The Dawn Mission is a NASA unmanned space mission that will send an orbiting space probe to examine the asteroids Ceres and Vesta. Dawn will be the first mission to enter into orbit around two different planetary bodies other than the Earth and Moon.

The mission's goal is to characterize the conditions and processes of the solar system's earliest epoch by investigating in detail two of the largest protoplanets remaining intact since their formation. Ceres and Vesta have many contrasting characteristics that are thought to have resulted from them forming in two different regions of the early solar system; Ceres is theorized to have to have experienced a "cool and wet" formation that may have left it with subsurface water, and Vesta is theorized to have experienced a "hot and dry" formation that resulted in a differentiated interior and surface vulcanism.

Dawn will be launched on a Delta 7925H rocket. To cruise from Earth to its targets it will use three DS1 heritage Xenon ion thrusters (firing only one at a time) to take it in a long outward spiral. The planned chronology is:

• Launch on May 27, 2006
• Vesta arrival July 30, 2010
• Vesta departure July 3, 2011
• Ceres arrival August 20, 2014
• End of operations July 26, 2015

An extended mission in which Dawn explores other asteroids after Ceres is also possible.

The Dawn mission team is led by UCLA space scientist Christopher T. Russell . Orbital Sciences Corporation will construct the spacecraft, and NASA's Jet Propulsion Laboratory will provide the ion engines and management of the overall flight system development. The German Aerospace Center will provide the framing camera, and the Institute for Space Astrophysics in Rome will provide the mapping spectrometer. A laser altimeter will be provided by the NASA Goddard Space Flight Center, a gamma ray spectrometer from the DOE Los Alamos National Laboratory, and a magnetometer will be provided by UCLA.

External links

• Dawn Mission homepage