During 1989-1991 studies were undertaken for the design of a dedicated German satellite, Atmos, which would have
concentrated investigations on the Earth's atmosphere. From a 775-km, sun-synchronous orbit, Atmos was to have been
launched in the mid-1990's with four major Earth observation systems: the Advanced Millimeter Wave Atmospheric Sounder
(AMAS), the Michelson Interferometer for Passive Sounding (MIPAS), the Scanning Imaging Absorption Spectrometer for
Atmospheric Cartography (SCIAMACHY), and the Reflective Optics Imaging Spectrometer (ROSIS). The first three devices
were designed to analyze atmospheric chemistry, whereas the objective of ROSIS was to return moderate and high resolution,
multispectral photographs of the Earth's surface (Reference 558). The Atmos program has been reoriented to provide some or
all of the abovementioned instruments to ESA's Envisat satellite.