MAVEN Reconstructed SPK, NAV Solution, 2018-10-01 to 2019-01-01, Version 1 =========================================================================== Created by Boris Semenov, NAIF/JPL, Tue Feb 12 17:28:42 PST 2019 Objects in the Ephemeris -------------------------------------------------------- This SPK file contains ephemeris data for the Mars Atmosphere and Volatile Evolution Mission (MAVEN) spacecraft. The NAIF ID code for MAVEN is -202. Approximate Time Coverage -------------------------------------------------------- This file covers the following part of the orbital phase of the MAVEN mission (orbits 7804 through 8305): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2018 OCT 01 00:01:09.182 2019 JAN 01 01:01:09.183 Status -------------------------------------------------------- This file was created by merging regular reconstructed OD solution SPK files produced by the MAVEN NAV team during the orbital 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 MAVEN project data base by the MAVEN 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 DE430 planetary ephemeris and MAR097 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: trj_orb_07765-07808_rec_v1.bsp trj_orb_07807-07849_rec_v1.bsp trj_orb_07849-07889_rec_v1.bsp trj_orb_07888-07919_rec_v1.bsp trj_orb_07918-07966_rec_v1.bsp trj_orb_07965-08004_rec_v1.bsp trj_orb_08003-08039_rec_v1.bsp trj_orb_08038-08060_rec_v1.bsp trj_orb_08059-08110_rec_v1.bsp trj_orb_08109-08136_rec_v1.bsp trj_orb_08135-08195_rec_v1.bsp trj_orb_08194-08233_rec_v1.bsp trj_orb_08232-08265_rec_v2.bsp trj_orb_08264-08309_rec_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 ./maven_orb_rec_181001_190101_v1.bsp, km: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 7807 2018-10-01T19:38:50.817 0.004 0.002 -0.032 7811 2018-10-02T10:43:50.817 -0.005 0.003 0.107 7820 2018-10-04T02:23:50.817 0.001 -0.000 -0.081 7829 2018-10-05T18:25:16.817 0.000 -0.000 0.027 7836 2018-10-07T01:18:11.817 -0.000 0.000 -0.007 7842 2018-10-08T03:18:38.817 -0.001 0.000 -0.011 7849 2018-10-09T10:58:50.817 0.002 -0.001 0.026 7852 2018-10-10T00:53:50.817 -0.004 -0.000 -0.038 7864 2018-10-12T04:58:50.817 -0.000 0.000 -0.003 7874 2018-10-14T02:48:50.817 -0.004 -0.002 -0.011 7879 2018-10-15T01:13:50.817 0.013 0.007 0.005 7888 2018-10-16T16:28:50.817 0.019 0.009 0.044 7896 2018-10-18T01:58:50.817 -0.003 0.001 -0.013 7905 2018-10-19T17:28:50.817 -0.011 0.004 -0.040 7914 2018-10-21T09:06:50.817 0.017 -0.006 0.054 7918 2018-10-22T03:28:50.817 0.017 0.000 0.047 7929 2018-10-24T02:23:50.817 -0.021 0.011 -0.035 7934 2018-10-25T00:33:50.817 0.011 -0.006 0.023 7944 2018-10-26T20:23:50.817 -0.017 0.009 -0.023 7947 2018-10-27T11:58:50.817 0.049 0.020 0.082 7952 2018-10-28T09:58:50.817 -0.006 -0.002 -0.009 7956 2018-10-29T02:28:50.817 -0.019 0.002 -0.038 7965 2018-10-30T16:58:50.817 0.021 -0.011 0.030 7972 2018-11-01T00:43:50.817 -0.025 0.004 -0.043 7981 2018-11-02T17:23:50.817 0.014 0.005 0.021 7995 2018-11-05T07:23:50.817 -0.018 -0.009 -0.019 8003 2018-11-06T16:03:50.817 0.009 -0.004 0.007 8007 2018-11-07T09:28:50.817 0.006 -0.003 0.002 8019 2018-11-09T15:13:50.817 -0.012 0.003 -0.014 8023 2018-11-10T10:45:05.817 -0.012 -0.006 -0.008 8028 2018-11-11T08:25:08.817 -0.030 -0.013 -0.028 8032 2018-11-12T01:10:10.817 -0.041 -0.004 -0.043 8038 2018-11-13T03:15:50.817 0.081 -0.004 0.081 8049 2018-11-15T03:29:50.817 -0.055 0.007 -0.050 8059 2018-11-16T23:28:50.817 -0.009 0.001 -0.008 8065 2018-11-18T01:18:50.817 -0.012 0.005 -0.009 8070 2018-11-19T01:18:50.817 -0.010 -0.005 -0.007 8079 2018-11-20T17:08:50.817 -0.005 -0.003 -0.002 8088 2018-11-22T07:58:50.817 -0.004 -0.001 -0.003 8098 2018-11-24T01:58:50.817 0.002 -0.001 0.001 8109 2018-11-26T04:06:03.817 -0.009 -0.003 -0.005 8118 2018-11-27T17:54:03.817 -0.067 0.033 -0.022 8123 2018-11-28T15:31:05.816 0.047 -0.023 0.003 8129 2018-11-29T18:01:50.816 0.016 -0.008 0.003 8135 2018-11-30T21:43:50.816 0.007 -0.000 0.003 8142 2018-12-02T02:53:50.816 -0.028 0.012 0.002 8147 2018-12-03T02:58:02.816 0.087 0.015 0.035 8156 2018-12-04T17:07:15.816 0.033 -0.015 0.009 8167 2018-12-06T16:50:01.816 -0.012 0.005 0.000 8174 2018-12-08T00:28:50.816 -0.039 0.015 -0.011 8185 2018-12-10T00:28:50.816 -0.004 0.002 -0.001 8194 2018-12-11T17:18:50.816 0.075 0.001 0.018 8201 2018-12-13T00:58:50.816 -0.026 -0.011 -0.004 8214 2018-12-15T08:38:50.816 -0.030 0.008 -0.006 8219 2018-12-16T06:33:50.816 -0.004 0.001 -0.001 8224 2018-12-17T04:38:50.816 0.019 -0.005 0.004 8232 2018-12-18T15:48:50.816 -0.021 0.006 -0.004 8241 2018-12-20T06:18:50.816 0.006 -0.003 0.001 8250 2018-12-21T22:58:50.816 0.009 -0.003 0.002 8257 2018-12-23T06:47:50.816 -0.015 -0.003 -0.000 8264 2018-12-24T13:13:50.816 -0.017 -0.001 -0.001 8281 2018-12-27T16:38:50.816 0.019 0.007 -0.002 8289 2018-12-29T01:25:13.816 0.000 -0.000 0.000 8299 2018-12-31T00:22:37.816 -0.014 -0.007 0.005 End of comments.