The operational land imager: spectral response and spectral uniformity

The Landsat Data Continuity Mission (LDCM) will carry the Operational Land Imager (OLI) as one of its payloads. This instrument is a derivative of the Advanced Land Imager (ALI), flown on Earth Observing-1 (EO1) though it's mission is to continue the operational land imaging of the Landsat program. The OLI follows the highly successful Landsat-5 and Landsat-7 missions in continuing to populate an archive of earth images that dates back to 1972. The OLI has significant changes from the Landsat Thematic Mapper instruments, given that is the first pushbroom instrument in the program. However, it is intended to be a continuity mission, so the spatial coverage and spectral bands are similar. The suite of OLI's multispectral bands cover the same bandpasses but the panchromatic band is narrower than that of the ETM+. The OLI also has a shorter wavelength blue band for better resolution of coastal waters and a new band to aid in the detection of Cirrus clouds in the atmosphere. The thermal bands traditionally carried on the TM instruments have been moved to a separate instrument, also onboard the LDCM spacecraft. With the pushbroom design, each OLI multi-spectral band consists of nearly 7000 detectors. The OLI underwent prelaunch to verify a host of requirements on it's spectral performance, where was characterized at three different points during development. This paper will cover the results of the tests that attempt to validate the spectral uniformity requirements, including in-band response, out-of-band response, and spectral uniformity across the focal plane.