PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1998-05-01 NOTE = "DATASET.TXT contains the data set description." END_OBJECT = TEXT END Data Set Summary ================ Data Set ID: VG1-J-SPICE-6-SPK-V2.0 Instrument: N/A Instrument P.I.: N/A Data Supplier: C. H. Acton Data sampling rate: N/A Data Set Start time: 1979-02-05T23:59:59.999Z Data Set Stop time: 1979-04-08T23:59:59.998Z Record format ------------- N/A Data column descriptions ------------------------ N/A Missing data flag value ----------------------- N/A Data Description ================ Version 2.0 ----------- This data set replaces the Voyager 1 Jupiter SPICE data set (DATA_SET_ID = VG1-J-6-SPK-V1.0). Data Set Description -------------------- This data set includes the spacecraft trajectory and allied planet and satellite ephemeris (SPK) kernel for the Voyager 1 Jupiter encounter, plus copies of the generic planetary constants (PCK) kernel, and the leap seconds (LSK) kernel. The SPK kernel provides ephemeris information for the period 1979-02-05 to 1979-04-08 for Voyager 1, Jupiter, Metis, Adrastea, Thebe, Amalthea, Callisto, Ganymede, Europa, Io, Earth, Moon, the Sun, and the Barycenters for all nine major planets. This file is provided in both PC binary (EBCDIC) and IEEE (Sun) binary format. The PCK kernel contains information specifying Jupiter's size, shape, and orientation. The LSK kernel is used for transforming between ephemeris time, the time system used in the SPK and PCK files, and UTC time (also referred to as Spacecraft Event Time or SCET). Both the PCK and LSK kernels are provided in ASCII format. The PCK kernel is PCK_version 00003 (1990-06-25). The LSK kernel includes leap seconds through 1991-01-01. Information regarding the SPK version and contents are detailed below. This data set is a NAIF SPK file, which is the realization of the SPICE S and P-ephemeris kernels. The SPICE S kernel is the logical component of the SPICE kernel concept which contains spacecraft trajectory data (position and velocity in a Cartesian reference frame). The SPICE P-ephemeris kernel is the logical component of the SPICE kernel concept which contains target (one or more of planet, satellite, comet, asteroid) ephemeris data (position and velocity in a Cartesian reference frame). NAIF provides a software toolkit, called SPICELIB, containing the Fortran 77 source code subroutines which a user needs to read SPK files. Those intending to use SPK kernel files should order this SPICELIB toolkit from the PDS (if it is not already on hand) and integrate appropriate modules into their own applications program. Users should NOT attempt to write their own software to read SPK kernels files. SPICELIB software is highly documented via internal headers, and some additional documentation is available in separate SPICELIB ASCII text files called Required Reading files. The SPK Required Reading File, identified as SPK.REQ, describes use of the SPK kernel readers. This particular data set is a merge of five SPK source files. Four of these (T790210, T790213, T790303, and T790318) were made from standard Voyager NAV Team archival products which were made for SEDR production. The fifth source file was (JUP024_VGR) made from a post-encounter satellite ephemeris file which contains ephemeris data for satellites which were not included in the standard Voyager NAV Team archival products. These source files are summarized below. NAIF_ID FOR EACH BODY INCLUDED NAV ID START TIME STOP TIME (See key below) -------------------------------------------------------------------- T790210 1979 FEB 06 00:00:00 1979 FEB 13 00:00:00 1 thru 10, 301, 399, 501 thru 505, 599, -31 T790213 1979 FEB 13 00:00:00 1979 FEB 19 00:00:00 1 thru 10, 301, 399, 501 thru 505, 599, -31 T790303 1979 FEB 19 00:00:00 1979 MAR 03 00:00:00 1 thru 10, 301, 399, 501 thru 505, 599, -31 T790318 1979 MAR 03 00:00:00 1979 APR 09 00:00:00 1 thru 10, 301, 399, 501 thru 505, 599, -31 JUP... 1979 FEB 01 00:00:00 1979 NOV 03 00:00:00 505, 514 thru 516, 024_VGR 599 NAIF body IDs are used within SPICE kernels to label data for a specific body. These IDs must be employed as arguments in the SPICELIB SPK kernel readers. Users might note that not all those bodies for which data are available in this file are listed in the Data Set Target Template below. Key to NAIF_IDs: 1 thru 9 are planet-satellite system barycenters for Mercury thru Pluto respectively. 199 thru 999 are planet mass centers for Mercury thru Pluto. 10 is the SUN. nxx are satellites, where n is the parent planet number. Thus, n=3 for Earth, n=4 for Mars, n=5 for Jupiter, etc. Satellites which may be found in this particular SPK file are: 501=IO, 502=EUROPA, 503=GANYMEDE, 504=CALLISTO, 505=AMALTHEA, 514=THEBE, 515=ADRASTEA, 516=METIS. Spacecraft are identified using the numeric IDs assigned by JPL's Deep Space Network (DSN), but with a minus sign preceding the number. Thus Voyager 1 is -31 and Voyager 2 is -32. Processing Level Id : 6 Software Flag : Y Processing Start Time : 1987-03-26 Processing Stop Time : 1989-08-29 Parameters ---------- N/A Source Instrument Parameters ---------------------------- N/A Measurement Information ----------------------- N/A Processing ---------- Processing History ------------------ Source Data Set ID : NAIF 18 Software : SPICELIB Product Data Set ID : VG1-J-6-SPK-V1.0 Source Data Set ID : NAIF 19 Software : SPICELIB Product Data Set ID : VG1-J-6-SPK-V1.0 Source Data Set ID : NAIF 20 Software : SPICELIB Product Data Set ID : VG1-J-6-SPK-V1.0 Source Data Set ID : NAIF 21 Software : SPICELIB Product Data Set ID : VG1-J-6-SPK-V1.0 Source Data Set ID : NAIF 121 Software : SPICELIB Product Data Set ID : VG1-J-6-SPK-V1.0 Software 'SPICELIB' ------------------- SPICELIB contains hundreds of ANSI FORTRAN 77 source code subroutines and functions for calculating instrument observation geometry. This software is intended to be integrated into a user's own science analysis application programs. Included in this library are readers for the SPICE kernels, which are the principal data sets used in computing instrument viewing geometry, or for planning data taking sequences. Additional software is available for then computing such items as latitude, longitude, phase angle, and emission angle of an instrument's principal point, or nearly any other geometric parameter of interest. Software Name : SPICELIB Software Type : NIN Software Release Date : 1990-02-05 Node ID : NAIF Cognizant Engineer : CHARLES H. ACTON Software Access Description : NOT ACCESSIBLE THROUGH PDS CATALOG - CONTACT PDS/NAIF NODE Note that this is not the official archive for these SPICE kernels. The PDS/NAIF node plans to officially archive these data on a separate volume. These data are provided here for use with software designed to generate trajectory or perform coordinate transformations. To learn more about SPICE, or for information about how to acquire the official archive version of these kernels, or the SPICELIB software, please contact Charles H. Acton of the PDS/NAIF node (INTERNET: cacton@spice.jpl.nasa.gov, DECNET: NAIF::CACTON, PHONE: (818)354-3869 ) or check the PDS website's (http://pds.jpl.nasa.gov/) link to the NAIF node for current NAIF contact information. Confidence Level Overview ------------------------- There is essentially no loss in accuracy when an SPK file is made from one or several NAV source files. Statistics on ephemeris accuracy are not available, but errors are very small compared to normal uncertainties in reconstructed pointing knowledge for the Voyager science instruments.