The Lucy logo says "first to the Trojan asteroids. It features an outline of the Lucy skeleton, the spacecraft and Trojan asteroids in the backgorund.

Lucy

The first mission to explore the Jupiter Trojan asteroids.

active Mission
Artist's concept of the Lucy orbiter with its distinctive round solar panels as it flies past a Trojan asteroid near Jupiter.

Lucy will explore a record-breaking number of asteroids, flying by three asteroids in the solar system’s main asteroid belt, and by eight Trojan asteroids that share an orbit around the Sun with Jupiter.

Mission Type

Asteroid flybys

Number of Asteroids

11

Launch

Oct. 16, 2021

Next flyby

April 20, 2025

Overview

Lucy is the first space mission to explore a diverse population of small bodies known as the Jupiter Trojan
asteroids. These remnants of our early solar system are trapped on stable orbits associated with – but not close to – the giant planet Jupiter. Trojan asteroids orbit in two “swarms” that lead and follow Jupiter in its orbit around the Sun and are thought to be comparable in number to the objects in the main asteroid belt between the orbits of Mars and Jupiter.

Over its 12-year mission, Lucy will explore a record-breaking number of asteroids: it will fly by three in the belt of asteroids that circle the Sun between the orbits of Mars and Jupiter, and then eight Trojans, which includes five asteroid targets and the satellites of three of those. Lucy also will fly by Earth three times to get a push from its gravity, making it the first spacecraft to return to the vicinity of Earth from the outer solar system.

Lucy is named for a fossilized skeleton of a human ancestor, which was named for the Beatles song "Lucy in the Sky with Diamonds."

Asteroid
Flyby Date
Dinkinesh (pronounced DIN-ke-nesh) and a contact binary satellite Selam (SEY-lahm)
Nov. 1, 2023
Donaldjohanson
April 20, 2025
Eurybates (yoo-RIB-a-teez or you-ri-BAY-teez)
and its satellite Queta (KEH-tah)
Aug. 12, 2027
Polymele (pah-li-MEH-lee or pah-LIM-ah-lee)
and its unnamed satellite
Sept. 15, 2027
Leucus (LYOO-kus or LOO-kus)
April 18, 2028
Orus (OH-rus)
Nov. 11, 2028
Patroclus (pa-TROH-klus) and its satellite
Menoetius (meno-EE-shus or meh-NEE-shus)
March 3, 2033

The Lucy mission is named after the fossilized skeleton of an early hominin (pre-human ancestor) that was found in Ethiopia in 1974 and named “Lucy” by the team of paleoanthropologists who discovered it. And just as the Lucy fossil provided unique insights into human evolution, the Lucy mission promises to expand our knowledge of planetary origins.

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