Created in MIT's Autonomous Underwater Vehicles Laboratory, the Odyssey IV can hover like a helicopter, enabling applications like inspecting deepwater oil rigs, observation of sea-bottom flora and fauna and other oceanographic research.

The MIT lab has been designing and building undersea robots since the 1990s, but researchers claim the Odyssey IV is the first model to hover like a helicopter. The Odyssey IV completed its initial trials off Woods Hole, Mass., where it proved it can hover at depths of up to 6,000 meters (3.7 miles).

The Odyssey IV undersea robot hovers like a helicopter using four TH-2100 thrusters made by Deep Sea Systems International.

The Odyssey IV maintains it hovering capability using the coordinated action of fins and thrusters--like undersea retrorockets--located on the sides, bow and stern of the 2-meter-long robotic submarine. Its four thrusters are were supplied by Deep Sea Systems International.

Previous undersea robots could only navigate over a scene, take a picture, then repeat the maneuver, according to Chryssostomos Chryssostomidis, director of the MIT Sea Grant Program. But the Odyssey IV can hover over a scene to make detailed observations and measurements, Chryssostomidis said.

Besides cameras, the Odyssey IV also has a robotic arm that enables it to pick up samples and return them to shore or to open or close a valve on an oil platform.

The robot also can maintain speeds of up to 2 meters per second (4.5 miles per hour).

The Odyssey IV's microcontroller programmed by MIT students monitors the currents in a water column, then calculates the amount and direction of thrust to maintain its position in the water.

Previous programming efforts enabled Odyssey IV's predecessors to navigate to preprogrammed destinations as well as to operate under remote control. But with the addition of the new "hover" capability, MIT researchers claim the Odyssey IV can execute more complex maneuvers that take advantage of sea currents. It also can avoid both stationary and moving obstacles. Odyssey's first test was assisting Sea Grant researcher Judy Pederson in mapping and photographing the George's Bank area where an invasive species of sea squirt called Didemnum has been destroying habitat for local fish.

The MIT team plans to improve the ability of the submarine to navigate for longer periods, with the eventual goal of year-long underwater missions without the need to surface. To achieve that goal, improvement are needed for battery and data storage and wireless communications capabilities. They also are experimenting with more versatile robotic arms capable of performing complex underwater repairs and sample collection.