PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH OBJECT = TEXT PUBLICATION_DATE = 2007-06-21 INTERCHANGE_FORMAT = ASCII NOTE = "N/A" END_OBJECT = TEXT END PLEASE NOTE: This archive has been migrated from PDS3 to PDS4. The contents and directory structure of the PDS3 archive have not changed, but PDS4 metadata in the form of XML files have been added. The file README_CLEMENTINE1_LIDAR.TXT in the root directory has more information. The file you are now reading, AAREADME.TXT, was written for the original PDS3 archive and does not have information about the PDS4 additions. ---- Original contents of AAREADME.TXT are below this line. ---- Clementine Lunar LIDAR (Laser Image Detection and Ranging) Data 1. Introduction This archive contains LIDAR data from the Clementine Mission to the Moon. This is a saved PDS data set, as opposed to a regular PDS archive. The data were recovered long after the end of the mission and are being preserved by PDS, but the documentation and supporting materials required for a regular PDS archive were not available. See Appendix G of the PDS Standards Reference for more information about saved data sets. Aggregated topographic ranges, radii, and related data were collected from the lunar surface along each observational pass during which LIDAR laser range data were acquired. The data were created using preliminary spacecraft timing, orientation, and orbital solutions. The laser ranges were converted from counts to meters using a calibration factor of 39.972 m per count. There may be substantial errors in timing information owing to spacecraft computer resets and clock ambiguity. The lidar electronics triggered on photon pulses continuously, and recorded up to four pulses within a programmable range window. The last trigger before and the first trigger after the range window were also recorded. Usually, but not always, the first trigger within the range window was the valid range. For a few laser shots, multiple pulses were detected within the expected time interval for lunar reflections. These data were used to create the CLEM1-L-LIDAR-5-TOPO-V1.0 dataset. Please see the CLEM1-L-LIDAR-5-TOPO-V1.0 dataset (http://pds-geosciences.wustl.edu/geodata/clem1-gravity-topo-v1/cl_xxxx/) for more documentation on the instrument and the experiment. 2. File Formats The Clementine lidar tables contain the laser ranges and related data for each orbit. Each row in the table contains the date/time, boresight angle, position of laser bounce points, radii, relative elevations, revolution number, range gates, and thresholds. The (delimited) data require 348 ASCII characters; these are followed by an ASCII carriage-return, and an ASCII line-feed. All tabular files are described by detached PDS labels, which are label files having the same name as the data files they describe, with the extension .LBL. For example, the file INDEX.TAB is accompanied by the detached label file INDEX.LBL in the same directory. This allows the files to be read by the MacOS, Windows, and Unix operating systems. Tabular files are formatted so that they may be read directly into many database management systems (DBMS) or spreadsheet programs on various computers. All fields are separated by commas, and character fields are enclosed in double quotation marks ("). The "start byte" and "bytes" values listed in a PDS label do not include the commas between fields or the quotation marks surrounding character fields. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. This allows a table to be treated as a fixed length record file on computers that support this file type and as a normal text file on other computers. 3. Archive Contents Files in this archive are organized into a series of subdirectories below the top-level directory. The archive organization and the contents of each directory are described below. Top-level Directory ------------------- AAREADME.TXT The file you are currently reading. DATA Directory -------------- The data files and associated PDS labels are stored in the DATA directory. INDEX Directory --------------- The INDEX directory contains a PDS index file for this archive. An index file is an ASCII table with each record (or line) in the table containing information about a single data product in archive. See the file INDXINFO.TXT for additional details. 4. Whom to Contact for Information For questions concerning this volume set, contact: PDS Geosciences Node Washington University 1 Brookings Drive, Campus Box 1169 St. Louis, MO 63130 Web Site: http://pds-geosciences.wustl.edu/ E-mail: geosci@wunder.wustl.edu For general information related to the PDS, contact: Planetary Data System, PDS Operator M/S 202-101 Jet Propulsion Laboratory 4800 Oak Grove Drive Pasadena, CA 91109-8099 (818) 354-4321 WWW Site: http://pds.jpl.nasa.gov/ E-mail: pds_operator@jpl.nasa.gov 5. Cognizant Persons This saved dataset was designed and produced at the PDS Geosciences Node, Washington University in St. Louis, Missouri by Meredith Berwick, Susan Slavney, and Jennifer Ward.