Lucy mission to Trojan asteroids: 5 years of discoveries

NASA’s Lucy mission is now less than a year from reaching the Trojan asteroids near Jupiter. And it has already made some exciting discoveries along the way. The science-journalism coverage adds useful context, while the strongest evidential footing still comes from the underlying data, papers or institutional documentation.

It is relevant because Earth science becomes stronger when local observations can be placed inside a broader physical pattern that spans time and geography. The planet operates as a coupled system in which atmospheric, oceanic, cryospheric and solid-Earth processes interact across timescales from days to millions of years. A measurement that captures one variable at one location and one moment has limited interpretive value until it is embedded in the longer series and wider spatial coverage that allow natural variability to be separated from forced change. 5 years into the Lucy mission NASA’s Lucy spacecraft is getting ever closer to its destination, the Trojan asteroids. Lucy is an ambitious NASA mission, with plans to visit 11 asteroids in its 12-year mission to tour the Trojan asteroids that are located in two swarms leading and trailing Jupiter.

Back in 2022, the mission team found that Lucy would come close to the asteroid, which was still unnamed at the time. The Lucy mission took this image a few minutes after closest approach to asteroid Dinkinesh on November 1, 2023.

We clearly see the asteroid’s double moon, Selam, on the right, as 2 smaller bodies stuck together. The asteroid also wobbles, rotating end-over-end once every 10.5 Earth days while rolling around its lateral axis once every 26.5 days.

This is asteroid Donaldjohanson as NASA’s Lucy spacecraft saw it during a flyby on April 20, 2025. Lucy passed only 220 miles (350 km) above the surface of Earth.

The broader interest lies in linking the observation to climatic, geophysical or environmental dynamics that extend well beyond the immediate event or location. Earth science is unusual in that its most important questions operate on timescales that no single research career can observe directly, making the archival record, whether in ice, sediment, rock or satellite data, as important as any new measurement. Results that can be embedded in that record, and that either confirm or challenge the patterns it reveals, carry disproportionate scientific weight.

Lucy will make yet another Earth flyby in December 2030. NASA Lucy spacecraft’s 2nd Earth gravity assist dramatically alters the spacecraft’s trajectory, enabling it to travel through the Jupiter Trojan asteroids.

Because this item comes through EarthSky as science journalism, it should be treated as contextual reporting rather than primary evidence. Good science reporting can identify why a result matters, connect it to the wider literature and make technical work readable, but the decisive evidence remains in the original paper, dataset, mission release or technical record. That distinction is especially important when a story is later repeated by aggregators, because repetition increases visibility, not evidential strength.

The next step is to place the result inside longer time series and to compare it with independent instruments and independent sites. Earth system observations gain most of their interpretive power from network density and temporal depth, not from any single measurement however precise. Model simulations that assimilate the new data will help clarify whether the observation fits comfortably within known natural variability or represents a shift that existing models do not reproduce.

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