(52246) Donaldjohanson
This main belt asteroid serves as a full dress-rehersal for Lucy's future Trojan asteroid encounters. While it was selected as an enginnering target, it is also an interesting object itself as it has been identified as a fragment of a massive collision that occurred around 150 million years ago that produced the Erigone family of asteroids. This makes it an extremely young, at least compared to most other objects in the Solar System and will be interesting to compare to other main belt asteroids, including Dinkinesh .
Donaldjohanson is named after the paleoanthropologist who discovered the Lucy fossil. Like Johanson, the Lucy mission strives to connect past to present, with asteroids as “fossils” of the Solar System.
This graphic displays asteroid Donaldjohanson (boxed in white) moving amongst background stars as seen by Lucy from 45 million miles away (70 million km). These alternating images, taken on Feb 20 and Feb 22, were released on February 25th, 2025, just 53 days before encounter! To the bottom right, you can see a different asteroid passing through the field of view!
Credit: NASA/Goddard/SwRI/Johns Hopkins APL/NOIR
A top-down, Solar System view showing Lucy's trajectory during the Donaldjohanson encounter on April 20, 2025. White: asteroids that Lucy will fly by. Grey: select other Trojan asteroids. Blue: Earth. Red: Lucy spacecraft. Orange: Jupiter.
Credit: NASA/Goddard/SwRI/ASU
Banner Image: The Donaldjohanson encounter insignia, interlaced silhouettes of Donald Johanson and the Lucy fossil. Credit: Goddard/SwRI