Marine Observation Satellite

Japanese earth sea satellite. The MOS 1A and 1B satellites, also known as Momo 1A and 1B, were Japan's first Earth resources satellites.

The satellites were designed to monitor ocean currents, sea surface temperature, atmospheric water vapor, ocean chlorophyll levels, precipitation, and land vegetation. They also acted as relays for data from remote surface sensor platforms.

MOS 1B was upgraded for flight from the engineering model for MOS 1A. The spacecraft was nadir pointing, 3-axis stabilized with momentum wheels and hydrazine thrusters. Communications consisted of S-, X-band downlink, and S-band uplink. A single solar panel with 1-axis articulation provided power. The payload included:

• Multispectral Electronic Self-Scanning Radiometer (MESSR) - covers 4 bands between 0.51 and 1.1 micron, 50 m resolution, 200 km swath. Designed to observe ice distribution, land use, snow cover, ocean chlorophyll.
• Visible and Thermal Infrared Radiometer (VTIR) - covers 6 bands between 0.5 and 12.5 microns, 0.9 - 2.7 km resolution, 1500 km swath. Designed to monitor snow, cloud, ice coverage, sea surface temperatures.
• Microwave Scanning Radiometer (MSR) - 2 frequency radiometer (23.8, 31.4 GHz) with 23-32 km resolution, 317 km swath. Monitored atmospheric water vapor content, snowfall, and rainfall.