Scouting for enemy submarines may soon be done by an autonomous ship. DARPA recently handed off its self-driving vessel prototype to the U.S. Navy after completing a series of successful trials. The ship, nicknamed Sea Hunter, is capable of spending months at sea without a crew. It's not weaponized and can reach speeds of up to 27 knots.

The 132-foot Sea Hunter has been in development since 2012 and cost $20 million to build. DARPA says the ship could be operational later this year.