Status of Voyager SPICE Kernels ============================================================================== Original Feb 14, 2012 C. Acton Update Jan 25, 2013 C. Acton ("new" post-1986 SPKs for VGR1 and VGR2) Update Jan 21, 2015 B. Semenov ("new" post-1986 SPKs for VGR1 and VGR2) Update Jun 16, 2021 M. Costa Sitja (updated best VGR2 Uranus FB data) Update Aug 21, 2022 B. Semenov (updated for SPKs extending to 2100) Update Aug 30, 2022 B. Semenov (updated vgr2_nep097.bsp) Overview ------------------------------------- The primary Voyager mission occurred in advance of the existence of SPICE. Assorted attempts have been made by a variety of people to "restore" some of the Voyager ancillary data into SPICE formats, with varying degrees of success. Use of *ANY* of the Voyager SPICE data provided here should be undertaken with extreme caution. SPKs -------------------------------------- The SPK information below was obtained from Robert Jacobson of JPL's Solar System Dynamics Group. Jacobson is the author of these trajectory solutions. The Voyager SPKs listed below are on the NAIF server here: https://naif.jpl.nasa.gov/pub/naif/VOYAGER/kernels/spk/ A summary of the contents and coverage of each of these SPKs, made using the SPICE Toolkit's "brief" utility, is provided in the spk folder in a text file named aa_summaries.txt. Additional meta-data for these files is provided below. Voyager 1 at Jupiter ~~~~~~~~~~~~~~~~~~~~ Current best is vgr1_jup230.bsp An update (improvement) is expected to be made, perhaps later in CY2012 Use Jupiter satellite ephemeris jup230-short.bsp found under generic_kernels/spk/satellites/a_older_versions to obtain the location of the Jupiter mass center (ID=599) or Jupiter's major satellites. Voyager 1 at Saturn ~~~~~~~~~~~~~~~~~~~ Current best is vgr1_sat337.bsp Further very small changes will be made during the life of the Cassini mission. Use satellite ephemeris sat351.bsp found under generic_kernels/spk/satellites to obtain the location of the Saturn mass center (699) or Saturn's major satellites. Voyager 2 at Jupiter ~~~~~~~~~~~~~~~~~~~~ Current best is vgr2_jup230.bsp An update (improvement) is expected to be made, perhaps later in CY2012. Use Jupiter satellite ephemeris jup230-short.bsp found under generic_kernels/spk/satellites/a_older_versions to obtain the location of the Jupiter mass center (ID=599) or Jupiter's major satellites. Voyager 2 at Saturn ~~~~~~~~~~~~~~~~~~~ Current best is vgr2_sat337.bsp Further very small changes will be made during the life of the Cassini mission. Use satellite ephemeris sat351.bsp found under generic_kernels/spk/satellites to obtain the location of the Saturn mass center (699) or Saturn's major satellites. Voyager 2 at Uranus ~~~~~~~~~~~~~~~~~~~ Current best is vgr2.ura111.bsp Use satellite ephemeris ura111.bsp found under generic_kernels/spk/satellites to obtain the location of the Uranus mass center (ID=799) or Uranus' major satellites. Voyager 2 at Neptune ~~~~~~~~~~~~~~~~~~~~ Current best is vgr2_nep097.bsp DE440 and NEP097 ephemerides were merged into this SPK for convenience. Previous best was vgr2_nep081.bsp No further updates are expected. Use satellite ephemeris nep081.bsp found under generic_kernels/spk/satellites to obtain the location of the Neptune mass center (ID=899) or Neptune's major satellites. Voyagers 1 and 2 for the periods after their last planetary flybys ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The following two files were made by merging the vg1_st and vg2_st files (found under a_older_versions) with run-outs of orbit solutions made using actual tracking data, but done after the supposedly "final" NAV team orbit solution delivered to the Voyager project. voyager_1.ST+1991_a54418u.merged.bsp voyager_2.ST+1992_m05208u.merged.bsp Slightly longer, covering up to 2030, run-out merged SPKs with the same supertrajectory data as the two SPKs above at the starts but inferior trajectories after 1986-Jan-1 (VGR1) and 1989-10-01 (VGR2) are: Voyager_1.a54206u_V0.2_merged.bsp Voyager_2.m05016u.merged.bsp These files are best to use for periods AFTER the files made for the last planetary flybys of each spacecraft: vgr1_sat337.bsp ending on 1980 OCT 06 vgr2_nep081.bsp ending on 1989 JUN 30 "generic_kernels" is found here: https://naif.jpl.nasa.gov/pub/naif/generic_kernels/ Voyagers 1 and 2 Extensions to 2100 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The Voyager 1 and 2 trajectories in the SPKs vgr1.x2100.bsp vgr2.x2100.bsp were provided by Robert Jacobson, JPL/SSD on August 19, 2022. They were generated by fitting data from the Saturn encounter through 1992 April for Voyager 1 and from the Neptune encounter through 1992 October for Voyager 2 and extending both trajectories to 2100 January. The JPL DE440 planetary ephemeris was used in these solutions and was merged into these SPKs by NAIF before releasing them the NAIF server. CKs -------------------------------------------- Two kinds of CKs are present in the CK folder. All such CKs come with substantial caveats and should be used only with great caution. CK files with namestyle "vgx_super" provide orientation of the spacecraft bus relative to the ECLIPB1950 reference frame, and are made from so-called "fixed instrument Supplemental Experiment Data Record" files provided by GSFC. Both binary (*.bc) for Unix/Linux/Intel Mac and SPICE transfer format (*.xbc) are provided. Each has substantial, important meta-data included inside the comment area, and also provided as *.cmt files; any prospective user MUST carefully read these comments. CK files having namestyle vgx_***_qmw_** provide pointing for either the wide angle (wa) or narrow angle (na) camera taken from portions of the Voyager camera system Supplemental Experiment Data Record (SEDR) files, for both Jupiter (jup) and Saturn (sat) flybys. These CKs were produced by Mitch Gordan of Queen Mary and Westfield College. You should download any binary CK using binary mode of FTP. If working on a Windows-based machine you should download the SPICE transfer format version of the file using ASCII mode of FTP, and then convert it to binary mode on your machine using either the "toxfr" or the "spacit" utility program available in each SPICE Toolkit. The PDS Rings Node, SETI Institute, has produced some new Voyager CKs. Check here for details: http://pds-rings.seti.org/voyager/spice/ck.html (Note: NAIF is not doing any work on Voyager CKs.) SCLKs ------------------------------------------- Voyager SCLKs are on the NAIF server here: https://naif.jpl.nasa.gov/pub/naif/VOYAGER/kernels/sclk/ Updates are placed there as new clock correlation data become available from the project. These latest versions are suitable for working with SCLK times from any time during the mission prior to the SCLK product creation time (displayed in the file header). They may also be used for future times up until the date the next update is produced. End of readme file.