The U.S. military is experimenting with airborne lasers to shoot down ballistic missiles fired in combat.
Modified 747 Aircraft
The U.S. Air Force has been testing the Boeing YAL-1 Airborne Laser, which has been developed to target and destroy Tactical Ballistic Missiles. The weapon system uses a Chemical Oxygen Iodine Laser that has been affixed to the nose of a modified Boeing 747 aircraft. Once targeted, the laser system heats a ballistic missile from the inside out and causes it to explode. Tests have shown that the YAL-1 system is capable of shooting down a missile within 10 seconds from a distance of several hundred miles.
The U.S. Air Force first tested the Boeing YAL-1 Airborne Laser in 2002. Several more tests were conducted in 2007 and 2010. In the tests, the laser system successfully identified and destroyed several incoming missiles. The system has attracted a lot of attention from defense and security experts who see it as a way to protect U.S. soldiers and, potentially, U.S. territory from attacks by ballistic missiles. Some defense experts predict that a laser system similar to the Boeing YAL-1 could be developed and used in the future against enemy fighter jets, satellites and cruise missiles.
Over Budget
The Boeing YAL-1 Airborne Laser system is being developed by a consortium of leading defense contractors that includes Boeing Defense, Space & Security, Lockheed Martin Corp., and Northrop Grumman Corp. Despite the initial success of the tests involving the Boeing YAL-1 Airborne Laser, the advanced program has gone more than $6 billion over budget. As of late 2010 the U.S. Air Force has not requested additional funding for the project or scheduled more tests of the system.

