Manhattan Project

Also found in: Dictionary, Thesaurus, Acronyms, Wikipedia.

Manhattan Project,

the wartime effort to design and build the first nuclear weapons (atomic bombsatomic bomb
or A-bomb,
weapon deriving its explosive force from the release of nuclear energy through the fission (splitting) of heavy atomic nuclei. The first atomic bomb was produced at the Los Alamos, N.Mex., laboratory and successfully tested on July 16, 1945.
..... Click the link for more information.
). With the discovery of fission in 1939, it became clear to scientists that certain radioactive materials could be used to make a bomb of unprecented power. U.S. President Franklin Delano Roosevelt responded by creating the Uranium Committee to investigate this possibility. Progress was slow until Aug., 1942, when the project was placed under U.S. Army control and reorganized. The Manhattan Engineer District (MED) was the official name of the project. The MED's commanding officer, Gen. Leslie R. GrovesGroves, Leslie Richard,
1896–1970, American army officer and engineer who headed the program that developed America's atomic bomb, b. Albany, N.Y., grad. West Point (1918).
..... Click the link for more information.
, was given almost unlimited powers to call upon the military, industrial, and scientific resources of the nation.

A $2-billion effort was required to obtain sufficient amounts of the two necessary isotopes, uranium-235 and plutonium-239. At Oak Ridge, Tenn., the desired uranium-235 was separated from the much more abundant uranium-238 by a laborious process called gaseous diffusion. At the Hanford installation (Wash.), huge nuclear reactors were built to transmute nonfissionable uranium-238 into plutonium-239. This method was based on the principle of the self-sustaining nuclear reaction (nuclear pile) that had first been achieved under the leadership of Enrico FermiFermi, Enrico
, 1901–54, American physicist, b. Italy. He studied at Pisa, Göttingen, and Leiden, and taught physics at the universities of Florence and Rome. He contributed to the early theory of beta decay and the neutrino and to quantum statistics.
..... Click the link for more information.
 at the metallurgical laboratory of the Univ. of Chicago. At the radiation laboratory of the Univ. of California at Berkeley costly efforts were made to separate the two uranium isotopes using cyclotrons, but only about a gram of pure uranium-235 was obtained. The actual design and building of the plutonium and uranium bombs took place at Los Alamos, N.Mex., under the leadership of J. Robert OppenheimerOppenheimer, J. Robert
, 1904–67, American physicist, b. New York City, grad. Harvard (B.A., 1925), Ph.D. Univ. of Göttingen, 1927. He taught at the Univ. of California and the California Institute of Technology from 1929 (as professor from 1936) until his appointment
..... Click the link for more information.
. Gathered at this desert laboratory was an extraordinary group of American and European-refugee scientists.

The only nuclear test explosion, code-named Trinity, was of a plutonium device; it took place on July 16, 1945, near Alamogordo, N.Mex. The first uranium bomb ("Little Boy") was delivered untested to the army and was dropped on Hiroshima on Aug. 6, 1945, killing at least 70,000 inhabitants. On Aug. 9, 1945, a plutonium bomb virtually identical to the Trinity device was dropped on Nagasaki, killing at least 35,000 inhabitants.


See L. R. Groves, Now It Can Be Told (1962); L. Lamont, Day of Trinity (1965); H. Feis, The Atomic Bomb and the End of World War II (rev. ed. 1966); R. Rhodes, The Making of the Atomic Bomb (1987); R. S. Norris, Racing for the Bomb (2002).

Manhattan Project

[man′hat·ən ‚prä‚jekt]
A United States project lasting from August 1942 to August 1946, which developed the atomic energy program, with special reference to the atomic bomb.
References in periodicals archive ?
Cindy Kelly, the foundation's president, believes the Manhattan Project park could interest American youth in science and engineering by celebrating the innovators who harnessed atomic energy for the first time.
Incredibly, Roosevelt had kept Truman in the dark about the Manhattan Project during his brief time as FDR's vice president.
One reason that the British were willing to merge their own nuclear weapons work into that of the Manhattan Project was that the sheer burden of continuing the conventional war against Hitler, amid the risks of German bomber and missile attacks, made it unlikely that Britain could produce atomic bombs before World War II had ended.
Department of Energy that could lead to the establishment of a Manhattan Project National Historical Park.
Politicians, scientists, economists and even regular citizens have rallied behind the notion that the nation needs a Manhattan Project to achieve "energy independence," "clean energy," "freedom from foreign oil," "relief at the pump"--whatever the slogan of the day might be.
Speaking at Oak Ridge National Laboratory, Alexander, chairman of the Senate Republican Conference, said he chose the lab for his announcement because "this was one of three secret cities that were the principal sites for the original Manhattan project that split the atom to build the bomb that won World War II.
The purpose of the Manhattan Project was to find a way to split the atom and build a bomb before Germany could.
Making the plutonium bomb-building process especially difficult is the problem that Rhodes cites as the most difficult task in the Manhattan Project from the scientists' perspective: taking a hollow sphere of plutonium, crushing its 30 pounds into a softball sized compacted sphere, and releasing a stream of neutrons within it on a timetable of a few microseconds.
Scientists during the Manhattan Project achieved this by adding a small amount of gallium.
Some historians believe that the Manhattan Project during World War II was without precedent.
A president might establish a vison or a goal, as in the Manhattan Project.
His Manhattan Project would change the world and challenge his own ethics.

Full browser ?