INTERNATIONAL SPACE STATION AGRICULTURAL CAMERA (ISSAC) SENSOR ONBOARD THE INTERNATIONAL SPACE STATION (ISS) AND ITS POTENTIAL USE ON THE EARTH OBSERVATION

摘要

Recently launched and installed inside the Window Observational Research Facility (WORF) in the International Space Station (ISS), the International Space Station Agricultural Camera (ISSAC) sensor is an area-scan multi-spectral optical imaging system built by students and faculty at the University of North Dakota (UND). Radiometric calibration was conducted before launch and performance validation was evaluated with radiance extracted from Landsat5 TM image that was overpassed nearly at the same time as ISSAC overpass. Ground truth measurement with Analytical Spectral Devices (ASD, ASD Inc., Boulder CO) was also carried out over fairly homogenous regions of interest such as bare soil, gravel parking lot, crop and short grass pastures. Using the 6S radiative transfer model, radiances measured at the top-of-the atmosphere were converted into surface reflectance. Atmospheric corrected surface reflectance from ISSAC images was compared with the spectrum of ground ASD measurement. The results for both radiance and surface reflectance show fairly good agreements. This indicates that ISSAC would be a prospective candidate that would be able to fill the temporal gaps of Landsat 16-day revisit cycle. Higher rate of temporal opportunities from ISSAC sensor will result in significant improvement on decision making for users especially in time sensitive disaster management, farming practices or environmental issues occurred in short time frame.