Neutron Spectrometer (NS) Calibrated and Derived Data
MESSENGER Mission to Mercury

This bundle contains the following collections:

data_cdr - calibrated data products
data_ddr - derived data products
document - the NS CDR/DDR Software Interface Specification and other relevant documents
miscellaneous - the PDS3 index table for this archive

This PDS4 bundle has been migrated from a PDS3 data volume. For details, see the document
geo_notes_and_errata.pdf in the document collection.

Each document and data product in this bundle is described by a PDS4 label in a separate file with 
the same name but with the extension XML. PDS4 labels are XML (eXtended Markup Language) files that 
conform to the PDS4 Information Model XML schema at https://pds.nasa.gov/pds4/schema/released/. 
They are best viewed in an XML-aware text editor, and may be used by software that can manipulate 
XML documents.

The MESSENGER NS calibrated product collection consists of NS data that have been calibrated for
instrument and geometrical effects. There are five product types in this collection that include
spectra from the three instrument detectors, along with count rate data, gamma burst, galactic
cosmic ray spectra, and engineering data. In addition, products contain spacecraft navigation and
attitude data derived from SPICE files, as well as selected relevant engineering data. A single
product typically contains data collected over one Earth day. A description of each product type is
given in the table below. Code refers to the product type abbreviation used in the file name.


Code     Product Type        Description                                             Storage Format

CTS      Counter             This product type contains counting rate data along     Binary Table  
                             with associated timing, spatial, and engineering                      
                             data.                                                                 

ENG      Engineering         The engineering products contain selected data from     ASCII Table   
                             the NS raw status files converted to calibrated                       
                             physical units.                                                       

GAB      Gamma Burst         This product contains data from the raw gamma burst     ASCII Table   
                             product converted to ASCII. The spacecraft clocks                     
                             values have been converted to UTC.                                    

GCR      Galactic Cosmic     This product type contains spectra from the LG1 and     Binary Table  
         Ray Spectra         LG2 detectors when there was a coincidence condition                  
                             detected between both LG detectors and the BP                         
                             detector. The data have associated timing, spatial,                   
                             and engineering data.                                                 

SPE      Spectra             This product type contains calibrated neutron spectra   Binary Table  
                             from the three instrument detectors plus timing,                      
                             spatial, and engineering information taken during the                 
                             collection period. The spectra have been corrected                    
                             for gain variations, dead time and converted to                       
                             counts/sec.                                                           

NS Calibrated products have the following file names:
ns_cdr_zzzyyyydddwww.xxx
where:
zzz  = Product Type (Code)
yyyy = 4-digit year corresponding to the start time of the first record in the data table
ddd  = 3-digit day of year corresponding to the start time of the first record in the data table
www  = reserved 3-character string to use during the course of the mission as necessary to
       identify “special” data products; nominal data products will be identified with “ZZZ”
xxx  = File extension:
dat  = Binary data file
tab  = ASCII data file

The MESSENGER NS derived product collection consists of calibrated NS data that have been selected
to eliminate times where the background due to solar particle events is too high. Data have been
corrected for gain variations. In addition, products contain spacecraft navigation and attitude
data derived from SPICE files, as well as selected engineering data relevant to the NS. A single
product typically contains data collected over one Earth day. A description of each product type is
given in the table below. Code refers to the product type abbreviation used in the file name.


Code     Product Type        Description                                             Storage Format

NCR      Neutron Count       The product type contains net (background subtracted)   ASCII Table   
         Rate                neutron count rates from the LG1, LG2, and BP sensors                 
                             and uncertainties from each of these detectors.                       

NCP      Relative Neutron    These products contain latitude-binned fast and         ASCII Table   
         Count Rate          epithermal count rates, along with simulated count                    
                             rates for the cases with no hydrogen and with a thick                 
                             layer of 100 weight percent water ice in all radar                    
                             bright regions.                                                       

NS Derived NCR products have the following file names:
ns_ddr_zzzyyyydddwww.tab
where:
zzz  = Product Type (Code)
yyyy = 4-digit year corresponding to the start time of the first record in the data table
ddd  = 3-digit day of year corresponding to the start time of the first record in the data table
www  = reserved 3-character string to use during the course of the mission as necessary to
       identify “special” data products; nominal data products will be identified with “ZZZ”

This bundle was created and archived by the Geosciences Node of the Planetary Data System. 
Questions about this bundle may be directed to geosci@wunder.wustl.edu.