NASA’s Lucy Probe Encounters Tumbling Asteroid Donaldjohanson, Detects Signs of Ancient Water

• June 19, 2026

NASA’s Lucy mission, en route to study Jupiter’s Trojan asteroids, recently completed a significant milestone by flying past the asteroid Donaldjohanson. This tumbling celestial body provided the spacecraft with an opportunity to perform detailed scientific observations early in its journey.

Before reaching its primary targets among the Trojan asteroid population, Lucy visited two other asteroids: Dinkinesh and Donaldjohanson. The probe’s flyby of these smaller bodies served as a crucial test of its scientific instruments and navigational capabilities.

Insights from the Donaldjohanson Encounter

The detailed data collected during the encounter with Donaldjohanson revealed compelling signs that the asteroid bears traces of ancient water. This discovery adds a valuable piece to understanding the history and composition of small bodies within our solar system.

Donaldjohanson’s irregular, tumbling motion presented a unique challenge for the mission team but also allowed for comprehensive surface analysis under different lighting and viewing angles. The results enrich the knowledge of how water and other volatile materials may have been distributed across asteroids that co-orbit with Jupiter.

As NASA continues the Lucy mission, these early observations set a strong foundation for the study of the larger Trojan asteroids, which hold key clues about the formation and evolution of the solar system. The presence of water-related compounds on Donaldjohanson also raises new questions about the processes shaping these distant, primitive objects.

While pricing and further mission details have not been disclosed, the successes of Lucy’s preliminary encounters demonstrate the technical proficiency of the spacecraft and promise significant scientific returns in the years ahead.

NASA’s Lucy spacecraft flew past the tumbling asteroid Donaldjohanson, uncovering evidence of ancient water on its surface.