Aircraft

Stretched freighter offers longer range, more room and new technologies, as preparations continue for 2008 test

Boeing has begun company-funded studies into using the new 747-8F freighter, instead of the 747-400F, as the platform for the US Air Force’s Airborne Laser (ABL) missile defence system. Although a decision on whether to produce further ABL systems will not be taken until after a shoot-down test planned for 2008, the only new-build platform available by then will be the new 747-8.

The YAL-1 ABL prototype – dubbed “Tail 1” – is a heavily modified 747-400 freighter, and the stretched -8 offers several potential advantages, says Greg Hyslop, vice-president and ABL programme director. “The 747-8 has longer range and more room, plus new technologies that could make it easier to integrate the mission system,” he says.

Lacking funding from the US Missile Defense Agency, Boeing is spending company money on design of a production ABL.

“There is no formal decision on a second aircraft, but we are looking at various configurations,” says Hyslop. “We are investing our own funds to find synergy between the next ABL and the 747-8, to make it easier to integrate,” he says.

As the six-module high-energy chemical laser in the 747-400 already provides lethal power, Boeing is looking at the extra space inside the -8 for carrying more laser fuel and to make the system more maintainable, Hyslop says. Boeing is aiming for a more producible laser system and a quicker aircraft modification for Tail 2, he adds.

Among design changes being considered are refinement of the nose-mounted turret to provide more robust beam control and allow the ABL to operate at a higher speed. The airspeed at which the prototype can fire its laser is limited by the need to keep the shockwave behind the nose to avoid aero-optical effects on the beam, according to Hyslop.

Boeing is completing ground tests of the ABL using a low-power surrogate laser. These will be followed later this year by flight tests to measure tracking, illumination and atmospheric-compensation performance against a Boeing KC-135 modified to simulate a ballistic-missile target.

The high-energy laser will be re-installed next year for tests leading up to the shoot-down demonstration in 2008.