An expedition to test the theory that aviatrix Amelia Earhart survived the crash of her airplane 75 years ago and died a castaway on a desert island left Hawaii on Tuesday.

The University of Hawaii research ship left the Snug Harbor here without fanfare under somber, drizzling skies at the start of a 26-day trip, including eight days at sea each way to Kiribati, in the central Pacific.

Richard Gillespie, the leader the International Group for Historic Aircraft Recovery (TIGHAR) mission, said they would use technology not previously available to try to learn the fate of the pioneering aviator.

"We are demonstrating the newest methods to sift fact from myth -- skills everyone can use these days when we are bombarded by information, not knowing what is true," he told AFP shortly before setting off.

"We will not be coming up with a solution to the mystery right away when we get on scene eight days from now... but we will bring back to Honolulu images we can send to the experts to verify if we have found part of her aircraft."

The expedition is heading to Nikumaroro island in Kiribati to try to establish whether Earhart survived the apparent crash of her twin-engine Lockheed Electra aircraft.

Earhart was flying with navigator Fred Noonan during the final stage of an ambitious round-the-world flight along the equator at the time that her plane disappeared on July 2, 1937.

The holder of several aeronautical records -- including the first woman to cross the Atlantic by air -- Earhart had set off from New Guinea to refuel at Howland Island for a final long-distance hop to California.

In what turned out to be her final radio message, she declared she was unable to find Howland and that fuel was running low.

Several search-and-rescue missions ordered by then-president Franklin Roosevelt turned up no trace of Earhart or Noonan, who were eventually presumed dead at sea.

Conspiracy theories flourished, including one contending that Earhart was held by Japanese imperial forces as a spy. Another claimed she completed her flight, but changed her identity and settled in New Jersey.

Aircraft debris reportedly was found by island residents in subsequent years, but the TIGHAR research team is operating on the hypothesis that the aircraft landed safely on the reef and remained there for several days before being washed over the edge by rising tides and surf.

TIGHAR suspects that Earhart and Noonan reached Gardner Island -- at the time a British possession and now known as Nikumaroro -- and managed to survive for an unknown period of time.

The uninhabited coral atoll is a mere 3.7 miles (six kilometers) long by 1.2 miles (two kilometers) wide, and is about 300 miles (480 kilometers) southeast of Howland Island.

Gillespie believes the 39-year-old may have survived after her disappearance because of a series of clues -- including radio transmissions from the area, reportedly including a call for help, received at the time.

"Today, with computer software able to recreate the electromagnetic environment of 1937, we can do an analysis of the radio signals that were dismissed by authorities back then," Gillespie said.

"We find we are left with one of two possibilities: either she was on land in the Phoenix Islands group for six days sending radio distress messages -- or there was a hoaxer in that area who could transmit on that frequency, mimic her voice, knew personal details about her, and knew far enough in advance that he could set all these things up."

The expedition ship and a crew of about 20 scientists will spend 10 days on both the island and an underwater reef slope at its west end.

Technology on board includes a multi-beam sonar to map the ocean floor and a remote-controlled device similar to one that found the black boxes from the Rio-to-Paris Air France flight that crashed into the South Atlantic in 2009.

The search team is accompanied by a three-person camera crew who will film the expedition for a planned television special later this year.

[Image via Wikimedia Commons]