ACR AG | 5 April 1984 Fact daa Defense Nuclear Agency S h eet Public Affairs Office 4. Washington, D.C. 20305 Operation CROSSROADS Operation CROSSROADS was an atmospheric nuclear weapon test series conducted in summer of 1946. The series consisted of two detonations, each with a yield of 23 KT: o ABLE -- detonated at an altitude of 520 feet (158 meters) on 1 July o BAKER -- detonated 90 feet (27 meters) underwater on 25 July. the It was the first nuclear test held in the Marshal Islands. The material. series was to stuay the effects of nuclear weapons on ships, equipment, and A fleet of more than SO vessels was assembled in Bikini Lagoon as a target. This target fleet consisted of older U.S. capital ships, three captured German and Japanese ships, surplus U.S. cruisers, destroyers and submarines, and a large number of auxiliary and amphibious vessels. Military equipment was arrayea on some of the ships as well as amphibious craft that were beached on Bikini Island. ducted to study nuclear weapon explosion phenomena. live animals. Technical experiments were also conSome experiments included the use of The support fleet of more than 150 ships provided quarters, experimental stations, and workshops for most of the 42,000 men (more than 37,000 of whom were Navy personnel) of Joint Task Force 1 (JTF 1), the organization that conducted the tests. Additional personnel were located on nearby atolls such as Enewetak and Kwajalein. The islands of the Bikini Atoll were used primarily as recreation and instrumentation sites. Before the first test, all Atoll. These men were personnel were evacuated from the target fleet and Bikini placed on units of the support fleet, which sortied Lagoon and took safe positions at least 10 nmi (18.5 km) east of the atoll. from Bikini In the ABLE test, the weapon was dropped from a B-29 and burst over the target fleet. In BAKER, the weapon was suspended beneath an auxiliary craft anchored in the midst of the target fleet. ABLE operations went smoothly except that the test weapon was dropped between 1,500 and 2,000 feet (457 and 610 meters) off target. only a transient effect, The radioactivity created by the burst had and within a day nearly all the surviving target ships had been safely reboarded. The ship inspections, instrument recoveries, and remooring necessary for the BAKER test proceeded on schedule. Five ships were sunk as a result of the test. The crews of the target ships that had been remanned following ABLE were evacuated prior to BAKER to the support fleet east of the atoll. BAKER sank eight ships and damaged more ships than ABLE. The detonation caused most of the target fleet to be bathed in radioactive water spray and radioactive debris from the lagcon bottom. With the exception of 12 target vessels anchored in the array and the landing craft beached on Bikini Island, the target fleet remained too on-board activities. radiclogically contaminated for several weeks for more than brief The inability to complete inspections on much of the target fleet threatened the success of the operation after BAKER. A program of target vessel decontamination was begun in earnest about 1 August. This involved washing the ships’ exteriors using work crews drawn