Get ready for a stellar road trip! On April 20, 2025, NASA’s Lucy spacecraft will zoom past asteroid 52246 Donaldjohanson, marking the second stop on its ambitious 12-year journey through the solar system. Launched in October 2021, Lucy is on a mission to explore the Trojan asteroids—mysterious space rocks that share Jupiter’s orbit around the Sun. But before it gets there, it’s making a quick detour through the main asteroid belt, and Donaldjohanson is next on the itinerary.
Why Donaldjohanson?
This isn’t just any asteroid. Named after the paleontologist Donald Johanson, who discovered the famous “Lucy” Australopithecus fossil in 1974, 52246 Donaldjohanson is a small but intriguing target. Estimated to be about 4 kilometers (2.5 miles) wide, it’s a C-type asteroid—rich in carbon and possibly holding clues to the solar system’s early days. For scientists, this flyby is like opening a time capsule from 4.5 billion years ago, offering a glimpse into the building blocks that formed planets like Earth.
Lucy’s visit to Donaldjohanson isn’t just a warm-up for its Trojan adventures—it’s a chance to test the spacecraft’s instruments and gather data on a different kind of asteroid. Unlike the Trojans, which are locked in Jupiter’s gravitational dance, Donaldjohanson hangs out in the main asteroid belt between Mars and Jupiter. Comparing these cosmic neighbors could unlock secrets about how our solar system evolved.
What to Expect
On April 20, Lucy will swoop within a few hundred kilometers of Donaldjohanson at a blistering speed of about 7.4 kilometers per second (16,500 miles per hour). During this brief encounter, its high-tech cameras and spectrometers will snap photos and analyze the asteroid’s surface composition, shape, and size. While the spacecraft won’t slow down or land—this is a flyby, not a pit stop—the data it collects will be beamed back to Earth over the following days and weeks.
For space fans, this event won’t be visible from your backyard (sorry, no asteroid-spotting with binoculars this time). But NASA will share updates, images, and findings as they roll in, so keep an eye on their official website or social media channels for the latest cosmic postcards.
Why It Matters
Lucy’s mission is all about piecing together the solar system’s family tree, and Donaldjohanson is a key chapter. By studying this asteroid, scientists hope to learn more about the materials that swirled around the young Sun billions of years ago. It’s a bit like archaeology in space—except instead of digging through dirt, we’re flying through the void to uncover our origins.
Plus, this flyby is a milestone for Lucy. After buzzing Earth in 2022 for a gravity assist, this is its second asteroid encounter (the first was Dinkinesh in 2023). Each stop fine-tunes the spacecraft for its main event: reaching the Trojans by 2027. Think of Donaldjohanson as a practice run for the big show.
How to Join the Fun
While you can’t watch the flyby live, you can still get in on the action. Follow NASA’s Lucy mission updates online, or dive into the science with resources from The Planetary Society. Want to impress your friends? Tell them Lucy’s journey spans over 6 billion kilometers (4 billion miles) and that it’s powered by solar panels stretching 7 meters (23 feet) across—pretty cool for a spacecraft exploring the dark reaches of space!
Mark your calendar for April 20, 2025, and stay tuned for what Lucy reveals about Donaldjohanson. It’s a small step for a spacecraft, but a giant leap for our understanding of the cosmos. Who knows? The next big discovery might just be a flyby away.
Cosmic Watchers 
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