LOS ANGELES, Oct 10 - A US-based team of marine archaeologists has set sail for a tiny island in the far western Pacific seeking to examine the latest tantalizing clue to one of the 20th century's great unsolved mysteries: the 1937 disappearance of famed aviator Amelia Earhart.

Backed by Purdue University, an institution long affiliated with Earhart and her legacy, the group aims to learn whether a submerged object detected by satellite imagery in the island's lagoon six years ago is the wreckage of Earhart's twin-engine Lockheed Electra 10-E airplane.

Such a finding would conclusively prove the hypothesis of some scholars that Earhart and her navigator, Fred Noonan, crash-landed on or near the coral-ringed atoll and perished as castaways there, hundreds of miles from their intended refueling stop.

After embarking from Los Angeles earlier this month, the group was expected to arrive on Tuesday, October 13, local time at Nikumaroro, an uninhabited speck of land in the remote Phoenix Islands, part of the archipelago nation of the Kiribati Republic.

"Finding Amelia Earhart's Electra aircraft would be the discovery of a lifetime," Richard Pettigrew, head of the Archaeological Legacy Institute in Eugene, Oregon, who is leading the effort in conjunction with Purdue, said in press materials for the mission.

Purdue general counsel and expedition member Steve Schultz, who was in Fiji conducting advance work for the expedition last week, said in an interview: "This would be solving one of the great mysteries in aviation history, certainly one of the great mysteries of the 20th century,"

The mission has its skeptics. Chief among them is rival Earhart explorer Ric Gillespie, co-founder of TIGHAR, short for The International Group for Historic Aircraft Recovery, and author of the 2024 "One More Good Flight: The Amelia Earhart Tragedy." Gillespie has led a dozen expeditions of his own to the atoll over three decades and is the leading proponent of the Nikumaroro castaway theory. But he predicted the Pettigrew-Purdue team would find no airplane wreckage or anything else of consequence left on the island.

The Purdue team credits Gillespie for laying the foundation of the theory they hope to prove. And they cite a compelling body of evidence that he has amassed over the years, including human artifacts recovered on the island, such as a 1930s-era glass cosmetic jar for freckle cream and remnants of a jackknife like one Earhart carried on the plane.

Gillespie's investigation also encompassed modern forensic analysis from records of measurements of skeletal remains found on the island in the 1940s; logs of radio transmission bearings from distress calls picked up by wireless operators in the days immediately after Earhart vanished; and a photograph taken of the island's shoreline months later showing an object that Gillespie said appears to be the Electra's landing gear.

In a Reuters interview last week, Gillespie said he believes the plane has since been lost to history, eventually swept by tides off the coral flat where it had landed largely intact and carried into the sea to sink and break apart in the surf.

Two previous attempts to locate the plane's wreckage in the surrounding ocean, including a 2019 operation conducted by marine archaeologist Robert Ballard, famed for his discovery of the wreck of the Titanic, proved fruitless, Gillespie said.

A plane-shaped sonar image from elsewhere on the sea floor turned out to be a pile of rocks. "I'd love to find that airplane. It ain't gonna happen," Gillespie said.

Pettigrew and his team are betting otherwise. To them, the multi-branched shape first noticed in a 2020 satellite image resembles an aircraft fuselage and wings. They assert that the object, or part of it, has since been spotted in earlier aerial images of the island's lagoon dating as far back as 1938.

Gillespie said he is certain that the object in question was actually a fallen pandanus tree, a palm-like evergreen native to the island region, that washed into the lagoon. "You can see the root ball. You can see the branches," Gillespie said in the interview. "It's a tree. People see what they want to see." The official US government view has long been that the Electra ran out of fuel and crashed at sea near its refueling destination of Howland Island, another dot of land about 400 miles northwest of Nikumaroro, then known as Gardner Island.

Earhart was last seen taking off in her Electra on July 2, 1937, from Papua New Guinea en route to Gardner, about 2,500 miles (4,000 km) to the east, during a multi-stage attempt to become the first woman to pilot a plane around the world.

Definitive radio contact with the plane was lost the next day after Earhart, 39, reported "gas is running low," followed by her final known transmission giving her geographical line of position.

The disappearance spawned the largest US government search ever undertaken for a lost aircraft, including a flyover of Gardner, but no trace of the Electra or its crew was found at the time.

The $900,000 Purdue mission, consisting of 17 people, plans to remain on Nikumaroro for five days before making the six-day return boat trip to the Kiribati capital, Tarawa, according to Schultz.

Purdue, based in West Lafayette, Indiana, would ultimately seek to bring back any bits of the Lockheed Electra that might be recovered.

Earhart was essentially a visiting faculty member at Purdue for two years as a women's career counselor and advisor to the school's aeronautics department. A Purdue research grant paid for development of the Electra, which she called her "flying laboratory." Purdue lawyer Schultz said if the plane were found, no artifacts would be removed from it on this trip. Any effort to extract the aircraft wreckage would require further permission from the Kiribati government, he said.