Here we go with the life history of ABL.....
ABL YAL 1A AIRBORNE LASER, USA
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 Defense Organization) 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 $1.1 billion Program 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 were completed in May 2002. 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 the beam control system and lasers. The PDRR phase will culminate in 2004 with the destruction of a missile and ABL is planned to enter production from 2006 to 2008. Initial operational capability with three aircraft will be achieved by 2006 and full operational capability with seven aircraft by 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
The ABL is designed to detect and destroy theatre ballistic missiles in the powered boost phase of flight immediately after missile launch. The aircraft loiters at an altitude of 40,000 feet. 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 km.
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 1.5 metre 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.
http://www.airforce-technology.com/projects/abl/
Before the Air Force even conceived of the airborne laser (ABL), Air Force personnel, contractors, and scientists worked at Kirtland AFB, New Mexico, to develop a laser capable of shooting down a missile. Robert Duffner’s well-documented history mixes physics and personal accounts to trace the development of military lasers from 1958. The task, then as today, was to develop a weapon that could destroy a missile in flight. Doing so required not only a powerful laser but also a tracking mechanism to keep a beam focused on a rapidly moving object. All pieces of such a system were developed at Kirtland over a period of 30 years.
Following the proposal to develop the ABL, the next two decades were spent perfecting chemicals and optics that would make such a device possible. In 1969 Gen John Ryan, chief of staff of the Air Force, authorized an increase in funding and paved the way for feasibility demonstrations since the project showed promise. Hans Mark, secretary of the Air Force, and Harold Brown, secretary of defense, also backed the program.
After more development work, most components of a ground-based test-laser assembly were fitted into an NKC-135 airborne laser lab (ALL). A second KC-135 was modified to act as the diagnostic aircraft, which would receive telemetric data from the ALL and targets. In the event of an explosion from the pressurized chemicals the ALL used to conduct laser tests, the diagnostic aircraft would be able to determine what had happened. After the usual setbacks that accompany such high-technology tests, the ALL successfully shot down a variety of test items, such as an AIM-9 Sidewinder and a BQM-34 drone.
After its successes in 1983, the ALL continued to serve as a test bed for laser experiments. In 1984, however, the aircraft went into flyable storage at Kirtland and in 1988 was retired and flown to the Air Force Museum at Wright-Patterson AFB, Ohio. This successful program gave the Air Force its first-generation laser and pointer/tracker. Currently, the Air Force is working on its second-generation system—an ABL mounted in a 747-400F—which should enter the inventory in 2006.
Since Airborne Laser provides the best history of developments leading to the ABL, I highly recommend it to any Air Force officer or to anyone interested in laser applications. Well illustrated, this technological success story covers the entire developmental work on airborne lasers, problems encountered, and solutions reached—all in writing that nonscientists can understand.
http://www.airpower.maxwell.af.mil/a...00/duffner.htm
http://www.findarticles.com/p/articl...15/ai_75578155