During 1964, Nikolai Kardashev proposed a threefold categorization of extraterrestrial cilivizations in terms of the power levels that could utilise in his article “Transmission of Information by Extraterrestrial Civilizations”.
The report entitled “Habitable Planets for Man” (dated March 1964) was written by Stephen Dole. It was sponsored by the US Air Force under Project RAND (Contract Number AF 49 (638) 700).
