NASA’s Lucy mission has set its sights on 1 asteroid. It has been found 2.

Wednesday NASA Lucy spacecraft zoomed in on its first asteroid target – and scientists on the mission were shocked to discover that the rock was given its name Dinkinesh, were actually two rocks. The binary star consists of a larger, primary asteroid and a smaller ‘moon’ orbiting it, as seen in images captured by Lucy of the pair.

“We knew this would be the smallest main belt asteroid ever seen up close,” Keith Noll, astronomer and Lucy project scientist at NASA Goddard Space Flight Center, said in a statement. press release. “The fact that there are two makes it even more exciting.”

Lucy’s flight was a pit stop for more ambitious targets: two groups of asteroids called the Trojan Swarms. The Trojans, leftover pieces from the formation of the outer planets, are locked into stable orbits of the Sun along the same path as the planet Jupiter. Lucy will visit nine additional space rocks through 2033, part of NASA’s broader orbit attempt to gain knowledge of our heavenly neighborhood.

“The Trojans are the last large population of objects that we have not yet seen up close,” said Thomas Statler, a NASA planetary scientist who took part in the mission. “And Lucy is going to do that for the first time.”

NASA has given the mission a name after a skeleton discovered in 1974 in Ethiopia that revolutionized scientists’ understanding of human evolution. Likewise, “we hope that looking at these fossils of planetary origin will give us insight into the origins of our solar system,” said Dr. Statler.

Lucy’s meeting with Dinkinesh was coincidental. When the mission launched in 2021, the previously unnamed asteroid was not part of Lucy’s space journey. But the mission team discovered that with a small adjustment to Lucy’s course in Maythe spacecraft was able to pass within a radius of 420 kilometers of the space rock, which was given the Amharic name for the Lucy skeleton, Dinkinesh.

The focus of this meeting was not on scientific discoveries, said Hal Levison, a planetary scientist at the Southwest Research Institute and principal investigator of the Lucy mission. Instead, he said, it was an in-flight test of Lucy’s asteroid tracking system. Minutes before the closest approach, which occurred around 12:55 a.m. Eastern on Wednesday, Lucy “connected” with Dinkinesh and automatically adjusted to keep the rock in his line of sight.

Lucy sped past Dinkinesh at 10,000 miles per hour as the scientific instruments captured images of the asteroid’s surface and measured the composition and structure of the rock. When she finished, Lucy’s antenna swiveled back to the eagerly waiting science team on Earth.

Preliminary studies of Lucy’s first images of the pair of asteroids indicate that the larger rock is about 800 meters wide, while the satellite is about 0.25 kilometers wide.

Amy Mainzer, an astronomer at the University of Arizona who is not involved with the Lucy mission, said studying Dinkinesh could help explain how similarly sized asteroids migrated close to Earth, some close enough to potentially pose a threat for our planet.

But Lucy’s scientific goals lie far beyond Earth’s environment. After orbiting the sun and encountering another main belt asteroid – this one named after Donald Johansonone of the paleontologists who discovered the Lucy skeleton – the spacecraft will reach the Trojans before Jupiter in 2027. Another solar loop will take it to the swarm of asteroids tracking Jupiter in 2033.

The Trojans are “actually very different from each other,” said Dr. Levison. “And we didn’t expect that when we started studying them.” Data that reveals more information about the conditions under which they formed may provide clues that support the theory that the outer planets first appeared much closer to the sun and eventually spread further away in more stable orbits.

But whatever secrets the Trojans hold, the mission team expects them to contribute to the knowledge that space rocks reveal about our cosmic beginnings. “There is no such thing as just an asteroid,” said Dr. Statler. “Everyone carries with them a memory of a different part of our solar system’s history.”

Putting this story together, he added, “gives us insight into where we come from at the molecular level, and how we are connected to our solar system and to our universe.”