B61 Thermonuclear Bomb. The B61 was designed as a tactical and strategic nuclear bomb that could be dropped by aircraft moving at a high rate of speed. Production of the bomb began in 1968 and it is expected to remain in service for the foreseeable future. The bomb can be carried and dropped by most American combat aircraft. The basic bomb weighs about 700 lbs. and is capable of producing a blast in the 0.3-340 kiloton range depending on the warhead used.