What did the Dawn spacecraft discover about Vesta?

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Illustration showing a massive asteroid above a city map with a dinosaur silhouette for scale, highlighting the asteroid's size compared to major urban areas. — Asteroid This rock would take out more than just a *T. rex*.

The Dawn spacecraft’s mission to Vesta provided significant insights into the nature of this body, confirming that it is a protoplanet rather than a simple asteroid.1

Key discoveries include:

Internal Structure: Unlike typical asteroids, Vesta possesses a differentiated internal structure, including an iron core measuring between 214 and 226 km (133 and 140 miles) in diameter.1
Surface Features: High-resolution imagery revealed extensive sets of grooves known as fossae, such as the Divalia Fossa, which extends more than halfway around the equator. The surface also features numerous impact craters, including a distinctive "snowmanlike" arrangement of three craters named Marcia, Calpurnia, and Minucia.1
Meteorite Origin: Spectral analysis confirmed that Vesta is the source of howardite-eucrite-diogenite (HED) meteorites discovered on Earth.1
Composition: Through the use of gamma-ray and neutron spectrometers, the mission measured the abundance of key elements such as oxygen, silicon, iron, and calcium, providing a detailed look at the chemical makeup of this planetary body.1