Orbital Dawn - Manual (Page 2)

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Dawn
Key Mission Partners
UCLA, Jet Propulsion Laboratory
Principal Investigator: Dr. Christopher Russell; project
management, system engineering, ion propulsion
subsystem, science operations and spacecraft flight
operations
Orbital Sciences Corporation
Spacecraft design, integration and test, flight software,
and launch operations
Max Planck Institute for Solar System Research/
German space agency (MPS/DLR)
Katlenburg-Lindau, Germany
Italian space agency/National Institute for Astro-
physics (ASI/INAF)
Rome, Italy
Kennedy Space Center
Launch services via NASA Launch Services Contract
Dawn Mission "Firsts"
• The Dawn spacecraft is the first to orbit two planetary
bodies during a single mission.
• Dawn is the first mission to study two of the largest
asteroids in the main belt.
• Dawn is NASA's first purely scientific mission to be
powered by ion propulsion.
• Dawn is Orbital’s first planetary mission. The spacecraft
design draws on the company’s extensive flight-proven
heritage.
Specifications
Spacecraft
Mass: 1,210 kg (2,668 lb.) at launch, 740 kg (1,631 lb.) dry
Dimensions: 20 m (65 ft) tip-to-tip, spacecraft body is 2 m (6 ft)
high from separation plane to instrument deck
Power: Gallium Arsenide triple junction solar arrays, 10 kW
at Earth and 1.4 kW at Ceres
Communications: Deep Space Network – compatible with science
downlink rates of 41-128 kbps
Propulsion: Solar-electric propulsion using three gimbaled
NSTAR ion engines and monopropellant reaction
control system
Orbit Altitude: At target asteroids: As high as 4,500 km and as low
as 25 km
Mission Life: 10 years
Reliability: Redundant and cross-strapped spacecraft bus
electronics
Heritage: GALEX, SORCE, Deep Space 1, STAR ™ Bus
Status: Fully operational
Launch
Launch Vehicle: Delta II 7925H
Site: Kennedy Space Center
Date: September 27, 2007
Instruments
Two Framing Cameras (MPS/DLR)
Visible and Infrared Mapping Spectrometer (ASI/INAF)
Gamma Ray and Neutron Detector (LANL)
Diagram of Dawn Spacecraft
Solar Array
High Gain
Antenna
RCS
Thrusters
IPS
Thrusters
Radiator Panel
with Louvers
Gamma Ray/Neutron
Spectrometer
Low Gain
Antenna
Star
Trackers
Framing
Cameras
VIR
Low Gain
Antenna
Y
Z
X