Galileo Spacecraft Trajectory SPK file, Robert Jacobson's 2021 Solution =========================================================================== Created by Marc Costa Sitja, NAIF/JPL, February 9, 2022. Objects in the Ephemeris -------------------------------------------------------- This file contains trajectory data for the Galileo spacecraft (NAIF ID -77) with respect to the Jupiter Barycenter (5) in the J2000 inertial reference frame. It also contains ephemerides of the Sun (10), planetary barycenters (1-9), Mercury (199), Venus (299), Earth (399), Moon (301), Mars (499), and Jupiter (599) and of a few Jovian satellites -- Io (501), Europa (502), Ganymede (503), Callisto (504), Amalthea (505), and Thebe (514). The planetary ephemerides included in this SPK are version DE440; the satellite ephemerides included in this file are versions JUP365 and MAR097. Approximate Time Coverage -------------------------------------------------------- The Galileo trajectory stored in this SPK file provides continuous coverage for the complete mission, specifically: Start of Interval (ET) End of Interval (ET) ----------------------------- ----------------------------- 1995 NOV 21 00:00:00.000 2002 NOV 26 08:00:00.000 Status -------------------------------------------------------- This file contains reconstructed Galileo trajectory determined by Robert A. Jacobson, Solar System Dynamics group, in 2021. It is intended for use in support of the Galileo experiment data processing and for archiving with the Planetary Data System (PDS). Pedigree -------------------------------------------------------- This file was created by Marc Costa Sitja using the trajectory solution provided in the form of a single SPK file by Robert A. Jacobson in January 2021. The SPK was provided along with a document internal to to JPL: R. A. Jacobson, ``The Reconstruction of the Galileo Tour'' Interoffice Memorandum 392R-21-002, 11 January 2021 This single SPK file was originated from a number of SPK files merged together using the SPKMERGE program by Robert A. Jacobson. The SPKMERGE log is provided in the Appendix 1 of these comments. The SPK file was merged then together by Marc Costa Sitja with DE440 planetary ephemerides and JUP365 and MAR097 satellite ephemerides using the SPKMERGE program. The SPKMERGE log is provided in the Appendix 2 of these comments. Segment Boundary Discontinuities -------------------------------------------------------- The original SPK file contains a large number of Galileo trajectory SPK segments that came from original individual SPK files. Although, each segment provides continuous trajectory within the interval that it covers, in general a position and velocity discontinuity exists at the boundary of the segment and the segments whose coverage immediately precede and follow it. The times and magnitudes of these discontinuities are provided in the Appendix 3 of these comments. Contacts -------------------------------------------------------- If you have questions regarding this data contact Marc Costa Sitja (818) 354-4852, Marc.Costa.Sitja@jpl.nasa.gov Appendix 1: SPKMERGE Log for the original SPK -------------------------------------------------------- The log from the SPKMERGE run that created this SPK is below. ; galileo.sc.bsp LOG FILE ; Created 2021-01-12/16:37:04.00. ; ; BEGIN SPKMERGE COMMANDS LEAPSECONDS_KERNEL = naif0012.tls SPK_KERNEL = galileo.sc.bsp SOURCE_SPK_KERNEL = pfile.Io.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1995 NOV 20 23:58:58.817 END_TIME = 1995 DEC 31 23:58:59.816 SOURCE_SPK_KERNEL = pfile.Ganymede0.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1995 DEC 31 23:58:59.816 END_TIME = 1996 JUN 12 11:58:58.815 SOURCE_SPK_KERNEL = pfile.Ganymede1.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1996 JUN 12 11:58:58.815 END_TIME = 1996 AUG 05 23:58:58.817 SOURCE_SPK_KERNEL = pfile.Ganymede2.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1996 AUG 05 23:58:58.817 END_TIME = 1996 SEP 10 23:58:58.818 SOURCE_SPK_KERNEL = pfile.Callisto3.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1996 SEP 10 23:58:58.818 END_TIME = 1996 DEC 15 23:58:58.817 SOURCE_SPK_KERNEL = pfile.Europa4.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1996 DEC 15 23:58:58.817 END_TIME = 1997 JAN 21 11:58:58.815 SOURCE_SPK_KERNEL = pfile.Europa6.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1997 JAN 21 11:58:58.815 END_TIME = 1997 MAR 14 23:58:58.814 SOURCE_SPK_KERNEL = pfile.Ganymede7.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1997 MAR 14 23:58:58.814 END_TIME = 1997 APR 21 23:58:58.814 SOURCE_SPK_KERNEL = pfile.Ganymede8.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1997 APR 21 23:58:58.814 END_TIME = 1997 JUN 03 23:58:58.815 SOURCE_SPK_KERNEL = pfile.Callisto9.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1997 JUN 03 23:58:58.815 END_TIME = 1997 AUG 18 11:58:57.817 SOURCE_SPK_KERNEL = pfile.Callisto10.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1997 AUG 18 11:58:57.817 END_TIME = 1997 OCT 15 23:58:57.818 SOURCE_SPK_KERNEL = pfile.Europa11.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1997 OCT 15 23:58:57.818 END_TIME = 1997 NOV 09 23:58:57.817 SOURCE_SPK_KERNEL = pfile.Europa12.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1997 NOV 09 23:58:57.817 END_TIME = 1998 JAN 17 11:58:57.816 SOURCE_SPK_KERNEL = pfile.Europa13.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1998 JAN 17 11:58:57.816 END_TIME = 1998 MAR 14 00:58:57.814 SOURCE_SPK_KERNEL = pfile.Europa14.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1998 MAR 14 00:58:57.814 END_TIME = 1998 JUN 27 00:58:57.816 SOURCE_SPK_KERNEL = pfile.Europa16.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1998 JUN 27 00:58:57.816 END_TIME = 1998 AUG 10 09:58:57.817 SOURCE_SPK_KERNEL = pfile.Europa17.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1998 AUG 10 09:58:57.817 END_TIME = 1998 DEC 31 23:58:57.816 SOURCE_SPK_KERNEL = pfile.Europa19.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1998 DEC 31 23:58:57.816 END_TIME = 1999 APR 10 23:58:56.814 SOURCE_SPK_KERNEL = pfile.Callisto20.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1999 APR 10 23:58:56.814 END_TIME = 1999 JUN 04 23:58:56.815 SOURCE_SPK_KERNEL = pfile.Callisto21.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1999 JUN 04 23:58:56.815 END_TIME = 1999 AUG 05 23:58:56.817 SOURCE_SPK_KERNEL = pfile.Callisto22.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1999 AUG 05 23:58:56.817 END_TIME = 1999 AUG 28 23:58:56.817 SOURCE_SPK_KERNEL = pfile.Callisto23.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1999 AUG 28 23:58:56.817 END_TIME = 1999 OCT 08 23:58:56.818 SOURCE_SPK_KERNEL = pfile.Io24.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1999 OCT 08 23:58:56.818 END_TIME = 1999 NOV 11 01:58:56.817 SOURCE_SPK_KERNEL = pfile.Io25.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1999 NOV 11 01:58:56.817 END_TIME = 1999 DEC 26 23:58:56.816 SOURCE_SPK_KERNEL = pfile.Europa26.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1999 DEC 26 23:58:56.816 END_TIME = 2000 FEB 06 05:58:56.815 SOURCE_SPK_KERNEL = pfile.Io27.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2000 FEB 06 05:58:56.815 END_TIME = 2000 APR 07 23:58:56.814 SOURCE_SPK_KERNEL = pfile.Ganymede28.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2000 APR 07 23:58:56.814 END_TIME = 2000 NOV 18 23:58:56.817 SOURCE_SPK_KERNEL = pfile.Ganymede29.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2000 NOV 18 23:58:56.817 END_TIME = 2001 APR 28 23:58:56.814 SOURCE_SPK_KERNEL = pfile.Callisto30.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2001 APR 28 23:58:56.814 END_TIME = 2001 JUL 16 23:58:56.816 SOURCE_SPK_KERNEL = pfile.Io31.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2001 JUL 16 23:58:56.816 END_TIME = 2001 AUG 27 23:58:56.817 SOURCE_SPK_KERNEL = pfile.Io32.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2001 AUG 27 23:58:56.817 END_TIME = 2001 DEC 01 11:58:56.817 SOURCE_SPK_KERNEL = pfile.Io33.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2001 DEC 01 11:58:56.817 END_TIME = 2002 JAN 31 23:58:56.815 SOURCE_SPK_KERNEL = pfile.Amalthea34.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 2002 JAN 31 23:58:56.815 END_TIME = 2002 NOV 26 07:58:55.817 ; END SPKMERGE COMMANDS Appendix 2: SPKMERGE Log -------------------------------------------------------- The log from the SPKMERGE run that created this SPK is below. ; gll_951120_021126_raj2021.bsp LOG FILE ; Created 2022-02-08/17:02:23.00. ; ; BEGIN SPKMERGE COMMANDS LEAPSECONDS_KERNEL = naif0012.tls SPK_KERNEL = gll_951120_021126_raj2021.bsp LOG_FILE = gll_951120_021126_raj2021.log SOURCE_SPK_KERNEL = galileo.sc.bsp INCLUDE_COMMENTS = NO BODIES = -77 BEGIN_TIME = 1995 NOV 20 23:58:58.817 END_TIME = 2002 NOV 26 07:58:55.817 SOURCE_SPK_KERNEL = jup365.bsp INCLUDE_COMMENTS = NO BODIES = 3, 5, 10, 399, 501, 502, 503, 504, 505, 514, 599 BEGIN_TIME = 1995 NOV 20 23:58:58.817 END_TIME = 2002 NOV 26 07:58:55.817 SOURCE_SPK_KERNEL = de440s.bsp INCLUDE_COMMENTS = NO BODIES = 1, 2, 4, 6, 7, 8, 9, 199, 299, 301 BEGIN_TIME = 1995 NOV 20 23:58:58.817 END_TIME = 2002 NOV 26 07:58:55.817 SOURCE_SPK_KERNEL = mar097.bsp INCLUDE_COMMENTS = NO BODIES = 499 BEGIN_TIME = 1995 NOV 20 23:58:58.817 END_TIME = 2002 NOV 26 07:58:55.817 ; END SPKMERGE COMMANDS Appendix 3: Segment Boundary Discontinuity Summary -------------------------------------------------------- This SPK file contains a large number of Galileo trajectory SPK segments that came from original individual SPK files. Although, each segment provides continuous trajectory within the interval that it covers, in general a position and velocity discontinuity exists at the boundary of the segment and the segments whose coverage immediately precede and follow it. The times and magnitudes of these discontinuities are provided in the table included in this Appendix. The top portion of the table contains the name of this SPK file. All descriptive lines in the top portion of the file start with the ``#'' character to allow direct plotting of the data in the freeware ``gnuplot'' application. The table consists of 4 columns. The first column contains the UTC time of that segment boundary. The last three columns (2..4) contain view coordinate frame components -- ``down track'' (this direction is parallel to the velocity vector), ``normal to plane'' (this direction is computed as cross product of position vector by velocity vector) and ``in plane'' (this direction is computed as a cross product of ``down track'' by ``normal to plane'') -- of the difference between the state vectors computed at that UTC time defining segment boundary at which a discontinuity exists. The pairs of segments and discontinuity times are determined using an algorithm that emulates the standard SPK loading priority -- ``last loaded segment takes precedence''. Therefore, the discontinuities summarized in the file are those which a user reading file would actually see. The difference components in the view coordinate frame were computed for each discontinuity using the following algorithm: -- A single state was computed from each pair of segment the J2000 frame at the time of discontinuity. -- For this pair of states, a position difference vector was computed by subtracting the state computed from the segment with higher priority from the state computed from segment with lower priority. Then, a frame transformation matrix rotating these difference vectors from J2000 to the view coordinate frame defined by the state obtained from the higher priority segment was computed, and the position difference vector was rotated to the view frame coordinates using this matrix. The Galileo trajectory segment boundary discontinuities for this file are: # # Summary of discontinuities at segment boundaries for # SPK file gll_951120_021126_raj2021.bsp: # # BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #----------------------- ----------- ----------- ----------- 1995-12-31T23:58:59.816 0.73777875 3.05855190 1.70016531 1996-06-12T11:58:58.815 0.49318365 -0.30425715 2.34315209 1996-08-05T23:58:58.816 0.20880007 0.25673874 2.34782592 1996-09-10T23:58:58.817 0.53910429 -0.45957421 4.81900349 1996-12-15T23:58:58.816 -0.45540739 0.18648817 0.69239848 1997-01-21T11:58:58.815 0.15598341 -0.08845606 -0.35510145 1997-03-14T23:58:58.814 0.03064078 0.04483393 0.35993303 1997-04-21T23:58:58.814 0.70259885 0.08486730 3.16198356 1997-06-03T23:58:58.815 0.25916332 0.08584065 -1.50849680 1997-08-18T11:58:57.817 -0.38957599 -0.39219369 0.25946116 1997-10-15T23:58:57.817 0.06000665 0.01338684 0.63462772 1997-11-09T23:58:57.817 -0.02012859 0.04095586 -4.26007811 1998-01-17T11:58:57.815 0.47138036 0.21924480 0.23766881 1998-03-14T00:58:57.814 3.13823188 1.14874343 4.77883004 1998-06-27T00:58:57.815 1.85987448 0.30707415 -0.89771972 1998-08-10T09:58:57.816 0.15886198 -0.15573049 1.70722887 1998-12-31T23:58:57.816 0.24856732 0.23045015 1.99873491 1999-04-10T23:58:56.814 1.08059712 1.16629482 0.46699413 1999-06-04T23:58:56.815 -0.01717521 -0.07515067 -1.99044351 1999-08-05T23:58:56.816 -0.18424028 -0.26042192 -1.64846542 1999-08-28T23:58:56.817 -0.07200383 -0.10931291 -2.58892428 1999-10-08T23:58:56.817 0.56124298 0.93289188 2.03218730 1999-11-11T01:58:56.817 -0.09542287 0.05278765 0.94665727 1999-12-26T23:58:56.816 0.09514248 0.07191734 -0.66437086 2000-02-06T05:58:56.815 0.53047673 0.01823408 -0.44762939 2000-04-07T23:58:56.814 0.23215130 -0.48853520 -2.51614097 2000-11-18T23:58:56.817 0.53999022 0.53280979 1.97455504 2001-04-28T23:58:56.814 0.22678806 -0.60829861 0.75780194 2001-07-16T23:58:56.816 -0.10276735 0.11372174 -0.24367506 2001-08-27T23:58:56.817 -0.12299208 0.18122583 -1.65177305 2001-12-01T11:58:56.816 0.11869450 0.29319630 -3.28587612 2002-01-31T23:58:56.815 0.10231004 -0.08704455 0.05562704 End of comments.