An SM-3 interceptor erupted into the night sky over Guam late on Tuesday, its engine briefly illuminating the northeast corner of the island as it accelerated toward its target: a ballistic missile. U.S. Missile Defense Agency and military personnel monitored the radars and telescopic cameras tracking both projectiles; this was not an attack, but a complex test.

Within minutes, the ballistic missile — air-launched from a U.S. Air Force C-17 — was pulverized by the kinetic energy of the SM-3.

The collision more than 600 kilometers up was a violent milestone in the United States' multibillion-dollar plan to turn its Western Pacific territory, closer to potential adversary China than any U.S. state, into one of the most heavily defended places on earth.