NASA’s Lucy Reveals Wobbling, Peanut-Shaped Asteroid

Even small asteroids lead complex lives. During its flyby of the asteroid Donaldjohanson last year, NASA’s Lucy spacecraft revealed the asteroid to be a wobbly, peanut-shaped body that has undergone a lot of activity in its relatively short history. Formed as fragments coalesced after a violent collision 155 million years ago, the asteroid was transformed by the small but inexorable force of the Sun’s radiation, all while retaining signs of the brief presence of liquid water in its distant past. Zooming through the main asteroid belt toward one of the Jupiter Trojan asteroid groups, the Lucy spacecraft collected the first close-up images and other data at Donaldjohanson on April 20, 2025, as it passed 650 miles away from the asteroid. The data revealed that, instead of spinning simply around one axis like most other asteroids and planets, Donaldjohanson has a more complicated two-axis rotation. Scientists also saw Donaldjohanson’s peanut shape and the craters and ridges on its surface. Lucy’s encounter with the asteroid was planned as a dress rehearsal for the spacecraft and mission team before its primary asteroid encounters, which begin with Lucy’s flyby of the Trojan asteroid Eurybates on Aug. 12, 2027. …