November 1, 1952 The first thermonuclear device, code named "Mike," detonated by the Commission at Enewetak, during Operation Ivy. The device exploded with a yield at 10.4 megatons, March-June 1953 The Commission conducted Operation Upshot-Knothole at the Nevada Test Site, detonating eleven explosions including shots "Simon" and "Harry." July 2, 1953 Lewis L. Strauss became new chairman of August 20, 1953 The Soviet Union detonated a large fission weapon which burned same the Atomic Energy Commission. thermonuclear fuel. The United States called the shot Joe 4. November 28, 1953 U.N. Disarmament Commission created subcommittee of Five; members were United States, Soviet Union, Canaca, France, and Great Britain. December 8, 1953 President Eisenhower delivered "Atoms for Peace" speech before the United Nations. January 21, 1954 U.S.S. Nautilus, the first nuclear powered submarine, launched by the Navy. February 1954 In a Memorandum of Understanding signed by the Commission, the Public Health Service accepted responsibility for monitoring off-site radiation. March-May 1954 The Cammission conducted Operation Castle at the Marshall Islands, which consisted of six tests. March 1, 1954 "Bravo," the first shot of Castle, exploded with a force of fifteen megatons, the largest announced U. S. nuclear test. June 29, 1954 The Cammission announced that it denied Dr. J. Robert Oppenheimer access to restricted data.