In the 1970s, the situation that had prevailed for several decades, during which only the members of the United Nations (UN) Security Council – Britain, China, France, the United States, and the USSR – had nuclear weapons was beginning to erode. India tested a device in 1974; a number of other countries, including Israel, South Africa, and Taiwan, were suspected of having active programs; and even more countries were interested in eventually having this ultimate power to destroy or deter. A world in which many countries had nuclear weapons would be a markedly more dangerous one. As a result, there was intense interest at the senior levels of the American government in monitoring nuclear weapons programs so that, if a country showed signs of making serious progress toward having nuclear weapons, efforts could be made to stop it.

At 3:00 a.m., Washington time, on September 22, 1979, a U.S. satellite detected an intense double flash of light in the southern hemisphere. Such a double flash was characteristic of a nuclear explosion, so there were immediately questions to intelligence analysts about whether there had been a nuclear explosion and, if so, who had been responsible. The satellite, however, had been launched more than a decade before, and its capabilities had deteriorated. Not enough data were generated by the satellite to confirm that the flash actually had been a nuclear explosion.