China fires lasers at US satelites

I went to some chinese forums, and some people there had the allowing response:

"The Amercian government is once again making up 'scary stories' to frighten its people, so that the government can increase their military spending without being further questioned."

[edit on 9/28/2006 by warset]

posted by: thelibra
A Lesson in Physics and HEWs

I can actually speak with a tad bit of authority on this subject, as I attended an IEEE conference where one of the tracks was a whole lecture on the use of HEW weapons, and I can say with 99% certainty that High Energy Weapons of any sort, including "laser beams" are impractical across that distance. Here's why:


HEWs heat, not cut or bore. - Lasers, as weapons, are not intended to cut through objects, bore through them, or anything of the sort. Their purpose is to heat up the target to the point where its operation thermal threshold is exceeded and the device is thusly disabled.


Cannot track well through atmospheric particles - Despite how clear or stable the air appears to be, it is, in fact, exponentially detrimental to tracking with a laser. As we are all well aware, a laser is composed of highly concentrated photons. Over short distances, the sheer volume of photons are able to mostly burn through the dust and vapor floating in the air. However, it is important to note that some photons are deflected when this happens, their trajectory might change as subly as a fraction of a degree, or as much as 180 degrees, depending on the angle of incidence (the angle the photon strikes relative to the surface of the particle it hits) and the ablation (reflectiveness) of the particle. The important thing to remember is that particles floating in the air are MUCH more massive than photons.

The effect would be akin to throwing a rock at the side of a building. Now, if you had billions of little rocks, equal to the volume of, say, a stadium, and were able to forcefully project them at a building the size of a house, you would still end up destroying the house and sending a LOT of rocks out the other side, in roughly the same direction, but a portion of the rocks would be lost during impact, or deflected, leaving fewer rocks most likely travelling at a different angle.

This is one of the reasons when you shine a beam of light (like a flashlight), the light spreads out further and weaker the longer the distance. A laser is little more than a very very powerful concentrated flashlight, and is thus susceptible to the same trajectory-altering physics.

The end result is that prolongued laser exposure to surface will "dance" at the impact point in a random fashion. The more atmosphere it is beamed through, the larger the dance will be on the target. As of about two years ago, the best they managed was a two-foot radius dance at a littler under 40,000 feet with two stationary targets, over the course of 30 seconds. It was not a solid dot that slid around the radius, but rather a jumping dot that sometimes disappeared altogether. For a satellite to remain in orbit, the distance to Earth's surface must be at least 35,768 km, most are around 45,000 km.

That means over 117,349,081 feet of atmosphere must be passed through. Using only simple math, that equates to a "dance" of 5867 foot radius. Since the effect is actually exponential, it is unlikely to be that small in reality.

With only a two-foot dance, there is still not enough continuous contact to generate enough heat to disable craft at only 40k feet, within Earth's comparatively thick atmosphere and hotter temperature, much less the much colder depths of space where there is no air insulation to trap heat.

So effectively to disable a satellite with a HEW, you would have to overcome the random particulates and airflow through the atmosphere, and to do that, you've either got to be in space, or somehow create a vacuum between your laser and the target for the length of the heating.

I think this is related to the argumentation i have provided!

Thanks for posting that information Tetra, It was very informative!!
So the general consensus here is that this is not a very effective weapon, but if we have had the technology to fire a laser at a 3 foot square on the moon since the 70s, then surely hitting something the size of a small truck in orbit with a far more powerful laser would be a lot easier, given you had the equipment to track it. If your not trying to destroy the satellite but blind it does it need to be that accurate, maybe a beam a few inches wide rather than a few millimeters after distortion and degradation.
Warset, the US is trying to hide the fact that China is either testing or using this weapon against US spy satellites, If thats true I cant see how they can be making up stories to frighten its people, when they are trying to keep this quiet and are trying to pressure China in to helping them solve its problems with Iran and North Korea.

[edit on 28-9-2006 by Kurokage]

i would still claim that the mirror transmits radio waves and they use that to pin point its exact location.

also i would theorise that small is an advantage in these situations, since it would be less likely to "dance" to put it in libras terms, the more powerfull the more sporadic spreading of the photons, unless backed up by a power source we havent heard of yet, or at least its own atomic powerplant. Which arent at all impossible!

I heard that the lazers aren't very good at destroying things because once they start to vaporize the surface of the target the vapor/debris cloud caused immediatly around laser contact site actually partially deflects the laser and absorbs even more of the lasers energy which has to re burn a path through said cloud.

I wouldn't be suprised if 100 years from now a slug thrower will still be the prefered weapon over a laser/beam type weapon. A half ounce piece of metal slamming into anything at 1140 feet a second will still be the more economical way to transfer destructive energy to a target. Imperial Stormtroopers would get smoked probably quite quickly by a squad of guys with assult rifles.

But could the laser just be enough to blind the satalite for a few minutes. I think thats possible. Tetra seems like the expert tell me what you think.

Lasers...Sorry Crappy spelling.

in a 100 years i would think we had a rail gun like weapon, where we electrically charge a perfect metal ball, and fire it at the desired target at around 10 times march.
So yes i believe the same as you! Blunt objects just hit harder, where lasers becomes effecient is in space where they arent obstructed by molecules.

But it would never be a laser beam, since a laser beam would disapear the instant it lost contact with its power source, but over large distances laser is preferable because of sheer speed.

Tetra,

I agree about the distance and speed lasers have in space, but do they really transfer energy efficiently enough to be used as destructive weapons? What about the above problem i've heard they have run into with the laser and the vaporized cloud thingy? Have you heard of a similar phonomena?

But couldn't the lasers still be intense enough to temporarily blind the sensors on the satallites?

Well to traverse space you would need a large power source anyways, and the weapon in theory could be in orbit using only a minimal bit of its total power, maintaining orbit while using the rest on "fuelling" the laser.
In space, there would be nothing to hit besides its attended target, no oxygen molecules to vaporize, just a stray object occasionally.

The problem as I see it isn’t the power supply, we could easily muster the power needed to fire a laser from earth and some 40000 kilometres out in space, the problem is hitting the satellite at an exact point blinding its optical capabilities.

It is not just hitting a truck sized object; I would speculate that you would have to hit the lens in order to blind it!
That is something the size of a toaster oven, moving 40000 kilometres away with the speed of around 2000 kilometres per hour.
So in accordance with what thelibra stated, we are hitting this toaster sized lens moving at above mentioned speed and distance with an error margin of several feet.

As I said earlier, I would also believe that this SPY satellite does not reflect radio waves and it should be in passive listening mode only.

The more I think about this the more difficult it seems, in my opinion.


EDIT : Typo


[edit on 28-9-2006 by Tetragrammaton]

Yeah it seems unlikely that the laser would be accurate enough. Sounds really difficult to do actually. Could be US fear mongering again. If China does have targeting systems that accurate then we have really been asleep at the wheel.

Interesting...though the first successful test of a ground based Mid-Infrared Advanced Chemical laser partially disabling an orbiting satellite was done almost ten years ago in 1997 by the United States.

How far do you think the technology has come since then?

Articles Below:

www.armscontrol.org...

DoD News Briefing:

www.fas.org...

Whaa!!! good find. Reading over the stuff now. Maybe it's possible after all. If it is then surely we know about this threat and have found ways to protect against it. We'd be royaly screwed if anybody took out even some of our satillites. It's one of our advantages and we use it like leverage.

Well in my opinion all they did was tag the satellite that they knew the orbit of, and knew the transponder signal, they knew what wavelengths to home in on, besides they did not disable anything they tagged it once for 1 second and one more time for 10 seconds.

However, it is 10 years ago, but it still does not answer any of the dilemmas thelibra and I presented.

I never said it was impossible to tag a satellite with a laser; we do that all the time.

What I find improbable is that China has the technology to hit a supposed spy satellite with such accuracy, at the speed and distance considering the error margin and the size of the target and distortion our magnetic field and molecules in the atmosphere presents, and rendering it unable to record. (I.e. blinding its optical lens)

In addition, a very interesting find I made reading you links.

This was an old small communication satellite in decaying orbit the size of a refrigerator only 400 kilometres up, meaning it had not even left our thermosphere.

Also a correction, I made a mistake in my post claiming that satellites orbit around 40000 kilometres that figure is inaccurate it is more like 4000.

lol Please, believe whatever you like but the fact remains that this is old technology at least a decade old.

Does China have the technology? I don't know for sure but it's far from improbable.

Do our black project satellite have low observability characteristics? Maybe, I have no idea really.

Can we hit a 3 foot reflector on the moon with a earth based laser? Yes and we have for the last quarter century.

Do we have killer lasers that can shoot down missiles traveling at speeds approaching mach 4? Yes

Can the US hit an orbiting satellite with a laser? Yes according to the 1997 DoD briefing.



[edit on 28-9-2006 by kinglizard]

"The Chinese are very strategically minded and are extremely active in this arena. They really believe all the stuff written in the 1980s about the high frontier," said one senior former Pentagon official.

Second Source

It would appear that
Rumsfeld had a point. This is more proof that we need to enhance our capability when it comes to space-based weaponry and potential enemies’ ability to disable them from the ground. This is a space race that we can ill afford to loose. The opposition to being farsighted in regards to our defense against future aggressors will get us all killed if they don’t wake up to reality. This mindset that if we run around with crystals in our pockets our enemies will leave us alone can only lead to our defeat in the future. Burying our heads in the sand is not the answer.

Originally posted by kinglizard
lol Please, believe whatever you like but the fact remains that this is old technology at least a decade old.

NO, it's not old
the US did not successfully blind its own satellite.

and the difficulty of this project is not whether one can build a laser shooter, it is actually how to find the path and focus of the target satellite and find the corrected spectrum and otherthings,
in this case, the US already know all those info.

The 1997's test was far from building an actually working device that can blind enemy satellites during warfares.

You have continuously ignored the points I have made, discarding what do not fit you view. I cannot debate in that manner.

We do not posses killer lasers that shoot down missiles like you are imagining, what we do have is a very weak focused laser that over time can heat up the structural chassis of a potential missile causing it to fall apart. (IN THEORY)

Bit raiser made some interesting points I could actually reflect on in another thread regarding this subject, and I would say that after careful consideration I agree with him.

My point is that the dancing particals (the element required to apply heat and thus damage) is NOT REQUIRED (or even desired) by this system.

It's just light. It's a bright enough light source to blind a camera looking in it's direction.

Infact, because you only need to spam the satellite with enough light to block out naturally refected light, the system my not even require knowing where the satellite is OR the abillity to track it. If your laser is powerful enough, you could difuse it at it's source to create a large cone that would act like an umbrella. This would blind any camera pointing in the general direction of the laser's source. That would be in-efficent, but doable.

Personally, if I were to implement a system like this, I would create a hybrid between tracking and spamming to maximize efficency. A broad cone that fires into the trejectory of the satellite and uses some very basic math to predict it's path. Hell, I've writen more complex code for computer games!

The only really hard bit is seeing the satellite in the first place. Those things are small and fast moving, so detection is difficult. That said, China has it's own satellites and it's no great leap to assume that some of them are likely equiped to look for other satellites.

Reguardless, the important thing I'm trying to get across is that this system doesn't have to damage anything in order to work. This is no more an "attack" than a security guard shining a flashlight into your face when he catches you trying to sneak into someplace you shouldn't be.

they are using cheese lasers its quite obvious if you take a close look at the satalite in accordance with china and the time of day the sattalites are inturupted

Bit raiser made some interesting points I could actually reflect on in another thread regarding this subject, and I would say that after careful consideration I agree with him.

It is also my understanding that a "wide beam" is used for sat blinding. With a powerful laser there is no need to keep it focused to a small beam when simply trying to blind the satellites.