EMdrive - propulsion system - Page 1
Forum section: electronics / general

author: Sruk
author_rank: Contributor
timestamp: August 04, 2014, 01:06:11 pm
content: 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-drivehttp://www.emdrive.com/Is this the beginning of an new industrial revolution? Could this be made as a DIY project?Much oblige!

author: lapm
author_rank: Frequent Contributor
timestamp: August 04, 2014, 02:22:20 pm
content: 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?

author: Noise Floor
author_rank: Regular Contributor
timestamp: August 04, 2014, 02:26:09 pm
content: The NASA technical report is here:http://arc.aiaa.org/doi/abs/10.2514/6.2014-4029Unfortunately only the abstract is free, annoying.

author: corrado33
author_rank: Frequent Contributor
timestamp: August 04, 2014, 02:35:23 pm
content: 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."

author: ncoonrod14
author_rank: Contributor
timestamp: August 04, 2014, 04:18:47 pm
content: QuoteI'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!QuoteIt 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.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 04, 2014, 04:24:47 pm
content: ISTR reading about something like this many years ago, possibly from a "crank inventor" type...?

author: corrado33
author_rank: Frequent Contributor
timestamp: August 04, 2014, 06:21:57 pm
content: Quote from: ncoonrod14 on August 04, 2014, 04:18:47 pmI 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.

author: ncoonrod14
author_rank: Contributor
timestamp: August 04, 2014, 06:48:56 pm
content: Quote from: corrado33 on August 04, 2014, 06:21:57 pmI 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!

author: Artlav
author_rank: Frequent Contributor
timestamp: August 04, 2014, 08:06:36 pm
content: Quote from: corrado33 on August 04, 2014, 02:35:23 pmNot 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.

author: corrado33
author_rank: Frequent Contributor
timestamp: August 04, 2014, 09:13:35 pm
content: Quote from: Artlav on August 04, 2014, 08:06:36 pmInteresting. 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

author: Sruk
author_rank: Contributor
timestamp: August 04, 2014, 10:18:47 pm
content: 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.

author: corrado33
author_rank: Frequent Contributor
timestamp: August 05, 2014, 03:29:08 pm
content: Quote from: Sruk on August 04, 2014, 10:18:47 pmThe 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.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: August 05, 2014, 04:14:40 pm
content: Quote from: corrado33 on August 05, 2014, 03:29:08 pmThe 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.

author: pickle9000
author_rank: Super Contributor
timestamp: August 05, 2014, 06:04:02 pm
content: 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.

author: Sruk
author_rank: Contributor
timestamp: August 05, 2014, 06:23:40 pm
content: Quote from: corrado33 on August 05, 2014, 03:29:08 pmYou'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.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: August 05, 2014, 06:23:58 pm
content: 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

author: denelec
author_rank: Regular Contributor
timestamp: August 05, 2014, 10:29:13 pm
content: 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.

author: IanB
author_rank: Super Contributor
timestamp: August 05, 2014, 10:54:23 pm
content: Quote from: denelec on August 05, 2014, 10:29:13 pmSuch 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.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: August 05, 2014, 11:25:56 pm
content: 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.

author: denelec
author_rank: Regular Contributor
timestamp: August 05, 2014, 11:36:45 pm
content: Quote from: IanB on August 05, 2014, 10:54:23 pmMaybe 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.

author: G7PSK
author_rank: Super Contributor
timestamp: August 06, 2014, 03:31:36 pm
content: 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.

author: SeanB
author_rank: Super Contributor
timestamp: August 06, 2014, 04:06:17 pm
content: Quote from: G7PSK on August 06, 2014, 03:31:36 pmhttp://en.wikipedia.org/wiki/Crookes_radiometer

author: corrado33
author_rank: Frequent Contributor
timestamp: August 06, 2014, 05:18:08 pm
content: Quote from: denelec on August 05, 2014, 11:36:45 pmWhich 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.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: August 06, 2014, 05:18:45 pm
content: 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

author: IanB
author_rank: Super Contributor
timestamp: August 06, 2014, 05:26:13 pm
content: Quote from: Alexei.Polkhanov on August 06, 2014, 05:18:45 pmRadiation 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.

author: corrado33
author_rank: Frequent Contributor
timestamp: August 06, 2014, 05:26:40 pm
content: Quote from: Alexei.Polkhanov on August 06, 2014, 05:18:45 pmNo, it cannot. That effect comes about because things like asteroids are warmed and cooled by coming in close contact with the sun (or other hot bodies). Photons are emitted anisotropically (not evenly) causing a very small net force. Unless your spacecraft is going to be traveling close to the sun many many times, this effect will have no effect. You'd be better off with a flashlight... At least you can direct that in any direction you want.Heating things takes a ton of energy (queue solar roadways arguments). Heating a rotating something on a satellite will not be efficient.No to mention there is not nearly enough energy available to a satellite outside of our own solar system. Good luck in interstellar space...

author: HP-ILnerd
author_rank: Frequent Contributor
timestamp: August 06, 2014, 08:03:28 pm
content: Quote from: corrado33 on August 06, 2014, 05:18:08 pmQuite so. It appears to be a clear violation of conservation of momentum, despite any protestations of interacting with Quantum media, it's a reactionless drive. I.e., BS.The only real test you can do, is put some solar arrays on it, put it in orbit, turn it on, and if it moves on it's ownwhile not touching anything elseand you can get it toraiseit's orbit by any amount, it works. More likely it'll just float there and make you look silly.Inevitably, upon peer review, this sort of thing will vanish in a puff of experimental error.

author: SeanB
author_rank: Super Contributor
timestamp: August 06, 2014, 08:13:08 pm
content: Slap it in orbit, extend a long rod and charge it up with a set of sharp points at each end to discharge electrons and collect them and you have a motor that uses the earth's magnetic field. Works for doing orbital changes very slowly but no propellant used. Drawback is you can really only move normal to the local field.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: August 06, 2014, 09:43:45 pm
content: Quote from: IanB on August 06, 2014, 05:26:13 pmI would not be so sure that laws of mechanics applicable here exactly. After all photons are said to have zero mass at rest and calculations of momentum created by photon in dielectric material leads to some "controversy"http://en.wikipedia.org/wiki/Abraham%E2%80%93Minkowski_controversy.Actually there is already a Wikipedia article on subject:http://en.wikipedia.org/wiki/Emdrive

author: corrado33
author_rank: Frequent Contributor
timestamp: August 06, 2014, 10:33:27 pm
content: You're sitting here quoting a controversy that has been disproven by the us air force and NASA. (According to the wiki you posted.) Your position is not a strong one.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: August 06, 2014, 10:45:23 pm
content: Hmm, ops, I thought I was one most sceptical among everyone hereWhen did say anything to defend any claims in that article? I just don't think that some of the counter-arguments given here are completely correct either.

author: babysitter
author_rank: Frequent Contributor
timestamp: August 08, 2014, 02:13:04 pm
content: Obviously those readings only show what leaked RF power does to the force sensor front-endbabysitter solution done.