Lawrence Livermore National Laboratory developed a space-qualified High Resolution (HiRes) imaging LIDAR (LIght Detection And Ranging) system for use on the DoD Clementine mission. The Clementine mission provided more than 1.7 million images of the moon, earth, and stars, including the first ever complete systematic surface mapping of the moon from the ultraviolet to near-infrared spectral regions. This article describes the Clementine HiResLIDAR system, discusses design goals and preliminary estimates of on-orbit performance, and summarizes lessons learned in building and using the sensor. The LIDAR receiver system consists of a High Resolution (HiRes) imaging channel which incorporates an intensified multi-spectral visible camera combined with a Laser ranging channel which uses an avalanche photo-diode for laser pulse detection and timing. The receiver was bore sighted to a lightweight McDonnell-Douglas diode-pumped NdYAG laser transmitter that emmitted 1.06 pm wavelength pulses of 200 mJ/pulse and 10 ns pulse-width. The LIDAR receiver uses a common F/9.5 Cassegrain telescope assembly. The optical path of the telescope is split using a color-separating beamsplitter. The imaging channel incorporates a filter wheel assembly which spectrally selects the light which is imaged onto a custom 12 mm gated image intensifier fiber-optically-coupled into a 384 x 276 pixel frame transfer CCD FPA. The image intensifier was spectrally sensitive over the 0.4 to 0.8 pm wavelength region. The six-position filter wheel contained 4 narrow spectral filters, one broadband and one blocking filter. At periselene (400 km) the HiResLIDAR imaged a 2.8 km swath width at 20meter resolution. The LIDAR function detected differential signal return with a 40-meter range accuracy, with a maximum range capability of 640 km, limited by the bit counter in the range return counting clock. The Imagery from the HiRes is most useful for smaller scale topography studies, while the LIDAR data is used for global terrain and inferred gravity maps.
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