In a thrilling leap for space exploration, NASA’s Lucy spacecraft successfully completed a close flyby of an asteroid named Donaldjohanson over the weekend of April 19–20, 2025. This maneuver marked the spacecraft’s second asteroid encounter and served as a crucial “dress rehearsal” before it reaches its first Trojan asteroid in 2027.
Launched in 2021, Lucy is the first mission designed to explore the Trojan asteroids — ancient remnants from the early days of the solar system that orbit the Sun alongside Jupiter. Following a successful asteroid flyby in 2023, this latest encounter helps fine-tune Lucy’s instruments and trajectory for its future rendezvous with the Trojans.
During the flyby, Lucy swooped within just 960 kilometers of Donaldjohanson, a 4-kilometer-long asteroid located in the main belt between Mars and Jupiter. Hurtling at a speed of over 48,000 kmph, Lucy deployed its three scientific instruments to capture detailed observations of the asteroid’s size, shape, and surface features. The data collected from the pass is expected to provide scientists with a sharper understanding of these ancient bodies — and will take about 12 minutes to travel back to NASA’s flight controllers in Colorado.
The asteroid is named after the famous fossil “Lucy,” the early human ancestor discovered in Ethiopia 50 years ago — a symbolic link between our search for terrestrial origins and our cosmic beginnings.
Dr. Hal Levison, principal investigator for the Lucy mission, remarked on the asteroid’s peculiar significance: “It’s not going to be a basic potato. We already know that,” he quipped, suggesting that Donaldjohanson’s shape and surface might reveal complex geological history. Some scientists speculate it could resemble Arrokoth, the distant Kuiper Belt object previously studied by NASA’s New Horizons mission in 2019.
Due to the high velocity of the approach, Lucy briefly turned its antenna away from Earth to aim its instruments precisely at the asteroid. Communication was minimal during the pass, but NASA scientists expect to receive a rich trove of data as the spacecraft reorients.
Looking ahead, Lucy’s grand tour of the solar system includes visits to eight Trojan asteroids between 2027 and 2033, including two pairs. Each encounter will provide valuable clues about the building blocks of planets and the chaotic, dynamic early history of our solar system.
This mission is far more than a cosmic sightseeing tour — it's a journey into the fossils of the universe itself. And with every flyby, Lucy peels back another layer of the mystery surrounding the origins of our solar system.