An Introduction to the Department of Energy's Multispectral Thermal Imager (MTI) Project Emphasizing the Imaging and Calibration Subsystems

MTI is a comprehensive research and development project that includes up-front modeling and analysis, system design, fabrication, assembly and testing, on-orbit operations, and experimentation and data analysis. The satellite is designed to collect radiometrically calibrated, medium resolution imagery in 15 spectral bands ranging from 0.45 to 10.70 μm. The combination of spectral bands, very accurate radiometry and good spatial resolution make MTI unique among current and planned space-based imaging systems. The imaging system includes a three-mirror anastigmatic off-axis telescope, a single cryogenically cooled focal plane assembly, a mechanical cooler, and an onboard calibration system. The single focal plane sensor design alleviates the need for a beam splitter to separate spectral components, and it permits cold operation for ground test and alignment, while the telescope and electronics are at laboratory ambient temperature and pressure. Payload electronic subsystems include image digitizers, real-time image compressors and a solid state recorder. All payload components have been fabricated and tested, and the payload is integrated and currently undergoing environmental testing in preparation for calibration.