PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2019-02-22 NOTE = "This file describes the files in the extras/mk directory of this volume." END_OBJECT = TEXT END Meta-kernels for the Dawn Mission to Vesta and Ceres ==================================================== This directory contains the meta-kernel files (a.k.a ``furnsh'' files) that provide lists of the archived kernels included in this data set suitable for loading into a SPICE-based application via the high level SPICE data loader routine FURNSH. Using these meta-kernels makes it easy to load with one call a comprehensive SPICE data collection for a given period. Like the text kernels archived in this data set, these meta-kernels are UNIX text files that have lines terminated with a line feed character, LF (ASCII 10). The names of the primary meta-kernels containing complete sets of kernels, provided in this directory follow this pattern: dawn_YYYY_vVV.tm where ``YYYY'' is the year covered by the kernels listed in the file and ``VV'' is the file version. The names of additional meta-kernels listing only all part DSKs comprising a particular shape model follow this pattern: dawn_BODY_PRO_RESL_vV.tm where ``BODY'' is ``vesta'' or ``ceres'', ``PRO'' is the producer -- ``dlr'' (for the DAWN FC Team, DLR) or ``grv'' (for the DAWN Gravity Team, JPL), ``RESL'' is the model resolution (e.g. ``m100'' for the 100-m spatial resolution), and ``V'' is the file version. Multiple versions of a meta-kernel for the same year may exist if new kernels were added to the archive in a later release and the meta-kernel for that year had to be updated to incorporate them. The reasons for adding new kernels include (but are not limited to) adding new kinds of kernels, adding new versions of existing kernels containing more complete or more accurate data, and adding new versions of existing kernels superseding the existing kernels that had errors. If more than one meta-kernel file for the same year is present, then the file with the latest version number supersedes all earlier versions. The latest meta-kernels can be loaded together in in chronological order by the year to which they apply. (Note that on some environments loading too many kernels at once may slow down data access.) Although the meta-kernels were created such that on a UNIX workstation they can be loaded into a SPICE-based application directly from the root directory of the data set -- because the PATH_VALUES keyword is set to './data' and '/' is used as the path delimiter -- it is recommended that users make local copies of these files and update the PATH_VALUES keyword in each of them to point to the actual location of the data set's 'data' directory on their system. Additional changes including replacing '/' and '\' in all path specifications and converting UNIX line terminators to terminators native to the user's system may be required to use these meta-kernels on non-UNIX workstation. The following guidelines were followed to pick and set priority -- determined by the order in which the kernel files are listed, with the latest one taking precedence -- for the kernel files included in the primary meta-kernels: - the latest archived versions of LSK, PCK, SCLK, IK, and FK were included - only SSD/Grav asteroid ephemeris SPKs were included - both NAV and SSD/Grav reconstructed spacecraft SPKs were included, with the SSD/Grav SPKs listed with higher priority - if any predictive CKs were included, they had a lower priority (listed earlier) than reconstructed CKs and were used when the reconstructed CKs did not provide coverage - spacecraft bus (SC) CKs were included with the highest priority of the CKs, followed by VIR and solar array (SA) CKs - Vesta- and Ceres-specific PCKs were listed with the higher priority over the generic SPICE PCK - the Gravity Team's ICQ 512 DSK for Ceres, chosen solely for performance reasons, was included in MKs for all Ceres mission years Contact Information =================== Regarding Dawn project specific information provided in this data set and for general information about SPICE system, contact: 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