Operation Deep Freeze (OpDFrz or ODF) is codename for a series of United States missions to Antarctica, beginning with "Operation Deep Freeze I" in 1955–56, followed by "Operation Deep Freeze II", "Operation Deep Freeze III", and so on. (There was an initial operation before Admiral Richard Byrd proposed 'Deep Freeze'). Given the continuing and constant US presence in Antarctica since that date, "Operation Deep Freeze" has come to be used as a general term for US operations in that continent, and in particular for the regular missions to resupply US Antarctic bases, coordinated by the United States military. Task Force 199 was involved. Prior to International Geophysical Year The U.S. Navy already had a record of earlier exploration in Antarctica. As early as 1839, Captain Charles Wilkes led the first U.S. Naval expedition into Antarctic waters. In 1929, Admiral Richard E. Byrd established a naval base at Little America I, led an expedition to explore further inland, and conducted the first flight over the South Pole. From 1934 to 1935, the second Byrd Expedition explored much further inland and also "wintered over". The third Byrd Expedition in 1940 charted the Ross Sea. Byrd was instrumental in the Navy's Operation Highjump after World War II from 1946 to 1947, which charted most of the Antarctic coastline. In 1948, Commander Finn Ronne led an expedition that photographed over 450,000 square miles (1.1 million km2) by air. Then in 1954–55, the icebreaker USS Atka made a scouting expedition for future landing sites and bays. Operation Deep Freeze I The impetus behind Operation Deep Freeze I was the International Geophysical Year 1957–58. IGY as it was known was a collaborative effort among forty nations to carry out earth science studies from the North Pole to the South Pole and at points in between. The United States along with New Zealand, the United Kingdom, France, Japan, Norway, Chile, Argentina, and the U.S.S.R. agreed to go to the South Pole, the least explored area on Earth. Their goal was to advance world knowledge of Antarctic hydrography and weather systems, glacial movements, and marine life. The U.S. Navy was charged with supporting the U.S. scientists for their portion of the IGY studies. Rear Admiral Richard E. Byrd, a veteran of four previous Antarctic Expeditions, was appointed as officer in charge of the expedition. In 1955, Task Force 43, commanded by Rear Admiral George J. Dufek, was formed