KPL/SCLK PHX SCLK File Implementing LMST at B1 Landing Site, 2008-06-05 Landing =========================================================================== This file is a SPICE spacecraft clock (SCLK) kernel that implements Local Mean Solar Time (LMST). This file contains information required to convert between LMST at the PHX landing site B1 and Ephemeris Time (ET) using SPICE SCLK time conversion routines/tools. Version -------------------------------------------------------- 1.0.0 -- November 1, 2006 -- BVS/NAIF Initial Release. References -------------------------------------------------------- 1. SCLK Required Reading Document 2. Phoenix Planetary Constants and Models Document (PHX-377-515) Implementation Details -------------------------------------------------------- From LTST and LMST equations in [2], one could derive that LMST for PHOENIX at the landing site B1 and launch at the end of the launch window resuting in landing on June 5, 2008 can be presented by a simple linear function. The starting point for this function will be ET corresponding to the midnight LMST of the SOL 0 -- 2008-06-04, 20:33:04.440 (or 265883584.440 ET seconds past J2000.) This function will "run" at the contant 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 day appearing in the COEFFICIENTS keyword below. The ID for this clock is chosen to be 84900 to indicate that this is NOT a actual SCLK for the PHX but rather a convenient way to implement LMST using SCLK subsystem of SPICE. LMST Format -------------------------------------------------------- The LMST string, the conversion for which is provided by this SCLK file, consists of four fields: DDD:HR:MN:SC where: DDD -- count of LMST (SOL) days HR -- count of LMST hours MN -- count of LMST minutes SC -- count of LMST seconds Usage -------------------------------------------------------- This file must be loaded into the user's program by a call to the FURNSH subroutine CALL FURNSH( 'this_file_name' ) furnsh_c ( "this_file_name" ); in order to use the SPICELIB SCLK family of subroutines to convert PHX LMST at the landing site B1 to ET and vice versa. Once loaded, the SCE2S/sce2s_c.f routines can be used to convert an ET time to an LMST string in the format DDD:HR:MN:SC: CALL SCE2S( -84900, ET, LMST ) sce2s_c ( -84900, et, maxlen, lmst ); and the routines SCS2E/scs2e_c can be used for backward conversion -- from LMST in DDD:HR:MN:SC format to ET: CALL SCS2E( -84900, LMST, ET ) scs2e_c ( -84900, lmst, &et ); Production/History of this SCLK file -------------------------------------------------------- This file was generated manually using the PHOENIX LMST definition provided in [2] and the LMST0 reference point computed for the landing site B1. 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 = ( @2006-11-01/12:01 ) SCLK_DATA_TYPE_84900 = ( 1 ) SCLK01_TIME_SYSTEM_84900 = ( 2 ) SCLK01_N_FIELDS_84900 = ( 4 ) SCLK01_MODULI_84900 = ( 24855 24 60 60 ) SCLK01_OFFSETS_84900 = ( 0 0 0 0 ) SCLK01_OUTPUT_DELIM_84900 = ( 2 ) SCLK_PARTITION_START_84900 = ( 0.0000000000000E+00 ) SCLK_PARTITION_END_84900 = ( 1.0995116277750E+12 ) SCLK01_COEFFICIENTS_84900 = ( 0.0000000000000E+00 265883584.440 88775.24400000 ) \begintext