The first hydrogen bomb test, code-named Ivy Mike, occurred in late 1952 as part of Operation Ivy; it vaporized the islet of Elugelab. This test included B-17 Flying Fortress drones to fly through the radioactive cloud to test onboard samples. B-17 mother ships controlled the drones while flying within visual distance of them. In all, 16 to 20 B-17s took part in this operation, of which half were controlling aircraft and half were drones. To examine the explosion clouds of the nuclear bombs in 1957/58, several rockets (mostly from rockoons) were launched. One USAF airman was lost at sea during the tests.