MOS 1A, 1B
Marine Observation 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.

Spacecraft
3-axis stabilized with momentum wheels, hydrazine thrusters. Nadir pointing. S-, X-band downlink, S-band uplink. Single solar panel with 1-axis articulation.

Payload
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, snowcover, 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. Montiors atmospheric water vapor content, snowfall, and rainfall.

Country of Origin	Japan
Customer/User	NASDA
Manufacturer(s)	NEC
Size	1.3 x 2.4 x 1.5 m (bus), 5.3 x 2 m solar panel
Orbit	909 km circular, sun-synchronous, 99 deg inclination, with 17 day repeat period and 10 am descending node
Design Life	2 years
Related Sites	NASDA MOS Page

Launch Facts

Name	Int'l Desig.	Date	Site	Vehicle	Orbit	Mass(kg)
Notes
MOS 1A (MOMO 1)	1987-018A	2/18/87	Tanegashima	N-2	LEO	745
Ocean remote sensing
MOS 1B (MOMO 1B)	1990-013A	2/7/90	Tanegashima	H-1	LEO	740
Marine observation