What could go wrong?

NASA Is Going to Knock an Asteroid Out of Orbit in First-Ever Planetary Defense Test

In what's being touted as the first-ever test of a true planetary defense system, NASA has teamed up with the European Space Agency (ESA) to try and knock an asteroid off course by slamming into it with a special probe traveling at roughly four miles per second. The Double Asteroid Redirect Test (DART) project involves targeting the asteroid known as Didymos and a much smaller rock that orbits it, deemed "Didymoon," and essentially punching the latter off its course. Neither of these monster space rocks poses a threat to Earth -- they'll both be seven million miles away from the planet at their closest point -- which is why they were chosen to serve as the test objects.

SUCE: https://www.thrillist.com/news/nation/nasa-attempt-to-knock-asteroid-out-of-orbit-2022