HIGH MARK FOR UNMANNED JETS.

Byline: Jim Skeen Staff Writer

EDWARDS AIR FORCE BASE - In a step toward creating robotic combat jets, two experimental unmanned aircraft passed their ``graduation'' test by making a coordinated attack on simulated air defense targets.

Two Boeing X-45A jets finished three years of flight tests with the simulated combat mission Wednesday during which they showed they could identify, attack and destroy ground-based radar and missile launchers before missiles could be launched against them, officials said.

``We pushed the X-45As to their limits and they responded brilliantly,''

said Darryl Davis, Boeing Global Strike Solutions vice president.

The jets by themselves decided which was in the best position to attack the highest-priority target. The aircraft also successfully avoided another simulated anti-aircraft site that popped up on their flight to the target, Boeing and Defense Advanced Research Projects Agency officials said.

Once the pilot at the ground control station authorized the attack, the X-45A aircraft simulated dropping weapons on the target. After ``destroying'' a second simulated target, the two X-45As flew back to land at Edwards, program officials said.

The J-UCAS program is a joint effort by DARPA, the Pentagon agency that financed the early development of the stealth fighter, and the Air Force and the Navy to change the nature of air combat.

The goal is an unmanned aircraft that can take on very dangerous missions, such as attacking enemy radar and missile sites, as well as lower-level tasks, such as surveillance missions that last for hours.

Program officials want stealthy, unmanned aircraft that can be launched either from land or an aircraft carrier and can fly 1,500 miles carrying 4,500 pounds of weapons and electronic gear.

The next generation of experimental unmanned combat aircraft is in development.

Boeing is developing the X-45C, which will be 39 feet long, compared with 27 feet for the X-45A.

Northrop Grumman is leading a team that is developing the X-47B. That aircraft will be just over 38 feet long and will have a wingspan of 62 feet. The wings can be folded to reduce the width to 30 feet.

The X-45A's last mission demonstrated a capability that Pentagon officials want in future unmanned combat aircraft - the ability for them to operate on their own with a human operator on the ground making the key decisions, such as whether to proceed with an attack.

``This demonstration concludes an exciting and precedent-setting time,'' said Michael Francis, DARPA's J-UCAS program director.

The X-45A aircraft made 64 flights at NASA's Dryden Flight Research Center without a mishap, officials said.

In 2007, Defense Department officials will begin an assessment of the larger X-45C and X-47B jets. That testing, which could run through 2010, will provide information about capabilities to be pursued in follow-up developments.

Jim Skeen, [phone]

james.skeen(at)dailynews.com