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MicroMAPS is a gas filter correlation radiometer capable of detecting trace atmospheric gases by remotely sensing their infrared absorption characteristics. While the method can be used to detect a number of trace species (including CH4, SO2, and NO2), the current version of MicroMAPS detects CO and N2O from a nadir viewing orbital platform. To do this, the instrument is equipped with CO and N2O gas cells and configured to observe the earth's IR radiance in a band centered at 4.67 microns. It has been demonstrated that the synchronous detection of alternatively chopped signals through CO, vacuum and N2O view cells can produce a quantitative measure CO in three tropospheric layers. The simplicity of the method affords a low cost technique for generating global maps of this important atmospheric species when viewing from space. MicroMAPS uses the sam method of detection of trace CO as an older instrument called MAPS. MAPS (the measurement of air pollution from satellites) has heritage from shuttle missions in 1982, 1984, and 1994 (STS-2, STS-41G, and STS68). There are two fundamental differences between MicroMAPS and MAPS. To give the correlation signal related to the CO column density in the atmosphere, MicroMAPS employs a rotating gas cell chopper and a single IR detector. MAPS employs fixed gas cells with more than one detector. MicroMAPS replaces the complex amplifier and synchronous detector analog signal processing system of MAPS with a microprocessor based signal processor. The effect of these two changes reduces the weight from 100 lbs plus (MAPS) to approximately 14 lbs (MicroMAPS) as well as reducing the cost of MicroMAPS by about the same proportion as its mass. On June 8, 1994 CTA Incorporated of Rockport, Maryland was awarded a NASA contract to build the Clark spacecraft as part of the small satellite technology initiative program. In March 1995 Resonance Ltd. received a contract to build a spacequalified MicroMAPS remote sensor for this small satellite.
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