Data Set Overview : The LRO Camera consists of two Narrow Angle Cameras (NACs) that provide 0.5 meter-scale panchromatic images over a combined 5 km swath, a Wide Angle Camera (WAC) to provide images at a scale of 100 meters/pixel in seven color bands over a 60 km swath, (during the nominal 50 km primary mission phase) and a Sequence and Compressor System (SCS) supporting data acquisition for both cameras. LROC is a modified version of the Mars Reconnaissance Orbiters ConTeXt Camera (CTX) and MARs Color Imager (MARCI), built by Malin Space Science Systems (MSSS) in San Diego, CA.  The two NAC, WAC and SCS are located on the LRO Instrument bench, with NAC/WAC respective boresights aligned with the nadir (+Z) axis of the spacecraft. The SCS communicates with the LRO spacecraft over a high-speed SpaceWire interface, which provide both command and data communication pathways. LROC observations are stored on a solid state recorder (SSR) partition. Observations are downlinked to the ground using a Ka-band receiver, located at White Sands New Mexico, and processed by the MOC before being sent to the LROC Science Operations Center for processing into PDS EDR and CDR products.  Each NAC CCD, when it has completed an image integration, has the even and odd pixels read out through separate electronics, after which the data is companded from 12bit to 8bit, and finally losslessly compressed before being written to the spacecraft data recorder. On the ground processing by the LROC SOC uncompresses the data and then interleaves the pixels to produce the NAC EDR file. The label is populated with information obtained from the original image command, spacecraft housekeeping, and other computed values. No further processing is performed on the data at this stage.  The WAC CCD band passes are read out by the electronics, companded from 12bit to 8bit, and the losslessly compressed before being written to the spacecraft data recorder in real-time. For both monochrome and multi- spectral observations, frames (which consist of the VIS/UV bands commanded for the observation) are stored in a single band format. On the ground processing by the LROC SOC uncompresses the data to produce the WAC EDR file. The label is populated with information obtained from the original image command, spacecraft housekeeping, and other computed values. No further processing is performed.  This data release contains portions of the LROC Experiment Data Record (EDR) Archive, a collection of image data taken with the LROC instrument suite. A data release will contain both NAC and WAC EDR files from multiple days and multiple orbits.  This data release also contains ancillary data files: browse and thumbnail version of each observation; an index file ('index.tab') that tabulates the contents of this data release; a cumulative index file ('cumindex.tab') that tabulates the entire contents of the data set; and documentation files describing the data products, archive volume and calibration.  Processing : The LRO Mission Operations Center (MOC) pushes LROC science files (NAC and WAC observations), definitive SPICE kernels, LRO spacecraft and LROC instrument housekeeping and other ancillary files to the LROC SOC during the mission, on a daily basis. To process the NAC and WAC observations into PDS EDR products, the LROC SOC must ingest and process SPICE kernels and the housekeeping data to extract meta-data about each observation, including instrument temperatures and observation geometry on the lunar surface. Once the meta-data has been extracted and written into our database, the individual science files can then be processed into the respective EDR product.

Geometric Accuracy : Latitude and longitude coordinates calculated for the images given in the index.tab file were computed using the best available spacecraft position and orientation information at the time of processing, provide by the LRO Project in the form of SPK and CK kernel files. While these kernels should be equivalent to those retrievable from the NAIF web site (http://naif.jpl.nasa.gov), there may be small discrepancies and the NAIF versions of the kernels are preferred for all further processing.  Please refer to the white paper 'A Standardized Lunar Coordinate System for LRO' for details on LRO project adopted lunar coordinate system, which were used during the calculation of latitude and longitude coordinates.