20 miles isn't far for a 32 megawatt laser I think. 32 megawatts is a lot.

Nice. So, we don't have money for the unemployed, for the ill, or even for veterans benefits, but we can afford laser systems to shoot down planes for imaginary invasions.

Seventy percent of the defense industry is a private set of corporations whose economic incentive is to discover (or invent) threats, and then sell the government the contract to fight this imaginary enemy. Sounds like a nice recipe for solutions that exacerbate the underlying problems, and not by accident [go.com].

Not really. Lasers are strongly attenuated in air, especially in the humid air in marine environments. Trying to get around this problem is the reason we're just getting weapons like this now, as opposed to thirty years ago, and even now they're limited to short ranges.

Yes and no. In order to heat up the target's surface enough to cause destruction, you either need to focus the laser on the exact same spot for long enough time, or just crank the power up and/or widen the beam enough so that it doesn't matter. The first has proven almost impossible, and so we've resorted to the second.

No. There are two kinds of lasers in consideration by the military: chemical and solid-state. Chemical lasers need tons of (duh) chemicals to form the reaction that generates the laser light, and when you run out, you're done shooting. Solid-state lasers require heavy amounts of electricity, which needs to come from somewhere.

Again, no. Chemical lasers leave behind highly toxic waste products when the reactants are expended; that's the main reason why they're not in heavy use in the military today. Solid-state lasers leave behind pollution from whatever power source you use to generate the electricity.

I'm not saying lasers are awful tools, they're certainly useful in specific applications. But they're not the Wunderwaffen you're making them out to be.

Seems like they had to hold the laser on the target for a long time until it worked. If you can keep a laser beam on target that long, you might as well use the laser to guide an effective, high explosive round to it.

Depending on the duty cycle of the parts in the weapon laser vs. a painting laser, it could well be far more efficient, from a logistical point of view, to use this system than to expend some consumable weapon guided by a painting laser. Never underestimate the importance of logistics.

It also could be more reliable, as you just have to keep the laser operating and on target, rather than keep a laser operating and on target and avoid a failure in the launching, propulsion, guidance, or warhead system of the separate passive-laser homing missile. Given the consequence of failure with you point defense system, even small differences in reliability can be a big deal.

A corrupt defense industry is one thing, but opponents who would like to destroy warships date back thousands of years.

Ships are (very) high value targets, which obviously merit beam weapons to defend against attack, and particularly so as UAV systems proliferate.

This offers far less hope against missile swarms and fast cruise missiles then lead-spewing kinetic weapons. With this you need to affect a single point on the missile from the front for quite some time to get results. If it's a fast cruise missile with mach3-mach5 terminal approach, laser is useless - it simply won't have enough time to do damage. So is kinetic CIWS. Missile based CIWS has a chance as it can engage at decent range and score a one shot kill.

Against swarms, this is even worse. You have to burn every individual missile, retarget and burn next one. Even if by some stroke of luck you succeed in this titanic task and can get missile terminated in say 3 seconds of burning it (completely impossible with laser as weak in tests), all that opponent needs to do to counter it is to program missile to go into a spin in terminal stage, making it impossible to focus at a single point of the missile. Or install a high-albedo tip. Or just attack in a stormy weather where laser energy will dissipate into water droplets long before it hits the missile.

Kinetic CIWS like phalanx/kashtan on the other hand actually have a decent chance of shooting slow and small missiles of this kind down, as they can usually kill a missile in one-two hits and are largely unaffected by weather conditions. Missile CIWS are better, but tend to get overloaded with sheer numbers.

All in all, this is just a PR stunt to show US taxpayers that their money is spent on yet another hollywood-style toy with little room for real life applications. This is a weapon for space age and space warfare where weather does not exist and laser can be effective at far greater ranges.

...counter the asymmetric warfare ...

"Swarm[ing] our aircraft carriers with airplanes and missiles" is NOT "asymmetric" warfare. That is your basic nation to nation warfare, where someone has the guts and sense of honor to fight in compliance with the rules of the Geneva Convention. Asymmetric warfare would be someone floating a civilian boat up the the warship and setting off a suicide bomb. Google "USS Cole (DDG 67) on October 12, 2000" for an example.

A 32 MW laser would be a fine alternative to a gatling gun - 32 MW is a lot of power, you don't need to paint a single spot on an incoming missile. The laser in the video was just a few kW, and so took several seconds to kill a drone. The gatling guns also kill one threat at a time, and it takes time to get a few rouns into an incoming missile (the first few rounds usually miss, the gun tracks both rounds an missile on RADAR and corrects fire until it gets it right), and once you do the remains are still a serious threat that will cause real damage and casualties. A laser has a lot more potential to cause a catastrophic kill of the missile, where the remains aren't nearly as threatening (and all the fuel is gone) when the ship is hit.

But gatling guns deal with threats that make it past the missiles, and the advantage of the Sea-Sparrow-based defenses is you can launch all your counter-missiles rapidly against many incoming threats at once, at medium range. A laser cannon might grow into that role, but it would be much harder (and have enormous power demands, but then we do need to protect ships with nuclear power, so maybe that's OK).

The other nice advantage of a solid-state laser is that it's not used up after one engangement. The gatling guns require significant service after minimal use. Can the Sea Sparrow-based CIWS can be "re-stocked" at sea?

"Yeah. Too bad, though, since dropping gravity bombs from planes had its heyday during 1935 to 1955."

There have been more (tonnage) dropped since 1955 than in the 2 decades you mentioned. (And thas even discounting JDAM's and laser guided gravity bombs. Of course nearly all of it was dropped by US or 'Allied' planes.

"Nobody's tried doing that for a long long time."

Not against the US navy, since it has always had air superiority since after the Vietnam war. However The Royal Navy suffered many hits during tthe Falklands war in 82. Only one warship was sunk by an exocet missile.

"What you do is stand off 20 miles and shoot a missile at the ship"

Hopefully the laser can hit the missile too. But I doubt anyone could get within 20 miles of a carrier battlegroup if it was in open water.

Bullets and lasers deliver this energy differently - the bullet's energy is transferred to the target in a much shorter time (milliseconds, I assume) which produces more chaotic results than the laser (for the same energy), which is waiting until the target ignites or a hole forms, wrecking the aerodynamics. Even so, I was curious how the energy payloads stack up.

A 32 kilowatt laser delivers (not surprisingly) 32kJ during a one-second pulse. I'm not sure how long this laser pulses, but from the video, it appears to be several seconds.

By way of comparison, a .50 Browning has a muzzle energy of 15kJ, which is about the same as a half-second exposure to the laser.

The Phalanx gun which this the laser purports to replace, on the other hand, shoots 20mm rounds - these could weigh 100g [wikipedia.org] each, for a muzzle energy of 30.25kJ, comparable to the one-second pulse. Of course, the Phalanx shoots 50-75 rounds a second [wikipedia.org], for a total muzzle energy/second of firing of a whopping 2269kJ.

By coincidence, this is the same as the food energy in two Big Macs.

Well, if you want to invest in more war instead of, say, better infrastructure, or more education, that's a choice you can make. A stupid one, in my opinion, but a choice nonetheless.

That's my point. This cheaper laser takes too long to destroy the target. An HE round destroys it instantly (at greater cost, obviously).

Plus, since it's new technology, they'll sell it at a 1,000,000% mark-up. I know, because I'm a defense contractor ;-)

First of all, I'm not trying to denigrate anyone's service. I know many people feel that the wars in Iraq and Afghanistan are justified, and I blame myself as much as I blame the politicians and businessmen who exploit our armed forces for their own goals and benefits.

But what if you had been asked to perform your duty to your country by educating poor children (in foreign lands or at home), or to help build roads or work with communities to reduce drug problems, mentor troubled teens, or become a surgeon and work for a lower wage in a government hospital?

It seems odd to me that the same people who think using force and violence to impose our will on foreign nationals - and putting their own life at risk in the process - is patriotic, while any of the previous paragraph gets relabeled as communism or some other misnomer. A battlefield medic is a hero, while a government paid surgeon would be considered incompetent, even though they are the same thing. The whole thing seems nonsensical to me.

Bullets and lasers deliver this energy differently - the bullet's energy is transferred to the target in a much shorter time (milliseconds, I assume) which produces more chaotic results than the laser (for the same energy), which is waiting until the target ignites or a hole forms, wrecking the aerodynamics.

While energy weapons are gosh-wow sexy, their effects depend on maintaining the beam on the incoming missile for some undetermined length of time, until it either ignites the fuel or destroys the guidance systems. As modern ship-killer missiles tend to be supersonic, keeping the beam focused on a particular spot on an incoming missile is far from trivial, and of course will vary from missie to missile, so the defensive sytems have even more variables to account for. Phalanx and other gun systems use radar to track the incoming missile as well as the stream of outgoing rounds, and adjusts the aim until the tracks intersect.

Another problem is that destroying the missile's guidance system alone won't cut it. If it's already locked in the terminal phase chances are it will be blind, but still hit the target. This is the major reason that CIWS tend to use multi-barrel cannon with extremely high rates of fire (20mm/6,000 rounds per minute in the case of Phalanx, 30mm/4,000 rpm in the Dutch Goalkeeper system, which is built around the gun used in the A-10 aircraft). The intention is to cause as much structural damage to the incoming missile as possible, either destroying it or rendering it incapable of remaining on course, and with a missile like the SS-N-19 Shipwreck, which masses 7,000 kg and travels at Mach 2.5, even if the guidance systems and warhead are nullified, impact, even from large fragments, can still cause catastrophic damage to the defending vessel.

Then there's the energy requirements of a powerful laser, along with the transmission and control systems, massive cabling, fire-suppression, safety etc., versus self-contained units like Phalanx or Goalkeeper which basically just plug into a hole in the deck (oversimplification of course, but not by much). I am not a weapons expert, but personally I don't see the advantage of energy weapons over traditional gun systems for close-in defense.

A few points:
The fiber lasers used in the demonstration can approach 80% efficiency.
A more realistic 500KW would shoot just about anything down and would easily be powered by ship or grid.

Technically many high-speed surface ships run on gas turbines rather then diesel with diesel generators as emergency backup. While you probably could put them on nuclear power source, that typically would not be a good idea - the hulls are usually designed to run on specific engines designed for the hull, and while it is certainly within conceivable realm of possibility to replace such turbines with specially designed nuclear reactor and electric engines, it is extremely unfeasible in most cases, causing massive cost overruns and creating many potential weaknesses in the design.

In most cases, surface ships really are best powered by gas turbines. Just look at the currently built ships and you'll see this fact plainly.

Even more pertinently, it's completely useless against a diver with some C4 who's blowing the hull out of some cruise liner full of rich fat people. Destroyers, aircraft carriers, submarines - they're all great for fighting another country, but we're rapidly reaching the point where no country could practically declare war on another without economically crippling itself.

The future of warfare is between governments and small, mobile rebel groups. Terrorists, guerrillas, freedom fighters, depending on your ideology. There's no point sending an aircraft carrier against an anonymous guy in a hotel room. A couple of police officers will do... IF you know where to send them.

It doesn't seem to me that fighting to win with the lmited resources you have at your disposal implies a lack of guts or honour.