A human ancestor who lived so long ago stimulated a mission to understand the solar system
Before dawn on a Saturday in October 2021, an Atlas V rocket rose from Cape Canaveral carrying Lucy — a spacecraft named for a 3.2 million-year-old human ancestor — on a twelve-year, four-billion-mile journey to study Jupiter's Trojan asteroids, the solar system's oldest unexamined remnants. NASA's $981 million mission asks a question as old as curiosity itself: what were the conditions that made worlds, and by extension, made us? In reaching backward toward the solar system's origins, humanity is, in a sense, reaching toward its own.
- A spacecraft carrying lab-grown diamonds, Beatles lyrics, and the weight of human origins lifted off at dawn — a mission unlike any attempted before it.
- Eight asteroids across two Trojan swarms, a record for a single mission, demand a trajectory so complex NASA's own science chief once doubted it was possible.
- Three gravity assists from Earth across eight years will slingshot Lucy through the outer solar system, threading a needle between the late 2020s and 2033.
- Scientists describe the launch with the language of birth and wonder, bracing for surprises from rocks that may have remained untouched since the solar system's first moments.
- Lucy is now en route to pass within 600 miles of each target — close enough to reveal mountains, valleys, and answers to questions about planetary formation that no instrument has yet been able to ask.
On a Saturday morning in October, an Atlas V rocket lifted off from Cape Canaveral carrying NASA's Lucy spacecraft on a twelve-year journey spanning nearly four billion miles. The $981 million mission is aimed at something never before attempted: a close study of Jupiter's Trojan asteroids — ancient rocks sharing the gas giant's orbit, thought to be pristine remnants of the solar system's formation.
The spacecraft's name carries its own history. Lucy is named after a 3.2 million-year-old human ancestor fossil discovered in Ethiopia, itself nicknamed after the Beatles song "Lucy in the Sky with Diamonds." NASA honored the connection by etching band members' words onto a plaque aboard the craft and including lab-grown diamonds in one of its scientific instruments. Ringo Starr recorded a video tribute for the launch. Donald Johanson, the paleoanthropologist who discovered the original fossil, watched the rocket rise from Cape Canaveral in person. "I will never look at Jupiter the same," he said afterward.
Lucy's path is intricate: gravity assists from Earth in 2022 and 2024 will build enough speed to reach Jupiter's orbit, with a warm-up flyby of asteroid Donaldjohanson in 2025. By the late 2020s, Lucy will encounter five asteroids in the Trojans' leading cluster, then swing back past Earth in 2030 before chasing two more in the trailing cluster in 2033 — eight asteroids total, a record for any single mission. Each pass will bring the spacecraft within 600 miles of its target.
What those ancient rocks will reveal remains unknown. Scientists expect mountains, valleys, and details never before seen — and they expect to be surprised. For the mission's lead scientist, watching the launch felt like witnessing a birth. For the rest of us, it marks the beginning of humanity's first systematic look at the fossils of our solar system's earliest chapter.
On a Saturday morning in October, before the sun had fully cleared the horizon, an Atlas V rocket lifted off from Cape Canaveral carrying a spacecraft named Lucy on a journey that would take nearly twelve years and span almost four billion miles. The mission had cost NASA $981 million, and it was aimed at something that had never been attempted before: a close study of Jupiter's Trojan asteroids, those thousands—possibly millions—of ancient rocks that share the gas giant's orbit around the sun.
The spacecraft's name carried weight beyond the mission itself. Lucy was named after a 3.2 million-year-old skeleton of a human ancestor discovered in Ethiopia decades earlier. That fossil had been nicknamed after a Beatles song from 1967, "Lucy in the Sky with Diamonds," a connection NASA honored by sending the spacecraft aloft with the band members' words etched onto a plaque. The spacecraft also carried a disc made of lab-grown diamonds as part of one of its scientific instruments. Ringo Starr, the Beatles' drummer, recorded a video message for the launch, paying tribute to John Lennon and the song that had inspired it all. "I'm so excited—Lucy is going back in the sky with diamonds," Starr said. "Johnny will love that."
Donald Johanson, the paleoanthropologist who had discovered the original Lucy fossil, traveled to Cape Canaveral to witness the launch himself. Watching the rocket rise, he felt the weight of the moment—a human ancestor who had lived millions of years ago had, in a roundabout way, inspired a mission to unlock secrets of the solar system's formation. "I will never look at Jupiter the same," he said afterward. "That a human ancestor who lived so long ago stimulated a mission which promises to add valuable information about the formation of our solar system is incredibly exciting."
For the scientists involved, the emotional stakes were high. Hal Levison, the mission's lead scientist at Southwest Research Institute, described the launch as witnessing the birth of a child. The path Lucy would take was intricate and unconventional—so much so that Thomas Zurbuchen, NASA's science mission chief, had initially questioned whether it was even possible. The spacecraft would swing past Earth in October 2022 and again in 2024, using the planet's gravity to gain enough speed to reach Jupiter's distant orbit. Along the way, it would make a warm-up pass by an asteroid named Donaldjohanson in 2025, positioned between Mars and Jupiter.
Once Lucy reached the Trojan swarms in the late 2020s, it would encounter five asteroids in the leading cluster. Then came another gravity assist from Earth in 2030, which would send the spacecraft back outward to chase two more asteroids in the trailing Trojan cluster in 2033. Eight asteroids in total—a record for a single mission. The largest of these targets measured roughly seventy miles across. Lucy would pass within six hundred miles of each one, close enough for its instruments to capture unprecedented detail.
The Trojans themselves remained largely mysterious. These asteroids were thought to be pristine remnants from the solar system's formation, untouched by the collisions and transformations that had shaped the inner planets. They orbited far from Jupiter and scattered far from each other, which meant Lucy faced essentially no risk of collision as it moved among them. But what those ancient rocks would reveal—whether they held mountains, valleys, pits, or mesas—remained unknown. Hal Weaver, who oversaw Lucy's black-and-white camera at Johns Hopkins University, spoke to the anticipation: "Who knows? I'm sure we're going to be surprised. But we can hardly wait to see what images will reveal about these fossils from the formation of the solar system."
The launch marked the beginning of humanity's first systematic exploration of Jupiter's Trojan population, a mission that would fundamentally reshape understanding of how planets form and how the solar system came to be. For twelve years, Lucy would travel through space, carrying with it the name of an ancestor and the dreams of scientists who believed these ancient asteroids held answers to some of humanity's oldest questions about its place in the cosmos.
Notable Quotes
I will never look at Jupiter the same. That a human ancestor who lived so long ago stimulated a mission which promises to add valuable information about the formation of our solar system is incredibly exciting.— Donald Johanson, paleoanthropologist who discovered the original Lucy fossil
Are there mountains? Valleys? Pits? Mesas? Who knows? I'm sure we're going to be surprised.— Hal Weaver, Johns Hopkins University, Lucy camera lead
The Hearth Conversation Another angle on the story
Why name a spacecraft after a fossil? It seems like an odd connection.
It's not random. The original Lucy—the skeleton—was named after a Beatles song. NASA took that thread and ran with it, making the connection explicit. The spacecraft carries the song's lyrics, lab-grown diamonds, even a message from Ringo Starr. It's a way of saying that understanding our past and understanding the solar system's past are linked.
But practically speaking, what makes these Trojan asteroids worth visiting?
They're thought to be pristine leftovers from when the solar system formed. They haven't been battered and reshaped like the inner planets. If you want to know what the raw materials of planetary formation looked like, the Trojans are your best archive.
Twelve years is a long time. Why so long?
The route is deliberately circuitous. Lucy has to swing past Earth twice to build up enough speed to reach Jupiter's orbit. Then it visits asteroids in two separate clusters, which requires another Earth gravity assist in between. It's complicated, but it's the only way to visit eight targets in a single mission.
What happens if something goes wrong out there?
The Trojans are scattered far apart, so collision risk is essentially zero. But twelve years in space is a long time for any machine. The real test is whether the instruments stay functional and whether the solar panels—two huge circular wings—keep drawing power.
What will scientists actually be looking for when Lucy gets there?
Details. Mountains, valleys, craters, composition, structure. These asteroids have never been studied up close. Lucy will pass within six hundred miles of each target, close enough to see things we've never seen before. That's where the real discovery happens.