WASHINGTON — Northrop Grumman Space Technology of Redondo Beach, Calif., expects by the end of 2008 to demonstrate a solid-state laser in the 100-kilowatt class, powerful enough for military applications such as destroying cruise missiles, aircraft and unmanned aerial vehicles (UAVs), the company announced March 11.
Solid-state lasers are smaller but far less powerful than the megawatt-class chemical lasers that have been in testing since the 1980s. Chemical lasers require vast amounts of space to house their extensive subsystems and plumbing; the Chemical Oxygen Iodine Laser, built by Northrop Grumman for the U.S. Missile Defense Agency’s Airborne Laser program, for example, is being fitted aboard a modified Boeing 747 jumbo jet.
Solid-state lasers, by contrast, could be placed on platforms like fighter jets or UAVs. Their limitation has always been power; at the turn of the century, state- of-the-art solid-state lasers were capable of around 5 kilowatts, only enough to take out soft targets like sensors, or perhaps landmines and radars in long-duration firings.
Since 2002 Northrop Grumman has been working through the first three phases of the Joint High-Powered Solid State Laser (JHPSSL) program for the U.S. Army Space and Missile Defense Command. In the first phase, Northrop Grumman addressed risk reduction issues associated with generating high power and beam quality in a solid-state laser. During phase 2, awarded in 2002, Northrop Grumman scaled the technology up to 25 kilowatts. That was followed in December 2005 by a three-year, $56.7 million contract for the third phase of the program.
Textron Systems of Wilmington, Mass., also was awarded a contract for the program at that time valued at $10 million with options that could increase its value to $30 million, according to a Textron press release. A Textron spokeswoman said the company could not comment on the status of their work without approval from the program office, which was not given as of press time.
Speaking at a March 11 media event here, Dan Wildt, Northrop Grumman’s vice president for directed energy systems, said shrinking the technology to a manageable size has been a priority under the current phase of the program.
The 25-kilowatt laser Northrop Grumman previously demonstrated was built on a platform about 4.6 meters long. To get to 100 kilowatts in this phase, company engineers will have to combine eight 15-kilowatt laser chains of four modules each. Each laser chain will be built onto a square platform measuring about 102 centimeters on a side. When assembled, the laser chains will fit onto a 223 by 279 centimeter platform.
The company in December demonstrated the ability to simultaneously operate the four modules of a laser chain and manipulate the beams to generate an aggregate power of 15.3 kilowatts for more than 300 seconds, exceeding both the power and time requirements of the contract, Wildt said.
With this milestone now under his belt, Wildt said he is confident the company will reach the 100-kilowatt mark by the end of 2008.
“Having the successful demonstration of a complete laser chain—the building block of the fully integrated laser—the hardest part is over,” he said.
While there are many potential defense applications for solid- state lasers, missions like shooting down ICBMs are still well out of reach for this technology. But Northrop Grumman believes that with enough development funding, megawatt-class solid state lasers would be feasible in three to 10 years. Wildt said solid- state lasers eventually could overtake chemical lasers in power- generating capability and replace them in some instances.
“There are physics issues you have to overcome,” he said. “You need to get more power per unit of volume out of your battery. While a 100-kilowatt solid state laser is smaller than a chemical one [of identical power], it’s not clear as you scale to the megawatt class which of the two will be the most attractive. If you project out to 2050, technologies can come a long way and I can see solid state lasers replacing chemical lasers, but I can’t see it for the near term.”