Plans are underway at NASA/Goddard Space Flight Center to develop a moderate resolution (0.5-1.0 kilometer) imaging spectrometer with 104 spectral bands in the range from 0.4 to 14.2 micrometers for use as a NASA facility aboard the Earth Observing System (EOS). Science requirements call for the system to image the Earth's surface every 2 days for a period in excess of 10 years. Numerous and diverse tasks in the areas of terrestrial, oceanic, and atmospheric science require two electro-optical sensors. MODIS-T (tilt) is a sixty-four channel imaging spectrometer with 10-nanometer wide channels in the 0.4-1.0 micrometers spectral range. The system has 5 centimeter diameter optics, scans ±45°, and can be pointed in the range ±60° along track. Calculated S/N is in excess of 800:1 near 0.4 micrometers. MODIS-N (nadir) is a 40-channel imaging spectroradiometer that scans ±45° about nadir with twelve 500 meter and twenty-eight 1000 meter resolu-tion channels including two polarization channels and fourteen thermal infrared channels. With 20 centimeter diameter optics, the calculated S/N's of the majority of the reflected solar bands are over 1000:1. NETD for the thermal bands are on the order of 0.1-0.2 K at 300 K. Combined MODIS-T and MODIS-N data rates are 8.3 megabits per second in daylight, 1.5 megabits per second at night resulting in a total of 3.6 x 1011 bits per day.
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