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:

For more information, read the Airborne Laser (ABL) (PDF) overview, the Missile Defense Agency Airborne Laser Fact Sheet (PDF) and the Defense Daily (PDF) Supplement on ABL. - (Archived)

Related Links:

• Airborne Laser Tracks and Engages A Missile in Flight
• Airborne Laser Test Bed - Boeing
• ABL YAL 1A Airborne Laser, USA
• Airborne Laser - FAS.org

• Airborne Laser (ABL): Issues for Congress - (Archived)

Boeing's high-tech YAL-1 Airborne Laser (ABL) weapons system consists of a high energy laser, flight turret assembly, tracker Illuminator lasers, and a beacon illuminator -- to be installed on modified 747-400Fs. Simply put, it first uses infrared sensors to detect missiles, then three low power tracking lasers calculate speed/aimport, and lastly, the main laser is fired for 3-5 seconds from a front-mounted turret. 

ABL YAL 1A Airborne Laser, USA
Airforce Technology (undated) 2006

The US Air Force Airborne Laser, (ABL), designated YAL-1A, is a high-energy laser weapon system for the destruction of tactical theatre ballistic missiles, which is carried on a modified Boeing 747-400F freighter aircraft.

The ABL is being developed by the Air Force Research Laboratory and Team ABL, comprising Boeing, TRW (now Northrop Grumman Space Technologies) and Lockheed Martin.

Boeing is responsible for program management, systems integration, battle management system and modification of the 747-400F aircraft. TRW Inc is building the laser systems. Lockheed Martin Space Systems is responsible for the target acquisition and beam control systems.

The US Missile Defense Agency (previously called the Ballistic Missile Defence Organisation) is responsible for the management of the program and it is executed by the USAF from Kirtland AFB in Albuquerque, New Mexico.

In 1996, the Department of Defense awarded Team ABL a $1.1bn Programme Definition and Risk Reduction (PDRR) contract for the development and test of an airborne laser weapon system. During tests at TRW's Capistrano test site in 1998, the laser demonstration module achieved a power level 10% higher than the requirement. In April 2000 the ABL final critical design review was completed.

Modification of the aircraft, involving installation of the turret in the aircraft's nose and modifications to accept the laser, optics and computer hardware, was completed in May 2002.

The FLM testing one of several risk reduction activities that Team ABL, Boeing, Northrop Grumman Space Technologies and Lockheed Martin have conducted.

In July 2002, the modified aircraft took the first of a series of test flights. After receiving airworthiness certification, the aircraft was flown to Edwards Air Force Base, California, in December 2002, for the installation of systems. The aircraft returned to airworthiness flight testing in December 2004 following installation of the beam control / fire control system.

In November 2004, all six modules of the COIL laser were successfully fired for the first time. In August 2005, the ABL completed a series of flight tests demonstrating the performance of the beam and flight control systems. The BILL laser was delivered in January 2006.

In February 2007, the ABL began a series of flight tests, which included the first in-flight firing of the TILL targeting laser at a simulated target, in March 2007. This is being followed by flight tests of the BILL illuminating laser. The COIL laser is to be installed in 2007. The first prototype is scheduled for completion in 2008 with the first missile shoot-down test later that year. A second system is being considered, to begin design in 2008.

ABL SYSTEMS

The ABL aircraft carries the COIL laser which generates the killer laser beam, an infrared surveillance and high speed target acquisition system and a high precision laser target tracking beam control system.

The laser weapon uses three laser beam systems: the powerful killing laser beam or primary beam, a set of illuminating laser beams and a beacon laser.

The primary laser beam is generated by a megawatt Chemical Oxygen Iodine Laser (COIL) located at the rear of the fuselage, which lases at 1.315 micron wavelength. The high-power laser beam travels towards the front of the aircraft through a pipe. The pipe passes through a Station 1000 bulkhead / airlock, which separates the rear fuselage from the forward cabins. The high power beam passes through the fine beam control system mounted on a vibration isolated optical bench. Beam pointing is achieved with very fast, lightweight steering mirrors, which are tilted to follow the target missile.

A low-power, multiple beam, Track Illuminating Laser (TILL), being developed by Raytheon Electronic Systems, is used to determine the target's range and provides initial information on the atmosphere through which the beam is being transmitted. The illuminating laser tracks the target and provides aiming data for the primary beam.

The Beacon Illuminating Laser (BILL) has been developed by Northrop Grumman Space Technology. The kilowatt class BILL reflects light from the target to provide data on the rapidly changing characteristics of the atmosphere along the path of the laser beam. This data is used to control a set of deformable mirrors in the beam control system. The mirrors introduce tailored distortions into the COIL laser beam to compensate for atmospheric distortions and allow the COIL laser beam to fall on the target.

OPERATION

Missile launch is detected by a reconnaissance system such as satellite or Airborne Warning and Control System (AWACS) aircraft and threat data is transmitted to the ABL aircraft by Link 16 communications.

A suite of infrared, wide-field telescopes installed along the length of the aircraft's fuselage detects the missile plume at ranges up to several hundred kilometres.

The pointing and tracking system tracks the missile and provides launch and predicted impact locations. The turret at the nose of the aircraft swivels towards the target and a 1.5m telescope mirror system inside the nose focuses the laser beam onto the missile. The laser beam is locked onto the missile, which is destroyed near its launch area within seconds of lock-on.

Where the missile carries liquid fuel, the laser can heat a spot on the missile's fuel tank, causing an increase in internal pressure resulting in catastrophic failure. Alternatively, the missile is heated in an arc around its circumference and crumples under atmospheric drag force or its own g-force.

SOURCE: Airforce Technology

Airborne Laser
FAS.ORG
May 30, 2008

The ABL weapon system consists of a high-energy, chemical oxygen iodine laser (COIL) mounted on a modified 747-400F (freighter) aircraft to shoot down theater ballistic missiles in their boost phase. A crew of four, including pilot and copilot, would be required to operate the airborne laser, which would patrol in pairs at high altitude, about 40,000 feet, flying in orbits over friendly territory, scanning the horizon for the plumes of rising missiles. Capable of autonomous operation, the ABL would acquire and track missiles in the boost phase of flight, illuminating the missile with a tracking laser beam while computers measure the distance and calculate its course and direction. After acquiring and locking onto the target, a second laser - with weapons-class strength - would fire a three- to five-second burst from a turret located in the 747's nose, destroying the missiles over the launch area.

The airborne laser would fire a Chemical Oxygen Iodine Laser, or COIL, invented at Phillips Lab in 1977. The laser's fuel consists of the same chemicals found in hair bleach and Drano - hydrogen peroxide and potassium hydroxide - which are then combined with chlorine gas and water. The laser operates at an infrared wavelength of 1.315 microns, which is invisible to the eye. By recycling chemicals, building with plastics and using a unique cooling process, the COIL team was able to make the laser lighter and more efficient while - at the same time - increasing its power by 400 percent in five years. The flight-weighted ABL module would be similar in performance and power levels to the multi-hundred kilowatt class COIL Baseline Demonstration Laser (BDL-2) module demonstrated by TRW in August 1996. As its name implies, though, it would be lighter and more compact than the earlier version due to the integration of advanced aerospace materials into the design of critical hardware components. For the operational ABL system, several modules would be linked together in series to achieve ABL's required megawatt-class power level.

Atmospheric turbulence, which weakens and scatters the laser's beam, is produced by fluctuations in air temperature [the same phenomenon that causes stars to twinkle]. Adaptive optics rely on a deformable mirror, sometimes called a rubber mirror, to compensate for tilt and phase distortions in the atmosphere. The mirror has 341 actuators that change at a rate of about a 1,000 per second. 
The Airborne Laser is a Major Defense Acquisition Program. After the Concept Design Phase is complete, the ABL will enter the Program Definition and Risk Reduction (PDRR) Phase. The objective of the PDRR phase is to develop a cost effective, flexible airborne high energy laser system which provides a credible deterrent and lethal defensive capabilities against boosting theater ballistic missiles. 

The ABL PDRR Program is intended to show high confidence system performance scalable to Engineering and Manufacturing Development (EMD) levels. The PDRR Program includes the design, development, integration, and testing of an airborne high-energy laser weapon system. 

In May 1994, two contracts were awarded to develop fully operational ABL weapon system concepts and then derive ABL PDRR Program concepts that are fully traceable and scaleable EMD. A single contract team was selected to proceed with the development of the chosen PDRR concept beginning in November 1996. Successful development and testing of the laser module is one of the critical 'exit criteria' that Team ABL must satisfy to pass the program's first 'authority-to-proceed' (ATP-1) milestone, scheduled for June 1998. Testing of the laser module is expected to be completed by April 1998. The PDRR detailed design, integration, and test will culminate in a lethality demonstration in the year 2002. A follow-on Engineering Manufacturing and Development/Production (EMD) effort could then begin in the early 2003 time frame. A fleet of fully operational EMD systems is intended to satisfy Air Combat Command's boost-phase Theater Air Defense requirements. If all goes as planned, a fleet of seven ABLs should be flying operational missions by 2008.

Performance requirements for the Airborne Laser Weapons System are established by the operational scenarios and support requirements defined by the user, Air Combat Command, and by measured target vulnerability characteristics provided by the Air Force lethality and vulnerability community centered at the Phillips Laboratory. The ABL PDRR Program is supported by a robust technology insertion and risk reduction program to provide early confidence that scaling to EMD performance is feasible. The technology and concept design efforts provide key answers to the PDRR design effort in the areas of lethality, atmospheric characterization, beam control, aircraft systems integration, and environmental concerns. These efforts are the source of necessary data applied to exit criteria ensuring higher and higher levels of confidence are progressively reached at key milestones of the PDRR development. 

The key issues in the program will be effective range of the laser and systems integration of a Boeing 747 aircraft. 

SOURCE: FAS.ORG