[Source: JAXA, http://www.eorc.jaxa.jp/JERS-1/en/index.html
JERS-1 is an Earth Observation Satellite to cover the global land area for national land survey, agriculture, forestry, and fishery, ... environmental protection, disaster protection, and coastal monitoring, etc. focusing on observation around the world and resource exploitation. It was launched into a solar-synchronous sub-recurrent orbit at an altitude of 568 km with a recurrent period of 44 days by the H-I launch vehicle on February 11, 1992 from National Space Development Agency of Japan (NASDA) Tanegashima Space Center, and has been continuing to observe and collect data with a mission data recorder by the high performance Synthetic Aperture Radar (SAR) and Optical Sensor (OPS).
SAR is an active sensor which transmits microwave and observes characteristics, inequality, slope in the surface of the earth, etc. without being influenced by the weather day and night due to scattered waves from the Earth.
OPS can observe in seven bands from the visible region to short wave infrared band and is capable of stereoscopic observation by forward look of 15.3 (J from nadir in near infrared band and highly is usable for identifying stones, rocks, and minerals.