Size of three spy satellites

As a comparison the illustration below shows the relative size difference between the three primary spy satellites that orbited the earth during the 1960’s, 1970’s and 1980’s. Even today the US intelligence agencies miss the global mapping capability that Hexagon provided. On the other hand some Hexagon imagery is still being used to determine the amount of global ice melting from those days compared to today and they have found that a huge amount of melting has occurred as a result of global climate change. See https://www.scientificamerican.com/article/cold-war-spy-satellites-reveal-substantial-himalayan-glacier-melt/