Update!
The Airborne Laser (ABL) program was killed by the defense secretary in the general slashing of missile defense to reduce the budget of the Missile Defense Agency (MDA) by $1.4 billion in 2010. The ABL will turn into a research program.
The Airborne Laser is now called the "Airborne Laser Test Bed"
UPDATE 2:
The ALTB was officially killed on Feb 16th 2012 and the aircraft will be decommissioned. The Navy's Free Electron Laser will replace this program.
The Boeing YAL-1 Airborne Laser (ABL) weapons system is a megawatt-class chemical oxygen iodine laser (COIL) mounted inside a modified Boeing 747-400F. It is primarily designed as a missile defense system to destroy tactical ballistic missiles (TBMs), similar to the Scud, while in boost phase. The low-power lasers have been test-fired in flight, aimed at an airborne target board. The aircraft was designated YAL-1A in 2004 by the U.S. Department of Defense.
The Airborne Laser Laboratory, a less-powerful prototype installed in a Boeing NKC-135A, shot down several missiles in the 1980s.
The Airborne Laser (ABL) will locate and track missiles in the boost phase of their flight, then accurately point and fire the high-energy laser, destroying enemy missiles near their launch areas.
Capabilities:
* Operates autonomously, above the clouds, outside the range of threat weapons but sufficiently close to enemy territory
* Engages early, destroying ballistic missiles in their boost phase of flight over launch area
* Cues and tracks targets, communicating with other joint theater assets for layered defense system
Unique Technology:
* Nose-mounted turret with 1.5m telescope that focuses beams on missile and collects return image and signals
* Beam Control System to acquire and track targets with precision accuracy
