EWS Rapid Revisit Optical Cloud Imager Testing & Calibration

The U.S. Space Force is evaluating technologies for a new Electro-Optical/Infrared (EO/IR) weather system (EWS) constellation to provide global cloud characterization and theater weather imagery to Department of Defense Weather Centrals. The Rapid Revisit Optical Cloud Imager (RROCI) satellite built by Orion Space Solutions is a CubeSat technology demonstration mission designed to collect weather imagery in 8 visible and infrared spectral bands. Accurate cloud products require that both the spectral radiance values and the geolocation of each image pixel be accurately determined. The instrumentation payload consists of nadir Vis, SWIR, MWIR, and LWIR cameras with filters set to the target wavelengths. Comprehensive instrument-level testing and radiometric calibrations were performed at the Utah State University Space Dynamics Laboratory (SDL) prior to launch. The instrument-level radiometric accuracy, noise, and relative spectral response for each spectral band are consistent with model predictions. Critical to the performance of the instrument are the longwave-infrared bands, which require the microbolometer detectors to maintain radiometric stability over the 100-minute on-orbit calibration period. Using MODIS radiances as simulated data along with noise derived from the radiometric calibration shows that the payload can achieve the EWS weather objectives.