NASA’s Lucy Spacecraft Tests Cameras Ahead of 2027 Trojan Flybys

NASA’s Lucy spacecraft has photographed four Jupiter Trojan asteroids — Eurybates, Polymele, Leucus, and Orus — from hundreds of millions of miles away, testing its camera settings ahead of its first close flybys, which begin in August 2027. The images were captured this spring with Lucy’s high-resolution L’LORRI camera, and the mission team finished downlinking and processing them in July 2026.

Pinpricks of Light, for Now

From Lucy’s current distance, all four asteroids appear as little more than points of light against a dense field of background stars. That is expected: the spacecraft is still hundreds of millions of miles from its targets. But the faint observations serve a specific purpose. They let mission scientists select the camera settings that will capture usable surface detail once Lucy is close enough to see real terrain, rather than a single pixel of reflected sunlight.

The spacecraft will fly past all four asteroids between August 2027 and November 2028, coming within 300 to 600 miles at closest approach while moving at speeds up to 16,000 mph. Two of the four targets have small moons of their own, adding further complexity to each encounter.

A Different Angle Than Any Telescope on Earth

The spring observations matter because Lucy, nearly five years into its journey, now sees the Trojans from a viewing angle no Earth-based telescope can match. Astronomers on the ground typically observe the Trojans from roughly the same direction as the Sun, so the asteroids appear almost fully illuminated, similar to a full Moon. Lucy’s flybys will look nothing like that. Approaching from a different angle, the spacecraft will see each asteroid’s surface partly in shadow.

Testing the cameras under lighting conditions that approximate what Lucy will actually encounter during the flybys helps the team avoid two failure modes: images that are too dark to reveal surface features, or images so overexposed that the detail washes out. Getting the exposure right matters because there is no second chance — each flyby happens once, at high speed, with no opportunity to retake an image.

What the Trojan Asteroids Can Reveal

The Trojan asteroids orbit the Sun in two loose swarms that share Jupiter’s orbit, though the objects themselves are not near the planet. Lucy is the first mission NASA has selected to study Trojan asteroids up close. According to the mission team, these primitive bodies hold vital clues to deciphering the history of the solar system, which is part of why Lucy was designed to visit eight of them over its 12-year flight.

Lucy’s Twelve-Year Journey

Lucy launched in October 2021 and is on a 12-year trajectory that will carry it past eight Trojan asteroids in total. The mission is managed by NASA’s Goddard Space Flight Center, with the Southwest Research Institute leading the science investigation and Johns Hopkins University’s Applied Physics Laboratory contributing to spacecraft operations. The L’LORRI (Long Range Reconnaissance Imager) instrument used for these test observations is the same high-resolution camera Lucy will rely on during each flyby to capture visible and infrared imagery, along with other science data, as it passes each target.

What Comes Next

As Lucy continues toward the outer solar system, the mission team will have additional opportunities to observe these four asteroids before the actual encounters begin. The team specifically plans to gather more images of Orus, whose motion was less visible in the spring data because Lucy imaged it over a shorter time span than the other three targets, before the spacecraft’s flyby of that asteroid in November 2028.

The camera tests are a small but necessary step in a mission built around one-time, high-speed encounters with objects that have never been seen up close. Trojan asteroids are believed to hold some of the most primitive material left over from the solar system’s formation, and Lucy’s eight flybys represent the first sustained opportunity to examine that material directly, rather than through the blur of reflected sunlight seen from Earth.

Source: NASA — Goddard Space Flight Center / Lucy Mission (Southwest Research Institute, science lead). Primary source: science.nasa.gov/blogs/lucy.