Can an asteroid on a collision course with our planet be deflected?
That's what NASA wants to find out.
On Thursday it introduced a spacecraft they plan to launch later this month, on a mission to crash into one.
They want to see if its impact will change the asteroid's course.
The Double Asteroid Redirection Test - or DART - is the space agency's first test mission of a planetary defense system.
They plan to target a double asteroid - Didymos and its moon Dimorphos.
Neither pose a threat to Earth, as NASA's planetary defense officer Lindley Johnson explained.
"This is a test. We don't want to be in a situation where an asteroid is headed toward Earth and then have to be testing this kind of capability. We want to know about both how the spacecraft works and what the reaction will be by the asteroid to the impact before we ever get in a situation like that."
The mission's success rests on the shape of the asteroid, which systems engineer Elena Adams says won't be known until the spacecraft gets there.
"Our impact angle on Dimorphos is really uncertain right now, and it's really going to depend on what Dimorphos actually looks like, and we're not going to find that out until the last, well, let's be honest, last 20 seconds when we are about to hit."
According to NASA's website, no known asteroid larger than 140 meters in size has a significant chance to hit Earth for the next hundred years.
But they also estimate that less than half of those asteroids are accounted for.
DART plans to launch the spacecraft on November 24 from California's Vandeberg Air Force base.
It is expected to reach the target asteroids by next fall.