EMdrive - propulsion system

[Sruk]

Hi!

Please check the following links and write Your opinion on the subject!

http://www.wired.co.uk/news/archive/2014-07/31/nasa-validates-impossible-space-drive

http://www.emdrive.com/

Is this the beginning of an new industrial revolution? Could this be made as a DIY project?

Much oblige!

[lapm]

Well it will be interesting to see if that can be build powerful enough to do some serious maneuvering in space.. Ok, maintaining orbit docent require much thrust, but still...

But isn't this the same virtual force effect physicist see in particle accelerator and they need to system to take that into account?

[Noise Floor]

The NASA technical report is here:

http://arc.aiaa.org/doi/abs/10.2514/6.2014-4029

Unfortunately only the abstract is free, annoying.

[corrado33]

Completely reading the abstract states that even the control test, in which the device was modified to NOT produce thrust, still produced thrust.

That indicates, to me, a problem with the measurement.

When your control produces positive results when you were expecting negative results, you're testing it wrong. Without a stable, predictable, easily measurable control, these results are meaningless.

Nasa already has an "electric propulsion system." Look up info on their ion propulsion research. Sure, it requires a gas to be ionized, but it still provides long lasting continuous thrust that can be used for small satellites. This system, although novel if it works, will not revolutionize the space industry. We already have the capability of exploring every planet and asteroid in our solar system. Beyond that it doesn't matter how much fuel you have, you won't reach it in a very long time.

EDIT: Also, for the record, every "paper" referenced in this article is simply a conference paper, meaning it hasn't completely gone through the rigors of peer review. None of them are actually "published."

[ncoonrod14]

That indicates, to me, a problem with the measurement.

I'm not sure how you come to the conclusion that their measurements are problematic and that this is meaningless... This whole experiment was done because they DONT fully understand plasma thrusters. The fact that they got an unexpected result under controlled conditions shows that there is lots more to learn, not that this pursuit is meaningless! 

if it works, will not revolutionize the space industry. We already have the capability of exploring every planet and asteroid in our solar system.

It won't revolutionize the industry? Since the Model T "had the capability" of transportation I suppose there was no point in the millions of advancements, jobs, and cars since! It's ridiculous to say that since we "have the capability" to explore the solar system that any further advancements wont be revolutionary.

[mikeselectricstuff]

ISTR reading about something like this many years ago, possibly from a "crank inventor" type...?

[corrado33]

I'm not sure how you come to the conclusion that their measurements are problematic and that this is meaningless... This whole experiment was done because they DONT fully understand plasma thrusters. The fact that they got an unexpected result under controlled conditions shows that there is lots more to learn, not that this pursuit is meaningless! 

I won't argue scientific method with you, but without a predictable control, these results ARE meaningless. It's like using a balance and placing a 1 kg reference mass on it and it measuring 1.1 kg. Then measuring something unknown and recording the mass as the true mass.

They literally modified the "device" to not work, aka it was inoperable, nothing special going on, essentially a hunk of metal, and they measured thrust. Then they turned it on and they measured thrust. Hm, no surprise there...

I never said the pursuit is meaningless, I said the results were.

Also for the record, Kerbal space program had this technology implemented long before these "results" came out. 

[ncoonrod14]

I won't argue scientific method with you, but without a predictable control, these results ARE meaningless. It's like using a balance and placing a 1 kg reference mass on it and it measuring 1.1 kg. Then measuring something unknown and recording the mass as the true mass.

I agree that it's fair to rule the results/values they got as meaningless. In addition to what you mentioned, the Chinese measured a similar device and got over 100,000x higher thrust, although everyone seems to agree that their value is highly suspect. I should have clarified that better in that post, oh well. But nonetheless I think what's important here is not that they got 50 micro-newtons of thrust, but the fact that they did have thrust. That is not meaningless.

And actually, the test I mentioned above by the Chinese was completed in mid-2012 if I remember correctly. And having played KSP myself once or twice, the xenon part you're mentioning was first seen in version .18 which was released in December 2012. So if you ask me, I'd say they got the idea from the Chinese! 

[Artlav]

Completely reading the abstract states that even the control test, in which the device was modified to NOT produce thrust, still produced thrust.

Not exactly.
They tested 3 devices - one slotted, one flat (called null test), and one control (just a resistor in the same case).
There were two theories on how it's supposed to work - something about quantum vacuum (Q-drive?), and something about reactionless force (EmDrive?).

One of the theories require slots, so the "null" test was done as the same setup, but without them.

Results?
Both actual ones produced thrust (but different amounts), but the control one - a resistor - didn't.
So, something is going on there, but not what the theories predict.

Considering the scale of the forces involved, anything could have introduced noise into the test, i.e. the fact that it was done in air and not in vacuum.
That's why it needs much more research.

[corrado33]

Not exactly.
They tested 3 devices - one slotted, one flat (called null test), and one control (just a resistor in the same case).
There were two theories on how it's supposed to work - something about quantum vacuum (Q-drive?), and something about reactionless force (EmDrive?).
...

Interesting. I'd love to see the actual text instead of just the abstract. As for the chinese results, coming from someone who has done research in china, I'd be highly suspect of the results. I'm not saying that all results coming out of China are suspect, I'm just saying that there is a reason that reputable scientists (including those in China) don't publish in Chinese journals. If the paper could have stood on it's own and up to peer review, it would have been published in a much more reputable journal, especially since it would be a really big thing if this turns out to be real. Generally what happens with something like this is that they'll submit to a high impact journal, get rejected, then submit to a lesser quality journal to simply publish the paper.

That's my opinion anyway.

And I was wrong, the original chinese paper DID actually get published, in a chinese journal.
Here's a link if anyone wants to read through the translated paper. For the record, it has 15 references, a quick scan tells me that 3 or more of them are from press releases, conference proceedings, and from the author himself.

http://www.emdrive.com/yang-juan-paper-2012.pdf

[Sruk]

Thanks for the Chinese paper.  My goal is to put this news in everyone's ear. Not just the EE's.

Because, if this knowledge get's a way into the DIY communities something great can happen, I'm sure of that.

I wonder, how were people reacting when the steam engine was still in the developing. I'm sure that they couldn't anticipate steam impact on the civilization of that times.

Let me say that I would like to pay for a trip to the Moon or Mars this time next year. 

[corrado33]

I wonder, how were people reacting when the steam engine was still in the developing. I'm sure that they couldn't anticipate steam impact on the civilization of that times.

The only problem is that the steam engine didn't appear to break the laws of physics, and there was an easily observable, working prototype, whereas this "device" currently looks like magic. Apples and oranges my friend.

[Tinkerer]

I wonder, how were people reacting when the steam engine was still in the developing. I'm sure that they couldn't anticipate steam impact on the civilization of that times.

The only problem is that the steam engine didn't appear to break the laws of physics, and there was an easily observable, working prototype, whereas this "device" currently looks like magic. Apples and oranges my friend.

The quote that "suitably advanced technology is indistinguishable from magic" could apply here ya know. The point is dont just dismiss something.
Having said that. If they were expecting one result and got another, that result isnt meaningless. It means they need to go back and look at/modify their setup and then retest.

It will be interesting to see if this goes anywhere but just because it appears to violate something does not mean it does; our knowledge is far from complete. I will reserve judgement on this until more testing is done; beyond just saying its interesting so far.

[pickle9000]

The good thing about science is the ability argue a point. If the test is incorrect we benefit from that by figuring out how to correct it. If there seems to be an unknown phenomena we devise a better test. We win in either case.

[Sruk]

I wonder, how were people reacting when the steam engine was still in the developing. I'm sure that they couldn't anticipate steam impact on the civilization of that times.

The only problem is that the steam engine didn't appear to break the laws of physics, and there was an easily observable, working prototype, whereas this "device" currently looks like magic. Apples and oranges my friend.

You've got my text totally wrong.

The thing I was referring to is the 'spirit of time', "sitz im leben" of NOW. Are we the spectators in the birth of new technology as were people back then. Anyway, if EMdrive fails, so be it, but I hope for the sake of our human race that it won't.

[Alexei.Polkhanov]

Strangely picture in the article with glowing ring looks like one of Soviet/Russian SPT thrusters which they have in production since 1962-1968? and deployed hundreds to keep satellites from falling off the orbit. Pictures themselves published by NASA 

[denelec]

A device that can produce thrust without ejecting matter would be a huge step forward in space propulsion.
With chemical or ion engines, we are limited by the amount of propellant carried by the spacecraft.
An EMdrive coupled with a nuclear generator could produce thrust for decades, opening the way for traveling to the nearest stars.
With chemical or ion engines, we would probably forever be confined to the solar system. 

As for breaking the laws of physics, the laws we know are in constant evolution.
We don't know all the laws of physics and the law we know are probably crude approximations of what's really going on.
In the late 19th century the discovery of radioactivity seemed to violate the then known laws of physics.

Lets keep an open mind.
But as always, extraordinary claims demands extraordinary proofs.  I think more proofs are needed.

[IanB]

A device that can produce thrust without ejecting matter would be a huge step forward in space propulsion.

Such a device already exists. It's called a flashlight.

The photons ejected out the front of the light have momentum and this causes a backwards thrust on the light. Of course the energy carried away by the photons also causes the mass of the flashlight to decrease slightly, so everything is square.

[Alexei.Polkhanov]

Well theoretically space is not a complete vacuum, there could be enough dust and gas in space to generate thrust but you have to push these particles really really really fast.

[denelec]

Such a device already exists. It's called a flashlight.

The photons ejected out the front of the light have momentum and this causes a backwards thrust on the light. Of course the energy carried away by the photons also causes the mass of the flashlight to decrease slightly, so everything is square.

Maybe but the thrust, if any, would be negligible compared to the power used.
A usable device must be capable of converting a good portion of it's electrical power in kinetic energy.

[G7PSK]

Energy and matter are interchangeable well according to Einstein, so ejecting energy in a unified direction must produce some form of reaction however small. At one time chemist shops had an evacuated globe with a vane inside that rotated when sunlight fell on it, that was reaction to energy in the form of light. Light can be considered as either particles or waves and so can RF energy so any microwave dish must produce some thrust  just not enough to start launching space craft though.

[SeanB]

Energy and matter are interchangeable well according to Einstein, so ejecting energy in a unified direction must produce some form of reaction however small. At one time chemist shops had an evacuated globe with a vane inside that rotated when sunlight fell on it, that was reaction to energy in the form of light. Light can be considered as either particles or waves and so can RF energy so any microwave dish must produce some thrust  just not enough to start launching space craft though.

http://en.wikipedia.org/wiki/Crookes_radiometer

[corrado33]

Maybe but the thrust, if any, would be negligible compared to the power used.
A usable device must be capable of converting a good portion of it's electrical power in kinetic energy.

Which is exactly NOT what this thing is doing. I'm sure you'll argue that "well the technology will get better," and (IF IT EVER WORKS) I'm sure it will, but there have been MANY MANY technologies that have fallen significantly short of their expectations. Sometimes, you just can't get it to work well enough to be useful. I'm sure if you look up articles for solar panels when they were first big you'll find ones quoting research projects promising ridiculously high efficiencies.



Until REAL research comes out published in a reputable journal, I will stand here with the majority of rest of the educated scientists in the world and call this device BS. And don't you dare bring up copernicus or any other scientists from back in the day that were prosecuted for their ideas that turned out to be true. We know a lot more now, and religion isn't breathing down the necks of scientists anymore.

[Alexei.Polkhanov]

Hmm Crookes Radiometer does not spin in full vacuum - not enough force. Also effect that we are talking about is exactly reverse - light from the object like Sun pushes other objects away allowing for Solar Sail. In this case object (or spacecraft) itself emitting light.  Yarkovsky effect would describe physical force involved in this case. http://en.wikipedia.org/wiki/Yarkovsky_effect

[IanB]

Also effect that we are talking about is exactly reverse - light from the object like Sun pushes other objects away allowing for Solar Sail. In this case object (or spacecraft) itself emitting light.

Radiation pressure works exactly the same both ways. "Every action has an equal and opposite reaction." If photons hitting an object exert a force on it, then an object emitting photons will experience an equivalent force in the opposite direction.