WASHINGTON/LONDON An unprecedented international effort is under way from space to track the missing Malaysia passenger jet as satellite operators, government agencies and rival nations sweep their gaze across two oceans in search of elusive debris or data.
Six days after the Malaysia Airlines MASM.KL Boeing 777 went missing with 239 people on board, the search has widened to the Andaman Sea, northwest of the Malay Peninsula, with only one precious clue - an ephemeral 'ping' detected five or six times after the plane lost contact - picked up in orbit.
Disaster relief agencies and governments are co-operating across political divides, and in the absence of a formal probe are finding informal ways to share information, including via China's weather agency, a person involved in the search said.
"I haven't seen this sort of level of involvement of satellites in accident investigation before," said Matthew Greaves, head of the Safety and Accident Investigation Centre at Cranfield University in Bedford, England. "It is only going to get more important until they find some wreckage."
Several governments are using imagery satellites - platforms that take high definition photos - while data from private sector communications satellites is also being examined.
China alone says it has deployed 10 satellites in the search in a pointed reminder of its growing influence in space. The United States is using all the capabilities that have a view of the area in question, including very high-resolution electro-optical satellites that can identify a car's license plate from space, U.S. government officials said.
"There are a lot of satellites looking at that area of the world," said one source familiar with the network of U.S. national security satellites.
"NEEDLE IN A HAYSTACK"
But having conquered space, orbital nations have been rendered helpless by the sheer scale of the task back on earth.
"It is like finding a needle in a haystack and the area is enormous. Finding anything rapidly is going to be very difficult," said Marc Pircher, director of the French space centre in Toulouse, run by the country's CNES space agency.
"The area and scale of the task is such that 99 percent of what you are getting are false alarms".
With no firm evidence about where the plane was heading, whether or where it crashed or if it landed, authorities have yet to launch an official probe. Until those questions are answered, it remains uncertain which country would be responsible for such an investigation.
Even so, sources close to the informal investigation encompassing the world's leading space-faring nations as well as naval and air assets said on Thursday a brief "ping" sent hourly five or six times had been received by one or more satellites.
As they try to wring more information out of these faint carrier signals, experts will need to analyse the exact time of transmission and the strength of the signal. The number of satellites spotting the faint electronic blink will be crucial.
"If you have three or more data points, it should be relatively easy to triangulate where the aircraft is and the direction in which it is going in," said Elizabeth Quintana, Director of Military Sciences at the Royal United services Institute.
"However, the sheer number of aircraft operating in the area may make it difficult to pinpoint where the signal was coming from."
Satellite experts say the process of triangulation used to pinpoint the whereabouts of mobile phones might help narrow down the search, but would not be nearly as accurate as navigational results from the Global Positioning System.
"It will not be easy to find the position exactly because these are telecommunications satellites, not position-locating satellites," said Pircher. "To track positions by triangulation you need extremely accurate computer clocks."
Most aircraft are equipped to send and receive automatic text messages on any glitches to the airline via radio or satellite links, using either the medium-orbit Iridium (IRDM.O) constellation or the higher, geostationary satellites operated by Britain's Inmarsat (ISA.L).
Certain single satellites can also detect a position from, say, a distress beacon by taking advantage of the Doppler effect. But this is not available on either network used by the airline industry to handle fleet communications, Pircher said.
One industry source said it was possible to figure out the location of a ship or plane that is the source of a "ping" by calculating the distance from the satellite to the item and the angle of elevation. The source said that such information about Flight 370 could become available in the next few days.
Another U.S. government source did not rule out presence of some garbled data from the "ping."
DIFFICULT TASK AT BEST
Canada, France, Russia and the United States are also co-operating through in a satellite-based search and rescue venture called COSPAS-SARSAT, an official involved in the work said.
Inmarsat, whose systems were on the aircraft, said "routine, automated signals" were seen on its network during its flight from Kuala Lumpur, but Malaysian officials said none of them came after the Boeing 777 vanished.
Iridium said the "pings" from the aircraft were not handled by its satellites.
People close to the investigation into the disappearance of Flight 370 acknowledge gleaning clues from the plane's flight path and whereabouts from satellite data can prove to be a difficult task.
In at least two instances so far, officials thought they had run across satellite imagery that might have pointed to the location of wreckage from the 777 off the east coast of Malaysia, only for the information to be discredited.
A complete veil has been drawn over what co-operation, if any, has been provided by military or high-powered satellites.
The jet vanished in an area of regional sensitivities not far from the South China Sea and near the Malacca Strait, where the region's main actors have historically disputed over island ownership and maritime boundaries.
"It is possible governments have satellites looking, of course," Greaves said. "The question is, will we get to a point were people will come under pressure to come forward."
High-end electro-optical satellites may in any case be of limited use when so little is known about the jet's whereabouts because they are designed to look at very small, precise areas.
"You are essentially looking through a soda straw at a given area. So you have to know where you're looking," a U.S. government source said.
(Additional reporting by Mark Hosenball and Peter Apps; Writing by Tim Hepher; Editing by Frank McGurty)