What NASA mission, launched in 2021, provided the first-ever close-up views of asteroid Donaldjohanson in April 2025?

The close-up views of asteroid Donaldjohanson in April 2025 were provided by NASA's Lucy mission, a spacecraft launched in October 2021. This encounter marked a significant milestone for the mission, serving as a crucial "dress rehearsal" for Lucy's primary objective: the exploration of the distant Trojan asteroids that share Jupiter's orbit. The flyby allowed mission scientists and engineers to test the spacecraft's instruments and navigation systems, ensuring they were ready for the more challenging encounters ahead.

Asteroid (52246) Donaldjohanson, located in the main asteroid belt between Mars and Jupiter, proved to be an intriguing target. Images returned by Lucy revealed it to be a contact binary, meaning it consists of two distinct lobes joined together, with a surprisingly complex geological structure. This C-type asteroid is approximately 8 kilometers (5 miles) long and 3.5 kilometers (2.2 miles) wide, and is believed to be a fragment from a massive collision that occurred about 150 million years ago, creating the Erigone family of asteroids. The asteroid was aptly named after paleoanthropologist Donald Johanson, who discovered the famous "Lucy" hominin fossil, a nod to the mission's goal of uncovering the solar system's ancient past.

The Lucy mission itself is a groundbreaking endeavor, designed to be the first space probe to explore the Jupiter Trojan asteroids. These ancient celestial bodies are considered "fossils of planet formation," holding clues to the origins and evolution of our solar system. Over its twelve-year journey, Lucy is set to visit a record-breaking number of asteroids, including another main-belt asteroid named Dinkinesh, before reaching its primary Trojan targets starting in 2027. Just as the Lucy fossil provided unprecedented insights into human evolution, the Lucy mission aims to revolutionize our understanding of planetary history.