Tags John Batchelor Dr. Marc Rayman Dr. David Livingston Dawn Mission Vesta Ceres ion propulsion reaction wheels Dawn mission launch Delta 2 Rocket Dawn scientific instrumentation Vesta relationship to Earth dwarf planets Vesta gravitational field Vesta soft landing Ceres bright spots Ceres salts Ceres flowing liquid Ceres astrobiology interest Ceres final orbit Guest John Batchelor Dr. David Livingston Dr. Marc Rayman Tagline Dawn Mission conclusion re Vesta and Ceres View the discussion thread.