The robot apocalypse came a step closer as Northrop Grumman and the US Navy carried out a successful carrier-style landing of the X-47B Unmanned Combat Air System (UCAS) demonstrator. The test, which was carried out on May 4 at the Naval Air Station Patuxent River in Maryland, used a land-based version of an aircraft carrier cable-arrested landing system as the beginning of the final phase of testing prior to carrier-based trials planned for later this month.

Landing on an aircraft carrier is one of the most hair-raising maneuvers a pilot can carry out. Even the most jaded has sweaty palms while guiding in a 60-million dollar aircraft at hundreds of miles an hour to land on a flight deck that looks about the size of a chocolate bar. Watching an autonomous unmanned aircraft try the same thing is almost as bad, but if combat UAVs like the X-47B are to become part of the fleets of the future, they’ll need to master the art so they don’t end up as piles of high tech scrap.

Saturday’s test was a cable-arrested landing, which is the technique that allows high-speed aircraft to land on a short carrier deck with relative safety. During landing, the aircraft deploys a landing hook that snags a heavy cable strung across the flight deck. As the cable plays out, it absorbs the energy of the plane and quickly brings it to a controlled stop. In the X-47B’s case, this system was set up on an airfield rather than an aircraft carrier, but the navigation approach was designed to simulate that of carrier operation.

The landing was the highlight of three three months of shore-based carrier testing , which included precision approaches, touch-and-go landings, and precision landings. Carl Johnson, vice president and Navy (UCAS Carrier Demonstration) UCAS program manager for Northrop Grumman said, "The X-47B air vehicle performs exactly as predicted by the modeling, simulation and surrogate testing we did early in the UCAS-D program. It takes off, flies and lands within a few feet of its predicted path."

Under a contract with the US Navy, Northrop Grumman built two X-47B demonstrators. Though the X-47B is unmanned, it is not a drone. Instead, it’s an autonomous aerial vehicle, which means that it flies missions according to pre-programmed instructions rather than being under constant control by a ground-based pilot.

It’s designed to demonstrate autonomous carrier operations including launch, recovery and operations within 50 nautical miles (57.5 mi, 92.6 km) of the carrier. One of the two built is designed for autonomous aerial refueling operations using both the Air Force “boom/receptacle” approach and the Navy “probe and drogue” method. No weapons are carried by either and no sensor tests are planned.

The Navy will be soon be conducting carrier landing tests and autonomous aerial refueling demonstrations are planned for 2014.

The video below shows the arrestor cable landing of the X-47B.

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