Aside from the B-29 bomber called Bockscar which dropped the atomic bomb on Nagasaki, another B-29 bomber also dropped three measuring instruments called "radiosonde" each with a parachute.
They were dropped to measure the atomic power and the explosion pressure. It is said that the US Army on Guam could confirm the explosion of the atomic bomb faster than anyone else by receiving the radio waves transmitted by these radiosondes.
Three radiosondes were blown away by the wind and found in the three villages of old Toishi-mura, old Tayui-mura, and old Enoura-mura, each about 12 kilometers east of the hypocenter.
