Em drive good news...

[kunok]

The chinese research groups says that the device doesn't work, when they get better instrument the trust disappeared

Source in spanish (the final PS) http://francis.naukas.com/2016/11/06/se-filtra-en-reddit-el-articulo-sobre-emdrive-revisado-por-pares/

paper (the paper and the website is in chinese, i can't get it in the irregular ways...): dx.doi.org/10.13675/j.cnki.tjjs.2016.02.022

[Jonfliesgoats]

The exciting thing about this is that we will either improve instrumentation, improve propulsion or improve our methods.  Great claims require great evidence, but, a good scientist keeps an open mind.  If this thing is generating thrust (which I doubt), perhaps something is happening that we aren't observing?  If the most boring outcomes occur, we still move forward with techniques to isolate propulsion testing from magnetic interference, orientation etc.

Thr ultimate test of this thing would be to fly it, and I think something like that is scheduled to happen.

[Jonfliesgoats]

Also, a lot of intelligent people got excited over pseudo-science, like extra-sensory perception.  The KGB funded studies where they murdered kittens and measured the vital signs of mother cats.  The US spent lots of money trying to have people spot specific targets.  Trained investigators hire psychics to look for bodies.

Whenever we desperately want something like free thrust, the ability to see our enemy's weapons or find a lost kid, we set ourselves up for confirmation bias.

[Aghanim]

1 hour ago, Jonfliesgoats said:

The exciting thing about this is that we will either improve instrumentation, improve propulsion or improve our methods.  Great claims require great evidence, but, a good scientist keeps an open mind.  If this thing is generating thrust (which I doubt), perhaps something is happening that we aren't observing?  If the most boring outcomes occur, we still move forward with techniques to isolate propulsion testing from magnetic interference, orientation etc.

Thr ultimate test of this thing would be to fly it, and I think something like that is scheduled to happen.

Best case scenario: EMdrive actually works, with the effect of revolutionizing space travel, flying cars and ultimately becoming an interstellar civilization, with the unfortunate side effect of blowing all physicist mind, destroying all physics knowledge and books, and a huge threat to everyone in range of mankind because reactionless drive == planet killer done cheap

Worst case scenario: EMdrive does not work, with the effect of improving instrumentation and data processing methodology, with the unfortunate side effect of no flying car and interstellar travel done cheap

Some part of me wants us to explore the stars now, but part of me wants us to well... survive

 

Quote

Ken Burnside said it best.

Friends Don't Let Friends Use Reactionless Drives In Their Universes.

Yeah, I know that the blasted Tyranny of the Rocket Equation ruins science fiction writer's fun by making every gram count. But a Reactionless Drive is a solution that makes even worse problems. Kind of like removing lice by setting your hair on fire.

Sure you'll be giving Tyranny of the Rocket Equation concrete overshoes and dumping it into the ocean. But you will also be giving every space fleet, astromilitary, corrupt corporation, James Bond Villain and little Jimmy in his garage lab access to civilization-destroying relativistic weapons. Are you sure you wanna do that?

And besides, there's the iron-clad Law of Conservation of Momentum which says You Can't Do That. Sure, a future scientific breakthrough might let you have your way, but that's not the way to bet.

Quote

If the EmDrive actually works, it really and truly is a reactionless drive. Which means it is a weapon of mass destruction that would make the Dinosaur-killer asteroid look like a wet fire-cracker.

http://www.projectrho.com/public_html/rocket/reactionlessdrive.php

 

[kunok]

2 hours ago, Aghanim said:

flying cars

That's not expected, the expected trust to weight ratio is ridiculous, as best is like an ion engine without propellant. And the Chinese team already discarded that it works so I won't put any hope in it.

The problem with flying cars is energy density, not the engine.

[p1t1o]

2 hours ago, Aghanim said:

Best case scenario: EMdrive actually works, with the effect of revolutionizing space travel, flying cars and ultimately becoming an interstellar civilization, with the unfortunate side effect of blowing all physicist mind, destroying all physics knowledge and books, and a huge threat to everyone in range of mankind because reactionless drive == planet killer done cheap

Worst case scenario: EMdrive does not work, with the effect of improving instrumentation and data processing methodology, with the unfortunate side effect of no flying car and interstellar travel done cheap

Some part of me wants us to explore the stars now, but part of me wants us to well... survive

 

http://www.projectrho.com/public_html/rocket/reactionlessdrive.php

 

I would split the "best case" scenario into 2:

A) EmDrive works in that it produces thrust without a reaction force, violating current conservation laws.

B) EmDrive works in that it produces thrust, however current conservation laws are preserved. 

There are 2 parts to current research on the drive - whether or not the thrust is real and not just a measurement error, and if there IS thrust, what is the mechanism producing it and does it violate conservation laws.

 

1 minute ago, kunok said:

That's not expected, the expected trust to weight ratio is ridiculous, as best is like an ion engine without propellant. And the Chinese team already discarded that it works so I won't put any hope in it.

The problem with flying cars is energy density, not the engine.

Assuming it works:

100 years ago, jet engines produces terrible thrust, with awful responsiveness, reliability and TWR - If the EmDrive works as some hope, it is reasonable to expect that over the next century, significant improvements in performance will be made. Perhaps not enough to make a flying car, but maybe so.

On another note, a flying car using reaction force as thrust is going to have a significant "danger" area around it on takeoff and landing, a reactionless (or "hidden" reaction) engine might mean you could park your car in your driveway without needing a huge landing pad, cars could pass within feet of each other without getting flung out of the sky by the other cars jetwash etc.

But no, Im not holding my breath either.

[78stonewobble]

7 minutes ago, kunok said:

That's not expected, the expected trust to weight ratio is ridiculous, as best is like an ion engine without propellant. And the Chinese team already discarded that it works so I won't put any hope in it.

The problem with flying cars is energy density, not the engine.

I think the thrust was much much worse than an ion engine, but much better than a pure photon drive. If I remember correctly.

[kunok]

6 minutes ago, 78stonewobble said:

I think the thrust was much much worse than an ion engine, but much better than a pure photon drive. If I remember correctly.

You can get an ion engine operating in that regime, but it's pretty useless, too little trust and would need too much energy IIRC, so an excess mass in the generators that make them inviable.

[DrLicor]

It was measured in a vacuum environment if I'm right. So a sub would give other results. However, scott manley made a video about it:

 

[PB666]

6 hours ago, DrLicor said:

It was measured in a vacuum environment if I'm right. So a sub would give other results. However, scott manley made a video about it:

 

In 100 years the Cannae drive will still produce terrible thrust.

What are we talking about, resonance orbitals and charge repulsion, operating in space. Consider the rate of mass transfer of charge in space per unit time and the scope of a resonance thruster 3.85 Ghz, about 10 cm. Now then square this 0.01 M, this is our scale (meaning we can fathom say 1000 fold increases, but not billions or trillions). Now imagine how much mass/charge passes across that unit of space withing a second.  we are talking ng-ug range even in LEO. And how fast will the drive accelerate these particles in the relevant space.

Eventually Cannae needs to prove itself in space, and there we will see that its prolly just a big resonance orbital creating device that has virtual orbitals that stretch at declining frequencies meters from the thruster at most. The tiny amount of hydrogen/plasma that passes (might even not be of a wavelength that will be accelerated) and basically trivial thrust, with refinement they might get it back to the level of thrust seen in the lab, but certainly not N scale thrust per 0.01 M of thruster cross sectional area.

 

 

 

[p1t1o]

14 hours ago, PB666 said:

In 100 years the Cannae drive will still produce terrible thrust.

What are we talking about, resonance orbitals and charge repulsion, operating in space. Consider the rate of mass transfer of charge in space per unit time and the scope of a resonance thruster 3.85 Ghz, about 10 cm. Now then square this 0.01 M, this is our scale (meaning we can fathom say 1000 fold increases, but not billions or trillions). Now imagine how much mass/charge passes across that unit of space withing a second.  we are talking ng-ug range even in LEO. And how fast will the drive accelerate these particles in the relevant space.

Eventually Cannae needs to prove itself in space, and there we will see that its prolly just a big resonance orbital creating device that has virtual orbitals that stretch at declining frequencies meters from the thruster at most. The tiny amount of hydrogen/plasma that passes (might even not be of a wavelength that will be accelerated) and basically trivial thrust, with refinement they might get it back to the level of thrust seen in the lab, but certainly not N scale thrust per 0.01 M of thruster cross sectional area.

I dunno, considering that we dont know how it works, like at all - or even *if* it works, predictions are hard to credit, but [if it turns out to be a viable thruster] performance will increase over time, that is inevitable. Perhaps flying cars are a stretch though

[hms_warrior]

Just relaying informations from the NasaSpaceflight forum.

http://www.tsijournals.com//articles/directions-for-gravitational--wave-propulsion.pdf

this got posted as a possible trace to chase for explanation.

No Idea if the math is correct but at least the general thesis sounds interessting.

[p1t1o]

16 minutes ago, hms_warrior said:

Just relaying informations from the NasaSpaceflight forum.

http://www.tsijournals.com//articles/directions-for-gravitational--wave-propulsion.pdf

this got posted as a possible trace to chase for explanation.

No Idea if the math is correct but at least the general thesis sounds interessting.

Something about this paper irks me - gravitons? Aren't they a bit old-hat? Generating gravity waves in the laboratory?

 

"The phased array will convert EM radiation at 2.5 GHz to 5 GHz High Frequency Gravitational waves (HFGWs)." - ???

"focusable GW beams" - ??!?

Some *extremely* speculative stuff about dineutrons...

 

On the other hand it might just irk me because the science is way above my pay grade, or just extremely speculative, and Im just embarrassing myself by complaining  

[Green Baron]

Yeah, sounds like magic spells to me :-) Might be my ignorance but i don't even even see a connection to the cavity thruster thing ... ??

 

[p1t1o]

3 minutes ago, Green Baron said:

Yeah, sounds like magic spells to me :-) Might be my ignorance but i don't even even see a connection to the cavity thruster thing ... ??

Potential mechanism? EM waves -> gravity waves -> thrust?

[kunok]

A reddit link discussing to the Chinese investigation : https://www.reddit.com/r/EmDrive/comments/4h8whq/new_emdrive_results_from_professor_yang_in_china/

And we have a link to the paper, is in chinese but the figures are in english.

The abstract

In order to explore the thrust performance of microwave thruster, the thrust produced by microwave thruster system was measured with three-wire torsion pendulum thrust measurement system and the measurement uncertainty was also studied, thereby judging the credibility of the experimental measurements. The results show that three-wire torsion pendulum thrust measurement system can measure thrust not less than 3mN under the existing experimental conditions with the relative uncertainty of 14%. Within the measuring range of three-wire torsion pendulum thrust measurement system, the independent microwave thruster propulsion device did not detect significant thrust. Measurement results fluctuate within ±0.7mN range under the conditions 230W microwave power output and the relative uncertainty is greater than 80%.

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39772.0;attach=1113532

 

[Green Baron]

39 minutes ago, p1t1o said:

Potential mechanism? EM waves -> gravity waves -> thrust?

Uh, I, aeh, see ... :-)

 

This is probably a silly thought, but browsing through the info (without the nasaspaceflight-link because it wants to download a 7.7MB pdf ....) it seems to me that the "thrust" could be a result of electromagnetic fields from the cables. But this would be really silly ... almost like a defect cable that feigns faster than light travel ...

I'm an ignoramus. I need reproductions. Or it didn't happen.

 

[p1t1o]

1 minute ago, Green Baron said:

Uh, I, aeh, see ... :-)

 

This is probably a silly thought, but browsing through the info (without the nasaspaceflight-link because it wants to download a 7.7MB pdf ....) it seems to me that the "thrust" could be a result of electromagnetic fields from the cables. But this would be really silly ... almost like a defect cable that feigns faster than light travel ...

I'm an ignoramus. I need reproductions. Or it didn't happen.

Dont worry it was just a realllllllly long-reaching guess

[monstah]

47 minutes ago, p1t1o said:

Potential mechanism? EM waves -> gravity waves -> thrust?

You forgot "steal underpants" in your logic.

[Superfluous J]

1 hour ago, p1t1o said:

"The phased array will convert EM radiation at 2.5 GHz to 5 GHz High Frequency Gravitational waves (HFGWs)." - ???

"focusable GW beams" - ??!?

Some *extremely* speculative stuff about dineutrons...

What's the problem? Everybody* knows you just need to bounce the dineutrons through a phased array of gravitons, reversing the flux rate at just the right time to produce the thrust.

*At least Geordi LaForge does.

[monstah]

5 minutes ago, 5thHorseman said:

you just need to bounce the dineutrons cross the beams through a phased array of gravitons gate to another dimension, reversing the flux rate polarity at just the right time to produce the thrust total protonic reversal.

Fixed your science for you.

@Green Baron beat me to your 6500th rep  

Edited November 24, 2016 by monstah

[Superfluous J]

Just now, monstah said:

Fixed your science for you.

...

Excuse me, monstah. You said crossing the streams was bad.

[p1t1o]

@5thHorseman @monstah I cant believe you *both* forgot to realign the navigational deflector...

[wumpus]

On 11/23/2016 at 3:04 AM, Aghanim said:

Ken Burnside said it best.

Friends Don't Let Friends Use Reactionless Drives In Their Universes.

The big catch is we know that reactionless drives exist in this universe: put a big old spotlight on the back, and you will generate thrust.  One big difference is that it is fairly easy to note that the momentum changes (due to the doppler effect) as you speed up wrt to outside observer, so it doesn't appear to be capable of perpetual motion.  While Scott Manley posits a "break point" where an em-drive would be capable of such motion (a bit premature since we know even less about why a drive has measured thrust than that it if it has measurable thrust at all), it isn't clear that it wouldn't scale along with relative velocity to have no such break.

The other thing that even if such things exist, right now they have no other use than interstellar probes (and probably a second stage at that).  Ion engines are so more efficient that em-drives are of value only in proving their existence and questioning the importance of momentum (and the conservation thereof*).

Edited November 24, 2016 by wumpus
s/but/put

[p1t1o]

15 minutes ago, wumpus said:

The big catch is we know that reactionless drives exist in this universe: but a big old spotlight on the back, and you will generate thrust.

Are you referring to a photon drive? If so, they are not technically reactionless, conservation of momentum is preserved.