Soviet UFOlogy, some history and context

A few gems of real interest concerning the history of UFOlogy in the Soviet Union in the 70's and 80's, including a brief retelling of the famous case where a 900m-wide UFO prepared a Ukrainian Missle base for launch of its nuclear missles...

Good reading for context as concerning the various secret government UFO research efforts throughout the cold war (as far as we know), and for some eyebrow-raising stories of soviet fighter pilot encounters with mile-long 'black clouds' etc...