The W78 is an American thermonuclear warhead with an estimated yield of 335–350 kilotonnes of TNT (1,400–1,460 TJ), deployed on the LGM-30G Minuteman III intercontinental ballistic missile (ICBM) and housed in the Mark 12A reentry vehicle. Minuteman III initially carried the older W62 warhead with a yield of 170 kilotonnes of TNT (710 TJ), but starting in December 1979 and ending in February 1982, some W62 were replaced with the W78. It is publicly estimated that 1083 warheads were manufactured.[1]