The objectives of the ADEOS (Advanced Earth Observing Satellite) mission are to acquire data on worldwide environmental changes such as the green house effect, ozone layer depletion, tropical rain forest deforestation, and abnormal climatic conditions, in order to contribue to international global environmental monitoring and to develop platform bus technology, interorbital data relay technology, etc. which are necessary for the development of future Earth observation systems.

To make continuous, thorough observations of the entire earth survace and its atmosphere, the spacecraft carries two core sensors develped by the National Space Development Agency (NASDA) of Japan: the advanced Visible and Near Infrared Radiometer (AVNIR) and the Ocean Color and Temperature Sensor (OCTS). In addition, the spacecraft carries six Announcement of Opportunity (AO) sensors: the NASA Scatterometer (NSCAT) and Total Ozone Mapping Spectrometer (TOMS), Polarization and Directionality of the Earth's Reflectance (POLDER) provided by CNES, the Interferometric Monitor for Greenhouse Gases (IMG) provided by the Ministry of International Trade and Industries, and the Improved Limb Atmospheric Spectrometer (ILAS) and Retroreflector in Space (RIS) provide by Environment Agency of Japan.

The RIS is a retroreflector for an Earth-to-satellite-to-Earth laser used in long-path absorption experiments. RIS has a corner-cube structure with an effective diameter of 50 cm. Measurements of ozone, CFC12, CO2, CH4, etc. are carried out using infrared pulsed lasers.

ADEOS/RIS Characteristics: