Within ten years from now, large polar platforms intended to be built by the United States, Europe and Japan are expected to enter into operational service. These platforms will offer significant improvements over the capabilities of current earth observation satellites in terms of mass, power and data rate available to the payload. New instruments must therefore be developed to optimally exploit these capabilities, taking advantage of the last developments in optical systems, data processing and detector technology. The paper describes two such instruments primarily designed for land applications in the frame of the European earth observation preparatory program : a thermal infrared push-broom imager ('[IRI) and a high resolution imaging spectrometer (HRIS). As its name indicates, TIRI is an optical imager specifically designed to work in the 8-12 micron band, split in two spectral channels. Each line of the image being electronically scanned by linear arrays of detectors, no mechanical scanning device is required. Ground resolution is 30 m, with 0.1°K NE T. HRIS is required to provide very high resolution, both spatially (30 m) and spectrally (5 nm in VN1R, 10 nm in SWIR) ; in total, there are 260 spectral channels among which any set of 30 individual channels can be selected for transmission to ground ; low spectral resolution modes are also possible by combining several channels. TIRI and HRIS are large instruments each weighting about 350 kg. Both have a relatively narrow swath width of 30 km, combined with an off-track pointing capability over + 30° from nadir.