PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2010-08-30 NOTE = "LRO SCL-Kernel Information" END_OBJECT = TEXT END General Information About SPICE SCL-Kernels =========================================== In the SPICE system, Spacecraft Clock (or SCL) -kernel contains a set of information required to perform a mapping between Ephemeris time (ET) and spacecraft on-board time (SCLK). The spacecraft clock coefficient information contained in SCLK file can be manipulated using the SPICE Toolkit APIs, calls to which can be integrated into user application programs. The information regarding how to obtain the SPICE system toolkit for a number of languages and computer platforms is located in the ``/software'' subdirectory of the main directory of this data set. Refer to the ``sclk.req'' document provided with the toolkit to get more information about conversion between ET and spacecraft clock times. LRO SCL-kernels Contained in This Data Set ========================================== The SCLK kernel will be cumulative file for the entire mission. During the prime mission phase, the clock on board the LRO orbiter should be accurate enough that it should never need adjustment baring some anomaly or Orbiter reset, or leap-second adjustment. Clock correlation will be performed approximately twice per day during ground station passes that provide support for the activity. Clock correlation is scheduled and run via a Command and Telemetry procedure during these passes. Nominally, the SCLK kernel will be updated with an entry for each clock correlation activity. File duration: NA; file represents historical concepts for all clock correlations File or Data Generation Frequency: As needed Data Volume: Variable; based on number of LRO clock correlation activities and will increase throughout the mission. Accuracy (if it applies): Time accurate to 1 second. File Name Convention -------------------- The LRO on-board clock SCLK files included in the data set shall be named according to the following naming scheme: __. where File Designator = [10 characters] token identifying the file; is "lro_clkcor" for LRO on-board clock SCLK files. Creation Date = [7 characters], file creation date in DOY form, YYYYDOY; where YYYY => 4 ASCII digits of year ("2008"-"2013") DOY => 3 ASCII digits for day of year ("001"-"366"). Version = [3 characters] file version, vNN; where NN => a two-digit version number; the initial version is "00", next is "01" ... up to "99". File Extension = [3characters] Standard file extension for a text SCLK file "tsc". The following is an example of an LRO on-board clock SCLK file name: - LRO on-board clock SCLK File: lro_clkcor_2009015_v01.tsc Kernel File Details =================== The most detailed description of the data in an SCLK file is provided in metadata included inside the description area of the file. This information can be viewed using any text editor program. Contact Information =================== Regarding Lunar Reconnaissance Orbiter project specific information provided in this data set contact: Rick Saylor (301)-614-1354 Richard.S.Saylor@nasa.gov address: NASA Goddard Space Flight Center (GSFC) Mail Stop 451.0 Building 12 Room N233 Greenbelt MD 20771