Lucy reaches the Trojans' region, with close encounters still ahead
· BehindLines newsroom
NASA announced on 28 October that Lucy had reached the region of Jupiter's Trojan asteroids. The milestone comes five years after its launch on 16 October 2021. Entering this vast area does not, however, mean the spacecraft has already taken close-up images of the objects it is to study.
A region without a marked boundary
These asteroids share Jupiter's orbit around the Sun in two groups, ahead of and behind the planet. Lucy is approaching the first group, around the L4 Lagrange point. NASA notes that this region has no sharply defined spatial boundary.
Tracking radio signals and images of stars allows engineers to locate the spacecraft. According to NASA, the targets still appear as points of light; their close flybys remain ahead.
Earlier encounters have already yielded observations
The Southwest Research Institute, which leads the mission's scientific work, recalled several earlier encounters in the main asteroid belt in its 19 October review.
The November 2023 flyby of Dinkinesh revealed its satellite Selam, itself made of two parts in contact. In April 2025, Lucy then observed Donaldjohanson, another object with two lobes. According to SwRI, these passages allowed the spacecraft's navigation to be tested before the Trojan encounters.
The next appointments
According to NASA's 28 October update, the first Trojan flyby, of Eurybates, is scheduled for 11 August 2027. The timetable then includes Polymele in September 2027, Leucus in April 2028 and Orus in November 2028.
Another Earth gravity assist, scheduled for 2030, is intended to send Lucy towards the other group to encounter Patroclus and Menoetius in March 2033. The programme thus covers several systems, comparing objects that could shed light on planet formation, according to the mission teams. The current announcement marks a step along the journey; the main scientific flybys are still to come.