Radiometric calibration with the Moon (called the lunar calibration) is a promising method for evaluating the performance of instruments onboard satellites. In particular, the lunar calibration can provide inflight radiometric calibration opportunities for nano/microsatellites after the launch without any special equipment. In this study, we have conducted more than one year of Moon observations with a microsatellite named RISESAT. The performance of an onboard multispectral sensor OOC is investigated by using the ROLO and SELENE/SP Moon models. Our lunar calibration revealed the dependence of the sensor sensitivity on the instrument temperature, and no sensitivity degradation (< 1 %) can be confirmed for all four channels after the correction of the temperature dependence. Lunar calibration also revealed the bluing trend in the OOC’ s inter-band ratio, which indicates a 15% alternation in the sensitivity at maximum. This bluing trend was validated by the Railroad Valley Playa observations as comparing the Landsat-8/OLI data.