MAVEN Reconstructed SPK, NAV Solution, 2021-10-01 to 2022-01-01, Version 1 =========================================================================== Created by Boris Semenov, NAIF/JPL, Tue Feb 1 06:33:53 PST 2022 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 14887 through 15498): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2021 OCT 01 00:01:09.182 2022 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_14871-14999_rec_v1.bsp trj_orb_14998-15054_rec_v1.bsp trj_orb_15053-15099_rec_v1.bsp trj_orb_15098-15140_rec_v1.bsp trj_orb_15139-15193_rec_v1.bsp trj_orb_15192-15232_rec_v1.bsp trj_orb_15231-15291_rec_v1.bsp trj_orb_15290-15326_rec_v1.bsp trj_orb_15325-15371_rec_v1.bsp trj_orb_15370-15428_rec_v1.bsp trj_orb_15427-15471_rec_v1.bsp trj_orb_15470-15524_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_211001_220101_v1.bsp, km: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 14888 2021-10-01T07:53:50.817 -0.038 0.002 0.027 14905 2021-10-03T21:09:50.817 0.017 -0.002 -0.018 14924 2021-10-06T17:38:50.817 0.052 -0.004 -0.050 14949 2021-10-10T10:33:50.817 -0.074 0.020 -0.038 14962 2021-10-12T09:28:50.817 0.025 -0.005 0.010 14982 2021-10-15T11:08:50.817 0.065 0.008 -0.048 14998 2021-10-17T20:39:50.817 -0.059 0.000 0.043 15011 2021-10-19T18:49:50.817 0.113 -0.042 -0.002 15022 2021-10-21T10:08:50.817 -0.038 0.015 -0.022 15037 2021-10-23T16:58:50.817 -0.004 0.001 0.000 15053 2021-10-26T01:38:50.817 0.001 -0.001 0.002 15068 2021-10-28T07:40:50.817 0.019 -0.004 0.023 15077 2021-10-29T18:07:50.817 0.002 0.000 -0.002 15092 2021-10-31T22:53:50.817 -0.023 0.009 -0.022 15098 2021-11-01T20:24:50.817 0.009 -0.003 0.007 15111 2021-11-03T20:18:50.817 0.014 -0.000 -0.003 15123 2021-11-05T15:03:50.817 -0.012 0.004 -0.011 15139 2021-11-08T00:13:50.817 0.004 -0.002 0.010 15155 2021-11-10T10:58:50.817 -0.001 0.001 -0.002 15170 2021-11-12T16:58:50.817 -0.004 0.000 -0.004 15181 2021-11-14T07:53:50.817 -0.003 0.002 -0.012 15185 2021-11-15T00:23:50.817 0.009 0.003 -0.025 15192 2021-11-15T23:10:50.817 0.003 -0.001 0.011 15198 2021-11-16T20:46:50.817 0.003 -0.001 0.009 15211 2021-11-18T19:43:50.817 0.000 -0.000 0.002 15224 2021-11-20T19:43:50.817 0.001 -0.000 0.003 15231 2021-11-21T19:53:50.817 0.002 -0.001 0.010 15239 2021-11-23T01:33:50.817 -0.003 0.001 -0.021 15261 2021-11-26T08:07:50.817 0.002 -0.001 0.029 15271 2021-11-27T20:58:50.816 0.000 0.000 0.003 15284 2021-11-29T19:58:50.816 -0.001 0.000 0.034 15290 2021-11-30T16:48:50.816 -0.002 0.001 0.034 15305 2021-12-03T00:48:50.816 -0.001 -0.000 0.004 15315 2021-12-04T10:58:50.816 0.001 -0.000 -0.003 15325 2021-12-05T23:13:50.816 0.004 -0.001 -0.018 15338 2021-12-07T21:58:50.816 0.001 -0.000 -0.003 15345 2021-12-09T00:48:50.816 -0.009 -0.002 0.020 15359 2021-12-11T02:28:50.816 -0.001 0.000 0.003 15370 2021-12-12T17:24:50.816 -0.002 0.001 0.004 15377 2021-12-13T19:28:50.816 0.006 -0.001 -0.016 15396 2021-12-16T15:28:50.816 -0.005 0.002 0.010 15404 2021-12-17T21:13:50.816 -0.012 0.000 0.022 15412 2021-12-19T01:53:50.816 0.003 -0.000 -0.005 15424 2021-12-20T20:13:50.816 0.001 -0.000 -0.001 15427 2021-12-21T07:22:50.816 -0.006 0.002 0.008 15430 2021-12-21T18:58:50.816 0.008 -0.000 -0.012 15444 2021-12-23T21:10:50.816 0.015 -0.003 -0.021 15457 2021-12-25T19:18:50.816 -0.005 0.002 0.003 15464 2021-12-26T21:28:50.816 -0.017 0.001 0.019 15470 2021-12-27T18:58:50.816 -0.017 0.003 0.019 15477 2021-12-28T19:58:50.816 0.023 -0.006 -0.022 15484 2021-12-29T20:58:50.816 -0.017 0.006 0.012 15497 2021-12-31T20:01:50.816 0.006 -0.002 -0.005 End of comments.