How to watch as NASA sends a spacecraft to deliberately crash into a 525-foot-wide asteroid at 15,000 mph

NASA scientists are gearing up for the world's first mission testing planetary defense — and they want you to watch.

The space agency's Double Asteroid Redirection Test (DART) will test technology to defend Earth against future asteroids and comets by deliberately crashing into an asteroid — which poses no threat to Earth — at some 15,000 mph. The target, a larger asteroid's moonlet named Dimorphos, measures about 525 feet wide. 

The goal of the test is to prove that a spacecraft can autonomously navigate to a specific asteroid and purposely crash into it, disintegrating on impact and changing the object's speed and path. Scientists aim to measure that change using telescopes on Earth.