In the field of the scientific cooperation between our two Institutes started in 1986, a common research program was developed for the analysis of the characteristics and the application of advanced spaceborne optical sensors for the remote sensing of the Earth. This program has become a part of the international scientific project PRIRODA. The space module PRIRODA is the technical base for the project. It was launched, and attached to the inhabited space platform MIR in April 1996. By means of the optical sensors placed on board of the PRIRODA module, we are going to study the geophysical parameters useful for environmental monitoring and resources evaluation. The principal attention is paid to the study of the following topics: (1) water quality in the coastal zone and particularly near the river estuaries; (2) vegetation stress due to the anthropogenic activities; (3) geophysical studies in areas of geothermal and volcanic activities; (4) estimation and verification of the atmosphere contributions. In order to perform the goals mentioned above, the Italian side has identified some test sites mainly in the Tuscany region and the data from the following optical sensors of the PRIRODA module, will be utilized: (1) ISTOK-1, the instrument is a 64-channel infrared spectro-radiometer in the band of 4 - 16 micrometer to measure both the atmospheric transmittance spectrum by looking at the Sun and the thermal emission spectrum of the atmosphere and the Earth surface under different angles of pointing. In addition the instrument includes a TV CCD camera to observe the clouds and the Earth surface (2) MOS-OBSOR, this imaging spectrometer is dedicated to the investigation of the reflected solar radiation in the atmosphere -- Earth surface system in the visible and near infrared ranges. The apparatus consists of different optical blocks and is comprehensive of on-board data compression. (3) MOMS-2P, this modular optoelectronic multispectral stereo scanner consists of two subunits: a threefold stereoscopic imaging system and a four-band multispectral camera with nadir orientation. The instrument parameters were designed in order to fill the gap between existing spaceborne system and airborne photography. (4)MSU-E, this electro-optical scanner is mainly devoted to investigate the reflected solar radiation in the 'atmosphere -- Earth surface' system at a spatial resolution of 25 m in three visible and near infrared spectral bands. (5) MSU-SK, this opto-mechanical scanner operates in four adjacent visible and near infrared bands at 120 m of spatial resolution plus one band in the thermal infrared region with 300 m of spatial resolution. An additional feature consists of the possibility to tilt the field of view of the scanner up to 30 degrees in the plane normal to the flight direction. Preliminary results, coming from the data collected by these sensors, are presented, discussed and compared with the data collected by field experiments on the test areas overflight by the MIR.