Ed Huntress wrote:


Kim Jong-Un doesn't need to buy old rockets from Ukraine. Rocket engine
schematic diagrams are readily available on the internet.

RS-25 schematic:
https://en.wikipedia.org/wiki/Space_Shuttle_main_engine#/media/File:Ssme_schematic_(updated).svg

This appears to be a Space Shuttle (STS) main engine, a VERY sophisticated
piece of turbomachinery. I seriously doubt the North Koreans could make one
of these work in less than a decade. It stretched the capabilites of the US
to make them work, and were a continuing source of problems throughout the
program.

Jon