Lucy’s flyby observations showed that Dinkinesh is similar in shape to near-Earth asteroids Bennu and Ryugu, which are both known to be rubble pile asteroids (loose collections of rocks and dust held together by gravity, rather than solid objects), suggesting that it might have the same structure. This gives researchers an opportunity to study a similar kind of asteroid in a different part of the Solar System, and could also shed light on whether rubble pile asteroids change once they leave the main belt and enter near-Earth space.
The Dinkinesh system also has similarities to another near-Earth pair: asteroid Didymos and its moonlet Dimorphos, which were impacted by the DART spacecraft in 2022. Although the contact binary satellite is different from the lone Dimorphos, this still gives scientists the chance to compare the nature of binary asteroids in different environments.
Dinkinesh and its moonlets are the smallest main-belt asteroids ever visited by a spacecraft. Smaller asteroids have been explored by spacecraft, but only near-Earth ones.
What’s next for Lucy
Lucy is already zipping through space toward its next target, the main belt asteroid Donaldjohanson (named after the paleontologist who co-discovered the Lucy fossil), which it will reach in 2025. This flyby is intended to be another test of the Terminal Tracking System to prepare for encounters with the mission’s main targets, the Jupiter Trojan asteroids, starting in 2027. But as the Dinkinesh flyby has proved, even a technology test can yield exciting insights into the bodies of our Solar System.