Welcome to the Party!

Why are we here?

• Celebrate the beginning of Dawn's year-long exploration of new worlds!

• Share in the excitement as we see something no one has seen before!

• Learn something new!

Dawn: Exploring New Worlds

DAWN Mission

Dawn EPO Teams

• So why did Dawn’s scientists want to look at the asteroid belt? To explore the earliest stage of our solar system To understand how planets like ours formed!

• Use ion propulsion to explore two asteroids protoplanet Vesta and Dwarf Planet Ceres, by:Mapping their surfaces to learn their geology & compositionDetermining how and when they formedAnd learning the internal and external forces that shaped them

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What will the Dawn Spacecraft do?

Why Ceres and Vesta?

• Vesta and Ceres are among the largest asteroids and survivors of the formation of the solar system

• Vesta was volcanically active like our moon, while Ceres is made of ice and rock like Jupiter’s moons

• Studying Ceres & Vesta together tells us about how a planet’s size and distance from the sun affect its formation

What is an asteroid, really?• There isn’t a good

definition

• Generally, a small, rocky body orbiting ~inside the orbit of Jupiter

• Most are found in the main belt between Mars & Jupiter (which looks something like this) -->

Image credits: NASA/JPL

What are Asteroids

made of?• Bright, dry, rocky

asteroids like Vesta dominate the inner asteroid belt

• Dark, hydrated, and icy asteroids like Ceres dominate the outer belt

• Ceres and Vesta are big enough to differentiate (have a core like the Earth), and thus are also called “protoplanets”

Asteroids come in all shapes & sizes, but protoplanets are nearly round!

950 km

Ceres

Vesta

Pallas

Ida

Gaspra

Annefrank

Itokawa

Eros

Image credits: NASA & STScI (HST)

What do we know about Vesta?• Discovered by Heinrich

Olbers in March 1807• Named after the Roman

goddess of the hearth• Largest basaltic asteroid 265 km average radius Third largest asteroid! Second most massive• Differentiated Basaltic (like Hawaii’s

volcanoes) Distinct surface regions Implies early formation

Image credit: STScI (HST)

What do we know about Ceres?• Discovered in 1801 by

Piazzi• Named after the Roman

goddess of agriculture• Largest and brightest

body in asteroid belt Average radius of 950 km• Because: It has no obvious surface

features We have no meteorites from it! • …it’s probably made of ICE!

Image credit: STScI

At each target, Dawn will:• Acquire color images• Compile a topographic map• Map the elemental composition• Map the mineralogical composition• Measure the gravity field• Search for moons

Where is Dawn going?

LaunchSep 2007

Mars Gravity AssistFeb 2009

VestaJuly 2011 – July 2012

CeresFeb 2015 – July 2015

Explore Vesta using its specialized instrumentation.

• Composition will be mapped by Visual Infrared Spectrometer (VIR) and Framing Camera color filters

• Topography, impact history and geology will be mapped by the Framing Camera

• Elemental abundances will be determined by GRaND

• Crustal thickness and interior structure will be determined by gravity from radio science

What will Dawn do at Vesta?(Jul ‘11- Jul ‘12)

Any Questions?

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Dawn’s Launch, Sept. 27 2007

Visit: dawn.jpl.nasa.gov