This paper describes a Space Shuttle payload designed to measure infrared emissions from upper atmosphere airglow, aurora, and targets of opportunity in support of space defense operations. The payload, Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS-1A), consists of a Michelson interferometer for high-resolution spectral measurements and a dual-focal-plane radiometer with selectable band pass filters for spatial/clutter measurements in the 2.5-25-mu-m wavelength region. The interferometer and radiometer share the collection optics of a high off-axis-rejection telescope for simultaneous spectral and spatial measurements within the same field of view. The sensor optics and detectors are cooled to liquid helium temperatures to allow measurements of emissions from weak infrared sources in the 60-150 km upper atmosphere. CIRRIS-1A will be launched on STS-39 in early 1991 into a 57-deg inclination circular orbit at an altitude of 260 km.
