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Old 08-01-2014, 05:24 AM   #1
scc
 
Join Date: Mar 2013
Default [Spaceships] Real Life Non-Super Science Reactionless Engines

From this news article: http://www.wired.co.uk/news/archive/...le-space-drive

For those who don't want to read it, there is are reproducible proof that specific microwaves inside a closed vessel will produce thrust.

Based upon statements in the article about using it on satellites I'd give it the same thrust as an Ion Drive system. TL would be 9, but we COULD make microwaves as far back as WW2, so it could possibly be built earlier then that
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Old 08-01-2014, 06:23 AM   #2
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

This FAQ by the inventor is interesting.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.
Emphasis added

It'll bear a static load, but not accelerate a vehicle. So it's a sort of suspension, not a drive.

Still amazing, though. 30 Newtons per Watt is astounding.
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Old 08-01-2014, 11:20 AM   #3
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

Quote:
Originally Posted by scc View Post
From this news article: http://www.wired.co.uk/news/archive/...le-space-drive

For those who don't want to read it, there is are reproducible proof that specific microwaves inside a closed vessel will produce thrust.
The described setup does not actually prove anything.
Quote:
Originally Posted by http://ntrs.nasa.gov/search.jsp?R=20140006052
....
within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure
....
Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust.
Both of those things are fatal errors. They're getting the appearance of thrust from bad setup, not any real effect.
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Old 08-01-2014, 11:24 AM   #4
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

Quote:
Originally Posted by Anthony View Post
Both of those things are fatal errors. They're getting the appearance of thrust from bad setup, not any real effect.
Having that from NASA seems weird. Genuinely bad experiment control by NASA, or just a badly-written article?
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Old 08-01-2014, 11:39 AM   #5
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

May be an interesting phenomenon anyway. Maybe this will lead the way to something bigger?
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Old 08-01-2014, 11:47 AM   #6
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

Quote:
Originally Posted by vicky_molokh View Post
Having that from NASA seems weird. Genuinely bad experiment control by NASA, or just a badly-written article?
Hard to say, as we can't access the full article (which appears to have actually been a presentation). The two bits Anthony referenced do sound like maybe they could be problematic - microwaves might heat up the sealed container (so we're just looking at a fancy hot-air balloon)*, and the fact they apparently designed a device that wouldn't work, and yet it did implies something screwy is going on in the experiment.

*I assume this is the problem you were referring to, Anthony. I don't really have the physics background to think up any other issue with it being closed and at standard atmospheric pressure (aside from being at atmospheric pressure doesn't lend itself well to figuring out how the device would function in the vacuum of space).
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Old 08-01-2014, 11:52 AM   #7
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

Quote:
Originally Posted by vicky_molokh View Post
Having that from NASA seems weird. Genuinely bad experiment control by NASA, or just a badly-written article?
NASA has actually produced a fair amount of crap, it's not really that shocking (sadly).
Quote:
Originally Posted by Varyon View Post
*I assume this is the problem you were referring to, Anthony.
There are multiple mechanisms that can result in pushing air around (heating or ionization, mostly, but I'm not going to exclude other options without more data), which is why you should test in a vacuum.
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Old 08-01-2014, 12:40 PM   #8
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

This does look a bit like another form of the ion wind effect. I've just glanced at a couple of articles about this, but if it's been tested in an atmosphere I'd guess someone's just reinvented the ionocraft. Again.

I stated out a realistic reactionless drive for GURPS once - 'Realistic' meaning it had the same performance as a pure photon drive. I got something like .0001 or .00001 g (Can't remember exactly offhand) for 6 Power Points, assuming 1 PP represents 50 kw output per ton of spaceship. By that standard 30 Newtons per watt is spectacular.

(Note: Take my estimate for a photon drive with several grains of salt. Math is not my strong point.)
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Old 08-01-2014, 02:34 PM   #9
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

Quote:
Originally Posted by Anthony View Post
Both of those things are fatal errors. They're getting the appearance of thrust from bad setup, not any real effect.
From elsewhere, I've seen it claimed that the 'negative control' there had a change that should have prevented it from working based on a particular theory about how it works, making that not so fatal on an experimental level.

Not having tested in vacuum is a pretty serious flaw though.
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Old 08-01-2014, 02:46 PM   #10
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Default Re: [Spaceships] Real Life Non-Super Science Reactionless Engines

Quote:
Originally Posted by Ulzgoroth View Post
From elsewhere, I've seen it claimed that the 'negative control' there had a change that should have prevented it from working based on a particular theory about how it works, making that not so fatal on an experimental level.
Without more information, it's hard to say, but it makes me inclined to think they've got an instrument error. In any case, the 'negative control' failing most certainly means it's not something that should be published as anything resembling a success.
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