KPL/SCLK MSL SCLK File Implementing LMST at GC Landing Site =========================================================================== This file is a SPICE spacecraft clock (SCLK) kernel implementing Local Mean Solar Time (LMST). This file contains information required to convert between Ephemeris Time (ET) and LMST at the MSL landing site GC (Gale Crater, final target) for the landing date/time 2012-08-06T05:17:45 using SPICE SCLK time conversion routines/tools. Version -------------------------------------------------------- 2.0.0 -- June 07, 2012 -- BVS/NAIF This file provdes the same ET-LMST correlation as msl_lmst_gc120806_v1.tsc. References -------------------------------------------------------- 1. SCLK Required Reading Document Implementation Details -------------------------------------------------------- LMST for MSL at the landing site GC and landing date/time 2012-08-06T05:17:45 can be represented by a simple linear function. The starting point for this function is the ET corresponding to the midnight LMST of the SOL 0 -- 2012-08-05T13:49:59 UTC (or 397446666.183 ET seconds past J2000). This function "runs" at the constant rate of 1.02749125 ET seconds in 1 local Martian second, which is equal the SCLK rate of 88775.24400000 ET seconds in 1 local Martian day that appears in the COEFFICIENTS keyword below. The ID for this clock is chosen to be 76900 to indicate that this is NOT an actual SCLK for the MSL on-board clock but a special SCLK file that enables LMST-ET time conversions using the APIs of the SCLK subsystem of SPICE. LMST Format -------------------------------------------------------- The LMST string, the conversion for which is provided by this SCLK file, consists of four fields: DDDDD:HR:MN:SC:TMSEC where: DDDDD -- count of LMST (SOL) days (0..36525) HR -- count of LMST hours (0..23) MN -- count of LMST minutes (0..59) SC -- count of LMST seconds (0..59) TMSEC -- count of LMST 10-microsecond ticks (0..99999) Usage -------------------------------------------------------- In order to use the SPICELIB SCLK family routines to convert MSL LMST at the landing site GC to ET and vice versa, this file must be loaded into the user's program by a call to the FURNSH routine CALL FURNSH( 'this_file_name' ) (FORTRAN) furnsh_c ( "this_file_name" ); (C) cspice_furnsh, 'this_file_name' (IDL) cspice_furnsh( 'this_file_name' ) (MATLAB) Once loaded, the routine SCE2S can be used to convert an ET time to an LMST string in the format DDDDD:HR:MN:SC:TMSEC: CALL SCE2S( -76900, ET, LMST ) (FORTRAN) sce2s_c ( -76900, et, maxlen, lmst ); (C) cspice_sce2s, -76900, et, lmst (IDL) lmst = cspice_sce2s( -76900, et ); (MATLAB) and the routine SCS2E can be used for backward conversion -- from LMST in DDDDD:HR:MN:SC:TMSEC format to ET: CALL SCS2E( -76900, LMST, ET ) (FORTRAN) scs2e_c ( -76900, lmst, &et ); (C) cspice_scs2e, -76900, lmst, et (IDL) et = cspice_scs2e( -76900, lmst ) (MATLAB) Inquiries -------------------------------------------------------- If you have any questions regarding this file contact NAIF at JPL Charles H. Acton, Jr (818) 354-3869 Chuck.Acton@jpl.nasa.gov Boris V. Semenov (818) 354-8136 Boris.Semenov@jpl.nasa.gov Kernel DATA -------------------------------------------------------- \begindata SCLK_KERNEL_ID = ( @2012-06-07-10:25:10 ) SCLK_DATA_TYPE_76900 = ( 1 ) SCLK01_TIME_SYSTEM_76900 = ( 1 ) SCLK01_N_FIELDS_76900 = ( 5 ) SCLK01_MODULI_76900 = ( 36525 24 60 60 100000 ) SCLK01_OFFSETS_76900 = ( 0 0 0 0 0 ) SCLK01_OUTPUT_DELIM_76900 = ( 2 ) SCLK_PARTITION_START_76900 = ( 0.00000000000000E+00 ) SCLK_PARTITION_END_76900 = ( 3.15576000000000E+14 ) SCLK01_COEFFICIENTS_76900 = ( 0.0000000000000E+00 397446666.183 88775.24400000 ) \begintext