Northrop-Grumman, leading manufacturer of combat lasers, believes these weapons are only a few years away from battlefield use. To that end, the company has set up a new divisions to develop and build the battle lasers. This optimism was caused by two successful tests last year. In one, a solid state laser shot down a mortar round. In another, a much more powerful chemical laser, firing from a customized B-747, hit a missile type target. 

Solid state lasers have been around since the 1950s, and chemical lasers first appeared in the 1970s. The chemical laser has the advantage of using a chemical reaction to create the megawatt level of energy for a laser that can penetrate the body of a ballistic missile that is still rising in the air hundreds of kilometers away. The chemical reaction uses atomized liquid hydrogen peroxide and potassium hydroxide and chlorine gas to form an ionized form of oxygen known as singlet delta oxygen (SDO).) This, in turn is rapidly mixed with molecular iodine gas to form ionized iodine gas. At that point, the ionized iodine gas rapidly returns to its resting state, and while doing so releases photons pulsing at the right frequency to create the laser light. These photons are channeled by mirrors and sent on their way to the target (which is being tracked and pinpointed by other lasers). The airborne laser actually consists of six identical units, each weighing 2.3 tons and about the size of a large SUV. The six modules are hooked up in series within the B-747, producing a laser powerful enough to do the job. The laser exist via a targeting turret in the nose of the aircraft. The laser beam is invisible to the human eye.  The chemicals are mixed at high speeds, and the byproducts are harmless heat, potassium salt, water, and oxygen. But the airborne laser, flying in an aircraft weighing 400 tons. 

Nearly half a century of engineering work has produced thousands of improvements, and a few breakthroughs, in making the lasers more powerful, accurate and lethal. More efficient energy storage has made it possible to use lighter, shorter range ground based lasers effective against smaller targets like mortar shells and short-range rockets. Northrops move is an indication that the company feels confident enough to gamble its own money, instead of what they get for government research contracts, to produce useful laser weapons. The high energy airborne laser would not only be useful against ballistic missiles. Enemy aircraft and space satellites would also be at risk.