Quest to solve the Amelia Earhart mystery

Famed aviator Amelia Earhart is seen here in 1932. On Jan. 11, 1935, Earhart became the first person to fly solo across the Pacific, traveling from Honolulu to Oakland, Calif. In her subsequent quest to become the first woman to traverse the globe, she vanished forever -- a historical question mark that has stood for 75 years.

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In this 1932 photo, Earhart and Bernt Balchen pose at Teterboro Airport in New Jersey before a flight to Newfoundland.

Credit: AP Photo, file

On July 3, 2012, a day after the 75th anniversary of Earhart's disappearance, The International Group for Historic Aircraft Recovery (TIGAR) launched a high-tech deep water expedition - Niku VII - to search for her aircraft, the Earhart Electra, in the waters adjacent to Nikumaroro in the Republic of Kiribati.

In this 1937 photo, Earhart stands with a Lockheed Electra 10E aircraft in Oakland, Calif.

Credit: AP Photo, file

On June 1, 1937, Earhart and her navigator, Fred Noonan, departed from Miami and began the 29,000-mile journey. By June 29, when they landed in Lae, New Guinea, all but 7,000 miles of the planned route had been completed. The final radio transmission came through on July 2, 1937: "We are running north and south." Earhart and Noonan were never heard from again.

A rescue attempt commenced immediately and became what was then the most extensive air and sea search in naval history. On July 19, 1937, after spending $4 million and scouring 250,000 square miles of ocean, the U.S. government called off the operation. Earhart is seen here in this undated file photo.

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Earhart poses with technical adviser Paul Mantz, left, and navigators Harry Manning and Fred Noonan, in 1937.

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Extensive searches for Earhart, seen here in 1937, and Noonan uncovered no clues at the time of her disappearance.

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Amelia Earhart and her navigator Fred Noonan are captured in this photo before leaving on what was to be their final flight.

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In this 1937 photo, Earhart and her navigator, Fred Noonan, pose in Natal, Brazil, on a stopover during their globe-circling flight.

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Earhart's Lockheed Electra aircraft is seen in 1937 in Wheeler Field, Hawaii, prior to its departure for Howland Island.

Credit: AP Photo, file

Having failed to find their next destination on the journey, Howland Island, Earhart and Noonan continued on the navigational line Earhart said they were following when they last communicated with their radio contact.

Following that line, researchers now believe the uninhabited Gardner Island, now known as Nikumaroro and seen here, may be the location where Earhart landed the Electra safely on the island

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Shown here is the U.S. Coast Cuard cutter Itasca, which was the last ship to be in radio contact with Earhart's plane before it vanished.

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Earhart is seen here in this undated photo.

Credit: AP Photo, file

Using sonar technology, TIGHAR's research vessel, Ka'Imikai-O-Kanaloa (meaning heavenly searcher of the seas) planned to set out on the long-awaited search for Earhart's Lockheed Electra in the deep waters off the reef at Nikumaroro. The location of the search area is seen here.

Credit: TIGHAR

The search area will be mapped using "multi-beam sonar hull-mounted on the expedition vessel," supplemented in shallower areas by multi-beam sonar mounted on the autonomous underwater vehicle (AUV) seen here, according to TIGHAR.

Credit: TIGHAR

Once the AUV has concluded its coverage of the search area, the collected sonar data have been analyzed, and a list of targets of interest have been compiled, a remote operated vehicle (ROV) will be deployed to further investigate the targets. Tethered to the expedition vessel, the ROV is directed to the desired locations by an operator aboard the expedition vessel.

The ROV is equipped with sector-scan sonar to help re-locate the target. It has powerful lights and high-definition video cameras to provide real-time imagery to the operator, along with a manipulator arm which can be used to remove obscuring objects, TIGHAR explained.

Credit: TIGHAR

The primary search area is based upon the hypothesis that the aircraft landed safely on the reef and remained there for several days before being washed away. This 1937 photo taken by Navy Cadet Officer Eric Bevington appears to show a detached landing gear assembly.

Credit: TIGHAR

Photo analysts at the U.S. State Department

Credit: TIGHAR

This bottle, an apparent container of Campana Italian Balm popular for American women back in the 1930s, was found near the remote island of Nikumaroro and suggests that Earhart may have been there, researchers say. Other artifacts found include bits of rouge and a mirror believed to be from a woman

Credit: TIGHAR

Earhart is seen here in this undated photo.

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A bottle of Campana Italian Balm, the company

Credit: TIGHAR

In this 1932 photo, Earhart boards a Lockheed Vega single-engine plane in Londonderry, Northern Ireland, for trip back to London after solo nonstop Atlantic crossing.

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Tests of a bone fragment that could have been from Earhart

Credit: TIGHAR

Earhart is seen here in this undated photo.

Credit: AP Photo, file