Cannae/EmDrive

[CptRichardson]

Mazon Del, is the thrust in Vacuum-Vacuum case reduced to photon drive? Because this is a hell of an elephant in the room if the thruster only works when filled with gas, or PTFE, which will produce F2 gas under test conditions, which is an even better propellant than air for an ion drive.

It would be highly irritating if that was the case. Then again, even at the current power/thrust ratio it's still doubling the efficiency of any known ion drive, so if it turns out that it's been somehow using any nearby stray atoms as propellant somehow (which would need some explaining, since it's sealed and isn't pumping them through it), it's still one hell of a step up.

[K^2]

Agreed. After we've thoroughly eliminated possibility of errors in measurement, which there is good progress on, the next step should be finding the reaction mass. We know a lot about the exhaust. To generate 50uN at 50W, the exhaust must consist of up to 250ug/s of matter traveling at over 2,000 km/s. The exhaust is likely to be charged, so this shold be quite straight forward to detect with the right equipment. In fact, if exhaust particles are at least as massive as electrons, that's at least 10eV per particle, so a fluorescent screen might be sufficient to detect it.

[DaMichel]

I wonder have they tried running this device for an extended time like a few days without interruption? If the thrust was due to outgassing they would detect changes in thrust as the chamber is filled with the gas, would they?

[sgt_flyer]

The problem, is they only have money for non vaccuum capable components - and those components end up breaking quickly in vaccuum (either explosive decompressions of their capacitors, or difficulties to cool other components in vaccuum (vaccuum being a very good thermal insulator)

[DaMichel]

Oh i see. Well this sucks. I hope they can find some external funding. There has got to be someone foolish adventurous and rich enough to put money into this

[rtxoff]

They really should check out this site, they selling russian vacuum caps for a low price. http://www.sovtube.com/20-vacuum

[Technical Ben]

The problem, is they only have money for non vaccuum capable components - and those components end up breaking quickly in vaccuum (either explosive decompressions of their capacitors, or difficulties to cool other components in vaccuum (vaccuum being a very good thermal insulator)

Is this so? Emphases on this. I've seen things "fly across the room" from "spontaneous failure", and let me tell you, I needed not invoke quantum vacuum as the source of the forces... though it would be helpful to blame for the failure over my own incompetence.

[RuBisCO]

I just notice this, so forgive me, but they more recent claim of 50 micronewtons in hard vacuum using 50 watts, is 1/100 their claimed 0.1 N per 1 Kw... so what went wrong?

[PB666]

The problem, is they only have money for non vaccuum capable components - and those components end up breaking quickly in vaccuum (either explosive decompressions of their capacitors, or difficulties to cool other components in vaccuum (vaccuum being a very good thermal insulator)

Resonating microwaves can also play havoc on the electronics.

For the caps, slow induction of vacuum may help.

For their heat generation devices, the need need to super cool the chamber down and use copper heat transfers to close proximity of the chamber walls.

[N_las]

I just notice this, so forgive me, but they more recent claim of 50 micronewtons in hard vacuum using 50 watts, is 1/100 their claimed 0.1 N per 1 Kw... so what went wrong?

Maybe there newer measurements are a hundred times more accurate? I think the claimed 0.1 N per 1 kW was the number reported by the chinese team.

[sgt_flyer]

Resonating microwaves can also play havoc on the electronics.

For the caps, slow induction of vacuum may help.

For their heat generation devices, the need need to super cool the chamber down and use copper heat transfers to close proximity of the chamber walls.

Yep, i've reread about their problems, and they did use vaccuum proof capacitors when they used vaccuum chamber (before that they used classic electrolytic capacitors which were not vacuum proof)

Seems that what fried their capacitors was corona discharges during the tests.

They really need to find some hardened components capable of withstanding their tests conditions (but i guess it won't come cheap, so no one want to finance them... Snake biting it's own tail

Wonder why there's not more people working on these technologies (at least, there should be people actively trying to debunk it - without recreating their testing conditions, it would be hard to point what they missed which created those positive thrusts (or not, if it's something genuine...))

well, in the end, they'll need to find a way to rule out - and be able to give verifiable proof of these rule outs- of 'classic' known physic forces / interferences which could be at play in their devices -

and then they'll be able quote sherlock holmes 'once we've eliminated the impossible, the remaining answer, however improbable, must be the truth'

After all, no one disproving that their devices did generate some thrust so let's try to rule out all the things we can here on earth - once we could rule all that out - and their devices still provides quantifiable thrust, then we can give it a last test by sending it in space

Now, if we can debunk it, we'll have at least learned something

One of the ways to 'not' make a propellantless vacuum thruster

Edited February 25, 2015 by sgt_flyer

[RuBisCO]

Maybe there newer measurements are a hundred times more accurate? I think the claimed 0.1 N per 1 kW was the number reported by the chinese team.

Perhaps, but here from there webpage they are claiming values as high as hundred of newtons per kw for superconducting models. There lowest model there, the CANNAE Room Temp is producing 86 microN at 50 W which I guess is close.

http://www.emdrive.com/iac2014presentation.pdf

sgt_flyer

Certainly. At least months of continuous thrust in a vacuum chamber would need to be proven before a space bound flight.

Edited February 25, 2015 by RuBisCO

[RuBisCO]

Here a nice video of it "working"

http://emdrive.com/DMtest188.wmv

IMO this is either a total scam or it really works, I think at this point it can't be some kind of experimental error or thermal expansion.

[sgt_flyer]

They reaaaaly are short on money to use a test rig like that Oo

Using a turntable seems not a reliable way to do these kind of tests (although they spoke about a pendulum test in one of the last articles linked here - so this may not be their current test rig)

No wonder they built a ultra low power version, with components not suited for the task (as the kind of hardened components they'll need are very expensive)

[N_las]

I think the video RuBisCo posted is from years ago and does not represent the current tests.

[Nuke]

i was thinking the other day about the feasibility of constructing some of these reactionless engines with hardware already found on board the iss (in apollo 13 co2 scrubber fashion). so that you could simply put it out the airlock and watch what happens. the easiest type of drive to build would probibly be one of those woodward drives. the drive consists of a mechanical oscillator and a capacitor running off of rf power.

so what are things to be found on the iss. certainly there are a lot of laptops and other personal electronics. between official nasa hardware and personal devices, there should be considerable ewaste aboard the iss which can be salvaged for components. laptop mobos are literally littered with switching supply components, oscilators, and other useful parts (also speakers would provide excellent mechanical oscilators) with which to build the rf supplies. you could probibly desolder the parts by simply taking the mobo outside and pointing it at the sun, wait an appropriate amount of time, then have an astronaut/robot tap the back of it and eject the parts into a container.

they have a 3d printer, so could build whatever test/assembly jigs they need and surely they have a tube of epoxy/super glue/bondo floating around up there, and if not there is always duct tape which we all know they have in abundance. not sure if soldering is even possible in microgravity, however nothing prevents you from doing something old skool like wire wrap (of course limited to through hole components).

obviously we need a device that can be built and tested on the ground first with parts available on the iss. i also doubt if nasa would offitially sanction such an experiment, but you might be able to convince an astronaut to build the device in his spare time.

[dharak1]

That would be interesting to talk to the crew about.

Crew member 1: "Darn it just missing a few small caps to get this thing working" "Crew member 2 hasn't been using their laptop recently..."

Crew member 2: " Where the heck is my laptop?" "Hey have you seen it around Crew member 3?"

Crew member 3: "No, sorry, must've floated away and got stuck on some vent."

Crew member 1: "There we go all done"

Crew member 2: "What is that plastic box?"

Crew member 1: "Just a little side project."

*Disassembled laptop gently floats out of Crew member 1's bed closet with an empty roll of duct tape*

Crew member 2: "I'm going to need that box back."

On a more serious note, would astronauts be allowed to de-solder anything in any fashion on board the ISS? Obviously not laptops for work and such but even if they brought their own PCB's and soldering iron would they be able to use it? I know there aren't very many if any AC sources on the ISS because they are all something like 10-24V DC if I remember correctly. Exactly how freely are they allowed to use equipment on the station? I don't think they would get away with using an airlock without being noticed because that would require high up authorization. I know producing a drive would be a free time but team effort.

[Albert VDS]

"Desoldering" a motherboard by placing it outside the ISS is likely to only give you a broke motherboard as the components on it are not rated for a vacuum.

The temperature outside the ISS(what I could find) is about 120 C, unleaded solder melts at 217 C.

So it's not hot enough to desolder the components.

As for actually soldering the parts together, this is what a NASA experiment concluded:

Without gravity, gas bubbles form pores in a soldering joint can reduce its strength. In this experiment, astronauts solder different sets of materials (small wires wrapped with solder in different configurations) while taking video images. By looking at the soldering process and microscopically examining the different samples, it will be possible to determine better methods for soldering in space.

http://www.nasa.gov/mission_pages/station/research/experiments/634.html

This is cool though, Mike Fincke soldering and the rosin spin around the solder:

[Nuke]

i dont think exposing a chip resistor or ceramic capacitor to vacuum will destroy it immediately especially components not currently in operation. electrolytic caps are probibly gonna die though. inductors are going to be fairly usable. still it would probibly be most viable to use ewaste. im sure basic station maintenance produces a lot of this.

i suppose you could theoretically desolder in the cabin. an smd rework station could probibly be operated with both the astronaut and the board restrained. the application of hot air will allow some of the parts to be removed with tweezers (i have one of these and they are quite nifty). for through hole parts you could use a desoldering gun, a hollow tipped iron with a suction system. gonna read that article on reassembly. for an experiment though a few poorly soldered joints are probibly sufficient.

e:

some of those joints look ok considering the gas bubbles forming in the solder. its probibly not a deal breaker. i didnt see any attempts to solder 2 things together though.

Edited February 27, 2015 by Nuke

[magnemoe]

Here a nice video of it "working"

http://emdrive.com/DMtest188.wmv

IMO this is either a total scam or it really works, I think at this point it can't be some kind of experimental error or thermal expansion.

An scam is very unlikely, this is an NASA program who report upward in the system, the scientists will be in trouble later then other tries to replicate it, they also has little to lose if it don't work.

Nobody expect it to work and NASA do lots of other experiments who are more normal like testing heat shield materials who also is assumed to fail.

[cpast]

Is it safe to solder on the ISS? I thought soldering generally had concerns about fumes, which would be bad on the ISS.

[Nuke]

i guess one of the modules has a fume evacuation system. some of the pics also looked like they were working in a plastic glove box of sorts.

[CptRichardson]

Look familiar? Just based off of the design similarities and a few other quirks, I have a feeling that the drive might be some kind of exotic derivitive of an Elf Thruster now that I've seen one.

https://www.aa.washington.edu/research/plasmaDynamics/elf.html

[CptRichardson]

Major Update: They're constructing a 1.2 kilowatt test article to prove or disprove the concept once and for all.

http://nextbigfuture.com/2015/04/magnetron-powered-em-drive-construction.html

It'll take two months to complete, and we can expect results in september to January.

Other bits indicate that the effects of the drive may be related to warp field tests at Eagleworks, citing several interesting readings of the first genuine space-time contractions that show several similar patterns to test runs.

[Scotius]

Wow. Eagleworks recorded first warp-bubbles?!? Holy boosters, Batman - this theory CAN be translated into real deal working thing. Awesome!