Ground-Based Midcourse Defense

Ground-Based Midcourse Defense (GMD), previously National Missile Defense (NMD), is an anti-ballistic missile system implemented by the United States of America for defense against ballistic missiles, during the midcourse phase of ballistic trajectory flight. It is a major component of the American missile defense strategy to counter ballistic missiles, including intercontinental ballistic missiles (ICBMs) carrying nuclear, chemical, biological or conventional warheads.

Source: Wikipedia — Ground-Based Midcourse Defense (CC BY-SA 4.0)