PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = TEXT PUBLICATION_DATE = 1998-06-30 NOTE = "CRS-80 File Format Description" END_OBJECT = TEXT END CRS-80 File Format Description 1. General Description ------------------- A CRS (Celestial Reference Set) file contains position and velocity vectors in Univac double precision, EME 50 spacecraft centered coordinates. CRS-80 is a binary format used for the Voyager encounters with Saturn (1980-81) and Uranus (1986). 2. Contents -------- Each CRS file contains one 378-byte header records, one 126-byte header record, an unlimited number of 378-byte data records, and an end-of-file record. 3. Volume ------ The size of the CRS file depends on the length of the trajectory processed, the frequency at which records are to be written, and the number of planets and satellites for which data is requested. The size of archival CRS files 4. Organization ------------ File 35 is written using onformatted FORTRAN. 5. Storage Medium -------------- File 35 is stored on FASTRAND. 6. Program Usage ------------- File 35 is written by subroutines CRSINI/CRS and CRSWRT/CRS of CRSPOST and it is read by several programs of the Guidance and Control Analysis Subsystem. 7. Detailed Description -------------------- The CRS save tape generated by CRSPOST of the DPTRAJ system contains trajectory data in the file format as follows: Word Num Name Dimension Type Value Definition ---- ------ --------- ---- ---------- -------------------------- 0 1 I Record label 1 NWRDSD 1 I 9+12*NBODL Number of words contained in the data array (record) 2-3 SP1950 1 DP Seconds (ET) past 0 hr 1 January 1950 4-5 JULDAT 1 DP Julian data (days) 6-7 GREDAT 2 I Gregorian calendar date (2 integer words which represent the vigesimal date) 8-9 ETMUTC 1 DP ET-UTC time difference 10 IRECFL 1 I Record flag and body indication = 0 TDT (time, delta time) event = K Planet or satellite = -K Planet or satellite apoapsis where K is a pointer to the location of the body in the KBODL list 11-(10+ POSSCB (6,NBODL) DP Words 1-3 are position 12*NBODL) vectors, KM, (EME50) spacecraft-centered. Words 4-6 are velocity vectors, KM/sec, (EME50) spacecraft centered. I/O read statement will be of the form READ (FILE) N, (IBUF (I), I = 1,N) where IBUD will be of type integer and of dimension of at least NWRDSD words. N will be equal to NWRDSD. d. Last Record (m + 3 record) This record will indicate end of data Word Num Name Dimension Type Value Definition ---- ------ --------- ---- ---------- -------------------------- 1 IEOF1 1 I 1 Number of words 2 IEOF3 1 O 3777777777777 The CRS save tape will have a software end-of-file mark. The DPTRAJ CRSPOST will have the capability to provide position and velocity vectors (EME50 coordinates and spacecraft centered) of the solar bodies listed in Table 1. Table 1 Valid Body Names for Use by CRSPOST MERCUR SATURN VENUS MIMAS EARTH ENCELA MOON TETHYS MARS DIONE PHOBOS RHEA DIEMOS TITAN JUPITE HYPERI IO IAPETU EUROPA PHOEBE GANYME JANUS CALLIS URANUS AMALTH ARIEL HIMALI UMBRIE ELARA TITANI PASIPH OBERON SINOPE MIRAND LYSITH NEPTUN CARME TRITON ANANKE NEREID LEDA PLUTO JXIV SUN