The spacecraft Lucy has entered the region of Trojan asteroids that travel ahead of Jupiter around the Sun, five years after launch. Lucy’s first close encounter remains planned for August 2027. The milestone brings the spacecraft nearer to a population that could help test ideas about the early Solar System, with measurements still ahead.
Lucy has reached the region occupied by Trojan asteroids that move ahead of Jupiter along its orbit around the Sun. NASA announced the milestone on October 28, after about 3.5 billion kilometers of travel since the spacecraft’s October 2021 launch. The arrival is a new geographic phase in a mission designed to study these primitive Solar System objects.[1], [2]
Trojan asteroids occupy two broad regions associated with Jupiter’s orbit, one ahead of the planet and the other behind it. The objects are separated by millions of kilometers. Lucy’s first close encounter, with Eurybates, is planned for August 11, 2027. NASA then plans visits to Polymele in September 2027, Leucus in April 2028 and Orus in November 2028.[1]
A 2030 Earth gravity assist would send Lucy toward the trailing Trojan group for a March 2033 encounter with Patroclus and Menoetius. NASA says the spacecraft and instruments are operating normally in the dimmer sunlight of deep space. The planned close-up measurements could constrain ideas about planetary formation. Entering the Trojan region itself has not yet supplied surface observations of the targets.[1]
