NASA Lucy mission makes surprise asteroid discovery

A NASA spacecraft set to explore more asteroids than any other space mission has made an early, surprise discovery as it charts a path towards Jupiter.

The Lucy mission was launched in 2021 and will explore a set of asteroids known as the 10 Trojans over 12 years. These objects share Jupiter’s orbit around the Sun but aren’t close to the gas giant.

With its first flyby of the asteroid Dinkinesh in the asteroid belt between the orbits of Mars and Jupiter, Lucy discovered it is not one single 790m-wide asteroid, but a system of two, with a small 220m-wide satellite spinning around it.

A series of images of the binary asteroid pair, Dinkinesh, as seen by the terminal tracking camera (T2CAM) on NASA’s Lucy spacecraft
A series of images of the binary asteroid pair, Dinkinesh, as seen by the terminal tracking camera (T2CAM) on NASA’s Lucy spacecraft taken on Nov. 1, 2023. Credit: NASA/Goddard/SwRI/ASU

Images beamed to NASA’s mission control show the two objects spinning in space as Lucy zipped past at 16,000km/h.

Lucy’s project team is pleased with the initial performance of the Dinkinesh flyby. It was added to the mission’s schedule as an engineering test before reaching its primary targets over the following decade: if Lucy’s terminal tracking system could capture, at speed, clear pictures – which in astronomical terms is a couple of hundred pixels wide using the best cameras mounted to the spacecraft – then its project team could sleep a little easier.

“This is an awesome series of images,” says Lucy’s guidance and navigation engineer Tom Kennedy, based at Lockheed Martin in Colorado.

Lockheed Martin built the 16m-long spacecraft. The mission is being run out of NASA’s Goddard Space Flight Centre, with a separate investigation team at the Southwest Research Institute in Colorado.

“They indicate that the terminal tracking system worked as intended, even when the universe presented us with a more difficult target than we expected,” Kennedy says.

It’s one thing to simulate, test, and practice. It’s another thing entirely to see it actually happen.”

The “moonrise” of the satellite as it emerges from behind asteroid Dinkinesh as seen by the Lucy Long-Range Reconnaissance Imager (L’LORRI), one of the most detailed images returned by NASA’s Lucy spacecraft during its flyby of the asteroid binary.
The “moonrise” of the Dinkinesh satellite as it emerges from behind the larger asteroid, captured by L’LORRI. Credit: NASA/Goddard/SwRI/Johns Hopkins APL/NOAO

Lucy’s best camera is named L’LORRI (short for Lucy Long Range Reconnaissance Imager), a camera based on the design of the Hubble Space Telescope’s lens. It’s panchromatic, meaning it can capture light across the entire visible spectrum, and delivers clear images of craters at a distance of 1,000km. NASA describes L’LORRI’s performance as like standing at one end of a playing field and clearly seeing a fly at the other.

Lucy was as close as 430km from Dinkinesh when it took its snaps. It’s now on course to reach its next target – the belt asteroid ‘52246 DonaldJohanson’ in April 2025 before beginning its journey to the Jupiter Trojans.

Its first Trojan targets are Eurybates and Queta (August 2027), followed by Polymele (September 2027), Leucus (April 2028), Orus (Nov 2028), and finally Patroclus and Menoetius (March 2033).

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