This mission, which set off from Fiji on Saturday, is a collaboration between National Geographic, the tour company Betchart Expeditions and The International Group for Historic Aircraft Recovery, a nonprofit organization based in Pennsylvania. It is better known by its acronym Tighar, which is pronounced “tiger.”
Tighar has been at this for decades. This will be its 12th expedition to Nikumaroro.
“It’s been a long process. It’s like building a jigsaw puzzle,” said Ric Gillespie, the organization’s executive director. He sees his past 11 trips not as a string of failures, but as a slow and steady accumulation of evidence that will lead him, one day, to the smoking gun he’s looking for.
National Geographic has sponsored the four forensic canines — Berkeley, Piper, Marcy and Kayle, all Border collies — but it would not share details about the cost of this week’s expedition. Mr. Gillespie said that Tighar’s own expeditions in past years, which were funded mostly through member contributions, have cost anywhere from $500,000 to around $2 million.
Andrew McKenna, a diver who is a member of Tighar, said in a phone interview from Fiji last week that he would be looking for the Electra at sea, while the dogs do their work on land.
Their stay on the remote atoll of Nikumaroro will last for eight days, he said. And even though the island is very hot, covered in thick vegetation and populated by massive coconut crabs, he was already wishing for more time. “Frankly,” he said, “you always leave just when you were beginning to feel productive.”
According to Tighar’s hypothesis, Ms. Earhart and Mr. Noonan veered south of their planned flight path and landed on Nikumaroro (then referred to as Gardner Island). They sent out distress signals using power from the Electra’s engine, until a high tide washed the plane away. Navy planes then flew over the island in their search for the Electra and, not seeing it, passed by.
“The drama really is in that moment,” Mr. McKenna said. “You just imagine Amelia waving her arms frantically at the airplanes overhead, and then they fly away, and she’s literally marooned. What do you do then?”
But not everyone agrees with that version of events.
Some have argued in support of more outlandish ideas, claiming that Ms. Earhart was a spy who was captured by Japanese operatives. There was also a theory that she somehow made her way back to the United States and lived a long, quiet life under a different name in New Jersey.
But historically, the most widely accepted idea has been the so-called crash-and-sink theory — the one originally endorsed by the U.S. government — which holds that Ms. Earhart’s plane plunged straight into the ocean.
The incompatibility between the Nikumaroro narrative and the crash-and-sink hypothesis sparked a decades-long rivalry between opposing teams of researchers and historians. Books and articles have been written, harsh words have been exchanged, and expensive expeditions have been launched in support of both major theories.
“They just want to believe it so desperately, that we can find her,” said Dorothy Cochrane, a curator in the aeronautics department at the Smithsonian National Air and Space Museum. “I hope we find her some day, but it’s not that important to me. What’s important to me is her legacy.”
Ms. Cochrane said she believes with near-certainty that Ms. Earhart never reached Nikumaroro.
But the people of Tighar say the evidence is stacked in their favor. They point to artifacts found on the island: an American-made zipper, shards of American-made bottles, and pieces of a jar matching the ones used by an American freckle ointment company during the 1930s.
Ms. Cochrane said those could have been left by British colonists or others who arrived on the atoll after Ms. Earhart’s disappearance.
Mr. Gillespie said there are various other hints in support of his theory, citing documents of radio transmissions, records of bones found on the island, an old photo that appeared to show the Electra poking out of the water near the atoll in 1937, and more. It’s all been carefully documented on the Tighar website.
But evidence, he said, is not proof.
“What the public wants is a smoking gun,” he said, adding that if the Electra can’t be found, “they want a bone with D.N.A. that matches Earhart’s D.N.A.”
That is what the dogs are for.
Fredrik Hiebert, the archaeologist-in-residence for the National Geographic Society who is on the expedition, said he’d been intrigued by the idea of forensic canines for years.
“They’re alerting for the decomposition chemical that happens as the human body and bones decompose, and this chemical is very unique,” he said.
Still, Mr. Gillespie has his doubts as to whether these dogs would be able to uncover usable D.N.A. samples after 80 years.
And his critics have doubts as to whether Ms. Earhart ever made it to the atoll at all.