A robotic submarine was set to be launched on a second underwater sweep for wreckage from missing Flight MH370 Tuesday after deep water ended an initial dive, triggering questions about whether the vehicle is capable of completing its mission.
The U.S. Navy-owned Bluefin-21 gathered about six hours of data before returning to the surface of the southern Indian Ocean almost 1,000 miles off Australia's west coast.
Bluefin-21 can create a three-dimensional sonar map of the area to chart any debris on the sea floor. The initial data collected was analyzed but no objects of interest were found.
Searchers are confident they know the approximate position of wreckage of the Malaysia Airlines jet which vanished on March 8. They are moving ahead with the sub search on the basis of four acoustic signals they believe are from its black box recorders. However, no "pings" have been heard for almost a week.