All three systems use sensors to detect missile launches and lasers to blind the infrared seekers that home in on hot jet exhaust.
The newest of the three proved itself in tests Sept. 8 and 9 at Holloman Air Force Base, N.M., Northrop says.
From an altitude of 50,000 feet, an infrared sensor was able to detect a missile launch, relay the information to an onboard missile tracker and then hit the missile with a blast from a laser, said Jack Pledger, Northrop's director of infrared countermeasures.
To the Department of Homeland Security, which paid Northrop $6.6 million to develop the system it calls Project Chloe, the results "look very promising," DHS spokesman John Verrico said.
Cost has been a major obstacle in the effort to protect commercial airliners from the threat of shoulder-fired missiles, but UAV-mounted missile defense systems might make protecting airports more affordable.
It's simple economics, said Kerry Wilson, Project Chloe program director. It would be cheaper to build a fleet of missile-jamming UAVs than to install missile defenses on each of the nation's 6,800 commercial airliners.
DHS has spent at least $230 million since 2004 on contracts with Northrop, BAE Systems, United Airlines, FedEx and other companies to develop and test missile defense systems.
Laser jammers that would be installed on individual aircraft emerged as the preferred technology, and the department set a goal of reducing the cost of missile-jamming systems to $1 million or less per airliner.
Pledger said Northrop has met that goal. But equipping the U.S. airline fleet with missile jammers would cost about $6 billion. Airlines, reeling under increased fuel costs and massive financial losses, are in no position to buy the defense systems. The deficit-plagued U.S. government is also unwilling to do so.
Looking for ways to "cover the most aircraft with the least money," DHS hit on the idea of putting missile defense systems on UAVs, Verrico said.
Loitering at 65,000 feet, a single UAV could monitor an area 50 miles across. In the Washington area, for example, a single UAV could provide missile defense for Dulles, Reagan National and Baltimore-Washington airports, Verrico said.
By contrast, a ground-based system might not be able to protect an entire airport where planes are landing at one end and taking off at the other, he said.
High-flying UAVs armed with missile jammers might also prove valuable to the U.S. military in areas where the threat of attack by shoulder-fired missiles is high, such as Baghdad International Airport, Pledger said. There pilots have resorted to steep, corkscrew landings ever since a commercial cargo plane was hit by a shoulder-fired missile in 2003.
Pledger said Northrop has not calculated the cost of laser-armed UAVs, but individual units won't be cheap.
"The system that goes on the UAV would probably be much more expensive than the system that goes on an airplane because of the advanced technology we have to put into it," he said. "Then you have the cost of the UAV, operation of the UAV and all of the support structure."
And there's a lot more work to be done before Northrop's UAV-based missile defense system is ready for service, Pledger cautions.
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