Lucy will explore the Jupiter Trojan asteroids. During its 12-year mission, the spacecraft will explore a record-breaking number of asteroids, flying by one main belt asteroid and seven Trojan asteroids. These small bodies are remnants of our early solar system, now trapped in stable orbits associated with – but not close to – the giant planet Jupiter. The Trojan asteroids are in two “swarms” that lead and follow Jupiter in its orbit around the Sun and are almost as numerous as the objects in the Main Asteroid Belt. Lucy also will circle back to Earth three times for gravity assists, making it the first spacecraft ever to return to the vicinity of Earth from the outer solar system.
The Lucy mission is named after the fossilized skeleton of an early hominin, or pre-human ancestor, that was found in Ethiopia in 1974 and named “Lucy,” by the team of paleontologists who discovered it.
Lucy has the following science objectives at each of its destinations:
- Surface Geology – Lucy will map the shape, albedo, and crater spatial and size-frequency distributions; determine the nature of crustal structure and layering; and determine the relative ages of surface units
- Surface Color and Composition – Lucy will map the color, composition and regolith properties of the surface, and determine the distribution of minerals, ices, and organic species
- Interiors and Bulk Properties – Lucy will determine the masses and densities, and study sub-surface composition via excavation by craters, factures, ejecta blankets, and exposed bedding.
- Satellites and Rings – Lucy will look for and study satellites and/or rings that might orbit the targeted Trojan asteroids.