NASA’s Lucy spacecraft visited the asteroid 52246 Donaldjohanson on April 20, 2025, coming within 600 miles (920 kilometers) of the object located in the inner region of the asteroid belt between Mars and Jupiter.
The asteroid was named after the paleontologist Donald Johanson, who in 1974 co-discovered the first identified example of previously unknown type of hominid. They named the specimen “Lucy,” which is what the mission is named after. Like their namesakes, the mission and this asteroid could help us understand more about our origins.
The day after the encounter, NASA released images of Donaldjohanson taken by the Lucy LOng Range Reconnaissance Imager (L’LORRII), the craft’s high-resolution camera. They revealed that the asteroid is 5 miles (8 km) long — bigger than scientists expected — and 2 miles (3.5 km) at its widest point.
The images also revealed Donaldjohanson’s interesting peanut shape, with two lobes connected by a narrow neck. It appears to be an elongated contact binary, which occurs when an asteroid is formed by two objects coming together. But it could be more complicated than that, as scientists were surprised by the shape of the neck, which resembles two nested ice cream cones, according to a NASA news release. “Asteroid Donaldjohanson has strikingly complicated geology,” said Hal Levison, principal investigator for Lucy at Southwest Research Institute, in the release.
