Mars Reconnaissance Orbiter Extended Science Phase SPK, MRO NAV Solution =========================================================================== Created by Boris Semenov, NAIF/JPL, Mon May 2 09:09:13 PDT 2011 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 20772 through 21926): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2011 JAN 01 00:01:06.183 2011 APR 01 01:01:06.185 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_rec21061_20975_21061_r-v1.bsp spk_psp_rec21299_21060_21299_r-v1.bsp spk_psp_rec21425_21297_21425_r-v1.bsp spk_psp_rec21514_21424_21514_r-v1.bsp spk_psp_rec21603_21513_21603_r-v1.bsp spk_psp_rec21690_21602_21690_r-v1.bsp spk_psp_rec21784_21689_21784_r-v1.bsp spk_psp_rec21874_21783_21874_r-v1.bsp spk_psp_rec21963_21873_21963_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_psp18.bsp: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 20779 2011-01-01T15:23:53.816 -0.001 -0.000 -0.001 20795 2011-01-02T20:00:53.816 0.002 -0.000 -0.001 20808 2011-01-03T21:39:53.815 -0.001 0.000 -0.001 20823 2011-01-05T01:40:53.815 0.003 0.000 0.001 20845 2011-01-06T19:09:53.815 -0.002 0.000 0.001 20864 2011-01-08T06:40:53.815 0.001 0.000 -0.000 20883 2011-01-09T16:34:53.815 -0.001 0.000 0.001 20903 2011-01-11T07:16:53.815 0.003 -0.000 0.002 20920 2011-01-12T15:06:53.815 -0.004 0.000 -0.001 20945 2011-01-14T13:49:53.815 0.004 -0.001 0.002 20963 2011-01-15T23:43:53.815 0.003 -0.000 -0.000 20975 2011-01-16T21:18:53.815 -0.002 0.000 -0.001 20998 2011-01-18T16:03:53.815 -0.000 -0.001 0.001 21016 2011-01-20T02:23:53.815 -0.001 0.000 -0.001 21036 2011-01-21T15:29:53.815 -0.001 0.000 -0.001 21060 2011-01-23T11:28:53.815 0.007 0.000 -0.004 21074 2011-01-24T14:28:53.815 0.007 0.000 0.002 21105 2011-01-27T00:33:53.815 0.003 0.000 0.001 21145 2011-01-30T03:08:53.815 -0.005 0.001 0.000 21179 2011-02-01T19:18:53.815 0.006 -0.000 0.003 21211 2011-02-04T07:08:53.815 -0.001 -0.001 -0.001 21245 2011-02-06T22:43:53.815 0.002 -0.001 -0.000 21271 2011-02-08T23:23:53.815 -0.002 -0.000 -0.002 21297 2011-02-10T22:48:53.814 -0.006 -0.001 0.002 21324 2011-02-13T02:43:53.814 0.002 -0.000 0.001 21344 2011-02-14T16:13:53.814 0.004 -0.002 0.000 21369 2011-02-16T14:43:53.814 0.001 -0.001 -0.001 21386 2011-02-17T22:27:53.814 0.005 0.000 0.004 21406 2011-02-19T11:52:53.814 0.001 -0.000 0.000 21424 2011-02-20T20:18:53.814 -0.001 0.000 0.001 21446 2011-02-22T14:38:53.814 -0.001 0.000 -0.001 21464 2011-02-24T00:18:53.814 -0.006 -0.000 -0.005 21485 2011-02-25T15:32:53.814 0.006 0.000 0.007 21500 2011-02-26T19:35:53.814 -0.002 -0.001 -0.003 21513 2011-02-27T18:45:53.814 0.001 -0.000 -0.002 21534 2011-03-01T11:31:53.814 0.002 -0.000 0.000 21554 2011-03-02T23:28:53.814 -0.000 0.000 -0.001 21567 2011-03-04T00:55:53.814 0.002 -0.001 0.001 21587 2011-03-05T14:26:53.814 -0.002 0.001 -0.001 21602 2011-03-06T17:13:53.814 0.001 0.000 -0.001 21624 2011-03-08T11:13:53.814 -0.002 0.000 -0.002 21643 2011-03-09T22:58:53.814 0.000 -0.000 -0.000 21659 2011-03-11T05:00:53.814 0.001 -0.001 -0.000 21677 2011-03-12T14:40:53.814 0.001 -0.001 -0.001 21689 2011-03-13T11:58:53.814 -0.001 -0.000 0.001 21709 2011-03-15T02:30:53.814 0.000 0.000 0.000 21729 2011-03-16T15:28:53.814 -0.001 -0.000 -0.000 21752 2011-03-18T10:32:53.814 0.002 -0.000 0.002 21772 2011-03-19T23:53:53.814 0.002 -0.000 0.001 21783 2011-03-20T19:43:53.814 0.002 0.000 -0.002 21804 2011-03-22T12:08:53.814 0.001 -0.000 0.002 21823 2011-03-23T23:48:53.814 0.001 -0.000 0.001 21842 2011-03-25T11:13:53.814 0.000 -0.000 0.000 21860 2011-03-26T20:53:53.814 0.000 0.000 0.000 21873 2011-03-27T20:03:53.814 -0.003 -0.000 0.005 21888 2011-03-29T01:33:53.814 -0.001 -0.000 -0.000 21909 2011-03-30T16:49:53.814 -0.000 0.000 -0.000 21924 2011-03-31T20:33:53.814 0.001 -0.000 0.002