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Cold War Films Yield New Effects-Data for U.S. Nuclear Weapons

The rush is on to save deteriorating atmospheric nuclear-testing films that give Department of Defense planners, emergency-preparedness officials, and weapons researchers irreplaceable hard data on the yield of nuclear weapons. Digitizing and reanalyzing these films is revealing surprises, causing weapons scientists and defense strategists to rethink what’s really in the nuclear stockpile.
July 1, 2015
Cold War Films Yield New Effects

The digitized image of the Badger test (top) of Operation Upshot-Knothole (1953), Nevada Test Site, has been enhanced (bottom) for a stronger contrast between the shock front (indicated by the arrow) and the sky behind it. Badger was originally estimated to yield 23-kilotons. With the shock wave now clearly visible, the yield can be estimated with far greater precision. (Photo: Open Source)


  • Managing Editor
  • Clay Dillingham
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The original analyses were prone to inaccuracies that make today’s weapon physicists scratch their heads.

Knowing the yield of a nuclear weapon design helps scientists and Department of Defense strategists predict its success in destroying its intended target. The trouble is, scientists can only determine yield indirectly—in particular, by taking measurements from films of each aboveground nuclear test. Scientists have been doing that since the dawn of the Nuclear Age. But since the United States abandoned atmospheric testing in 1963, researchers have been unable to gather much of the critical data needed to determine yield. The 50-plus-year-old test films are the only source of data, yet the old analytical methods produced significant inaccuracies.

To make up for that limited data, researchers are now scanning the aging, decomposing films and digitally enhancing the images. The results are enabling much more accurate yield estimates from the old films. The new data also help weapons planners to refine ongoing weapons designs and help emergency-response planners to evaluate threats from adversaries.