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if all goes as planned 32 we have main

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engine start in the summer of 2007 and

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lift on a delta 2 rocket who carried on

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when that dawn spacecraft lifts off and

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we're on our way to finding out about

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some of the biggest mysteries in the

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solar system that's something we can all

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be part of its so cool going to the

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asteroid belt this ring of broken up

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debris between Mars and Jupiter these

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are among the last unexplored worlds in

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the inner solar system the asteroid belt

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is really fascinating because it's kind

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of like the bone yard of material that's

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left over from forming all these planets

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its fragments of explosions of planetary

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embryos perhaps during collisions or

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material that's come in from other parts

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of the solar system and been captured

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into this orbit of the asteroid belt

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we're going out to series and also to

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Vesta and these are very different

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bodies Vesta is the brightest asteroid

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in the solar system and the only one

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visible to the naked eye in one sense

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it's sort of like our moon but in

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another sense that's sort of like the

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earth it's got a iron core just like the

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earth does and it may have had many of

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the processes acting that the earth has

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the three science instruments on dawn

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all work together to tell us about the

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surfaces of the body and from that we we

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try to work back to you know how the

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whole thing was put together and what

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happened to it

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scientists believe series represents a

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transition from the rocky terrestrial

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planets of the inner solar system should

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be dashes and icy worlds of the outer

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solar system series likely has a rocky

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core and a very thick ice mantle there's

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even the possibility that there's liquid

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water under the surface of Ceres we

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estimated from our measurements with

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Hubble Space Telescope that it's got

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almost a hundred kilometers of water on

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top of a rocky core to accomplish danza

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journey into the heart of the asteroid

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belt the spaceship one whose engine will

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work without fail for years at a time is

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required Dawn's remarkable ion engines

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employ electrical currents magnetic

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fields and xenon the high-tech innards

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of an ion engine change the xenon into a

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positively charged plasma and

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accelerated out the engine at speeds

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over 78,000 miles per hour the ion

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engine pushes on the spacecraft about as

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hard as the single piece of paper pushes

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on my hand but this very gentle thrust

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eventually builds up and allows the

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spacecraft to achieve very very high

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speed with the ion propulsion system

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dawn will be the first spacecraft ever

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to orbit to target bodies after leaving

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Earth a mission into our distant past a

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mission for the future a mission into