NASA’s Lucy spacecraft sees first-ever Contact Binary orbiting asteroid

NASA Lucy spacecraft continues to amaze scientists following its first asteroid encounter on November 1, 2023. The mission team has now discovered that asteroid Dinkinesh’s unanticipated satellite is a contact binary - meaning, it is made of two smaller objects touching each other. This is the first time a contact binary has been seen orbiting another asteroid.

The first images downlinked after Lucy's flyby of Dinkinesh show that the two lobes of the contact binary lie one behind the other from the spacecraft's point of view. Additional images captured in the minutes around the close approach revealed the true nature of this object, NASA said on Tuesday.

"Contact binaries seem to be fairly common in the solar system. We haven’t seen many up-close, and we've never seen one orbiting another asteroid," said John Spencer, Lucy deputy project scientist, of the Boulder, Colorado, branch of the San-Antonio-based Southwest Research Institute.

Lucy, you’ve surprised us againNew images from the #LucyMission’s first asteroid flyby show that a satellite, already unexpected, is made of two objects – a contact binary. This is the first time we’ve seen a contact binary orbiting another asteroid. https://t.co/NwQfI6k7qz pic.twitter.com/WTSHNLyr86

— NASA Solar System (@NASASolarSystem) November 7, 2023

Lucy is on a mission to survey the never-before-visited Jupiter Trojan asteroids mysterious space rocks that have been gravitationally trapped in Jupiter's orbit around the Sun for billions of years and hold clues to the formation of our solar system.

Asteroid Dinkinesh and its satellite are the first two of 11 asteroids that Lucy is planning to explore over its 12-year journey. The spacecraft is currently heading back toward Earth for a gravity assist in December 2024. That close flyby will propel the spacecraft back through the main asteroid belt, where it will observe asteroid Donaldjohanson in 2025, and then on to the Trojan asteroids in 2027.