Title of Presentation: The Spaceborne Infrared Atmospheric Sounder for Geosynchronous Earth Orbit (SIRAS-G ) – Pathfinder IR Imaging Spectrometer for Space Missions

Primary (Corresponding) Author: Thomas U. Kampe

Organization of Primary Author: Ball Aerospace & Technologies Corp.

Co-Authors: Holden Chase, Vincent Kotsubo, Paul Hendershott, Gary Mills, John Wassmer


Abstract:  The Spaceborne Infrared Sounder for Geosynchronous Earth Orbit (SIRAS-G), developed by Ball Aerospace & Technologies Corp (BATC), was developed under NASA’s 2002 Instrument Incubator Program (IIP-4). SIRAS-G provides a compact, low mass solution for imaging IR spectrometers exhibiting low spectral smile and keystone distortion suitable for future Earth science needs.  SIRAS-G technology is ideally suited for measuring atmospheric temperature, water vapor, trace gases and dust aerosol from satellite, providing high-spectral resolution imaging spectroscopy over a broad IR spectral range and extended field of view. Instrument concepts are presented for future mission in LEO and GEO. One such instrument concept flown in LEO has the potential to provide improved spatial resolution, comparable to that of MODIS that would improving the yield of cloud-free pixels and tracking of the transport trace gases. The SIRAS-G dispersive spectrometer module is readily adaptable for missions in LEO, GEO and MEO orbits and can be optimized for spectral resolution over subsets of the total spectral range. We have completed the 3-year SIRAS-G IIP development effort, including successful testing of the demonstration instrument at cryogenic temperatures. The performance of the demo instrument has been quantified including measurement of keystone distortion, spectral smile, MTF, and the spectral response function (SRF) to high accuracy using novel test methodologies developed at BATC. We present the results of the laboratory instrument development including results of our characterization of the demonstration instrument. We discuss instrument concepts utilizing SIRAS-G technology for potential future missions including an anticipated airborne flight demonstration.

Key Words: imaging spectrometry, infrared sounding, remote sensing, geosynchronous remote sensing, atmospheric sounding, atmospheric trace gases