Airborne Laser fires high-energy light through beam-steering system
The megawatt-class Airborne Laser (ABL) weapon system, a chemical oxygen iodine laser (COIL) mounted in a modified Boeing 747 aircraft, can now fire its beam through its beam-steering system and out the nose of the aircraft.
Last week, in a ground test at Edwards Air Force Base in California, the U.S. Missile Defense Agency (MDA) and an industry team led by prime contractor Boeing (Seattle, WA) fired the high-energy laser through the entire system for the first time. The beam then exited the aircraft and was captured by the Range Simulator Diagnostic System, which provides simulated targets as well as a "dump" and diagnostics for the laser beam. (In September of this year, the high-energy beam was fired within the aircraft in a ground test, but the beam did not pass through the beam-steering system. Instead, it was dumped into an onboard calorimeter.)
The COIL was developed by Northrop Grumman Corporation (Redondo Beach, CA); the beam-steering system, termed the Beam Control/Fire Control (BC/FC) system, was developed by Lockheed Martin Space Systems Company (Sunnyvale, CA).
Michael Rinn, Boeing vice president and ABL program director, said the next step for the program is a series of longer-duration laser firings through the beam control/fire control system. The ground tests will be followed by flight testing of the entire ABL system that will culminate in an airborne intercept test against a ballistic missile in 2009.
The ABL aircraft consists of a modified Boeing 747-400F whose back half holds the high-energy laser. Before being installed, the high-energy laser completed rigorous ground testing in a laboratory at Edwards AFB. The front half of the aircraft contains the battle management system, provided by Boeing, and the BC/FC system.
In addition to aiming the laser beam, the BC/FC system performs fire-control engagement sequencing, adjusts the beam for atmospheric compensation, and helps control jitter. Without compensation for atmospheric turbulence, the laser beam would illuminate the target as a large, randomly varying pattern of light; with compensation, it strikes the target in one small high-intensity spot.
The BC/FC system's lower-energy lasers--the Track Illuminator Laser and the Beacon Illuminator Laser--determine where to point and focus the high-energy COIL beam. The high-energy beam passes through the system's optical path before exiting through the conformal window on the nose of the aircraft on its way to the target. Flight testing in 2007, using a surrogate high-energy laser, verified the ability of the BC/FC system to maintain the focus of the laser beam while continuously tracking a target.
The ABL will destroy a ballistic missile during its boost phase, while it is still accelerating in the Earth's atmosphere and before it can deploy its warheads. The Missile Defense Agency manages the ABL program, which is executed by the U.S. Air Force from Kirtland Air Force Base (Albuquerque, NM).

John Wallace | Senior Technical Editor (1998-2022)
John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.