NASA's DART mission is on track to launch in June 2021 and collide with an asteroid called Didymos in 2022.
Humans are preparing to punch the solar system — but in self-defense, not anger.
It's all part of a NASA mission in development called the Double Asteroid Redirection Test, or DART. Unlike most spacecraft the agency has launched to date, DART isn't about gathering scientific data and learning more about how the universe works. Instead, it's NASA's first planetary-defense mission.