Recent Posts

Pages: [1] 2 3 ... 10 Next
1
I was just wondering - if Squeezed Light can be possible, can Stretched Light also be possible? Or is that what they call Amplitude Squeezed Light?

Regardless of how it's accomplished, we can all see what the converse situation would look like - a lower signal-to-noise ratio that raises the background noise. Shall we call it excitation of the Vacuum Fluctuations?
Consider that if those background fluctuations are what you're trying to push off of, then your Action-Reaction could benefit from a more vigorously fluctuating (hotter?) Vacuum.

In my model, that would be "warp drive", or K < 1, c/K > c.

I look at it this way. The QED Zero Point Field, (ZPF) is the lowest allowed energy state for an oscillator in a potential. So the oscillators that make up matter (atoms) do not naturally drop below this minimum energy state.  The atoms are driven by the ZPF of the vacuum to be in equilibrium with it. The presence and interaction with external matter causes damping, or a loss of power from the oscillator-vacuum system. The particle falls, looking for equilibrium in an asymmetrical environment.  In other words, the symmetry is broken. Gravity has a symmetry, just as other forces in the SM have a symmetry. They exist only when the symmetry is broken.


The frustrum is an (asymmetric) resonant cavity with photons supposedly bouncing back and forth - but couldn't this "resonant" bouncing really amount to a delocalization?
Isn't that exactly how they refer to electron-delocalization in SP2 aromatic carbon -- "resonance" states?


If QED cavity resonance really does amount to delocalization, then perhaps its more diffuse nature could lead to greater coupling - analogous to the way the more diffuse corona-discharge can have greater coupling with a fuel-air mixture as compared to the sharper arc-discharge. So, to me, that sounds like the possible means of augmenting Action-Reaction by a Photon Rocket.

But the idea of "stretched light" (Amplitude-Squeezed Light?) and a correspondingly "smeared out" photon seems to also be a way of making light more diffuse at the individual photon level, which perhaps could also achieve better coupling with the Vacuum.

So which way is better? Should they both be tried together, for possible enhanced results?

Then there is the idea of Gamma-Gamma photon coupling at higher energies (shorter wavelengths) - so when your energy is high enough, you're no longer as bosonic and you're more interactive.

Could there be possible interplay between:
1) the choice of frustrum dimensions and material
2) the choice of light frequency to pump the cavity with
3) the level of LightSqueezing applied to the photons
2
SpaceX Mars / Re: Red Dragon Discussion Thread (2)
« Last post by JamesH65 on Today at 06:29 PM »
Why do you think DV2 will have more dV capability?

They made the space available by extending that bottom cylinder. They may have done that with RedDragon in mind. Tanks in the pressurized volume is just not a good idea and they need more propellant to get near the 2-3 t payload Elon Musk mentioned. It would also help a lot if they ever service a space station in the vincinity of the moon.

Will RD be pressurised? Doesn't seem any point to being pressurised to me.
3
Advanced Concepts / Re: Why the lack of SSTO projects?
« Last post by IsaacKuo on Today at 06:23 PM »
Better to use nitrogen in that case instead of oxygen. There's like 4x as much nitrogen, and it's nearly inert.

That's true, assuming you can use liquid nitrogen in one (or both) of the propellant tanks.
4
SpaceX Mars / Re: Envisioning Amazing Martian Habitats
« Last post by RocketmanUS on Today at 06:16 PM »
Not sure if this is any clearer...

Top down view.

Green walls are unpressurised. Heavy black walls are pressurise-containing main walls. Blue segments are pressurisable airlock and bulkhead doors. Vehicles are black/yellow. Spacesuits are black/white.
Very nice start, I like having the unpressurized bay. Keeps dust out of airlocks and shields from wind. If there is to much dust in the air outside they could still see.
5
It is tempting but in reality there is no need for QV, Dark Energy or exotic effects to explain the thrust. Following Desiato-Rodal's classical theory combined with basic optomechanics, it should work following the conversation so far. 

I have been thinking about the design and have developed another concept which is attached. Let me know what you think.

Referenced urls:
http://physicsworld.com/cws/article/news/2016/feb/26/surreal-behaviour-spotted-in-photon-experiment
www.sciencedirect.com/science/article/pii/S0008622313010695
http://www.radioeng.cz/fulltexts/2015/15_03_0661_0669.pdf
www.physics.hmc.edu/~saeta/courses/p111/uploads/Y2011/HSChapter4.pdf
http://xlab.me.berkeley.edu/pdf/027.pdf
http://forum.nasaspaceflight.com/index.php?topic=40959.2843


P.S. Amazing work has been done. This thread has been an historic turning point. In case people haven't realized, higher order and secondary effects were basically proven to be present due to the chaotic pattern in the long cone sims!!! Again, this is a huge leap forward since it essentially invalidates Egan's analysis. Egan did not consider secondary effects which happen because the EM drive is not a closed or steady-state system. FEKO and Egan both shared equations, just the conclusions which can be drawn from each appear to be vastly different. Clearly there is a knowledge gap which exists at the cut off in an asymmetric cavity which Dr. Rodal has valiantly tried to fill before. Phd students take note. I would recommend more work on increasing Q and changing the design to increase the potential between the upper and lower cavity. Also, I am very concerned that the theory is incorrect for one simple practical reason: it predicts thrust for symmetric cavities with asymmetric internal fields. Meberbs made some great points earlier along these lines. Surely somebody would have noticed this by now after 100+ years of experimentation? 

Best Regards,
LA

To me it seems that the "chaotic pattern" of the illustration of the average Poynting-Vector is an artefact because of the finite mesh density and the autoscaled values.


6
By request, here is a speculative simulation of the Mini ITS. I've assumed the Mini BFR will have 7 x Raptor 50, and the Mini BFS 2 x Raptor 80. The Mini BFR should have no trouble landing on a single Raptor 50, but the Raptor 80s on the Mini BFS might not be able to throttle deeply enough to land. Perhaps four of the methalox vernier thrusters seen on the full scale BFS could be used as landing engines? If they have 10mT thrust each, they should be able to land the 18mT Mini BFS + fuel.

The sim gets about 118mT to a 300 x 300 km orbit. Depending on how much ullage you think is necessary, I suspect 70-80 mT of that could be payload, and still have enough fuel to land the ship.


Why not 9 engines on the BFR as F9 has?
What percentage of propellant is left for return and landing for BFR?
What is the dry mass of the BFS?
7
This propulsion method would be low Isp, which means even with electric, it'd be decently high thrust. Easily high enough to get you off of the moons. And if you thrust at perigee, you still get Oberth effect just fine.

If I get 1Newton of thrust at 5000s Isp, the at 50s Isp and the same power, you get 100x that, or 100N of thrust. Comparable to chemical thrusters, and plenty good enough for the concept outlined here.

That requires on the order of 10 kilowatts, implying something like 100 square meters of solar panels. Heavy and big, and they need to be folded up during aeroscooping.

No, electric propulsion trying to operate for minutes isn't going to compete with a refinery operating over days.
8
The quote attached is a copy of my post in the EMDrive main thread #9.

The simulations are related to the discussion of the {Q}uality -factor when the small end of a truncated conical cayity resonator is below, at or above the cutoff diameter of a cylindrically waveguide.
To use the related value is frequently stated by TheTraveller(TT) (he says he quotes Shawyer in this regard) and have suggested to take it as a rule, i.e. to make the small diameter equal to the cutoff diameter.
Several explanations where given by TT but nothing conclusive.
For example, that there is no reflection at all if the small end plate diameter is below this cutoff rule. This was debunked as nonsense by Dr.Rodal and others.
As one of lastest "explanations" TT stated that the Q for such a cavity is much smaller  ( or even: "...below anything usefull..") than for a cavity that fits the so called cutoff rule.
The results shown here debunk this to be nonsense also.

Please note that this tells nothing about differences related to (possible) thrust generation.

As you can see in the first two results the situation differs from calculation to calculate. The reason is slightly different mesh size and coupling factors.

Don't forget to include the spherical end-plate frustum with Q of 111,454. That is a pretty significant increase.
Again, at the moment I don't believe in this Q values based on calculations with HOBF. I get freaky inconclusive results when using it.

EDIT
This is the same frustum as used for the Q compare but using HOBF and fine mesh. Instead of natural possible QL~36000, i get 207000 loaded Q! ???
Can EmPro calculate Q?
If yes can you check the results with EmPro?
https://forum.nasaspaceflight.com/index.php?topic=41732.msg1626572#msg1626572

FEKO SE calculation is above, EMPro (FEM Eigenresonance solver) below.
Dimensions are the same, material is copper in both cases. EMPro results should show Q0.

Can you lower the frequency of the one on the right to 2.45 GHz, by expanding the Big diameter? I need to know what those dimensions would be. 2.6 GHz is too far outside the amplifier's range.
Todd I am not sure this is what you like to see. However, the field pattern looks very interesting.
Q0=74382

Can you simply scale the frustum on the right, of "your" original image, until the frequency is 2.45GHz please? Just to compare to my wide base idea. It's hard to choose which one I want to spend money on.

Thanks.
I have parameterized all dimensions now, therefore I can scale the whole thing by changing one number only*. After increasing the frustum step by step, it matched 2.45GHz almost exactly.

*This means all dimensions(!) including the antenna radius, antenna wire radius and its position, as well as the frustum size. All of this depend on this simple scaling factor.

Regards
The geometrie should be fine to go with, other modes are ~50MHz away.
9
New Physics for Space Technology / Re: Monomolecular trap
« Last post by meberbs on Today at 05:52 PM »
That is basically what you described,but you still haven't worked out any thermodynamics, or compared efficiency to that of standard thermodynamic cycles.
10
In-Space Hardware Section / Re: NASA Restore-L LEO servicing
« Last post by TrevorMonty on Today at 05:46 PM »
Repair of satellites by crews at DSH could be reality. It would require likes of OA tug to haul them from GEO to DSH. Probably not financially viable for comsats but $B government satellite is different story.
Pages: [1] 2 3 ... 10 Next