NASA’s DART spacecraft successfully slammed into a distant asteroid at hypersonic speed on Monday in the world’s first test of a planetary defense system, designed to prevent a potential doomsday meteorite collision with Earth. From a report: Humanity’s first attempt to alter the motion of an asteroid or any celestial body played out in a NASA webcast from the mission operations center outside Washington, D.C., 10 months after DART was launched. The livestream showed images taken by DART’s camera as the cube-shaped “impactor” vehicle, no bigger than a vending machine with two rectangular solar arrays, streaked into the asteroid Dimorphos, about the size of a football stadium, at 7:14 p.m. EDT (2314 GMT) some 6.8 million miles (11 million km) from Earth. The $330 million mission, some seven years in development, was devised to determine if a spacecraft is capable of changing the trajectory of an asteroid through sheer kinetic force, nudging it off course just enough to keep Earth out of harm’s way. Whether the experiment succeeded beyond accomplishing its intended impact will not be known until further ground-based telescope observations of the asteroid next month. But NASA officials hailed the immediate outcome of Monday’s test, saying the spacecraft achieved its purpose.