Deep Sea Drilling Project, U.S. program designed to investigate the evolution of ocean basins by core drilling of ocean sediments and underlying oceanic crust. Funded by the National Science Foundation, the project was directed by the Joint Oceanographic Institution for Deep Earth Sampling (JOIDES), a consortium of leading U.S. oceanographic institutions. Begun in 1964, a test drilling program was completed successfully in 1965; by 1968, the Glomar Challenger, displacing 10,500 tons and capable of drilling 2,500 ft (760 m) of sediment in 20,000 ft (6,100 m) of water, was leased to JOIDES. The scientific operations carried out on board consisted of continuous seismic and magnetic surveys while underway, in-hole measurements, and laboratory analysis of the cores recovered. The project verified that the present ocean basins are relatively young and confirmed aspects of seafloor spreading and plate tectonics. It also discovered thick bedded salt layers from cores taken out of the Mediterranean Sea, indicating that the sea completely dried up between 5 and 12 million years ago; that Antarctica has been covered with ice for the last 20 million years; and that the northern polar ice cap was much more extensive 5 million years ago. The Deep Sea Drilling Project drilled about 600 holes into the ocean floors over the world, about one hole per 308,880 square mi (800,000 square km). The Ocean Drilling Program (ODP), begun in 1983 and supported by a U.S.-led consortium that included 25 nations, was the successor of the Deep Sea Drilling Project. The program employed the drillship JOIDES Resolution and was managed by Joint Oceanographic Institutions (JOI). On more than 110 cruises, it drilled in poorly sampled areas, including continental margins and ocean trenches. In addition, the ODP contributed to other programs, such as drilling holes in which to lower seismic instruments necessary for a global seismic network project. A total of 1,797 holes were drilled at 669 sites. The Integrated Ocean Drilling Program (IODP), which began in 2003, succeeded the ODP. The U.S. National Science Foundation and Japan's Ministry of Education, Culture, Sports, Science and Technology are the lead agencies. Other participating international organizations are the European Consortium for Ocean Research Drilling, China's Ministry of Science and Technology, the Interim Asian Consortium, the Australian-New Zealand IODP Consortium (ANZIC), and India's Ministry of Earth Science. The program's major research vessels are the drillship Chikyu, which is operated by Japan's Center for Deep Earth Exploration, and the JOIDES Resolution, which is managed by the U.S. Implementing Organization. The Chikyu has an improved drilling system that allows it to drill more deeply than previous drillships. The IODP will examine the biosphere under the ocean floor, seek information on climatic change recorded in seafloor cores, and investigate mass and energy transfers between the crust and mantle.