Air Borne Lasers

[buglerbilly]

Ares

A Defense Technology Blog

ABL Range Grows ... So Now What?

Posted by Amy Butler at 6/21/2010 10:29 AM CDT

Aviation Week's International Editor Robert Wall filed this story (below) today during the pre-Farnborough Boeing media trip. Thought our Ares readers would be interested.

It's a noble goal for the company to expand the Airborne Laser's range ... but I wonder about where this technology is going and if it has a future in a DoD recently enamored with the promise of solid-state lasers.


February ABL shootdown exercise. source: US MDA

Here's what Wall filed ...

The Boeing 747-400-based Airborne Laser Test Bed is now firing its high-power chemical laser at three to four times the range seen in the original shoot down, according to Boeing.
The test bed is flying about twice a month with the laser firing once a month against a target board or against actual targets, says Roger Krone, president of Boeing Network & Space Systems. Several firings have taken place since the first shootdown in February and further shots this year are planned. Much of the focus has been on expanding the envelope of the laser system, not just in range but also engagement angles, Krone notes.

One of the criticisms within the Pentagon against ABL has been its perceived limited range and the need to position the 747 close to a threat. But Krone says “it is our hope that over the next year that we will demonstrate the utility of the total system”.

The test bed funding will continue into next year. The Missile Defense Agency (MDA) in the coming weeks should be defining what activities are planned for that period, says Mira Ricardel, the company’s vice president business development for Strategic Missile & Defense Systems. That could also involve different missions.

Krone says Boeing has had discussions with MDA about potentially hosting a solid-state laser on the test bed as well and using the existing optics. The 747 would have the room to accommodate the solid state laser aside the current COIL laser.

Also, the U.S. Navy next month is expected to make a downselect between Raytheon and Boeing for the free electron laser program. The next phase would last around 15 months to see the system through to critical design review. Phase two would follow and lead to a 100kW laser demonstration, with at-sea trials planned for phase three.

[buglerbilly]

Ares

A Defense Technology Blog

DARPA's RIFL Points Way to Combat Lasers

Posted by Graham Warwick at 6/23/2010 12:59 PM CDT

Directed energy weapons are getting a lot of attention as people start thinking about next-generation platforms. Solid-state electric lasers are showing promise, as defensive and offensive weapons, but there is a way to go before they will be compact and efficient enough to fit in a combat aircraft.

Now Northrop Grumman has achieved a milestone in development of a high-energy laser that promises to be smaller and lighter. The company has demonstrated a 1kW fiber laser amplifier with a beam quality high enough to optically combine the output from several laser chains to achieve high power. The company will now proceed to the next phase with the goal of demonstrating a 3kW fiber laser.


Photo: Northrop Grumman

Northrop was first to demonstrate lethal power levels exceeding 100kW with an electric laser under the DoD's Joint High Power Solid-State Laser program. This optically combined the beams from chains of diode-pumped slab lasers. The problem with this type of laser, for aircraft, is how inefficiently it turns electricity into light. For a 100kW laser beam, an electro-optical efficiency of 15% means generating 600kW of power and getting rid of a lot of heat.

The fiber laser promises efficiencies of 30%, if the individual fiber amplifiers can be scaled up in power and their beams combined. In Phase 1 of DARPA's Revolution in Fiber Lasers (RIFL) program, Northrop says it achieved 1kW with an efficiency better than 30% (twice the Phase 1 goal) and a beam quality better than 1.2 (1.0 is the ideal). In Phase 2 the company will try to maintain that efficiency and beam quality while scaling the fiber laser to 3kW.

The ultimate goal is a 100kW laser weapon system weighing less than 5kg per kilowatt of laser power. This also happens to be the weight metric for DARPA's Hellads program, which is developing a 150kW slab-laser weapon system for flight testing in the weapons bay of a B-1. General Atomics and Textron Defense Systems are developing competing Hellads lasers. Ground tests are planned for 2012, and the Air Force Research Laboratory plans to fly the Hellads in a B-1 under its Electric Laser on a Large Aircraft (ELLA) program.