Bluefin 21

Bluefin 21

In this handout image provided by the U.S. Navy, The Bluefin 21, Artemis autonomous underwater vehicle (AUV) is hoisted back on board the Australian Defence Vessel Ocean Shield after successful buoyancy testing April 1, 2014 in the Indian Ocean. Photograph: Mass Communication Specialist 1st Class Peter D. Blair/U.S. Navy via Getty Images