PDS_VERSION_ID        = PDS3                                                  
RECORD_TYPE           = STREAM                                                
OBJECT                = TEXT                                                  
  PUBLICATION_DATE    = 2017-08-07                                            
  NOTE                = "Description of the DOCUMENT directory contents."     
END_OBJECT            = TEXT                                                  
END                                                                           
                                                                              
The DOCUMENT directory contains copies of documents that are necessary or     
useful for users to understand the archive data set. These documents are      
orgainized in the subdirectories listed below.                                
                                                                              
CERES_COORD_SYS                                                               
This document describes updates to the Ceres coordinate system made           
as a result of observation made by the NASA Dawn mission.                     
                                                                              
BGO_DATA_PROCESSING                                                           
This directory contains a document describing the GRaND BGO data processing   
for both Vesta and Ceres.                                                     
                                                                              
EPHEM_POINTING_GEOMETRY                                                       
This document provides an overview of the GRaND ephemeris, pointing and       
geometry (EPG) data. It describes the instrument timing and pointing and      
how those elements impact the data processing. This document applies to both  
 Vesta and Ceres observations.                                                
                                                                              
DATA_PROCESSING                                                               
PDS Data Processing document. This document describes data processing for the 
reduction of gamma ray and neutron spectroscopy data acquired by the NASA Dawn
mission's Gamma Ray and Neutron Detector (GRaND).                             
                                                                              
SCIENCE_PLAN                                                                  
The Dawn Science Plan document. This document provides a description of the   
planned Dawn observations at Ceres and as-flown observations through Vesta.   
It is provided as a source of information on the intent of the observations   
made by the instrument teams at Ceres. Note that not all of the planned       
observations actually occurred due to a variety of instrument resets and      
spacecraft safings.                                                           
                                                                              
SIS                                                                           
The Dawn Gamma Ray and Neutron Detector Software Interface Specification      
(SIS). This document describes the contents and types of archive volumes      
belonging to all of the GRaND NASA level 1 (CODMAC levels 2 and 3) data sets. 
This includes detailed descriptions of the data formats to allow users to read
the data products.