In this photo released on Thursday Feb. 3, 2005 by the U.S. National Science Foundation, U.S. cargo ship American Tern arrives at McMurdo station, Antarctica, in Feb. 2005. Using a track smashed by icebreakers, U.S. cargo ships have sailed through Antarctic sea ice, nearly double its normal 77 kilometers (48 miles) width and between 1 1/2 and 3 meters (5-10 feet) thick, to offload supplies of food, fuel and equipment for science bases on the frozen continent. The American Tern offloaded sea containers of supplies for the bases, enough to support the science groups for the next 12 months. (AP Photo/U.S. National Science Foundation, HO)