The Australian head of the search for missing Malaysia Airlines flight MH370 announced on Monday morning that they would deploy a Bluefin 21 autonomous submarine to search for the wreckage.

Crews have been combing a relatively small (though large in sheer volume) section of the Indian Ocean for the last week, trying to pinpoint the location of pings that are believed to have originated from the plane’s black box. The search crews have not picked up any sounds for six days, and the box’s battery has a shelf life of 30 days. It is now day 38 of the search.

At a press conference this morning, Angus Houston, leader of the Australian search effort, said:

Analysis of the four signals has allowed the provisional definition of a reduced and manageable search area on the ocean floor. The experts have therefore determined that the Australian Defense Vessel Ocean Shield will cease searching with the towed pinger locator later today and deploy the autonomous underwater vehicle Bluefin 21 as soon as possible.

The Bluefin 21 will be deployed on several 24-hour missions to create sonar maps of the ocean floor. It takes 2 hours to dive, 16 hours to navigate along the ocean floor, another 2 to surface, and finally another 4 to download and analyze the collected data. The size of the autonomous underwater vehicle’s search area is about 230 square miles.

As is the norm, Houston stressed that the new search strategy may still not turn up any useful information.