\begintext FILENAME = "new-horizons_112.tsc" CREATION_DATE = "16-Oct-2006" NEW HORIZONS Spacecraft Clock Kernel (SCLK) =========================================================================== This file is a SPICE spacecraft clock (SCLK) kernel containing information required for time conversions involving the on-board NEW HORIZONS spacecraft clock. Version -------------------------------------------------------- NEW HORIZONS SCLK Kernel Version: Version 1.0 -- December 14, 2005 -- Stan Cooper Initial (seed) time coefficients triplet set for a launch time of 2006-011-14:11:00 EST, which equals 2006-011-19:11:00 UTC. Note that this was set using the new value of 33 leap seconds that comes into effect a few days before launch. Version 0.4 -- November 15, 2005 -- Stan Cooper Corrected the statement "SPICE uses linear interpolation" to "SPICE uses linear extrapolation". This was confirmed earlier with Scott Turner as noted in the MESSENGER SCLK kernels. Version 0.3 -- May 11, 2005 -- Stan Cooper Modified file header to avoid loss of header text when kernel is automatically updated. Also, added FILENAME and CREATION_DATE fields that are automatically updated. Version 0.2 -- June 25, 2003 -- Scott Turner The number of digits representing fractional seconds present in the TDT component of the SCLK coefficient triples were inadequate for NEW HORIZONS' requirements. The field now contains 6 digits instead of 3. Version 0.1 -- June 24, 2003 -- Scott Turner This kernel was created as an initial input to the NEW HORIZONS SCLK update process. It provides values for the fields required to handle the SCLK string format, as well as the baseline units of the clock correlation coefficients that the update process is to introduce or correct. The initial clock rate established in this file assumes no drift from the parallel time system (TDT). Further the clock coefficients indicate the clock starts on the following epoch: 1/0:0 (SCLK) 01-JAN-2003-00:01:04.184 (TDT) The end of the first partition is currently defined as the value in ticks of the rollover of the spacecraft clock. Usage -------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this SCLK kernel must 'load' the kernel, normally during program initialization. Loading the kernel associates the data items with their names in a data structure called the 'kernel pool'. The SPICELIB routine FURNSH loads text kernel files, such as this one, into the pool as shown below: FORTRAN: CALL FURNSH ( SCLK_kernel_name ) C: furnsh_c ( SCLK_kernel_name ); Once loaded, the SCLK time conversion routines will be able to access the necessary data located in this kernel for their designed purposes. References -------------------------------------------------------- 1. "SCLK Required Reading" Inquiries -------------------------------------------------------- If you have any questions regarding this file or its usage, contact: Scott Turner (443)778-1693 Scott.Turner@jhuapl.edu Kernel Data -------------------------------------------------------- The first block of keyword equals value assignments define the type, parallel time system, and format of the spacecraft clock. These fields are invariant from SCLK kernel update to SCLK kernel update. The NEW HORIZONS spacecraft clock is represented by the SPICE type 1 SCLK kernel. It uses TDT, Terrestrial Dynamical Time, as its parallel time system. \begindata SCLK_KERNEL_ID = ( @2006-10-16T15:34:11 ) SCLK_DATA_TYPE_98 = ( 1 ) SCLK01_TIME_SYSTEM_98 = ( 2 ) \begintext In a particular partition of the NEW HORIZONS spacecraft clock, the clock read-out consists of two separate stages: 1/18424652:24251 The first stage, a 32 bit field, represents the spacecraft clock seconds count. The second, a 16 bit field, represents counts of 20 microsecond increments of the spacecraft clock. The following keywords and their values establish this structure: \begindata SCLK01_N_FIELDS_98 = ( 2 ) SCLK01_MODULI_98 = ( 4294967296 50000 ) SCLK01_OFFSETS_98 = ( 0 0 ) SCLK01_OUTPUT_DELIM_98 = ( 2 ) \begintext This concludes the invariant portion of the SCLK kernel data. The remaining sections of the kernel may require updates as the clock correlation coefficients evolve in time. The first section below establishes the clock partitions. The data in this section consists of two parallel arrays, which denote the start and end values in ticks of each partition of the spacecraft clock. SPICE utilizes these two arrays to map from spacecraft clock ticks, determined with the usual modulo arithmetic, to encoded SCLK--the internal, monotonically increasing sequence used to tag various data sources with spacecraft clock. \begindata SCLK_PARTITION_START_98 = ( 0.00000000000000e+00 ) SCLK_PARTITION_END_98 = ( 2.14748364799999e+14 ) \begintext The remaining section of the SCLK kernel defines the clock correlation coefficients. Each line contains a 'coefficient triple': Encoded SCLK at which Rate is introduced. Corresponding TDT Epoch at which Rate is introduced. Rate in TDT (seconds) / most significant clock count (~seconds). SPICE uses linear extrapolation to convert between the parallel time system and encoded SCLK. The triples are stored in the array defined below. The first time triplet below was entered manually and represents the approximate time (in TDT) at which MET is set to zero. The plan for New Horizons is that MET will be set to roll over to zero at the beginning of the daily launch window. Note that the conversion from UTC to TDT used 33 leap seconds. \begindata SCLK01_COEFFICIENTS_98 = ( 0 @19-JAN-2006-18:09:05.184000 1.00000000000 2766250000 @20-JAN-2006-09:31:12.483494 1.00000000905 5196350000 @20-JAN-2006-23:01:14.483934 1.00000000931 9606650000 @21-JAN-2006-23:31:20.484755 1.00000000939 13926500000 @22-JAN-2006-23:31:17.485566 1.00000000919 18246400000 @23-JAN-2006-23:31:15.486360 1.00000000938 22566350000 @24-JAN-2006-23:31:14.487170 1.00000000892 26885950000 @25-JAN-2006-23:31:06.487941 1.00000000954 31206000000 @26-JAN-2006-23:31:07.488765 1.00000001357 44169100000 @29-JAN-2006-23:32:09.492284 1.00000007324 48495750000 @30-JAN-2006-23:34:22.498622 0.99999993415 52805100000 @31-JAN-2006-23:30:49.492947 1.00000001019 57124700000 @01-FEB-2006-23:30:41.493827 1.00000001790 91701750000 @09-FEB-2006-23:36:22.506207 0.99999998303 104645200000 @12-FEB-2006-23:30:51.501814 1.00000000852 108962750000 @13-FEB-2006-23:30:02.502550 1.00000000833 117603550000 @15-FEB-2006-23:30:18.503989 1.00000000799 134885300000 @19-FEB-2006-23:30:53.506750 1.00000000804 139201550000 @20-FEB-2006-23:29:38.507444 1.00000000759 143531500000 @21-FEB-2006-23:32:57.508101 1.00000000759 151982150000 @23-FEB-2006-22:29:50.509384 1.00000000729 165123050000 @26-FEB-2006-23:30:08.511299 1.00000000724 169440450000 @27-FEB-2006-23:29:16.511924 1.00000000698 173760250000 @28-FEB-2006-23:29:12.512527 1.00000000697 182401100000 @02-MAR-2006-23:29:29.513731 1.00000000679 195001700000 @05-MAR-2006-21:29:41.515442 1.00000000641 203280050000 @07-MAR-2006-19:29:08.516504 1.00000000611 212639700000 @09-MAR-2006-23:29:01.517648 1.00000000607 229381150000 @13-MAR-2006-20:29:30.519679 1.00000000572 246746750000 @17-MAR-2006-20:58:02.521664 1.00000000530 276812450000 @24-MAR-2006-19:59:56.524853 1.00000000473 293993950000 @28-MAR-2006-19:27:06.526478 1.00000000460 302633400000 @30-MAR-2006-19:26:55.527272 1.00000000453 306953150000 @31-MAR-2006-19:26:50.527663 1.00000000459 319912550000 @03-APR-2006-19:26:38.528852 1.00000000411 324052200000 @04-APR-2006-18:26:31.529192 1.00000000448 330712800000 @06-APR-2006-07:26:43.529789 1.00000000413 333591800000 @06-APR-2006-23:26:23.530027 1.00000000423 338271950000 @08-APR-2006-01:26:26.530423 1.00000000375 354289800000 @11-APR-2006-18:25:43.531624 1.00000000371 362929150000 @13-APR-2006-18:25:30.532265 1.00000000361 388847050000 @19-APR-2006-18:24:48.534138 1.00000000322 392986650000 @20-APR-2006-17:24:40.534405 1.00000001251 399115100000 @22-APR-2006-03:27:29.535938 0.99999999778 409184950000 @24-APR-2006-11:24:06.535490 1.00000000325 417824150000 @26-APR-2006-11:23:50.536052 1.00000000297 423224000000 @27-APR-2006-17:23:47.536373 1.00000000301 446442200000 @03-MAY-2006-02:23:11.537770 1.00000000303 450761650000 @04-MAY-2006-02:23:00.538032 1.00000000407 456701700000 @05-MAY-2006-11:23:01.538515 1.00000000365 457646000000 @05-MAY-2006-16:37:47.538584 1.00000000220 472359600000 @09-MAY-2006-02:22:19.539231 1.00000000256 480458600000 @10-MAY-2006-23:21:59.539645 1.00000000390 480997450000 @11-MAY-2006-02:21:36.539687 1.00000000246 488285850000 @12-MAY-2006-18:51:04.540046 1.00000000349 489576650000 @13-MAY-2006-02:01:20.540136 1.00000000250 502056250000 @15-MAY-2006-23:21:12.540761 1.00000000260 506375750000 @16-MAY-2006-23:21:02.540986 1.00000000241 513755750000 @18-MAY-2006-16:21:02.541341 1.00000000245 525455300000 @21-MAY-2006-09:20:53.541914 1.00000000216 532292800000 @22-MAY-2006-23:20:03.542210 1.00000000364 532471600000 @23-MAY-2006-00:19:39.542223 1.00000000222 549933200000 @27-MAY-2006-01:20:11.543000 1.00000000215 566849800000 @30-MAY-2006-23:19:03.543727 1.00000000206 579809400000 @02-JUN-2006-23:18:55.544261 0.99999999802 579985850000 @03-JUN-2006-00:17:44.544254 1.00000000192 601479400000 @07-JUN-2006-23:42:15.545080 1.00000000219 605723700000 @08-JUN-2006-23:17:01.545266 1.00000000186 615804000000 @11-JUN-2006-07:17:07.545641 1.00000000200 620121000000 @12-JUN-2006-07:16:07.545814 1.00000000269 627320850000 @13-JUN-2006-23:16:04.546202 1.00000000182 671966000000 @24-JUN-2006-07:17:47.547831 1.00000000171 683473200000 @26-JUN-2006-23:13:31.548224 1.00000000169 687792600000 @27-JUN-2006-23:13:19.548370 1.00000000484 696435700000 @29-JUN-2006-23:14:21.549206 0.99999997595 697510350000 @30-JUN-2006-05:12:34.548689 1.00000000162 714967950000 @04-JUL-2006-06:11:46.549253 1.00000000154 722422650000 @05-JUL-2006-23:36:40.549482 1.00000000534 730811950000 @07-JUL-2006-22:13:06.550378 0.99999999977 748087600000 @11-JUL-2006-22:11:39.550298 1.00000000139 752654950000 @12-JUL-2006-23:34:06.550425 1.00000000177 753842350000 @13-JUL-2006-06:09:54.550467 1.00000000152 761042150000 @14-JUL-2006-22:09:50.550686 1.00000000144 775259250000 @18-JUL-2006-05:08:52.551095 1.00000000135 782639000000 @19-JUL-2006-22:08:47.551294 1.00000000131 787138350000 @20-JUL-2006-23:08:34.551412 1.00000000145 799738850000 @23-JUL-2006-21:08:44.551777 1.00000000134 808195200000 @25-JUL-2006-20:07:31.552004 1.00000000138 832676000000 @31-JUL-2006-12:07:47.552681 1.00000000118 838970850000 @01-AUG-2006-23:06:04.552830 1.00000000250 840049800000 @02-AUG-2006-05:05:43.552884 1.00000000123 844369150000 @03-AUG-2006-05:05:30.552990 1.00000000129 858589850000 @06-AUG-2006-12:05:44.553358 1.00000000125 870285400000 @09-AUG-2006-05:04:15.553651 1.00000000112 877902800000 @10-AUG-2006-23:23:23.553821 1.00000000132 894586250000 @14-AUG-2006-20:04:32.554262 1.00000000113 903834150000 @16-AUG-2006-23:27:10.554471 1.00000000126 908154500000 @17-AUG-2006-23:27:17.554580 1.00000000129 917620950000 @20-AUG-2006-04:02:46.554824 1.00000000109 929752450000 @22-AUG-2006-23:26:36.555088 1.00000000117 939037850000 @25-AUG-2006-03:01:44.555306 1.00000000113 959994900000 @29-AUG-2006-23:27:25.555781 1.00000000107 1016074350000 @11-SEP-2006-23:00:34.556977 1.00000000114 1026686350000 @14-SEP-2006-09:57:54.557218 1.00000000097 1041985000000 @17-SEP-2006-22:57:27.557516 1.00000000100 1052602800000 @20-SEP-2006-09:56:43.557729 1.00000000095 1069700750000 @24-SEP-2006-08:56:02.558053 1.00000000087 1075638050000 @25-SEP-2006-17:55:08.558156 1.00000000087 1093818600000 @29-SEP-2006-22:55:19.558474 1.00000000096 1105704700000 @02-OCT-2006-16:57:21.558702 1.00000000078 1111139050000 @03-OCT-2006-23:08:48.558787 1.00000000087 1134136500000 @09-OCT-2006-06:54:37.559189 1.00000000083 1161854200000 @15-OCT-2006-16:53:51.559648 1.00000000087 )