An asteroid NASA’s Lucy spacecraft flew by, Donaldjohanson, reveals a violent past and evidence of ancient liquid water, providing a prehistoric window into the building blocks of our early solar system.
Lucy encountered Donaldjohanson, a primitive fragment from a massive collision 155 million years ago. This flyby provides crucial data on the building blocks that once assembled planets like Earth in our early system.
Scientists detected iron-bearing phyllosilicates on the surface, indicating the presence of ancient liquid water. This mineral evidence suggests the object formed in the outer solar system before migrating into the inner main belt.
Discovering more about an asteroid NASA’s Lucy spacecraft flew by
An asteroid NASA’s Lucy spacecraft flew by, Donaldjohanson, is a bi-lobed fragment formed from a catastrophic collision 155 million years ago. This body contains iron-bearing phyllosilicates, proving that liquid water once altered its primitive chemical structure.
Researchers confirmed the asteroid belongs to the Erigone family, identifying it as a fossilized link to planetary assembly. The encounter occurred in April 2025 during Lucy’s long-duration trek toward Jupiter’s Trojan swarms.
Observations utilizing the L’LORRI instrument provided high-resolution imagery and false-color maps of surface slopes. These visuals highlight the specific bi-lobed geometry and primitive composition of this inner main belt object.
The bi-lobed structure of DJ

Donaldjohanson features two distinct lobes joined by a smooth neck, a shape common among diverse solar system bodies like comets and near-Earth asteroids. This geometry often results from low-velocity collisions where fragments are eventually bound by mutual gravity. Reconstructing these contact binaries helps researchers understand the violent impact history defining the early asteroid belt.
Ancient origins and water signatures
The detection of phyllosilicates suggests that water-ice was likely present on the parent body before the collision. This implies the object formed in the outer asteroid belt or beyond before migrating inward.
| Property | Data Point |
| Parent Body Age | 155 million years |
| Family Name | Erigone family |
| Key Mineral | Iron-bearing phyllosilicates |
| Flyby Date | April 20, 2025 |
Scientific importance and theories
Studying an asteroid NASA’s Lucy spacecraft flew by supports theories regarding planetary migration and the delivery of organics to early Earth. If primitive bodies relocated to the inner belt, they might have ferried life’s essential building blocks toward our planet during a period of massive solar system shuffling.
Connecting DJ to Jupiter Trojans

Research suggests an asteroid NASA’s Lucy spacecraft flew by shares chemical similarities with Eurybates, a specific Trojan asteroid target. Both objects potentially originated in the cold outer solar system, providing a unique bridge for comparing diverse populations within the current main asteroid belt.
Planetary migration and the fossil record
An asteroid NASA’s Lucy spacecraft flew by offers a window into the past through its primitive chemical makeup.
- Jupiter and Saturn migrations herded minor bodies into the asteroid belt.
- Primitive asteroids act as fossilized remnants of planetary building blocks.
- Aqueous alteration in Donaldjohanson likely terminated early due to radioactive decay.
- The Erigone family formed from a single 50-mile-wide parent body.
Implications and what comes next
NASA’s Lucy mission continues toward the L3 and L4 Lagrange points to encounter Eurybates in 2027. Comparing an asteroid NASA’s Lucy spacecraft flew by with Trojan targets will reveal how organic materials were distributed during ancient planetary migrations.
Future data will clarify if these inner-belt primitive bodies are the primary source of Earth’s water. This research remains foundational for mapping the evolutionary chain that led to the formation of the inner solar system.
Conclusion
Analyzing the primitive nature of an asteroid NASA’s Lucy spacecraft flew by provides foundational knowledge of our cosmic history. These fossilized remnants tell the story of Earth’s assembly and chemical origins. Explore more on our YouTube channel—join NSN Today.



























