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'Impossible' EM drive may actually be impossible after all



 
 
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  #1  
Old May 23rd 18, 09:38 PM posted to sci.space.policy
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Default 'Impossible' EM drive may actually be impossible after all

"If something sounds too good to be true then it probably is, so goes the old
saying. And unfortunately, it now seems this is also applicable to the
"impossible" EM drive, first touted over a decade ago as a way to generate thrust
using microwaves, thereby eliminating the need for fuel in deep space exploration.
The initial research caused huge excitement, with scientists venturing it would be
possible to travel from Earth to Mars in just a few weeks if the technology could
be scaled up, but new tests suggest that's unlikely to happen because it doesn't
appear to work at all."

See:

https://www.engadget.com/2018/05/23/...ble-after-all/
  #3  
Old May 24th 18, 11:15 AM posted to sci.space.policy
Jeff Findley[_6_]
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Default 'Impossible' EM drive may actually be impossible after all

In article , says...

On May/23/2018 at 4:38 PM,
wrote :
"If something sounds too good to be true then it probably is, so goes the old
saying. And unfortunately, it now seems this is also applicable to the
"impossible" EM drive, first touted over a decade ago as a way to generate thrust
using microwaves, thereby eliminating the need for fuel in deep space exploration.
The initial research caused huge excitement, with scientists venturing it would be
possible to travel from Earth to Mars in just a few weeks if the technology could
be scaled up, but new tests suggest that's unlikely to happen because it doesn't
appear to work at all."

See:

https://www.engadget.com/2018/05/23/...ble-after-all/

Wow! Who could've guessed ;-)


Shocking, not. An electrodynamic tether will produce a better result
using the earth's magnetic field.

Jeff

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These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #4  
Old May 24th 18, 02:50 PM posted to sci.space.policy
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Default 'Impossible' EM drive may actually be impossible after all

This research report appears to raise more questions.
Why is thrust produced?

Without knowing the interior cavity field that
causes thrust it is impossible to infer the field that
will cause no thrust.

Looking for cable forces is certainly an issue. But
there are no reports of cable force. A cable drive
needs to be tested evidently.
  #7  
Old May 27th 18, 05:41 AM posted to sci.space.policy
Sylvia Else
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Default 'Impossible' EM drive may actually be impossible after all

On 24/05/2018 6:38 AM, wrote:
"If something sounds too good to be true then it probably is, so goes the old
saying. And unfortunately, it now seems this is also applicable to the
"impossible" EM drive, first touted over a decade ago as a way to generate thrust
using microwaves, thereby eliminating the need for fuel in deep space exploration.
The initial research caused huge excitement, with scientists venturing it would be
possible to travel from Earth to Mars in just a few weeks if the technology could
be scaled up, but new tests suggest that's unlikely to happen because it doesn't
appear to work at all."

See:

https://www.engadget.com/2018/05/23/...ble-after-all/


I don't know why so much effort has been put into something for which
there was no credible theory of operation, and no evidence of
significant forces.

There was never any reason to think this thing would work. People whose
inventions require a change in the accepted laws of physics to function
should be expected to provide substantial evidence that those laws are
wrong before anyone else wastes time on it.

Sylvia.
  #8  
Old May 27th 18, 09:10 PM posted to sci.space.policy
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Default 'Impossible' EM drive may actually be impossible after all

If you take an EMdrive cavity and measure the force with a spring
you have an anomaly drive. If you take the cavity and rotate it
180 degrees and still get the same force vector then the cavity
effect is in question.

The report in engadger appears to be cable force speculation as
related to their unstated cable cavity configurations.
  #9  
Old May 28th 18, 03:17 PM posted to sci.space.policy
Jeff Findley[_6_]
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Default 'Impossible' EM drive may actually be impossible after all

In article ,
says...

If you take an EMdrive cavity and measure the force with a spring
you have an anomaly drive. If you take the cavity and rotate it
180 degrees and still get the same force vector then the cavity
effect is in question.

The report in engadger appears to be cable force speculation as
related to their unstated cable cavity configurations.


Engadget isn't that great of a site for space news, IMHO. Here's a
better article at Ars Technica:

SHIELDING?IMPORTANT, MMKAY? ?
NASA?s EM-drive is a magnetic WTF-thruster
Test reveals that the magic space unicorns pushing the EM-drive
are magnetic fields.
CHRIS LEE - 5/21/2018, 12:34 PM.
https://arstechnica.com/science/2018...is-a-magnetic-
wtf-thruster/

The best quote from above is:

"The best part is that the results are the same when the
attenuator is put into the circuit. In this case, there is
basically no radiation in the microwave cavity, yet the
WTF-thruster thrusts on."

So, the German researchers have proven beyond a shadow of a doubt that
the EM cavity has *nothing* to do with the "thrust" since they get the
same "thrust" when replacing the EM cavity with an auttenuator (I'm
guessing essentially a resistor).

This is why the title of the article calls it a "magnetic WTF-thruster".

Jeff
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All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #10  
Old May 29th 18, 05:29 PM posted to sci.space.policy
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Default 'Impossible' EM drive may actually be impossible after all

Early quests for the EMdrive were of a cylindrical cavity
filled with a dielectric coating.

What does it mean when the asymetric EMdrive cavity is a form
of "attenuator also?

Maybe think of the general cavity as containing standing waves.
And some form of waves as causing the noted force? Tuning the power frequency to maximize the percentage of power as standing wave
is a cavity geometry affair.

Power supply interaction with the Earth's magnetic field
certainly needs addressing. See if it will rotate about
like a Ferris wheel. Does the vertical magnetic field vector
alter the performance?

Also why not short the waveguide to look for power supply
effect?
 




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