NASA will smash its DART spacecraft into an asteroid on Monday. Here's how to watch.

NASA's Double Asteroid Redirection Test (DART) spacecraft is set to slam into an asteroid on Monday (Sept. 26), in the first ever test of humanity's ability to deflect life-threatening space rocks before they collide with Earth.

The 1,210-pound (550 kilograms) DART craft, a squat cube-shaped probe consisting of sensors, an antenna, an ion thruster and two 28-foot-long (8.5 meters) solar arrays, will smash into the asteroid Dimorphos while traveling at roughly 13,420 mph (21,160 km/h).