PDS_VERSION_ID          = PDS3
LABEL_REVISION_NOTE     = "2018-10-16 GEO:SHS Added pointer to README.TXT
                           for the PDS4 archive"
RECORD_TYPE             = STREAM
OBJECT                  = TEXT
  PUBLICATION_DATE      = 2016-05-06
  NOTE                  = "AAREADME.TXT describes this volume."
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.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. ----

MESSENGER Neutron Spectrometer CDR/DDR Archive Volume

Prepared for the Geosciences Discipline Node of the Planetary Data System

============================================================================
Introduction
============================================================================

This volume contains calibrated (CDR) and derived (DDR) data and associated 
documentation from the MESSENGER Neutron Spectrometer. This is version 2 of 
these datasets (MESS-E/V/H-GRNS-3-NS-CDR-V2.0 and 
MESS-E/V/H-GRNS-4-NS-DDR-V2.0) 

A complete description of the design of this volume is given in the NS 
CDR/DDR Software Interface Specification. An electronic copy of this 
document is located in the DOCUMENT directory.

This volume is intended for the use of scientists and students in the study
of the geography and geochemistry of the planet Mercury. The data may be
used for research and publication.

============================================================================
Volume Format
============================================================================

All science data are located in the DATA directory. The INDEX directory
contains a listing of all of the data products included on the volume. The
CATALOG directory contains PDS documentation describing the mission,
spacecraft, instrument, and data set. These include:

  MISSION.CAT              MESSENGER mission description
  INSTRUMENT_HOST.CAT      MESSENGER spacecraft description
  INST.CAT                 NS instrument description
  CDR_DS.CAT               NS calibrated data set description
  DDR_DS.CAT               NS derived data set description
  REF.CAT                  MESSENGER mission reference citations,
                           including NS references.
  PERSON.CAT               NS personnel contact information.

Additional information on volume organization is given in the CDR/DDR SIS
(described above), and in the section 'Volume Contents' below.

============================================================================
File Formats
============================================================================

The data files on this volume are provided in flat IEEE binary format
(extension .DAT) as well as ASCII table format (extension .TAB). Each data
file is also accompanied by a detached PDS label file (extension .LBL), an
ASCII file containing information describing the data file and data record
format.

Catalog files (extension .CAT) are provided in ASCII format.

Document files describing the volume and the data are given in ASCII and PDF
formats.

Text files and detached label files contain 80-byte fixed-length ASCII
records, with a carriage-return character (ASCII 13) in the 79th byte and a
line-feed character (ASCII 10) in the 80th byte. This format allows the
files to be read by MacOS, DOS, UNIX and VMS operating systems. Note that
while both label and catalog files are ASCII, some operating systems will
not recognize the .LBL and .CAT extensions as ASCII types. It may be
necessary to either remap these extensions as ASCII in the system or text
browser, or else to open the files from within the text browser.

============================================================================
Volume Contents
============================================================================

Directory Structure and Contents for NS CDR/DDR Archive Volume

The following illustration shows the directory structure overview for the NS
CDR/DDR archive volume, which bears the PDS-assigned volume ID MESSNS_2101. 
The complete archive volume was delivered to PDS with the first release of 
NS CDR/DDR products. Subsequent deliveries of NS CDR/DDR products consisted 
of a partial volume containing only new and changed files.


Directory Structure Overview

                                    <ROOT>                                  
 ______________________________________|____________________________________
     |         |           |           |           |          |         |   
<CATALOG>   <CALIB>   <DOCUMENT>    <DATA>    <GEOMETRY>   <LABEL>   <INDEX>
                   ____________________|____________________                
                    |                                     |                 
                    |                                     |                 
                  <CDR>                                 <DDR>               
                    |                                     |                 
____________________|_____      __________________________|_________________
  |       |            |         |       |            |       |             
  |       |            |         |       |            |       |             
<2004>  <2005>...   <2010>     <2004>  <2005>...   <2010>    NS_DDR_NCP.TAB 
  |                              |                           NS_DDR_NCP.LBL 
__|_______________________     __|_______________________                   
  |       |            |         |       |            |                     
 <01>    <02>...      <12>     <01>    <02>...       <12>   


Directory Contents:

<ROOT> Directory

This is the top-level directory of the data volume. The following are files
contained in the root directory.

AAREADME.TXT: (This file) General information file. Provides users with
information about the MESSENGER NS data products. Directs user to other
documents on the volume containing more detailed information.

VOLDESC.CAT: PDS file containing the VOLUME object. This gives a high level
description of the contents of the volume. Information includes: production
date, producer name and institution, volume ID, etc.

ERRATA.TXT: Text file for identifying and describing errors and/or anomalies
found in the current volume, and possibly previous volumes of a set. Any
known errors for the associated volume are documented in this file.
This includes revised CDRs/DDRs meant to replace CDRs/DDRs in a previous PDS 
delivery.


<CATALOG> Directory

This subdirectory contains the catalog object files for the entire volume.
The following files are included in the catalog subdirectory.

CATINFO.TXT: Identifies and describes of function of each file in the
catalog directory.

CDR_DS.CAT: Describes the general content of the CDR data set and includes 
information about the duration of the mission and the person or group 
responsible for producing the data. 

DDR_DS.CAT: Describes the general content of the DDR data set and includes 
information about the duration of the mission and the person or group 
responsible for producing the data. 

NS_INST.CAT: Describes physical attributes of the NS instrument and provides
relevant references to published literature.

INSTRUMENT_HOST.CAT: Describes the MESSENGER spacecraft.

MISSION.CAT: Describes the scientific goals and objectives of the MESSENGER
program. It also identifies key people and institutions.

PERSON.CAT: Lists and provides contact information for the people involved
with the NS instrument on the MESSENGER mission.

REF.CAT: Provides references (reference objects) to scientific papers and
other publications of interest to those using the data, both for NS and the
mission as a whole.


<CALIB> Directory

CALINFO.TXT: Description of calibration directory files.

MESSNS_PROCESSING.TXT: 'MESSENGER Neutron Spectrometer EDR-to-CDR-to-DDR 
Processing' document in ASCII text format.                               
                                                                              
MESSNS_PROCESSING.PDF: 'MESSENGER Neutron Spectrometer EDR-to-CDR-to-DDR 
Processing' document in Adobe Acrobat format.                            
                                                                              
MESSNS_PROCESSING.LBL: The detached label for the two MESSNS_EDR2CDR2DDR 
files.


<DOCUMENT> Directory

This subdirectory contains the documentation that is needed in order to
understand and analyze the CDR/DDR data products. Files are stored in 
PDF and ASCII format.

DOCINFO.TXT: Identifies and describes the function of each file in the
DOCUMENT directory.

NS_CDR_DDR_SIS.TXT: The NS CDR/DDR SIS: "MESSENGER Neutron Spectrometer 
Calibrated and Derived Data Record Software Interface Specification" in 
ASCII text format. Only the text is provided; for illustrations, tables, 
etc., the PDF should be consulted.                                            
                                                                              
NS_CDR_DDR_SIS.PDF: The NS CDR/DDR SIS: "MESSENGER Neutron Spectrometer 
Calibrated and Derived Data Record Software Interface Specification" in 
Adobe Acrobat format.  Note that, in contrast to the .TXT version, the 
illustrations, tables, etc. will display appropriately. 

NS_CDR_DDR_SIS.LBL: The detached label for the two NS CDR/DDR SIS files.


<DATA> Data Directory

This is the top level of the directories in which the CDRs and DDRs are 
contained. The CDRs and DDR NCRs reside in data directories organized by 
year (YYYY) followed by month (MM). The DDR NCP is located at the DDR 
directory level.


<GEOMETRY> Directory

GEOMINFO.TXT: Description of geometry directory files. See Appendix 7.1 in
NS CDR/DDR SIS.


<LABEL> Label Directory

This subdirectory contains the format files for each of the different CDR 
and DDR product types. The format file describes the format of the Binary 
and ASCII Table objects in the CDR/DDR data files. There is no format file 
associated with the DDR NCP.

LABINFO.TXT: Identifies and describes the function of each file in the label
subdirectory.

NS_CDR_SPECTRA.FMT: Format file for the NS_CDR_SPECTRA standard data 
products.

NS_CDR_COUNTS.FMT: Format file for the NS_CDR_COUNTS standard data 
products.

NS_CDR_GCR_SPECTRA.FMT: Format file for the NS_CDR_GCR_SPECTRA standard data 
products.

NS_CDR_ENG.FMT: Format file for the NS_CDR_ENG standard data products.

NS_CDR_GAB.FMT: Format file for the NS_CDR_GAB standard data products.

NS_DDR_NCR.FMT: Format file for the NS_DDR_NCR standard data products.


<INDEX> Directory

This subdirectory contains the indices for the NS CDR and DDR data 
products. The following files are contained in the index subdirectory.

INDXINFO.TXT: Identifies and describes the function of each file in the
index subdirectory. This includes a description of the structure and
contents of each index table in the subdirectory and usage notes.

CDR_INDEX.TAB: The CDR index file is organized as a table. In the table, 
there is a row for each CDR data product on the volume. The table columns 
contain parameters that describe the observation, instrument, and spacecraft 
parameters.

CDR_INDEX.LBL: Detached PDS label for CDR_INDEX.TAB. It contains the 
INDEX_TABLE object which identifies and describes the columns of the NS 
index table.

DDR_INDEX.TAB: The DDR index file is organized as a table. In the table, 
there is a row for each DDR data product on the volume. The table columns 
contain parameters that describe the observation, instrument, and spacecraft 
parameters. 

DDR_INDEX.LBL: Detached PDS label for DDR_INDEX.TAB. It contains the 
INDEX_TABLE object which identifies and describes the columns of the NS 
index table. 

MD5.TAB: Provides the MD5 checksum (message digest) for each file in the      
archive, with the exception of the MD5.TAB file itself.                       
                                                                              
MD5.LBL: Detached PDS label for MD5.TAB.


============================================================================
Related PDS Products
============================================================================

The NS CDR and DDR data sets are derived from the NS EDR data set 
(PDS Data Set ID MESS-E/V/H-GRNS-2-NS-RAWDATA-V1.0, volume ID MESSNS_1001). 
All NS data sets are available from the Planetary Data System 
(http://pds.nasa.gov). 

============================================================================
Errata
============================================================================

Every effort has been made to ensure that the data and documentation are
of the best possible quality. However, all users are encouraged to
verify the correctness of the data prior to submitting any publications
or other work based on these data.

The file ERRATA.TXT at the root level of this volume contains a list of known
deficiencies or caveats associated with data on this volume at the time it was
published, if any. It also lists  any revisions that have been made to the
data set as a whole or to individual products.

If you find an error on this volume, please report the error to the PDS
Geosciences Node at geosci@wunder.wustl.edu.


============================================================================
Contacts
============================================================================

For questions concerning these data products and documentation, contact:

          PDS Geosciences Node
          Washington University
          Dept. of Earth and Planetary Sciences
          1 Brookings Drive
          St. Louis, MO 63130
          314-935-5493

          WWW Site:  http://pds-geosciences.wustl.edu
          Electronic mail address:  geosci@wunder.wustl.edu


For questions regarding PDS Standards or other archive volumes available
from the PDS, please contact PDS Operator at the PDS Central Node (at JPL):


    Internet            pds_operator@jpl.nasa.gov
    Telephone           (818) 354-4321
    U.S. Mail           Planetary Data System, PDS Operator
                        Jet Propulsion Laboratory
                        Mail Stop 202-101
                        4800 Oak Grove Dr.
                        Pasadena, CA 91109-8099