Which asteroid did NASA's DART spacecraft impact in 2022?

NASA’s DART spacecraft impacted Dimorphos in 2022. Dimorphos is the smaller member of the binary asteroid system Didymos, orbiting its larger companion rather than traveling alone around the Sun.

DART launched on November 24, 2021, and reached the Didymos system after a roughly 10-month journey. On September 26, 2022, the spacecraft deliberately struck Dimorphos at about 15,000 miles per hour. The mission tested the kinetic-impact method of planetary defense: nudging an asteroid’s orbit so it would miss Earth in a hypothetical future threat.

The collision shortened Dimorphos’s orbital period around Didymos by about 33 minutes, a much larger change than the spacecraft alone would have produced. Material blasted from the asteroid acted like recoil, adding momentum to the deflection. The impact also created a large dust plume and changed Dimorphos’s shape.

A common mix-up is naming Didymos as the target. Didymos is the larger primary body; Dimorphos is the asteroid moonlet that DART actually hit.