Small step toward Star Wars - DARPA pushes forward with aircraft-based lasers

Small step toward Star Wars - DARPA pushes forward with aircraft-based lasers

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News & Events - Engineering News

January 25, 2013

The White House may have shot down the petition for the U.S. to build it's own Death Star, but science fiction fans can take heart - the Defense Advanced Research Projects Agency is still in their corner. While planet-annihilating space stations may be out of the picture, the X-Wings that took them down might be coming a step closer as the Department of Defense's research arm is pushing forward with a project to test aircraft-based lasers, according to Aviation Week.

Unlike the iconic starfighter, this particular laser is not meant to be used as an offensive weapon, but rather would serve as a defensive system protecting aircraft from incoming surface-to-air missiles and rockets.

The idea is for the laser to be to swivel around to target missiles as they are detected and quickly overheat them to the point of structural failure. The advantage of these systems compared to chaff, ejected material designed to confuse targeting systems, and other mechanical approaches is that lasers can be targeted extremely precisely, providing greater certainty that the missile will be disabled.

Just as importantly, it is effectively impossible for targets to avoid laser strikes, since the attack occurs at the speed of light.

Overcoming limitations
Unfortunately, to this point, laser systems have largely not met the desired weight to power ratio of five kilograms per kilowatt, an important consideration for aircraft traveling large distances on limited fuel. But intensive engineering research and development by General Atomics Aeronautics Systems has resulted in the creation of an effective 34-kilowatt model that meets that crucial design goal.

One expert told Fast Company that older laser systems could be as large as a passenger jet, and so were impractical for use in flight.

However, it turns out that one of the biggest limiting factors was actually the inability of these laser systems to accurately compensate for turbulence in the air behind the fast-moving jets. General Atomics' new design uses advanced optics and and other engineering advances to work past this limitation, giving it the ability to attack targets coming from any direction.

Testing the next generation
Known as HELLADS - High Energy Liquid Laser Area Defense System - this system combines the advantages of high-powered solid-state lasers with the continuous firing capability of liquid-cooled lasers, making them significantly more effective and weight efficient than either traditional approaches.

More importantly, each of the critical components has already been tested and relatively well-proven at this point, only requiring engineers to put all the pieces together for a full-scale trial.

General Atomics was scheduled to put together a larger 150-kilowatt laser - large enough, the Air Force estimates, to take down surface-based missiles - by the end of last year. These components will all need to be proven once again, with in-flight tests planned for sometime next year.

Growing field
Lasers are seeing increasing use in military applications around the world. In addition to HELLADS, the U.S. had also been working with the Israeli government to develop the Nautilus Tactical High Energy Laser, a ground-based defensive system designed to prevent rocket attacks, until it backed out of the project in 2006. Israel eventually rolled out a working model of the system, but it has yet to see widespread implementation.

In the meantime, countries from Russia to India have also begun research in laser defense, while HELLADS could prove powerful enough to provide a defense against even larger systems like unmanned drones. And, of course, high-energy batteries are also an increasing area of engineering research with the rising prominence of intermittent renewable energy sources, leading to advances that could easily be applied to military-grade lasers.

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