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- 52246 Donaldjohanson on Wikipedia
52246 Donaldjohanson
Details
52246 Donaldjohanson is a carbonaceous main-belt asteroid that NASA’s Lucy spacecraft flew past in 2025. The encounter revealed an elongated contact binary with two lobes joined by a narrow neck.
52246 Donaldjohanson became a known world rather than a distant point of light when NASA’s Lucy spacecraft swept past it in April 2025. The encounter was Lucy’s second asteroid flyby and a rehearsal for the mission’s later visits to Jupiter’s Trojan asteroids, but Donaldjohanson proved scientifically striking in its own right.
Lucy revealed a deeply elongated contact binary: two distinct lobes joined by a narrow neck. The full views show how strongly the asteroid departs from a simple rounded body, while craters and boulders across the surface turn its unusual outline into a geologically detailed landscape.
The names connect the encounter to a much older story. The asteroid honors paleoanthropologist Donald Johanson, co-discoverer of the Lucy fossil, while the spacecraft takes its name from the same famous hominin. Donaldjohanson therefore links an asteroid flyby to the history of studying human origins without losing its own identity as a newly resolved small world.
3.85km
Key facts
- Category
- Asteroids
- Object class
- C-type main-belt asteroid
- Composition
- Carbonaceous rock
- Scale fact
- 8.8 kmmaximum extent
- Estimated age
- ~150 million years
Scale context
Where 52246 Donaldjohanson sits on the full axis
By size on the journey, 52246 Donaldjohanson sits between 19P/Borrelly and Halley's Comet. The band below compares 52246 Donaldjohanson with nearby C-type main-belt asteroid objects so the size jump stays easy to read.
Shared physical scale
50.5km
Together, these objects make the size change around 52246 Donaldjohanson easy to compare at a glance.
Sources
References for 52246 Donaldjohanson
Measurements and descriptive context are compiled by the Scale of Space team from the references below. If you find an error, please let us know.
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Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.
Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.