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This description was generated automatically using input from the Planetary Data System. Overview ======== This data set contains the System III (1965.0) trajectory and Sun and Earth phase angles of Galileo and selected Jovian moons when Galileo was inside 30 Jupiter radii from Jupiter. Trajectories are sampled every 20 seconds. Coordinates =========== The Jupiter System III (1965) coordinate system follows the definition of Dr. Alex Dessler in Appendix B of 'Physics of the Jovian Magnetosphere' [DESSLER1983]. This coordinate system is the accepted standard for analysis of data from the jovian system. System III is a spherical, planetographic coordinate system where the planetary rotation rate of (9h, 55m, 29.71s) is based on the rate of rotation of Jupiter's magnetic field. The prime meridian is defined as the sub-Earth meridian at 00:00:00 UT on Jan 1, 1965. Range is measured from the Jupiter center of mass. Longitude for standard System III is measured west. This direction choice causes the coordinate system to be left-handed and to a stationary or distant observer, longitude increases with time. Also included are the Earth and Sun phase angles of each body at each sample time. Phase angles are the projection of the 3-body angle (Sun-Jupiter-body or Earth-Jupiter-body) into the Jovian equatorial plane. The angle is measured from the anti-Sunward (or anti-Earthward) line, positive in the counterclockwise direction. Sun Phase Angle definition: Sun ^ | noon Jupiter Planetocentric 180 deg Equatorial Projection | | | | Jupiter * * */ * | * (dusk) 270 deg -----------*--|--*------------- 90 deg (dawn) * | * * * * | | | |-PA-- 0 deg body midnight Earth phase angle follows the same convention - simply replace the Sun in the diagram above with the Earth. Data Sampling ============= The data are sampled every 20 seconds inside of 30 Jupiter radii. Data Processing =============== The trajectory data were created using code written by Steven Joy to extract information from the SPICE (GO-J-SPICE-6-SPK-V1.0) products produced by the Galileo project. The software used to create this ephemeris is well tested and in agreement with similar software provided by the Galileo project. All of the SPICE kernels used to produce this data set are contained on the Io/J0 MWG archive volume CDROM in the GEOMETRY directory. Data ==== These data are derived from SPICE kernels produced by the Galileo NAV team during the mission. All of the SPICE kernels used to produce this data set are contained on the MWG archive volume DVD in the EXTRAS/SPICE/KERNELS directory. The kernels (PDS PRODUCT_ID) used to create this were: S980326B.TSP - Prime Mission Reconstruction (JA - E12) S000131A.TSP - GEM reconstruction (E12-E26) S030129A.TSP - GMM (I27-A34) reconstruction, J35 predict PCK00007.TPC - Planetary constants kernel (2000-04-24) MK00062B.TSC - Galileo spacecraft clock kernel All data are archived in ASCII tables (1 orbit/file). The data files for all orbits contain the following columns: -----------------------------------------------------------------------Column Type Description <units> -----------------------------------------------------------------------time char Sample time in PDS time format number GLL_R real Galileo range from Jupiter <Rj> (1 Rj = 71492 km) GLL_LAT real Galileo Jupiter planetocentric latitude <degrees> GLL_WLON real Galileo System III west longitude <degrees> GLL_SPHASE real Galileo Sun phase angle <degrees> GLL_EPHASE real Galileo Earth phase angle <degrees> IO_R real Io range from Jupiter <Rj> IO_LAT real Io Jupiter planetocentric latitude <degrees> IO_WLON real Io System III west longitude <degrees> IO_SPHASE real Io Sun phase angle <degrees> IO_EPHASE real Io Earth phase angle <degrees> EUR_R real Europa range from Jupiter <Rj> EUR_LAT real Europa Jupiter planetocentric latitude <degrees> EUR_WLON real Europa System III west longitude <degrees> EUR_SPHASE real Europa Sun phase angle <degrees> EUR_EPHASE real Europa Earth phase angle <degrees> GAN_R real Ganymede range from Jupiter <Rj> GAN_LAT real Ganymede Jupiter planetocentric latitude <degrees> GAN_WLON real Ganymede System III west longitude <degrees> GAN_SPHASE real Ganymede Sun phase angle <degrees> GAN_EPHASE real Ganymede Earth phase angle <degrees> CAL_R real Callisto range from Jupiter <Rj> CAL_LAT real Callisto Jupiter planetocentric latitude <degrees> CAL_WLON real Callisto System III west longitude <degrees> CAL_SPHASE real Callisto Sun phase angle <degrees> CAL_EPHASE real Callisto Earth phase angle <degrees> Due to their much lower periapsis, the data files for orbits A34 and J35 include ephemeris information for Amalthea (semimajor axis 2.5 Rj), and Thebe (semimajor axis 3.1 Rj). These files include the following additional columns: -----------------------------------------------------------------------Column Type Description <units> -----------------------------------------------------------------------AMA_R real Amalthea range from Jupiter <Rj> AMA_LAT real Amalthea Jupiter planetocentric latitude <degrees> AMA_WLON real Amalthea System III west longitude <degrees> AMA_SPHASE real Amalthea Sun phase angle <degrees> AMA_EPHASE real Amalthea Earth phase angle <degrees> THE_R real Thebe range from Jupiter <Rj> THE_LAT real Thebe Jupiter planetocentric latitude <degrees> THE_WLON real Thebe System III west longitude <degrees> THE_SPHASE real Thebe Sun phase angle <degrees> THE_EPHASE real Thebe Earth phase angle <degrees> Ancillary Data ============== SPICE kernels MK98264A.TLS (leapseconds), MK98264A.TLS (spacecraft clock), PK96030A.TPC (planetary constants), S980326B.TSP, S991130A.TSP, and S030129A.TSP (spacecraft/planetary ephemeris), and the rotor attitude file ROT_ATT.TAB located in the GEOMETRY directory of the GOMW_5001 volume can all be considered as ancillary data files for this data set. These are the files that were used to generate this data set. Ideally, these data should be generated on demand using the latest SPICE kernels available from the NAIF Node of the PDS. References ========== Russell, C.T., Geophysical coordinate transformations, Cosmic Electrodynamics, Reidel Publishing Co., Vol. 2, 174-196, 1971. Dessler, A. J., Appendix B Coordinate Systems, in Physics of the Jovian Magnetosphere, (edited by A. J. Dessler), Cambridge Univ Press, 1983.

Alternate Names



  • Planetary Science: Fields and Particles

Additional Information


Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II



NameRoleOriginal AffiliationE-mail
Mr. Steven P. JoyData ProviderUniversity of California, Los
Mr. Steven P. JoyGeneral ContactUniversity of California, Los
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