PDS_VERSION_ID          = PDS3
RECORD_TYPE             = STREAM
OBJECT                  = TEXT
  PUBLICATION_DATE      = 2017-05-12
  NOTE                  = "AAREADME.TXT describes this volume, 
                           MESSMAS_2101."
END_OBJECT              = TEXT
END

MESSENGER Mercury Atmospheric and Surface Composition Spectrometer (MASCS)
Ultraviolet and Visible Spectrometer (UVVS) and Visible And Infrared
Spectrograph (VIRS) Calibrated and Derived Data Archive

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

This volume contains calibrated (CDR) and derived (DDR, DAP) data from both 
detectors on the Mercury Atmospheric and Surface Composition Spectrometer 
(MASCS) instrument, the Ultraviolet and Visible Spectrometer (UVVS) and the 
Visible And Infrared Spectrograph (VIRS). This is a new volume 
(MESSMAS_2101). Most of the files on this volume improve on the previously 
released products, however the older volume (MESSMAS_2001) remains available 
in PDS.

These data sets are fully described by Software Interface Specification
documents in the DOCUMENT directory of this volume, in the files 
UVVS_CDR_DDR_SIS.*, VIRS_CDR_DDR_DAP_SIS.*, and 
UVVS_VIRS_COMBINED_DDR_SPEC.*.

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 under 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 sets. These include:

  MISSION.CAT              MESSENGER mission description
  INSTHOST.CAT             MESSENGER spacecraft description
  INST.CAT                 MASCS instrument description
  UVVS_CDR_DS.CAT          MASCS UVVS calibrated data record data set 
                           description
  VIRS_CDR_DS.CAT          MASCS VIRS calibrated data record data set 
                           description
  UVVS_DDR_DS.CAT          MASCS UVVS derived data record data set 
                           description
  VIRS_DDR_DS.CAT          MASCS VIRS derived data record data set 
                           description
  VIRS_DAP_DS.CAT          MASCS VIRS derived analysis product data set 
                           description
  UVVS_VIRS_DDR_DS.CAT     MASCS UVVS+VIRS combined derived data record 
                           data set description
  DAP_MAP.CAT              DAP data set projection description
  REF.CAT                  MESSENGER mission reference citations,
                           including MASCS/VIRS and MASCS/UVVS references
  PERSON.CAT               MASCS personnel contact information


Additional information on volume organization is given in the CDR/DDR/DAP 
SIS documents mentioned above and in the section 'Volume Contents' below.

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

The data files on this volume are provided in IEEE binary format (extension 
.DAT) and image format (extension .IMG). 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 
Adobe PDF formats.

Text files and detached label files contain ASCII records terminated with
a carriage-return character (ASCII 13) and a line-feed character (ASCII 10).
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 MASCS CDR/DDR/DAP Data Archive Volume

The following illustration shows the directory structure overview for the
MASCS CDR/DDR/DAP archive volume, which bears the PDS-assigned volume ID 
MESSMAS_2101. This volume contains the MASCS VIRS and UVVS CDR, DDR, and DAP 
data products, supporting documentation, and any additional files required 
for the volume to be compliant with PDS standards. The content of the volume 
was updated with periodic releases according to the schedule found in the 
MESSENGER Data Management and Archiving Plan (DMAP, see Applicable Document 
4 listed in DOCUMENT/*SIS.PDF). Revised CDRs/DDRs/DAPs were delivered 
according to the same schedule. Revised CDRs/DDRs/DAPs have an incremented 
version number in the PDS label.


Directory Structure Overview

                             <ROOT>                                     
_______________________________|_______________________________________ 
    |          |        |      |        |         |       |       |     
<DOCUMENT> <CATALOG> <INDEX> <DATA> <GEOMETRY> <CALIB> <LABEL> <EXTRAS> 
                               |                                        
                   ____________|____________                            
                    |          |         |                              
                  <CDR>      <DDR>     <DAP>                            
                    |          |         |                              
            <mission phase> [Fig. A]   <VIRS>                           
                    |                                                   
                    |                                                   
             <MASCSYYYYMMDD>                                            
                    |                                                   
             _______|_______                                            
             |             |                                            
           <UVVS>        <VIRS>                                         
             |             |                                            
    _________|___       ___|___                                         
    |    |      |       |     |                                         
   FUV  MUV    VIS     VIS   NIR                                        
                                                                        
                                                                        
[Fig. A]                                                                 
                                    <DDR>                                    
                                      |                                      
                                      |                                      
                               <mission phase>                               
                                      |                                      
______________________________________|___________________________________   
   |                 |                |               |              |       
<UVVS_             <UVVS_           <UVVS_          <UVVS_         <VIRS>    
ATMOSPHERE>        SUMMARY_         SURFACE>        VIRS_            |       
   |               ATMOSPHERE>         |            COMBINED>        |       
___|_____________      |               |                |            |       
   |         |         |        <MASCSYYYYMMDD>         |     <MASCSYYYYMMDD>
<models> <mercury  <species>           |                |            |       
          year>        |            ___|___             |         ___|____   
                       |            |     |             |          |    |    
                   <mercury        FUV   MUV     <MASCSYYYYMMDD>  VIS  NIR   
                    year>                                                    

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 MASCS 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/DAPs meant to replace CDRs/DDRs/DAPs in a previous 
PDS delivery.


<DOCUMENT> Directory

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

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

UVVS_CDR_DDR_SIS.TXT: The MASCS UVVS CDR/DDR SIS: "MESSENGER MASCS UVVS 
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.

UVVS_CDR_DDR_SIS.PDF: The MASCS UVVS CDR/DDR SIS: "MESSENGER MASCS UVVS 
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.

UVVS_CDR_DDR_SIS.LBL: A detached PDS label that describes the text and PDF 
files.

VIRS_CDR_DDR_DAP_SIS.TXT: The MASCS VIRS CDR/DDR/DAP SIS: "MESSENGER MASCS 
VIRS Calibrated Data Record, Derived Data Record, and Derived Analysis 
Product Software Interface Specification" in ASCII text format. Only the 
text is provided; for illustrations, tables, etc. the PDF should be 
consulted.

VIRS_CDR_DDR_DAP_SIS.PDF: The MASCS VIRS CDR/DDR/DAP SIS: "MESSENGER MASCS 
VIRS Calibrated Data Record, Derived Data Record, and Derived Analysis 
Product Software Interface Specification" in Adobe Acrobat format. Note 
that, in contrast to the .TXT version, the illustrations, tables, etc. will 
display appropriately.

VIRS_CDR_DDR_DAP_SIS.LBL: A detached PDS label that describes the text and 
PDF files.

UVVS_VIRS_COMBINED_DDR_SPEC.TXT: The MASCS UVVS/VIRS COMBINED DDR 
Specification: "MESSENGER MASCS UVVS+VIRS Combined Derived Data Record 
Specification" in ASCII text format. Only the text is provided; for 
illustrations, tables, etc. the PDF should be consulted.

UVVS_VIRS_COMBINED_DDR_SPEC.PDF: The MASCS UVVS/VIRS COMBINED DDR 
Specification: "MESSENGER MASCS UVVS+VIRS Combined Derived Data Record 
Specification" in Adobe Acrobat format. Note that, in contrast to the .TXT 
version, the illustrations, tables, etc. will display appropriately.

UVVS_VIRS_COMBINED_DDR_SPEC.LBL: A detached PDS label that describes the 
text and PDF files.

UVVS_EDR2CDR.TXT: Detailed procedures and tables for EDR to CDR calibration.

UVVS_EDR2CDR.LBL: The detached label for the UVVS calibration document.

VIRS_EDR2CDR.TXT: Detailed procedures and tables for EDR to CDR calibration.

VIRS_EDR2CDR.LBL: The detached label for the VIRS calibration document.

UVVS_CDR2DDR.TXT: Detailed procedures and tables for CDR to Atmosphere DDR 
data reduction. 

UVVS_CDR2DDR.LBL: The detached label for the CDR to Atmosphere DDR document.

UVVS_CDR2DDR_SUR.TXT: Detailed procedures and tables for CDR to Surface DDR 
data reduction. 

UVVS_CDR2DDR_SUR.LBL: The detached label for the CDR to Surface DDR document.

UVVSVIRS_DDR2DDR_COMBINED.TXT: Detailed procedures for UVVS-VIRS DDR to 
Combined DDR data reduction.

UVVSVIRS_DDR2DDR_COMBINED.LBL: The detached label for the UVVS-VIRS DDR to 
Combined DDR document.

VIRS_CDR2DDR.TXT: Detailed procedures and tables for CDR to DDR data 
reduction. 

VIRS_CDR2DDR.LBL: The detached label for the CDR to DDR document.

MASCS_CAL_RPT.TXT: The MESSENGER instrument calibration report for MASCS, in 
ASCII text format. Only the text is provided; for illustrations, tables, 
etc. the PDF should be consulted.

MASCS_CAL_RPT.PDF: The MESSENGER instrument calibration report for MASCS, in 
Adobe Acrobat format.  Note that, in contrast to the .TXT version, the 
illustrations, tables, etc. will display appropriately.

MASCS_CAL_RPT.LBL: A detached PDS label that describes the text and PDF 
files.

VIRS_DARK_ANALYSIS_REPORT_1.PDF: "VIRS IR Dark Analysis Report 1: 
Operational Changes" in Adobe Acrobat format. Details the evolving 
understanding of MASCS dark current during Mercury orbit, describing 
temperature dependence and effects on the NIR data in particular. Note that, 
in contrast to the .TXT version, the illustrations, tables, etc. will 
display appropriately.

VIRS_DARK_ANALYSIS_REPORT_1.TXT: "VIRS IR Dark Analysis Report 1: 
Operational Changes" in ASCII text format. Details the evolving 
understanding of MASCS dark current during Mercury orbit, describing 
temperature dependence and effects on the NIR data in particular. Only the 
text is provided; for illustrations, tables, etc. the PDF should be 
consulted.

VIRS_DARK_ANALYSIS_REPORT_1.LBL: A detached PDS label that describes the 
text and PDF file.

VIRS_DARK_ANALYSIS_REPORT_2.PDF: "VIRS IR Dark Analysis Report 2: 
Calibration Changes" in Adobe Acrobat format. Describes the adjustments to 
MASCS calibration to improve dark subtraction and account for pixels 
saturated due to temperature. Note that, in contrast to the .TXT version, 
the illustrations, tables, etc. will display appropriately.

VIRS_DARK_ANALYSIS_REPORT_2.TXT: "VIRS IR Dark Analysis Report 2: 
Calibration Changes" in ASCII text format. Describes the adjustments to 
MASCS calibration to improve dark subtraction and account for pixels 
saturated due to temperature. Only the text is provided; for illustrations, 
tables, etc. the PDF should be consulted.

VIRS_DARK_ANALYSIS_REPORT_2.LBL: A detached PDS label that describes the 
text and PDF file.

UVVS_CALIBRATION_CHANGES_PDS7.PDF: "UVVS Calibration Changes for PDS 
Delivery 7" in Adobe Acrobat format. Describes the need for and method of 
removing solar background signal in several emission wavelength regions. 

UVVS_CALIBRATION_CHANGES_PDS7.TXT: "UVVS Calibration Changes for PDS 
Delivery 7" in ASCII text format. Describes the need for and method of 
removing solar background signal in several emission wavelength regions. 

UVVS_CALIBRATION_CHANGES_PDS7.LBL: A detached PDS label that describes the 
text and PDF file.

VIRS_CALIBRATION_CHANGES_PDS9.PDF: "VIRS Calibration Changes for PDS 
Delivery 9" in Adobe Acrobat format. Describes the calibration changes 
implemented to simplify the handling of dark subtractions for VIRS, and an 
adjustment to the DATA_QUALITY_INDEX provided in the data records.

VIRS_CALIBRATION_CHANGES_PDS9.TXT: "VIRS Calibration Changes for PDS 
Delivery 9" in ASCII text format. Describes the calibration changes 
implemented to simplify the handling of dark subtractions for VIRS, and an 
adjustment to the DATA_QUALITY_INDEX provided in the data records. 

VIRS_CALIBRATION_CHANGES_PDS9.LBL: A detached PDS label that describes the 
text and PDF file.

UVVS_CALIBRATION_CHANGES_PDS11.PDF: "MESSENGER MASCS UVVS Calibration Update 
- PDS 11" in Adobe Acrobat format. Describes the UVVS FUV CDR calibration 
sensitivity update. 

UVVS_CALIBRATION_CHANGES_PDS11.TXT: "MESSENGER MASCS UVVS Calibration Update 
- PDS 11" in ASCII text format. Describes the UVVS FUV CDR calibration 
sensitivity update. 

UVVS_CALIBRATION_CHANGES_PDS11.LBL: A detached PDS label that describes the 
text and PDF file.

VIRS_CALIBRATION_CHANGES_PDS11.PDF: "VIRS Calibration Changes for PDS 
Delivery 11" in Adobe Acrobat format. Describes changes to the calibration 
procedure that have been implemented to remedy an observed shift in the 
wavelength scale of the VIRS visible channel. 

VIRS_CALIBRATION_CHANGES_PDS11.TXT: "VIRS Calibration Changes for PDS 
Delivery 11" in ASCII text format. Describes changes to the calibration 
procedure that have been implemented to remedy an observed shift in the 
wavelength scale of the VIRS visible channel. 

VIRS_CALIBRATION_CHANGES_PDS11.LBL: A detached PDS label that describes the 
text and PDF file.

CALCIUM_CHAMBERLAIN_MODELS.PDF: Description of the calcium Chamberlain 
models in Adobe Acrobat format.

CALCIUM_CHAMBERLAIN_MODELS.TXT: Description of the calcium Chamberlain 
models in ASCII text format. Only the text is provided; for equations, 
tables, etc. the PDF should be consulted.

CALCIUM_CHAMBERLAIN_MODELS.LBL: A detached PDS label that describes the 
text and PDF file.

UVVS_PROCESSING_UPDATES_PDS16.PDF: "MESSENGER MASCS UVVS Processing Updates 
- PDS 16" in Adobe Acrobat format. Describes the UVVS CDR and DDR processing 
updates for PDS delivery 16.  

UVVS_PROCESSING_UPDATES_PDS16.TXT: "MESSENGER MASCS UVVS Processing Updates 
- PDS 16" in ASCII text format. Describes the UVVS CDR and DDR processing 
updates for PDS delivery 16. 

UVVS_PROCESSING_UPDATES_PDS16.LBL: A detached PDS label that describes the 
HTML and PDF file.

VIRS_FLATFIELD_REPORT.PDF: "MASCS/VIRS Lamp-Based Flat Field Report" in Adobe 
Acrobat Format. Describes the results of an investigation to derive a 
flat-field correction for the MASCS VIRS surface observations.

VIRS_FLATFIELD_REPORT.HTM: "MASCS/VIRS Lamp-Based Flat Field Report" in HTML 
Format. Describes the results of an investigation to derive a flat-field 
correction for the MASCS VIRS surface observations.

VIRS_FLATFIELD_REPORT.LBL: A detached PDS label that describes the HTML and 
PDF file.

VIRS_TUTORIAL.PDF: MASCS VIRS Tutorial/User's Guide in PDF/A format.

VIRS_TUTORIAL.LBL: A detached PDS label that describes the PDF/A file.


<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.

UVVS_CDR_DS.CAT, VIRS_CDR_DS.CAT: Describes the general content of the 
MASCS UVVS and MASCS VIRS CDR datasets, and includes information about the 
duration of the mission and the person or group responsible for producing 
the data.

UVVS_DDR_DS.CAT, VIRS_DDR_DS.CAT: Describes the general content of the 
MASCS UVVS and MASCS VIRS DDR datasets, and includes information about the 
duration of the mission and the person or group responsible for producing 
the data. 

VIRS_DAP_DS.CAT: Describes the general content of the MASCS VIRS DAP 
dataset, and includes information about the duration of the mission and the 
person or group responsible for producing the data.

UVVS_VIRS_DDR_DS.CAT: Describes the general content of the MASCS UVVS+VIRS 
Combined DDR dataset.

DAP_MAP.CAT: Describes the DAP dataset equirectangular map projection.

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

INSTHOST.CAT: Describes the MESSENGER spacecraft.

MISSION.CAT: Describes the scientific goals and objectives of the MESSENGER 
program.

REF.CAT: Contains the complete citations of references mentioned in the
above catalog files, along with citations of additional documents that may 
be useful to the person using the MASCS CDR/DDR/DAP data.

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


<INDEX> Directory

This subdirectory contains the indices for the MASCS CDR/DDR/DAP 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.

VICINDEX.TAB: The VIRS CDR index file is organized as a table. There is one 
entry for each of the data files included in the VIRS CDR data set. The 
columns contain parameters that describe the observation, instrument, and 
spacecraft parameters.

VICINDEX.LBL: Detached PDS label for VICINDEX.TAB.

VIDINDEX.TAB: The VIRS DDR index file is organized as a table: there is one 
entry for each of the data files included in the VIRS DDR data set; the 
columns contain parameters that describe the observation, instrument, and 
spacecraft parameters. 

VIDINDEX.LBL: Detached PDS label for VIDINDEX.TAB.

VDAPINDEX.TAB: The VIRS DAP index file is organized as a table: there is one 
entry for each of the data files included in the VIRS DAP data set; the 
columns contain parameters that describe the observation, instrument, and 
spacecraft parameters.

VDAPINDEX.LBL: Detached PDS label for VDAPINDEX.TAB.

UHCINDEX.TAB: The UVVS CDR header index file is organized as a table. There 
is one entry for each of the UVVS header files included in the UVVS data 
set. The columns contain parameters that describe the observation, 
instrument, and spacecraft parameters.

UHCINDEX.LBL: Detached PDS label for UHCINDEX.TAB.

USCINDEX.TAB: The UVVS CDR science index file is organized as a table. There 
is one entry for each of the UVVS science data files included in the UVVS 
data set. The columns contain parameters that describe the observation, 
instrument, and spacecraft parameters.

USCINDEX.LBL: Detached PDS label for USCINDEX.TAB.

USDINDEX.TAB: The UVVS DDR science index file is organized as a table: there 
is one entry for each of the data files included in the UVVS DDR data set; 
the columns contain parameters that describe the observation, instrument, 
and spacecraft parameters. 

USDINDEX.LBL: Detached PDS label for USDINDEX.TAB.

UVDINDEX.TAB: The UVVS+VIRS Combined DDR index file is organized as a table: 
there is one entry for each of the data files included in the UVVS+VIRS 
Combined DDR data set; the columns contain parameters that describe the 
observation, instrument, and spacecraft parameters. 

UVDINDEX.LBL: Detached PDS label for UVDINDEX.TAB.

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.


<GEOMETRY> Directory

This subdirectory contains information about the files (e.g. SPICE kernels, 
etc) needed to determine the observation geometry for the data.

GEOMETRY.TXT: Identifies and describes the SPICE kernels that a user must 
have in order to determine observation geometry for the data. The SPICE 
kernel files are archived with the PDS NAIF node.


<CALIB> Directory

This subdirectory contains a look up table for calibration.

CALINFO.TXT: Describes the contents of this directory.

UVVS_GRATING_OFFSET.TAB: Time tag table of UVVS grating offsets. A grating 
offset correction was implemented for PDS Release 16. This table is a record 
of the time periods relevant to and the magnitudes (in grating steps) of the 
offsets.

UVVS_GRATING_OFFSET.LBL: Detached PDS label for UVVS_GRATING_OFFSET.TAB.


<LABEL> Directory

This subdirectory contains format files (label fragments) that are
referenced in the PDS labels for data files. These format files define the
structure and contents of the binary data tables. Software that interprets
PDS labels automatically includes these files to determine how to read the 
data.

LABINFO.TXT: Describes this directory.

UVVSHDRC.FMT: Format of the UVVS CDR science header table.

UVVSSCIC.FMT: Format of the UVVS CDR science data table. 

UVVSSCID.FMT: Format of the UVVS atmosphere science DDR data table. 

UVVSSUMD.FMT: Format of the UVVS atmosphere summary DDR data table.

UVVSHDRD_SUR.FMT: Format of the UVVS surface header DDR data table. 

UVVSSCID_SUR.FMT: Format of the UVVS MUV surface science DDR data table.

UVVSSCID_FUV_SUR.FMT: Format of the UVVS FUV surface science DDR data table.

VIRSVC.FMT: Format of the VIRS VIS (visible wavelength) CDR data table.

VIRSNC.FMT: Format of the VIRS NIR (near infrared wavelength) CDR data 
table.

VIRSVD.FMT: Format of the VIRS VIS (visible wavelength) DDR data table.

VIRSND.FMT: Format of the VIRS NIR (near infrared wavelength) DDR data 
table.

UVVSVIRSD.FMT: Format of the UVVS+VIRS Combined DDR data table.


<EXTRAS> Directory 

This subdirectory contains ancillary material that may be useful but is not 
required for the understanding of the archive.

VIRS_AV/: This subdirectory contains the VIRS animated visualization 
products, organized by mission phase and provided in .MP4 format. 
VIRS_AV_DESCRIPTION.PDF describes these products in detail.

MASTER_CRUISE_TABLE.XLS: This is an extended instrument operation table 
used during cruise and flyby operations of MASCS, showing details of VIRS 
and UVVS observations, times, and other information useful for quick
reference. In orbit, the mission planning software SCIBOX takes over the 
function of this table. This file can be viewed using Microsoft Excel.

VIRS_CDR_EXCLUDED.TXT: This is a list of VIRS CDRs that are excluded from 
PDS delivery due to bad dark solutions. See VIRS_CDR_DS.CAT for more 
information.

VIRS_DDR_EXCLUDED.TXT: This is a list of VIRS DDRs that are excluded from 
PDS delivery due to
1) all footprints have shutter closed
2) all footprints are off planet
3) all footprints are in nightside shadow
4) bad dark solutions
See VIRS_DDR_DS.CAT for more information.

VIRS_MISSING_PACKETS_R6.TXT: This file describes the investigation and 
resolution of the missing packet error described in the "Data Coverage and 
Quality" section of VIRS_CDR_DS.CAT. Included is a list of the EDRs (and thus 
also CDRs) missing packets for PDS release 6. 

VIRS_VIS_EDR_MISSING_PACKET_ANALYSIS_R6.XLS: This is a companion spreadsheet 
to the file above. It shows a detailed breakdown of the EDRs and exactly 
which packets are missing.

VIRS_VIS_MISSING_PACKETS_R*.TXT: These files list the incomplete VIRS VIS 
EDRs/CDRs for PDS releases, where '*' is the release #. The errors are 
described in the "Data Coverage and Quality" section of VIRS_CDR_DS.CAT.  

VIRS_NIR_MISSING_PACKETS_R*.TXT: These files list the incomplete VIRS NIR 
EDRs/CDRs for PDS releases, where '*' is the release #. The errors are 
described in the "Data Coverage and Quality" section of VIRS_CDR_DS.CAT. 


<DATA> Data Directory

This is the top level directory for the data products. Directly underneath 
the <DATA> directory are the <CDR>, <DDR>, and <DAP> directories. Below the 
<DAP> directory is the <VIRS> subdirectory, wherein lies the VIRS DAP images 
(*.IMG) and associated PDS label (*.LBL). Below the <CDR> and <DDR> 
directories are the three-letter "mission phase" subdirectories, where:

         EAC = Earth cruise to Earth flyby
         EAF = Earth flyby
         VC1 = cruise, post Earth flyby to pre-Venus 1 flyby
         VF1 = Venus 1 flyby
         VC2 = cruise, post Venus 1 to pre-Venus 2 flyby
         VF2 = Venus 2 flyby 
         MC1 = cruise, post Venus 2 to pre-Mercury 1 flyby
         MF1 = Mercury 1 flyby
         MC2 = cruise, post Mercury 1 to pre-Mercury 2 flyby
         MF2 = Mercury 2 flyby
         MC3 = cruise, post Mercury 2 to pre-Mercury 3 flyby
         MF3 = Mercury 3 flyby
         MC4 = cruise, post Mercury 3 to pre-orbit insertion
         ORB = orbit insertion until end of nominal orbit mission
         OB2 = extended mission (orbit year 2)
         OB3 = extended mission (orbit year 3)
         OB4 = extended mission (orbit year 4)
         OB5 = extended mission (orbit year 5)

For the CDRs, below the mission phase directories are the <MASCSYYYYMMDD> 
directories, where the "YYYYMMDD" characters define the four-digit year, 
2-digit month, 2-digit day which is common to all the MET times for the CDRs 
stored in that directory. The <MASCSYYYYMMDD> directories are further 
subdivided into two subdirectories, <UVVS> and <VIRS>.  The <UVVS> 
subdirectory is divided into the detector subdirectories <FUV>, <MUV>, and 
<VIS> and the <VIRS> subdirectory into <VIS> and <NIR>. Within the detector 
subdirectories are the CDR data files themselves (*.DAT) and, for each CDR 
data file, a detached label file (*.LBL). Subdirectories only exist if that 
particular type of data exists for that day. If there are no data of a 
particular type for a particular day, no subdirectory is included for that 
type.

For the DDRs, below the mission phase directories are the <UVVS_ATMOSPHERE>, 
<UVVS_SUMMARY_ATMOSPHERE>, <UVVS_SURFACE>, <UVVS_VIRS_COMBINED>, and <VIRS> 
directories. The <UVVS_ATMOSPHERE> directory is further subdivided into 
directories based on the Mercury year of data acquisition (01-04 for primary 
mission, 05+ for extended mission). The <UVVS_SUMMARY_ATMOSPHERE> directory 
is subdivided into species directories which are further subdivided into 
directories based on Mercury year. Each of the <UVVS_SURFACE>, 
<UVVS_VIRS_COMBINED>, and <VIRS> directories is subdivided into 
<MASCSYYYYMMDD> date directories. The VIRS directories are further 
subdivided into <VIS> and <NIR> detector subdirectories following the 
structure of the VIRS CDRs. The <UVVS_SURFACE> directories are further 
subdivided into <FUV> and <MUV> detector subdirectories. Within the Mercury 
year (<UVVS_ATMOSPHERE>, <UVVS_SUMMARY_ATMOSPHERE>), date 
(<UVVS_VIRS_COMBINED>), and detector (<UVVS_SURFACE>, <VIRS>) subdirectories 
are the UVVS and VIRS DDR data files themselves (*.DAT), and, for each DDR 
data file, a detached label file (*.LBL). The atmospheric model data (*.TAB) 
and associated PDS labels (*.LBL) are located in the <models> directory 
beneath <ORB/UVVS_ATMOSPHERE>.

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

The MASCS UVVS/VIRS EDR volume (MESSMAS_1001) from which these 
CDRs/DDRs/DAPs were generated is available on the PDS website 
(http://pds.jpl.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, 
using the contact information below.

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

For questions concerning VIRS 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 concerning UVVS data products and documentation, contact:

          PDS Atmospheres Node                                   
          Astronomy Department                                                
          New Mexico State University                                         
          P.O. Box 30001, Dept 4500                                           
          Las Cruces, NM 88003                                                
                                                                              
          WWW Site:  http://pds-atmospheres.nmsu.edu                          
          Electronic mail address:  rbeebe@nmsu.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