CubeSat Infrared Atmospheric Sounder (CIRAS)

The CubeSat Infrared Atmospheric Sounder (CIRAS) will measure upwelling infrared radiation of the Earth in the MWIR region of the spectrum from space on a CubeSat. The observed radiances can be assimilated into weather forecast models and be used to retrieve lower tropospheric temperature and water vapor for climate studies. Multiple units can be flown to improve temporal coverage or apply different spectral ranges to look at other atmospheric trace gases in the infrared including CO, CO2, CH4, O3, and SO2. Higher spatial resolution units can be developed with the same optics and detector array, with a lower detector operating temperature and consequently more power from the spacecraft. Higher spatial resolution and formation flying can provide new data products including 3D motion vector winds. CIRAS incorporates three new instrument technologies. The first is a 2D array of High Operating Temperature Barrier Infrared Detector (HOT-BIRD) material, selected for its high uniformity, low cost, low noise and higher operating temperatures than traditional materials. The detectors are hybridized to a commercial ROIC and commercial camera electronics and dewar package. The second technology is a Lockheed Martin Coaxial Micro Pulse Tube (MPT) cryocooler. The MPT offers high cooling capacity in a CubeSat compatible package and its flexure bearing technology enables significantly longer mission life. The third technology is an MWIR Grating Spectrometer (MGS) designed to provide imaging spectroscopy for atmospheric sounding in a CubeSat volume. The MGS has no moving parts and is based on heritage spectrometers including the (OCO-2) and the JPL/Ball Spaceborne Infrared Atmospheric Sounder (SIRAS) IIP. JPL will also develop the mechanical, electronic and thermal subsystems for CIRAS, with satellite components procured from Blue Canyon Technologies. The integrated system will be a complete 6U CubeSat capable of measuring temperature and water vapor profiles with good lower tropospheric sensitivity. The CIRAS is the first step towards the development of an Earth Observation Nanosatellite Infrared (EON-IR) capable of meeting the replacement needs of the CrIS, including both the MWIR and LWIR regions of the spectrum.