Dawn NASA’s Dawn Mission Journey to the Asteroid Frontier Lucy McFadden, Co-Investigator University of Maryland College Park, MD July 18, 2007 Night Sky Network 1

Dawn The Dawn Mission 9th mission in NASA’s Discovery Program 2

Dawn Traveling Back In Time 3

Dawn Dawn Explores the Earliest Epochs Vesta and Ceres are intact survivors of the earliest epoch of planetary formation. 4

Dawn The Asteroid Belt 5

Dawn Spacecraft Dry mass: 745 kg Wet mass: 1240 kg Solar array power (1 AU): 10.3 kW Solar array power (3 AU): 1.3 kW Delta II 7925H-9.5 6

Dawn Interplanetary Trajectory 7

Dawn Ion Propulsion Deep Space 1 8

Dawn Hydrazine tank 45 kg capacity Xenon tank 450 kg capacity Folded solar arrays Ion thruster 2.3 meters Ion Propulsion System 9

Dawn Instruments HGA – High Gain Antenna LGA – Low Gain Antenna CSS – Coarse Sun Sensors GRaND – Gamma Ray and Neutron Detector IPS Thrusters – Ion Propulsion Thrusters RCS Thrusters – Reaction Control System Thrusters VIR – Visual and Infrared Spectrometers FC – Framing Camera 10

Dawn Map the Gravity Field Vesta Gravity from Shape Model 11

Dawn Framing Camera FC current design (left) FC EM (below) Supports: Imaging Science Navigation Topography Gravity Science These functions are mission critical Two identical units to fly for 100% redundancy  1024 x 1024 pixels  frame-transfer CCD  14 µm pixel size  F/8 system  5.5° x 5.5° FoV  93 µrad iFoV (1 pixel)  7 filters + clear channel 12

Dawn Mapping Global Topographic Maps Framing Camera techniques have been proven on many previous missions. The camera’s most recent heritage comes from Venus Express. 13

Dawn Mapping Spectrometer: VIR VIR experiment is a compact imaging spectrometer housing two data channels in the same optical head. It is made of 2 modules Optical head Electronics box VIR will allow to perform spectroscopic measurements of the Vesta and Ceres surface in the range um were most signatures of rock-forming minerals are present 14

Dawn GRaND 25.7 cm 18.0 cm Cutaway view of GRaND Features  Neutron spectroscopy using Li-loaded glass and boron-loaded plastic phoswich  Gamma ray spectroscopy using Bismuth Germanate and Cadmium Zinc Telluride (new technology)  Design enables measurement and suppression of background from the space environment Operating modes  Standby  Operating  Anneal 15

Dawn Map the Elemental Composition Gamma ray and neutron detector (GRaND) techniques have been proven on Lunar Prospector. GRaND’s most recent heritage is from Mars Odyssey 16

Dawn Exploring New Worlds Dawn’s Itinerary: Launch September, 2007 The Dawn Spacecraft will travel 6.3 billion kilometers (almost 4 billion miles) In eight years To the asteroids, 4 Vesta and 1 Ceres. 17

Dawn Partners –University of California, Los Angeles Scientific Leadership –JPL – Jet Propulsion Laboratory Management and Navigation –Orbital Sciences Corporation Spacecraft design and build –Los Alamos National Laboratory GRAND instrument –DLR – German Aerospace Center Framing Camera –Max Planck Institute for Solar System Research Framing Camera –ASI – Italian Space Agency VIR –New Roads School, University of Maryland, and McREL Education and Public Outreach 18

Dawn Mission Timeline Launch Jun ‘07 (1) Ceres arrival Aug ‘15 (4) Vesta arrival Oct ‘11 (4) Vesta departure May ‘12 Mars gravity assist Mar ‘09 End of mission Jan ‘16 (1) Ceres arrival Sep ‘15 (4) Vesta departure Feb ‘12 Note: There is a continuum of options between the baseline and minimum, varying in scientific return, cost, and technical robustness. Baseline mission shown in green Minimum mission shown in blue 19

Dawn Background of Ceres First asteroid discovered in 1801 Biggest asteroid with a diameter about 1000 km a =2.77 AU, e =0.079, i =10.6  Probably hydrated (Lebofsky 1981, Feierberg 1981) or ammoniated (King et al. 1992) Target of Dawn, scheduled to orbit Ceres in 2015 for 11 months 20

Dawn 2007 Vesta apparition Vesta last made such a close approach to Earth in June,

Dawn Hubble Space Telescope 22

Dawn Vesta in May 2007 Wide Field Planetary Camera 2 (WFPC2) Four Filters: F439W, F673N, F953N, F1042M –Same filters as previous observations in 1994, Preliminary image deconvolution –Maximum Entropy Method (MEM) Color composite images: F439W+F673N 23

Dawn Hubble WFPC2 F439W image of asteroid Vesta in May 2007: raw 24

Dawn Hubble WFPC2 F439W Vesta in May 2007: deconvolved (MEM) 25

Dawn Hubble WFPC2 F439W images of asteroid Vesta in May 2007: raw 26

Dawn Hubble WFPC2 F439W Vesta in May 2007: deconvolved (MEM) 27

Dawn Hubble WFPC2 Vesta May 2007 Color Composite To watch the Rotation of Vesta, click here: 28

Dawn 500 km 29

Dawn Ceres observations Map Ceres through one complete rotation in multiple filters. Improve knowledge of its size, shape and pole orientation. Search for satellites Extend knowledge Apply to sequence planning for Dawn 30

Dawn Ceres 2003,

Dawn Hubble images of Ceres in January 2004 Advanced Camera for Surveys (ACS) High Resolution Channel (HRC) Filters: F220W, F330W, F555W Sub-sampled (dithered) images were drizzled to enhance resolution Color composite images: F330W+F555W Movies made from lower-resolution images (full phase coverage) 32

Dawn Hubble images of Ceres reveal roundness, surface features, and colors Three different faces of Ceres 33

Dawn Ceres ’ Rotation To see the video of Ceres’ rotation, go to: 34

Dawn 35

Dawn Learn More! 36

Dawn Unlocking the Mysteries Science on the Edge of Our Solar System 33 37