The US Airforce, Boeing, Lockheed Martin and TRW recently completed a successful series of tests at Lockheed Martin's Advanced Technology Center, Palo Alto, Calif., demonstrating the Airborne Laser (ABL) weapon system will provide lethality consistent with the Air Force's concept of operations when performing in real theater atmospheres. The successful performance of the ABL Beam Control Laboratory Demonstrator (BCLD) answered several critical issues concerning ABL's beam propagation and range performance variability when it is subjected to various levels of real world atmospheric turbulence.

"This is one more step in the incremental build and test philosophy

of the Airborne Laser weapon system," said Paul Shattuck, ABL

program manager for Lockheed Martin. "Our Beam Control risk

reduction activities run the gamut of component technology

maturation, manufacturing, process validation and predictions of

end-to-end system performance. The results from these latest tests

validate the tracking, pointing hardware and algorithms approach

necessary for the ABL weapon system to perform under real world

atmospheric conditions."

Tests performed by the BCLD included three different experiment

arrangements that correspond to atmospheric field data collected by

the Air Force. All experiments conducted by the BCLD demonstrated

sufficient ABL performance, thus indicating acceptable range

variability for these real theater atmospheres.

For the past six years, Team ABL has been predicting the system's

performance with a variety of tools. Multi-prong performance

validation of these predictions was attained by using the following:

Detailed analytic simulation codes that were anchored to real world

and laboratory measurements (i.e., detailed correlation of analytic

results and real world observation)

Scaled tracking, pointing and atmospheric compensation that was

field tested at MIT/Lincoln Lab Firepond, Mass., and White Sands

Missile Range, N.M.

BCLD, which shows ABL capability when using representative beam

control system (BCS) arrangement, engagement geometries (range,

target and velocities) and atmospheres

The BCLD is a tool that will help take the risk out of developing

the ABL system. "The BCLD is a replica of the real ABL Beam

Control system. It maintains careful scaling of diffraction losses,

turbulence effects, and ratio of control to atmosphere bandwidth," said

Shattuck. "Although some ABL optics are not present — for example

the ABL telescope — those that control the high-risk functions are

there in scaled fashion. While full system performance of the real ABL

BCS is not expected, the functional and operational performances are

representative."

The BCLD is especially useful for two purposes. First, it anchors

analytic codes like ABLWOC (adaptive optics and laser beam

propagation predictions) and Pathfinder (platform jitter predictions).

Second, it optimizes component and system performance by making

parametric measurements where performance changes are measured

when a parameter such as optical alignment, fast steering mirror

bandwidth, software algorithm, or atmospheric turbulence is changed.

"Both of these BCLD uses will maintain our vigorous ABL

program to increase fidelity in our performance predictions and to

continue a risk buydown program until the demonstration of missile

shoot-down in year 2002." said Dr. Ken Billman, the BCS chief

scientist.

Team ABL's current Program Definition and Risk Reduction

(PDRR) contract with the Air Force calls for the team to produce,

integrate and flight test the first prototype ABL demonstration system.

The contract is scheduled to culminate in 2002 with a boost-phase

shoot-down of a theater ballistic missile. An ABL engineering,

manufacturing and development (EMD) program could begin as early

as 2003. The PDRR aircraft will provide the Air Force with a residual

operational capability.

Team ABL is led by Boeing, which has overall program

management and systems integration responsibilities. The company is

also developing the ABL battle management system and modifying the

747-400 aircraft. Those efforts will be done at Boeing facilities in

Seattle and Wichita, Kan. TRW, Redondo Beach, Calif., is building the

laser and the related ground-support subsystem, while Lockheed

Martin Missiles & Space, Sunnyvale, Calif., is developing the ABL

target acquisition and beam control systems.