Ten months after launch, NASA's asteroid-deflecting DART spacecraft neared a planned impact with its target on Monday in a test of the world's first planetary defense system, designed to prevent a doomsday collision with Earth.
The cube-shaped "impactor" vehicle, roughly the size of a vending machine with two rectangular solar arrays, was on course to fly into the asteroid Dimorphos, about as large as a football stadium, and self-destruct around 7 p.m. EDT (2300 GMT) some 6.8 million miles (11 million km) from Earth.
The mission's finale will test the ability of a spacecraft to alter an asteroid's trajectory with sheer kinetic force, plowing into the object at high speed to nudge it astray just enough to keep our planet out of harm's way.
