NASA Lucy Dates Asteroid Donaldjohanson at 155 Million Years Ahead of 2027 Trojan Flyby
Updated
Updated · Scientific American · Jun 18
NASA Lucy Dates Asteroid Donaldjohanson at 155 Million Years Ahead of 2027 Trojan Flyby
3 articles · Updated · Scientific American · Jun 18
Summary
A Science study from NASA’s Lucy team says asteroid Donaldjohanson is about 155 million years old, based on crater counts from the spacecraft’s 2025 flyby.
Lucy’s measurements also found the peanut-shaped asteroid matches the carbon-rich Erigone family and contains water-altered minerals from a larger parent body shattered in an ancient collision.
Images suggest sunlight-driven spin changes helped create its slow tumble and narrow neck, while missing small craters there point to landslides and possibly an impact about 40 million years ago.
The results give Lucy a relatively young asteroid “anchor point” for testing how space rocks evolve before the mission reaches its first Trojan target, Eurybates, on Aug. 12, 2027.
How might Lucy's upcoming encounter with Trojan asteroids challenge our current understanding of solar system formation?
If Donaldjohanson’s youth and dynamic history are typical, how might this reshape theories about asteroid evolution across the solar system?
What secrets about water in the early solar system might be hidden in Donaldjohanson’s minerals, and could similar clues await at the Trojans?
Lucy's Dress Rehearsal: Scientific Breakthroughs from the Donaldjohanson Flyby and Implications for Trojan Exploration
Overview
NASA's Lucy mission, launched to explore the Jupiter Trojan asteroids, reached a major milestone with its successful flyby of the main-belt asteroid Donaldjohanson in April 2025. This event acted as a crucial dress rehearsal, allowing the team to test Lucy's instruments and operational procedures while collecting valuable scientific data. The images and measurements from Donaldjohanson helped the team refine their techniques and confirmed the spacecraft's readiness. These experiences and insights are essential as Lucy prepares for its main mission, where studying the unique Trojan asteroids is expected to challenge and expand our understanding of how the solar system formed.