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General Science => General Science => Topic started by: Pseudoscience-is-malarkey on 23/11/2015 00:49:51

Title: Is there a way to block laser beams to prevent blindness?
Post by: Pseudoscience-is-malarkey on 23/11/2015 00:49:51
As far as I know lasers are not yet at the point where they can replace bullets, but that doesn't mean they're not dangerous. There is a disturbing trend going on in the United States and UK, and other parts of the world, where people (mostly young adults) are shooting laser beams at aircraft with the expressed purpose of crashing them like wild game. Why is it that the police, military, private industry, et cetera, have not invented something that can protect aircraft from being blinded? Is it near impossible?
Title: Re: Combating Laser Beaming
Post by: alancalverd on 23/11/2015 01:03:23
It's not the aircraft but the pilot that gets blinded. Since lasers have a very narrow bandwidth it might be possible to fit a filter to the windscreen but the only effective deterrent is to prosecute anyone caught doing this for attempted murder.

He might get 6 months' suspended sentence in a UK court, unless he has overfilled his dustbin, failed to pay his TV licence, or called a workmate "darling", in which case he will be lucky to get out alive. 

In many US states, endangering an aircraft carries a mandatory death sentence.
Title: Re: Combating Laser Beaming
Post by: Ethos_ on 23/11/2015 03:06:26
I've often wondered if the windshield on aircraft could be fitted with a one way mirror film which would reflect most of the laser beam giving the pilot some measure of effective safety?
Title: Re: Combating Laser Beaming
Post by: evan_au on 23/11/2015 11:01:54
The main risk is for planes on final descent at night, when the pilot's pupils are wide open, the plane is low (short range), and the pilot needs to see the runway to land safely.

Frequently the main indication would be that the pilots would see a light shining on the roof of the cockpit. This is not so risky.

However, light shone from the area of the airport along the glide path towards the approaching aeroplane would be extremely dangerous.

Fortunately, most of the readily-available lasers are "Class 1", which means that they can't do any permanent damage even at very short range - but even a distraction could be disastrous on final approach. And people doing this for a joke are just as likely to shine their laser at the Police helicopter sent up to locate them.

People importing more powerful lasers into my country without good cause can be fined, and have their lasers confiscated.

In the cold war, when it was feared that a nuclear attack could occur at any time without warning, the US Air Force was concerned that many of its pilots could be blinded by an atomic bomb exploded in the sky. They experimented with windshields having electronically controlled portholes which could go opaque in microseconds to protect the pilots vision.

Another approach was to have pilots wear a pirate-style eyepatch, so if they were blinded by a flash, they could flip the eyepatch over, and continue flying the plane. But that is a bit extreme for commercial flying - two eyes are better than one.

Ultimately it comes down to people being aware of the dangers of laser beams, and taking responsibility for their own actions.
Title: Re: Combating Laser Beaming
Post by: RD on 23/11/2015 11:49:04
I've often wondered if the windshield on aircraft could be fitted with a one way mirror film which would reflect most of the laser beam giving the pilot some measure of effective safety?

It would be very dark from the pilot's viewpoint : like looking through mirrored sunglasses.
Title: Re: Combating Laser Beaming
Post by: Pseudoscience-is-malarkey on 23/11/2015 19:30:52
Herr Alancalverd,

I appreciate your response, but you might want to check your facts. In the U.S. a person cannot receive a death sentence for attempted murder.
Title: Re: Combating Laser Beaming
Post by: evan_au on 23/11/2015 19:34:57
If it has been seen that someone is targeting planes with a laser beam, it is possible for commercial pilots to fly an instrument approach - at least until they pass the area where the laser beam was being used.

This also affects astronomers - adaptive optics can remove much of the atmospheric distortion by sending a powerful laser beam into the upper atmosphere. This can affect planes flying overhead, or even spy satellites. So they have to turn off their laser beam (stop observing) when planes approach, and astronomers have to get permission from the US government about what they are allowed to observe in space (and when).
Title: Re: Combating Laser Beaming
Post by: Don_1 on 24/11/2015 00:47:57
This is a disturbing escalation of this problem.

http://www.theguardian.com/world/2015/nov/23/ba-pilots-eye-damaged-by-military-laser-shone-into-cockpit-at-heathrow (http://www.theguardian.com/world/2015/nov/23/ba-pilots-eye-damaged-by-military-laser-shone-into-cockpit-at-heathrow)
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: alancalverd on 25/11/2015 19:02:06
Herr Alancalverd,

I appreciate your response, but you might want to check your facts. In the U.S. a person cannot receive a death sentence for attempted murder.

My suggestion was to prosecute for attempted murder in the UK - who knows, the criminal might even get sentenced to ten minutes' community service and having to say sorry, but the death sentence for endangering an aircraft was advertised on the security fences of several US airports I visited in the past.

A nice technical solution would be a beam-riding missile that simply flies down the laser beam and delivers a kilogram of Semtex to the source. Or a corner-cube reflector: there's nothing quite like getting your own back!
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Atomic-S on 26/11/2015 02:18:16
Quote
A nice technical solution would be a beam-riding missile that simply flies down the laser beam and delivers a kilogram of Semtex to the source. Or a corner-cube reflector: there's nothing quite like getting your own back!
These sound like ideas that might actually work.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Atomic-S on 26/11/2015 02:20:22
Because laser lights are of very narrow bandwidth, it would seem not inconcievable to devise goggles whose lenses were opaque right around those wavelengths. I am assuming, of course, that lasers are generally available in only a very few wavelengths.  These would dim general vision only slightly.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Pseudoscience-is-malarkey on 16/01/2016 08:43:50



My suggestion was to prosecute for attempted murder in the UK - who knows, the criminal might even get sentenced to ten minutes' community service and having to say sorry, but the death sentence for endangering an aircraft was advertised on the security fences of several US airports I visited in the past.

A nice technical solution would be a beam-riding missile that simply flies down the laser beam and delivers a kilogram of Semtex to the source. Or a corner-cube reflector: there's nothing quite like getting your own back!

Capital Punishment is abolished in Britain, and has been since 1964.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: alysdexia on 17/01/2016 13:47:54
What's next?  Floodlamp beams, halogen lamp beams, LED beams, mirror beams, death ray beams?

http://google.com/search?num=100&q=photochromism+%22visible+light%22
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: evan_au on 22/04/2016 12:58:02
Tonight someone illuminated my plane with a green laser pointer as the plane approached Sydney airport.

Fortunately it was a bit off to the side of the glide path, but it was still quite bright. Not bright enough to make you blink, but it might degrade your night vision if it caught you by surprise.

I hope the pilots kept their eyes on the glide-path...
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: syhprum on 22/04/2016 14:15:42


If the problem was acute the pilots direct view could be replaced with a television system where only one of several redundant cameras each incorporating different filters would be the only things risking damage.
I would expect such a system to introduce additional dangers and only be used if the problem became acute.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: syhprum on 22/04/2016 14:27:06
I think Alan underrates the severity of the English law in a recent case a defendant accidently killed a police officer trying to stop his car  in a case where the charge would normally have been one of causing death by dangerous driving was charged with murder and despite the disagreement of the jury the was convicted of manslaughter and sentenced to 21 years imprisonment.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: alancalverd on 22/04/2016 16:49:31
Indeed. Killing a policeman is considered as heinous as laughing at a woman in high heels. I have at least one record of a motorist receiving a £50 fine for killing a cyclist (but not exceeding the speed limit whilst doing so), whilst on the same page the newspaper reported a motorcyclist being fined £500 and banned from driving for a year, because he was recorded as doing 150 mph on an empty road at 3 am, and thus inconveniencing the police who couldn't keep up with him.

Whatever statute law says, criminal justice changed in 1979 when the UK police force became an arm of political government.   
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Tim the Plumber on 22/04/2016 21:53:13
I have a welding mask which becomes dark the instant I start arc welding. It was a cheap thing to buy.

The speed of it is good enough that there is no chance of damage to the eye from the extreme brightness of the arc welding process. Clever stuff. I don't know how it works exactly.

https://www.amazon.co.uk/Design-Darkening-Welding-Helmet-Grinding/dp/B01AOTJDRW/ref=sr_1_2?s=diy&ie=UTF8&qid=1461358346&sr=1-2&keywords=welding+mask
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: alancalverd on 22/04/2016 22:36:16
A nice thought, but probably in need of some further development.

Pilots were discouraged from wearing photochromic spectacles because whilst some can darken very quickly, they are slow to recover. Excellent as you climb through cloud into the blue bowl (where there's not a lot to see anyway), but descending to your destination can be something of a lottery.

Possibly a good idea for a 2-man crew, for one to wear photochromics on final approach, or even to make half the windscreen photochromic, since most two-pilot missions will use an instrument approach down to very low level, but those of us in sole command of an aircraft approaching a visual-only field are a bit vulnerable, and I'm sure the idiots who play this game would be just as delighted to kill a family in a Cessna as a hundred paying punters in a 737. That's certainly the proven case near here.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: wolfekeeper on 26/04/2016 21:00:37
Personally I think that laser pointers should be made illegal in the UK; there's easier ways to entertain cats.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Pseudoscience-is-malarkey on 27/04/2016 00:25:34
Personally I think that laser pointers should be made illegal in the UK; there's easier ways to entertain cats.

Our perhaps heavily restricted, like guns.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Tim the Plumber on 30/04/2016 13:58:42
Personally I think that laser pointers should be made illegal in the UK; there's easier ways to entertain cats.

Apparently it's not the common laser pointers and levels, it's actually high powered things that have no use outside physics labs.

And yes surely they will be banned/restricted.

Back to my welding mask; Not only does it darken instantly (well, to my perceptions) but also undarkens again when I stop welding. Magic thing.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Bored chemist on 02/05/2016 13:01:32
Herr Alancalverd,

I appreciate your response, but you might want to check your facts. In the U.S. a person cannot receive a death sentence for attempted murder.

My suggestion was to prosecute for attempted murder in the UK - who knows, the criminal might even get sentenced to ten minutes' community service and having to say sorry, but the death sentence for endangering an aircraft was advertised on the security fences of several US airports I visited in the past.

A nice technical solution would be a beam-riding missile that simply flies down the laser beam and delivers a kilogram of Semtex to the source. Or a corner-cube reflector: there's nothing quite like getting your own back!
Let me know if this ever gets adopted. There are a few buildings I'd like to blow up*, and some of them are near flight paths.
All I have to do is put a laser pointer on their roof with a timer switch.

*not really, but others will have the same thoughts,and they would make use of it.
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: alancalverd on 02/05/2016 13:40:47
Pilots' lounges are notoriously worse than dentists' waiting rooms in their selection of magazines. The worst yet was "Jet Life", aimed presumably at passengers with more money than sense and advertising a bikini for $30,000 - what I would call a "new engine" rather than a swimsuit. But I digress. The only other reading matter seems to be accident and incident reports - the "Grace of God" shelf. And it was there that I found the answer, which apparently has been around for a couple of years:   

http://www.laserpointersafety.com/news/news/other-news_files/f070b6d15f32f14588a8759456c934cf-321.php#on (http://www.laserpointersafety.com/news/news/other-news_files/f070b6d15f32f14588a8759456c934cf-321.php#on)

advertises commercially available narrowband protective spectacles, with apparently 80% out-of-band transmission. So it's all down to cost/risk/benefit assessment and whether you can ignore the banter of colleagues offering white sticks and dogs as you put on your shades for a night sortie. Perhaps the answer is a fighter-style bone dome with antilaser visor, but wearing one in a vintage Cessna looks as daft as spending a year's salary on a bikini....
Title: Re: Is there a way to block laser beams to prevent blindness?
Post by: Tim the Plumber on 02/05/2016 14:02:37
LOL!

I have the answer to the problem of the anti-laser glasses;

Very highly trained guid dogs! Or in this case doggy pilots.

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