By Ann Roosevelt
For the first time, a solid-state laser (SSL) has reached weapons grade power of interest to the Army as a Northrop Grumman [NOC] laser produced more than 100 kilowatts (kW) in a lab.
“It’s a culminating achievement for the solid state laser program,” Dan Wildt, vice president of Directed Energy Systems for Northrop Grumman’s Aerospace Systems sector, said in a teleconference yesterday.
“We’re doing our part to make gunpowder a 20th century technology,” he said.
A Joint SSL Science & Technology effort executed by the Army Space and Missile Defense Command/Army Forces Strategic Command, the Northrop Grumman laser is one of two lasers being developed in cooperation with the High Energy Laser Joint Technology Office and other services.
The second device, under development by Textron [TXT], also is expected to achieve 100 kW performance this year.
As a weapon, a 100kW laser can rapidly heat a target causing catastrophic effects such as exploding a warhead or airframe failure.
Northrop Grumman uses a scaled building block approach for the compact, electric laser weapons.
Wildt said with scaled building blocks, the SSL is designed to be a plug and play unit–if you imagine a file cabinet play unit, this [the building block] is a drawer in a file cabinet…If you understand a mission, you develop the right cabinet and put in the right number of units.”
The record SSL 100kW first came as the company completed the final demonstration milestone of the Joint High Power Solid State Laser (JHPSSL) program Phase 3.
The achievements included a turn-on time of less than one second and continuous operating time of five minutes, with very good efficiency and beam quality.
Last year, Northrop Grumman reported reaching a JHPSSL Phase 3 power level of 15.3kW in March and a power level of 30kW in September.
“Our modular JHPSSL design makes it straightforward to scale laser weapon systems to mission-required power levels for a variety of uses, to include force protection and precision strike missions for air-, sea- and land based platforms,” Wildt said in a statement.
“This achievement is particularly important because the 100kW threshold has been viewed traditionally as a proof of principle for weapons grade’ power levels for high-energy lasers. In fact, many militarily useful effects can be achieved by laser weapons of 25kW or 50 kW, provided this energy is transmitted with good beam quality, as our system does. With this milestone, we have far exceeded those needs.”
Wildt said, “Power scaling will be one of the game-changing features of high-energy lasers because it allows graduated responses by U.S. military services appropriate for whatever level of threat they may face. Threats vary, and so should the response.”
Jay Marmo, Northrop Grumman’s JHPSSL program manager, said the company’s scalable, building block approach also readily enables more challenging missions that require well above 100 kW of good beam quality laser power.
“Getting to 100 kW with replicated building blocks proves we can scale to these higher power levels if required for a given mission. This watershed development, coupled with our FIRESTRIKE(tm) laser ruggedization work, unequivocally demonstrates that Northrop Grumman is ready to bring high-power, solid state lasers to the defense of our deployed forces.”
Using its own funds, Northrop Grumman built the FIRESTRIKE, looking at some of the issues that must be addressed to reach a SSL laser weapon.
For building blocks, the company utilizes “laser amplifier chains,” each producing approximately 15kW of power in a high-quality beam. Seven laser chains were combined to produce a single beam of 105.5 kW. The seven-chain JHPSSL laser demonstrator ran for more than five minutes, achieved electro-optical efficiency of 19.3 percent, reaching full power in less than 0.6 seconds, all with beam quality of better than 3.0.
The laser already has been operated at above 100kW for a total duration of more than 85 minutes. A government team reviewed results of the demonstration during a System Test Data Review held Feb. 10 at Northrop Grumman’s Directed Energy Production Facility in Redondo Beach, Calif.
“It is notable that we were able to meet the power demonstration goal with only seven laser chains, rather than the full eight chains we can accommodate. This shows the robustness of our industry-unique approach and the ability of our lasers to deliver predicted performance,” Marmo said. “Adding the eighth chain will increase laser power to 120kW.”
The company received a 36-month, $56 million contract for JHPSSL Phase 3 in December 2005, when the Army decided to focus on all-electric SSLs as a lower-cost high-energy laser.
Over the past six years, Northrop Grumman received a total of slightly over $98 million for all three phases of work.
The JHPSSL program is funded by the Office of the Assistant Secretary of the Army for Acquisition, Logistics, and Technology; Office of the Secretary of Defense-High Energy Laser Joint Technology Office, Albuquerque, N.M.; Air Force Research Laboratory, Kirtland AFB, N.M.; and the Office of Naval Research, Arlington, Va.
Responsibility for program execution is assigned to the Army Space and Missile Defense Command/Army Forces Strategic Command in Huntsville, Ala.