Improved camera pointing and spacecraft ephemeris data for Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) images of the lunar poles.

NASA’s lunar exploration objectives, which include both robotic and human missions to the surface, require data products with high spatial resolution and accuracy. Using rigorous photogrammetric methods, we have co-aligned thousands of high-resolution images from the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) [Robbinson et al. 2010] of the lunar north and south pole. Both data sets are tied to Lunar Orbiter Laser Altimeter (LOLA) data [Smith et al. 2010a], which realizes the mean Earth/polar axis lunar reference frame [Archinal et al., 2018, Section 3]. The north pole data set includes improved orientation information for 9687 images acquired between September of 2009 and March of 2014 and has positional RMS residuals of 0.31 pixels (residuals are +/- 2.1 pixels at the 99th percentile). The south pole data set includes improved orientation information for 18,323 images acquired between July of 2009 and August of 2013, and has positional RMS residual of 0.48 pixels (residuals are +/- 1.3 pixels at the 99th percentile). Rather than release the updated images themselves, which are large, here we provide updated camera state and spacecraft ephemeris data in the form of NASA Navigation and Ancillary Information Facility (NAIF) Spacecraft, Planet, Instrument, C-matrix, Events (SPICE) kernels [Acton, 1996] These kernels can be applied to the LROC images included in our photogrammetric solutions to update the locations of images or used with any application that accepts SPICE kernels. This enables the creation of image mosaics under a range of illumination conditions, and the use of multi-image photoclinometry to derive topographic information. The kernels in this data release are organized by camera (LROC “left” – LE, and LROC “right” – RE), kernel type (*.bc camera kernels or SPICE CK, and *.bsp spacecraft kernels or SPICE SPK) and the time period (year) that the images were acquired. We also include summary files (*.doc) for each kernel that lists the images included in each kernel and the other SPICE kernels (e.g., PCK) applied to each image. Acton, C. H. (1996). Ancillary Data Services of NASA’s Navigation and Ancillary Information Facility. Planetary and Space Science, 44(1), pp. 65-70. Archinal, B. A., et al., 2018. Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015. Celestial Mechanics and Dynamical Astronomy, 130:22, https://doi.org/10.1007/s10569-017-9805-5. Robinson, M. S., et al., 2010. Lunar Reconnaissance Orbiter Camera (LROC) instrument overview. Space Sci. Rev. 150, 81 – 124, https://doi.org/10.1007/s11214-010-9634-2 Smith D. E., et al., 2010a. The Lunar Orbiter Laser Altimeter investigation on the Lunuar Reconnaissance Orbiter Mission. Space Sci. Rev. 150, 209-241, https://doi.org/10.1007/s11214-009-9512-y