Orbital SORCE - Manual (Page 2)

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SORCE
Key Mission Partners
University of Colorado at Boulder,
Laboratory for Atmospheric and
Space Physics
Principal Investigator: Dr. Gary J.
Rottman, Associate Director LASP/
CU; Space and ground segment
management, instrument development,
ground data system, mission operations
and science team management
NASA Goddard
Space Flight Center
Project management and science data
archives
Orbital Sciences Corporation
Spacecraft bus development, satellite
integration and test, launch vehicle
integration, flight operations support and
Pegasus launch vehicle
Science Team
Co-Investigators
• Laboratory for Atmospheric and Space
Physics (LASP) University of Colorado
• Astrophysical and Planetary Sciences
(APS) University of Colorado
• Naval Research Laboratory (NRL)
• High Altitude Observatory/National
Center for Atmospheric Research
(HAO/NCAR)
• NASA Ames Research Center
Specifications
Spacecraft
Satellite Mass: 290 kg (639 lb.)
Redundancy: Near fully redundant
Solar Arrays: Fixed GaAs
Power: 348 W
Stabilization: 3-axis, zero momentum; Capability: Slew rate >1 ° /sec;
Knowledge: <36 arcsec; Control: <60 arcsec
Communications: Redundant S-band transceivers
Mission Life:
5 years; 6-year goal
Orbit: 645 km, 40° inclination
Status: Baseline mission complete, currently in extended mission operations
Launch
Launch Vehicle: Pegasus ® XL
Site: KSC, Cape Canaveral, Florida
Date: January 25, 2003
Instruments
Total Irradiance Monitor (TIM)
Measures the total solar irradiance (TSI) at 100 parts per million accuracy for the duration of the
SORCE mission by monitoring changes in incident sunlight to the Earth’s atmosphere via an ambient
temperature active cavity radiometer.
Spectral Irradiance Monitor (SIM)
Measures the solar spectral irradiance in the 200 to 2,000 nanometer range and contains two
completely independent and identical (mirror-image) spectrometers, which are fully interchangeable.
Solar Stellar Comparison Experiment (SOLSTICE)
Provides precise daily measurements of solar spectral irradiance at ultraviolet wavelengths.
Measurements provide coverage from 115 nanometer to 300 nanometer with a spectral resolution
between 0.1-0.2 nanometer, an absolute accuracy better than 5 percent, and a relative accuracy of
0.5 percent.
Extreme Ultraviolet Photometer System (XPS)
Measures the solar irradiance and consists of a package of twelve silicon XUV photodiodes for
measuring the XUV and EUV irradiance from 1 to 35 nanometers.
Space Segment
The SORCE space segment consists of the LASP-supplied Instrument
Module and the Orbital-supplied spacecraft bus combined to form the
SORCE satellite. The spacecraft bus provides all the on-orbit support
required for the instrument suite to obtain the mission science data and
transmit it to the ground for distribution and processing. SORCE measures
the Sun’s output with the use of state-of-the-art radiometers, spectrometers,
photodiodes, detectors, and bolometers engineered into the suite of
instruments.
Ground Segment
The ground segment is comprised of the Mission Operations Center (MOC),
the Science Operations Center (SOC), and the ground antenna site. The
MOC, located at LASP’s facility in Boulder, Colorado, is responsible for
command and control of the satellite and mission science planning. NASA’s
Space/Ground Network, through antenna sites at Wallops Island, Virginia,
provides the communication link to the satellite. LASP provides the SOC
for science data processing and distribution to the NASA-GSFC Distributed
Active Archive Center (DAAC).