NASA’s Lucy spacecraft is set for its second asteroid encounter, this time with the small main belt asteroid Donaldjohanson. The spacecraft will pass within 596 miles of Donaldjohanson on April 20 at 1:51 pm EDT. During the flyby, Lucy’s instruments will be used to observe the asteroid and gather data. This event is a “dress rehearsal” for the mission’s main goal: exploring multiple Trojan asteroids in Jupiter’s orbit.
Lucy’s first encounter with Dinkinesh, a tiny main belt asteroid, provided valuable systems testing experience. The upcoming flyby of Donaldjohanson will build on this success and use more complex observing sequences than previously used. However, to protect its sensitive instruments from intense sunlight, Lucy will stop tracking the asteroid 40 seconds before closest approach.
The spacecraft’s journey to the asteroid is not without challenge due to its vast distance – 12.5 light minutes away from Earth – and slow communication speeds. It takes 25 minutes for a signal to be sent from Earth and receive a response from Lucy, making real-time communication impossible.
Donaldjohanson is one of the youngest main belt asteroids ever visited by a spacecraft, with a history dating back to a collision 150 million years ago. Each asteroid encounter brings new insights into our solar system’s history, and NASA scientists are eager to uncover the secrets that Donaldjohanson holds. The upcoming flyby promises to be an exciting event, with unexpected discoveries waiting to be made.
Source: https://phys.org/news/2025-04-lucy-spacecraft-asteroid-encounter.html