New geologic sketch maps and digital elevation models for King crater and the surrounding lunar farside highlands were created from Lunar Reconnaissance Orbiter Camera (LROC) Wide‐angle Camera (WAC) and Narrow Angle Camera (NAC) images. NAC images reveal that high volume impact melt accumulations exhibit evidence of dynamic processes during and following emplacement that resulted in downwarped zones, and other morphologic anomalies visible at the 50 cm pixel scale. Among the most significant of these forms are negative relief features, some of which may represent evidence for near‐surface caverns, offering points of access to subsurface environments and possible shelter from surface hazards. Other negative relief features may represent regions of extension and separation in response to possible subsurface drainage, together with isostatic readjustments, contraction, and/or compaction, in the cooling impact melt. Crater counts on the continuous ejecta blanket suggest a Late Eratosthenian to Copernican age for King crater, which is older than the estimate of Young (1977), but consistent with those of others.
One of the primary objectives of the Lunar Reconnaissance Orbiter Camera (LROC) is to acquire stereo observations with the Narrow Angle Camera (NAC) to enable production of high resolution digital elevation models (DEMs). This work describes the processes and techniques used in reducing the NAC stereo observations to DEMs through a combination of USGS integrated Software for Imagers and Spectrometers (ISIS) and SOCET SET from BAE Systems by a team at Arizona State University (ASU). LROC Science Operations Center personnel have thus far reduced 130 stereo observations to DEMs of more than 130 stereo pairs for 11 Constellation Program (CxP) sites and 53 other regions of scientific interest. The NAC DEM spatial sampling is typically 2 meters, and the vertical precision is 1-2 meters. Such high resolution provides the three-dimensional view of the lunar surface required for site selection, hazard avoidance and planning traverses that minimize resource consumption. In addition to exploration analysis, geologists can measure parameters such as elevation, slope, and volume to place constraints on composition and geologic history. The NAC DEMs are released and archived through NASA's Planetary Data System.
ABSTRACT:The Lunar Reconnaissance Orbiter Camera (LROC) consists of three imaging systems: a Wide Angle Camera (WAC) and two Narrow Angle Cameras (NACs). Since entering lunar orbit in June of 2009, LROC has collected over 700,000 images. A subset of WAC images were reduced into a global morphologic basemap, a near-global digital elevation model, and multitemporal movie sequences that characterize illumination conditions of the polar regions. In addition, NAC observations were reduced to meter scale maps and digital elevation models of select regions of interest. These Reduced Data Record (RDR) products were publicly released through NASA's Planetary Data System to aid scientists and engineers in planning future lunar missions and addressing key science questions. INSTRUMENT OVERVIEWThe Lunar Reconnaissance Orbiter Camera (LROC) system provides synoptic and high resolution imaging of the lunar surface . The Wide Angle Camera (WAC) is a seven band (315, 360, 415, 566, 604, 643, 689nm) push frame imager with a 90° field of view in monochrome mode, and 60° field of view in multispectral mode. From the nominal 50 km polar orbit, the WAC acquires images with a nadir pixel scale of 75 meters for the visible filters (384 meters for the UV filters). The WAC images almost the entire Moon each month, capturing the lunar surface under a variety of lighting conditions over time. This global dataset enables the creation of morphologic maps, near-global digital elevation models (DEMs), and polar illumination movie sequences.The Narrow Angle Camera (NAC) consists of two line scan cameras that provide high resolution images at a pixel scale of 0.5 to 2.0 meters and a combined field of view of 5.7°. Around summer solstice at each lunar pole, when shadows are at a minimum, hundreds of images are acquired and later reduced into high resolution maps. These NAC polar mosaics extend from the pole out to 85.5° N/S and have a pixel scale of two meters. In addition to polar mosaics, high resolution (pixel scale between 0.5 and 2.0 meters) maps are also created for other regions of interest across the Moon. Finally, NAC stereo observations are also processed into high resolution DEMs. DEMs generated from NAC stereo pairs acquired over many months are processed and mosaicked to create regional terrain models with a pixel scale of two to five meters.Since entering orbit in 2009, LROC has acquired over 700,000 images WAC and NAC images. A subset of this image collection provides the basis for the production of DEMs and image mosaics over a broad range of spatial scales. LROC images (Experiment Data Records, or EDR) and Reduced Data Record (RDR) products created by the LROC team are publicly released through NASA's Planetary Data System to aid scientists and engineers investigating the Moon [Jolliff et al., 2011, Mahanti et al., 2012 Ashley et al., 2012]. REDUCED DATA RECORDS WAC Global BasemapThe WAC global mosaic is comprised of over 15,000 images acquired between November 2009 and February 2011. The WAC maps the whole Moon in one month, ...
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