Blok 2BL
The Blok 2BL was a rocket stage, a member of Blok L family, used as an upper stage on some versions of the Molniya-M carrier rocket. It was used as a fourth stage to launch the Oko missile early warning defence spacecraft.
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Wikipedia
The Blok 2BL was a rocket stage, a member of Blok L family, used as an upper stage on some versions of the Molniya-M carrier rocket. It was used as a fourth stage to launch the Oko missile early warning defence spacecraft.