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 & composition  Determining how and when they formed  And learning the internal and external forces that shaped them 3 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? Launch Sep 2007 Mars Gravity Assist Feb 2009 Vesta July 2011 – July 2012 Ceres Feb 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? 12 Dawn’s Launch, Sept Visit: dawn.jpl.nasa.gov