2001 Mars Odyssey Mapping SPK file, M01 NAV Solution =========================================================================== Created by Boris Semenov, NAIF/JPL, September 19, 2002 Objects in the Ephemeris -------------------------------------------------------- This file contains ephemeris data for 2001 Mars Odyssey (M01) spacecraft. NAIF ID code for M01 is -53. Approximate Time Coverage -------------------------------------------------------- This file covers the following part of the Mapping phase of the M01 mission: COVERAGE BEGIN TIME (TDB): 2002 FEB 19 00:00:00.000 COVERAGE END TIME (TDB): 2002 APR 01 01:00:00.000 Status -------------------------------------------------------- This file was created by merging regular reconstructed OD solution SPK files produced by M01 NAV during Mapping phase of the mission. The file was created by NAIF for archiving with the Planetary Data System (PDS). This file contains the same data as the "m01_map1.bsp" file released in June 2002, except it covers only through March 31, 2002. The reason for shortening the coverage of the originally released SPK was the request from the Mars 2001 Project Science Group (PSG) to align M01 SPICE kernel coverage boundaries with the archive cut-off boundaries for the Odyssey science data releases. Pedigree -------------------------------------------------------- The original SPK files used to create this file contained only reconstructed trajectory. They were officially delivered to the M01 project data base (FIS/DOM) by M01 NAV. The list of the original files data from which has been merged into this file is provided in the 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 coverage immediately precede and follow it. The times and magnitudes of these discontinuities are provided in the Appendix 2 of these comments. Usage -------------------------------------------------------- This file should be used together with DE405 planetary 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, bsemenov@spice.jpl.nasa.gov or M01 NAV Team Lead: Robert A. Mase (818)-354-8990 Robert.A.Mase@jpl.nasa.gov Appendix 1: Original SPK List -------------------------------------------------------- The original SPK files, the data from which has been included into this file, are: spk_m_od00808-00890_rec_v1.bsp spk_m_od00890-01015_rec_v1.bsp spk_m_od01015-01106_rec_v1.bsp spk_m_od01106-01190_rec_v1.bsp spk_m_od01190-01266_rec_v1.bsp spk_m_od01267-01360_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 m01_map1_v2.bsp: # #ORBNUM BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #------- ----------------------- ------- ------- ------- 827 2002-02-20T16:18:55.814 -0.008 -0.000 0.000 849 2002-02-22T10:28:55.814 0.002 0.000 0.001 868 2002-02-24T01:28:55.814 -0.017 -0.000 -0.005 889 2002-02-25T18:58:55.814 -0.000 -0.000 -0.000 914 2002-02-27T20:23:55.814 0.005 0.000 0.002 936 2002-03-01T15:43:55.814 -0.007 -0.000 -0.001 966 2002-03-04T02:58:55.814 -0.005 0.000 -0.001 993 2002-03-06T08:18:55.814 0.008 0.000 0.001 1014 2002-03-08T00:58:55.814 -0.010 -0.000 0.004 1037 2002-03-09T22:28:55.814 -0.005 -0.000 0.002 1059 2002-03-11T18:58:55.814 0.034 0.000 0.017 1084 2002-03-13T20:28:55.814 -0.017 -0.000 -0.009 1105 2002-03-15T13:38:55.814 -0.008 -0.000 -0.002 1129 2002-03-17T12:58:55.814 -0.012 0.000 -0.002 1153 2002-03-19T12:38:55.814 -0.016 -0.000 -0.007 1175 2002-03-21T07:48:55.814 0.002 0.000 0.000 1189 2002-03-22T11:33:55.814 0.005 -0.000 0.001 1211 2002-03-24T06:58:55.814 0.004 0.000 0.001 1229 2002-03-25T18:28:55.814 -0.016 -0.000 -0.001 1248 2002-03-27T07:03:55.814 0.012 -0.000 -0.002 1266 2002-03-28T18:23:55.814 0.000 -0.000 0.000