美海軍將部署激光武器 準備海上“星球大戰”

Some of the Navy's futuristic weapons sound like something out of "Star Wars," with lasers designed to shoot down aerial drones and electric guns that fire projectiles at hypersonic speeds.

That future is now.

The Navy plans to deploy its first laser on a ship later this year, and it intends to test an electromagnetic rail gun prototype aboard a vessel within two years.

For the Navy, it's not so much about the whiz-bang technology as it is about the economics of such armaments. Both costs pennies on the dollar compared with missiles and smart bombs, and the weapons can be fired continuously, unlike missiles and bombs, which eventually run out.

"It fundamentally changes the way we fight," said Capt. Mike Ziv, program manager for directed energy and electric weapon systems for the Naval Sea Systems Command.

The Navy's laser technology has evolved to the point that a prototype to be deployed aboard the USS Ponce this summer can be operated by a single sailor, he said.

The solid-state Laser Weapon System is designed to target what the Navy describes as "asymmetrical threats." Those include aerial drones, speed boats and swarm boats, all potential threats to warships in the Persian Gulf, where the Ponce, a floating staging base, is set to be deployed.

Rail guns, which have been tested on land in Virginia, fire a projectile at six or seven times the speed of sound — enough velocity to cause severe damage. The Navy sees them as replacing or supplementing old-school guns, firing lethal projectiles from long distances.

But both systems have shortcomings.

Lasers tend to loser their effectiveness if it's raining, if it's dusty, or if there's turbulence in the atmosphere, and the rail gun requires vast amount of electricity to launch the projectile, said Loren Thompson, defense analyst at the Lexington Institute.

"The Navy says it's found ways to deal with use of lasers in bad weather, but there's little doubt that the range of the weapon would be reduced by clouds, dust or precipitation," he said.

Producing enough energy for a rail gun is another problem.

The Navy's new destroyer, the Zumwalt, under construction at Bath Iron Works in Maine, is the only ship with enough electric power to run a rail gun. The stealthy ship's gas turbine-powered generators can produce up to 78 megawatts of power. That's enough electricity for a medium-size city — and more than enough for a rail gun.

Technology from the three ships in that DDG-1000 series will likely trickle down into future warships, said Capt. James Downey, the program manager.

Engineers are also working on a battery system to store enough energy to allow a rail gun to be operated on warships currently in the fleet.

Both weapon systems are prized because they serve to "get ahead of the cost curve," Ziv said.

In other words, they're cheap.

Each interceptor missile aboard a U.S. Navy warship costs at least $1 million apiece, making it cost-prohibitive to defend a ship in some hostile environments in which an enemy is using aircraft, drones, artillery, cruise missiles and artillery, Thompson said.

With a laser operating on about 30 kilowatts of electricity — and possibly three times that in the future — the cost amounts to a few dollars per shot, Thompson said.

The "Star Wars" analogy isn't a bad one.

Just like in the movies, the Navy's laser directs a beam of energy that can burn through a target or fry sensitive electronics. Unlike the movie, the laser beam is invisible to the human eye.

The targeting system locks onto the target, sending a beam of searing heat. "You see the effect on what you are targeting but you don't see the actual beam," Ziv said.

Other nations are developing their own lasers, but the Navy is more advanced at this point.

Most folks are stunned to learn the technology is ready for deployment, Ziv said.

"It's fair to say that there are other countries working on this technology. That's safe to say. But I would also say that a lot of what makes this successful came from the way in which we consolidated all of the complexity into something that can be operated by (a single sailor)," he said.據美國媒體2月17日報道，美國海軍打算2013年夏天首次在軍艦上部署激光炮，並於2年之內對磁軌炮進行初步測試。這些未來範十足的裝備頗有電影《星球大戰》的風格。

***電磁武器

美國海軍計劃夏天在“龐塞”號軍艦上部署激光炮。雖然只是原型機，其操作已經非常簡單，一名士兵就能勝任。“龐塞”號曾是一艘運輸船，近年來被改裝成高科技浮動基地，主要在波斯灣區保護軍艦，應對無人機、快艇等“不對稱威脅”。

美國還在弗吉尼亞州試發過磁軌炮，發射速度相當於6到7倍音速，頗有威力。美國海軍打算用它們補充，甚至取代傳統大炮。

***兩大侷限

美軍開發新式武器主要是爲了壓縮成本，不是追求炫酷的科技。和傳統武器相比，電磁武器有兩大優勢。首先它們價格低廉；其次不必擔心彈藥儲備，能夠持續發射。國防專家洛倫•湯普森表示，美國軍艦上配備的攔截導彈每一枚耗資至少100萬美元（約合606萬元人民幣），價格昂貴。不過，耗能30千瓦的磁軌炮每發一次只需要幾塊錢。美國海軍海上系統司令部旗下電子武器系統項目主管麥克•齊夫認爲，新型電磁武器將從根本上改變人們的作戰方式。

電磁武器也有兩大侷限，它們易受天氣影響，並且能耗較高。天氣方面，湯普森說：“毫無疑問，雲霧、灰塵和降雨會使武器的射程縮短。海軍說已經找到了應對方法。”在能量方面，美國只有在建的“朱姆沃爾特”號驅逐艦擁有足夠能量滿足新型武器。“朱姆沃爾特”號最高能產生78兆瓦電力，相當於一座中型城市的發電水平，發射電磁炮綽綽有餘。美軍軍官表示，以“朱姆沃爾特”號爲首的3艘“朱姆沃爾特”級軍艦都將配備新式武器。而工程師也正在改進電池系統，方便軍艦發射電磁炮。

海軍電磁武器不由得讓人想起電影《星球大戰》中的激光劍，二者都是破壞力十足的一道光。不同的是，我們用肉眼看得到電影裏的劍，卻看不到軍艦上打出的電子“炮彈”。電磁武器瞄準目標發出一道高能光束。齊夫說：“你看得見擊中目標的效果，卻看不見那一道光。”