NASA's Lucy spacecraft recently obtained its first clear images of the main belt asteroid 52246 Donaldjohanson, which is now within its line of sight. Lucy captured these images while it was 45 million miles (70 million kilometers) away from the asteroid. In the images taken by the spacecraft's Long Range Reconnaissance Imager (L'LORRI), the asteroid appears as a faint smudge of light against the backdrop of stars in the constellation Sextans.
The spacecraft is gearing up for a close flyby of Donaldjohanson on April 20, 2025. As reported by Gizmodo, Lucy will pass within 596 miles (960 kilometers) of the asteroid during this encounter. Over the next two months, Lucy will continue to image Donaldjohanson as part of its optical navigation program, adjusting its trajectory to ensure an accurate flyby on the scheduled date.
Donaldjohanson is a small main belt asteroid with a diameter of roughly 3 miles (4 kilometers) that orbits between Mars and Jupiter. Space.com notes that the asteroid is thought to be a piece of debris from a massive collision about 130 million years ago. Currently, Donaldjohanson is 70 million kilometers away from Earth and will remain a tiny point of light for weeks, not showing surface detail until the day of the encounter.
The asteroid holds special significance for the Lucy mission. It is named after anthropologist Donald Johanson, who discovered the fossilized skeleton called Lucy of a human ancestor in 1974. The mission itself is named after this fossil, reflecting its goal to uncover clues about our origins by studying asteroids, which are like fossils of planet formation.
Launched on October 16, 2021, Lucy is on its way to Jupiter's Trojan asteroids and has its next target in its sights: asteroid Donaldjohanson. As reported by Space.com, the spacecraft performed a gravity assist maneuver around Earth, increasing its speed with respect to the Sun by over 16,000 miles per hour (25,750 kilometers per hour). This maneuver helped Lucy gain speed toward the main asteroid belt while preparing for its rush toward Donaldjohanson.
In November 2023, Lucy observed the tiny main belt asteroid Dinkinesh and its contact-binary moon, Selam, during its flyby. Universe Today reports that the flyby of Dinkinesh was intended as a test for the spacecraft's braking system but also revealed that Dinkinesh has a small satellite, Selam, which is a contact binary composed of two connected bodies. Like Donaldjohanson, Dinkinesh and Selam are inhabitants of the asteroid belt between Mars and Jupiter.
The upcoming flyby of Donaldjohanson serves as a dress rehearsal for Lucy's future encounters with the Jupiter Trojans. The flyby will give Lucy mission personnel an opportunity to test and calibrate the spacecraft's navigation system and instruments. Lucy’s high-resolution camera, L'LORRI, spotted Donaldjohanson moving against a background of stars, using its apparent position to ensure an accurate flyby.
After the Donaldjohanson flyby, Lucy will continue its journey toward the Jupiter Trojans. The spacecraft's first encounter with a Trojan asteroid is scheduled for August 12, 2027, when it will meet the 620-mile-wide (1,000-kilometer-wide) 3548 Eurybates, as reported by Gizmodo. Lucy will perform flybys of a group of Trojan asteroids in the coming years, providing valuable insights into these clusters of rock and ice that never coalesced into planets when the Solar System formed.
Asteroids are considered leftovers from the dawn of the solar system and can tell us much about Earth's origin. The Jupiter Trojans are thought to provide the most well-preserved evidence from that era. By studying these asteroids in all their diversity, the Lucy mission will hopefully help scientists reconstruct their origins and how they were captured by Jupiter.
The Lucy mission is part of NASA's Discovery Program. The spacecraft was built by Lockheed Martin Space in Littleton, Colorado. NASA's Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and safety and mission assurance for the mission.
The article was written with the assistance of a news analysis system.