Well its about time...
We are 10 years into the 21st century, I want my raygun damnit.
The USA's famed ray-cannon jumbo jet, the Airborne Laser Testbed (ALTB), failed to shoot down a ballistic missile in a long-delayed live test last week. The ALTB nose laser turret. credit: MDA You miss one missile... The US Missile Defence Agency (MDA), in charge of the test, saw fit not to announce the test or its failure …
We are 10 years into the 21st century, I want my raygun damnit.
But not the one they hit...
I'm suspicious about the way airborne laser stories always emphasise the limitations and suggest it will never work. Is it really that unusual for military weapons to have toxic fuel and exhaust? And how does a 2-airplane reload fit into one smaller airplane.
So everyone writes it off as a loser project but then at the right moment they can rub their hands and go "Muhahaha observe my Fully Operational Deathstar."
You are probably thinking of the C5 Galaxy. The C17 is big, but no Jumbo. The C17 reportedly landed on a carrier, which I do not think a 747 could manage
Cracking rewrite of the wired article there.
Are you a bit busy with the radio career nowdays? Your appearance on Radio 4 a week or two back (assuming it wasn't a namesake) hasn't gone unnoticed. Though I was disappointed that you haven't got the brummie accent that I had for some reason expected.
>>"Cracking rewrite of the wired article there"
I'd have thought that most of it could just have been cut-and-pasted from previous Reg articles - chemical lasers, toxic fuels, electrical ones will be better, etc...
Have they hired Valerie Singleton to run their Defence department?
"Here's one I prepared earlier."
Remember Ronald Raygun and his star wars missile defence program? The tests were totally fake. They fired the lasers at large cylinders that were held down by cables under very high tension so that the slightest damge would cause them to collapse spectactularly.
At least the fact that these tests have failed would seem to demonstrate that it's a real test of the technology.
If they're going to be using the electrical lasers at altitude I'd have thought there would be plenty of very cold air outside the plane, and moving past it at a several hundred miles an hour. So possibly not too much of a problem directing some of it into cooling the laser.
The fact that they can cool it effectively isn't the issue - its the fact that the energy generating the heat is wasted *as heat* and not stimulating more nifty photons at the target.
If more than 50% of your energy is being wasted (and I'm thinking probably 90% waste or greater) that multi-megawatt beam is going to require a gigawatt nuclear power plant. How are we going to attach that to a shark's head?
So how hard is it going to be to chrome plate your missiles?
How does a laser beam burn a mirror 50+ miles away without burning the mirror used to point the beam at the missile?
As for the comment about an ample supply of air for cooling electric lasers, the missile also has an ample supply of air for cooling itself.
the energy absorption ratio between a military grade multi layered mirror and a high reflective simple coating is magnitude of order. (for the specific wavelength of the laser). Basically you can have a mirror system that can handle the ray but still fry a simple coated missile.
50+ miles of air on a large part of the spectrum suppose little more than a few percents of loss, mostly due to scattering.
The idea is to generate a short pulse that will make meaningless any cooling system.
Still your simple coating make necessary to increase the energy output ~X100 in order to cause same damage to your coated missile compare to a standard one.
if you thinking in add a multi layered mirror to the armour of your missile, you need to be sure that your enemy only use a specific wavelength for his laser toys and known well this magic number. (multi-layered mirror are build for a specific wavelength)
I don't believe that the laser is in the visible spectrum or that chrome plating reflects wavelengths significantly out of said visible spectrum.
Best to supply a hundred dummies running with each missile. These start with the missile and are released above the atmosphere. Each is a radar reflector, as fitted at the top of all good yachts.
A good point, and this also applies to lasers based on ships which can use water cooling (and it's probably safer for a ship to divert engine power to the laser!).
I think that the boffins are concentrating on improving the efficiency of electric lasers though, as this solves the power supply and cooling problems at the same time.
I can't help thinking that they might get similar results with a stern look, and I'm pretty sure Supernanny would work out cheaper. Got to be worth a go, right?
<-- Megaphone to shout the threat of the "naughty steppe"
Great, now I can't get the image of Supernanny strapped to a jet engine on a collision course with an ICBM out of my head... And I am as of yet undecided whether it is hilarious or deeply disturbing...
Use the excess laser energy to heat up water to stream, run a turbine, then use the leccy generated to feed back to the laser.
There, fixed that for them.
Where's my patent?
While possibly viable, the electricity would have to be stored in batteries - most military lasers operate at very short pulses (< 500ms), not giving enough time for H2O to convert to gaseous state, expand through a turbine system, and drive a generator in time for the laser to utilize that electricity generated for the same pulse (or even a subsequent pulse in the attack set)... If the plumbing system could be made lightweight enough to still take the high pressures involved safely on a aircraft.
Most of the heat is absorbed by a paraffin coat at present, which takes much more heat (at MUCH safer pressures for an airplane) than a heavy steam plumbing system. Either way, efficiency increases are better bang for the buck.
I am curious, how does a laser work to destroy its target?
I have wondered this for ages, hopefully somebody will enlighten me?
With a bullet its obvious, it hits its target, deforms on entry, and punshes a nasty hole through...
But what is the laser equivalent of this?
Does the target surface melt / instantly vaporise / atomise / plasmarise / explode... all four... repeatedly?
How does pulse duration / wavelength affect the outcome?
Is one wavelenth better for flesh & another for metal.... so many questions!
...the beams narrowly miss the target and set off small fireworks hidden in the walls nearby. And are rotoscoped in during post-production.
...and yes, I am the man who thought "Die Hard with a Vengance" was a documentary and changed the security in airports accordingly. Here, let me just fold my jacket into this tray for x-raying...
Very small and very light but very fast and there are billions of them :-)
Seriously, photons are quanta of energy, when hit by photons electrons assume higher-energy orbits, the atoms become excited, excited atoms mean heat and greater reactivity. I think.
But I think it heats the body, until the highly volatile fuel goes pop.
Hence the need to hit it in the boost phase when it still has lots of highly volatile fuel.
The target destruction can be achieve by:
the kinetic effect produce by the plasma formed at the immediate impact surface. ("plasma punch")
structural damage produce on impact. ("case slicing/drilling")
generating an ultra heat section that force the missile fuel to burst. ("melting")
wavelength is only relevant counter measure for that wavelength. most high powered laser can fry any opaque surface.
to same energy output , shorter pulse increase the plasma punch effect and facilitated the heat concentration.
as opposed to hitting it in the free fall ballistic phase... where it will still hit its target.
"an operational fleet of ABLs would be a huge and expensive effort."
Unlike the rest of the US Military?
Laser puts out lots of energy in a short time.
The energy heats up the outer skin of the target and melt/svapourises it.
If the target is the thin skinned wall of a highly pressurized liquid fueled ICBM fuel tank then it goes pop - if it's anything stronger it laughs at you.
The choice of wavelength is limited by something that isn't absorbed by the air/water vapour between you and the target. Shiny metal is roughly the same reflectivity across most of the practical wavelengths so target doesn't really matter.
Main defence is either to put some extra layers of insulation on the target so that these can be destroyed by the laser without doing any real damage - or simply shotting down the lumbering 747 that is flying in slow level circles around your missile launch site.
The only advantage of a directed-energy weapon(or launch systems) is the much larger power supplied by an electric grid, but it is not compact by any means. For instance, you could purpose-build a nuclear plant to power a laser or another kind of electric gun (launcher) to access near-limitless power; you can direct a lot of power in a small space, as opposed to a chemical solution. But for compact systems, chemically-powered weapons and engines are vastly superior.
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