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Chronology of Development

One half century of nuclear weapons development, use and testing from the Manhattan Project (1942) through the testing moratorium (1992).

Events that took place at the Nevada Test Site (NTS) are in italics.

1942 Creation of Manhattan Project
1942 First nuclear chain reaction, University of Chicago
1943 Los Alamos Laboratory Established
1945 Trinity test, humankind's first nuclear explosion (21 kt)
1945 Atomic bombings of Hiroshima (15 kt) and Nagasaki (21 kt), Japan; WW II ends
1946 Operation Crossroads begins U.S. postwar atomic testing in Pacific
1947 Atomic Energy Commission Established
1949 First Soviet atomic test
1951 Operation Ranger, first tests at newly established Nevada Proving Grounds
1951 George, 1st U.S. thermonuclear test in Pacific (225 kt)
1952 Livermore Laboratory established
1953 1st Soviet thermonuclear test
1954 Bravo, highest yield U.S. atmospheric test in Pacific (15 mt)
1955 Groom Lake facility (Area 51) established northeast of Yucca Flat (NTS)
1955 Rover/Nuclear Rocket Development Station
1957 Hood, highest yield atmospheric test at NTS (74 kt)
1957 First anti-nuclear protest at the NTS
1957 Rainier, 1st contained underground test (1.7 kt)
1958 Testing moratorium (Eisenhower administration)
1961 Testing moratorium ends
1962 Sedan test, Plowshare crater
1963 Limited Test Ban Treaty bans atmospheric tests
1964 Experimental (EPA) farm established
1968 Boxcar, highest yield underground test (1.3 mt)
1970 Baneberry test venting
1970 Nuclear Nonproliferation Treaty
1973 Rover Program ends
1974 Threshold Test Ban Treaty signed
1976 Peaceful Nuclear Explosions treaty signed
1977 Department of Energy established
1978 MX Missile testing program begins
1979 Strategic Arms Limitation Treaty signed
1981 EPA Farm closed
1982 Lenten (later Nevada) Desert Experience vigils begin
1983 MX Missile program ends
1988 Largest anti-nuclear protest at NTS
1988 Intermediate-Range Nuclear Forces Treaty
1988 U.S./U.S.S.R. joint verification tests
1990 Threshold Test Ban and Peaceful Nuclear Explosions treaties ratified
1990 Radiation Exposure Compensation Act Passed
1991 Strategic Arms Reduction Treaty I signed
1992 Divider, last U.S. nuclear test (less than 20 kt)
1992 Testing moratorium (G.H.W. Bush administration)
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