May 1: National Geographic Midway Expedition launches from Midway Island in the Pacific. Mission: To find, map, photograph and explore the lost ships of the Battle of Midway.

May 2: The search begins. At 7:30 a.m. the University of Hawaii’s MR-1 sonar vehicle is launched. Bob Ballard and crew look for any odd feature picked up by sonar that may indicate the resting place of the U.S.S. Yorktown, the U.S. Navy aircraft carrier lost in the World War II Battle of Midway between the U.S. and Japan.

May 3: The Laney Chouest, the U.S. Navy ship towing the MR-1 tracking vehicle and serving as the base of the expedition, goes back and forth across the search area in a lawn-mowing pattern. The MR-1 has become the heart of the search. At least one member of the crew is watching the computer monitors at any given moment, scanning the sonar images of the ocean floor or sifting the data for clues. The sonar signals are marked as lines on the undersea charts.

May 5: Today Ballard decides on a new strategy to locate the Yorktown. He sends the U.S. Navy’s Advanced Tethered Vehicle (ATV), a sophisticated new device able to explore at great depths, to look for the destroyer U.S.S. Hammann. The Hammann was sunk by Japanese torpedoes in the same general area as the Yorktown. The Hammann broke in two and sank quickly. Ballard believes its wreckage will point to the Yorktown.

May 6: The ATV is launched. The epoxy that binds the tether to the ATV cracks, resulting in a loss of power to the ATV. The Navy team repairs it while Ballard and others study the underwater charts for signs of a “target”—a likely site of the Yorktown. Ballard and others identify what they believe to be a target and plan to send the ATV down May 7 to investigate.

May 7: The ATV is launched again. Undefined problems at 5,000 feet (1,524 meters); the crew decides to bring it back to the surface for inspection.

May 8: Problems corrected. The ATV goes down again and this time at about 15,500 feet (4,724 meters) another problem is indicated. It returns to the surface to reveal that an implosion has occurred, causing considerable damage to the vehicle. The ATV is out of commission until repairs can be made. The Laney Chouest now uses the MR-1 to search for the sunken Japanese aircraft carriers.

May 10: The ATV is repaired and sent back to the sea bottom to inspect what Ballard thinks is the wreckage of the Japanese carrier Kaga.

May 11: The ATV arrives on the floor after a long descent and inspects the object that is hoped to be the Kaga. It turns out to be nothing of importance. Ballard now directs the ATV across the battle site of Midway to the next target, a potential site of the Japanese carrier Akagi.

May 12: Give up searching for the Kaga and the Akagi and resume the search for the Yorktown.

May 15: Stop at Midway Island to drop off and pick up passengers, take on supplies and continue repairs to the ATV. Underwater photographer David Doubilet comes on board for what Ballard calls “the documentation phase.”

ATV lights destroyed in the implosion have to be replaced with a system capable of operating at a depth of nearly 17,000 feet (5,182 meters). A system is borrowed from another expedition that will be featured in a future National Geographic Television production.

May 17: Twice the ATV begins its descent and twice it has to be hauled back up because of new damage. Examination and repairs made.

May 19: The Yorktown is found! It is identified by Ballard with help from Battle of Midway Yorktown survivor Bill Surgi, who has been on board for the entire expedition.

May 20-25: Mapping, exploration, photographing of the Yorktown. Further searching for the Hammann.

May 24: The Navy’s ATV revisted the Yorktown site and delivered a bronze plaque that reads: “YORKTOWN. Gallant ship whose planes, operating against great odds and at large sacrifice, played a decisive role in destroying two of the four carriers of the Japanese Combined Fleet in the Battle of Midway and thus turned the tide toward victory in the war against Japan. Mortally wounded by aircraft bombs and torpedoes on June 4, 1942, she sank on June 7, 1942 at 0458.” The plaque was supplied by the International Midway Memorial Foundation.

May 26: National Geographic Midway Expedition returns to port.

#