NASA has shared the first closeup images of the Donaldjohanson asteroid, captured by its Lucy spacecraft on a recent flyby around 139 million miles (223 million km) from Earth.
Our #LucyMission took a look at asteroid Donaldjohanson, its second asteroid encounter on its journey to Jupiter’s Trojan asteroids. The first images reveal a unique fragment of an asteroid that formed about 150 million years ago! Find out more: https://t.co/Bgg5CkQfYd pic.twitter.com/lgZRG8Qngh
— NASA (@NASA) April 21, 2025
Prior to Lucy’s flyby, Donaldjohanson had only been observed from Earth, with no previous spacecraft having visited it at close range. Lucy’s encounter provides the first detailed, high-resolution views of the asteroid — believed to have formed some 150 million years old — revealing its shape, geology, and other characteristics for the first time.
Lucy’s images were collected as the spacecraft flew around 600 miles (960 km) from Donaldjohanson on April 20.
“Asteroid Donaldjohanson has strikingly complicated geology,” Hal Levison, principal investigator for Lucy, said in a release. “As we study the complex structures in detail, they will reveal important information about the building blocks and collisional processes that formed the planets in our solar system.”
The team studying the close-up images have been surprised by the odd shape of the narrow neck connecting the two lobes, which NASA said “look like two nested ice cream cones.”
Initial analysis of the imagery suggests that the Donaldjohanson asteroid is about 5 miles (8 km) long and 2 miles (3.5 km) wide at the widest point — larger than originally estimated.
NASA said it will take a few more days to downlink the rest of of the encounter data from the spacecraft, at which point it will be able to make a better judgment regarding the asteroid’s overall shape. Data collected by Lucy’s other scientific instruments — the L’Ralph color imager and infrared spectrometer and the L’TES thermal infrared spectrometer — will be retrieved and analyzed over the next few weeks.
Lucy also made a close flyby of the Dinkinesh asteroid in 2023, but neither that one nor Donaldjohanson is the primary target of the Lucy mission. They were simply flybys as the spacecraft heads to the Jupiter Trojan asteroid Eurybates, which it’s set to reach in August 2027.
“These early images of Donaldjohanson are again showing the tremendous capabilities of the Lucy spacecraft as an engine of discovery,” said Tom Statler, program scientist for the Lucy mission. “The potential to really open a new window into the history of our solar system when Lucy gets to the Trojan asteroids is immense.”
And in case you’ve been wondering, the asteroid Donaldjohanson is named after American paleoanthropologist Donald Johanson, who discovered the “Lucy” fossil skeleton in in Ethiopia in 1974 in what’s regarded as a key find in the study of human evolution. The naming of the asteroid honors Johanson’s significant contribution to science, and also creates a symbolic link with NASA’s Lucy spacecraft, which is itself named after the famous fossil.
