Visualizations by
Kel Elkins
Released on October 21, 2019
Jupiter's swarms of Trojan asteroids may be remnants of the primordial material that formed the outer planets, and serve as time capsules from the birth of our Solar System more than 4 billion years ago. The Trojans orbit in two loose groups that orbit the Sun, with one group always ahead of Jupiter in its path, the other always behind. At these two Lagrange points the bodies are stabilized by the Sun and Jupiter in a gravitational balancing act. These primitive bodies hold vital clues to deciphering the history of the solar system, and perhaps even the origins of life and organic material on Earth.
Lucy will be the first space mission to study the Trojans. The mission takes its name from the fossilized human ancestor (called “Lucy” by her discoverers) whose skeleton provided unique insight into humanity's evolution. Likewise, the Lucy mission will revolutionize our knowledge of planetary origins and the formation of the solar system.
Lucy will launch in October 2021 and, with boosts from Earth's gravity, will complete a twelve-year journey to eight different asteroids — a Main Belt asteroid and seven Jupiter Trojans, the last two members of a “two-for-the-price-of-one” binary system. Lucy’s complex path will take it to both clusters of Trojans and give us our first close-up view of all three major types of bodies in the swarms (so-called C-, P- and D-types).