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
Built-in self-test a periodic test will assure that the device has not become unsafe since the power-on self test. Safety-critical devices normally define a "safety interval", a period of time too short for injury to occur. The self test of the most critical functions normally is completed at least once per safety interval. The periodic test is normally a subset of the power-on self test. One of the first computer-controlled BIST systems was in the U.S.'s Minuteman Missile. Using an internal computer to control the testing reduced the weight of cables and connectors for testing. The Minuteman was one of the first