An object floats in the southern Indian Ocean in this picture taken from a Royal New Zealand Air Force P-3K2 Orion aircraft searching for missing Malaysia Airlines Flight 370. A day after the search for the Malaysian jetliner shifted to a new area of the Indian Ocean, ships on Saturday plucked objects from the sea to determine whether they were related to the missing jet. None were confirmed to be from the plane.

March 29, 2014 An object floats in the southern Indian Ocean in this picture taken from a Royal New Zealand Air Force P-3K2 Orion aircraft searching for missing Malaysia Airlines Flight 370. A day after the search for the Malaysian jetliner shifted to a new area of the Indian Ocean, ships on Saturday plucked objects from the sea to determine whether they were related to the missing jet. None were confirmed to be from the plane. Pool photo by Jason Reed/via AP

Observers on a Chinese plane scouring the Indian Ocean for signs of Malaysia Airlines Flight 370 spotted three floating items in the water Saturday, but determining whether the debris is related to the missing plane will have to wait until ships relocate the items and dredge them up to examine more closely.

New satellite images taken this week show more than 100 objects — some as long as 75 feet — that may have come from the missing Malaysia Airlines jet.

New satellite images taken this week show more than 100 objects — some as long as 75 feet — that may have come from the missing Malaysia Airlines jet.

Brandon Yaeger sees something in the distance, glistening on the surface of the Indian Ocean. He can’t tell what it is. It could be nothing significant. Or it could be what’s left of Flight 370.

Yaeger is a 21-year-old U.S. Navy aircrewman, flying 1,000 feet above the sea in a P-3 Orion, a surveillance aircraft. His job is to look out the porthole for debris from the missing Malaysia Airlines jet. He races to the front of the plane and tells his superiors that something is out there.

The Orion banks and descends to 500 feet above water. A video camera sits under the plane’s nose. It sends high-resolution images to the crew members’ computer monitors. They realize what is down there: plastic bags and twine, tangled in seaweed.

So the search continues. And continues. It is a search of extraordinary scope, truly a global enterprise, with elements at sea, in the air and in space, and encompassing investigatory agencies from Washington to London to Kuala Lumpur. At least 30 nations have participated. But as of Sunday, the plane still had not materialized.

The primary search area keeps moving — and Friday it moved again, lurching 700 miles to the northeast off the western coast of Australia. For the families of the 239 people on the missing jet, the constant twists and turns are agonizing.

View Graphic The international effort to locate Flight 370

For the searchers, this has been a struggle marked by an occasional breakthrough and repeated false leads and dashed hopes. It has proceeded on several tracks. One involves about 140 ships and planes that have scoured sea and land. Another includes scientists and engineers probing ambiguous radio signals, trying to find meaning in the noise and somehow define the area where the plane could have flown.

This report is a look at the searchers’ race against time, glimpsed through the efforts of a young U.S. Navy aircrew flying out of Malaysia and a group of engineers, mathematicians and astrophysicists working more than 6,000 miles away, at the London headquarters of the satellite firm Inmarsat.

“Every time we see something, we all get excited,” said Lt. Chris Kovach, 31, from Berwick, Pa., one of the pilots on the Orion. But on a recent afternoon, it was clear that the lack of results had taken a toll.

“It does get discouraging, because we want to help the families get closure,” he said.

The South China Sea

On Saturday, March 8, the Orion’s 11 crew members were on standby duty at their base on the Japanese island of Okinawa. At 8 p.m., they were told to get ready. A passenger jet en route from Kuala Lumpur to Beijing had disappeared northeast of the Malaysian peninsula early that morning.

Within a few hours, the Orion crew — known as Naval Patrol Squadron (VP) 46, or the Grey Knights — was in the air. The Orion carried life rafts equipped with food, water and flares to drop to potential survivors. By that afternoon, on March 9, they were over the South China Sea northeast of the Malaysian peninsula, searching the waters.

Yaeger, from Gunnison, Utah, population 3,300, was excited to be part of the growing search-and-rescue operation. His great-grandfather fought in World War II, his grandfather saw combat in Korea, and his father had helped guard NATO’s nuclear warheads in Germany.

Australia's prime minister says there will be no time limit on the search for the missing Malaysia Airlines plane. Twenty aircraft and ships are scouring the seas off the Australian south-west coast on Monday. (Reuters)

“It is awesome to do something in a real-world scenario, where I can make a difference,” he later said.

Potomac, Md.

That same Sunday, sitting at his kitchen table in Potomac, Md., John Mackey started to realize the enormousness of the unfolding mystery. He runs network operations for Inmarsat and shuttles between its offices in London and Washington.

As the 47-year-old engineer drank his coffee and ate a bagel, he scrolled through the e-mails on his smartphone. One was from the company’s ground satellite station in Australia. A technician had captured some data from a Malaysian flight.

Then Mackey read the news about Flight 370.

Something didn’t make sense: The Malaysia Airlines plane had vanished from civilian radar at 1:21 a.m. Saturday, but the data showed that the aircraft was still communicating with the satellite well after it was due in Beijing five hours later.

Where on earth was the plane?

“I just started to think about all the people who were on that plane and what might have happened,” Mackey said. “It was just terrible.”

The Malacca Strait

Back in Kuala Lumpur that day, Malaysia’s air force chief, Gen. Rodzali Daud, said at a news conference that a puzzling piece of information had emerged from military radar. The Malaysia Airlines plane “may have made a turn back,” Rodzali said. He gave no details.

Authorities redirected some ships and planes to the seas between the west coast of Malaysia and eastern Indonesia. But days passed before authorities finally revealed what their military had found: There had been a radar blip at 2:14 a.m. Saturday in the Malacca Strait, off the Malaysian peninsula’s northwest coast. The plane probably wasn’t in the South China Sea after all.

Some countries were upset at Malaysia’s chaotic and contradictory release of information. But morale was high among the Grey Knights. They followed their orders to shift to the new search zone, which gradually expanded west into the Indian Ocean.

Yaeger normally works as an acoustic operator, trained to don headphones and listen for the sound of submarines. For this mission, though, he was using his eyes, surveying the ocean, back and forth.

In the cockpit, pilot Kovach was doing the same thing. The constant scanning messes with your mind a bit, he would later tell a reporter.

“Sometimes you see something — your mind starts fabricating stuff,” he said.

London, March 11

At Inmarsat’s black-glass headquarters in London’s “Silicon Roundabout,” a hub of high-tech companies, there was suddenly a breakthrough.

Four teams had been working day after day, sketching out calculations on whiteboards, studying Google Earth maps and clicking through Excel spreadsheets to try to interpret their satellite data.

The main communication systems on the Malaysia Airlines plane had been turned off or disabled during the flight. But the jet had something called Classic Aero, which sent an hourly “handshake” to a ground-based radio antenna, via Inmarsat Satellite 3F1 above the Indian Ocean. There were six “handshakes” after the plane disappeared.

Each transmission was just a burst of radio waves. It didn’t show where the plane was.

But Tuesday morning, March 11, one of the Inmarsat teams approached Ruy Pinto, a Brazilian-born scientist who is the company’s chief operations officer. The team members thought that if they made certain assumptions about the plane’s speed and direction, they could map out a north-south corridor the plane may had traveled along.

“They immediately recognized the importance of what they had found,” Pinto later recalled.

That day, Inmarsat passed the information to Malaysia Airlines’ information management firm, Sita. Four days later, Prime Minister Najib Razak announced that the search area had shifted again — to two vast curving swaths of territory, one stretching north from Thailand to Kazakhstan, the other south into the Indian Ocean.

London, March 21

The initial Inmarsat analysis of the satellite “handshake” set up a deeper dive into this thin stream of information. The search area now encompassed 3 million square miles of land and sea, roughly the size of the contiguous United States. How could it be narrowed?

It was a question that obsessed the scientists, engineers and investigators involved in the search. They came from U.S. and British government aviation agencies, as well as private companies such as Rolls-Royce — which made the jet’s engine — and Boeing, the plane’s manufacturer. Australian government experts pitched in on calculations that shrank the search field off that country’s coast to 230,000 square miles.

For nearly two weeks, the Inmarsat engineers and scientists had been puzzling over the data. They would have rushes of adrenaline but also felt trepidation at the vastness of the task.

Finally, on Friday, March 21, they had an “aha moment.” They had been looking for minor changes in the “handshake” signals — a shift in the wavelength caused by an object moving away, known as the Doppler effect.

They realized that the plane could not have traveled along the northern corridor. They created two possible flight paths in the southern corridor, assuming different speeds, and came up with two potential locations far to the west of Australia in the southern Indian Ocean.

“We are supposed to be dispassionate scientists,” Pinto, 54, said. “We’ve never been in a situation like this before. We didn’t want to go on any wild-goose chases. We didn’t want to waste any time, and we didn’t want to be wrong.”

For days, Inmarsat had been bombarded by e-mails from around the world criticizing the investigation and insisting that the firm share its data with other scientists. But the Inmarsat teams were part of an ongoing investigation. They were not permitted by British officials to publicly release their data, company officials said.

That Friday afternoon, Christopher McLaughlin, Inmarsat’s senior vice president, stepped away from the office. He knew more bad news was about to break; a crash in the remote southern Indian Ocean would almost certainly have left no survivors. His wife and 3-year-old son, Lucas, would soon be boarding a Boeing 777 bound for Australia to see the child’s grandparents. He took his son to Wimbledon Common, a park, for a father-son ad­ven­ture, a make-believe hunt for foxes and other animals hiding in the brambles.

The park is in the flight path of London Heathrow Airport. Plane after plane slid across the sky.

“I just started to think about all those families and what they were about to find out, and I was watching my son playing with his stick, looking for foxes,” McLaughlin said. “I just felt so lucky, hugely privileged.”

Two days later, on Sunday, March 23, the Inmarsat scientists shared their findings with members of the international investigative team and an outside scientist. Everyone agreed. Flight 370 had ended in the southern Indian Ocean.

The Indian Ocean

The next day, Monday, March 24, the Grey Knights got their latest search assignment from the Malaysian authorities. It was in the Indian Ocean. But it was west of Indonesia — nowhere near Australia.

During their flight, Yaeger spotted the plastic bags. The radar picked up fishing trawlers, a tanker, and, at one point, a faint blip seven miles away. That turned out to be a pod of dolphins, breaking the surface of the glassy sea.

If the crew members knew they were on a wild-goose chase, they didn’t show it.

“Everyone is motivated to make a difference — we have been here since Day One. We really want to help these families,” said Chief Warrant Officer Jorge Guilloty, 34, from Puerto Rico.

At about 9:45 p.m., the Grey Knights arrived back at the Subang military air base in Kuala Lumpur. Minutes later, a grim-faced Najib, the Malaysian prime minister, appeared before a hastily summoned news conference. Based on the latest calculations, he said, “Flight MH370 ended in the southern Indian Ocean.”

Australia

On Friday, March 28, the U.S. Navy announced that the Grey Knights would be returning to Okinawa. They had covered more than 145,000 square miles of search area. The same day, authorities announced that the search zone had moved again — to a different part of the Indian Ocean, closer to Australia. That was based on still more calculations, using the latest Inmarsat models and the military radar data captured March 8.

In Australia, Prime Minister Tony Abbott counseled patience.

“We are trying to find small bits of wreckage in a vast ocean,” he said.

Three weeks had passed since the start of an unprecedented global aviation hunt, and no one had found any wreckage from Flight 370. The batteries on the plane’s cockpit recorder will go dead in a matter of days.

Higham reported from London. Jia-Lynn Yang in Kuala Lumpur, Chico Harlan in Seoul, Annie Gowen in New Delhi and Joel Achenbach and Ashley Halsey III in Washington contributed to this report.