Mars Reconnaissance Orbiter Extended Science Phase SPK, MRO NAV Solution =========================================================================== Created by Boris Semenov, NAIF/JPL, Wed May 6 12:21:47 PDT 2020 Objects in the Ephemeris -------------------------------------------------------- This SPK file contains ephemeris data for the Mars Reconnaissance Orbiter (MRO) spacecraft. The NAIF ID code for MRO is -74. Approximate Time Coverage -------------------------------------------------------- This file covers the following part of the Extended Science Phase of the MRO mission (orbits 62957 through 64123): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2020 JAN 01 00:01:10.000 2020 APR 01 01:01:09.185 Status -------------------------------------------------------- This file was created by merging regular reconstructed OD solution SPK files produced by the MRO NAV team during the Extended Science Phase of the mission. This file was created by NAIF for archiving in the Planetary Data System (PDS). Pedigree -------------------------------------------------------- The original SPK files used to create this file contained only reconstructed trajectory. They were officially delivered to the MRO project data base by the MRO NAV team. The list of the original files data from which has been merged into this file is provided in Appendix 1 of these comments. Segment Boundary Discontinuities -------------------------------------------------------- This SPK file contains a large number of 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 coverages immediately precede or follow it. The times and magnitudes of these discontinuities are provided in Appendix 2 of these comments. Usage -------------------------------------------------------- This file should be used together with DE414 planetary ephemeris and MAR063 satellite ephemeris since the original SPK files contained subsets of these particular ephemeris in them. Contacts -------------------------------------------------------- If you have questions regarding this data contact Boris V. Semenov (818)-354-8136 Boris.Semenov@jpl.nasa.gov Appendix 1: Original SPK List -------------------------------------------------------- The original SPK files, the data from which has been included into this file, are: spk_psp_rec63015_62927_63015_r-v1.bsp spk_psp_rec63109_63013_63109_r-v1.bsp spk_psp_rec63199_63107_63199_r-v1.bsp spk_psp_rec63289_63198_63289_r-v1.bsp spk_psp_rec63377_63288_63377_r-v1.bsp spk_psp_rec63468_63376_63468_r-v1.bsp spk_psp_rec63556_63466_63556_r-v1.bsp spk_psp_rec63662_63554_63662_r-v1.bsp spk_psp_rec63738_63660_63738_r-v1.bsp spk_psp_rec63828_63736_63828_r-v1.bsp spk_psp_rec63905_63826_63905_r-v1.bsp spk_psp_rec63992_63904_63992_r-v1.bsp spk_psp_rec64089_63990_64089_r-v1.bsp spk_psp_rec64186_64088_64186_r-v1.bsp Appendix 2: Segment Boundary Discontinuity Summary -------------------------------------------------------- This SPK file contains a large number of 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 5 columns. The first column is the orbit number within which a segment boundary with discontinuity occurs. The next column contains the UTC time of that segment boundary. The last three columns (3..5) 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 segment boundary discontinuities for this file are: # # Summary of discontinuities at segment boundaries for # SPK file ./mro_psp54.bsp, km: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 62965 2020-01-01T18:08:50.816 0.000 0.000 0.000 62981 2020-01-02T23:41:50.816 0.000 0.000 0.000 62991 2020-01-03T18:45:50.816 0.000 -0.000 0.000 63006 2020-01-04T22:49:50.815 0.000 0.000 0.000 63013 2020-01-05T10:55:50.815 -0.001 0.000 0.003 63025 2020-01-06T10:21:50.815 -0.001 0.000 -0.002 63042 2020-01-07T18:09:50.815 0.001 -0.000 0.001 63055 2020-01-08T18:28:50.815 0.000 -0.000 0.001 63069 2020-01-09T20:26:50.815 -0.001 -0.000 -0.002 63083 2020-01-10T22:49:50.815 -0.000 -0.000 -0.000 63095 2020-01-11T21:11:50.815 0.000 0.000 0.001 63107 2020-01-12T18:39:50.815 -0.001 -0.000 0.001 63120 2020-01-13T20:01:50.815 0.000 -0.000 0.000 63128 2020-01-14T10:26:50.815 -0.002 0.000 0.000 63146 2020-01-15T19:56:50.815 0.003 -0.000 -0.004 63172 2020-01-17T21:16:50.815 -0.001 0.000 -0.001 63186 2020-01-18T23:28:50.815 0.001 0.000 0.001 63198 2020-01-19T21:28:50.815 -0.001 -0.000 -0.001 63210 2020-01-20T20:03:50.815 -0.001 -0.000 -0.001 63229 2020-01-22T07:53:50.815 0.001 -0.000 0.001 63245 2020-01-23T13:48:50.815 0.002 -0.000 0.003 63263 2020-01-24T23:28:50.815 -0.002 -0.000 -0.004 63272 2020-01-25T16:18:50.815 -0.000 -0.000 -0.000 63288 2020-01-26T22:02:50.815 0.001 -0.000 0.002 63301 2020-01-27T22:32:50.815 0.001 -0.000 0.002 63312 2020-01-28T19:07:50.815 -0.001 0.000 -0.002 63325 2020-01-29T19:17:50.815 -0.001 -0.000 -0.002 63335 2020-01-30T14:07:50.815 0.002 -0.000 0.004 63352 2020-01-31T21:55:50.815 -0.001 0.000 -0.001 63365 2020-02-01T21:59:50.815 0.001 -0.000 0.001 63376 2020-02-02T17:45:50.815 0.000 0.000 -0.001 63401 2020-02-04T17:33:50.815 -0.001 0.000 -0.002 63414 2020-02-05T17:52:50.815 0.000 -0.000 0.000 63430 2020-02-06T23:48:50.815 -0.000 0.000 -0.000 63443 2020-02-07T23:57:50.815 -0.001 0.000 -0.001 63454 2020-02-08T20:41:50.815 0.001 0.000 0.002 63466 2020-02-09T18:08:50.815 -0.000 -0.000 0.000 63478 2020-02-10T17:34:50.814 0.000 -0.000 0.000 63492 2020-02-11T19:45:50.814 -0.000 0.000 -0.001 63503 2020-02-12T15:31:50.814 0.000 -0.000 -0.000 63530 2020-02-14T18:49:50.814 0.001 -0.000 0.001 63543 2020-02-15T19:08:50.814 -0.000 -0.000 -0.001 63554 2020-02-16T14:39:50.814 0.001 0.000 -0.002 63569 2020-02-17T19:45:50.814 0.000 -0.000 0.001 63584 2020-02-18T23:48:50.814 0.001 0.000 0.002 63597 2020-02-19T23:57:50.814 0.002 -0.000 0.003 63609 2020-02-20T22:34:50.814 -0.002 0.000 -0.003 63622 2020-02-21T22:53:50.814 0.000 0.000 0.001 63635 2020-02-22T23:15:50.814 0.000 -0.000 0.001 63649 2020-02-24T01:22:50.814 -0.001 0.000 -0.001 63660 2020-02-24T20:53:50.814 0.000 -0.000 -0.001 63675 2020-02-26T01:44:50.814 -0.000 -0.000 -0.000 63688 2020-02-27T02:18:50.814 0.001 -0.000 0.002 63705 2020-02-28T10:06:50.814 0.000 0.000 0.001 63724 2020-02-29T21:38:50.814 -0.000 0.000 -0.001 63736 2020-03-01T19:05:50.814 0.001 0.000 -0.002 63751 2020-03-02T23:50:50.814 0.000 -0.000 0.000 63772 2020-03-04T15:18:50.814 0.000 0.000 0.000 63789 2020-03-05T23:11:50.814 -0.001 -0.000 -0.003 63803 2020-03-07T01:07:50.814 0.000 -0.000 0.001 63814 2020-03-07T21:20:50.814 0.001 -0.000 -0.000 63826 2020-03-08T20:14:50.814 0.000 0.000 -0.000 63841 2020-03-09T23:55:50.814 0.000 0.000 0.000 63852 2020-03-10T21:01:50.814 -0.000 -0.000 -0.000 63864 2020-03-11T18:35:50.814 -0.000 0.000 0.001 63872 2020-03-12T10:25:50.814 0.001 -0.000 0.002 63891 2020-03-13T21:57:50.814 0.000 0.000 0.000 63904 2020-03-14T21:08:50.814 -0.000 0.000 0.001 63926 2020-03-16T14:33:50.814 -0.000 0.000 0.000 63943 2020-03-17T23:12:50.814 -0.000 -0.000 -0.000 63962 2020-03-19T10:43:50.814 -0.000 -0.000 -0.000 63981 2020-03-20T22:16:50.814 0.000 0.000 0.001 63990 2020-03-21T14:03:50.814 -0.000 -0.000 0.000 64009 2020-03-23T02:31:50.814 -0.000 -0.000 -0.000 64026 2020-03-24T10:25:50.814 0.000 -0.000 0.001 64039 2020-03-25T10:44:50.814 -0.000 0.000 -0.000 64052 2020-03-26T11:01:50.814 0.000 0.000 0.000 64072 2020-03-27T23:57:50.814 0.000 -0.000 -0.000 64088 2020-03-29T05:19:50.814 0.000 -0.000 -0.000 64103 2020-03-30T10:25:50.814 0.000 0.000 0.000 64118 2020-03-31T14:28:50.814 -0.001 -0.000 -0.002