NASA’s Lucy spacecraft is preparing for its first close look at an asteroid. It will fly past the Dinkinesh asteroid on November 1 and test its instruments in preparation for visits to several Trojan asteroids orbiting the Sun in the same orbit as Jupiter over the next decade.

Located less than half a mile, or 1 kilometer, away, Dinkinesh orbits the Sun in the main asteroid belt located between the orbits of Mars and Jupiter. Lucy has been visually tracking Dinkinesh since September 3; This will be the first of 10 asteroids that Lucy will visit during its 12-year journey. To observe so many asteroids, Lucy will not intercept or orbit asteroids, but instead collect data by flying past them in a method known as a “flyby.”

“Lucy will give us the first up-close look at an object that until now has remained an unresolved dot in the best telescopes,” said Hal Levison, Lucy’s principal investigator at the Southwest Research Institute based in San Antonio. “Dinkinesh is about to reveal himself to humanity for the first time.”

The main goal of the Lucy mission, launched on October 16, 2021, is to study Jupiter’s Trojan asteroids; it is a never-before-discovered collection of small objects orbiting the Sun in two “swarms” that guide and follow Jupiter into its orbit. But before reaching the Trojans, Lucy will fly past another main-belt asteroid called Donald Johanson in 2025 for additional testing of the spacecraft’s systems and procedures.

During the Dinkinesh flyby, the team will test the terminal tracking system, which will allow the spacecraft to autonomously locate the asteroid and keep it in line of sight with the instruments throughout the encounter.

Since the purpose of this rendezvous is to test Lucy’s systems, scientific observations will be simpler than the primary mission objectives. The platform housing the spacecraft and instruments will be in place two hours before closest approach to Dinkinesh. Once in place, the spacecraft will begin collecting data with its High Resolution Imaging Spectrophotometer (L’LORRI) and Thermal Infrared Imager (L’TES).

One hour before closest approach, the spacecraft will begin tracking the asteroid using its terminal tracking system. Lucy will only be able to collect data for the last eight minutes using MVIC and LEISA, a color imager and infrared spectrometer that are part of the L’Ralph instrument. Lucy is expected to make its closest approach at 12:54 ET, when the spacecraft will approach within 430 kilometers of the asteroid. Lucy will continue to visualize and follow Dinkinesh for almost another hour. The spacecraft will then change course to re-establish contact with Earth, but will continue to take periodic images of Dinkinesh with L’LORRI over the next four days.

“We will know what the spacecraft is supposed to be doing at any given time, but Lucy is so far away that a radio signal takes about 30 minutes to travel between the spacecraft and Earth, so we can’t interactively control the encounter with the asteroid,” he said. Mark Effertz is Lucy’s chief engineer at Lockheed Martin Space in Littleton, Colorado. “Instead, we will pre-schedule all scientific observations. After completing the scientific observations and flyby, Lucy will re-orient its high-gain antenna towards Earth, and it will then take almost 30 minutes for the first signal to reach Earth.”

After verifying that the spacecraft is safe, engineers will order Lucy to send scientific data about the rendezvous to Earth. This data will take a few days. While the primary purpose of the Dinkinesh encounter is an engineering test, mission scientists also hope to use the data to gain insight into the relationship between larger main belt asteroids and smaller near-Earth asteroids studied by previous NASA missions.

Following the Dinkinesh encounter, the Lucy spacecraft will continue its orbit around the Sun and return to Earth for its second gravity boost in December 2024. This push from Earth will send it back to the main asteroid belt for the Donaldohanson flyby in 2025, and then to Jupiter’s Trojan asteroids in 2027. Source