Robots not smart enough yet for Navy deep-ocean missions.

• Author: Erwin, Sandra I.

Searching for downed airplanes and sunken ships in deep ocean waters--and raising them to the surface--are laborious operations that have yet to benefit from futuristic robotics technologies.

Since a U.S. Navy remotely operated vehicle successfully recovered a nuclear bomb in 2,800 feet of ocean water nearly four decades ago, sensors and other technologies have advanced significantly--even though the basic techniques remain essentially the same.

The big breakthrough that the robotics industry has been seeking for the past 20 years--autonomous vehicles that can think independently--is finally here, but the technology is not yet mature or affordable enough for most users of deep-ocean salvage equipment.

Among the most cumbersome features of current underwater vehicles is the umbilical cable, which slows down the search process, particularly when the area being probed is 10,000 or 20,000 feet deep, says Tom Salmon. He is in charge of salvage operations and ocean engineering under the Navy's supervisor of salvage and diving, known as SUPSALV.

The agency has been involved in high-profile salvage operations, such as the recovery of the Japanese trawler Ehime Maru--sunk in the Pacific last year after a collision with the submarine USS Greenville--and the lifting last month of the 160-ton gun turret of the Civil War vessel USS Monitor.

The current generation of tethered sonar search systems, says Salmon, might be replaced with autonomous underwater vehicles within a decade, if the technology matures.

"We've probably built our last deep-ocean search system" that operates with an umbilical, he says. "Sometime in the next 10 years, I would predict that we'll be going untethered, at least for search vehicles."

There is more than one definition for vehicle autonomy, Salmon explains. Under one concept, the vehicle dives and conducts a preprogrammed search. It then comes back to the surface, so operators aboard the ship can download the data and images of what the submersible saw.

Under a more advanced form of autonomy, the vehicle would be linked acoustically, through the water, to the ship. If the submersible found a potential target, the human operator could instruct it to hover over a spot, take pictures and transmit them. "That's the true autonomous system, Salmon notes. That technology is not ready for prime time. Nevertheless, he says, "I think we are getting a lot closer than I ever thought we would during my career."

In the short term, Salmon says, SUPSALV officials would like to see increased use of untethered search systems, such as side-scan sonar or TV cameras. Current tethered devices commonly are...