ASTER is a cooperative effort between NASA and Japan's Ministry of Economy Trade and Industry (METI), with the collaboration of scientific and industry organizations in both countries. The ASTER instrument provides the next generation in remote sensing imaging capabilities compared with the older Landsat Thematic Mapper, and Japan's JERS-1 OPS scanner. ASTER captures high spatial resolution data in 14 bands, from the visible to the thermal infrared wavelengths; and provides stereo viewing capability for digital elevation model creation. As the "zoom lens" for Terra, ASTER data are used by other Terra and space-borne instruments for validation and calibration.
Above is an illustration of the Terra spacecraft with the ASTER instrument highlighted. The links to the left under "Mission" will tell you about EOS, science applications, the instrument, and the ASTER airborne simulator.