NASA finds crashing spacecraft into asteroids is a viable defence strategy

Plumes of dust and rocks kicked up from the surface of asteroid Dimorphos after NASA’s DART spacecraft smashed into it altered the space rock’s orbit more than the kinetic impact alone, according to research published on Wednesday.

Boffins successfully changed the position of an astronomical body in space for the first time in history during the Double Asteroid Redirection Test mission last October. A 610kg (1,345lb) spacecraft was directed to crash headfirst into an binary asteroid system to see whether it was possible to knock it off its original orbit.

DART was a huge success. The impact from the collision with Dimorphos shortened its orbit by 33 minutes – it now takes less than 11 and a half hours to circle around its parent asteroid, Didymos. The change is significantly greater than had been expected.

Researchers analyzing data from the experiment calculated that material ejected from Dimorphos’s surface during the collision changed its momentum by a greater amount than DART’s impact.