Status of the atmospheric infrared sounder (AIRS)

The Atmospheric Infrared Sounder (AIRS) is being developed for the NASA Earth Observing System (EOS) program with a scheduled launch on the first post meridian (PM1) platform in the year 2000. AIRS is designed to provide both new and more accurate data about the atmosphere, land, and oceans for application to climate studies and weather prediction. Among the important parameters to be derived from AIRS observations are atmospheric temperature profiles with an average accuracy of 1 K in 1 kilometer (km) layers in the troposphere and surface temperatures with an average accuracy of 0.5 K. The AIRS measurement technique is based on very sensitive passive infrared (IR) remote sensing using a precisely calibrated, high resolution grating spectrometer operating in the 3.7 mu m to 15.4 mu m region. The instrument concept uses passively cooled multi-aperture eschelle array spectrometer approach in combination with advanced state-of-the-art focal plane and cryogenic refrigerator technology to achieve unparalleled performance capability in a practical long life configuration. AIRS is a key component of NASA's Global Change Research Program, and is expected to play an important role in the converged National Polar Orbiting Environmental Satellite System (NPOESS), now under study. This paper provides a brief description of the AIRS Instrument design and focuses on the current development status of hardware currently being fabricated for the engineering model. In particular, the paper will address the status and expected performance of the AIRS focal plane assembly, the cryocooler, and components of the optical spectrometer.