By David Alexander
ABOARD THE USS GEORGE H.W. BUSH (Reuters) - An unmanned U.S. jet carried out a maneuver on Wednesday long considered the most challenging in naval aviation - landing aboard an aircraft carrier - in a milestone that lifted expectations about basing drones with reconnaissance and strike capabilities on ships.
A Northrop Grumman X-47B aircraft nicknamed "Salty Dog 502" slipped out of a cloudy sky off the Virginia coast after a flight from Patuxent River Naval Air Station and dropped its tailhook to snag an arresting cable on the deck of the USS George H.W. Bush sailing in the Atlantic Ocean.
"It's not often that you get a chance to see the future, but that's what we got to do today," said Navy Secretary Ray Mabus, who witnessed the landing and likened it to the first manned aircraft landing on a carrier a century ago.
The achievement came as the Navy mulls the role that new ship-carried drones may play in the future for the U.S. military, while some experts question whether these unmanned aircraft are needed by the Navy at all.
The Salty Dog is one of two experimental X-47B aircraft built by Northrop Grumman as part of a program to test the feasibility of integrating unmanned aircraft into carrier operations, which program director Rear Admiral Mat Winter called "the most dynamic and demanding" environment in the Navy.
The X-47Bs will be retired to flight museums in Florida and Maryland after completing a minimum of three arrested landings aboard a carrier in the coming week, officials said.
In their place, the Navy has started the follow-on UCLASS program to design and build unmanned reconnaissance and strike aircraft to be deployed aboard carriers in the coming three to six years.
The start of the UCLASS program with a Navy request for proposed designs from Northrop, Boeing, Lockheed Martin and General Atomics earlier this month has touched off a debate over exactly what the new drone should be and what missions it should take on.
With a stealthy bat-wing air frame, a 2,000-mile (3,200-km) range and the ability to carry the equivalent of two precision-guided bombs, the X-47B raised the prospects of a long-range, radar-evading, unmanned reconnaissance and strike aircraft.
A carrier-based drone with those capabilities could be used to counter countries like China and Iran that have been developing missiles and other weapons aimed at forcing the U.S. Navy to operate far from shore in a conflict.
'TYRANNOSAURUS REX ARMS'
Peter Singer, director of the Center for 21st Century Security at the Brookings Institution think tank, likened the threat to "facing a boxer with really long arms when you've got little Tyrannosaurus Rex arms."
"The idea is you could utilize the UCLASS (carrier drone program) to extend your reach," he said.
The Navy's request for proposed designs appeared less ambitious than some analysts had expected. Rather than seeking proposals for a radar-evading jet with a robust strike capability, the request called for a long-range reconnaissance aircraft able to stay on station for extended periods, Navy officials said.
With the focus on affordability, the drone would not necessarily be able to evade radar - potentially leaving it vulnerable to enemy fire - and it would have only a light attack capability.
Some experts say it is not clear that the Navy needs a carrier-based drone.
They note that such an aircraft's main strength is the ability to remain over a target area for long periods of time looking for potential threats like mobile missile launchers. Land-based drones can provide that capability as effectively as sea-based ones, they say.
"When it comes to operating an unmanned aircraft from carrier decks, the Navy seems to be ambivalent about the whole idea," said Loren Thompson, a defense expert at the Lexington Institute think tank.
He said the Navy needs to conduct a rigorous assessment to see what UCLASS drones would bring to the fleet that cannot be accomplished with manned aircraft or land-based drones.
"Can we fly drones off of aircraft carriers? Yes we can. Is there a good reason for doing so? That's not as clear," Thompson said.
(Editing by Will Dunham)