One of the most feared weapons of the Second World War was named by its own crews after a lovesick girl in a pop song. This episode explores the Soviet BM-13 Katyusha, from the letter K stamped on launchers at the Comintern factory that linked it to Matvey Blanter's hit, to the German nickname Stalin's Organ inspired by its rail silhouette and shrieking launch. We trace the engineering path from Nikolai Tikhomirov's 1928 solid-propellant experiments and Georgy Langemak's RS-82 and RS-132 aircraft rockets to the failed sideways-mounted truck prototypes and V. N. Galkovsky's fix of aligning the rails along the chassis.

Traditional artillery officers were skeptical of a weapon that took roughly 50 minutes to load and fired everything in seven to ten seconds, so only 40 launchers existed when Germany invaded in June 1941. Captain Ivan Flyorov's ...