NASA Was Caught Off Guard by What the Lucy Probe Just Detected

When NASA’s Lucy spacecraft was sent past a small asteroid named Dinkinesh in November 2023, the team treated it mostly as a dress rehearsal. The flyby was added late in the mission planning to test Lucy’s autonomous tracking system before it heads to its main targets, the Trojan asteroids near Jupiter. No one expected this tiny space rock to steal the show.

As the first images came down, the shock was immediate: Dinkinesh wasn’t alone. The pictures revealed that the asteroid actually had a companion, turning Lucy’s very first asteroid encounter into a two-for-one discovery. “Dinkinesh really did live up to its name; this is marvelous,” said Hal Levison, Lucy’s principal investigator at the Southwest Research Institute, noting that the Amharic name means “marvelous.”

Then things got even stranger. Follow-up images, captured minutes after closest approach, showed that the little moon itself was made of two objects gently touching each other, a configuration known as a contact binary. NASA later wrote that Lucy had observed “the first-ever contact binary orbiting another asteroid,” a configuration no one had anticipated from such a small, supposedly simple target.

What Lucy Actually Saw at Dinkinesh and Beyond

Detailed analysis of Lucy’s images revealed that Dinkinesh is more than just a rock with a weird moon. A later NASA article on the flyby showed a large trough slicing across the asteroid and a raised ridge nearby, evidence that a huge chunk—roughly a quarter of Dinkinesh—shifted in a single, dramatic event. “These features tell us that Dinkinesh has some strength,” Levison explained, adding that they let scientists “do a little historical reconstruction to see how this asteroid evolved.”

The tiny moon, now named Selam, turned out to be a contact binary: two lobes pressed together, orbiting the larger asteroid. Lucy deputy project scientist John Spencer said “we’ve never seen one orbiting another asteroid” and admitted the team “never suspected anything so bizarre.” Lucy program scientist Tom Statler at NASA Headquarters called it “truly marvelous when nature surprises us with a new puzzle,” saying good science pushes researchers to ask questions they never knew they needed to ask.

Lucy’s more recent flyby of another main-belt asteroid, Donaldjohanson, added to the sense of surprise. Speaking at the Southwest Research Institute, Levison described the object as looking “like two ice cream cones put together” and said the flyby revealed “head-scratching puzzlement” about how such shapes form. Statler told Space.com that “right now, we are in what has to be a Golden Age of asteroid exploration and understanding,” as dots of light turn into detailed new worlds.

Why These Odd Little Worlds Matter So Much

On the surface, Dinkinesh and Selam might look like curiosities—just another pair of oddly shaped rocks in the asteroid belt. But for planetary scientists, they’re a kind of fossil record. In a NASA article on the Dinkinesh images, Levison explained that “planets formed when zillions of smaller objects orbiting the Sun, like asteroids, ran into each other,” and that understanding whether those objects break apart or stick together “has a lot to do with their strength and internal structure.”

The new data suggest Dinkinesh is stronger than a loose pile of rubble. Researchers think that over millions of years, tiny forces from sunlight gradually spun the asteroid faster until part of it failed abruptly, more like an earthquake than a slow landslide, sending debris into orbit. Project scientist Keith Noll said the trough on Dinkinesh “suggests an abrupt failure… with a gradual buildup of stress and then a sudden release,” and some of that material likely re-settled as the ridge and the moon.

At Donaldjohanson, the story seems to be one of gentle collision. Lucy deputy principal investigator Simone Marchi said in a statement that the asteroid is “a fragment of a collision” where two objects “eventually came together in some way,” probably at a walking-pace impact speed so they could “gently collide and stick together.” These case studies help researchers test models of how small bodies merge, fracture, and evolve—crucial clues for understanding how Earth itself assembled from countless earlier building blocks.

What Lucy’s Surprise Discoveries Mean for the Mission’s Future

For the mission team, these unexpected findings are both a reward and a rehearsal. The Donaldjohanson encounter confirmed that Lucy’s instruments and flight operations can handle fast, close passes of oddly shaped targets; NASA’s mission update noted that the spacecraft “phoned home” in good health and is now steadily downlinking data for detailed study before it heads toward Jupiter’s Trojan swarms.

The Dinkinesh flyby, originally billed as an engineering test, has also turned into a scientific gold mine. Hal Levison joked to Space.com that with Dinkinesh, “we were wrong” about what to expect, but in a good way. Instead of a single, simple rock, Lucy has already visited a complex asteroid, discovered an extra moon, and found the first-ever contact binary orbiting another asteroid, all before reaching its main science targets.

And this is just the beginning. Over its 12-year journey, Lucy is slated to fly past 11 asteroids, including multiple Trojans that may preserve some of the most ancient material in the solar system. Statler put it this way in his conversation with Space.com: “We’re studying the leftover raw materials from the formation of the planets and trying to understand the history that made the Earth and our environment what it is.” With surprises already piling up, the mission’s biggest revelations may still be ahead.