MOS-1 (Marine Observation Satellite) "Momo-1" is the Japan's first Earth Observation Satellite developed applying domestic technologies as a part of Satellite Earth Observation Systems for contributing to effective utilization of Earth resources, environmental protection, etc.

MOS-series satellites orbit the Earth at an altitude of 909 km in 103 minutes always facing their observation equipment to the Earth. Each of them carries three sensors, Multispectral Electronic Self-Scanning Radiometer (MESSR), Visible and Thermal Infrared Radiometer (VTIR), and Microwave Scanning Radiometer (MSR), their observation data are acquired by overseas ground stations as well as our domestic data acquisition stations and utilized extensively.