Mission Objectives Overview  ===========================The specific Dawn science objectives by instrument are as follows.Framing Camera--------------1. To determine the origin and evolution of Vesta and Ceres by mappingthe extent of geologic processes on the asteroid surfaces, and by usingthe cratering record to establish a relative chronology of the crustalunits and population of impactors in the early solar system.2. To map the shape, determine the spin state, and establish the degreeof cratering of the asteroids visited.3. To map the topography of Vesta and Ceres.4. To search for dust and satellites in the environment of theasteroids visited.5. To provide a geologic, compositional and geophysical context forthe HED meteorites.6. To provide an opportunity to identify Ceres-derived meteoritesin their geologic context.Visible and Infrared Mapping Spectrometer-----------------------------------------1. To provide a geologic, compositional and geophysical context forthe HED meteorites.2. To provide an opportunity to identify Ceres-derived meteorites intheir geologic context.3. To map the thermophysical properties of Vesta and Ceres.4. To determine the origin and evolution of Vesta and Ceres bymapping the mineralogical composition and its spatial variationacross the asteroidal surface.Gamma Ray and Neutron Detector------------------------------1. To map the major elemental composition of O, Si, Fe, Mg, Ti, Al,Ca, and H on Vesta and Ceres.2. To map the trace elements U, Th, K, Gd and Sm on Vesta and Ceres.3. To provide a geologic, compositional and geophysical context forthe HED meteorites.Gravity science---------------1. To determine the masses of the asteroids visited.2. To measure the bulk density of Vesta and Ceres, in conjunctionwith topography, and determine its heterogeneity.3. To determine the gravitational fields of Vesta and Ceres.The above science goals are extracted from the Dawn Science Plan(Raymond 2007).  Specific science measurement requirements necessaryto meet the stated science goals are outlined in the same document,as well as in Rayman et al. (2006).