Nuclear weapons tests in Australia known at the time as Christmas Island (not to be confused with Christmas Island in the Indian Ocean) between 1957 and 1958. These were airbursts mostly occurring over water or suspended a few hundred metres above the ground by balloon. In Australia there were three sites. Testing was carried out between 1952 and 1957 and was mostly done at the surface. A few hundred smaller scale tests were conducted at both Emu Field and Maralinga between 1953 and 1963. Two separate atomic test projects occurred at the islands, the first being Operation Hurricane and the second being Operation Mosaic The
Operation Sandstone at Los Alamos on July 9 to make arrangements for the tests. They readily agreed that they would be scientific in nature, with Los Alamos supplying the technical direction and the armed forces providing supplies and logistical support. The cost of the tests, around $20 million, was divided between the Department of Defense and the Atomic Energy Commission. Lieutenant General John E. Hull was designated as test commander. Rear Admiral William S. Parsons and Major General William E. Kepner reprised their Operation Crossroads roles as deputy commanders. Joint Task Force 7 was formally activated on October 18, 1947. As its