A New Threat

On September 3, 1949, a U.S. Air Force WB-29 aircraft from the 375th Weather Reconnaissance Squadron landed at Eielson Air Force Base, Alaska, with filter paper samples collected east of the Soviet Union's Kamchatka Peninsula. Tests on the samples showed anomalously high levels of airborne radioactive debris—high enough to be explained only by an atomic explosion.

Joe-1 atomic testSoviet Union's "Joe-1" atomic test. Photograph courtesy of the Federation of American Scientists.

Intelligence sources in the United States reported that scientists in the Soviet Union were pushing hard to develop a nuclear capability, but it appeared that they were having trouble. The consensus was that the Soviets were still about three years away from completing a working atomic bomb. Nevertheless, the United States began routine monitoring to detect atomic explosions in the Soviet Union.

The radioactive filter paper samples were flown to a lab in Berkeley, California, and the test results were reported to the Air Force. Independent tests were conducted by the Los Alamos Scientific Laboratory, by the British Atomic Energy Authority on airborne samples collected north of Scotland, and by the Naval Research Laboratory on rainwater collected in Kodiak, Alaska, and in Washington, D.C. Each of the tests confirmed high levels of radioactivity.

On September 19, Vannevar Bush, then president of the Carnegie Institution, convened a special panel in Washington, D.C. This panel formally concluded that the USSR had exploded its first atomic bomb, code-named Joe-1, on August 29, 1949.

Soviet bomberSoviet Tupolev 16 "Badger" bomber.

The announcement by President Harry Truman on September 23, 1949, of an atomic explosion by the Soviet Union shocked the nation. Even worse news came out a short time later. Not only did the Soviet Union have the bomb, it had also developed long-range aircraft able to reach the United States via an Arctic route. The United States had no defense against nuclear attack. The Ground Control of Intercept (GCI) radar network developed during World War II had been designed to defend against an attack with conventional weapons, and it had only a limited ability to detect incoming hostile aircraft. A wave of Soviet bombers carrying nuclear weapons would almost certainly succeed in evading detection by these radars.

Map of Soviet bombing routesSoviet bombing routes (click on image for a larger view).

A sense of fear and helplessness began to pervade the United States. Civil defense groups built air-raid shelters, and parents trained their children for the possibility of a nuclear war. Today, these perceptions and actions might seem unrealistic and excessive, but in 1949 these fears were very real.

The United States had grown accustomed to having a monopoly on nuclear weapons. Americans had felt invulnerable, and efforts to maintain military installations had been reduced to minimal levels. The Soviet Union's atomic bomb ended this period of complacency, and the USSR became the Red Menace. Stories about Joseph Stalin's purges and labor camps, though incomplete, further enhanced the feeling of dread. That Stalin might use nuclear weapons seemed entirely plausible.

These perceptions compelled the Department of Defense (DoD) to reevaluate the nation's defenses against nuclear attack. As a part of the process, the DoD assigned the U.S. Air Force the task of improving the nation's air defense system. The Air Force, in turn, asked the Massachusetts Institute of Technology for assistance—and this led to the formation of MIT Lincoln Laboratory.


Adapted from E.C. Freeman, ed., Technology in the National Interest, Lexington, Mass.: MIT Lincoln Laboratory, 1995.

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