Abstract
Lucy is a NASA Discovery-class mission to send a highly capable and robust spacecraft to investigate primitive bodies near both the L(4) and L(5) Lagrange points with Jupiter; the Jupiter Trojan asteroids. This heretofore unexplored population of planetesimals from the outer planetary system holds vital clues to deciphering the history of the Solar System. Due to an unusual and fortuitous orbital configuration, Lucy will perform a comprehensive investigation that visits eight Trojans, including all the recognized taxonomic classes, a collisional family member and a near equal-mass binary. It will visit objects with diameters ranging from roughly 1 to 100 km. In particular, Lucy will perform flybys of (3548) Eurybates and its satellite Queta (L(4), C-type), (15094) Polymele and its currently unnamed satellite (L(4), P-type), (11351) Leucus (L(4), D-type), (21900) Orus (L(4), D-type), and the (617) Patroclus-Menoetius binary (L(5), P-types). This diverse array of targets will supply invaluable constraints on the formation and early dynamical evolution of the giant planets. In addition, Lucy will visit two main-belt asteroids, (152830) Dinkinesh and (52246) Donaldjohanson, in order to practice its encounters. Lucy's payload suite consists of a color camera and infrared imaging spectrometer, a high resolution panchromatic imager, and a thermal infrared spectrometer. Additionally, two spacecraft subsystems will also contribute to the science investigations: the terminal tracking cameras will supplement imaging during closest approach and the telecommunication subsystem will be used to measure the mass of the Trojans. Lucy launched on October 16, 2021 and will have encounters with the Trojans from August 2027 until March 2033.