Terminal guidance refers to the practice of steering a weapon in flight (cruise missile, guided gravity bomb, etc.) in the final moments before impact and/or detonation. Typically, it is used in the context of a particular weapon system to refer to the subsystem that performs this function. For example, the Tomahawk cruise missile uses DSMAC for terminal guidance. The Copperhead 155mm artillery shell uses a laser designation seeker for terminal guidance.