From the November 2015 issue

Web Extra: Dawn explores the biggest asteroids

Before heading for Ceres, NASA’s Dawn spacecraft spent 14 months learning about its rockier neighbor, Vesta.
By | Published: November 23, 2015 | Last updated on May 18, 2023
Astronomers believe the troughs around Vesta’s equator are shock-like remnants of ancient impacts. These features could not have formed if the asteroid did not have separate core, mantle, and crust layers.
By the time NASA’s Dawn mission reached the dwarf planet Ceres in March 2015, it had already accomplished as much as is typically expected in the lifetime of an average spacecraft. But Dawn is not an average spacecraft.

The interplanetary voyager launched in 2007 and used ion propulsion to wind its way across the solar system, building up speed with a gravity assist from Mars in 2009.

This approach to exploration allowed the Dawn team to study the asteroid Vesta for 14 months before departing for Ceres. And at Vesta it helped decipher clues about the rocky body’s history of collisions.

Former Associate Editor Sarah Scoles wrote about Dawn’s finds there for Astronomy’s special issue on space rocks in March 2014.

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