Mars Reconnaissance Orbiter Extended Science Phase SPK, MRO NAV Solution =========================================================================== Created by Boris Semenov, NAIF/JPL, Thu Jan 28 07:27:49 PST 2021 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 66473 through 67653): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2020 OCT 01 00:01:10.000 2021 JAN 01 01:01:09.183 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_rec66523_66423_66523_r-v1.bsp spk_psp_rec66610_66521_66610_r-v1.bsp spk_psp_rec66700_66608_66700_r-v1.bsp spk_psp_rec66790_66698_66790_r-v1.bsp spk_psp_rec66879_66789_66879_r-v1.bsp spk_psp_rec66964_66878_66964_r-v1.bsp spk_psp_rec67055_66963_67055_r-v1.bsp spk_psp_rec67153_67053_67153_r-v1.bsp spk_psp_rec67243_67151_67243_r-v1.bsp spk_psp_rec67332_67239_67332_r-v1.bsp spk_psp_rec67422_67330_67422_r-v1.bsp spk_psp_rec67511_67421_67511_r-v1.bsp spk_psp_rec67589_67510_67589_r-v1.bsp spk_psp_rec67686_67586_67686_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_psp57.bsp, km: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 66482 2020-10-01T18:43:50.817 0.000 0.000 0.000 66497 2020-10-02T22:46:50.817 0.000 0.000 0.000 66510 2020-10-03T23:08:50.817 -0.000 0.000 -0.000 66521 2020-10-04T18:34:50.817 0.000 0.000 -0.000 66540 2020-10-06T07:09:50.817 -0.001 -0.000 -0.001 66557 2020-10-07T14:56:50.817 -0.001 0.000 -0.001 66569 2020-10-08T13:22:50.817 0.000 0.000 0.000 66584 2020-10-09T17:24:50.817 0.001 0.000 0.001 66594 2020-10-10T12:06:50.817 -0.000 0.000 -0.000 66608 2020-10-11T13:34:50.817 -0.000 0.000 0.000 66626 2020-10-12T23:55:50.817 -0.001 -0.000 -0.001 66636 2020-10-13T18:37:50.817 0.000 0.000 0.001 66645 2020-10-14T11:26:50.817 0.000 -0.000 0.000 66658 2020-10-15T11:44:50.817 0.002 -0.000 0.002 66671 2020-10-16T12:02:50.817 -0.003 0.000 -0.003 66690 2020-10-17T23:34:50.817 0.004 0.000 0.004 66698 2020-10-18T14:04:50.817 -0.001 -0.000 -0.000 66718 2020-10-20T03:07:50.817 -0.001 0.000 0.001 66735 2020-10-21T11:41:50.817 -0.000 0.000 0.000 66748 2020-10-22T11:59:50.817 0.002 -0.000 0.001 66765 2020-10-23T19:46:50.817 0.001 -0.000 0.001 66777 2020-10-24T17:42:50.817 -0.001 0.000 -0.000 66789 2020-10-25T15:29:50.817 -0.000 0.000 0.000 66801 2020-10-26T15:03:50.817 0.003 0.000 0.003 66814 2020-10-27T15:21:50.817 -0.005 0.000 -0.004 66824 2020-10-28T10:03:50.817 0.005 -0.000 0.004 66838 2020-10-29T11:32:50.817 -0.002 0.000 0.000 66855 2020-10-30T20:00:50.817 -0.001 0.000 -0.001 66870 2020-10-31T23:57:50.817 -0.002 -0.000 -0.001 66878 2020-11-01T13:49:50.817 0.002 -0.000 -0.001 66896 2020-11-02T23:57:50.817 0.002 0.000 -0.000 66909 2020-11-03T23:57:50.817 0.001 -0.000 -0.000 66919 2020-11-04T19:38:50.817 -0.003 0.000 -0.002 66935 2020-11-06T01:32:50.817 0.000 0.000 0.000 66950 2020-11-07T04:50:50.817 0.001 -0.000 -0.000 66963 2020-11-08T05:40:50.817 0.003 0.000 0.001 66978 2020-11-09T09:55:50.817 0.003 0.000 0.002 66991 2020-11-10T10:13:50.817 -0.000 -0.000 -0.000 67007 2020-11-11T15:40:50.817 -0.002 -0.000 -0.001 67016 2020-11-12T08:56:50.817 0.007 0.000 0.004 67037 2020-11-14T00:12:50.817 -0.003 -0.000 -0.002 67053 2020-11-15T05:25:50.817 -0.003 0.000 0.000 67071 2020-11-16T15:45:50.817 0.003 0.000 0.001 67082 2020-11-17T12:18:50.817 0.003 -0.000 0.002 67098 2020-11-18T18:13:50.817 -0.001 -0.000 -0.001 67114 2020-11-19T23:57:50.817 0.007 0.000 0.005 67127 2020-11-20T23:57:50.817 -0.004 0.000 -0.001 67139 2020-11-21T22:51:50.817 0.008 -0.000 0.004 67151 2020-11-22T20:20:50.817 0.000 -0.000 -0.000 67165 2020-11-23T23:27:50.817 -0.006 0.000 -0.003 67183 2020-11-25T09:06:50.817 -0.004 0.000 -0.002 67196 2020-11-26T09:24:50.817 0.003 0.000 0.001 67216 2020-11-27T22:44:50.816 -0.003 -0.000 -0.001 67230 2020-11-28T23:57:50.816 -0.004 0.000 0.002 67239 2020-11-29T18:19:50.816 0.004 -0.000 -0.002 67259 2020-12-01T06:58:50.816 -0.005 -0.000 -0.003 67273 2020-12-02T09:19:50.816 0.012 -0.000 0.005 67287 2020-12-03T11:29:50.816 0.008 0.000 0.004 67301 2020-12-04T13:39:50.816 -0.000 0.000 -0.000 67320 2020-12-05T23:57:50.816 -0.003 -0.000 0.002 67330 2020-12-06T19:01:50.816 -0.006 -0.000 0.002 67345 2020-12-07T23:54:50.816 -0.006 0.001 -0.002 67358 2020-12-09T00:08:50.816 -0.004 0.000 -0.002 67371 2020-12-09T23:57:50.816 -0.007 0.000 -0.002 67391 2020-12-11T12:49:50.816 0.007 0.000 -0.004 67409 2020-12-12T23:31:50.816 -0.001 0.000 -0.000 67421 2020-12-13T21:58:50.816 0.002 0.000 0.000 67436 2020-12-15T01:28:50.816 0.001 -0.000 -0.000 67461 2020-12-16T23:58:50.816 0.003 -0.000 -0.000 67474 2020-12-17T23:57:50.816 0.003 0.000 -0.001 67488 2020-12-19T03:02:50.816 -0.005 0.000 -0.002 67500 2020-12-20T01:12:50.816 0.000 0.000 0.000 67510 2020-12-20T19:27:50.816 -0.003 0.000 0.001 67525 2020-12-21T23:57:50.816 -0.002 -0.000 -0.001 67538 2020-12-22T23:46:50.816 -0.008 -0.000 0.002 67551 2020-12-23T23:57:50.816 -0.001 -0.000 0.000 67564 2020-12-24T23:57:50.816 0.002 0.000 -0.001 67576 2020-12-25T23:40:50.816 0.005 0.000 0.002 67586 2020-12-26T18:50:50.816 -0.011 -0.000 0.004 67608 2020-12-28T11:29:50.816 -0.002 -0.000 -0.001 67622 2020-12-29T13:27:50.816 -0.001 0.000 -0.000 67641 2020-12-30T23:57:50.816 0.011 0.000 -0.004 67653 2020-12-31T23:37:50.816 -0.013 0.000 -0.003