Flyby of Asteroid Donaldjohanson by NASA’s Lucy Spacecraft

On April 20, 2025, NASA’s Lucy spacecraft marked a pivotal milestone in its mission with a close flyby of asteroid Donaldjohanson, offering scientists a unique opportunity to study remnants from the early solar system.

A Mysterious Object in the Main Asteroid Belt

Asteroid Donaldjohanson, located in the main asteroid belt between Mars and Jupiter, exhibits an elongated, irregular shape reminiscent of a lumpy bowling pin. Initial measurements estimate the asteroid to be approximately 8 kilometers in length and 3.5 kilometers in width—larger than previously anticipated. Imagery captured during the flyby reveals a contact binary structure: two lobes joined by a narrower neck. This morphology suggests a complex formation history, likely the result of a significant impact event around 150 million years ago.

A Successful Technical Maneuver

The spacecraft executed the flyby at a distance of approximately 960 kilometers. Utilizing its high-resolution L’LORRI imager, Lucy obtained detailed visual data of the asteroid’s surface. This maneuver served as a full-scale rehearsal for upcoming encounters with Jupiter Trojan asteroids scheduled between 2027 and 2033.

The asteroid Donaldjohanson as seen by the Lucy Long-Range Reconnaissance Imager (L’LORRI) on NASA’s Lucy spacecraft during its flyby. This timelapse shows images captured approximately every 2 seconds beginning at 1:50 p.m. EDT (17:50 UTC), April 20, 2025. The asteroid rotates very slowly; its apparent rotation here is due to the spacecraft’s motion as it flies by Donaldjohanson at a distance of 1,000 to 660 miles (1,600 to 1,100 km). The spacecraft’s closest approach distance was 600 miles (960 km), but the images shown were taken approximately 40 seconds beforehand, the nearest ones at a distance of 660 miles (1100 km). Credit: NASA/Goddard/SwRI/Johns Hopkins APL

Promising Scientific Data

Data collected during the flyby is currently being transmitted back to Earth. Scientists aim to analyze the asteroid’s surface composition, density, and geological evolution. These observations are expected to deepen our understanding of bodies formed during the early stages of the solar system.

A Symbolic Naming

The asteroid is named after American paleoanthropologist Donald Johanson, best known for co-discovering the australopithecine fossil Lucy in Ethiopia in 1974. Both the spacecraft and asteroid names celebrate the sciences of origins—human and planetary alike.

This encounter represents Lucy’s second asteroid flyby, following its approach to Dinkinesh in 2023. It is a critical step in preparation for the mission’s primary objective: the exploration of the Trojan asteroids. These objects may hold key insights into the formation of the giant planets. Lucy is scheduled to continue its journey through 2033, seeking to unveil the formative history of our solar system.

Source

Find the article published by NASA on 04/21/2025 here

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