In an unprecedented, save-the-world experiment, NASA is about to slam a spacecraft into a small, harmless asteroid millions of miles away.

It’s part of a test mission to determine if we can deflect dangerous incoming killer asteroids heading towards Earth and defend the planet from a potential future disaster. NASA hopes the impact will be enough to nudge the asteroid into a slightly tighter orbit around its companion space rock.

Cameras and telescopes will watch the crash, but it may take days or even weeks to find out if it actually changed the orbit, according to the Associated Press. The spacecraft that will soon turn to rubble is known as the Double Asteroid Redirection Test or DART. It is already on course traveling at about 14,000 miles an hour and is expected to make impact at 7:14 p.m. ET on Monday.

NASA Television will broadcast coverage of the end of this mission beginning at 6 p.m.

The target asteroid named Dimorphos is about 7 million miles (9.6 million kilometers) from Earth, according to the AP. It’s roughly 525 feet across and orbits its parent body at a distance of less than a mile. NASA insists there’s a zero chance either asteroid will threaten Earth — now or in the future, which is why they picked the pair.

The test is a $325 million effort that began in November 2021 and will be humanity’s first ever planetary defense test. Telescopes on all seven continents will view the collision and its aftermath for weeks, making observations that will let astronomers precisely measure how the asteroid’s path got altered, if at all, NPR reported. Although the intended nudge should change the moonlet’s position only slightly, NASA believes this will add up to a major shift over time.

In 2024, a European spacecraft named Hera will retrace Dart’s journey to measure the impact results.