The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key instrument on the Earth Observing System (EOS)-AM1 spacecraft, scheduled for launch in 1998. MODIS, developed by Raytheon Santa Barbara Remote Sensing (SBRS), consists of 36 spectral bands with geometric instantaneous-fields-of-view (GIFOV’s) of 0.25-, 0.5-, and 1.0-km at nadir. The system has completed extensive testing, demonstrating compliance with NASA's demanding requirements. The MODIS Science Team, an international group of 28 scientists, has begun delivering algorithms to calculate 42 standard data products, including atmospheric aerosols, snow cover, land and water surface temperature, leaf area index, ocean chlorophyll concentration, and sea ice extent. The system-level testing included measurements in ambient and thermal-vacuum environments to ensure specification compliance and enable post-launch radiometric calibration. The tests verified the performance of onboard calibration systems, such as the solar diffuser stability monitor (SDSM), blackbody (BB), and spectral radiometric calibration assembly (SRCA). MODIS's design choices, such as the use of a cross-track scanner and a double-sided, continuous rotation, paddle wheel scan mirror, were driven by the need to balance sensitivity, optics size, band-to-band registration, and scan rates. The instrument's physical and performance characteristics, including size, mass, power, data rate, spatial, spectral, radiometric, and stray light response, have been characterized. The results show that MODIS meets or exceeds most of NASA's requirements, with some bands exceeding the specified sensitivity and dynamic range. The MODIS has been integrated onto the EOS-AM1 spacecraft, and extensive system-level tests are ongoing. The launch is scheduled for 1998.The Moderate Resolution Imaging Spectroradiometer (MODIS) is a key instrument on the Earth Observing System (EOS)-AM1 spacecraft, scheduled for launch in 1998. MODIS, developed by Raytheon Santa Barbara Remote Sensing (SBRS), consists of 36 spectral bands with geometric instantaneous-fields-of-view (GIFOV’s) of 0.25-, 0.5-, and 1.0-km at nadir. The system has completed extensive testing, demonstrating compliance with NASA's demanding requirements. The MODIS Science Team, an international group of 28 scientists, has begun delivering algorithms to calculate 42 standard data products, including atmospheric aerosols, snow cover, land and water surface temperature, leaf area index, ocean chlorophyll concentration, and sea ice extent. The system-level testing included measurements in ambient and thermal-vacuum environments to ensure specification compliance and enable post-launch radiometric calibration. The tests verified the performance of onboard calibration systems, such as the solar diffuser stability monitor (SDSM), blackbody (BB), and spectral radiometric calibration assembly (SRCA). MODIS's design choices, such as the use of a cross-track scanner and a double-sided, continuous rotation, paddle wheel scan mirror, were driven by the need to balance sensitivity, optics size, band-to-band registration, and scan rates. The instrument's physical and performance characteristics, including size, mass, power, data rate, spatial, spectral, radiometric, and stray light response, have been characterized. The results show that MODIS meets or exceeds most of NASA's requirements, with some bands exceeding the specified sensitivity and dynamic range. The MODIS has been integrated onto the EOS-AM1 spacecraft, and extensive system-level tests are ongoing. The launch is scheduled for 1998.