The director of the U.S. Missile Defense Agency (MDA) says he is pleased with the performance of the Airborne Laser’s (ABL) mission systems to date, but the 747-400F platform has recently had problems with flight worthiness.

U.S. Army Lt. Gen. Patrick O’Reilly says ABL’s laser has been fired and displayed atmospheric compensation beyond 100 kilometers (60 miles) 12 times, most recently in a test flight last weekend. The laser’s ability to compensate for particles in the atmosphere that can dissipate the laser energy is a key criterion to the success of the system.

Also, the system is able to assess what atmospheric compensation is needed within 1/100th of a second, O’Reilly says, a relevant result for operational use of a future ABL-type system. ABL’s mission is to lase the motor of boosting ballistic missiles in the boost phase of flight and destroy them.

O’Reilly says he is approaching ABL with a “three strikes” philosophy. First, the system will be tested against a Scud-type target as early as September (possibly slipping into October). If that is unsuccessful, he says he’ll try a shootdown again at year’s end. The final opportunity will be next spring. If each attempt results in failures, O’Reilly says he will have to brief Defense Secretary Robert Gates on whether and, if needed, how to proceed with the multibillion dollar effort.

Prior to the shootdown test this fall, engineers will be swapping out ABL’s optical system, adding new “second generation” optics that are more tolerant to contamination, O’Reilly says.

One challenge for the program is that its 747-400F platform “gets cranky,” he adds. Problems have emerged with the hydraulics and brakes of the aircraft, largely because it has been on the ground while the laser modules were being installed on the aircraft.

“After initial startup problems, the aircraft has returned to flight and is flying regularly,” according to Michael Rinn, vice president for Boeing’s ABL program. “We flew several times in the last week, which indicates the startup problems are rapidly going away,”

In the fiscal 2010 DOD budget request, Gates proposes keeping ABL as a research project only, eliminating any chance the system as designed will be fielded. O’Reilly concurs with that approach, adding that continuing tests on the chemical-laser system are useful for potential application to future systems.

Photo: Northrop Grumman