NASA’s first planetary defense test mission began Tuesday with a launch out of Vandenberg Space Force Base along California’s Central Coast.

A SpaceX Falcon 9 rocket carrying the Double Asteroid Redirection Test — DART for short — blasted off at night, with the launch window opening around 10:20 p.m., according to a news release from the space base.

“Space Launch Delta 30 is excited to partner with NASA and SpaceX on the first planetary defense test mission,” Col. Rob Long, the launch decision authority, said in the release. “Everyone involved has been working tirelessly to ensure this launch is safe and successful. I’m proud of their efforts.”

A rendering of DART is seen in NASA's website.
A rendering of DART is seen in NASA’s website.

The purpose of DART is essentially to deliberately crash a spacecraft into an asteroid nearly head-on to change a near-Earth object‘s speed and trajectory, should one pose a threat to the planet in the future. That’s according to the Johns Hopkins University Applied Physics Laboratory, which helped develop the mission.

The current target — asteroid moonlet Dimorphos — poses no such threat to Earth, but will serve as the first official test of the planetary defense system, scientists say.

Dimorphos, which is approximately 160 meters in size, circles a larger asteroid named Didymos, and both in turn orbit the sun. With this mission, scientists will see if DART hitting the smaller object at a speed of approximately 15,000 mph will change its orbit within the binary asteroid system, according to the release.

The asteroid will be approximately 6.8 million miles from Earth when the collision takes place, something that isn’t anticipated until fall 2022.

“This asteroid system is a perfect testing ground to see if intentionally crashing a spacecraft into an asteroid is an effective way to change its course, should an Earth-threatening asteroid be discovered in the future,” the mission’s website states.

A ground-based telescope will be used to measure Dimorphos’ orbit before and after the collision to monitor for changes.

To date, no known asteroid larger than 140 meters poses a risk to Earth over the next century, although experts note that less than half of such asteroids have been discovered as of this past October, according to Johns Hopkins.

NASA defines a “potentially hazardous asteroid” as one that is at least 140 meters wide and has an orbit that will pass within 5 million miles of Earth.

One asteroid that received the classification, 2001 FO32, flew by Earth earlier this year, coming within 1.25 million miles of the planet on March 21.

Correction: A previous version of this story had the old name for the Vanderberg base. This post has been updated.