1/19/2007 - EDWARDS AIR FORCE BASE, CA. -- YAL-1A, a modified Boeing 747-400F known as the Airborne Laser, made its return journey to the Air Force Flight Test Center in December after undergoing modifications at Boeing's facilities in Wichita, Kan.

The modifications on the aircraft include the installation of the beam control and fire control solid-state illuminators, as well as the addition of floor reinforcements and chemical-fuel tanks. These modifications were necessary for the integration, later this year, of the Chemical Oxygen Iodine Laser, or COIL -- a missile-killing, high-energy chemical laser.

The COIL is composed of six interconnected modules, each as large as a sport utility vehicle turned on end. Each module weighs about 6,500 pounds and has 3,600 separate parts. When fired through a window in the aircraft's nose turret, it produces enough energy in a five-second burst to power a typical household for more than one hour.

The Missile Defense Agency is testing and developing the ABL as part of the boost phase defense segment of the Ballistic Missile Defense System.

The ABL, designed to identify, track and intercept enemy ballistic missiles shortly after missile launch, would operate at altitudes above the clouds to locate and track missiles in their boost flight phase, and then accurately point and fire the high-energy laser to intercept enemy missiles near their launch areas, MDA officials said.

"Many modifications and improvements have been conducted at the Birk Flight Test Facility, here, to maintain this 'one-of-a-kind' weapons system," said Troy Gabbard, ABL Site and Facilities Support director here.

Since its return in December, the aircraft began a long-term test phase that includes the test firing of the aircraft's low-power lasers in flight for the first time.
During these tests, which will happen over the next several months, the ABL will fire its two solid-state illuminator lasers at the NC-135E "Big Crow" test aircraft to verify the ABL's ability to track an airborne target and measure atmospheric turbulence.

The Airborne Laser will aim the illuminators at an instrumented target board located on a missile-shaped image painted on the Big Crow, said Bob Suszek, ABL project manager here.

"We have completed extensive modifications to the ABL aircraft, the system integration lab (here) and the Big Crow target simulator aircraft," Mr. Suszek said. "We're preparing to fly the ABL against some dynamic target engagements which gets us much closer to missile shoot down."

Using the system integration lab, the COIL was fired more than 70 times since November 2004, beginning with a burst of a fraction of a second. Each test-firing increased until a firing on Dec. 6, 2005, when the COIL exceeded the full duration goal at a level believed to be capable of destroying a ballistic missile during the missile's boost phase, or within the first few minutes after it is launched.

Source: USAF Edwards AFB Press Release by Tech. Sgt. Eric M. Grill