The first international space platform dedicated to Earth environmental research, developed and managed by the National Space Development Agency of Japan. Launched on 17 August 1996 aboard an H-II rocket from Tanegashima Space Center, it gathered data on climate change, the environment, and land and ocean processes. On 30 June 1997, ADEOS suffered damage to its solar array that made it go out of control and led to its subsequent failure.

There were eight instruments on board ADEOS, including the ocean colour and temperature scanner (OCTS), the interferometric monitor for greenhouse gases (IMGG), and the total ozone mapping spectrometer (TOMS). A second satellite, ADEOS-II, was launched on 14 December 2002. Its two main instruments were the advanced microwave scanning radiometer (AMSR; to observe the Earth's water cycle) and the global imager (GLI; for precise observations of the land, oceans, and clouds); last contact with the satellite was made in October 2003, when the satellite’s solar panels failed, ending the mission.