Hovering about

A new robotic underwater vehicle can hover in place like a helicopter - an invaluable asset for deepwater oil explorers, marine archaeologists and oceanographers.

Developed by researchers at MIT, the new craft, called Odyssey IV, is the latest in a series of small, inexpensive, artificially intelligent submarines developed over the last two decades by the MIT Sea Grant College Program's Autonomous Underwater Vehicles Laboratory.

While previous Odyssey vehicles could only operate while continuously moving forward, the Odyssey IV, which has just completed sea trials off Woods Hole, Massachusetts, doesn't have that problem.

It can move through the deep ocean, up to 6,000m down, stopping anywhere in the water column and constantly correcting for currents and obstacles. Navigating to its preprogrammed destination, it can hover in place, making detailed inspections of the footings of an offshore oil platform, or photographing the flora and fauna around an undersea vent.

'In the past, you could only fly over a scene, take a picture, then fly over again and take another picture. Now, I can stop over a scene that's of interest, and stay and make measurements,' said Chryssostomos Chryssostomidis, director of the MIT Sea Grant Program.