Operation Buffalo was followed by Operation Antler in 1957, which tested new, light-weight nuclear weapons. Three tests were conducted in this series: Tadje (, Biak and Taranak . The first two were conducted from towers, while the last was suspended from balloons. Tadje used cobalt pellets as a tracer for determining yield, resulting in rumours that Britain was developing a cobalt bomb. Between 1956 and 1963, the Maralinga site was also used for minor trials, tests of nuclear weapons components not involving nuclear explosions. Kittens were trials of neutron initiators; Rats and Tims measured how the fissile core of a nuclear weapon was compressed by the high explosive shock wave; and Vixens investigated the effects of fire or non-nuclear explosions on atomic weapons. Ultimately, the minor trials generated more contamination than the major tests.