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 : VG2-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 'Zulu time', and upgrading of PDS labels and templates to version 3.4. 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 2 Jupiter encounter ephemeris data in System III (1965) left handed coordinates covering the period 1979-07-05 to 1979-08-12. 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 2 SEDR, the other by the PDS/PPI node using the VG2_JUP.BSP and PCK00003.TCP SPICE kernels. Due to inaccuracies in Voyager SEDR, as well as changes in the values of some key parameters (e.g. Jovian radius) the timing is improved for the SPICE generated data. However, since much of the original analysis was based upon the SEDR generated ephemeris, this data has been included as well. SEDR generated ephemeris ------------------------ Instrument P.I. : N/A Data Supplier : NSSDC Data sampling rate : 96 seconds Data Set Start Time : 1979-07-05T00:00:47.269Z Data Set Stop Time : 1979-08-12T16:54:20.608Z SPICE generated ephemeris ------------------------- Instrument P.I. : N/A Data Supplier : S. Joy Data sampling rate : 48 seconds Data Set Start Time : 1979-07-05T00:00:47.269Z Data Set Stop Time : 1979-08-12T16:55:08.608Z 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 AU 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-------------------------------------------------------------------Volume ID: VG_1502 SEDR_S3_96S.TAB 31288 1979-07-05T00:00:47.269Z 1979-08-12T16:54:20.608ZSPICE_S3_48S.TAB 62578 1979-07-05T00:00:47.269Z 1979-08-12T16:55:08.608Z

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 early Pioneer days. Missing Data Flag : Any SEDR generated ephemeris data column whose value is -9.99999999e+10 is a missing data value.