MercoPress. South Atlantic News Agency

Oceanographer's Antarctic Search for Shackleton's Endurance.

One of the world's most experienced underwater explorers, the United States Oceanographer, Dr Robert Ballard, who has discovered several famous wrecks, including the liner Titanic and the German battleship Bismarck, is preparing to embark on his toughest challenge yet -- a mission to locate the wreck of Sir Ernest Shackleton's Endurance. She sank in 1915 and has remained undetected ever since beneath the Antarctic pack ice.

Dr Ballard's 1.4 million pound (2.25 million dollar) mission is planned to set off from Punta Arenas in Chile next January on board the United States Coastguard ice-breaker, Polar Sea.

The Endurance was trapped and crushed by the ice a short distance from the coast in an expedition to cross the Antarctic on foot. The trapped vessel drifted for hundreds of miles before sinking in the Weddell Sea, leaving the survivors cut off from the rest of the world for eighteen months. In an incredible feat of survival, rescue and leadership, Shackleton salvaged the three lifeboats and embarked on an eighteen-month ordeal involving an 800-mile crossing of the stormiest seas in the world, a trek across South Georgia's unmapped mountains, and repeated attempts, in four different ships, to rescue alive all 28 men on the expedition.

Ice-breakers, satellites, sonar and mini-Subs deploy from Chile

Using equipment of a kind Shackleton never dreamed of in his era of husky dogs, sledges and reindeer-hide sleeping bags, Dr Ballard will deploy sonar, satellites, and two remote-controlled mini-submarines, called Argus and Little Hercules, to try to detect and photograph the wreck, 9,000 feet (2,770 metres) below the surface topped by twenty feet (six metres) of pack ice. He will concentrate on the search area in the Antarctic summer in the few days in February when NASA satellites have indicated in three of the past four years that it is least likely to be ice-bound.

Despite the difficulties and the inhospitable environment, Dr Ballard is confident he can find the wreck. He has already narrowed down the likely position to within a few square miles (kilometres). "It is going to be difficult", he says. "The Antarctic is not a forgiving place". Just in case his vessel is trapped as Shackleton's was, her sister, Polar Star, will be standing by.

He believes the wreck of the Endurance will be well-preserved. While Shackleton and his men salvaged what they could as the vessel went down, she still contained unique relics and many photographic slides of one of the most famous expeditions of Antarctica's heroic age.

Dr Ballard, a former United States Navy Commander, has an outstanding record as a veteran of 100 deep-sea