A laser set to begin live-fire tests at White Sands Missile Range, New Mexico, in January uses rare earth minerals. It was developed by General Atomics Aeronautical Systems Inc. of Poway, Calif., the company that produced the revolutionary MQ-1 Predator drone. Its precise power levels are classified, but Michael Perry, the company’s vice president for laser programs, said the experimental weapon’s beam is in the 150-kilowatt class. That’s more than 100 times the power needed to heat an electric oven to 350 degrees.
The General Atomics laser is five times more powerful than the only laser the military has fielded, the 30-kilowatt-class Laser Weapon System, a fiber laser the Navy developed that has knocked down small drones and crippled small boat swarms in tests at short range. That laser was installed on the USS Ponce, an Afloat Forward Staging Base deployed to the Middle East, in 2014. This past October, the Navy awarded Northrop Grumman a $53 million contract to develop a more powerful shipboard laser.
Bulk lasers use slabs or strips of rare earth minerals — ytterbium, for example — as their gain medium. Fiber lasers “gang” fiber-optic cables together as the gain medium.
A General Atomics rendering shows a laser weapon fired from the company’s new jet-powered Predator C Avenger drone (though in real life, the laser is invisible). Photo: General Atomics
The General Atomics laser is to be tested at White Sands for 18 months or more by the Defense Advanced Research Projects Agency and the Air Force Research Laboratory. The testers will fire live laser shots at a broad range of airborne targets, including rockets, artillery, mortars, cruise missiles and surface-to-air missiles.
The laser’s design was frozen in 2011, and the system is far too large to fit in an aircraft. But General Atomics has developed another version that fits in a box 12 feet long, 4 feet wide and 2 feet tall.
General Atomics is also working on a configuration specifically designed for the AC-130 plane and another for its jet-powered Predator C Avenger drone.
Lt. Gen. Bradley Heithold, commander of Air Force Special Operations Command, said a number of other companies are also working on lasers that might be suitable for use on the AC-130. Lockheed Martin, the aircraft’s manufacturer, is developing a 60-kilowatt-class laser for the Army, for example, and Northrop has advertised its interest in developing airborne lasers as well. AFSOC has studies under way to determine the best solution.
The possible targets for an AC-130 laser are many, Heithold said. The silent, invisible beam might be used prior to a hostage rescue mission, for example, to covertly disable motor vehicles, boats, airplanes or any other “escape mechanism” an enemy might use to move the hostages or flee from U.S. forces. The laser might also be used to disable or disrupt an enemy’s communications, he said.
In three years the US military could have a prototype 300 kilowatt laser weapon. This would be ten times the power of the 30 kilowatt laser being tested on the USS Ponce. Sydney J. Freedberg Jr. of Breaking Defense reports this from a Lockheed engineer.
The Army’s High Energy Laser Mobile Demonstrator(HEL MD) will improve to a 60 kw system late in 2016. This is up from the current 10 kilowatt laser. Today’s technology will enable fiber lasers to scale to 300 kw. Near term improvement to the underlying technology will enable well beyond 500 kw lasers.
Solid state slab lasers (being developed by the Navy and Northrop) should be able to scale to a total power of 300 kW. This will not require any technological breakthroughs. Supporters of slab SSLs such as Maritime Laser Demonstration (MLD) believe they could eventually be scaled up further, to perhaps 600 kW. Slab SSLs are not generally viewed as easily scalable to megawatt power levels.
At 30 to 35 percent efficiency — the current cutting edge with fiber-optic lasers — 300 kw of output would require just under a megawatt of electrical power.
The Navy’s LaWs simply sticks together six commercial cutting lasers and points them all at the same target. Lockheed’s technology goes further and combines all the lasers into a single, coherent beam, which allows much sharper focus at long ranges.