The moon discovered by NASA’s Lucy mission during its initial collision with the asteroid has an official name. On November 27, 2023, the International Astronomical Union approved the name “Salam” or سلام, meaning “earth” in Ethiopian (Amharic) for Dinkinesh’s moon.

“Dinkinesh is the Ethiopian name for a fossil nicknamed ‘Lucy,'” says Raphael Marshall of the Côte d’Azur Observatory in Nice, France, who first identified Dinkinesh as a potential target for the Lucy mission. name her companion after another fossil, sometimes called Lucy’s baby.” The Selam fossil, discovered by Zeresenai Alemseged in Dikita, Ethiopia, in 2000, belonged to a three-year-old female of the same species as Lucy, though the “child” actually predated Lucy by 100,000 years. had lived.

The Lucy spacecraft flew past Dinkinesh and Selam on November 1, 2023. Although pre-encounter observations suggested something interesting was going on in this system, the team was surprised to discover that Dinkinesh not only had a satellite, but that it was also a contact binary satellite, the first binary contact satellite ever observed.

The team has completed data transfer from Lucy’s first collision with an asteroid and is continuing to process it. The Dinkinesh rendezvous was added in January this year as a flight test of the spacecraft’s systems and instruments, and all systems performed well.

The tools and techniques developed with the data from this encounter will help the team prepare for the mission’s main targets: Jupiter’s never-before-discovered Trojan asteroids. In addition to images taken by Lucy’s high-resolution L’LORRI camera and Terminal Tracking Cameras (T2Cam), Lucy’s other science instruments also collected data that will help scientists understand these mysterious asteroids.

Two components of the L’Ralph instrument provided by Goddard – the Multispectral Visible Imaging Camera (MVIC) and the Line Reference Imaging Spectral Array (LEISA) – successfully observed two asteroids from different vantage points in the closest approach zone. During the rendezvous, the two components scanned the surfaces of the asteroids, allowing the team to collect spatially resolved color images and spectra of the objects.

“We must carefully evaluate the spacecraft’s motion to collect the final images, but Lucy’s precise orientation information makes this possible,” said Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These images will help scientists understand the composition of asteroids, allowing the team to compare the composition of Dinkinesh and Selam and understand how these objects may be compositionally related to other asteroids.”

Arizona State University’s Lucy Thermal Emission Spectrometer (L’TES) also detected asteroids; but unlike future Trojan asteroid targets, they filled only a small portion of the device’s wide field of view. Scientists hope that these data will mainly provide insight into the surface features of the larger Dinkinesh asteroid.

“L’TES was able to detect and measure the temperature of the system for approximately nine minutes while the spacecraft was at closest approach,” said Phil Christensen of Arizona State University in Tempe. “Different sized fragments, such as sand, pebbles, and rocks, heat differently as the asteroid rotates. L’TES temperature measurements will allow us to study the size and physical properties of materials on the asteroid’s surface.”

Over the next decade, Lucy is expected to visit 9 more asteroids in 6 separate encounters. After Earth’s gravitational pull in December 2024, the spacecraft will return to the main asteroid belt, where it will rendezvous with asteroid Donald Johanson in April 2025. Lucy will pass through the main belt in 2027 and reach the mission’s primary targets (Jupiter’s Trojan asteroids).