PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2024-02-01 NOTE = "This file describes the files in the extras/mk directory of this archive." END_OBJECT = TEXT END Meta-kernels for the Cassini mission ==================================== 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 meta-kernels provided in this directory follow this pattern: cas_YYYY_vVV.tm when ``YYYY'' is the year covered by the kernels listed in the file and ``VV'' 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 the yearly order to provide coverage for more than one year. (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 terminator 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 these meta-kernels: - the latest archived LSK is included. - the latest archived version of generic PCK is included (see WARNING below regarding generic PCKs). - the latest Enceladus PCK is included. - the latest archived versions of the project FK, rocks FK, dynamic frames FK, and MIMI frames FK are included. - the latest archived version of IK for each instrument are included. - the final reconstructed archived SCLK is included. - a subset of small satellite SPKs providing the most complete coverage are included. If two or more SPKs covered the same time span for a body were included, the latest SPK was listed last for higher priority. - the latest archived versions of post-mission uniform reconstruction SPKs are included. If two or more SPKs covered the same time span for a body were included, the latest SPK was listed last for higher priority. - both the final predicted and operational reconstructed spacecraft orientation CKs are included with the reconstructed CKs taking precedence (listed last) and predicted CKs having lower priority and used when the reconstructed CKs do not provide coverage. To make sure that when meta-kernels for multiple years are loaded together predicted CKs extending past year's boundaries never masks reconstructed CKs from previous/next years, each yearly meta-kernel includes enough reconstructed CKs to fully cover the span of all predicted CKs listed in it. This results in combined coverage spans of reconstructed and predicted CKs provided in a yearly meta-kernel extending days or even weeks outside the year's boundaries. - the latest archived CDA CK is included. - the latest archived MIMI/LEMMS CKs are included. - the latest archived CAPS CKs are included. - the lowest resolution global shape model DSK of Enceladus is included. - no ISS c-smithed CKs are included due to the very sparse coverage provided by these files. - no EK files are included due to the low likelihood that EKs would be needed for a SPICE-based application using the Cassini SPICE data. WARNING: the latest generic PCK files included in the lists of kernels in these meta-kernels do not provide all parameters included in the CASSINI-specific PCKs and, for some parameters present in both types of files, provide different values compared to the values in the CASSINI-specific PCKs. It is the user's responsibility to identify whether a CASSINI-specific PCK(s) is(are) needed for his/her application and to use this(these) PCK(s) in addition to or instead of the generic PCKs in these meta-kernels. Contact Information =================== Regarding Cassini 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