PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2019-02-21 NOTE = "DAWN C-Kernel Information" END_OBJECT = TEXT END General Information About SPICE C-Kernels ========================================= In the SPICE system, pointing data for an instrument platform, or for a specific instrument, are stored C-kernels. The pointing of a platform or an instrument is often expressed in terms of a transformation matrix from some standard inertial reference frame to a instrument-fixed frame. In the past, the instrument was often a camera, and the transformation was thus dubbed the ``C-matrix''; hence the choice of C as the name for the pointing kernel. The data contained in C-kernel files can be accessed and manipulated by a collection of FORTRAN 77 subroutines which are part of the SPICELIB library or C functions which are part of the CSPICE library. These subroutines/functions can be integrated into user application programs. The SPICE system toolkit for a number of computer platforms or information regarding how it can be obtained is located in the ``/software'' subdirectory of the main directory of this data set. To use C-kernels, a Spacecraft Clock Kernel (SCLK) is required. Also, for C-Kernels containing orientation of a project-defined frames, a Frame Definitions File is required. Refer to the ``ck.req'' document provided with the toolkit or available from the NAIF Node of PDS if SPICE toolkit is not included with this data set to get more information on how to access C-kernel data. DAWN C-kernels Contained in This Data Set ========================================= The following DAWN C-kernels are provided in this data set (only name portion of the file name is shown; the extension of all file names is ``.bc''): DAWN Spacecraft Orientation CK Files: dawn_sc_BEG_END[_vV] CK files providing actual telemetry-based orientation of the DAWN spacecraft bus for the BEG to END time period. The dates are specified in the YYMMDD format. The appendage [_vV], in which V is the version number, is omitted for version 1. dawn_sc_pred_SEQID[_VV] CK files providing the predicted orientation of the DAWN spacecraft bus in which SEQID is the sequence/modeling run/NAV ephemeris update ID and VV is the version number. dawn_sc_fN_xxxxxxxxx CK files providing the reconstructed orientation determined by the FC Team at DLR based on the FC``N'' images for the SCLK range ``xxxxxxxxx''. DAWN Solar Arrays (SAs) Orientation CK Files: dawn_sa_BEG_END[_vV] CK files providing actual telemetry-based orientation of the DAWN solar arrays for the BEG to END time period. The dates are specified in the YYMMDD format. The appendage [_vV], in which V is the version number, is omitted for version 1. DAWN Visual and Infrared Imaging Spectrometer (VIR) Orientation CK Files: dawn_vir_YYDOYHRMN_V CK files providing actual telemetry-based orientation of the DAWN VIR instrument. YY is the year, DOY is the day of year, HR is the hour, MN is the minute of a date/time that is a few hours before the actual start of the file's data coverage, and V is the version number. dawn_vir_zero CK file containing the fixed orientation representing the "zero" mirror position at which the DAWN_VIR_SCAN and DAWN_VIR frames are co-aligned. DAWN Framing Camera (FC) Orientation CK Files: dawn_fc_vV CK file containing the alignment of the FC2 frame relative to the spacecraft frame. This CK is used instead of simply putting the alignment into a fixed offset frame because the alignment changed during Vesta to Ceres transfer, resulting in different alignment values applicable to the Vesta mission and Ceres mission time periods. This CK should be used with DAWN FK v13 or later. dawn_fc2_BEG_END_SOL_vV CK file containing the FC2 camera frame orientation with respect to the inertial space for selected images during BEG to END period, based on solution SOL (e.g. grv171219 for the Gravity Team 2017-12-19 solution). Kernel File Details =================== The most detailed description of the data in a binary CK file is provided in metadata included inside the comment area of the file. This information can be viewed using utility programs COMMNT and SPACIT included into the NAIF Toolkit. Gaps in CK Coverage =================== The following reconstructed CKs have irrecoverable gaps in coverage due to safe modes, FSW reboots, and other anomalies: dawn_sc_071126_071202.bc -- FSW 7.0 reboot on 2007-11-28 dawn_sc_090413_090419.bc -- FSW 8.0 reboot on 2009-04-14 dawn_sc_100614_100620.bc -- FSW 9.0 reboot on 2010-06-16 dawn_sc_100719_100725.bc -- station data loss on 2010-07-26 dawn_sc_100726_100801.bc -- station data loss on 2010-07-26 dawn_sc_110411_110417.bc -- FSW 10.0 reboot on 2011-04-12 dawn_sc_110919_110925.bc -- safe mode, start early 2011-09-22 dawn_sc_120109_120115.bc -- safe mode, start 2012-01-14T06:49 dawn_sc_120116_120122.bc -- safe mode, end 2012-01-17T??:?? dawn_sc_120220_120226.bc -- safe mode, start 2012-02-22T??:?? dawn_sc_120220_120226.bc -- safe mode, start 2012-02-22T??:?? dawn_sc_120625_120701.bc -- lost playback due to a DSN problem. dawn_sc_140908_140914.bc -- safe mode, recovery at 2014-09-14T??:?? dawn_sc_181022_181028.bc -- lack of high rate telemetry near EOM dawn_sc_181029_181031.bc -- lack of high rate telemetry near EOM Contact Information =================== Regarding DAWN project specific information provided in this data set and for general information about SPICE system: Boris Semenov (818)-354-8136 Boris.Semenov@jpl.nasa.gov address: Navigation and Ancillary Information Facility (NAIF) Jet Propulsion Laboratory MS 301-125L 4800 Oak Grove Drive Pasadena CA 91109 USA