Operation HIGHJUMP, officially titled The United States Navy Antarctic Developments Program, 1946–1947, (also called Task Force 68), was a United States Navy (USN) operation to establish the Antarctic research base Little America IV. The operation was organized by Rear Admiral Richard E. Byrd, Jr., USN (Ret), Officer in Charge, Task Force 68, and led by Rear Admiral Ethan Erik Larson, USN, Commanding Officer, Task Force 68. Operation HIGHJUMP commenced 26 August 1946 and ended in late February 1947. Task Force 68 included 4,700 men, 13 ships, and 33 aircraft. HIGHJUMP's objectives, according to the U.S. Navy report of the operation, were: Training personnel and testing equipment in frigid conditions; Consolidating and extending the United States' sovereignty over the largest practicable area of the Antarctic continent (publicly denied as a goal before the expedition ended); Determining the feasibility of establishing, maintaining, and utilizing bases in the Antarctic and investigating possible base sites; Developing techniques for establishing, maintaining, and utilizing air bases on ice, with particular attention to later applicability of such techniques to operations in interior Greenland, where conditions are comparable to those in the Antarctic; Amplifying existing stores of knowledge of electromagnetic, geological, geographic, hydrographic, and meteorological propagation conditions in the area; Supplementary objectives of the Nanook expedition (a smaller equivalent conducted off eastern Greenland). Timeline The Western Group of ships reached the Marquesas Islands on December 12, 1946, whereupon the USS Henderson and USS Cacapon set up weather monitoring stations. By December 24, the USS Currituck had begun launching aircraft on reconnaissance missions. The Eastern Group of ships reached Peter I Island in late December 1946. On December 30, 1946, the Martin PBM-5 George 1 crashed on Thurston Island killing Ensign Maxwell A. Lopez, ARM1 Wendell K. Henderson, and ARM1 Frederick W. Williams. The other 6 crew members were rescued 13 days later. These and Vance N. Woodall, who died on January 21, 1947, were the only fatalities during Operation HIGHJUMP. On January 1, 1947, Lieutenant Commander Thompson and Chief Petty Officer John Marion Dickison utilized "Jack Browne" masks and DESCO oxygen rebreathers to log the first dive by Americans under the Antarctic. Paul Siple was the senior U.S. War Department representative on the expedition. Siple was the same Eagle Scout who accompanied Byrd on the previous Byrd Antarctic expeditions. The Central Group of ships reached the Bay of Whales on January 15, 1947, where they began construction of