Exploring the Trojan Asteroids

An artist illustration of the Lucy spacecraft.
An artist illustration of the Lucy spacecraft. Image credit: NASA

During its 12-year mission, NASA’s Lucy spacecraft will explore eight asteroids. It will explore more asteroids than any previous mission. On its way out to the Trojan asteroids, Lucy will fly by the main belt asteroid (52246) Donaldjohanson on April 20, 2025. There, Lucy will fly by five of these L4 Trojans: Eurybates and its satellite, Queta, on Aug. 27, 2027, Polymele on Sept. 15, 2027, Leucus on April 18, 2028, and Orus on Nov. 11, 2028.

The spacecraft’s orbit will then bring Lucy back to the vicinity of the Earth for another gravity assist, and will take it again out to the distance of Jupiter. Arriving on March 2, 2033, Lucy will fly by Patroclus and its near-twin binary companion Menoetius. While the flyby of this remarkable asteroid pair will be the expected finale of the mission. Lucy will remain on a stable orbit which will enable it to visit the Trojan swarms over and over again for many thousands, and possibly millions, of years.