NASA has launched a spacecraft on a mission to smash into an asteroid and test whether it would be possible to knock a speeding space rock off course if one were to threaten Earth.
The SpaceX Falcon 9 spacecraft is called DART, for Double Asteroid Redirection Test. It lifted off from California's Vandenberg Space Force Base.
If all goes well, in September 2022 it will slam head-on into Dimorphos, an asteroid 525 feet (160 meters) across, at 15,000 mph (24,139 kph).
The asteroid is no danger to Earth, just a good target for testing out the potentially planet-saving technology.
