The search for the missing Malaysia Airlines plane is focused in remote waters far southwest of Australia. The latest information on satellite images being investigated and how the search is being conducted:
THE SATELLITE IMAGES
Australian defence force experts assessed images taken by a commercial satellite of two main objects: one 24 metres long and the other 5 metres long. The objects are south of the area where searchers have been focusing in recent days.
The location is about 2,500 kilometres southwest of Perth in remote waters that often are stormy. Searchers caution the objects could be shipping debris or something else unrelated to the plane.
John Young, the manager of the Australia Maritime Safety Authority's emergency response division, said the images were relatively indistinct but credible sightings nonetheless. He said he thinks the objects are of a reasonable size and probably awash with water.
Peter Marosszeky, an aviation expert at the University of New South Wales in Sydney, said the objects could be some of the thousands of shipping containers that litter the ocean.
Australian authorities have redirected other commercial satellites to take higher resolution images, which might provide more clues.
THE PLANES
Four search planes and one transport plane from three countries flew to the site. Young said visibility was poor, which would hamper efforts. AMSA said clouds and rains obscured the view for at least one of its flights Thursday.
The search area is also far from land, so search co-ordinators have taken the approach of staggering the arrival of the planes.
Two Australian P-3 Orions and a New Zealand Orion made eight-hour round trips, allowing them only two hours to search before they had to return. They will resume searching on Friday.
Made by Lockheed Martin, the Orion was once used as a submarine finder but these days is more often used for maritime patrol. They were used to help in Hurricane Katrina and the BP Horizon oil rig disaster. Their sensors can detect objects at or below the water's surface.
The U.S. Navy sent a P-8 Poseidon airplane. It is adapted from a Boeing 737 commercial jet and is designed for long-range anti-submarine warfare as well as reconnaissance.
Australia's Air Force has also sent a C-130 Hercules, a military transport plane built by Lockheed. The purpose of the Hercules is to drop marker buoys in the area.
THE SHIPS
A Norwegian merchant ship that responded Monday to a request for help arrived in the search area Thursday evening and was expected to scan the area with radar overnight then start a visual search during the day Friday.
The Australian Navy has sent its own ship, the HMAS Success. The Success is the largest ship built for the navy and is large enough to recover any plane debris from the ocean if needed and transport it back. The naval ship is several days from the location.
Launched in 1984, the Success is 157 metres (515 feet) long with a displacement of 18,000 metric tons. It has a crew of 220 and comes complete with its own bakery and medical operating theatre.
THE BUOYS
The Hercules transport plane will drop marker buoys that float and drift with sea currents, theoretically mimicking the drift of any debris. Searchers then can track the buoys, which will be crucial if weather or other factors delay the search.
Marosszeky said the satellite images were cause for some hope in the search effort.
"But you've got to be careful," he said. "The ocean is full of debris."
