MIT researchers revealed a small "oval-shaped submersible robot" that has a flattened panel allowing it to perform ultrasounds on underwater objects.

The device was originally designed to look for cracks in nuclear reactors' water tanks, but it could also be used to inspect ship hulls and propeller shafts that are often used in contraband smuggling.

The robot is smaller than a football and has a unique propulsion method that leaves behind only a very gentle wake; these features could allow it to be easily hidden in clumps of algae or other camouflages.

"It's very expensive for port security to use traditional robots for every small boat coming into the port," said Sampriti Bhattacharyya, a graduate student in mechanical engineering. "If this is cheap enough - if I can get this out for $600, say - why not just have 20 of them doing collaborative inspection? And if it breaks, it's not a big deal. It's very easy to make."

The researcher was able to build the robot's body using a 3-D printer. The robot is inherently unstable, similar to a fighter jet, so it can be easily maneuvered underwater. The device features a watertight chamber containing its "control circuitry, its battery, a communications antenna, and an inertial measurement unit" as well as a propulsion system made up of six pumps that expel water through rubber tubes. The robot runs on lithium batteries that last for about 40 minutes, which should give it ample time to inspect a number of crafts before needing to be recharged.

The device has not been tested with the ultrasound yet, but the next prototype will feature wirelessly rechargeable batteries which could increase its operation time to 100 minutes.

"I am particularly interested to see if this type of technology could find use in domestic maritime operations ranging from the detection of smuggled nuclear, biological, or chemical agents to drug interdiction, discovery of stress fractures in submerged structures and hulls, or even faster processing and routing of maritime traffic," said Nathan Betcher, a special-tactics officer in the U.S. Air Force.

The research was funded by the National Science Foundation and was presented at the International Conference on Intelligent Robots and Systems.