Missing plane: Could these vehicles find MH370?
15 April 2014 Last updated at 23:54 BST
The first mission by the Bluefin submarine in the search for missing flight MH370 was cut short, and according to the US Navy, failed to find any objects of interest, on Monday.
The robotic device is to go back into the water later - to spend its second day searching the bottom of the Indian Ocean.
Richard Westcott takes a closer look at the vehicles which could be used to find the plane.