Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 2166213 times)

Offline Mulletron

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http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608

I believe the series of successful vacuum tests negates the need for a smoke stick test. Comments?
Challenge your preconceptions, or they will challenge you. - Velik

Offline Mulletron

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Also I want to make sure this is corrected:

I was recently quoted above, yet I do not recall making any such statements which consisted of only 4 periods.... nor did I abruptly end my sentence with the word "shapes."

I will remove this post when I am properly quoted in full or the offending post is removed.

....

A) We should make an effort to properly characterize Finite Element solution packages like COMSOL that are able to obtain solutions to a large number of physical problems.  COMSOL is not just a "wrench" but a whole tool box of solutions.

 
the utility of COMSOL in figuring out this problem is limited as COMSOL is considering the standing wave and isn't considering the traveling wave. It gives no consideration to what is happening over extended time (over multiple full cycles) or to what is happening to a resonant cavity under dynamic operation, for example while under acceleration. COMSOL provides no insight as to what is happening when the resonant cavity is being excited by FM or other sources of phase noise. Building off the comments about COMSOL's ability to simulate mode shapes
Challenge your preconceptions, or they will challenge you. - Velik

Offline Flyby

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Update on the replication attempt.

I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.

If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs. 

https://goo.gl/Q3jGN1

Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf

Just a wild idea, but have you considered this form of powering :
http://en.wikipedia.org/wiki/Wireless_power

basically, contact-less induction would give you frictionless movement (except for the bearing friction and air resistance) and provide power. I'm however not sure what the electromagnetic implications would be on any surrounding devices...(fe, does it act as a magnetic brake?)

Secondly, not sure what would be needed to feed 1Kw of power. It might be not so practical all together...

Although.... I've seen street based induction plates for loading batteries of electric cars.

well.. it's just a wild idea flare... :)
« Last Edit: 05/10/2015 04:39 PM by Flyby »

Offline deltaMass

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Well, although my first two thrust scenarios (trash Noether, trash Einstein) generated a fair amount of discussion, my third thrust scenario went down like a lead balloon, despite it being based on an actual video (Shawyer) and an actual theory (McCullough). Could this be because it forecast so little propulsive utility?   ???

I do hope that's not the reason, else objectivity is being lost here.

I might be wrong about this third scenario too. I am uneasy about the final consideration re. what happens when the power is removed. I see a possibility of exploitation of an agglomerative thrust effect via some sort of pulsed operation. But currently it's just a twinkle in the eye. Or that I fell asleep in a hot tub Friday night and have not been quite right since :)

Offline Rodal

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The only tests reported for an EM Drive in a partial vacuum, have, to my knowledge, been conducted with a bi-layer copper/glass-fiber-reinforced-epoxy base plate with the reinforced epoxy exposed to the vacuum.

Partial vacuum tests do not address the issue of outgassing from the reinforced-epoxy exposed to the vacuum. 

Therefore, it would be wise to address the possible issue of outgassing in such experiments.
« Last Edit: 05/10/2015 04:54 PM by Rodal »

Offline Notsosureofit

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Not a single thing I built defied the laws of physics or the formulas of the trade. . . Maxwell, Ohms law, etc. If something didn't work for some weird reason, it still followed the basic laws and formulas when it ended up.
It doesn't really matter to me what is happening inside of the EM Chamber it must follow the principals of physics and conservation of energy and momentum is one of them. If I have a Air Tank pressurized with 200psi of air and a audio speaker inside that can blast at 100 watts any frequency range no matter what mixture of sound or what mixture of harmonics I crank, the tank will not move, but put a hole in one end and stand back. The second law of thermodynamics states that the entropy of an isolated system never decreases and the EM Chamber is an isolated enclosed system, we think.  If we are getting thrust that, thrust must be acting outside the chamber in some form. This is why I asked the simple question if smoke was used in the tests, it wasn't to detect thermal air currents but to see if it was moving away from any thrust from the EM Chamber. Smoke is small .5 to 2 um and might be be directly effected. If not then look for other forms of accelerated energy, providing thrust emanating out of the EM Chamber.

I too would like to see a smoke test.  I can't see conservation of momentum being violated.  It just goes against everything we know both empirically and theoretically.  I think that even in the off chance that the EmDrive is not experimental error, conservation of momentum will still hold albeit in a more subtle manner than the classical analysis would expect.

You gave the illustrative example of a closed container with different traveling and standing waves of different frequencies and amplitudes bouncing around inside.  There is a very neat quantum mechanical reason that such a container is not truly closed.  Even in an infinite potential well, the wave function can extend outside the walls of the well, leading to effects such as tunneling.  Another great example of the wavefunction extending beyond barriers that appears to be somewhat related to the possible effect seen here is the Aharanov Bohm effect: http://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect.  This is due to the wavefunction of a particle outside of a container extending past the barrier of the container and interacting with the EM field on the inside of the container.

Now I leave this paper to ruminate upon:
http://arxiv.org/abs/0708.0681
Perhaps the EmDrive is acting as an evanescent mode photon rocket where momentum is carried away outside the cavity via this mechanism.

I can remember experiments (if not the references) of time delay measurements of sub-cutoff frequency waveguide transmission.  They were loudly poo-pooed at the time as claiming FTL information.

Offline SeeShells

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http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608

I believe the series of successful vacuum tests negates the need for a smoke stick test. Comments?

It's not only smoke, please I don't mean to upset you or anyone here, the smoke is more a analogy. The idea behind it is something is making it out of the EM device, unless you think the laws of CoE and CoM are being violated and I honestly don't. The question arises no matter how many equations I drudge through or papers I read. I want to say what tests this summer are you planning to do to try to see what form of energy/mass is causing the thrust? Maybe a sheet of carbon nano-fibers  would work  http://static-content.springer.com/lookinside/art%3A10.1186%2F1556-276X-8-60/000.png
 

The smoke test is still a good idea.  If the thrust proved to be due to experimental artifact, it could be due to multiple artifacts working in conjunction.  Wasn't the thrust quite a bit smaller in the vacuum tests?
« Last Edit: 05/10/2015 05:10 PM by lasoi »

Offline Mulletron

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Update on the replication attempt.

I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.

If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs. 

https://goo.gl/Q3jGN1

Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf

Great news, hopefully all those replication attempts by individuals or small teams will shed light on relevant parameters, and you are on the forefront. Can't you you go battery without DC/DC, what are the DC requirement of your RF amplifier ?

I need 6VDC 2A and 5VDC 2A. I guess this is a good time to explain my reasoning here. I am a firm believer that this EMdrive technology (if it is even viable) will never get off the ground if it isn't introduced and validated in a very public way.

One of my original goals was to encourage replication attempts by not only academia (which has resources) but also to make it accessible to your average Joe. In keeping with the second goal, I have decided to go with Plain Jane COTS wifi gear and see if I can make something work with that.

I'm well aware of how stupid that sounds.

I know that the frustum design that I currently have was originally driven by a high power (and dangerous to most people) magnetron. The frequency range of your average microwave oven magnetron and wifi are the same. I verified the frustum will resonate within this frequency range using a spectrum analyzer and a SNA. Mine works on wifi channel 1 and 10. Given that Eagleworks was able to observe thrust with only 2.6 watts for one of their tests*, I think this is an acceptable risk to take. Besides, it is just money right? So I am literally driving the frustum with the RF from the wifi camera (used to observe and is riding on the experiment) and a 2watt amp. I can scale this up to 20 watts using other amps if needed. Amps are cheap and plug and play.

* http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf

I think the frequency hopping aspect of the waveform might end up doing me in though.

So this is a gamble. I'm accepting the risk of not getting a successful replication attempt in hopes that if I do, I will have built a ready-made solution for mister tinkerer to easily observe anomalous thrust at home.

If all that fails, I'll just shove in a magnetron. I deal with voltages at work (big fry your eyeballs out radars) that literally will and do make your hair stand up on end as soon as you open the cabinet, so I'm comfortable with and respect high voltages.

Potential tinkerers should know, that that big capacitor next to the magnetron inside their microwave oven, WILL KILL THEM if they get in between it and ground. USE A SHORTING PROBE!

« Last Edit: 05/10/2015 05:21 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline deltaMass

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As I've mentioned, I am a strong proponent of a completely stand-alone system when it comes to measuring purported thrust from exotic devices (propellantless thrusters). The simple act of coupling to the stationary lab frame be it via coax, RF, Galinstan contacts or whichever, brings with it the possibility of artifacts masquerading as measured thrust. The whole thing has to be in a sealed box. And even then we are not out of the woods. Thermal power will tend to "balloon" the box volume and generate a buoyancy signal if the box is in air, aligned with local gravity's direction. Charges may accumulate on the box and generate phantom forces. Magnetic fields from outside, and/or from inside, may penetrate the box and also generate phantom forces. Only in space can all these phantoms be banished.

In space we need no balance; nor do we need any kind of force sensor. All we need is a measurement system to log the position of the DUT relative to its original null geodesic. This immediately kills two birds with one stone. We get a readout of initial "static" thrust from computing the initial acceleration, and, assuming actual off-geodesic motion subsequently ensues, we get the much sought-after free space dynamics.

Position measurement implies an interaction. Were LIDAR to be used, we have to correct our measured positions by taking into account the "photon sail" effect. It will be small, but it may yet be of a comparable magnitude to the actual thrust we detect. Then there's solar wind because we're not going outside the heliosphere (yet). And there is a direct photon flux from the sun. All these need to be addressed as sources of error.
« Last Edit: 05/10/2015 05:21 PM by deltaMass »

Offline Mulletron

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Update on the replication attempt.

I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.

If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs. 

https://goo.gl/Q3jGN1

Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf

Just a wild idea, but have you considered this form of powering :
http://en.wikipedia.org/wiki/Wireless_power

basically, contact-less induction would give you frictionless movement (except for the bearing friction and air resistance) and provide power. I'm however not sure what the electromagnetic implications would be on any surrounding devices...(fe, does it act as a magnetic brake?)

Secondly, not sure what would be needed to feed 1Kw of power. It might be not so practical all together...

Although.... I've seen street based induction plates for loading batteries of electric cars.

well.. it's just a wild idea flare... :)

I did consider wireless power but not enough wattage:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326813#msg1326813

See product at bottom link in above post.
Challenge your preconceptions, or they will challenge you. - Velik

Offline SeeShells

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I can remember experiments (if not the references) of time delay measurements of sub-cutoff frequency waveguide transmission.  They were loudly poo-pooed at the time as claiming FTL information.
:) In the 80s I remember being poo-pooed by a physics professor when I told him the the junction speeds in an IC or even transistor was the same as sound. Acoustic speed in the IC substrate. It's true, do the numbers for amorphous silicon or GAS. I like to keep an open mind and if something new presents itself in the violation of some of our ideas of how things work, I will jump on the bandwagon.

Offline dustinthewind

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Another paper that suggest we can get forces comparable to magnetic motors from (time/space phase em propulsion with near field effects further described here -->http://forum.nasaspaceflight.com/index.php?topic=36911.0).  Here is the paper below and a quote from page 9.

Exotic Matter and Propulsion within Maxwell’s Equations
Todd J. Desiato1
, Riccardo C. Storti2
November 6, 2003 v1"
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10.1027&rep=rep1&type=pdf

Quote: "Note that equation (4) is not the equation typically considered for EM propulsion, that is force = power c/ . This is a very week force because there is no Lorentz force coupled to the radiation emitter. For example, it’s like using a flashlight for EM propulsion.

The EGM Array produces EM propulsion that is derived from the exertion Lorentz forces on the 4-currents, not simply by the exhaust of EM radiation. This is the same principle that moves electric motors, in which the current carrying conductors are coupled to magnetic flux linkages. [16] Gradients in the flux exert Lorentz forces on the conductors to turn the motor. Reciprocity between the forces acting on each source is suppressed by engineering considerations such as proper phase control and by purposeful design.

For example, compare the thrust produced by a 1 watt flashlight to the torque produced by a 1 watt electric motor. The coupling of the 4-currents to the EM field to produce Lorentz forces does mechanical work that a radiated EM field alone cannot do.

The EGM Array is comparable to a linear electric motor and may be described as a linear Rotor with a holographic Stator. [10,16] Holographic referring to the time-varying superposition of EM fields surrounding the EGM Array, from which the Lorentz forces emerge."

This paper appears to be in agreement with the paper listed below.

DEF: The Physical Basis of Electromagnetic Propulsion
Mario J. Pinheiro
http://arxiv.org/abs/1502.06288

Quote: page 4 "As is exposed in textbooks (see, e.g., Ref. [3]), from Eqs. 8- 9 we can obtain the electric and magnetic elds, showing terms that vary as 1=r (radiation eld), 1=r2 (induction terms), and 1=r3 (electrostatic eld terms). Therefore, as it is shown in Ref. [15], the propulsive force can result from the near- eld and=or the far- eld (radiative) mode, that is, it is not always the radiative mode of propulsion that can be useful under the point of view of practical engineering."

One worry is that the propulsion would be that of a photon rocket.  However this should not be the case.  We have the potential to see much larger forces with the correct engineering.  It is my suspicion that this may be what is also occurring in the EM drive but due to the obscurity of what is actually happening inside it can't yet be confirmed.  Some suggestions [I might need to look up where I saw this in this thread] of the imaginary fields ([near field, exponentially decaying] associated with currents in the frustrum) being out of phase with the light at one end of the frustum make me think we might be dealing with this phenomena.

As stated in the top quoted article and others, there is the possibility of connections to this type of propulsion and manipulating space and time [zpf] [casimir energy density] ect with EM fields.   

How Electrodynamics with Statistical Mechanics
Can Imply Gravitation
Cynthia Kolb Whitney
Editor, Galilean Electrodynamics
http://worldnpa.org/abstracts/abstracts_7185.pdf

Archimedes’ Principle and Gravitational Levitation
Charles T. Ridgely
Fullerton, CA
http://ridgely.ws/inertia/Ridgely-Archimedes.pdf
« Last Edit: 05/10/2015 05:31 PM by dustinthewind »

Offline Mulletron

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Update on the replication attempt.

I have succeeded in making a safe stable balance (finally), but I am still absolutely bombing in my attempts to get power to the balance. The slip ring approach has its faults and I'm going to have to find some sort of flexible power pickup or abandon the whole slip ring idea altogether. If I stick with this approach, I'll never get anywhere near the sensitivity of Cavendish.

If I go to flying a battery and use DC-DC converters (http://www.amazon.com/dp/B00JUFJ1GA?psc=1) to power the electronics, any future of high power testing using this setup will be dashed. Not to mention I'll have to go to a much stronger torsion wire or a Dyneema braid (as opposed to the solid Dyneema line I'm using now) to hold everything up. As I know, engineering is a bunch of tradeoffs. 

https://goo.gl/Q3jGN1

Useful references I found:
http://www.alta-space.com/uploads/file/publications/feep/049-dAgostino.pdf
http://photonicassociates.com/ISBEP4-2.pdf

There must be some way of coupling the RF power to the cavity using feed horns or near-field antennas.    That would eliminate the need to weigh down the balance with a PA, batteries or achive a workable cummutator.    There may not be much gain at the frequency of interest but all you want to do is to transmit a fraction of the power.   Maybe 2 identical collinear dipoles would work.   The recieve dipole, mounted on the outside of the cavity, would connect to the internal loop used to drive the cavity.   If you have access to a network analyzer you could optimize the match and maximize the return loss.

The Rf source can just ride the balance, but the issue is providing electrical power to the gear. The feed horns you're speaking of are a thing though, they're called standard gain horns and also reference antennas *. I finally decided they were too expensive and a huge pain to use. Very low loss though.

* https://goo.gl/o2mwZH
http://www.nardamicrowave.com/east/index.php?m=Products&e=list&categoryId=195
http://www.pasternack.com/standard-gain-horn-antennas-category.aspx
« Last Edit: 05/10/2015 05:37 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline LasJayhawk



I need 6VDC 2A and 5VDC 2A. I guess this is a good time to explain my reasoning here. I am a firm believer that this EMdrive technology (if it is even viable) will never get off the ground if it isn't introduced and validated in a very public way.

One of my original goals was to encourage replication attempts by not only academia (which has resources) but also to make it accessible to your average Joe. In keeping with the second goal, I have decided to go with Plain Jane COTS wifi gear and see if I can make something work with that.

I'm well aware of how stupid that sounds.

I know that the frustum design that I currently have was originally driven by a high power (and dangerous to most people) magnetron. The frequency range of your average microwave oven magnetron and wifi are the same. I verified the frustum will resonate within this frequency range using a spectrum analyzer and a SNA. Mine works on wifi channel 1 and 10. Given that Eagleworks was able to observe thrust with only 2.6 watts for one of their tests*, I think this is an acceptable risk to take. Besides, it is just money right? So I am literally driving the frustum with the RF from the wifi camera (used to observe and is riding on the experiment) and a 2watt amp. I can scale this up to 20 watts using other amps if needed. Amps are cheap and plug and play.

* http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf

I think the frequency hopping aspect of the waveform might end up doing me in though.

So this is a gamble. I'm accepting the risk of not getting a successful replication attempt in hopes that if I do, I will have built a ready-made solution for mister tinkerer to easily observe anomalous thrust at home.

If all that fails, I'll just shove in a magnetron. I deal with voltages at work (big fry your eyeballs out radars) that literally will and do make your hair stand up on end as soon as you open the cabinet, so I'm comfortable with them too.

Some of the super fine strand the RC model guys use has a high ampacity, I think the 28 gauge is rated about 5 amps @20 degrees C rise. For the tests I would worry more about the voltage drop than the heating. Me I would feed it with 12 volts @ 2A and use linear regulators to reduce my wire count by 1.


Wifi signals? Who knows at this point, it might like the hopping.  :)

Offline deltaMass

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Continuing with the "Test In Space" theme.

We lack cheap space access for unmanned cargo. We have no railgun running from the coast of Ecuador up into the Andes to the east, and we have no Skylon/SABRE SSTO yet.  So we must pay many thousands of dollars per launched kilogram rather than what could be only tens of dollars.

What we do have is Cubesat and SpaceX. The problem is that the devices under consideration here won't fit even into the largest Cubesat. So let's talk miniaturisation.

What we have is photons in an asymmetric cavity. So let's use light instead of microwaves. I'll stop there for now.

Offline LasJayhawk


I can remember experiments (if not the references) of time delay measurements of sub-cutoff frequency waveguide transmission.  They were loudly poo-pooed at the time as claiming FTL information.
:) In the 80s I remember being poo-pooed by a physics professor when I told him the the junction speeds in an IC or even transistor was the same as sound. Acoustic speed in the IC substrate. It's true, do the numbers for amorphous silicon or GAS. I like to keep an open mind and if something new presents itself in the violation of some of our ideas of how things work, I will jump on the bandwagon.

I remember talking to an engineer at IFR in the mid 80's and telling him I wanted a blue LED. He told me the physics were to hard, and the only market would be a high beam indicator for cars. When I told him I wanted a blue LED so I could make a color video display he just laughed and said " That will NEVER happen. "  ::)

Offline deltaMass

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I would like advice on lifetime estimates of the power within the cavity - what is the expected half life? Does a simple expression exist involving the Q-factor? I remind that Q can be defined as the angular frequency multiplied by the ratio of (stored energy) / (rate of energy dissipation).

Offline Rodal

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As I've mentioned, I am a strong proponent of a completely stand-alone system when it comes to measuring purported thrust from exotic devices (propellantless thrusters). The simple act of coupling to the stationary lab frame be it via coax, RF, Galinstan contacts or whichever, brings with it the possibility of artifacts masquerading as measured thrust. The whole thing has to be in a sealed box. And even then we are not out of the woods. Thermal power will tend to "balloon" the box volume and generate a buoyancy signal if the box is in air, aligned with local gravity's direction. Charges may accumulate on the box and generate phantom forces. Magnetic fields from outside, and/or from inside, may penetrate the box and also generate phantom forces. Only in space can all these phantoms be banished.

In space we need no balance; nor do we need any kind of force sensor. All we need is a measurement system to log the position of the DUT relative to its original null geodesic. This immediately kills two birds with one stone. We get a readout of initial "static" thrust from computing the initial acceleration, and, assuming actual off-geodesic motion subsequently ensues, we get the much sought-after free space dynamics.

Position measurement implies an interaction. Were LIDAR to be used, we have to correct our measured positions by taking into account the "photon sail" effect. It will be small, but it may yet be of a comparable magnitude to the actual thrust we detect. Then there's solar wind because we're not going outside the heliosphere (yet). And there is a direct photon flux from the sun. All these need to be addressed as sources of error.

Thank you for taking the time to write the reasons to fly the EM Drive in space.

Now, can we go in further detail with this?

The question is at what minimum altitude would this make sense. 

In LEO there are drag and magnetic field effects, so in LEO the EM Drive would not be really under the action of no forces.

What kind of orbit do you think it would be necessary to achieve to properly test an EM Drive in orbit, given that the only measurements we have for the EM Drive in a vacuum are the recently (2015) experimental measurements from NASA Eagleworks?

« Last Edit: 05/10/2015 05:51 PM by Rodal »

Offline Mulletron

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The smoke test is still a good idea.  If the thrust proved to be due to experimental artifact, it could be due to multiple artifacts working in conjunction.  Wasn't the thrust quite a bit smaller in the vacuum tests?

Quote
Wasn't the thrust quite a bit smaller in the vacuum tests?
It sure was, you can't deny that:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608

I note that Paul March admitted his frustum is vented to allow air to escape:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1327937#msg1327937

My comments on that:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1330846#msg1330846
-see re-pressurize the cavity.....based off of 1)


« Last Edit: 05/10/2015 05:57 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

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