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Posts Tagged ‘laser weapons’

Yesterday, the two defense contractors announced that they are jointly developing a demonstration model Mk 38 with dual capabilities. The chain gun--originally designed to be manually aimed and fired--will now be remote-controlled and use an electro-optical/IR sensor ball to detect and track incoming targets, like UAVs or small watercraft (like the one that perpetrated the attack on the USS Cole in Yemen several years ago).

But according to a BAE-Boeing announcement, “the system also provides the ability to deliver different levels of laser energy, depending on the target and mission objectives.” Danger Room tells us that the fiber laser system can pack up to 10 kilowatts of punch, far below what the U.S. military has previously considered weapons grade but nonetheless effective--just a few months ago an Office of Naval Research laser fried the engine of a small watercraft with a 15 kilowatt beam (though that was designed to be scaled up to a more impressive 100 kilowatts).

Presumably, the Mk 38’s laser package could be upgraded as well, making the death ray part of the system quite a bit deadlier. Which is good, considering that sea air--rife with moisture and particulate stuff that degrades focused laser beams--compounds the many problems inherent in laser weapons systems.

[Defense Tech, Danger Room]

TeraDiode’s system is based on semiconductor laser technology (fueled by electricity rather than chemicals, which is already a plus from a safe-handling standpoint) augmented by an optical system that wrangles several beams of light into a single powerful beam. Powerful enough, the company says, for industrial cutting and welding. Or for blowing stuff up.

Weapons-grade lasers are a tough sell (as regular PopSci readers know from our ongoing boomand bust coverage of the Missile Defense Agency’s Airborne Laser Test Bed), but if TeraDiode’s system can pack as much punch into a small package as the company claims, it could be onto something.

The company sees its lasers someday deployed on ships or tanks, small enough to be mobile but strong enough to down a UAV or perhaps even knock incoming artillery or RPGs out of the air. More near term, it wants to get its direct-diodes on the back of fighter jets to confuse--or perhaps even destroy--incoming anti-aircraft missiles. And TeraDiode isn’t just talking a big game it seems--the company told Xconomy that testing on the aircraft defense system could begin in a year, with deployment in three to five years.

[Xconomy]

Development of the FEL program has been a large undertaking for the Navy, which has invested at least $163 million in a new kind of variable-wavelength laser weapon that should be effective at sea, where moisture and aerosols in the air can severely limit the effectiveness at lasers at certain wavelengths.

The FEL itself isn’t new—it was invented decades ago—but fielding a high energy beam is something else entirely. All lasers need some kind of medium—solid state lasers use crystals, chemical lasers use chemicals—to generate the intense light that is then focused into a laser beam. That lasing medium pretty firmly predetermines the wavelength of a laser beam.

The FEL works differently, using magnetic fields to focus a stream of supercharged electrons into powerful beams at varying wavelengths, making it more versatile. But in order to create a free electron laser weapon, researchers at ONR had to design an injector capable of feeding enough electrons into the system to sustain a weapons-grade beam, ideally something in the megawatt class.

Doing so represents a major milestone for the program, putting a ship-based FEL weapons system within reach. Researchers are now studying their continuous electron beams made possible by their new injector and aiming to set a world record for the average current of electrons. That represents a huge step forward from the 14-kilowatt prototype the ONR team started with. The Navy hopes to have a testable prototype by 2018.

FYI, more on the FEL via the ONR below.

[ONR]

But don't worry, it will still be partly a death ray

Such a multipurpose tool certainly makes the Navy’s laser system seem a more practical use of funding, and a free electron laser is the proper tool for the job(s). All lasers require some kind of medium to turn light into high-energy beams--solid state lasers use crystals, while chemical lasers use (you guessed it) a stew of unfriendly chemicals. Both of those versions have their pros and cons, but neither is extraordinarily versatile; they generally power their lasers up to a certain wavelength and that’s that.

Free electron lasers, on the other hand, use a stream of supercharged electrons to power the laser at varying wavelengths. This versatility is why the Navy has referred to FELs as the Holy Grail of laser tech and why it has embarked on a $163 million quest to develop a working weapons system, $26 million of which is currently facilitating a development program at Boeing that’s due for delivery in 2012.

The ability to shift wavelengths means that unlike other lasers--including the solid-state bad boy Raytheon used to knock a UAV out of the air from the deck of a ship earlier this year--an FEL system can adjust that wavelength for a variety of tasks. Further, it could run off a vessel’s power source rather than requiring its own, so it wouldn’t need to stop and reload.

That’s why, according to Danger Room's Spencer Ackerman (who is reporting from the Office of Naval Research’s science and tech conference this week), naval program managers are excited about their FEL. Those myriad uses for the platform would require much less energy than is required for actually knocking cruise missiles out of the sky, reducing the platform’s energy energy needs.

Of course, the Navy still wants its laser to target and destroy incoming threats, and therein lies the challenge. The lower power threshold for a weaponized laser of this nature is more or less 100 kilowatts; the FEL at the DOE lab where the Navy has been sponsoring research currently runs at about 14 kilowatts. Boeing’s job is to make up the difference so the Navy’s FEL can perform tasks that require 50 watts, 100-plus kilowatts, and everything in between.

Difficult, but certainly not impossible. There’s more background on the ONR’s efforts to this point in the video below.

[Danger Room]

Lockheed Martin has a solution: a fiber laser that basically works like a backward prism.

Lockheed is among three firms recently awarded contracts to develop a laser for the military’s Robust Electric Laser Initiative, which seeks to improve the power of electric lasers. Fiber lasers are efficient and compact, but until now they have been weaker than other types, like chemical lasers. The RELI program seeks to improve laser strength while reducing power and cooling, so systems can be small enough to install on ships or airplanes.

A Lockheed subsidiary developed a first-of-its-kind high-powered fiber laser capable of producing 100 kilowatts or more, according to Lockheed. It uses fiber optics to produce near-perfect beams. The method also confines the laser light to the fiber’s glass structure without using mirrors or other optics.

John Wojnar, director of business development for the laser systems business, said in a September issue of Aviation Week that it works like a inverse prism: lasers with slightly different wavelengths enter a combiner, and the result is a single, focused beam. It’s called Spectral Beam Combining.

Lockheed won an initial $14 million contract from the US Army Space and Missile Defense Command to develop the system. Along with General Atomics and Raytheon, the firm must demonstrate a 25 kW system that can be scaled up to 100 kW within five years.

General Atomics will improve its Hellads distributed-gain laser approach to improve efficiency, while Raytheon will pursue a planar waveguide laser, according to Aviation Week.

Northrop Grumman is also expected to obtain a RELI contract.

The tests, conducted in May and June, show the LaWS illuminating and then heating the underside of a drone aircraft shortly before it goes up in flames and loses trajectory, plummeting into the ocean below. Guided by Raytheon's Laser Close-in Weapon System (CIWS), a sensor suite that locks onto and guides the energy weapon, LaWS shot down three similar drones during the tests, which mark the first time a solid-state laser has shot down an aircraft on the wing over open seas.

There are three significant parts to this story. First, it's important to note that LaWS is a solid-state laser rather than a chemical laser, which means it's not quite so hazardous to handle and requires less energy to use. It's also smaller, which makes it a lot more feasible to pack onto a naval vessel. Second, solid-state lasers are generally weaker than chemical lasers, and that problem is compounded by the moist air in ocean climates, as that moisture can absorb laser energy and weaken the beam. So proving this solid-state technology can work at sufficient strengths over the ocean is a serious milestone.

But most importantly, Raytheon demonstrated that a laser integrated into the Navy's Phalanx anti-missile defense system -- a weapons system already mounted on many naval vessels -- can hit a moving target from the deck of a ship, which itself is moving and rolling along with the ocean. That's pretty sharp shooting, and it could arm U.S. seamen with a greatly enhanced last line of defense during aerial and ballistic missile warfare at sea.

Of course, what works on a moving naval platform also works from stationary, land-based positions, and Raytheon is also looking to mount the system on trailers much as Boeing has done with its Mobile Active Targeting Resource for Integrated experiments (MATRIX). That system, along with some of Boeing's other directed energy systems, shot down several UAVs last year. But if Raytheon can do it in a smaller, less energy-intensive package the military might find that more compact solid-state lasers are the future.

Check out the CIWS roasting a drone below.

[Raytheon via BBC]

There are few details available about the highly classified technology, about which the Pentagon is remaining silent. USA Today describes it as a beam which “bypasses the triggering device of an IED and detonates its explosive.” As such, it can not only be used to detonate explosives on the ground, but explosives that are still being built and transported by insurgents.

While the idea of leveraging technology to give insurgents a taste of their own medicine may sound attractive to military on the ground, it also opens the door to potential problems, namely the collateral damage caused when an unexpected explosion of indeterminate magnitude is triggered in the middle of a street. It’s easy to see how such incidents could quickly get crosswise with Gen. Stanley McChrystal’s mandate to reduce civilian casualties in Afghanistan.

Which brings military researchers to yet another problem – the countermeasure is reportedly huge, big enough in fact that a tractor trailer is needed to haul the thing around. It’s allegedly been tested at checkpoints in Iraq in both 2005 and 2008, but it’s highly cumbersome for mobile, outside-the-wire operations. In rugged terrain like that of Afghanistan, this presents a major logistical problem.

One U.S. Joint Forces Command official has suggested using the device from airborne platforms that could clear roadways ahead of convoys. In the meantime the Office of Naval Research, which developed the device, is looking to create a smaller, more mobile IED hunter.

[USA Today]