Meaning of "Katyusha/KATUSA"

Ka-Chyu-Sya/Ka-Tu-Sa/KATUSA

Katyusha/KATUSA카츄샤/카투사/KATUSA#사회/이슈

South Korean Army personnel assigned to the U.S. Eighth Army to support U.S. forces and carry out joint missions

"While serving in the Katyusha, he participated in various joint exercises with U.S. forces."