Data Set Information
DATA_SET_NAME VG1 JUP EPHEMERIS SYSTEM III (1965) COORDS BROWSE V1.1
DATA_SET_ID VG1-J-POS-6-SUMM-S3COORDS-V1.1
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview ================= Version 1.1 ----------- The SEDR based data provided as part of this data set were originally reviewed and archived with the NSSDC and PDS as version 1.0 (DATA_SET_ID = VG1-J-POS-4-48.0SEC). Version 1.1 includes additional columns not present in the previous version, 96 second rather than 48 second time samples, times converted to 'PDS Style' or ISO standard, and upgrading of PDS labels and templates to version 3.2. The SPICE based data that are also part of this data set were not previously archived with the PDS. This version 1.1 data set replaces previously archived versions. Data Set Description -------------------- This data set consists of Voyager 1 Jupiter encounter ephemeris data in System III (1965) left handed coordinates covering the period 1979-03-03 to 1979-03-16. Two versions, both covering the same time period, but containing slightly different data, are provided. One version was generated by the Voyager MAG team from Voyager 1 SEDR, the other by the PDS/PPI node using the VG1_JUP.BSP and PCK00003.TCP SPICE kernels. Two versions of the spacecraft ephemeris data are provided as an attempt to correct some of the problems in the Voyager SEDR while preserving the ability to reproduce early results. The original SEDR data has a variety of problems which may affect the knowledge of the spacecraft position, or conversely, the timing associated with certain events such as ring plane crossings. The SPICE SPK kernel provided on this disk includes corrections to some, but not all, of the problems associated with the Voyager SEDR. The Navigation and Ancillary Information Facility (NAIF) at JPL may issue a new Voyager SPK kernel in the future that will further improve the knowledge of the spacecraft location in inertial space. There are other differences in the in the two versions of ephemeris data that are the result of improvements in the knowledge of some of the physical constants associated with Jupiter and its moons. Since the Voyager era, there have been updates to the orientation of the jovian spin axis right ascension and declination, the radius of Jupiter, as well as the orbital characteristic and other physical parameters of many of the moons of Jupiter. These changes affect the stated position of the spacecraft in jovigraphic coordinate systems like System III without changing the position of the spacecraft in inertial space. The spin rate of Jupiter is not changed from the System III (1965) rate of 9h 55m 29.71sec (870.536 deg/day). The SPICE planetary constants kernel (PCK) contains both the current IAU definitions of the physical constants for the bodies within in the jovian system (as data) as well as the older IAU definitions (as comments). This is an ASCII text file (PCK00003.TCP) and users of the ephemeris data are encouraged to review it. SEDR generated ephemeris ------------------------ Instrument P.I. : N/A Data Supplier : NSSDC (Voyager MAG Team) Data sampling rate : 96 seconds Data Set Start Time : 1979-03-03T00:00:35.978Z Data Set Stop Time : 1979-03-16T23:59:08.185Z SPICE generated ephemeris ------------------------- Instrument P.I. : N/A Data Supplier : S. Joy Data sampling rate : 48 seconds Data Set Start Time : 1979-03-03T00:00:35.978Z Data Set Stop Time : 1979-03-16T23:59:56.185Z Parameters ========== SEDR generated ephemeris ------------------------ PARAMETER RESOLUTION/ DESCRIPTION NAME UNITS time 96.0 Sec time of the sample (UT) in the format yyyy-mm-ddThh:mm:ss.sssZ m65536 counts spacecraft clock counts mod60 counts fds_line counts sc_x R[J] jovicentric (System III) cartesian sc_y R[J] cartesian position vectors: X, Y, and sc_z R[J] Z vel_x km/s jovicentric X, Y, and Z spacecraft vel_y km/s velocity components vel_z km/s sc_r R[J] jovicentric (System III) spherical sc_lat degrees coordinates position vectors: range, sc_lon degrees latitude, and longitude CartSys3_to_SphSys3 cartesian system III to spherical system III coordinates rotation matrix containing 9 1pe15.8 elements SC_to_CartSys3 payload (spacecraft) to cartesian system III coordinates rotation matrix containing 9 1pe15.8 elements SC_to_SphSys3 payload (spacecraft) to spherical system III coordinates rotation matrix containing 9 1pe15.8 elements SPICE generated ephemeris ------------------------- PARAMETER RESOLUTION/ DESCRIPTION NAME UNITS time 48.0 Sec time of the sample (UT) in the format yyyy-mm-ddThh:mm:ss.sssZ R Rj jovicentric (System III 1965) LAT degrees spherical coordinates position LON degrees range, latitude, and longitude LocTime hours angular separation between the meridian containing the sun and the one containing the spacecraft converted to a time. The sun meridian is defined to be noon (12.000), with midnight (0.000) opposite it. Dawn (6.000) and dusk (18.000) are where the sun rises and sets according to the planet's rotation Coordinate System ================= The System III (1965) is a jovicentric left handed coordinate system defined such that longitude increases with time as viewed by a stationary remote observer. Jovicentric cartesian (Jupiter fixed) coordinates X points along the Jupiter-Sun line in the solar equatorial plane (positive towards the Sun) Y completes the right handed set Z points along the jovian spin axis, positive Jovicentric System III (1965) spherical coordinates R Jupiter to spacecraft range (positive away from Jupiter) LAT completes the left handed, orthogonal set LON System III (1965) east longitude (with longitude increasing eastward from a specific jovian prime meridian) SPICE ephemeris were generated using the current definition of the Jovian radius, 71492 km. The spin rate used in generating these data is the same as that used for System III (1965), +870.536 degrees/24 hours. Data Coverage ============= Filename Records Start Stop ------------------------------------------------------------------- SEDR062 1623 1979-03-03T00:00:35.978Z 1979-03-04T23:58:59.925Z SEDR064 6071 1979-03-05T00:00:35.925Z 1979-03-11T23:59:08.059Z SEDR071 4370 1979-03-12T00:00:44.059Z 1979-03-16T23:59:08.185Z SPICE062 3246 1979-03-03T00:00:35.978Z 1979-03-04T23:59:47.925Z SPICE064 12142 1979-03-05T00:00:35.925Z 1979-03-11T23:59:56.059Z SPICE071 8740 1979-03-12T00:00:44.059Z 1979-03-16T23:59:56.185Z
DATA_SET_RELEASE_DATE 1998-05-01T00:00:00.000Z
START_TIME 1979-03-03T12:00:35.978Z
STOP_TIME 1979-03-16T11:59:56.185Z
MISSION_NAME VOYAGER
MISSION_START_DATE 1972-07-01T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME JUPITER
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID VG1
INSTRUMENT_NAME N/A
INSTRUMENT_ID POS
INSTRUMENT_TYPE N/A
NODE_NAME planetary plasma interactions
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview ========================= SPICE generated ephemeris ------------------------- The SPICE generated data were derived from SPICE using software that has been extensively tested. They should give as accurate representation of spacecraft ephemeris as possible using these kernels. Comparisons between these data and other data from previous Jupiter missions should be performed with caution. Some key parameters, such as the Jovian radius, have changed from mission to mission. Definitions for Jupiter's spin rate and the orientation of its spin-axis have also changed slightly since the pre-Voyager days. Missing Data Flag ================= Any SEDR generated ephemeris data column whose value is -9.99999999e+10 is a missing data value.
CITATION_DESCRIPTION Acton, C.H., JR, Joy, S.P., VG1-J-POS-6-SUMM-S3COORDS-V1.1, VG1 JUP EPHEMERIS SYSTEM III (1965) COORDS BROWSE V1.1, NASA Planetary Data System, 1998.
ABSTRACT_TEXT This data set consists of Voyager 1 Jupiter encounter ephemeris data in System III (1965) left handed coordinates covering the period 1979-03-03 to 1979-03-16. Two versions, both covering the same time period, but containing slightly different data, are provided.
PRODUCER_FULL_NAME NATIONAL SPACE SCIENCE DATA CENTER
STEVEN P. JOY
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