February 28, 1955
Report by the Measurement Lab of the USSR Academy of Science, 'On the Properties of the Atomic Bombs Detonated on the Marshal Islands in 1954'
Soviet scientific intelligence report on U.S. nuclear weapons testing on the Marshall Islands in 1954. This report concludes that the Ivy Mike and Castle nuclear detonations were thermonuclear based on gamma ray spectroscopy of fission fragments collected by Soviet aircraft over the USSR and PRC.
August 24, 1955
Report by N.M Emanuel, 'Regarding the Nature of the Fallout Path of the Hydrogen Bomb Detonated on 1 March 1954 at Bikini [Atoll]'
Report by N.M. Emanuel on the U.S. Castle Bravo test in the Marshall Islands. The report surmises from fallout data that the bomb used a fission-fusion-fission design, and that the bomb contained a larger than normal amount of fissile material which induced a thermonuclear reaction.