PDS_VERSION_ID      = PDS3                                                    
RECORD_TYPE         = FIXED_LENGTH                                            
RECORD_BYTES        = 80                                                      
OBJECT              = TEXT                                                    
  PUBLICATION_DATE    = 2002-02-27                                            
  NOTE                = "Description of contents of CALIB directory "         
END_OBJECT          = TEXT                                                    
END                                                                           
                                                                              
                                                                              
                                                                              
      The CALIB directory contains leap second, planetary constants, clock    
conversion, and similar files.  The files are in ASCII format.                
                                                                              
     Some files evolved as the mission progressed (e.g., the leap second and  
clock conversion files); users should refer to the files on the most recent   
(highest numbered) archive volume for the most up-to-date information.        
                                                                              
     The files are:                                                           
                                                                              
CLOCK CONVERSION (SCK) FILES                                                  
                                                                              
     Clock conversion files allow time measured by the spacecraft clock to    
be converted to other time systems (e.g., ephemeris time or UTC).  These are  
ASCII files with variable length records delimited by ASCII carriage-return   
line-feed pairs.  File names are of the form  TSCnnnnn.SCK  where  nnnnn is   
a sequence number assigned by the generating entity.  Each file  TSCnnnnn.SCK 
is accompanied by a PDS detached minimal label with name  TSCnnnnn.LBL.       
                                                                              
LEAPSECOND KERNEL (LSK) FILES                                                 
                                                                              
     Leapsecond kernel files are a record of leap seconds (past and predicted)
that allow proper conversion between ephemeris time and UTC.  These are       
ASCII files with variable length records delimited by ASCII carriage-return   
line-feed pairs.  File names are of the form  LSKydddC.TLS  where  y  is the  
one-digit year of the file creation date;  ddd  is the three-digit day of year
of the file creation date; and  C  is a character, starting with "A", to      
distinguish among multiple files that have the same  ydddeee.  Each file      
LSKydddC.TLS  is accompanied by a PDS detached minimal label with name        
LSKydddC.LBL.                                                                 
                                                                              
PLANETARY CONSTANTS (PCK) FILES                                               
                                                                              
     Planetary Constants files contain dimensions, orientations, spin rates   
and other data about objects in the solar system.  These are ASCII files with 
variable length records delimited by ASCII carriage-return line-feed pairs.   
File names are of the form  PCKydddC.TPC  where  y  is the one-digit year of  
the file creation date;  ddd  is the three-digit day of year of the file      
creation date; and  C  is a character, starting with "A", to distinguish      
among multiple files that have the same  ydddeee.  Each file  PCKydddC.TPC    
is accompanied by a PDS detached minimal label with name  PCKydddC.LBL.