Concepts for spaceborne hyperspectral imagery using prism spectrometers

Hughes Danbury Optical Systems (HDOS) has developed several concepts for hyperspectral remote sensing of the earth and major and minor planets. The basic instrument is an imaging prism spectrometer located on an orbiting platform. The spectrometer slit is imaged by a telescope on the planetary surface and pushbroom scanned across it. The prism spectrometer disperses the observed slit image and reimages it in the multiple spectral bands onto a 2D focal plane array. Extensive use is made of Application Specific Integrated Circuits (ASICs) for signal processing in order to reduce power and weight. The baselined focal plane array is a 320 (image) X 210 (spectral) InSb detector. This detector provides high quantum efficiency for photons spanning the spectral range from the band gap limit of 5.4 micrometers to the ultraviolet. Various spectral ranges and spectral resolutions may be selected by appropriate choice of the prism and design of the spectrometer optics. These concepts for a spaceborne imaging prism spectrometer rely heavily on HDOS's HYDICE heritage. HYDICE (HYperspectral Digital Imaging Collection Experiment) is a prism imaging spectrometer being developed by HDOS for the Naval Research Laboratory. HYDICE will fly in a Convair aircraft and pushbroom scan the earth in 210 spectral colors between 0.4 micrometers and 2.5 micrometers . The heritage for the miniaturized electronics in the HDOS Miniature Star Tracker program.