Mars Reconnaissance Orbiter Extended Science Phase SPK, MRO NAV Solution =========================================================================== Created by Boris Semenov, NAIF/JPL, Mon May 3 13:13:32 PDT 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 67654 through 68809): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2021 JAN 01 00:01:10.000 2021 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_rec67686_67586_67686_r-v1.bsp spk_psp_rec67774_67683_67774_r-v1.bsp spk_psp_rec67863_67773_67863_r-v1.bsp spk_psp_rec67962_67861_67962_r-v1.bsp spk_psp_rec68050_67954_68050_r-v1.bsp spk_psp_rec68140_68048_68140_r-v1.bsp spk_psp_rec68230_68138_68230_r-v1.bsp spk_psp_rec68321_68228_68321_r-v1.bsp spk_psp_rec68411_68319_68411_r-v1.bsp spk_psp_rec68501_68408_68501_r-v1.bsp spk_psp_rec68576_68498_68576_r-v1.bsp spk_psp_rec68676_68570_68676_r-v1.bsp spk_psp_rec68770_68675_68770_r-v1.bsp spk_psp_rec68860_68769_68860_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_psp58.bsp, km: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 67671 2021-01-02T08:11:50.816 0.009 -0.000 -0.003 67683 2021-01-03T08:02:50.816 0.005 0.000 -0.001 67705 2021-01-04T23:57:50.815 0.021 -0.000 -0.003 67718 2021-01-05T23:57:50.815 -0.014 -0.000 0.006 67730 2021-01-06T22:26:50.815 0.007 -0.000 -0.003 67743 2021-01-07T22:56:50.815 -0.004 -0.000 0.001 67750 2021-01-08T12:54:50.815 -0.018 0.000 -0.004 67773 2021-01-10T08:12:50.815 0.015 -0.000 -0.003 67788 2021-01-11T11:55:50.815 -0.001 0.000 -0.000 67798 2021-01-12T05:25:50.815 -0.002 0.000 0.001 67814 2021-01-13T12:31:50.815 0.002 0.000 0.001 67827 2021-01-14T12:35:50.815 0.002 0.000 0.001 67846 2021-01-15T23:57:50.815 0.007 -0.000 0.003 67861 2021-01-17T04:41:50.815 0.012 -0.000 -0.002 67878 2021-01-18T12:35:50.815 -0.002 -0.000 0.001 67891 2021-01-19T12:19:50.815 0.001 0.000 0.000 67909 2021-01-20T22:04:50.815 0.022 0.000 0.005 67927 2021-01-22T07:40:50.815 -0.009 -0.000 -0.002 67949 2021-01-23T23:57:50.815 -0.005 -0.000 0.001 67954 2021-01-24T09:30:50.815 0.005 -0.000 0.001 67974 2021-01-25T23:57:50.815 0.002 0.000 -0.000 67993 2021-01-27T11:04:50.815 -0.001 -0.000 -0.000 68003 2021-01-28T05:39:50.815 0.015 0.000 0.004 68026 2021-01-29T23:57:50.815 -0.003 0.000 -0.000 68039 2021-01-30T23:57:50.815 0.010 0.000 -0.003 68048 2021-01-31T16:25:50.815 -0.024 -0.000 0.007 68064 2021-02-01T23:42:50.815 -0.010 -0.000 -0.002 68077 2021-02-02T23:54:50.815 -0.001 0.000 -0.000 68096 2021-02-04T11:30:50.815 0.008 0.000 0.002 68115 2021-02-05T23:00:50.815 -0.012 -0.000 -0.002 68129 2021-02-06T23:53:50.815 -0.005 -0.000 0.002 68138 2021-02-07T17:41:50.815 0.003 -0.000 0.001 68154 2021-02-08T23:48:50.815 -0.010 0.000 -0.002 68167 2021-02-09T23:48:50.814 0.006 -0.000 0.002 68180 2021-02-10T23:48:50.814 -0.010 0.000 -0.001 68193 2021-02-11T23:48:50.814 0.018 -0.000 -0.003 68206 2021-02-12T23:48:50.814 -0.009 -0.000 0.003 68218 2021-02-13T23:28:50.814 0.015 0.000 0.002 68228 2021-02-14T17:33:50.814 -0.013 0.000 -0.002 68257 2021-02-16T23:37:50.814 0.001 0.000 0.000 68270 2021-02-17T23:37:50.814 -0.001 -0.000 0.000 68283 2021-02-18T23:32:50.814 0.015 0.000 -0.004 68295 2021-02-19T23:21:50.814 -0.007 0.000 -0.001 68308 2021-02-20T23:32:50.814 0.005 -0.000 0.001 68319 2021-02-21T19:29:50.814 -0.015 0.000 -0.001 68334 2021-02-22T23:32:50.814 -0.011 0.000 -0.001 68351 2021-02-24T06:53:50.814 0.007 0.000 -0.002 68366 2021-02-25T10:57:50.814 -0.008 -0.000 0.002 68385 2021-02-26T23:27:50.814 -0.009 -0.000 -0.002 68398 2021-02-27T23:27:50.814 0.000 0.000 0.000 68408 2021-02-28T18:08:50.814 -0.003 0.000 -0.001 68424 2021-03-01T23:28:50.814 -0.013 -0.000 0.002 68437 2021-03-02T23:26:50.814 0.011 0.000 -0.003 68449 2021-03-03T23:09:50.814 0.001 0.000 0.000 68463 2021-03-04T23:57:50.814 0.003 0.000 -0.001 68475 2021-03-05T23:21:50.814 -0.005 0.000 -0.001 68488 2021-03-06T23:57:50.814 0.003 0.000 0.000 68498 2021-03-07T17:10:50.814 0.003 0.000 -0.000 68513 2021-03-08T22:45:50.814 -0.007 0.000 -0.001 68526 2021-03-09T23:03:50.814 0.014 -0.000 0.001 68539 2021-03-10T23:11:50.814 -0.015 0.000 -0.003 68552 2021-03-11T23:06:50.814 0.000 -0.000 0.000 68565 2021-03-12T23:16:50.814 -0.003 -0.000 -0.000 68570 2021-03-13T07:43:50.814 0.008 -0.000 -0.001 68591 2021-03-14T23:09:50.814 -0.012 -0.000 0.003 68603 2021-03-15T23:08:50.814 -0.002 -0.000 0.000 68620 2021-03-17T06:25:50.814 -0.001 -0.000 -0.000 68635 2021-03-18T10:15:50.814 -0.010 0.000 -0.002 68645 2021-03-19T05:28:50.814 0.013 0.000 0.001 68667 2021-03-20T22:34:50.814 0.017 0.000 0.001 68675 2021-03-21T11:57:50.814 0.007 -0.000 -0.001 68704 2021-03-23T19:22:50.814 0.000 0.000 0.000 68712 2021-03-24T10:00:50.814 0.016 -0.000 0.002 68731 2021-03-25T20:54:50.814 0.010 -0.000 -0.002 68744 2021-03-26T22:31:50.814 -0.003 0.000 -0.000 68758 2021-03-27T23:57:50.814 -0.026 0.000 -0.003 68769 2021-03-28T20:25:50.814 0.000 -0.000 0.000 68782 2021-03-29T21:14:50.814 0.013 -0.000 0.002 68796 2021-03-30T23:39:50.814 -0.005 -0.000 -0.000 68809 2021-03-31T22:49:50.814 -0.013 -0.000 0.002