MAVEN Reconstructed SPK, NAV Solution, 2021-01-01 to 2021-04-01, Version 1 =========================================================================== Created by Boris Semenov, NAIF/JPL, Mon May 3 13:04:46 PDT 2021 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 13070 through 13668): Start of Interval (ET) End of Interval (ET) -------------------------------- -------------------------------- 2021 JAN 01 00:01:09.183 2021 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_13055-13085_rec_v1.bsp trj_orb_13084-13165_rec_v1.bsp trj_orb_13164-13194_rec_v1.bsp trj_orb_13193-13231_rec_v1.bsp trj_orb_13230-13282_rec_v1.bsp trj_orb_13281-13328_rec_v1.bsp trj_orb_13327-13382_rec_v1.bsp trj_orb_13381-13418_rec_v1.bsp trj_orb_13417-13474_rec_v1.bsp trj_orb_13473-13521_rec_v1.bsp trj_orb_13520-13561_rec_v1.bsp trj_orb_13560-13614_rec_v1.bsp trj_orb_13613-13661_rec_v1.bsp trj_orb_13660-13707_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_210101_210401_v1.bsp, km: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 13075 2021-01-01T19:28:50.816 -0.002 0.000 0.001 13084 2021-01-03T03:58:50.816 0.006 -0.002 -0.005 13095 2021-01-04T19:00:46.815 -0.006 0.002 0.005 13101 2021-01-05T19:05:50.815 -0.000 -0.000 -0.000 13110 2021-01-07T01:46:28.815 0.018 -0.005 -0.012 13114 2021-01-07T17:56:50.815 -0.013 -0.005 -0.006 13123 2021-01-09T00:43:50.815 0.004 -0.001 -0.002 13130 2021-01-10T01:58:50.815 -0.007 0.002 0.004 13137 2021-01-11T02:28:50.815 0.001 -0.000 -0.000 13152 2021-01-13T09:23:50.815 -0.008 0.002 0.004 13164 2021-01-15T05:56:50.815 -0.033 -0.011 0.001 13170 2021-01-16T01:30:50.815 -0.004 0.002 0.001 13176 2021-01-17T00:13:50.815 0.007 -0.001 -0.003 13183 2021-01-18T00:50:50.815 0.007 -0.003 -0.003 13193 2021-01-19T13:37:10.815 0.003 -0.000 -0.001 13203 2021-01-21T01:56:50.815 -0.019 0.001 0.005 13208 2021-01-21T19:14:59.815 0.019 -0.007 -0.006 13216 2021-01-22T23:58:50.815 -0.013 0.004 0.003 13230 2021-01-25T02:06:50.815 0.002 -0.001 -0.000 13242 2021-01-26T21:09:50.815 0.001 -0.000 -0.000 13254 2021-01-28T18:08:50.815 -0.002 -0.000 0.000 13268 2021-01-30T19:13:50.815 0.008 -0.002 -0.000 13281 2021-02-01T17:58:50.815 0.004 0.000 -0.000 13288 2021-02-02T19:28:50.815 0.003 -0.001 -0.000 13296 2021-02-04T02:18:50.815 -0.001 -0.001 -0.000 13308 2021-02-05T20:11:35.815 0.008 -0.004 0.000 13314 2021-02-06T17:20:52.815 -0.004 0.002 0.000 13321 2021-02-07T18:36:50.815 -0.006 0.002 0.000 13327 2021-02-08T18:33:41.815 -0.022 -0.008 -0.002 13334 2021-02-09T18:28:50.814 0.014 -0.002 0.002 13343 2021-02-11T02:58:50.814 -0.022 0.004 -0.004 13354 2021-02-12T17:48:50.814 0.011 -0.004 0.000 13367 2021-02-14T17:18:50.814 -0.002 0.001 -0.000 13374 2021-02-15T18:38:50.814 -0.020 0.005 -0.005 13381 2021-02-16T18:58:50.814 -0.018 0.005 0.003 13395 2021-02-18T21:33:50.814 0.012 -0.004 -0.002 13401 2021-02-19T19:13:50.814 -0.009 0.003 0.002 13409 2021-02-21T00:28:50.814 0.012 -0.005 0.002 13417 2021-02-22T06:48:50.814 -0.008 -0.002 -0.004 13427 2021-02-23T17:12:17.814 0.019 -0.008 -0.002 13436 2021-02-25T01:39:22.814 -0.018 0.007 0.003 13440 2021-02-25T17:20:08.814 0.005 -0.000 0.003 13447 2021-02-26T17:58:50.814 0.020 -0.007 0.008 13467 2021-03-01T17:58:50.814 -0.021 0.007 -0.006 13473 2021-03-02T15:28:50.814 -0.002 0.001 -0.000 13487 2021-03-04T17:48:50.814 0.011 -0.004 -0.002 13499 2021-03-06T14:38:50.814 -0.006 -0.001 -0.006 13507 2021-03-07T17:53:50.814 -0.000 0.000 0.000 13514 2021-03-08T19:51:50.814 0.007 -0.002 0.004 13520 2021-03-09T16:48:50.814 0.006 -0.002 -0.003 13527 2021-03-10T18:51:05.814 0.009 -0.002 0.006 13533 2021-03-11T16:25:50.814 -0.013 0.004 -0.009 13540 2021-03-12T17:46:16.814 0.026 -0.006 0.019 13546 2021-03-13T15:18:50.814 -0.022 0.006 -0.013 13555 2021-03-15T00:08:50.814 -0.005 0.001 -0.006 13560 2021-03-15T17:58:50.814 0.001 -0.000 0.001 13568 2021-03-16T22:28:50.814 -0.000 -0.000 0.000 13580 2021-03-18T18:03:50.814 -0.008 0.002 -0.006 13593 2021-03-20T17:08:50.814 0.003 -0.001 0.004 13602 2021-03-22T01:23:50.814 0.015 -0.004 0.011 13607 2021-03-22T19:43:50.814 -0.025 0.003 -0.032 13613 2021-03-23T17:08:50.814 -0.012 0.003 -0.011 13620 2021-03-24T18:26:50.814 0.002 -0.000 0.002 13633 2021-03-26T17:38:50.814 -0.006 0.000 -0.010 13639 2021-03-27T15:58:50.814 0.003 0.001 0.009 13649 2021-03-29T03:38:50.814 -0.000 0.000 -0.000 13660 2021-03-30T18:58:31.814 -0.002 0.000 -0.004 13666 2021-03-31T17:33:26.814 0.002 0.001 0.009 End of comments.