DARPA's Robotic Ghost Ships Will Stalk Submarines

Robot Frigates Now imagine this ship without the people U.S. Navy/Scott Taylor

From Popular Science:

Ships that appear in perfect working order except for a missing human crew would normally raise suspicions that something has gone terribly wrong, possibly in the vicinity of the Bermuda Triangle. Yet an unmanned frigate is exactly what DARPA's mad scientists at the Pentagon have ordered, according to The Register. The automated ships' mission would have it spending months cruising the seas unmanned, on the hunt for ghostly enemy submarines.

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My Comment: The tech and engineering to pull this off will be impressive .... and probably very expensive (even with a skeletal or unmanned crew).