientists have developed the EmDrive, and will soon put it into space - although it does not state any technical aspects of the device.

The EmDrive is an engine that provides thrust without the need for fuel.

Instead, it bounces microwaves - provided by solar energy - around in a closed container.

With no fuel to eject, the EmDrive would violate Newton's third law, which states that for every action, there is an equal and opposite reaction.

This isn't the first time that China has claimed to have made a working EmDrive.

This causes fluctuations in the object’s resting mass, and this effect could be harnessed to create the type of thrust seen in the experiments.

Earlier this year, NASA’s Innovative Advanced Concepts (NIAC) program funded a project based on this effect.

And, this summer, a Chinese propaganda video claimed scientists in China have created a working prototype of the ‘impossible’ fuel-free engine.

Despite claims that the device would soon be put into space, the video did not reveal any technical aspects of the system.

In recent tests, NASA scientists managed to generate powers of 1.2 millinewtons per kilowatt (mN/Kw), a fraction of the current state of the art Hall ion thruster, which can achieve a massive 60 mN/Kw (illustrated)
In recent tests, NASA scientists managed to generate powers of 1.2 millinewtons per kilowatt (mN/Kw), a fraction of the current state of the art Hall ion thruster, which can achieve a massive 60 mN/Kw (illustrated)

While the impossible engine remains controversial, experts say it has potential to revolutionize space travel – if it is ever truly brought to life.

‘If the reaction-free EmDrive works, it would open the door for reaction-free space missions, which could reach the planets in weeks instead of months, and at a much lower cost,’ writes

‘It could ultimately open a path to the stars.

‘Therefore, it’s not surprising that visionary engineers continue to pursue the experimental and theoretical EmDrive research, despite the controversial nature of the technology.’

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Location: Japan

Re: EmDrive

Unread post by ja7tdo » Fri Mar 09, 2018 5:28 pm


I think principles of emdrive is electromagnetic mass.

https://translate.google.co.jp/translat ... edit-text=

so , if adding vias voltage to cavity, much thrust power produced.

https://translate.google.co.jp/translat ... edit-text=

also principle of emdrive produce gravity on Earth.

https://translate.google.co.jp/translat ... edit-text=

gravity on Earth is very very complex. who made this system?

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Re: EmDrive

Unread post by allynh » Sun Mar 18, 2018 7:42 pm

In November last year I posted an article from Motherboard about the leaked NASA paper on the EmDrive.


Somebody pointed me to the link of the NASA paper.

Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum

This is the pdf.

These are two papers discussing the EmDrive. They have links and references, so follow up on what is inside if you like.

Overview of the Current State of Understanding of the EMDrive
https://digitalcommons.usu.edu/cgi/view ... t=smallsat

https://www.researchgate.net/profile/Pa ... THEORY.pdf

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Re: EmDrive

Unread post by allynh » Tue May 22, 2018 3:50 pm

A German Team Is Now Trying to Make the ‘Impossible’ EmDrive Engine
https://motherboard.vice.com/en_us/arti ... spacecraft
German physicists launched the SpaceDrive project to explore possible sources of error in EmDrive experiments. Their first experiment identified a possible source of false positives in past successful EmDrive tests.

Since the beginning of the space race over half-a-century ago, humans have walked on the moon and remotely explored the surface of two other planets in our solar system with robots. But so far, only a single spacecraft has made it to interstellar space: Voyager 1, launched in 1977, is currently speeding through the void at a blistering 40,000 miles per hour and covering about 325 million miles per year. Yet even if it was headed in the direction of Alpha Centauri, our closest stellar neighbor, it would take Voyager over 80,000 years to arrive. For a little more perspective on the timescales involved here, 80,000 years ago on Earth the first homo sapiens were spreading out of Africa into Asia.

This is all to say that from a cosmic perspective, Earth is very, very isolated. Perhaps an intuitive idea of this isolation is why our science fiction stories have always been haunted by dreams of interstellar travel, but recently physicists have started to seriously consider how to turn those fictions into reality.

In a paper presented at the Aeronautics and Astronautics Association of France’s Space Propulsion conference this week, a team of German physicists announced SpaceDrive, a research program exploring exotic propulsion mechanisms that they hope will one day make interstellar space travel a reality.

In particular, they described their research results on the EmDrive, a type of “impossible” spacecraft engine that is theoretically able to generate thrust without any propellant. It’s a bit like trying to design a Formula One race car that doesn’t need any gas and is instead powered by the driver pushing on the inside of the windshield. While the researchers didn’t crack the secret to the propellantless-engine, they did manage to create a hypersensitive measurement device and identify sources of possible false positives that will help to better characterize EmDrive experiments in the future.

Read More: The Fact and Fiction of the NASA EmDrive Paper Leak

Normal rockets are limited in their ability to provide interstellar transport because they can’t carry enough fuel to achieve velocities that would make interstellar travel feasible in human time spans. Overcoming the limitations of normal rocket propulsion systems will be necessary for interstellar travel. One leading nonreactive system is being explored by Breakthrough Starshot, which plans to use incredibly powerful lasers to accelerate thumbnail-sized chips to 20 percent the speed of light toward Alpha Centauri. Another strong candidate for nonreactive systems is the EmDrive, which could theoretically be scaled up to propel much larger spacecraft.

The EmDrive concept can be traced back to a paper written by the physicist Roger Shawyer in 2001, but it wasn’t until relatively recently that the idea gained much traction. In 2016, a group of physicists gathered at Estes Park in Colorado to discuss the feasibility of exotic propulsion systems like the EmDrive. Shortly after the meeting, a NASA paper describing an initial successful test of an EmDrive prototype was leaked. Then Chinese state media reported that it, too, had physicists researching these impossible engines who had seen positive results. It wasn’t long before 3D-printed EmDrive prototypes appeared online so that researchers and amateurs could conduct their own EmDrive tests at home.

What was once pure theory seemed to quickly be turning into a feasible reality.

The EmDrive prototype developed by NASA and described in its leaked 2016 paper basically consists of a closed copper cone mounted on an incredibly sensitive pendulum sensor that can detect even the slightest movements. The cone was then placed in a vacuum chamber and its insides were bombarded with microwaves. Incredibly, when these microwaves bounced off the walls of the cone, the pendulum registered a very small amount of thrust that varied with the power of the microwaves supplied to the device. The result was incredible because it appeared to violate the conservation of momentum, a fundamental law of physics that states for every action there is an equal and opposite reaction.

"The issue involved here is whether the experiment is seeing something real or not," Jim Woodward, a physicist at California State-Fullerton and a leading researcher on exotic propulsion mechanisms, told Motherboard after the NASA paper was leaked. "I suspect there may really be something there, but the result they're seeing can't actually be explained in terms of the theory they're proposing. So the question is: what is causing it?"

The researchers themselves broached an explanation that attempts to account for the thrust by invoking pilot wave theory. This theory explains the strange properties of quantum matter (such as entangled particles that can instantaneously influence one another) by suggesting there are ‘hidden variables’ at work that can account for perceived quantum weirdness with regular Newtonian physics—no “ spooky action at a distance” required.

The researcher’s explanation was tentative and didn’t offer a coherent model of exactly how this would work. This led to a flurry alternative explanations including a nonlocal intepretation of pilot wave theory, which keeps quantum effects in the mix, and a theory of radiation pressure posited by Shawyer which claims that microwave radiation puts pressure on the walls of the EmDrive to generate thrust. Woodward, on the other hand, offered up Mach effects as “ the only possible explanation” for the observed thrust.

According to Woodward’s Mach effect theory, when a body of mass is accelerated, some of the force applied to that body does not result in kinetic energy but is stored as potential energy in the body. While the acceleration is changing the internal energy of the body changes as well, which manifests itself as a change in the resting mass of that body. The accelerating body is essentially being squished between the force being applied in the direction of its acceleration and the push back from the rest of the material in the universe via the gravitational field.

Read More: Theoretical Physicists Are Getting Closer to Explaining How NASA’s ‘Impossible’ EmDrive Works

This mass fluctuation effect could account for the thrust observed in NASA’s EmDrive prototype. If the microwaves propagating in the EmDrive cone are applying thrust force to the material that the cone is made of, then you might explain the trust generated this way. “In my view, it’s the only physics that I know and trust to not involve wishful thinking and magical fields,” Woodward told me when we spoke after the NASA leak.

There’s a strong case to be made for Woodward’s Mach-Effect theory, but a far more obvious explanation was that the observed thrust was simply due to an error. In their paper, the NASA researchers strove to eliminate all the major sources of error, such as electromagnetic interference, vibration or thermal expansion of the cone. Still, a team of German physicists are working on a super precise testing facility that will hopefully put to rest the question of whether the observed thrust was just an error.

As detailed in the paper presented by the researchers this week, over the past four years they have designed a sophisticated balance that is placed in a vacuum chamber and measures the movement of an EmDrive prototype using lasers. NASA’s EmDrive only produced a few micro-Newtons of thrust, but this measurement system is able to measure the degree of thrust at a sub-micro-Newton level.

The prototype EmDrive built by the German researchers was a copper cavity with the same dimensions as the prototype tested by NASA in 2016. Although they limited the power supplied to the EmDrive to just 2 watts, their sensors were able to measure roughly 4 micro-Newtons of thrust. Extrapolating from this data, that means that their EmDrive prototype had a thrust-to-power ratio of about 2 milliNewtons per kilowatt, which is almost twice the thrust-to-power ratio achieved at NASA (1.3 milliNewtons per kilowatt).

Yet the German researchers noted that when they changed the direction that the EmDrive was facing, the direction of the thrust changed, but the level of thrust did not, even when the EmDrive was oriented in such a way that any applied power should produce zero thrust.

“This clearly indicates that the ‘thrust’ is not coming from the EmDrive, but some electromagnetic interaction,” the researchers wrote in their paper. “Although we used twisted or coaxial cables as much as possible, some magnetic fields will eventually leak through our cables and connectors.”

When they calculated the forces resulting from a combination of Earth’s magnetic field, the length of their cables and the electric current flowing through them, they found that the result was equal to a few micro-Newtons, which is comparable to the ‘thrust’ they had observed in the vacuum chamber. “We therefore suspect that the interaction of the power feeding for the amplifier with the Earth’s magnetic field masked any real thrusts that could be below our observed value,” they wrote. In a future test, the researchers said they planned to add Mu-metal sheets to the setup that would shield the device from these unwanted outside electromagnetic influences. Yet as they note in their paper, this type of shielding was not used during the NASA experiments.

Although the German researchers did not manage to demonstrate thrust with their EmDrive experiments, they did help identify a possible source of false positives in EmDrive experiments. The researchers acknowledge that it was a “great learning experience with the possibility to find something that can drive space exploration into its next generation.”

Moreover, they managed to create the hypersensitive instrumentation that will likely be necessary to measure the very small amount of thrust that will be produced by these EmDrive prototypes if there is any thrust being produced at all.
The paper is available here.

The SpaceDrive Project - First Results on EMDrive and Mach-Effect Thrusters
https://www.researchgate.net/publicatio ... _Thrusters

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Re: EmDrive

Unread post by WLMorgan » Sun Jun 03, 2018 3:17 pm

from Ars-technica (https://arstechnica.com/science/2018/05 ... -thruster/)

NASA’s EM-drive is a magnetic WTF-thruster
Test reveals that the magic space unicorns pushing the EM-drive are magnetic fields.
CHRIS LEE - 5/21/2018, 10:34 AM

as i stated in March of last year, it was a crappy experiment.

Robertus Maximus
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Re: EmDrive

Unread post by Robertus Maximus » Mon Aug 06, 2018 8:32 am

The Dipole Drive: A New Concept for Space Propulsion

https://www.centauri-dreams.org/2018/06 ... ropulsion/

Dipole Drive or Double Layer Drive?


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