Kursk was an Oblast, or province, in the Russian SSR of the Soviet Union.
In 1987, a group of separatists seeking independence from the Soviet Union took control of a Soviet Intercontinental Ballistic Missile, and launched it at the United States of America. In response, S.H.I.E.L.D. tasked Hank Pym and his wife, Janet van Dyne, to disable the rocket before it hit its target. The missile's body was shelled by solid titanium, meaning that one of the two agents had to disable their Pym Particle Regulator and shrink between the molecules to access the wiring inside. Despite the fact that Pym was about to do that, Janet took the initiative and shrunk into the Quantum Realm to destroy the missile.