Warships May Get Lasers For Close-In Defense 482
King Louie writes "Raytheon and the US Navy have successfully tested a ship-borne laser capable of shooting down aircraft. Video at the link shows the 32-kilowatt solid-state laser shooting down an unmanned aerial vehicle. The technology is apparently mature enough to be deployed as part of ships' short-range missile defenses, a role currently filled by the Basic Point Defense Missile System (based on the Sea Sparrow missile) and the Close-In Weapons System (based on a 20mm Gatling gun)."
Re:Yeah. (Score:1, Informative)
You're being too literal. It could be used for anti-missile defense.
Megawatts? (Score:1, Informative)
The article says kilowatts.
32 kilowatt!!! (Score:5, Informative)
32 kW, not MW, thats kilowatt, not megawatt.
Numerous advantages (Score:5, Informative)
There are numerous advantages to using lasers instead of traditional weapons:
*) Longer range
*) Better accuracy
*) Unlimited ammunition
*) No pollution from spent weapons
Re:Yeah. (Score:3, Informative)
"The technology is apparently mature enough to be deployed as part of ships' short-range missile defenses"
Only a few orders of magnitude off... (Score:5, Informative)
...shows the 32-megawatt solid-state laser...
From TFA:
...which is made up of six solid-state lasers with an output of 32 kilowatts that simultaneously focus on a target.
As my stat mech professor once said, "but hey, what's a few orders of magnitude between friends?"
Re:What if it's foggy? (Score:3, Informative)
Re:32 kilowatt!!! (Score:3, Informative)
I'd be very curious to know the output of the units on a nimitz class carrier.
and after a quick wiki article..
two 104 MWe units. Very nice.
Re:Question... (Score:3, Informative)
Re:Numerous advantages (Score:3, Informative)
Perfect mirrors, with not a single imperfection that will melt them in a microsecond, which are completely dust free in spite of being outdoors.
Re:Question... (Score:3, Informative)
The usual response here on Slashdot is that since most of the mirror surfaces you're likely to get are irregular/imperfect, the heat from the laser would likely ablate (burn off) any mirror coating you have before it would do what you're thinking. In the case of chrome, it's not a perfect mirror, and it wouldn't work.
I think you would need a very perfect mirror surface, and even then I get the impression it wouldn't have the desired effect.
Re:Numerous advantages (Score:2, Informative)
A laser would require energy, how much energy, I don't know how much but I doubt it is a pair of double AA are powering the thing so lets not pretend it has unlimited ammunition.
32 kW according to the fine article, and if the laser is mounted on a carrier it will be a pair of Westinghouse A4W nuclear reactors powering it. The number of shots one of these things could fire won't be limited by the power plant, that's for sure. On a cruiser or destroyer it will be powered by the ship's service diesel generators. Sure, the ship could run out of JP5, but at that point it's dead in the water anyway because that's what the gas turbines that turn the screws run on as well. Long story short the power source is the last thing we'd need to worry about.
Re:Question... (Score:3, Informative)
Re:Priorities (Score:2, Informative)
So - we should just give the money to the people without jobs?
Only if you want a line millions of people long once they hear you are handing out free money. No, I think the point is the government shouldn't have the money in the first place. Perhaps if the people who create the jobs had a little more money (in the form of paying a little less taxes), they'd be able to create more jobs.
But then again what do I care. It's not as if I pay income tax anyway. Thank god I'm not a US citizen - no matter where you guys live you have to pay for crap like this, it's the law.
Re:Numerous advantages (Score:5, Informative)
From the article :
Although Booen says that for security reasons he cannot divulge the distance at which the laser-based systems can shoot down incoming threats (or the UAVs' altitudes during the Navy test), he notes that the military would not be interested in the new laser technology if it could not at least double the range of existing weapons.
That would imply that at least in this case it would give longer range and higher accuracy.
Also, regarding the lasers:
The Phalanx--a rapid-fire, computer-controlled, radar-guided gun system--used electro-optical tracking and radio frequency sensors to provide range data to the LaWS, which is made up of six solid-state lasers with an output of 32 kilowatts that simultaneously focus on a target.
So they use the already-existing Phalanx platform for targeting and tracking. Also also:
The weapon combines a 20-millimeter Gatling gun that fires at a rate of either 3,000 or 4,500 shots per minute, with radar to search for and track targets
So it seems that the new laser weapon will supplement or replace the existing gatling gun, and they indicate the laser will more than double the effective range of the setup.
Re:Yeah. (Score:3, Informative)
If the missile is moving at mach 5, it really doesn't matter if the bullet is stationary or at mach 1, most of the KE is supplied by the missile itself.
Re:32 kilowatt!!! (Score:4, Informative)
And why don't we deploy those kind of units in the municipal power grid?
Actually they do just that in case of an emergency. There are connectors and such that can attach to a power grid in times of emergency so that the ships can provide power to emergency services and so on. I believe they've actually used them a few times.
As to why they don't make these types of units a regular part of the grid it's because they have much different requirements than a land-based power plant. The price per watt is much higher for a power-plant on a ship than one on land due to size, weight, combat-worthiness, and many other factors.
Re:Yeah. (Score:5, Informative)
This laser is 32kW, and it's already pushing the limits of solid state laser tech. 32MW laser is nowhere in sight for several decades, unless we make major breakthroughs in materials needed, not to even talk about power draw, which for current laser at 20% efficiency would be around 160MW for your suggested 32MW laser. And with increased power, the efficiency of laser installation is likely to decrease significantly.
You're gonna have some pretty hardcore power cabling, cooling system and a nuclear reactor to power that kind of a thing, not to even mention the epic size of a weapon. Cooling system alone will probably be bigger then a modern missile silo.
This replacing a small, localized and largely autonomous system that performs better in most conditions? I think not.
Comparing this to Sea Sparrows or any other ship based medium range SAM in any way other then augmentation is just plain foolish anyway. This caps at a few kilometers, depending on weather. It's a potential kinetic CIWS replacement (i.e. phalanx). It's in no way even a contender for SAM CIWS replacement. Not even because the tech isn't ready, but because the tech is unsuitable by default. Weather and fact that Earth is a sphere will make sure of this.
Comment removed (Score:3, Informative)
Re:Numerous advantages (Score:5, Informative)
GP said "Better accuracy"
P said "No"
Lasers ARE more accurate than projectiles, wind doesn't shift a laser's course. The need for greater accuracy with a laser is a power issue, not an accuracy issue. Nobody is arguing yet that lasers are fully ready and powerful enough to replace projectiles, just that we are getting closer.
GP said "Unlimited ammunition and No pollution from spent weapons"
P said "No"... to both
Again, solid state lasers, which are the topic of the article have their waste and ammunition limited only by their power source. Seeing as these are being tested for naval deployment, it's a pretty sure bet the power source for these in any significant deployment is going to be a nuclear reactor. That means the "ammunition" supply cycle for the ships lasers will by measured in years, so yes, that is as good as unlimited. The waste is also limited to the size of the reactor vessel, again over that same number of years. Not terribly shabby. The only obstacle is getting the power on the lasers up high enough to be useful even in foggy/cloudy weather.
Re:Yeah. (Score:4, Informative)
Payload. Much of energy is wasted as such lasers have very low efficiency. You will have to dissipate around 4-5 times the energy you get on laser's focus around the laser itself as waste heat. When it's lasik, you have nice and low power ratings which can be cooled easily. When it comes to large powerful lasers, it is simply not doable with current materials. Your installation will simply melt down or even vaporise itself if you have to output the energy needed to burn through metal in that kind of a small time window.
Re:Numerous advantages (Score:5, Informative)
The Phalanx system by itself has a very good RADAR system behind it, and the outgoing bullet stream is identifiable by that RADAR. Basically, it becomes a very accurate system because the firing system doesn't need to know anything about wind, etc. It just pushes the az/el/range of the outgoing doppler objects (bullets) to the az/el/range of the incoming doppler objects (bad things). Any effects of wind, etc are just taken into account automagically.
Re:Numerous advantages (Score:3, Informative)
Since the only Naval ships which are, currently, nuclear powered are aircraft carriers and submarines I think it's a safe to say that most naval laser weapons will be getting electricity from a non-nuclear power source.
So their ammunition will only be measured in days, or possibly weeks, not years. But that's still far better than the ammo situation of the existing Phalanx, which has ammo for less than a minute of continuous firing.
Re:Numerous advantages (Score:5, Informative)
GASP! this is what gets moderated as insightful these days!
So the laser took three seconds to burn a whole in the rather unreflective fuselage of the target drone! but would melt anything but a 'perfect' mirror in microseconds. But let us humor this point one moment further and calculate 32kJ / 3E6 = 0.032J ... some of my less intense emotions about this thread have more energy than that!
And further down the thread these brilliant commenteers further apologise how 'perfect' the mirrors inside lasers are and their so special you cant possible coat anything but laser components like that. Narrow bandwidth my rearend!
Try burning a freaking hole onto a polished (90% reflectivity) aircraft grade fuselage with your now 3.2kW laser. Absoption, melting point, mass, heat capacity, heat conductivity... I'll leave it all as an exercise to these enlightened enthusiasts.
Humbly Yours
Pissed off physicist
Re:Tracers work both ways (Score:3, Informative)
And therein lies the major problem with this laser. It took several seconds to blow up a drone, which presumably isn't optically shielded (ie. shiny).
"Shiny" materials typically provide zero defense against high powered lasers. They need to be specialized materials to become effective.
Not to mention that the faster the missile travels, the greater the atmospheric cooling.
That's true to a limit. Given that most anti-ship missiles travel at multiples of mach, the friction generated at this speeds typically, considerably heats the missile's surface. Furthermore, minor deformations at such speeds can cause catastrophic aerodynamic stresses and failure.