W70 was a two-stage, thermonuclear warhead that was developed for the MGM-52 Lance missile by the United States. Designed by Lawrence Livermore National Laboratory, the Mod 1 and Mod 2 version of the weapon entered service in 1973, while the enhanced radiation ("neutron bomb") Mod 3 weapon entered service in 1981.^[1] The last W70 warhead was dismantled in February 1996.^[2]

Design

The Mod 1 and Mod 2 versions of the weapon are estimated to have had a variable yield of 1 to 100 kilotonnes of TNT (4.2 to 418.4 TJ), while the Mod 3 enhanced radiation version was estimated to have a yield of 1 kilotonne of TNT (4.2 TJ)^[3] The Mod 1 reportedly had more yield options than the Mod 2 warheads. The Mod 3 was reportedly 40% fission and 60% fusion, with two yield options. The weapon weighed 270 lb (120 kg), and was 41 inches (100 cm) long and 18 in (46 cm) in diameter.^[4]

Mod 1 and 2 weapons were produced from June 1973 to July 1977, while Mod 3 weapons were produced from August 1983 to February 1984. 900 Mod 1 and 2 warheads and 380 Mod 3 warheads were manufactured. The last warheads were retired in September 1992.^[4]

The weapon was the successor to the previous proposed Lance warhead, the W63.^[4] The weapon used a category D Permissive Action Link and had command disable, but lacked insensitive high explosives and enhanced nuclear detonation safety.^[1]

The inventor of the neutron bomb, Samuel Cohen, has criticized the description of the W70 as a "neutron bomb":

the W-70 ... is not even remotely a "neutron bomb." Instead of being the type of weapon that, in the popular mind, "kills people and spares buildings" it is one that both kills and physically destroys on a massive scale. The W-70 is not a discriminate weapon, like the neutron bomb—which, incidentally, should be considered a weapon that "kills enemy personnel while sparing the physical fabric of the attacked populace, and even the populace too."^[5]