Can Scientists Make a Tank Invisible

[bobbymike]

From Defensetechblog -

Unauthorized Access

 

[Simon666]

From Defensetechblog - http://www.defensetech.org/archives/004987.html#comments

As has been pointed out in the comment section, the answer is no. Cloaking only works in what is called "the near field", so only objects smaller than (at most a few multiples of) the wavelength of the radiation involved can be cloaked. For light, that would mean at most a few microns. Passive cloaking is further limited to one wavelength and some harmonics, active cloaking can do somewhat better but is still just theory.

 

[PNorwood]

Here is a .pdf file which explains how it is done.
(The file is from the link which was posted by bobbymike)

http://www.opticsinfobase.org/DirectPDFAccess/CF124420-BDB9-137E-C46C9C4B3B4F444A_184385.pdf

 

[Grey Havoc]

On a related note: http://gcaptain.com/invisibility-cloak-ships/?29425

While the cloak postulated by Urzhumov differs from other cloaks designed to make objects seem invisible to light and sound, it follows the same basic principles – the use of a man-made material that can alter the normal forces of nature in new ways.

In Urzhumov’s fluid flow cloak, he envisions the hull of a vessel covered with porous materials – analogous to a rigid sponge-like material – which would be riddled with holes and passages. Strategically placed within this material would be tiny pumps, which would have the ability to push the flowing water along at various forces.

May have some interesting naval applications apart from the obvious.

 

[Dragon029]

Here is a .pdf file which explains how it is done.
(The file is from the link which was posted by bobbymike)

http://www.opticsinfobase.org/DirectPDFAccess/CF124420-BDB9-137E-C46C9C4B3B4F444A_184385.pdf

I believe the idea behind using metamaterials to cloak large objects is to pass light around one microscopic structure, to another next to it and then continuing the process until it reaches the front of the vehicle, where it encounters another type of structure that diverts the light forward, like a daisy chain of bizarre physics.

Personally, the thing I always wonder about is that if they get the materials on and working, etc - how exactly will they protect them, seeing as such minute structures are quite susceptible to damage. If they're coated with some clear plastic, etc that will be visible. Additionally, I'm not sure what effects that would have on thermal visibility, as heat will obviously be conducted from the vehicle. That would be where things like that wolf-something IR stealth tech would be handy.

 

[Gerard]

I don't have any problem with the idea that technology will be able to make a tank invisible.

That is, to human, tv FLR, thermal viewers. Radar too. When on a nice concrete parade ground.

I've got doubt abouts how it will manage in the Arctic, dessert, tropics, mud, dust, rain, crossing a river. Or when a few 152mm shells airburst 10 or 20 yards away.

Also, how do they get rid of the thermal exhaust, which might be seen by a satellite / UAV ? Heat sinks can only do so much ? And what about when the main gun fires ? though railguns may help there.


Regards,
Gerard

 

[Lauge]

....though railguns may help there.

Not necessarily. Railguns, not being 100% effective, will produce copious amounts of waste heat that you need to get rid of somehow (further stressing those heatsinks you mentioned).

Also, for any railgun worth its salt, the projectile is likely to be followed out of the muzzle by a burst of plasma from the conductive sabot and the armature.

Regards & all,

Thomas L. Nielsen
Luxembourg

 

[Dragon029]

I don't have any problem with the idea that technology will be able to make a tank invisible.

That is, to human, tv FLR, thermal viewers. Radar too. When on a nice concrete parade ground.

I've got doubt abouts how it will manage in the Arctic, dessert, tropics, mud, dust, rain, crossing a river. Or when a few 152mm shells airburst 10 or 20 yards away.

Also, how do they get rid of the thermal exhaust, which might be seen by a satellite / UAV ? Heat sinks can only do so much ? And what about when the main gun fires ? though railguns may help there.


Regards,
Gerard

Theoretically and assuming it works exactly as hoped (taking the light from behind it and bending it around the surface of the object, to in front of it), you should only see a shadow on the ground and possibly a few floating lenses. There wouldn't be any flickering, very little difference in contrast, brightness, etc, simply because it's not a digital or electronic system, simply a material that places a visual portal on the silhouette of an object, linking to another located 180 degrees around the object.

Of course, that is the ideal situation. How it's implemented will dictate how well it works. For example; they can't make materials that cover every possible convergence angle, so there won't be that many dissimilar angles on a tank. This would obviously be problematic, but it can be solved by placing a shell over the tank, covered in the material. However, that in turn alters the maneuverability of the tank as you would have a big turtle shell covering it. You could have it mechanically move to raise and tilt it over terrain (guided by radar or laser sensors), but that's adding more mechanical complication. Additionally, applying the molecular structures will likely be a very slow process unless some amazing assembly tool is developed.

 

[Grey Havoc]

For infantry optical signature reduction, this might have some application.

"We are currently investigating another, milder candidate reagent which would allow us to study live tissue in the same way, at somewhat lower levels of transparency" he said. "This would open the door to experiments that have simply never been possible before."

 

[Grey Havoc]

Apparently Hägglunds has revealed a CV90 equipped with a prototype of what could be described as an integrated thermal cloaking system. Complimentary systems for visual and radar cloaking are currently further back in development. (H/T to Micael over at HP&CA)

Bing translation:
http://www.microsofttranslator.com/BV.aspx?ref=IE8Activity&a=http%3A%2F%2Fwww.nyteknik.se%2Fnyheter%2Ffordon_motor%2Fbilar%2Farticle3246446.ece

Original Ny Teknik article:
http://www.nyteknik.se/nyheter/fordon_motor/bilar/article3246446.ece

 

[robunos]

Apparently Hägglunds has revealed a CV90 equipped with a prototype of what could be described as an integrated thermal cloaking system. Complimentary systems for visual and radar cloaking are currently further back in development. (H/T to Micael over at HP&CA)

Bing translation:
http://www.microsofttranslator.com/BV.aspx?ref=IE8Activity&a=http%3A%2F%2Fwww.nyteknik.se%2Fnyheter%2Ffordon_motor%2Fbilar%2Farticle3246446.ece

Original Ny Teknik article:
http://www.nyteknik.se/nyheter/fordon_motor/bilar/article3246446.ece

English version from Sky News...
http://news.sky.com/home/technology/article/16063257




cheers,
Robin.

 

[CostasTT]

Another photo:

 

[pathology_doc]

I suppose thermal cloaking could make the statistical difference between being hit by some sort of autonomous submunition or missed, or might mask your presence for long enough to get in a bit closer and be sure of killing what's looking for you, and that might be worthwhile; but having what the Klingons and Romulans have seems about as far off as the actual USS Enterprise and James T. Kirk IMO.

 

[Grey Havoc]

Via MilitaryPhotos.net and DISCOVER magazine, here's the short BAE Systems video (which, of course, doesn't mention Hägglunds or the Swedish government's involvement):

http://www.youtube.com/watch?v=ZbxcVQsE_3g&feature=player_embedded

 

[Yellow Palace]

Via MilitaryPhotos.net and DISCOVER magazine, here's the short BAE Systems video (which, of course, doesn't mention Hägglunds)

You mean BAE Systems Hägglunds AB?

 

[sublight]

DARPA hasn't done something similar in the past?

 

[Grey Havoc]

Via MilitaryPhotos.net and DISCOVER magazine, here's the short BAE Systems video (which, of course, doesn't mention Hägglunds)

You mean BAE Systems Hägglunds AB?

BAE Systems appear to be currently trying to get rid of the Hägglunds identity, some reports are suggesting they're stripping Hägglunds for anything they consider useful, and closing the rest.

 

[JFC Fuller]

BAE is consolidating its Swedish operations after they lost both the Swedish wheeled vehicle requirement and the UK FRES-SV requirement. In short the Swedish operation did not have enough work to stay the size it was.

 

[Grey Havoc]

Legal storms may be ahead: The Cheshire Tank

 

[Grey Havoc]

'Organic camouflage': http://www.militaryphotos.net/forums/showthread.php?204414-A-libyan-tank-with-sheep-s-skin-camouflage ;D

 

[Grey Havoc]

Military wise, this will probably be more relevant to naval applications in the short term: Physicists Create Magnetic Invisibility Cloak (ScienceNOW via Wired.com)

But that doesn’t make a superconducting can a magnetic cloak. That’s because outside the can, the field produced by the superconductor will alter the applied field and reveal its presence. In a nutshell, the field can be thought of as a distribution of lines of force that vaguely resembles a weather map of winds. The superconducting shield pushes the magnetic field lines outward, creating a hole in the field. So the trick to making a cloak for static magnetic fields is to counteract that distortion. In 2007, Pendry and Ben Wood, also of Imperial College London, proposed that such a cloak could be made of a material that repels magnetic fields in one direction and attracts them in the opposite direction. Unfortunately, this self-contradicting material doesn’t exist.

But Alvaro Sanchez of the Autonomous University of Barcelona in Spain and colleagues propose a way to approximate the impossible stuff by wrapping the cylindrical shell of superconductor in layers of materials that do one job at a time. Some layers are easily magnetized and will essentially pull the external magnetic field lines around the cylinder; those layers alternate with shells of superconducting plates that push on the field, preventing it from coming straight in toward the center. The attracting layer would be made of tiny magnetic particles, like submicroscopic iron filings, mixed into a nonmagnetic material such as plastic.

The cloak could handle fields of any shape and any strength within what the superconductor can stand. If the external field gets too strong, the magnetically induced current becomes so powerful that it knocks the superconductor out of its resistance-free state and ruins its field-repelling qualities. Computer simulations showed that the cloak could work with as little as four layers, but with 10, it would guide a magnetic field nearly as well as a perfect cloak, as Sanchez and colleagues report today in the New Journal of Physics. “It doesn’t need to be a closed cylinder; it can be an open cylinder or open plate, although in this case the magnetic cloaking properties are reduced,” Sanchez says.

The hypothetical device would work as a magnetic cloak by creating a space that is protected from an external magnetic field while at the same time causing no telltale distortion of the field. Alternatively, it could also be used to conceal a magnetic object and prevent its magnetic field from extending out into space—a pie-in-the-sky dream for shoplifters trying to steal clothes pinned with magnetic security tags.

[IMAGE CREDIT: Wired.com]​

 

[mithril]

certainly seems easily applicable to submarines. subs are already tubular, and being nigh invisible to MAD systems would take out one of the less noticable anti-sub detection options.
if you can layer the subs hull with anti-aucoustic metamaterials as well, you could reduce it's vulnerability to sonar too..

Military wise, this will probably be more relevant to naval applications in the short term: Physicists Create Magnetic Invisibility Cloak (ScienceNOW via Wired.com)

But that doesn’t make a superconducting can a magnetic cloak. That’s because outside the can, the field produced by the superconductor will alter the applied field and reveal its presence. In a nutshell, the field can be thought of as a distribution of lines of force that vaguely resembles a weather map of winds. The superconducting shield pushes the magnetic field lines outward, creating a hole in the field. So the trick to making a cloak for static magnetic fields is to counteract that distortion. In 2007, Pendry and Ben Wood, also of Imperial College London, proposed that such a cloak could be made of a material that repels magnetic fields in one direction and attracts them in the opposite direction. Unfortunately, this self-contradicting material doesn’t exist.

But Alvaro Sanchez of the Autonomous University of Barcelona in Spain and colleagues propose a way to approximate the impossible stuff by wrapping the cylindrical shell of superconductor in layers of materials that do one job at a time. Some layers are easily magnetized and will essentially pull the external magnetic field lines around the cylinder; those layers alternate with shells of superconducting plates that push on the field, preventing it from coming straight in toward the center. The attracting layer would be made of tiny magnetic particles, like submicroscopic iron filings, mixed into a nonmagnetic material such as plastic.

The cloak could handle fields of any shape and any strength within what the superconductor can stand. If the external field gets too strong, the magnetically induced current becomes so powerful that it knocks the superconductor out of its resistance-free state and ruins its field-repelling qualities. Computer simulations showed that the cloak could work with as little as four layers, but with 10, it would guide a magnetic field nearly as well as a perfect cloak, as Sanchez and colleagues report today in the New Journal of Physics. “It doesn’t need to be a closed cylinder; it can be an open cylinder or open plate, although in this case the magnetic cloaking properties are reduced,” Sanchez says.

The hypothetical device would work as a magnetic cloak by creating a space that is protected from an external magnetic field while at the same time causing no telltale distortion of the field. Alternatively, it could also be used to conceal a magnetic object and prevent its magnetic field from extending out into space—a pie-in-the-sky dream for shoplifters trying to steal clothes pinned with magnetic security tags.

[IMAGE CREDIT: Wired.com]​

 

[bobbymike]

VANCOUVER -- A Maple Ridge, B.C., inventor claims to have discovered what scientists, armies, children and science fiction fanatics have dreamed of for generations -- a fabric material that can make a person or object completely invisible.
“We were able to make a six-inch object disappear,” Guy Cramer said of his accidental discovery. “I went back to the shop and up-scaled the material and it worked just as well on a person.”
Cramer is the founder of HyperStealth Biotechnology, a company that designs digital camouflage patterns for clients including the Jordanian and Afghanistan armies. He said the Canadian and U.S. militaries are now discussing arrangements to potentially adopt his light-bending technology, which could potentially be used to hide entire airplanes and buildings.
“It can actually work in 360 degrees, so someone behind me can see what’s on the opposite side, and someone in front of me can see what’s behind me,” Cramer said of his fabric, which would put his discovery far ahead of currently known research.
“We’ve made an entire vehicle disappear.”
However, Cramer is not revealing any evidence of his invisible material — even the images posted on his website are photo illustrations.
“We can’t show it because someone will pick apart from those photos how it actually works,” he said.

 

[Grey Havoc]

http://www.telegraph.co.uk/technology/news/9902307/Invisibility-cloak-unveiled-at-TED-conference.html

The invisibility cloak has long been a staple of science fiction, with Harry Potter famously using one in his wizard adventures.

But to gasps from the audience, a scientist from Nanyang Technological University in Singapore demonstrated an experiment that appears to make it more than the stuff of fantasy.

A small box made of calcite optical crystal was used to bend light around an object, making anything placed behind the box appear invisible to people watching the demonstration at the TED conference.

Professor Baile Zhang said he was inspired to create the invisibility device “just for fun”.

“I just think the idea is cool,” he said. “Plus, I hope this work will demonstrate that simple tools can sometimes fulfil important functions that previously required complicated methods.”

Professor Zhang admitted that his research was in its early stages, and said that his team was still working out how to make larger and more useful prototypes of the invisibility cloak, according to The Times.

 

[Grey Havoc]

View: https://www.youtube.com/watch?v=1k1X2nBC9Q8


CV90120 Ghost

 

[shin_getter]

I wonder why stealth land vehicle doesn't seem all that popular. Is there a few sensors that can not be effectively neutralized at cost and thus rending the whole concept marginal?

 

[GARGEAN]

Unlike in the air, main ground search and targeting sensors are thermals and visual band. And those are much harder to work with, not talking about working against ground is much harder than working against sky.

 

[Justo Miranda]

In the mid 90s, the advanced achieved in Computer Generated Holography, wavelength computation with Fourier transform method and Point Source Holograms, allowed the creation of holographic images in 3D around an object to hide it. But the system just worked with static objects and the Phased Array Optics required a considerable amount of electronic equipment.

In 2003, researchers at the University of Tokyo developed an active camouflage system with video cameras that registered the background to project it against the object that should be camouflaged.

In 2004, the discovery of the graphene made possible the manufacturing of curve video screens and adapts them to any surface. An vehicle with a coat of grapheme screens and equipped with video cameras that register the background from any angle and project it on the screens at the other side, may become practically invisible.

The layers of graphene are super-thin and several of them, with different properties, may be superimposed. Under the optical screen, it is possible to locate a layer formed by hexagonal elements of grapheme that may be heated or cooled down in a selective way, thanks to the Adaptiv system, developed by BAE systems in 2011. This layer would very efficiently act as infra-red camouflage.

 

[Grey Havoc]

Here's the video I posted back in September 2011 with an updated link:

View: https://www.youtube.com/watch?v=ZbxcVQsE_3g

 

[steelpillow]

Point a camera out the window, by propping it up on the window sill with a book. Place the monitor in line behind the camera and book, and stand so the screen image lines up with the view. Voila, your CCTV is now cloaking the book! This is your own working example of "active cloaking" technology. Practical on the battlefield, it is not.

A big problem it shares with the kind of near-field EM manipulation described in the article is that it tends to be highly directional. One step sideways and you can see the darn thing plain as day, if perhaps a bit distorted. An omnidirectional cloak, even one with a useful aperture, is still way beyond possibility.
What about a cylindrical display? Ah, that can only work with 3D viewing technology, otherwise the image must rotate sideways and constantly distort as as the viewer moves around the screen. For example a background object on the left must show on the left slope of the screen, and be stretched out across the curve. Suppose you step to the right for a better look, then its image must follow you round even further, to the centre of the screen relative to you. Again, the display must be tailored exactly to the viewer's position.

Another problem is bandwidth. The device has to be tuned precisely. Cloaking from say a frequency-hopping or spread-spectrum pulse-based digital radar is again out of reach.

Holography can help, but here the problem is resolution; like colour holograms the cloaking effect is crude and badly blurred.

Note too that the article's analogy with stealthy planes and subs is false. Today's radar and acoustic stealth are both about reducing the target to a black silhouette, eliminating emissions. Equivalent to giving your book a black dust cover. Cloaking is totally different, in that it is all about the emissions.