Heavy ICBM is a term that was created in the 1970s to describe a class of Soviet ICBMs (intercontinental ballistic missiles). They were characterized by a heavy throw-weight of 5 to 9 metric tons, several times that of an LGM-30 Minuteman, and a length of over 35 meters, and were thus capable of delivering a large number of warheads in a single MIRV missile.