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A Bluefin-21 autonomous underwater vehicle (AUV), similar to the one searching the ocean floor for Flight 370, is launched into Boston Harbor during a recent testing mission.


Can an Unmanned Mini Yellow Submarine Find Missing Flight 370?

The undersea search could take two months. Or longer.

For now, the best hopes for finding Malaysia Airlines Flight 370 ride on a mini yellow submarine named Artemis, after the Greek goddess of hunting.

The 21-foot (6.4-meter) unmanned submersible is scouring the remote depths of the southern Indian Ocean, nearly 3 miles (4.8 kilometers) beneath the surface. (Related: "Searching for the Missing Malaysian Jet at the Ends of the Earth.")

The work is painstakingly slow. Australia's Prime Minister Tony Abbott cautioned last weekend that scouring the latest search zone of 18,000 square miles (46,600 square kilometers) could take six to eight weeks. That may have been optimistic.

As if to underscore the point, Artemis's very first dive was aborted 6 hours into a 16-hour seafloor cruise on Monday when the sub ventured too deep. Built-in safety features sent it back to the surface.

Then more bad weather rolled in, forcing more delay. When the weather cleared on Tuesday, Artemis returned to the ocean bottom, aided by a British survey ship that is running survey lines to help define the depths. Artemis is rated to operate to depths of 2.8 miles (4.5 kilometers).

"There are no charts for this area that have any accuracy," says Jim Gibson, general manager of Phoenix International, the Maryland salvage company contractor that owns and operates the sub on contract to the U.S. Navy.

That is only one of the extraordinary challenges that have confronted the search for the lost Boeing 777 at nearly every turn. The jet, with 239 people aboard, disappeared March 8 on a flight from Kuala Lumpur, Malaysia's capital city, to Beijing, China. It is presumed to have crashed off Australia's west coast.

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The Artemis Bluefin-21 AUV is hoisted back onboard the Ocean Shield after a successful buoyancy test in the southern Indian Ocean on April 4, 2014.

Mini-Sub Is Latest High-Tech Tool to Join the Search

Artemis is only the latest high-tech tool to be deployed in what is now the longest search in aviation history. The sub is a Bluefin-21, one of a class of sophisticated autonomous underwater vehicles (AUVs) that operate worldwide, performing tasks that include finding lost planes and sunken ships, surveying offshore subsea mining sites, mapping underwater archeological finds, and rescuing submarines.

The vehicle was first developed by a team of engineers at MIT's Sea Grant lab; the team later founded Bluefin Robotics, based in Quincy, Massachusetts. CEO David Kelly says the company has manufactured about a hundred Bluefins, which come in three different models and cost $4 to $6 million apiece.

The Bluefins' small size enables them to be easily shipped. The Bluefin-21, the largest model, is just 21 inches (53 centimeters) in diameter and resembles a torpedo.

Bluefin AUVs differ from the better known remotely operated vehicles (ROVs) in two important ways. ROVs explored the Titanic and retrieved the black boxes from Air France Flight 447, which crashed into the deep Atlantic in 2009. ROVs are tethered to a mother surface ship, which limits their range, and shipboard technicians control them. AUVs, in contrast, roam freely and operate independently, without control from above.

"You don't need a ship dedicated to it in order to mobilize it," Kelly says.

But ROVs are capable of also plucking items off the ocean floor—a capability that Bluefins lack.

Artemis got its name, Gibson says, because the sub is the hunting companion of "Orion," the Navy's towed search system, named for the greatest hunter in Greek mythology. Before being shipped to Australia to join the search, which now involves ships and planes from eight nations, Artemis helped find a U.S. Air Force F-15 that had crashed off Okinawa, Japan, and was involved in the search for Amelia Earhart's plane.

Each dive in the search for the missing Malaysian plane takes 24 hours. Artemis takes 2.5 hours to descend, 1.5 hours to return to the surface, and 4 hours to download its data, Gibson says. The sub can remain below for 16 hours, mapping terrain using side-scan sonar, which uses acoustic technology to create 3-D images from sound, instead of light.

To capture the images, Artemis ambles along, about 150 feet (46 meters) above the ocean floor, methodically covering parallel rows that are often referred to as "mowing the lawn." The sub can cover 15 square miles (39 square kilometers) a day.

First Dive Aborted After Six Hours

Artemis's first mission on Monday was "a very good first dive," Gibson says. The sub was deployed from an Australian military ship named Ocean Shield, descended 3 miles (4.8 kilometers) without incident, and recorded data from the ocean bottom.

The sub followed the ocean floor, as programmed. When the floor dropped below 3 miles, the sub's built-in safety feature aborted the mission.

Artemis's technical crew above had programmed into the mission a pair of backup dives, so as the sub began to return to the surface, the technicians instructed it to begin the next dive.

"It tried, but that area was too deep, also," Gibson says. The mission ended.

Artemis collected, Gibson says, two lines of "good quality" side-scan data. Each was about 4 miles (6.4 kilometers) long and 1 mile (1.6 kilometers) wide. No wreckage was spotted.