NASA scientists continue to analyze data collected during Lucy’s encounter with the main belt asteroid Donaldjohanson. They have recently published new images of a celestial body that looks somewhat like a chicken leg or a dumbbell.
Lucy’s encounter with the asteroid took place on April 20, 2025. It was not the main objective of the mission — the primary task of the spacecraft is to study Jupiter’s Trojan asteroids. However, NASA scientists decided to seize the opportunity and fly by the passing object. In this way, they achieved two objectives simultaneously: they investigated a previously unknown celestial body and conducted a dress rehearsal before the start of the main part of the scientific program, testing Lucy’s instruments.
Lucy’s images show that Donaldjohanson is larger than previously thought: it is 8 km long and 3.5 km wide at its widest point. The asteroid rotates very slowly, completing one rotation in just 251 hours. In addition, assumptions that Donaldjohanson has a strongly elongated shape have been confirmed; the photos show that it resembles a dumbbell or a chicken leg.
The mission team recently released a new image taken by the spacecraft from a distance of 1,700 km just a few minutes before it reached its closest approach. To date, this is the most detailed image on which the asteroid can be seen in its entirety. The smallest visible details are about 40 km in size. Since the Sun was almost behind Lucy at the time of the image taking, this significantly reduced the contrast of the topographic details in the image.
NASA also published a stereo pair: the last complete image of Donaldjohanson (right) and a slightly cropped image taken 72 seconds later (left).
Lucy is now moving away from the Sun at a speed of over 50,000 km/h, heading toward its main target. According to mission specialists, the successful dress rehearsal provides confidence that both the spacecraft and the team are well prepared for the upcoming encounters with Jupiter’s Trojan asteroids.
According to NASA
