MAVEN Reconstructed SPK, NAV Solution, 2018-01-01 to 2018-04-01, Version 1 =========================================================================== Created by Boris Semenov, NAIF/JPL, Thu May 3 11:04:13 PDT 2018 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 6330 through 6811): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2018 JAN 01 00:01:09.183 2018 APR 01 01:01:09.185 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_06300-06334_rec_v1.bsp trj_orb_06333-06370_rec_v1.bsp trj_orb_06369-06409_rec_v1.bsp trj_orb_06408-06447_rec_v1.bsp trj_orb_06447-06489_rec_v1.bsp trj_orb_06488-06526_rec_v1.bsp trj_orb_06525-06564_rec_v1.bsp trj_orb_06563-06601_rec_v1.bsp trj_orb_06600-06639_rec_v1.bsp trj_orb_06638-06676_rec_v1.bsp trj_orb_06675-06714_rec_v1.bsp trj_orb_06713-06752_rec_v1.bsp trj_orb_06751-06789_rec_v1.bsp trj_orb_06788-06826_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_180101_180401_v1.bsp, km: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 6333 2018-01-01T17:03:50.816 -0.019 0.007 0.003 6339 2018-01-02T19:28:50.816 -0.001 0.001 -0.000 6346 2018-01-04T04:58:50.815 0.001 0.000 -0.001 6355 2018-01-05T18:40:50.815 0.007 -0.003 0.005 6364 2018-01-07T11:50:50.815 -0.015 0.007 -0.003 6369 2018-01-08T09:58:50.815 0.003 -0.001 0.001 6376 2018-01-09T16:59:02.815 0.008 -0.004 0.005 6380 2018-01-10T11:53:38.815 -0.026 0.009 -0.004 6386 2018-01-11T14:43:08.815 -0.004 0.001 -0.001 6392 2018-01-12T16:57:46.815 -0.010 0.005 -0.007 6400 2018-01-14T04:33:19.815 0.024 -0.011 0.019 6405 2018-01-15T04:33:14.815 0.007 -0.001 0.001 6408 2018-01-15T16:24:14.815 0.012 -0.006 0.010 6414 2018-01-16T21:20:50.815 0.004 0.000 -0.000 6421 2018-01-18T04:28:50.815 -0.037 -0.000 -0.003 6429 2018-01-19T16:28:50.815 -0.049 -0.003 -0.004 6437 2018-01-21T04:28:50.815 0.165 0.022 0.013 6447 2018-01-22T23:14:50.815 0.066 -0.029 0.059 6456 2018-01-24T16:58:50.815 -0.044 0.009 -0.025 6461 2018-01-25T16:16:50.815 -0.035 -0.008 -0.005 6470 2018-01-27T06:33:50.815 0.011 -0.006 0.013 6477 2018-01-28T16:05:50.815 -0.008 -0.002 -0.002 6478 2018-01-28T20:18:50.815 0.036 0.005 0.014 6480 2018-01-29T04:20:50.815 -0.008 0.002 -0.007 6488 2018-01-30T16:10:50.815 -0.010 0.003 -0.010 6498 2018-02-01T11:50:20.815 -0.004 0.002 -0.004 6509 2018-02-03T13:28:52.815 0.029 -0.015 0.040 6514 2018-02-04T11:31:25.815 0.015 -0.006 0.014 6519 2018-02-05T11:25:45.815 -0.039 0.006 -0.044 6525 2018-02-06T15:58:50.815 0.022 0.012 -0.006 6533 2018-02-08T04:11:20.815 -0.026 -0.013 0.027 6542 2018-02-09T17:58:50.815 0.033 -0.012 0.055 6551 2018-02-11T11:28:50.814 -0.012 -0.002 -0.013 6563 2018-02-13T16:58:50.814 -0.010 -0.001 -0.015 6573 2018-02-15T12:58:50.814 -0.003 0.000 -0.005 6584 2018-02-17T15:13:50.814 -0.003 -0.001 -0.005 6592 2018-02-19T04:03:50.814 -0.008 -0.004 -0.003 6600 2018-02-20T15:08:50.814 -0.018 -0.006 -0.035 6612 2018-02-22T21:38:50.814 -0.001 -0.000 -0.001 6622 2018-02-24T15:28:50.814 0.005 -0.002 0.012 6628 2018-02-25T18:23:50.814 -0.007 0.003 -0.019 6633 2018-02-26T19:13:50.814 -0.004 -0.002 -0.010 6638 2018-02-27T15:58:50.814 -0.000 0.000 -0.002 6644 2018-02-28T19:18:50.814 0.043 -0.003 0.204 6646 2018-03-01T03:49:50.814 -0.045 0.012 -0.228 6655 2018-03-02T20:00:34.814 -0.023 0.007 -0.134 6659 2018-03-03T15:08:39.814 0.053 0.015 0.316 6665 2018-03-04T16:00:49.814 -0.024 0.013 -0.124 6670 2018-03-05T14:43:17.814 0.018 -0.008 0.137 6675 2018-03-06T15:58:50.814 0.005 0.002 -0.009 6683 2018-03-08T03:38:50.814 0.001 0.000 0.002 6692 2018-03-09T19:03:50.814 -0.004 -0.002 -0.100 6698 2018-03-10T20:03:50.814 0.004 -0.001 0.163 6705 2018-03-12T03:32:50.814 0.000 0.000 -0.028 6713 2018-03-13T14:58:50.814 -0.003 0.001 0.045 6721 2018-03-15T03:43:50.814 -0.007 0.001 0.105 6730 2018-03-16T20:52:50.814 0.011 0.003 -0.122 6735 2018-03-17T17:53:50.814 0.020 -0.007 -0.148 6740 2018-03-18T15:48:50.814 -0.013 0.006 0.056 6751 2018-03-20T18:53:50.814 -0.019 -0.006 0.117 6759 2018-03-22T04:53:50.814 0.024 -0.011 -0.068 6767 2018-03-23T18:23:50.814 -0.011 -0.003 0.052 6772 2018-03-24T15:03:50.814 0.009 -0.005 -0.020 6780 2018-03-26T03:17:50.814 -0.008 0.002 0.023 6788 2018-03-27T14:39:13.814 -0.018 0.008 0.027 6794 2018-03-28T19:24:12.814 0.017 0.007 -0.056 6799 2018-03-29T16:02:42.814 -0.006 0.003 0.010 6805 2018-03-30T21:07:19.814 0.018 0.010 -0.050 End of comments.