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Underwater robots at work in Japan

Karen Dreger, CRASAR

Underwater robots, including the SARbot shown here making a test dive on Tuesday, are at work in Japan searching the murky coastal waters for debris, infrastructure damage, and survivors.

Underwater robots equipped with imaging sensors that can see through murky waters are at work inspecting bridges, docks, and pipelines in port areas of the earthquake- and tsunami-ravaged coastline of Japan.

The robots, between the size of a suitcase and football, join other robots inspecting the crippled nuclear reactors at the Fukushima Dai-ichi plant. On Monday, those robots reported that radiation levels are too high for human repair crews.

Robin Murphy, director of the Center for Robot-Assisted Search and Rescue at Texas A&M University, in College Station, and one of the world's top experts in rescue robotics, told me in the days after the disaster that underwater robots could also be of use in Japan. All she needed was an official invitation. 

Port deployment
That invitation came and her team, in partnership with Tetsuya Kimura of the Nagaoka University of Technology, deployed the robots Tuesday at the fishing port Minami-sanriku-choy to look for debris and other threats in the cloudy waters that could block passage of fishing boats, which need at least 15 feet of clearance before they can return to work.

On Wednesday, Murphy reported that the port was clear of obstructing debris, and that the robots "performed admirably."

"We were surprised at the lack of cars and other big objects underwater. The lower portions of the town is one rumbled mass of cars, piers, metal pilings, and such all twisted about, so we expected to see at least some of the same in the water," she  wrote in a blog post from the field. 

The team primarily encountered anchor stones and ropes used in the harbor and some smaller bits of debris. The lesson learned, Murphy notes, is a need for simulation software that predicts where debris goes in the wake of a tsunami or hurricane. 

No bodies of victims were found, which Murphy said is bittersweet. Minami-sanriku-choy had a population of 20,000. An estimated 2,000 people are dead or missing following the disaster. 

Similar to BP effort
The robots in use are smaller versions of the types used during the BP oil spill. They include the suitcase-sized Seamor, which can spot objects of interest with sonar capabilities and Seabotix's SARbot, which can zero in on the objects.

Other equipment in the team's arsenal includes the football-sized AC-ROV robot and monitoring equipment for AEOS Inc. All of the robots have a tether to allow operators on the surface to control the vehicles in real-time and watch the sonar and video footage. 

The team is now moving to Rikuzen-Takada to continue the search-and-rescue efforts. Murphy will update her blog as time permits.

Red Whittaker, a robotics expert at the Carnegie Mellon Robotics Institute, told me in March to expect robot deployments that help Japan recover from the earthquake and tsunami to last for weeks, months, and years.

"These are campaigns, not skirmishes, and typically new tools are brought to bear as the challenges arise and those challenges are very different over time," he said.

More coverage on robots in Japan:

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).