PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2011-06-30 NOTE = "AAREADME file" END_OBJECT = TEXT END AAREADME.TXT ============ In the Summer of 2011 as part of a reorganization of legacy data on physical volume, the two data sets comprising the five DVD volumes NLEROS_2001-NLEROS_2005 were reorganized into two logical volumes, one for each data set. The description below is reproduced exactly from the original AAREADME.TXT file that appeared on each of the five DVDs, and describes both data sets in their original format. Apart from splitting the data sets and renameing the directories containing the observational data files (from "LEVEL2" or "LEVEL3" to "DATA/", the structure of the logical volumes is nearly identical to the original volumes. Check the "*INFO.TXT" files for any local variations made to accommodate the modern data set organization. This volume contains only the NLR along-track profiles, data set NEAR-A-NLR-5-CDR-EROS/ORBIT-V1.0. -A.C.Raugh, 2011-06-30 _______________________________________________________________________ 1. Introduction This document provides an overview of the Near Earth Asteroid Rendezvous NLR Calibrated Level 2 data archives, and Level 3 gridded maps and spherical harmonic model archives, including a complete listing of the contents of this archive volume, below. This archive contains science data products from observations acquired by the Near Earth Asteroid Rendezvous (NEAR) NEAR Laser Rangefinder (NLR) instrument. The NLR Level 2 calibrated data products in this archive include along-track time series of the NLR instrument's science data and an observation log table containing the start times and basic parameters for the start of collection of each observation set by the NEAR NLR. Level 3 data includes binary gridded map products and spherical harmonic models. The entire Level 2 and Level 3 archive is comprised of 5 compact discs. The table below lists the individual volume (CDs) and a brief note of their respective contents. VOLUME_ID Notes --------- --------------------------------------------------- NLEROS_2001 Along-track time series data files L00059 to L00158 NLEROS_2002 Along-track time series data files L00159 to L00208 NLEROS_2003 Along-track time series data files L00209 to L00283 NLEROS_2004 Along-track time series data files L00284 to L01008 NLEROS_2005 Along-track time series data files L01009 to L01043 2. Documentation The Level 2 and Level 3 data sets are described in the files NLRL2DS.CAT and NLRL3DS.CAT, respectively, in the CATALOG directory. Also in this directory are files describing the NLR instrument (NLRINST.CAT), the NEAR spacecraft (INSTHOST.CAT) and mission (MISSION.CAT), personnel associated with this archive volume (PERSON.CAT), and a bibliography of references mentioned in these files (REF.CAT). The files in this directory will become entries in the Planetary Data System online catalog. Additional documentation is found in the DOCUMENT directory, including a document describing the NLR instrument calibrations (NLRCALIB.TXT). Early, pre-launch documents describing the NEAR mission (MISSION.PDF and MISSION.RTF) and NLR instrument (NLR.PDF and NLR.RTF) are found in the DOCUMENT/HISTORIC directory. These files are being provided for historical purposes. Most of the information in these files has been updated in the MISSION.CAT and NLRINST.CAT files in the CATALOG directory of this volume. 3. Volume Set Information Calibrated Level 2 Products The Level 2 data product comprises the along-track time series of the NLR instrument's science data in physical units, produced using precision orbits, ancillary timing and attitude information supplied by the NEAR SDC, and instrument data derived from in-flight analysis. Each Level 2 data product is a text format table corresponding to a daily level 1 EDR file, and is described by a detached label. The file naming convention is LyydddNv.TAB, where L=laser, and yyddd contains the two-digit year and the three-digit day of observation. The letter v stands for processing version. The current Level 2 versions denote the source of spacecraft ephemerides: D - reconstructed orbits provided by the JPL Navigation Team, during the initial asteroid encounter and the final descent phase. G - reconstructed orbits provided by the GSFC NLR investigation. J - GSFC orbits supplemented by JPL orbits around times of Orbit Change Maneuvers and Momentum Correction Maneuvers. There will be only one version of the data for each specific orbit. These files are stored in the LEVEL2/TOPO directory. A JPEG image representing each of these level 2 data files on the volume can be found in the BROWSE/LEVEL2 directory. There is also a single Level 2 observation log file. This table contains the start times and basic parameters for the start of collection of each observation set by the NEAR NLR. The log file is stored in the LEVEL2/LOG directory. Level 3 Products The Level 3 data products include binary gridded maps of the shape of Eros and spherical harmonic models of the shape and gravity of Eros in ASCII format. The spherical harmonic shape model is a numerical transform of a gridded shape model. The spherical harmonic models of gravity are derived from joint solutions to the altimetry and tracking data. ASCII spherical harmonic models are stored in the LEVEL3/SHA directory with file names of the form NLRknnnv.SHA, where nnn is a 3-character modifier specified by the data producer, v is a version identifier, k is replaced by G for gravity field or T for topography/shape field, and SHA denotes that this is an ASCII file of spherical harmonic coefficients. Gridded map products are stored in the LEVEL3/IMG directory. Each image is a binary array of 16-bit integers with one image line per file record. The image file name is in the form NLRnnnvk.IMG, where nnn is the bin size, v is a version identifier, and k is replaced by C for counts, and R for radius, and IMG denotes that this is a PDS image object. For example, a one-quarter degree resolution topography image would be named NLR025vR.IMG. Its format would be described by a detached PDS label in the file NLR025vR.LBL. An ASCII tabular file containing global shape data of Eros, including the latitude and longitude of the NLR laser bounce point, the radius, and the number of observations (counts) can be found in the LEVEL3/ASCII directory. A JPEG image representing each of these level 3 gridded map files on the volume can be found in the BROWSE/LEVEL3 directory. 4. CD-ROM Format The CD-ROM has been formatted so that a variety of computer systems (e.g., PC, Macintosh, and Sun) may access the data. Specifically, it is formatted according to the ISO-9660 level 2 Interchange Standard. For further information, refer to the ISO-9660 Standard Document: RF# ISO 9660- 1988, April 15, 1988. This CD-ROM does not contain any Extended Attribute Records (XAR). Thus, VAX/VMS users may have some problems accessing files on this volume. 5. File Formats The Level 2 calibrated range data are ASCII table files with detached PDS labels. The format of these files is completely described by the detached labels. The observation log file is also an ASCII table described by its corresponding detached label. The Level 3 products on this volume are the gridded map images and spherical harmonic models. The images are binary format and are completely described by information contained in the PDS detached labels. The images can be displayed using NASAview image display software, available from the PDS at no charge. NASAview can be downloaded from the PDS Web site at http://pds.jpl.nasa.gov/. The spherical harmonic models are ASCII tabular files with detached PDS labels that describe the columns in the table. All text files (*.TXT files) and detached labels (*.LBL files) on this volume are stream format files, with a carriage return (ASCII 13) and a line feed character (ASCII 10) at the end of each line. This allows the files to be read by the MacOS, DOS, and UNIX operating systems. All tabular files (*.TAB and *.SHA files) are also described by PDS detached labels. The detached PDS label file has the same name as the data file it describes, with the extension .LBL. Tabular files are formatted so that records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. Documents in the DOCUMENT/HISTORIC directory are in the proprietary Adobe Portable Document Format (PDF), which can be viewed with the free software Acrobat Reader from Adobe Systems Incorporated, and in Rich Text Format (RTF). There are JPEG images in the BROWSE directory representing the level 2 and level 3 data products. 6. Volume Contents Files on this volume are organized into a series of subdirectories below the top-level directory. The following table shows the structure and content of these directories. In the table, directory names are enclosed in square brackets ([]). FILE CONTENTS Top-level directory | |- AAREADME.TXT The file you are reading |- ERRATA.TXT Comments and errata on this volume |- VOLDESC.CAT Description of the contents of this CD-ROM | volume in object format | |- [BROWSE] Browse products (JPEG files) | | | |- [LEVEL2] Level 2 browse JPEG files | | |- LyydddNv.JPG Along-track time series data file | | |- LyydddNv.LBL Along-track time series label file | | | |- [LEVEL3] Level 3 browse JPEG files | | |- NLR125AC.JPG JPG image of gridded map of counts | | |- NLR125AC.LBL PDS label for NLR125AC.JPG | | |- NLR125AR.JPG JPG image of gridded shape map | | |- NLR125AR.LBL PDS label for NLR125AR.JPG | |- [CATALOG] PDS catalog objects | |- CATINFO.TXT Description of files in the CATALOG directory | |- DSMAP.CAT Description of map projection referenced in | | gridded image labels | |- INSTHOST.CAT Description of the NEAR spacecraft | |- MISSION.CAT Description of the NEAR mission | |- NLRINST.CAT Description of the NLR instrument | |- NLRL2DS.CAT Description of the Level-2 data set | |- NLRL3DS.CAT Description of the Level-3 data set | |- PERSON.CAT Description of personnel associated with | | production of this volume | |- REF.CAT Reference objects mentioned in *.CAT files | |- [DOCUMENT] Documentation files | |- DOCINFO.TXT Description of files in DOCUMENT directory | |- NLRCALIB.TXT NLR instrument calibration document | |- NLRCALIB.LBL PDS label for NLRCALIB.TXT | | | |- [HISTORIC] Pre-launch NEAR mission and NLR instrument | | | documents in Adobe Portable Document Format | | | and in Rich Text Format | | |- MISSION.PDF NEAR mission overview PDF document | | |- MISSION.RTF NEAR mission overview RTF document | | |- MISSION.LBL PDS label for MISSION.PDF and MISSION.RTF | | |- NLR.PDF Near Laser Rangefinder (NLR) instrument | | | overview PDF document | | |- NLR.RTF Near Laser Rangefinder (NLR) instrument | | | overview RTF document | | |- NLR.LBL PDS label for NLR.PDF and NLR.RTF | |- [INDEX] Index files | |- INDXINFO.TXT Description of files in the INDEX directory | |- L2CMIDX.LBL PDS label for L2CMIDX.TAB | |- L2CMIDX.TAB Cumulative index table of Level-2 products on | | this and preceding NLR archive volumes | |- L2INDEX.LBL PDS label for L2INDEX.TAB | |- L2INDEX.TAB Index table of Level-2 products on this volume | |- L3CMIDX.LBL PDS label for L3CMIDX.TAB | |- L3CMIDX.TAB Cumulative index table of Level-3 products on | | this and preceding NLR archive volumes | |- L3INDEX.LBL PDS label for L3INDEX.TAB | |- L3INDEX.TAB Index table of Level-3 products on this volume | |- [LEVEL2] Level 2 data files | | | |- [LOG] Observation Log data directory | | |- LOG.LBL PDS label for LOG.TAB | | |- LOG.TAB Observation log file | | | |- [TOPO] Along-Track Time Series data directory | | |- LyydddNv.TAB Along-track time series data files, where L is | | laser, yy is two-digit year, ddd is three-digit | | Julian day of observation, and v is the | | processing version | |- [LEVEL3] Level 3 data files | | | |- [ASCII] ASCII tablular data files | | |- NLR100.TAB Data file contains global shape data of Eros, | | | including the latitude and longitude of the NLR | | | laser bounce point, the radius, and the number | | | of observations (counts) | | |- NLR100.LBL PDS label for NLR100.TAB | | | |- [IMG] Gridded map data directory | | |- NLRnnnvk.IMG Gridded map data files, where nnn is the bin | | size, v is a version identifier, k is replaced | | by C for counts, and R for radius | | | |- [SHA] Spherical harmonic models data directory | | |- NLRknnnv.SHA Spherical harmonics models, where nnn is a | | 3-character modifier specified by the data | | producer, v is a version identifier and k is | | replaced by G for gravity field, and T for | | topography/shape field 7. Whom To Contact For Information For questions concerning this data set collection: PDS Geosciences Node Washington University Dept. of Earth and Planetary Sciences 1 Brookings Drive St. Louis, MO 63130 314-935-8152 WWW Site: http://pds-geophys.wustl.edu/pds Electronic mail address: jim@wuzzy.wustl.edu NEAR/NLR Science Team Code 920 NASA / Goddard Space Flight Center Greenbelt, MD 20771 WWW Site: http://ltpwww.gsfc.nasa.gov/tharsis/NLR/ Electronic mail address: Gregory.Neumann@GSFC.NASA.GOV 8. Cognizant Persons NEAR/NLR data were provided by David Smith, with assistance from Greg Neumann, both of NASA/Goddard Space Flight Center. This volume was designed and produced by Jim Alexopoulos, Planetary Data System Geosciences Node, Washington University, St. Louis, Missouri.