• 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 s Time Samples rather than 48 s 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 from 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 Magnetometer (MAG) Team from the 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., the Radius of Jupiter) the Timing is improved for the SPICE generated Data. However, since much of the original Analysis was based upon the SEDR generated Ephemeris, these Data have been included as well.

• SEDR Generated Ephemeris
• ========================

+------------------------------------------------------+
| Parameter Characteristics | Value |

| 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
• =========================

+------------------------------------------------------+
| Parameter Characteristics | Value |

| 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 Name | Resolution/Units | Description |

| time | 96 s | Time of the Sample (UT) in the Format YYYY-MM-DDTHH:MM:SS.SSSZ |
| m65536 | counts | Spacecraft Clock Counts, mod 65536 |
| mod60 | counts | Spacecraft Clock Counts, mod 60 |
| fds_line | counts | Spacecraft Clock Counts, fds_line |
| sc_x | R[J] | Jovicentric (System III) Spacecraft Position, Cartesian Coordinates, X Component |
| sc_y | R[J] | Jovicentric (System III) Spacecraft Position, Cartesian Coordinates, Y Component |
| sc_z | R[J] | Jovicentric (System III) Spacecraft Position, Cartesian Coordinates, Z Component |
| vel_x | km/s | Jovicentric (System III) Spacecraft Velocity, Cartesian Coordinates, X Component |
| vel_y | km/s | Jovicentric (System III) Spacecraft Velocity, Cartesian Coordinates, Y Component |
| vel_z | km/s | Jovicentric (System III) Spacecraft Velocity, Cartesian Coordinates, Z Component |
| sc_r | AU | Jovicentric (System III) Spacecraft Position, Spherical Coordinates, Radial Distance (Range) |
| sc_lat | degrees | Jovicentric (System III) Spacecraft Position, Spherical Coordinates, Latitude |
| sc_lon | degrees | Jovicentric (System III) Spacecraft Position, Spherical Coordinates, Longitude |
| CartSys3_to_SphSys3 | | Cartesian System III to Spherical System III Coordinates Rotation Matrix containing nine 1PE15.8 Elements |
| SC_to_CartSys3 | | Payload (Spacecraft) to Cartesian System III Coordinates Rotation Matrix containing nine 1PE15.8 Elements |
| SC_to_SphSys3 | | Payload (Spacecraft) to Spherical System III Coordinates Rotation Matrix containing nine 1PE15.8 Elements |
+----------------------------------------------------------------------------------------------------------------------------------------------------+

• SPICE Generated Ephemeris
• =========================

+-----------------------------------------------------------------------------------------------------------------------------------------------------+
| Parameter Name | Resolution/Units | Description |

| time | 48 s | Time of the Sample (UT) in the Format YYYY-MM-DDTHH:MM:SS.SSSZ |
| R | AU | Jovicentric (System III 1965) Spacecraft Position, Spherical Coordinates, Radial Distance (Range) |
| LAT | degrees | Jovicentric (System III 1965) Spacecraft Position, Spherical Coordinates, Latitude |
| LON | degrees | Jovicentric (System III 1965) Spacecraft Position, Spherical Coordinates, Longitude |
| LocTime | hours | Angular Separation between the Meridian containing the Sun and the one containing the Spacecraft converted |
| | | 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 Rotation of the Planet. |
+-----------------------------------------------------------------------------------------------------------------------------------------------------+

• 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 (Jupiter Fixed) Cartesian Coordinates
• =================================================

• X points along the Jupiter-Sun Line in the Solar Equatorial Plane, positive towards the Sun
• Y completes the right-handed Set, Y = X ⨯ Z
• Z points along the Spin Axis of Jupiter

• Jovicentric System III (1965) Spherical Coordinates
• ===================================================

• R gives the Jupiter to Spacecraft Range, positive away from Jupiter
• LAT completes the left-handed, Orthogonal Set
• LON gives the 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, 71,492 km. The Spin Rate used in generating these Data is the same as that used for System III (1965), 870.536° per Day.

• Data Coverage
• =============

+------------------------------------------------------------------------------------+
| Filename | Records | Start Date and Time | Stop Date and Time |

| Volume ID: VG_1502 | | | |
| SEDR_S3_96S.TAB | 31288 | 1979-07-05T00:00:47.269Z | 1979-08-12T16:54:20.608Z |
| SPICE_S3_48S.TAB | 62578 | 1979-07-05T00:00:47.269Z | 1979-08-12T16:55:08.608Z |
+------------------------------------------------------------------------------------+